politecnico di milano prevention activities in lca of municipal waste

Transcription

POLITECNICO DI MILANO
FACOLTÀ DI INGEGNERIA CIVILE, AMBIENTALE E TERRITORIALE
Corso di Laurea Specialistica in Ingegneria per l’Ambiente e il Territorio
PREVENTION ACTIVITIES IN LCA OF MUNICIPAL WASTE
MANAGEMENT SYSTEMS: MODELS PROPOSAL AND
CASE STUDY FOR DRINKING WATER
Relatore:
Ing. Mario Grosso
Correlatore: Ing. Lucia Rigamonti
Tesi di Laurea Specialistica di
Simone Nessi
Matr. 722035
Anno Accademico 2009/2010
Ringraziamenti
Desidero esprimere innanzitutto la mia gratitudine al professor Mario Grosso per avermi
appoggiato e dato fiducia nell’intraprendere e portare avanti questo progetto di tesi, e a Lucia
Rigamonti per i preziosi consigli nonché per le precise e puntuali revisioni dell’elaborato e di
tutto il materiale ad esso relativo.
Ringrazio anche Emmanuel Gentil per la sua disponibilità nel ricoprire il ruolo di
controrelatore per questa tesi.
Un vivo ringraziamento va poi a tutte le persone senza la cui collaborazione non sarebbe stato
possibile portare a termine il lavoro, in ordine di comparsa: Maurizio Briccola e Anna Giugno
della società di imbottigliamento di acque minerali esaminata, Carlo Carrettini e Chiara
Pagano di Metropolitana Milanese e Leonardo Rossi di Publiacqua.
Per aver fornito importanti indicazioni, consigli o materiali, ringrazio, sempre in ordine di
comparsa, anche Saverio Zetera di A2A, Michele Giavini di ARS Ambiente, Julian Cleary
della University of Toronto, Gian Andrea Blengini del Politecnico di Torino, Simone
Manfredi del JRC, Daniele Gallo, Paolo Neri di ENEA, il signor Cottarelli di Norda, Silvia
Parola di Fonti di Vinadio, Andreas Detzel dell’IFEU, Luca Calcatelli di Marchi Industriale, il
signor Costa di Braia e Rino Spotti di Akomag.
Immensa gratitudine va inoltre ai miei famigliari per avermi dato il loro indispensabile
appoggio e sostegno durante tutti questi anni, permettendomi di portare a termine con serenità
gli studi.
Grazie di cuore a Laura per avermi sempre ascoltato, incoraggiato e pazientemente
sopportato.
Non posso poi dimenticar di ringraziare i compagni con cui ho condiviso i momenti di studio,
e non solo, in questi anni di università, e che hanno contribuito a renderli sicuramente più
leggeri e spensierati, in primis Luca, Maurino e Stefania, ma anche Lela, Petak e Lo Zio.
Grazie infine a tutti gli amici che, anche se non fisicamente, ci sono sempre stati, in
particolare Liro, Duro e Roberta.
Table of contents
Table of contents...................................................................................................................5
List of figures .......................................................................................................................9
List of tables .......................................................................................................................17
Abstracts .............................................................................................................................27
Executive summary ............................................................................................................31
Introduction ........................................................................................................................49
Chapter 1: Background on waste prevention ...................................................................53
1.1 Legislative framework at European level: waste hierarchy and definitions...................53
1.2 Possible classification of waste prevention activities ...................................................60
1.3 Review of major prevention activities targeting municipal solid waste ........................67
1.4 Waste prevention and life cycle thinking .....................................................................78
1.5 Consumption patterns of drinking water in Italy ..........................................................79
Chapter 2: LCA and waste prevention..............................................................................85
2.1 Introduction to LCA ....................................................................................................85
2.2 LCA applied to integrated solid waste management systems .......................................88
2.3 LCA and waste prevention ..........................................................................................91
2.3.1 Adjustments to traditional waste management oriented LCA and literature models
review ...........................................................................................................................93
2.3.1.1 The WasteMAP LCA model .......................................................................95
2.3.1.2 First proposal of a model: the Integrated Scenarios Waste Prevention Model
(ISWPM) ..............................................................................................................101
2.3.1.3 Second proposal of a model: the Separate Scenarios Waste Prevention
Model (SSWPM) ..................................................................................................106
2.3.2 Final remarks......................................................................................................109
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Table of contents
Chapter 3: Models comparison: a practical application.................................................111
3.1 Introduction...............................................................................................................111
3.2 Waste generation and composition ............................................................................112
3.2.1 Gross waste generation and composition.............................................................112
3.2.2 Plastic waste fraction composition ......................................................................116
3.3 Waste management system description and inventory ...............................................119
3.3.1 Collection efficiencies ........................................................................................119
3.3.2 Materials selection and recovery.........................................................................120
3.3.3 Energy recovery (incineration)............................................................................122
3.4 LCA modelling of scenarios ......................................................................................130
3.4.1 WasteMAP LCA model.......................................................................................130
3.4.2 Integrated Scenarios Waste Prevention Model (ISWPM).....................................140
3.4.3 Separate Scenarios Waste Prevention Model (SSWPM).......................................145
3.4.4 Comparative considerations ................................................................................151
3.5 Modeling variant .......................................................................................................154
3.5.1 WasteMAP LCA model.......................................................................................155
3.5.2 Integrated Scenarios Waste Prevention Model (ISWPM).....................................158
3.5.3 Separate Scenarios Waste Prevention Model (SSWPM).......................................159
3.5.4 Further comparative considerations.....................................................................160
Chapter 4: Life cycle inventory of scenarios ...................................................................163
4.1 Introduction...............................................................................................................163
4.2 Analysed scenarios and goal definition......................................................................163
4.3 Functional unit and system boundaries ......................................................................165
4.4 Impact assessment categories and characterization methods ......................................165
4.5 Baseline scenario 1 (Utilization of virgin PET one-way bottled water) ......................171
4.5.1 Waste generation and management .....................................................................171
4.5.2 Life cycle inventory of one-way virgin PET bottled water ..................................175
4.6 Baseline scenario 2 (Utilization of recycled PET one-way bottled water) ..................199
4.7 Baseline scenario 3 (Utilisation of PLA one-way bottled water) ................................206
4.7.1 Generalities on polylactic acid (PLA) .................................................................206
4.7.2 Waste generation and management .....................................................................206
4.7.3 Life cycle inventory of PLA one-way bottled water ............................................213
Table of contents
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4.8 Waste prevention scenario 1A (Utilisation of public network water: groundwater from
the tap)............................................................................................................................217
4.8.1 Life cycle inventory of public network water: groundwater from the tap.............218
4.9 Waste prevention scenario 1B (Utilisation of public network water: surface water from
public fountains) .............................................................................................................244
4.9.1 Life cycle inventory of public network water: surface water from public
fountains .....................................................................................................................245
4.10 Waste prevention scenario 2A (Utilisation of refillable glass bottled water).............280
4.10.1 Waste generation and management ...................................................................280
4.10.2 Life cycle inventory of refillable glass bottled water .........................................286
4.11 Waste prevention scenario 2B (Utilisation of refillable PET bottled water)..............299
4.11.1 Description of the packaging system.................................................................299
4.11.2 Waste generation and management ...................................................................301
4.11.3 Life cycle inventory of refillable PET bottled water..........................................302
Chapter 5: Results and sensitivity analysis......................................................................309
5.1 Results of the different modelling approaches ...........................................................309
5.2 Base case results and remarks....................................................................................316
5.2.1 Waste generation ................................................................................................316
5.2.2 LCA results ........................................................................................................317
5.2.2.1 Remarks about tap water scenarios ...........................................................319
5.2.2.2 Remarks about refillable bottled water scenarios ......................................325
5.2.2.3 Remarks about one-way bottled water scenarios .......................................332
5.2.2.4 Water consumptions .................................................................................336
5.3 Sensitivity analysis....................................................................................................338
5.3.1 Introduction ........................................................................................................338
5.3.2 Allocation of consumer purchasing trip burdens (one-way scenarios) .................339
5.3.3 Washing frequency of reusable glass jug and allocation of dishwashing burdens
(tap groundwater scenario) ..........................................................................................342
5.3.4 Transport distance from public fountains to consumers house (tap surface water
scenario)......................................................................................................................344
5.3.5 Typology of containers employed to conserve water (surface water scenario) .....348
5.3.6 Transportation distance between bottling plant and retailers or local distributors
(bottled water scenarios)..............................................................................................350
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Table of contents
5.3.7 Number of uses of refillable bottles (refillable scenarios)....................................353
5.3.8 Upper and lower bounds .....................................................................................356
5.4 Concluding remarks and recommendations................................................................361
Limitations and further research.....................................................................................365
Bibliography .....................................................................................................................367
Appendix A .......................................................................................................................379
Appendix B .......................................................................................................................383
B.1 Airborne emissions of paper and PLA incineration processes....................................383
Appendix C .......................................................................................................................385
C.1 Composition and modelling of detergents employed for filler machine washing .......385
C.2 Composition and modelling of detergents employed for bottles washing...................387
Appendix D .......................................................................................................................389
Appendix E .......................................................................................................................405
List of figures
Figure S.1:
Simplified representation of the system boundaries considered by the Integrated
scenarios waste prevention model for a baseline and a waste prevention scenario
including prevention activities taking place through dematerialization and procedures
for the calculation of the respective impacts ................................................................ 34
Figure S.2:
Simplified representation of the system boundaries considered by the Separated
scenarios waste prevention model for a baseline and a waste prevention scenario
including prevention activities taking place through dematerialization and procedures
for the calculation of the respective impacts ................................................................ 36
Figure S.3:
Global warming impact indicator calculated for all the analysed scenarios with the
respective upper and lower bounds resulting form the sensitivity analysis (the dotted
area in the tap surface water bar specifies the contribution given by water transportation
by car) ........................................................................................................................45
Figure 1.1:
Graphical representation of the concept of waste hierarchy so as described by the recent
Waste Framework Directive 2008/98/EC ....................................................................54
Figure 1.2:
Representation of the position of the various step of the waste hierarchy (Adapted from
ACR+ (2010)) ............................................................................................................58
Figure 1.3:
Evolution of per capita consumptions of bottled water in Italy (Elaboration on data
from Bevitalia (2009)) ................................................................................................ 79
Figure 1.4:
Results of a statistical survey on the reasons that induce consumers to prefer drinking of
mineral water with respect to tap water (Adapted from Temporelli and Cassinelli,
2005)..........................................................................................................................81
Figure 2.1:
Stages of a life cycle assessment (ISO, 2006a) ............................................................ 86
Figure 2.2:
Illustration of the difference between system boundaries of product oriented LCA
(vertical approach) and waste management oriented LCA (horizontal approach) and
their interaction (Adapted from Coleman et al., 2003) .................................................91
Figure 2.3:
Representation of the system boundaries considered by the WasteMAP LCA model for
a waste prevention scenario including one prevention activities taking place through
dematerialization (Adapted from Cleary (2010b)) .......................................................97
Figure 2.4:
Scenarios to be compared when utilising the avoided burden approach version of the
WasteMAP LCA model: sub-systems included and procedure for the calculation of the
respective impacts ......................................................................................................99
Figure 2.5:
Scenarios to be compared when utilising the cut-off approach version of the WasteMAP
LCA model: sub-systems included and procedure for the calculation of the respective
impacts ..................................................................................................................... 100
10
List of figures
Figure 2.6:
Representation of the system boundaries considered by Gallo (2009) for a waste
management system including waste prevention activities (Adapted from Gallo
(2009)) ..................................................................................................................... 102
Figure 2.7:
Simplified representation of the system boundaries considered by the Integrated
Scenarios Waste Prevention Model for a baseline and a waste prevention scenario
including prevention activities taking place through dematerialization....................... 105
Figure 2.8:
Procedure for the calculation of the impacts of the scenarios to be compared through the
Integrated Scenarios Waste Prevention Model and respective included sub-systems ..106
Figure 2.9:
Simplified representation of the system boundaries considered by the Separate
Scenarios Waste Prevention Model for a baseline and a waste prevention scenario
including prevention activities taking place through dematerialization....................... 108
Figure 2.10: Procedure for the calculation of the impacts of the scenarios to be compared through the
Separate Scenarios Waste Prevention Model and respective included sub-systems .... 109
Figure 3.1:
Mass flows within the waste management system of the baseline scenario modelled
through the WasteMAP LCA model and respective ideal boundaries ........................ 132
Figure 3.2:
Mass flows within the DOWN waste management system belonging to the waste
prevention scenario modelled through the WasteMAP LCA model and respective ideal
boundaries ................................................................................................................ 136
Figure 3.3:
Global warming impact indicator calculated through the WasteMAP LCA model for
each analysed scenario and relative difference........................................................... 139
Figure 3.4:
Sub-systems contribution to the global warming impact indicator calculated through the
WasteMAP LCA model for each analysed scenario................................................... 139
Figure 3.5:
through the ISWP model and respective ideal boundaries.......................................... 141
Figure 3.6:
Mass flows within the waste management system of the waste prevention scenario
modelled through the ISWP model and respective ideal boundaries........................... 143
Figure 3.7:
Global warming impact indicator calculated through the ISWP model for each analysed
scenario and relative difference................................................................................. 144
Figure 3.8:
Main processes contribution to the global warming impact indicator calculated through
the ISWP model for each analysed scenario .............................................................. 144
Figure 3.9:
through the SSWP model and respective ideal boundaries ......................................... 147
Figure 3.10: Mass flows within the waste management system of the waste prevention scenario
modelled through the SSWP model and respective ideal system boundaries .............. 149
Figure 3.11: Global warming impact indicator calculated through the SSWP model for each analysed
scenario and relative difference................................................................................. 150
Figure 3.12: Main processes contribution to the global warming impact indicator calculated through
the SSWP model for each analysed scenario ............................................................. 150
List of figures
11
Figure 3.13: Comparison among the global warming impact indicator calculated through the
investigated models for all the examined scenarios.................................................... 153
Figure 3.14: Mass flows within the waste management system of the baseline scenario modelled
through the WasteMAP LCA model and respective ideal boundaries ........................ 155
Figure 3.15: Global warming impact indicator calculated through the WasteMAP LCA model for
each analysed scenario and relative difference........................................................... 157
Figure 3.16: Sub-systems contribution to the global warming impact indicator calculated through the
WasteMAP LCA model for each analysed scenario................................................... 157
Figure 3.17: Mass flows within the waste management system and major processes included in the
systems boundaries of the baseline scenario modelled through the ISWP model ........ 158
Figure 3.18: Major processes included in the systems boundaries of the waste prevention scenario
modelled through the ISWP model............................................................................ 159
Figure 3.19: Mass flows within the waste management system and major processes included in the
systems boundaries of the baseline scenario modelled through the SSWP model ....... 159
Figure 3.20: Major processes included in the systems boundaries of the waste prevention scenario
modelled through the SSWP model........................................................................... 160
Figure 3.21: Comparison among the global warming indicator calculated through the investigated
models for all the considered scenario variants.......................................................... 161
Figure 4.1:
Waste flows within the management system for baseline scenario 1 .......................... 173
Figure 4.2:
Mass flows involving PET bottles in baseline scenario 2........................................... 201
Figure 4.3:
Product systems involved by the same material flow in the case of open-loop recycling
(Ekvall and Tillman,1997) ........................................................................................ 204
Figure 4.4:
Waste flows within the management system for the two subscenarios of baseline
scenario 3 ................................................................................................................. 207
Figure.4.5:
Illustration of at typical scheme of treatment station at the service of the aqueduct of
Milan (Provided by Metropolitana Milanese) ............................................................ 219
Figure 4.6:
Conceptual model of the life cycle of the activated carbon utilised at the treatment
stations at the service of the aqueduct of Milan modelled as a case of closed-loop
recycling................................................................................................................... 225
Figure 4.7:
Simplified layout of the exhausted activated carbon reactivation process at SICAV
(Adapted from SICAV (2009)) ................................................................................. 227
Figure 4.8:
Simplified layout of the Anconella drinking water treatment plant (Adapted from Fabbri
(2010)) ..................................................................................................................... 245
Figure 4.9:
Layout of the H2O PLUS water refinement system (Adapted from Rossi (2007)) ...... 249
Figure 4.10: Simplified layout of the process developed by Aker Solutions for the integrated
generation of chlorine dioxide (Adapted from Barr et al. (2009))............................... 259
Figure 4.11: Generation and structure of non ionic polyacrylamide (Adapted from SNF FLOERGER
(2005)) ..................................................................................................................... 269
12
List of figures
Figure 4.12: Generation and structure of anionic polyacrylamide (Adapted from SNF FLOERGER
(2002)) ..................................................................................................................... 269
Figure 4.13: Generation and structure of cationic polyacrylamide (Adapted from SNF FLOERGER
(2002)) ..................................................................................................................... 270
Figure 4.14: Conceptual model of the life cycle of the activated carbon utilised at the Anconella
plant as a case of closed-loop recycling..................................................................... 272
Figure 4.15: Conceptual model of a refilling system as a case of closed loop recycling. ................ 281
Figure 4.16: Modelling of glass bottles life cycle as a case of closed loop recycling. ..................... 285
Figure 4.17: Modelling of aluminium caps life cycle as a case of closed loop recycling ................ 286
Figure 5.1:
Impact indicators calculated for the recycled PET one-way bottled water scenario by
applying the two different typologies of modelling approach described in paragraph
4.6 ............................................................................................................................ 310
Figure 5.2:
Contribution of the processes of preforms manufacturing and bottles recycling to the
CED indicator for the recycled PET one-way bottled water scenario modelled through
the two different approaches described in paragraph 4.6............................................ 310
Figure 5.3:
Impact indicators calculated for the PLA one-way bottled water scenario by applying
the two different typologies of approach described in paragraph 4.7.2 for the modelling
of PLA composting...................................................................................................311
Figure 5.4:
Contribution of the PLA composting process to the CED and the global warming
indicators for the PLA one-way bottled water scenario.............................................. 312
Figure 5.5:
Contribution by sub processes to the CED and the global warming indicators for PLA
composting modelled through the process specific approach ..................................... 313
Figure 5.6:
Contribution by sub processes to the CED and the global warming indicators for PLA
composting modelled through the PLA specific approach ......................................... 313
Figure 5.7:
Impact indicators calculated for the glass refillable bottled water scenario by applying
the two different typologies of modelling approach described in paragraph 4.10.1..... 315
Figure 5.8:
Contribution of bottles and caps production and recycling processes to the CED
indicator for the glass refillable bottled water scenario modelled through the closed loop
and the hybrid approach............................................................................................ 315
Figure 5.9:
Impact indicators calculated for all the investigated scenarios (the dotted area in the tap
surface water bar specifies the contribution given by water transportation by car) ..... 318
Figure 5.10: Contribution of the major sub-processes to the CED and the global warming indicators
calculated for tap groundwater scenario .................................................................... 320
calculated for tap surface water scenario ...................................................................320
Figure 5.12: Comparison of the impact indicators calculated for the purification and the delivering of
1 m3 of groundwater and surface water..................................................................... 322
List of figures
13
Figure 5.13: Contributions of the major sub-processes to the CED and the global warming indicators
calculated for the treatment and the delivering of 1 m3 of groundwater ...................... 323
calculated for the treatment and the delivering of 1 m3 of surface water..................... 324
calculated for virgin PET one-way bottled water scenario ......................................... 326
calculated for PET refillable bottled water scenario................................................... 327
Figure 5.17: Contribution of the major sub-processes to CED and the global warming indicators
calculated for glass refillable bottled water scenario.................................................. 331
calculated for PLA to composting bottled water scenario .......................................... 333
calculated for PLA to incineration bottled water scenario .......................................... 334
Figure 5.20: Water consumptions calculated for the investigated scenarios (the dotted area in the tap
surface water bar specifies the contribution given by water transportation by car) ..... 337
Figure 5.21: Results of the sensitivity on the allocation of consumer purchasing trip burdens on the
CED and the global warming indicators in the comparison among the investigated
scenarios................................................................................................................... 340
Figure 5.22: Variation of the global warming indicator with the number of purchased items for the
one-way virgin PET bottled water scenario ............................................................... 342
Figure 5.23: Results of the sensitivity on dishwashing burdens on the CED and the global warming
indicators in the comparison among the investigated scenarios ..................................343
Figure 5.24: Results of the sensitivity on transport distance from public fountains to consumers
houses on the CED and the global warming indicators in the comparison among the
investigated scenarios (the dotted area in the tap surface water bar specifies the
contribution given by water transportation by car)..................................................... 346
Figure 5.25: Results of the sensitivity on the typology of reusable containers utilised in the surface
water scenario on the CED and the global warming indicators in the comparison among
the investigated scenarios.......................................................................................... 349
Figure 5.26: Results of the sensitivity on the transport distance from bottling plants to retailers or
local distributors on the CED and the global warming indicators in the comparison
among the investigated scenarios .............................................................................. 351
Figure 5.27: Results of the sensitivity on the number of uses of refillable bottles on the CED and the
global warming indicators in the comparison among the investigated scenarios ......... 355
Figure 5.28: Comparison among all the investigated scenarios of the upper and the lower bound
obtained for the CED and the global warming indicators on the basis of the variation of
the parameters considered during the sensitivity analysis .......................................... 358
14
List of figures
Figure D.1: Representation of the major upstream life cycle processes characterizing baseline
scenario 1 (utilisation of virgin PET one-way bottled water) ..................................... 390
scenario 2 (utilisation of recycled PET one-way bottled water) modelled through the
closed loop approach; the processes which differ from figure D.1 are represented in
grey .......................................................................................................................... 391
scenario 3 (utilisation of PLA one-way bottled water), the processes which differ from
figure D.1 are represented in grey ............................................................................. 392
Figure D.4: Representation of the major upstream life cycle processes characterizing waste
prevention scenario 1A (utilisation of purified groundwater from the tap) ................. 393
prevention scenario 1B (utilisation of purified surface water from public fountains) ..394
prevention scenario 2A (utilisation of refillable glass bottled water) modelled through
the closed loop approach........................................................................................... 395
prevention scenario 2B (utilisation of refillable PET bottled water), the processes which
differ from figure D.6 are represented in grey ........................................................... 396
Figure E.1: Contribution of the processes of preforms manufacturing and bottles recycling to global
warming, abiotic depletion and eutrophication impact indicators for the recycled PET
one way bottled water scenario modelled through the two different approaches
described in paragraph 4.6 ........................................................................................ 405
Figure E.2: Contribution of the PLA composting process to the abiotic depletion and eutrophicaiton
impact indicators for the PLA one way bottled water scenario...................................406
Figure E.3: Contribution by sub processes to the abiotic depletion and eutrophication impact
indicators for PLA composting modelled through the process specific approach........ 406
Figure E.4: Contribution by sub processes to the abiotic depletion and eutrophication impact
indicators for PLA composting modelled through the PLA specific approach............ 406
Figure E.5: Contribution of the major sub-processes to the abiotic depletion and the eutrophication
impact indicators calculated for tap groundwater scenario ......................................... 407
impact indicators calculated for tap surface water scenario........................................ 407
Figure E.7: Contributions of the major sub-processes to the abiotic depletion and the eutrophication
impact indicators calculated for the treatment and the delivering of 1 m3 of
groundwater.............................................................................................................. 408
impact indicators calculated for the treatment and the delivering of 1 m3 of surface
water. ....................................................................................................................... 409
List of figures
15
impact indicators calculated for virgin PET one way bottled water scenario .............. 410
impact indicators calculated for PET refillable bottled water scenario ....................... 411
impact indicators calculated for glass refillable bottled water scenario....................... 412
Figure E.12: Contribution of the major sub-processes to the CED and the global warming indicators
calculated for recycled PET bottled water scenario.................................................... 413
impact indicators calculated for recycled PET bottled water scenario ........................ 414
impact indicators calculated for PLA to composting bottled water scenario ............... 415
impact indicators calculated for PLA to incineration bottled water scenario............... 416
Figure E.16: Results of the sensitivity on the allocation of consumer purchasing trip burdens on the
abiotic depletion and the eutrophication impact indicators in the comparison among the
investigated scenarios ............................................................................................... 417
Figure E.17: Results of the sensitivity on dishwashing burdens on the abiotic depletion and the
eutrophication impact indicators in the comparison among the investigated
scenarios................................................................................................................... 418
Figure E.18: Results of the sensitivity on transport distance from public fountains to consumers
houses on the abiotic depletion and the eutrophication impact indicators in the
comparison among the investigated scenarios (the dotted area in the tap surface water
bar specifies the contribution given by water transportation by car)........................... 419
Figure E.19: Results of the sensitivity on the typology of reusable containers utilised in the surface
water scenario on the abiotic depletion and the eutrophication impact indicators in the
comparison among the investigated scenarios ........................................................... 420
Figure E.20: Results of the sensitivity on the transport distance from bottling plants to retailers or
local distributors on the abiotic depletion and the eutrophication impact indicators in the
comparison among the investigated scenarios ........................................................... 421
Figure E.21: Results of the sensitivity on the number of uses of refillable bottles on the abiotic
depletion and the eutrophication impact indicators in the comparison among the
investigated scenarios ............................................................................................... 422
Figure E.22: Comparison among all the investigated scenarios of the upper and the lower bound
obtained for the abiotic depletion and the eutrophication impact indicators on the basis
of the variation of the parameters considered during the sensitivity analysis .............. 423
16
List of figures
List of tables
Table S.1: Major features of the scenarios analysed in the present study .........................................40
Table S.2: Parameters considered in the sensitivity analysis and respective combination for the
definition of the upper and the lower bound of the impacts associated with all the
investigated scenarios....................................................................................................43
Table S.3: Amount of waste generated in all the investigated scenarios ..........................................43
Table 1.1: Possible criteria for the classification of waste prevention activities according to Salhofer
et al. (2008)...................................................................................................................60
Table 1.2: Examples of waste prevention activities classified according to the criteria proposed by
Cleary (2010b) ..............................................................................................................62
Table 1.3: Prevention potentials estimated by ACR+ (2010) for individualized waste prevention
activities........................................................................................................................69
Table 1.4: Prevention potentials calculated by Salhofer et al. (2008) for some municipal solid waste
prevention activities applicable to the city of Vienna .....................................................70
Table 1.5: Review of the most important municipal solid waste prevention measures and activities
on the basis of different sources (ACR+, 2010; European Commission, 2010;
Federambiente, 2010; Regione Lombardia, 2009; Regione Piemonte, 2009; Sahlofer et
al., 2008).......................................................................................................................72
Table 1.6: Consumptions of bottled water per typology of packaging in Italy for the year 2008
(Elaboration on data from Bevitalia (2009))...................................................................80
Table 2.1: Major features of the LCA models discussed in this chapter ........................................ 110
Table 3.1: Major streams of municipal waste collected in the Lombardia Region during the year
2007 (ISPRA, 2008)....................................................................................................113
Table 3.2: Amount of source separated fractions collected in the Lombardia Region during the year
2007 (ISPRA, 2008).................................................................................................... 113
Table 3.3: Composition of the input waste to the Silla 2 waste to energy plant and relative calculated
amount of each unsorted residual waste fraction assumed to be produced in Lombardia
during the year 2007.................................................................................................... 114
Table 3.4: Combination criteria of source separated and residual waste fractions used to define the
overall production of each waste fraction and the resulting gross waste composition for the
Lombardia Region for the year 2007 ............................................................................ 115
18
List of tables
Table 3.5: Total produced amount of each waste fraction and relative gross waste composition
assumed as reference for the Lombardia Region for the year 2007 and employed for the
purposes of this study..................................................................................................115
Table 3.6: Composition of the whole amount of plastic packaging waste sent to recovery by the
Corepla circuit for the year 2007 (Corepla, 2008) ........................................................ 116
Table 3.7: Amount of plastic materials assumed to be produced as waste in Lombardia Region
during the year 2007.................................................................................................... 117
Table 3.8: Volume of packaged water consumed in Italy during the year 2008 by typology of
packaging, both in absolute and specific terms (Elaboration on data from Bevitalia
(2009))........................................................................................................................ 117
Table 3.9: Average masses of PET bottles employed in Italy for water delivering (Federambiente,
2010) .......................................................................................................................... 118
Table 3.10: Definition of the total amount of PET bottles into the plastic waste stream .................. 118
Table 3.11: Definitive amount of each plastic waste fraction assumed to be produced in Lombardia
during 2007 and to enter the waste management system in the baseline scenario.......... 119
Table 3.12: Separated collection efficiencies considered for the plastic materials constituting the
waste flow................................................................................................................... 120
Table 3.13: Energy consumptions for the plastic selection process (Rigamonti and Grosso, 2009)..120
Table 3.14: Recovery efficiencies considered for the recovery processes of the plastic materials
constituting the waste flow .......................................................................................... 121
Table 3.15: Energy and materials consumptions for PET, HDPE and POF mix recovery processes 121
Table 3.16: Average elemental composition considered for plastic (Rigamonti, 2007).................... 124
Table 3.17: Assumed pollutant stack concentrations and calculated emission factors for the WTE
plant............................................................................................................................ 125
Table 3.18: Reagents consumption for flue gas cleaning ................................................................ 126
Table 3.19: Materials and energy inputs and outputs to and from the under-sift inactivation
process........................................................................................................................ 127
Table 3.20: Materials consumptions for fly ashes inactivation ........................................................ 127
Table 3.21: Materials and energy inputs and outputs to and from the Neutrec APCR recovery
process .............................................................................................................128
Table 3.22: Summary of energy and material outputs from the incineration process........................ 129
Table 3.23: Summary of process specific energy and material inputs to the incineration treatment1129
Table 3.24: Amount of each waste fraction entering the waste management system in the baseline
scenario....................................................................................................................... 131
Table 3.25: Amount of each waste fraction entering the waste management system in the waste
prevention scenario ..................................................................................................... 135
List of tables
19
Table 3.26: Global warming impact indicator calculated through the WasteMAP LCA model for each
sub-system that contribute to define the overall impact of the waste prevention scenario
and for the waste prevention scenario itself..................................................................138
Table 3.27: Global warming indicator calculated through the Waste MAP LCA model for each
analysed scenario and relative difference ..................................................................... 138
Table 3.28: Contribution of main processes to the global warming impact indicator calculated through
the WasteMAP LCA model for each sub-system and for the baseline scenario............. 139
Table 3.29: Global warming impact indicator calculated through the ISWP model for each analysed
scenario and contribution of the main processes to its definition ..................................144
Table 3.30: Global warming impact indicator calculated through the SSWP model for each analysed
Table 3.31: Major features of the LCA models discussed in this chapter ........................................ 152
Table 3.32: Comparison among the global warming impact indicator calculated through the
investigated models for all the examined scenarios ...................................................... 153
Table 3.33: Global warming impact indicator calculated through the WasteMAP LCA model for each
sub-system that contribute to define the overall impact of the waste prevention scenario
and of the waste prevention scenario itself...................................................................156
Table 3.34: Global warming indicator calculated through the WasteMAP LCA model for each
analysed scenario and relative difference ..................................................................... 157
Table 3.35: Contribution of main processes to the global warming impact indicator calculated through
the WasteMAP LCA model for each sub-system and for the baseline scenario............. 157
Table 3.36: Global warming impact indicator calculated through the ISWP model for each analysed
Table 3.37: Global warming impact indicator calculated through the SSWP model for each analysed
Table 3.38: Comparison among the global warming indicator calculated through the investigated
models for all the considered scenario variants ............................................................ 160
Table 4.1: Major features of the scenarios analysed in this chapter ............................................... 164
Table 4.2: Characterization factors (ADP) for some substances that contribute to the abiotic
resources depletion impact indicator so as reported in the CML 2001 baseline method
implemented in SimaPro ............................................................................................. 167
Table 4.3: Characterization factors (GWP100) for some substances that contribute to the global
warming impact indicator so as reported in the CML 2001 baseline method implemented
in SimaPro. ................................................................................................................. 168
Table 4.4: Characterization factors (EP) for the substances contributing to the eutrophication impact
indicator so as reported in the CML 2001 baseline method implemented in SimaPro ...170
20
List of tables
Table 4.5: Volume of packaged water consumed in Italy during the year 2008 by typology of
packaging, both in absolute and specific terms (Elaboration on data from Bevitalia
(2009))........................................................................................................................ 171
Table 4.6: Average masses of PET bottled water primary and secondary packaging materials
(Federambiente, 2010).................................................................................................172
Table 4.7: Amount of packaging waste generated by the consumption of one-way PET bottled water
in baseline scenario 1 ..................................................................................................172
Table 4.8: Elemental composition of paper .................................................................................. 174
Table 4.9: Summary of waste specific material and energy inputs and outputs of the paper
incineration process..................................................................................................... 174
Table 4.10: Average masses of PET bottled water primary packaging materials (Federambiente,
2010) .......................................................................................................................... 181
Table 4.11: Primary packaging materials masses expressed with respect to the reference flow for
baseline scenario 1 ...................................................................................................... 181
Table 4.12: Average masses of PET bottled water secondary packaging materials .......................... 185
Table 4.13: Secondary packaging materials masses expressed with respect to the reference flow for
baseline scenario 1 ...................................................................................................... 185
Table 4.14: Average masses of PET bottled water tertiary packaging materials............................... 187
Table 4.15: Tertiary packaging materials masses expressed with respect to the reference flow for
baseline scenario 1. ..................................................................................................... 188
Table 4.16: Materials employed for pallet manufacturing (Kellenberger et al., 2007)...................... 189
Table 4.17: Consumptions of lubricating oil and detergents for bottling plant operations ................ 192
Table 4.18: Waterborne emissions associated with filler machines washing, leaving the bottling plant
and released to the environment................................................................................... 194
Table 4.19: Major burdens associated with filler machines washing process and respective modules
utilised for their modelling and to create the module Filler machines washings in
SimaPro ...................................................................................................................... 195
Table 4.20: Processes associated with the life cycle of mineral oil and respective Ecoinvent modules
utilised to create the module Lubricating oil-life cycle in SimaPro............................... 196
Table 4.21: Calculation of transported masses in relation to the reference flow .............................. 197
Table 4.22: Mass and energy balances of the composting process nearby San Damiano D’asti plant
(Adaptation from Punzi (2009))................................................................................... 209
Table 4.23: Airborne emissions attributed to the composting process (Adaptation from Punzi
(2009))........................................................................................................................ 209
Table 4.24: Products substituted by the application of compost (Adaptation from Punzi (2009)) .... 210
Table 4.25: Elemental composition and lower heating value of PLA (NatureWorks, 2010b)........... 211
Table 4.26: Process specific burdens attributed to PLA composting and calculated CO2 emissions and
leachate production ..................................................................................................... 212
List of tables
21
Table 4.27: Summary of waste specific material and energy inputs and outputs of the PLA
incineration process..................................................................................................... 213
Table 4.28: Main features and typologies of treatments carried out at the various treatment stations at
the service of the aqueduct of Milan ............................................................................ 220
Table 4.29: Major inputs and outputs to and from the exhausted activated carbon reactivation process
at SICAV S.r.l. for the period 2004 - June 2009 (SICAV, 2009) ..................................229
Table 4.30: Amount of exhausted activated carbon sent to the reactivation process at SICAV S.r.l.
during the period 2004 – June 2009 (SICAV, 2009) .................................................... 229
Table 4.31: Airborne emissions originating from the exhausted activated carbon reactivation process
at SICAV S.r.l. during the period 2004 – June 2009 (SICAV, 2009) ............................ 230
Table 4.32: Energy and raw material consumptions involved in drinking water treatment and
delivering to the city of Milan ..................................................................................... 232
Table 4.33: Lengths and masses of steel pipes subdivided by diameters interval............................. 234
Table 4.34: Schematization of steel pipes average linear mass calculation for each diameters
interval........................................................................................................................ 234
Table 4.35: Schematization of cast iron pipes average linear mass calculation for each diameters
interval........................................................................................................................ 235
Table 4.36: Lengths and masses of cast iron pipes subdivided by diameters interval....................... 236
Table 4.37: Specific masses of pipes manufacturing materials attributed to the system ................... 238
Table 4.38: Specific masses of activated carbon filters and aeration towers manufacturing materials
attributed to the tap groundwater system...................................................................... 239
Table 4.39: Technical features of domestic depurators and estimated energy and material
consumptions employed in this study .......................................................................... 241
Table 4.40: Major features of the SimaPro module which models the process of domestic depuration
of water....................................................................................................................... 242
Table 4.41: Average energy and raw material consumptions of Energy Star classified dishwasher
considered in this study ............................................................................................... 243
Table 4.42: Consumptions of reagents for chlorine dioxide generation at the Anconella plant ........ 254
Table 4.43: Raw materials and energy consumptions attributed to the sodium chlorite manufacturing
process and employed to create the module “Sodium chlorite, 25% m/m solution, at
plant” .......................................................................................................................... 256
Table 4.44: Raw materials and energy consumptions associated with the integrated manufacturing
process of chlorine dioxide and employed to create the module “Chlorine dioxide, from
integrated process, at plant”......................................................................................... 261
Table 4.45: Raw materials and energy consumptions associated with PACl solution manufacturing
and employed to create the module “Polyaluminium chloride, 18% Al2O3 solution, at
plant” .......................................................................................................................... 266
Table 4.46: Raw materials associated with 10% Al2O3 PACl solutions production and employed to
create the module “Polyaluminium chloride, 10% Al2O3 solution, at plant” ................ 267
22
List of tables
Table 4.47: Major energy and materials inputs and outputs to and from the Anconella drinking water
treatment plant ............................................................................................................ 274
Table 4.48: Major consumptions and processes associated with the delivering of improved quality
water through the H2O plus system from public fountains ........................................... 277
Table 4.49: Primary packaging materials masses and amount of waste generated by the utilisation of
refillable glass bottles..................................................................................................282
Table 4.50: Energy consumptions of glass selection and recovery processes (Rigamonti and Grosso,
2009) .......................................................................................................................... 283
Table 4.51: Energy consumptions of steel selection and recovery processes (Rigamonti and Grosso,
2009) .......................................................................................................................... 283
Table 4.52: Amount of primary packaging materials involved in the delivering of refillable glass
bottled water ............................................................................................................... 290
Table 4.53: Amount of pallet materials involved in the delivering of refillable glass bottled
water........................................................................................................................... 293
Table 4.54: Consumptions of caustic soda and detergents employed for bottles washing ................ 296
Table 4.55: Waterborne emissions from the bottling plant and to the environment associated with
bottles washing ........................................................................................................... 297
Table 4.56: Specifications of the packaging system for 1 litre refillable PET bottled water............. 301
Table 4.57: Amount of waste generated by the consumption of refillable PET bottled water .......... 301
Table 4.58: Amount of primary packaging materials involved in the delivering of refillable PET
bottled water ............................................................................................................... 303
Table 4.59: Values employed for the inventory of the injection stretch-blow moulding process ...... 304
Table 4.60: Amount of pallet materials involved in the delivering of refillable PET bottled water ..305
Table 5.1: Amount of waste generated in all the investigated scenarios ........................................ 316
Table 5.2: Results of the sensitivity on the allocation of consumer purchasing trip burdens on the
CED and the global warming indicators for the interested scenarios............................. 341
Table 5.3: Results of the sensitivity on dishwashing burdens on the CED and the global warming
indicators for the tap groundwater scenario..................................................................343
Table 5.4: Results of the sensitivity on transport distance from public fountains to consumers houses
on the CED and the global warming indicators for the tap surface water scenario ........ 346
Table 5.5: Results of the sensitivity on the typology of reusable containers utilised in the surface
water scenario on the CED and the global warming indicators for tap surface water
scenario....................................................................................................................... 349
Table 5.6: Results of the sensitivity on the transport distance from bottling plants to retailers or local
distributors on the CED and the global warming indicators for the interested
scenarios ..................................................................................................................... 352
Table 5.7: Number of refillable bottles uses considered in various sources ...................................354
List of tables
23
Table 5.8: Results of the sensitivity on the number of uses of refillable bottles on the CED and the
global warming indicators for refillable bottled water scenarios ...................................356
Table 5.9: Combination of sensitivity parameters for the definition of the upper and the lower bound
of the impacts associated with all the investigated systems .......................................... 357
Table 5.10: Comparison among all the investigated scenarios of the upper and the lower bound
obtained for the CED and the global warming indicators on the basis of the variation of
the parameters considered during the sensitivity analysis ............................................. 359
Table A.1: Main Italian packaged mineral water producer groups and brands for the year 2008
(Bevitalia, 2009) ......................................................................................................... 379
Table A.2: Calculated distance from Milan of bottling plants belonging to main Italian packaged
mineral water producer groups .................................................................................... 380
Table A.3: Masses of 1 litre glass bottles of main Italian mineral water brands (Provided by personal
communication with the companies)............................................................................ 381
Table B.1: Airborne emissions calculated for paper and PLA incineration processes..................... 383
Table C.1: Components of the alkaline detergent employed for daily filler machine washing and
respective modelling ...................................................................................................385
Table C.2: Components of the acid detergent employed for daily filler machine washing and
Table C.3: Components of the foaming disinfectant employed for daily filler machine washing and
Table C.4: Components of the caustic detergent employed for weekly filler machine washing and
Table C.5: Components of the not-foaming disinfectant employed for weekly filler machine washing
and respective modelling............................................................................................. 386
Table C.6: Components of the descaling agent employed for bottles washing and respective
modelling.................................................................................................................... 387
Table C.7: Components of the defoaming agent employed for bottles washing and respective
modelling.................................................................................................................... 387
Table C.8: Components of the sequestering agent employed for bottles washing and respective
modelling.................................................................................................................... 387
Table D.1: Major upstream life cycle processes characterizing baseline scenario 1 (utilisation of
virgin PET one-way bottled water) .............................................................................. 397
24
List of tables
Table D.2: Major upstream life cycle processes characterizing baseline scenario 2 (utilisation of
recycled PET one-way bottled water, modelled through the closed loop approach) which
differ from baseline scenario 1 .................................................................................... 398
Table D.3: Major upstream life cycle processes characterizing baseline scenario 3 (utilisation of PLA
one-way bottled water) which differ from baseline scenario 1...................................... 398
Table D.4: Major upstream life cycle processes characterizing waste prevention scenario 1A
(utilisation of purified groundwater from the tap) ........................................................ 399
Table D.5: Major upstream life cycle processes characterizing waste prevention scenario 1B
(utilisation of purified surface water from public fountains)......................................... 400
Table D.6: Major upstream life cycle processes characterizing waste prevention scenario 2A
(utilisation of refillable glass bottled water), modelled through the closed loop
approach ..................................................................................................................... 401
Table D.7: Major upstream life cycle processes characterizing waste prevention scenario 2B
(utilisation of refillable PET bottled water)..................................................................403
Table E.1: Life cycle impacts of the domestic depuration treatment.............................................. 424
Table E.2: Life cycle impacts of the public treatment of water quality improvement. .................... 424
Table E.3: Life cycle impacts of secondary packaging materials employed in the various analysed
systems ....................................................................................................................... 425
Table E.4: Life cycle impacts of transport packaging materials employed in the various analysed
systems ....................................................................................................................... 425
Table E.5: Life cycle impacts of caps employed in the various analysed systems .......................... 425
Table E.6: Contributions by sub-processes to the overall impacts of bottling plant operations ....... 425
Table E.7: Results of the sensitivity on the allocation of consumer purchasing trip burdens on the
abiotic depletion and the eutrophication impact indicators for the interested
scenarios. .................................................................................................................... 426
Table E.8: Results of the sensitivity on dishwashing burdens on the abiotic depletion and the
eutrophication impact indicators for the tap groundwater scenario ............................... 426
Table E.9: Results of the sensitivity on transport distance from public fountains to consumers houses
on the abiotic depletion and the eutrophication impact indicators for the tap surface water
scenario....................................................................................................................... 426
Table E.10: Results of the sensitivity on the typology of reusable containers utilised in the surface
water scenario on the abiotic depletion and the eutrophication impact indicators for the
tap surface water scenario............................................................................................ 427
Table E.11: Results of the sensitivity on the transport distance from bottling plants to retailers or local
distributors on the abiotic depletion and the eutrophication impact indicators for the
interested scenarios ..................................................................................................... 427
List of tables
25
Table E.12: Results of the sensitivity on the number of uses of refillable bottles on the abiotic
depletion and the eutrophication impact indicators for refillable bottled water
scenarios ..................................................................................................................... 427
Table E.13: Comparison among all the investigated scenarios of the upper and the lower
bound obtained for the abiotic depletion and the eutrophication impact indicators
on the basis of the variation of the parameters considered during the sensitivity
analysis ...................................................................................................................... 428
26
List of tables
Abstracts
Waste prevention holds a primary role in the European waste management strategy. Role that
is particularly reinforced within the recent Waste Framework Directive (2008/98/EC) which,
for the first time, urges Member States to establish waste prevention programmes. In such a
context it is recognized how, in order to evaluate the actual environmental sustainability of a
prevention activity, a life cycle perspective should be employed. This allows to go beyond the
simple reduction of the generated waste which, alone, does not automatically imply to achieve
sustainability.
In this study a research was therefore carried out about which methodological aspects of
traditional life cycle assessment (LCA) applied to solid waste management systems should be
adjusted to account for prevention activities. In particular, by modifying conventional
functional unit and system boundaries, two conceptual LCA models are proposed and their
practical applicability is compared through the analysis of a simplified case study.
One model is then applied to the thorough analysis of two prevention activities consisting,
respectively, in the use of public network water and of a refilling system for drinking
purposes, instead of one-way bottled water. Three baseline scenarios characterized,
respectively, by the utilisation of virgin polyethylene terephthalate (PET), of recycled PET
and of polylactic acid (PLA) one-way bottled water are considered as terms of comparison.
One energetic indicator and three environmental impact indicators are analysed in the study,
leading to a complex evaluation of results. In typical conditions, the utilisation of public
network water directly from the tap results to be the best performing option, while if water is
withdrawn from public fountains, its transportation by private car can give significant
impacts. Refilling scenarios are found to be characterized by performances dependent from
transport distances. For the same distances the utilisation of refillable PET bottles appears to
be the most preferable option for packaged water delivering, while the use of refillable glass
bottles is characterized by performances comparable with those of one-way bottled water.
28
Abstracts
La strategia europea di gestione dei rifiuti assegna un ruolo primario alla loro prevenzione.
Tale ruolo è stato particolarmente rafforzato nella recente Direttiva Quadro sui Rifiuti
(2008/98/CE) che, per la prima volta, sollecita gli Stati Membri ad elaborare programmi di
prevenzione. In tale contesto si riconosce come, al fine di valutare la reale sostenibilità
ambientale di un’azione preventiva, sia necessario adottare una prospettiva di ciclo di vita che
permetta di andare oltre la semplice riduzione del rifiuto prodotto che, di per sé, non
garantisce automaticamente l’effettivo raggiungimento di tale sostenibilità.
In questo studio si sono individuati quali aspetti metodologici dell’analisi del ciclo di vita
(LCA) applicata alla gestione dei rifiuti urbani devono essere modificati per poter includere in
essa le attività di prevenzione. In particolare, modificando l’unità funzionale e i confini del
sistema convenzionalmente adottati, sono stati proposti due modelli concettuali di LCA e la
loro applicabilità pratica è stata confrontata mediante l’analisi di un caso di studio
semplificato.
Uno dei modelli è stato poi applicato all’analisi approfondita di due attività preventive che
consistono, rispettivamente, nel bere acqua di rete pubblica oppure confezionata in bottiglie
riutilizzabili (a rendere), anziché monouso. Tre scenari base caratterizzati, rispettivamente,
dall’utilizzo di contenitori in polietilene tereftalato vergine (PET), in PET riciclato per il 50%
e in acido polilattico sono stati considerati come termine di paragone.
Sono stati analizzati un indicatore energetico e tre indicatori di impatto ambientale, da cui è
emerso un complesso quadro di risultati. In condizioni tipiche l’utilizzo dell’acqua di rete
pubblica direttamente dal rubinetto è risultata l’opzione migliore, mentre se prelevata da
fontanelli pubblici, il suo successivo trasporto con auto privata può causare impatti
significativi. L’utilizzo di contenitori a rendere risulta invece caratterizzato da prestazioni
dipendenti dalle distanze di trasporto in gioco. A parità di distanza l’utilizzo di bottiglie a
rendere in PET sembra essere l’opzione preferibile per la distribuzione di acqua confezionata,
mentre l’uso di bottiglie a rendere in vetro comporta impatti confrontabili con quelli causati
dall’utilizzo di contenitori monouso.
30
Abstracts
Executive summary
Waste prevention has long been pointed out by the European legislation as the primary
objective to be pursued by any waste management oriented policy and strategy. Its role is
particularly reinforced by the last Waste Framework Directive 2008/98/EC (European
Parliament and Council, 2008) which, embodying the request of the Thematic Strategy on the
prevention and recycling of waste (Commission of the European Communities, 2005), for the
first time urges Member States to establish waste prevention programmes in which waste
reduction objectives are set out and the measures for their achievement identified. Such
objectives and measures should be aimed at minimising the environmental impacts of the use
of resources throughout their whole life cycle and not only when they become waste.
According to the definition given in the Directive, preventive measures strictly take place
before a product has become waste and include a quantitative aspect (if aim at reducing the
amount of generated waste) and a qualitative aspect (if aim at reducing the adverse impacts of
the generated waste and the content of harmful substances in materials and products). Re-use
and life span extension of products are considered to be preventive measures as well.
With regard to the quantitative aspect, a useful, general classification of prevention activities
is the one proposed by Cleary (2010b), according to which they can be distinguished between
those based on dematerialization and those based on reduced consumptions. The former
consist in reducing waste generation by totally or partially substituting the service provided
by a certain product system (target product system) with that provided by a less waste
generating one (alternative product system), without affecting the magnitude of the service
supplied. The latter instead consist in the sole reduction of the consumption of the service
provided by a certain waste generating product system. Product re-use is considered to be a
form of dematerialization.
Following this classification it is possible to recognize how, if the environmental benefits of
decrease waste generation are evident when it is achieved through activities involving reduced
consumption, or activities assimilable to this principle, they are instead not assured when
prevention takes place through dematerialization. In the first case the potential impacts
associated with all possible upstream and downstream activities included in the life cycle of a
32
Executive summary
resource are indeed avoided, while in the second case additional upstream and downstream
impacts are involved, that have to be carefully evaluated.
We have therefore also recognized how a life cycle perspective should be generally employed
to evaluate the actual environmental effects of undertaking a prevention activity, in order to
go beyond the mere reduction of the generated waste which, alone, does not automatically
imply to achieve environmental sustainability.
One of the most important quantitative based tool employable to support this perspective is
the life cycle assessment (LCA), which aims at linking the major material and energy inputs
and outputs of the whole life cycle of a product or service, with quantified potential
environmental impacts.
In particular, by considering that the above mentioned Directive requires the drafting of waste
prevention programmes that can be integrated within conventional waste management plans,
we have furthermore recognized the importance of the availability for waste managers of a
unique LCA tool capable to evaluate the validity of a waste management scheme which,
besides traditional waste treatment options, includes prevention activities.
In this study a research was therefore carried out concerning which methodological aspects of
traditional waste management oriented LCA should be adjusted to account for prevention
activities.
The major limitations of traditional waste management oriented LCA are represented by the
utilisation of a constant mass based functional unit (i.e the management of 1 tonne of waste
with a given composition) and by the definition of system boundaries generally based on the
‘zero burdens’ assumption, which consists in the exclusion from the analysis of those
activities belonging to all life cycle stages occurring upstream the moment in which products
become wastes. These activities can indeed be considered as common to all the scenarios to
be compared since, thanks to the use of a functional unit defined as above, the same amount
of waste is generated in such scenarios.
By modifying conventional functional unit and system boundaries, two conceptual waste
management oriented LCA models are therefore proposed, also in the attempt to simplify the
applicability of the WasteMAP LCA model presented in Cleary (2010b) to address the issue
of integrating prevention activities within traditional waste management oriented LCA.
Executive summary
33
In the first model, developed by also taking suggestion from the work of Gallo (2009), waste
prevention is considered, from a conceptual point of view, to be part of the service provided
by the waste management system in which it can or can not be included.
The functional unit is hence defined as:
“the integrated management of the annual amount of waste potentially produced in a given
geographical area (or by one its inhabitant), in which waste prevention activities are
undertaken”.
In this way the amount of potentially generated waste to be managed through prevention and
conventional treatments is the same in all the possible considered scenarios and their
comparison is allowed since they are based on the same functional unit.
Waste prevention is then considered to be a waste management option that avoids all the
processes associated with the upstream life cycle of the prevented waste or, in other words,
the supplying of a service through the target product system(s) and the occurring of the
respective upstream life cycle processes and, contemporarily, in the case in which prevention
takes place through dematerialization, it implies the supplying of the same amount of service
through the alternative product system(s) and the occurring of the respective upstream life
cycle processes. When analysing a preventive scenario, traditional system boundaries of
waste management oriented LCA are therefore expanded to include these upstream processes
(figure S.1), partially abandoning the ‘zero burdens’ assumption which, in general, is no
longer valid since different amounts of waste are generated in the scenarios to be compared.
For the practical impacts calculation, the avoided burdens associated with the avoided
upstream life cycle processes of the prevented waste are credited to the preventive waste
management system, while those associated with the possible alternative product system are
charged to the system itself. These lasts would not be included if waste prevention took place
through reduced consumption. The procedures for the calculation of the impacts of a not
preventive (baseline) and a waste prevention scenario are graphically illustrated in figure S.1.
The model is named as Integrated Scenarios Waste Prevention Model (ISWPM), since both
the product systems interested by waste prevention are considered at the level of the
preventive scenario, even if the target product system(s) rather belongs to the not preventive
scenario.
Being based on the concept of avoided and additional burdens, the model does not allow the
accounting of the absolute impacts associated with a given scenario, but it can be only used
for the differential comparison of the impacts of a preventive and a not preventive scenario.
34
Executive summary
ISWPM
BASELINE SCENARIO
Potentially generated municipal solid waste = Input waste
REFERENCE (REF) WMS
Conventional waste
management processes
(i.e. incineration)
Domestic treatments
(i.e. home composting)
Compensative processes
(i.e. energy generation)
Traditional system boundaries
VS
WASTE PREVENTION SCENARIO
Avoided upstream life
cycle processes of the
target product system(s)
(UpTPS1,n)
Additional upstream life
alternative product system(s)
(UpAPS1,n)
Potentially generated municipal solid waste > Input waste
PREVENTIVE (PREV) WMS
Conventional waste
(i.e. incineration)
Domestic treatments
Expanded system boundaries
IMPACT CALCULATIONS
BASELINE SCENARIO
REF WMS
VS
n
n
PREV WMS   UpTPS i   UpAPS i
i 1
i 1
Figure S.1: Simplified representation of the system boundaries considered by the Integrated scenarios waste
prevention model for a baseline and a waste prevention scenario including prevention activities taking place
through dematerialization and procedures for the calculation of the respective impacts
Executive summary
35
In order to allow the separation of the burdens/impacts pertaining to a preventive and to a not
preventive scenario, a second model is also finally proposed and named, for this reason, as
Separate Scenario Waste Prevention Model (SSWPM).
To this end, according to the suggestion of Ekvall (2007), the functional unit is defined as:
“the management of the annual amount of waste produced in a given geographical area (or
by one its inhabitant)”.
This amount varies according to the scenario as a consequence of the introduction of
prevention activities, but the comparison among scenarios dealing with different amounts of
waste is now allowed since this is not a mass based functional unit. In this case there is no
need to consider waste prevention as part of the service provided by the integrated waste
management system, even if actually it is.
A direct consequence of the choice of such a functional unit is the no longer general validity
of the zero burdens assumption because different amounts of waste enter in different
scenarios to be compared and the system boundaries should be therefore expanded to include
at least those upstream life cycle processes which differ among the scenarios for their
typology or magnitude. Such processes are those belonging to the target product system(s) for
not preventive scenarios and those of the alternative product system(s) for preventive
scenarios (these lasts would not be included if prevention took place through reduced
consumption).
In this way the potential benefits and loads associated with the implementation of a
prevention activity are automatically accounted for when a preventive and a not preventive
(baseline) scenario are compared. A representation of the processes to be included in the
system boundaries for both the mentioned scenarios, as well as the procedures for the
calculation of the respective impacts are reported in figure S.2.
Contrary to the previous model (ISWPM), the present one does not foresee to assign any
credits to the preventive scenario but it aims at considering the different upstream processes in
the scenario in which they actually occur. For this reason, other than for the differential
comparison of scenarios, it can also be employed for the accounting of the impacts associated
with a given scenario.
36
Executive summary
BASELINE SCENARIO
SSWPM
Upstream life cycle processes
of the target product system(s)
(UpTPS1,n)
Generation of municipal solid waste
REFERENCE (REF) WMS
Conventional waste
(i.e. incineration)
Domestic treatments
VS
Upstream life cycle processes of
the alternative product system(s)
(UpAPS1,n)
Conventional waste
(i.e. incineration)
Domestic treatments
IMPACT CALCULATIONS
BASELINE SCENARIO
n
REF WMS   UpTPS i
i 1
VS
n
PREV WMS   UpAPS i
i 1
Figure S.2: Simplified representation of the system boundaries considered by the Separated scenarios waste
prevention model for a baseline and a waste prevention scenario including prevention activities taking place
through dematerialization and procedures for the calculation of the respective impacts
Executive summary
37
With regard to the WasteMAP LCA model (Cleary, 2010b), it is mainly conceived to deal
with prevention activities which take place through dematerialization. These are considered as
functionally equivalent to conventional waste treatment options since they do not affect the
magnitude of the service provided to the population and, on this basis, the functional
equivalence of preventive and not preventive scenarios is also ensured. Another consequence
of this functional equivalence is that the amount of (potentially generated) waste managed
through prevention activities added to that managed through conventional treatments is the
same for all the scenarios to be compared, and the effect of managing part of it through
prevention is just to avoid its generation. The system boundaries of traditional waste
management oriented LCA are therefore expanded to include those upstream life cycle
processes belonging to the target product system(s) and to the alternative product system(s),
since they differ among the scenarios to be compared, while the zero burdens assumption is
maintained for those product systems unaffected by waste prevention.
Being the systems to be compared multifunctional, since both the functions of managing a
given amount of (potentially) generated waste and of supplying the service(s) of the product
system(s) affected by waste prevention are performed, two functional units are employed by
the model to assure the functional equivalence among compared scenarios. The primary
functional unit assures that a fixed amount of (potentially generated) waste is managed under
each scenario, while the secondary functional unit assures the that the same level of service(s)
is supplied in each scenario, either by the target product system(s) or by the alternate product
system(s). According to the base variant of the model, for the calculation of the
burdens/impacts of a preventive scenario, the burdens/impacts associated with the upstream
life cycle processes of the target product system(s) are subtracted to those of the waste
management system which deals with the amount of waste still generated after the
implementation of prevention activities, while those of the alternative product system(s) are
added to them. An alternative procedure would consist in assigning the burdens/impacts of the
upstream life cycle processes of the target product system(s) to the not preventive (baseline)
waste management system, instead of subtracting them from the preventive waste
management system.
This model appears conceptually quite complex, probably in reason of the fact that the author
aims at proposing a model strongly rigorous and consistent with the ISO standards (ISO
2006a; 2006b).
38
Executive summary
Despite built up on the basis of different theoretical assumptions, the two proposed models as
well as the WasteMAP LCA model are expected to lead to the same results in differential
terms between a preventive and a not preventive (baseline) scenario, since they are based on
applying, in different manners, expansion of the system boundaries traditionally employed in
waste management oriented LCA, to account for the same upstream life cycle processes
(those of the product systems affected by waste prevention) and of the respective benefits and
loads.
This fact has been indeed confirmed by the outcomes of a simplified analysis carried out to
compare the practical applicability of the three mentioned models, through which it has also
been possible to recognize how, from a practical point of view, the utilization of the models
has been translated in implementing, in different ways, the same processes within the LCA
software (SimaPro) utilised as support for the analysis.
The WasteMAP LCA model is resulted to be the one of more complex applicability and the
major difficulty is expected to be associated with the need of defining a proper secondary
functional unit (as required by the model), operation that is probably not possible to perform
for several typologies of prevention activities. This relative complexity appears to be
associated with the fact that the model is conceived to be as much rigorous and ISOconsistent as possible, by aiming at assuring a strong functional equivalence among the
scenarios to be compared. Its utilisation is therefore suggested especially in those cases in
which a rigorous analysis has to be carried out, for which such a strong equivalence of
compared scenarios has to be assured.
Prevention activities taking place through reduced consumption can not be however compared
on a functionally equivalent basis with this model, even if the methodology to be applied for
impacts calculation can be utilised as well.
The SSWP model can be utilised when an accounting of the impacts of a given scenario needs
to be carried out, or if simply the effects of the product systems interested by prevention need
to be accounted for separately within the scenario in which they actually take place.
If one was instead interested in evaluating the net difference of the impacts of a preventive
scenario with respect to those of the respective not preventive waste treatment system, or if it
is simply preferred to work with a credits-based system, the ISWP model can be the best
alternative.
Executive summary
39
The SSWP model is then applied to the through analysis of two prevention activities that
could be undertaken to reduce the amount of waste generated by the consumption of drinking
water: the use of public network water and of a returning and refilling system instead of oneway bottled water.
These particular activities are explored since they are considered to be among the most
meaningful for the Italian context. Last available data show indeed how Italy sits at the first
place among European countries, and at the third in the world, with regard to the per capita
bottled water consumption (about 194 litres/inhabitant/year in 2008), the major part of which
(around 79%) takes place through the wasteful practice of utilising one way PET bottles
(Bevitalia, 2009; Martinelli, 2010).
Three baseline scenarios characterized, respectively, by the utilisation of virgin polyethylene
terephtalate (PET), of 50% recycled PET and of polylactic acid (PLA) one way bottled water
are firstly assessed, to be used as terms of comparison. The former is indeed representative of
the current situation, while the second and the third represent two possible evolutional
scenarios for the Italian context. These scenarios are compared with two public network water
preventive scenarios in which purified groundwater from the tap (real case of Milan) and
purified surface water from public fountains (real case of Florence) are respectively utilised.
Finally, two returning and refilling scenarios which foresee, respectively, the utilisation of
glass and of PET refillable bottled water, are considered. The most important features of the
analysed scenarios are reported in table S.1.
The overall goal of the analysis is to evaluate if and in which conditions the investigated
prevention activities, besides reducing waste generation, are actually associated with better
overall environmental performances with respect to the different options considered for the
use of one-way bottled water. The analysis is not aimed at discriminating any typology of
packaging system and all the results are strictly related to the assumptions performed during
the analysis and to the choices which are followed.
The functional unit, common to all scenarios, is assumed to be:
“the management of the amount of (municipal) waste annually generated from the
consumption of drinking water by one Italian citizen”.
This amount is subject to changes, according to the scenario, for a constant amount of
drinking water consumption, considered equal to around 152 litres per inhabitant per year.
40
Executive summary
The analysis is carried out with the support of the software SimaPro, widely employed to
perform LCAs of any kind of product and service.
Table S.1: Major features of the scenarios analysed in the present study
Scenarios and
subscenarios
Water delivering options
Baseline scenario 1
One-way virgin
PET bottled water
Baseline scenario 2
One-way 50% recycled
PET bottled water
Baseline scenario 3
One-way PLA
bottled water
Waste prevention
scenario 1A
Waste prevention
scenario 1B
Purified groundwater
from the tap
(real case of Milan)
Purified surface water
from public fountains
(real case of Florence)
Typology of
packaging
packaging mix
composed by
2, 1.5 and 0.5
litres bottles
End of life options
for bottles/containers
77% recycling
23% incineration
77% recycling
23% incineration
Two subscenarios:
1) 100% composting and,
2) 100% incineration
1 reusable glass jug
(Recycling)*
9 reusable 1 litre
glass bottles
(Recycling)*
Waste prevention
1 litre glass bottles
Refillable glass bottled water
100% recycling
scenario 2A
used for 10 times
Waste prevention
1 litre PET bottles
Refillable PET bottled water
100% recycling
scenario 2B
used for 15 times
(*) The burdens of the recycling processes of containers employed in public network water systems are assigned,
for simplicity, to the upstream product systems
One energetic indicator (cumulative energy demand, CED) and three environmental impact
indicators (global warming, abiotic resources depletion and eutrophication) are considered in
the analysis.
Not prevented waste fractions are excluded from the analysis in order to focus on the
performances of the different delivering options. The system boundaries include therefore the
only treatment processes of the waste generated by the different delivering options and,
according to the utilised model, they are further expanded to include all the upstream
processes pertaining to the life cycle of such options.
In particular for bottled water systems the process of primary, secondary and transport
packaging materials production, bottling plant operations, transportation to retailers or local
distributors and from these lasts to the consumers house are considered. The tap groundwater
system includes the processes associated with water purification and delivering, its quality
improvement at domestic level as well as the life cycle and washing of a reusable glass
container. Besides the processes of water purification, the tap surface water system includes
also those of water quality improvement at public level for its delivering from public
Executive summary
41
fountains, the life cycle of reusable glass bottles employed to conserve water and their
transportation from fountains to consumers house by car.
In order to model bottled water scenarios, and especially mass and energy flows of the
processes associated with bottling operations, the plant of a medium size bottling company
located in northern Italy was visited, and primary data concerning this reality were employed
to carry out the inventory. When the utilisation of data representative of more general
conditions (i.e. primary packaging material quantities or the number of uses of refillable
bottles) is preferable, the information provided by the examined company were integrated
with those obtained by other bottling companies or with data found in the literature. In
particular the features of the packaging system characterizing the PET refillable bottled water
scenario are totally defined on the basis of literature data concerning the German context
(country in which such a system is well established), because of the lack of such a practice in
Italy.
The tap groundwater system is modelled on the basis of the features and through the primary
data regarding the purification and delivering system which provides drinking water to the
municipality of Milan, while the domestic improving quality system is modelled on the basis
of real data regarding equipments based on the technology of the reverse osmosis, which is
expected to be the most energy intensive among the several available options aimed at this
purpose.
The tap surface water scenario models instead the purification and delivering system which
provides drinking water to the city of Florence and to its suburban area, which are entirely
supplied with water withdrawn from the Arno river and purified by the Anconella plant. In
this scenario, water quality is considered to be improved at public level and delivered from
public fountains, as actually happens it that area.
Life cycle data concerning materials production and energy generation are taken as much as
possible from the reliable Ecoinvent database. When they were not available, apposite
modules were designed on the basis of literature data concerning existing technologies (i.e.
for sodium chlorite production), or of primary data regarding existing production realities (i.e.
for polyaluminium chloride).
The life cycle of 50% recycled PET bottles is modelled in two different ways: through the
conventional closed loop approach and through a methodology termed as the hybrid
approach. This last consists in utilising an hybrid allocation procedure to deal with the
multifunctionality of recycling, based on applying the cut off approach for the upstream
42
Executive summary
process that provides recycled material for bottles manufacturing and the avoided burden
approach for the process belonging to the waste management system which handles post
consumer bottles. This approach is proposed in the attempt to maintain upstream and
downstream processes separated, and to allow the utilisation of the avoided burden approach
to model the recycling processes which take place in the waste management system as it is
conventionally done in traditional waste management oriented LCA.
Both mentioned approaches are also applied to the modelling of glass bottles and aluminium
caps life cycle in the refillable glass bottled water scenario.
Since the results obtained through the use of the closed loop approach assign the worst
performances to the mentioned scenarios, they are employed for the final comparison
according to a conservative approach.
Also PLA bottles composting is modelled according to two different approaches, the process
specific and the PLA specific one. They mainly differ for the fact that in the former, PLA is
considered to behave as a generic organic waste and all the process specific burdens
associated with a traditional composting process are directly assigned to PLA composting. In
the latter, PLA is instead assumed to be composted in the share of 30% with traditional
organic waste and its elemental composition is taken into account to define more waste
specific burdens as well as it is considered to be completely degraded during the process and
not to generate any meaningful amount of compost which would allow to avoid the
production of peat and fertilizers. The PLA specific approach results to be that assigning the
worst performances to the investigated scenario and therefore employed for the comparison.
Energy savings are recognized to potentially occur during PLA preforms and bottles
manufacturing but only rough estimate could have been performed.
A sensitivity analysis is performed on those parameters which are arbitrarily assumed during
the inventory and resulted or expected to have a meaningful influence on the outcomes, as
well as on those parameters subject to great variability. Table S.2 summarises the investigated
parameters, the respective values considered in the base inventory, and the way in which they
are combined in the attempt to define un upper and a lower bound of the impacts of each
scenario.
43
Executive summary
Table S.2: Parameters considered in the sensitivity analysis and respective combination for the definition of the
upper and the lower bound of the impacts associated with all the investigated scenarios
Tap water scenarios
Bottled water scenarios
Parameters/assumptions
Allocation factor of consumer
purchasing trip burdens
Distance from bottling plants to
retailers/local distributors
Scenarios
One way
bottled water
scenarios
Lower bound
Total
purchasing of
60 items
(1.67%)
Base case
Total
purchasing of
30 items
(3.33%)
Upper bound
40 km
300 km
800 km
Glass bottles:
50
PET bottles:
25
Washing
every 5 uses
as part of a
load of 50
items
Glass bottles:
10
PET bottles:
15
Washing
every 4 uses
as part of a
load of 30
items
2 km
5.5 km
10 km
6 PET bottles
by 1.5 litres
9 glass bottles
by 1 litre
-
All bottled
water scenarios
Number of uses for refillable
bottles
Refillable
bottled water
scenario
Allocation of dishwashing
burdens to the reusable glass jug
Tap
groundwater
scenario
Roundtrip distance from public
fountains to consumers houses
Typology of reusable containers
employed to conserve water
Tap surface
water scenario
Tap surface
water scenario
Purchasing of
only water
(100%)
-
Washing after
each use as
part of a load
of 15 items
Table S.3 reports instead, as a first term of comparison, the amount of municipal waste
generated in all compared scenarios. The amount of sludge produced during the purification
of surface water is also reported for completeness.
Table S.3: Amount of waste generated in all the investigated scenarios
1
One way BW
scenarios
Glass refillable
BW1 scenario
4.12
7.912
PET refillable
BW1 scenario
kg/inhabitant/year
1.442
TW1 scenario
(groundwater)
TW1 scenario
(surface water)
0.53
Sludge: 0.0265
Other: 0.00864
Total: 0.0355
3.3
Sludge: 0.174
Other: 0.0565
Total: 0.23
g/litre of delivered water
27
52
9.47
1: BW: Bottled Water; TW: Tap water.
2: The values reported include the contribution either of primary or of secondary packaging.
3: The value refers to the waste generated by the annual substitution of the activated carbon filter of the domestic
depurator. The amount of waste generated by the use of the glass jug is instead not reported because, other than
of negligible entity, it is a function of consumers behaviour rather than a specific feature of the scenario.
4: This value refers to the waste generated by the periodical substitution of consumable materials of the
depuration system utilised for water delivering from public fountains (polypropylene pre-filter and activated
carbon filter).
5: The amount of waste generated by the use of glass bottles is not reported because it is a function of consumers
behaviour rather than a specific feature of the scenario.
The utilisation of refillable PET bottles results to be the least waste generating packaged
water option and an actual prevention in term of mass is achieved with respect to one way
44
Executive summary
bottled water scenarios. On the other hand, the use of refillable glass bottles does not imply an
actual prevention in terms of mass of generated waste because of the higher density of glass
with respect to PET. In this case it is the number of items that eventually become waste that is
instead reduced.
The amount of waste generated in the two tap water scenarios results one order of magnitude
lower than the amount generated in all bottled water scenarios when it is expressed on annual
basis, even if the amount of sludge originating from the purification process of surface water
is considered. The contribution given by reusable containers (glass jug and bottles) employed
to conserve water should be also accounted for, but the respective amount appears to be a
function of consumers behaviour rather than a specific feature of the systems. However, if on
the one hand it can be assumed negligible in view of the long life span that generally
characterize these objects, on the other it is clear how their inefficient use could lead to an
increase of the amount of waste generated to levels comparable with bottled water scenarios.
Figure S.3 finally shows, as an example, the global warming impact indicator calculated for
all the analysed scenarios (coloured bars) and the respective upper and lower bounds (black
bars) resulting from the combination of the sensitivity parameters specified in table S.2. Its
profile is however very similar to those of the other analysed indicators. The dotted area of
the bar representing the tap surface water scenario specifies the contribution given by the
possible use of a private car for the transportation of water from public fountains to
consumers house.
45
Executive summary
Global warming
70
64.9
63.9
67.5
65.1
kg CO2 eq./F.U.
60
49.1
50
34.5
40
30
24.8
23.8
27.4
25.0
26.2
20.7
16.5
20
10
31.2
18.9
17.9
21.5
9.6
19.1
13.6
0
Virgin PET R-PET oneone-w ay
w ay
PLA onew ay
compost.
PLA onew ay incin.
GLASS
ref illable
8.2
9.2
3.8
2.1
PET ref illable
Tap
Tap surf ace
groundw ater w ater
1.5
Figure S.3: Global warming impact indicator calculated for all the analysed scenarios with the respective upper
and lower bounds resulting form the sensitivity analysis (the dotted area in the tap surface water bar specifies
the contribution given by water transportation by car)
By looking at figure S.3, a complex framework, characterized by a wide variability of the
impacts, emerges from the results, and confirms the need of adopting a life cycle perspective
to evaluate if a prevention activity is actually sustainable from an environmental point of
view. It is indeed impossible to identify a system preferable in all the potential conditions but
different factors actually concur to the definition of the performances of a given scenario.
Despite this variability, it is possible to recognize that in typical conditions the utilisation of
public network water directly from the tap (being it groundwater or surface water), beyond
reducing waste generation, results to be definitely the best performing option with respect to
all the considered indicators, even when water quality is improved by a further treatment at
domestic level. Only in the case in which very inefficient washing conditions, which are
expected to be very uncommon, are considered for the reusable container (dishwashing after
every use as part of a load of 15 items), the use of tap water is characterized by performances
comparable with those of a refilling system based on PET bottles used for 25 times and
characterized by very short distances (40 km). Its performances are however always better
than those of one way systems when characterized by short distances bottling plant-retailers
(40 km) and efficient consumers purchasing trip (total purchasing of 60 items). The impacts
associated with the use of tap water can be minimized by only manually rinsing the container
after its use or, if a dishwasher is used, by carrying out its washing after 4 or 5 uses and by
running the dishwasher only when fully loaded. If a reusable container is used to conserve
46
Executive summary
water, is also important to assure it a long life span (which in the analysis was conservatively
assumed of one year).
If public network water is delivered from public fountains after its quality improvement
(performed after traditional purifying treatments), the use of a private car for its transportation
to consumers house gives a very significant contribution to the impacts of the respective
scenario. In particular, for a distance of 5.5 km the system is characterized by performances
almost comparable with those pertaining to the use of one way bottled water. To achieve
performances comparable with those of an environmentally effective refilling system (with
the features described above), such distance has to decrease beneath 2 km. Therefore if a
system based on the use of public fountains is implemented in a certain municipality, care
should be taken in assuring that the average distance to be covered by a citizen does not
exceed 2-2.5 km, so that the use of a car can be limited or, better, completely avoided. This
can be achieved for instance by ensuring a capillary distribution of fountains on the territory
of the municipality to be served and by limiting their utilisation to the respective citizens. If
glass bottles are used to conserve water, to assure them a long life span (which in the analysis
was conservatively assumed of one year) is also important, while if PET bottles are employed
they should be used for at least 4-5 cycles.
Refilling scenarios result to be characterized by performances mainly dependent on the
transport distance between bottling plants and local distributors, rather than on the number of
times bottles are used. For the same distance, the utilisation of refillable PET bottles appears
to be the most preferable option for packaged water delivering, while the use of refillable
glass bottles is characterized by performances comparable with those involved by the use of
one-way bottled water. If a short distance is instead considered (40 km), the use of a PET
bottles based refilling system still represents an environmentally valid alternative for
packaged water delivering and the use of refillable glass bottles becomes preferable to one
way bottled water. The advantages which characterize the PET refillable system with respect
to one way systems vanish if these lasts are based on a medium (300 km) or short distance (40
km) and the former on a long distance (800 km).
If a refilling system is implemented in a given area, the use of PET bottles appears therefore
to be preferable to the use of glass bottles. Moreover it emerges the importance of establishing
such a system on the basis of short distances between bottling plants and distributors (in the
order of 50 km and at most of 100 km) and, to a lower extent, of assuring that PET bottles are
utilised at least 15 times and glass bottles at least 20-25 times.
Executive summary
47
With regard to the comparison among one-way bottled water systems, the utilisation of 50%
recycled PET bottles is characterized by slightly but not dramatically better performances
than the use of virgin PET or PLA bottles. Therefore, despite the use of recycled material for
bottles manufacturing represents an initial appreciable effort to improve the environmental
profile of one way PET bottled water, it seems to lead to only marginal environmental
savings, lower than those achievable, for instance, by utilising a PET bottles based refilling
system. More meaningful improvements can instead be obtained by reducing transport
distances bottling plants-retailers to about 50 km and if an efficient purchasing trip to retailers
is performed by citizens when a car is utilised (i.e. by purchasing at least 30 items).
The use of PLA for bottles manufacturing appears to have the worst performances, especially
with regard to the eutrophication indicator because of the wide use of fertilizers for maize
cultivation. These results must however be read in view of the lower benefits associated with
the considered end of life options compared to the recycling of PET, which mask the savings
of energy and of fossil resources associated with PLA production with respect to PET.
Composting or incineration of PLA bottles do not appear therefore to be the most sustainable
end of life options and a possible shifting to a large scale production of water packaged in
PLA bottles seems not to be justified in these conditions. Chemical recycling of PLA bottles,
which recent pilot experiences have demonstrated to be a feasible option, might potentially
lead to completely different conclusion but no data are found in its respect. It seems however
improbable that it could affect the primacy of the use of tap water or of a short distance based
refilling system.
On the basis of the outcomes of the study, a decrease of the massive per capita consumption
of one way bottled water currently registered in Italy can be suggested. In those cases in
which the utilisation of a water with a given content of minerals is not requested, the use of
tap water should be instead preferred. Also the establishing of short distance based refilling
systems represents a valid alternative to one way bottled water as well, especially if PET
bottles are utilised.
A development of this work could be therefore to obtain reliable information and data
concerning the process of polylactic acid recycling through its depolymerization to lactic acid
monomers, even if it is recognized that the level of development of such a process is only at
an early stage and unlikely life cycle data are expected to be available within a short period.
Only the impact indicators considered to be the most meaningful are analysed in the present
study, also to limit he comparison among the investigated scenarios within reasonable limits.
48
Executive summary
As an improvement, a more complete framework of the impacts associated with the different
scenarios can be obtained by considering a wider number of impact indicators and, in case,
facilitating the comparison through the utilisation of a unique aggregated index, such as the
one calculable through the Ecoindicator impact assessment method. Obviously this could lead
to a loss of transparency.
INTRODUCTION
Waste prevention has long been pointed out by the European legislation as the primary
objective to be pursued by any waste management oriented policy and strategy. Its role is
particularly reinforced within the last Waste Framework Directive (2008/98/EC) which, for
the first time, urges Member States to establish waste prevention programmes aimed at
identifying reduction objectives and measures, with the view of minimise the impacts of
resources throughout their whole life cycle and not only when they become waste. If the
environmental benefits of decreasing waste generation are evident when this is achieved by
reducing the consumption of a certain good, they are not assured when prevention is obtained
by substituting the consumption of the service provided by a certain product or system with
that of a less waste generating one.
We have therefore recognized how a life cycle perspective should be generally employed to
evaluate the actual environmental performances of a prevention activity, in order to go
beyond the simple reduction of waste which, alone, does not automatically imply to achieve
sustainability.
The goal of this work has been hence twofold. A research on which methodological aspects of
traditional waste management oriented life cycle assessment (LCA) should be adjusted to
account for waste prevention activities is firstly carried out. Two models are thus proposed
and their practical applicability is compared through the analysis of a simplified case study.
One of the proposed model is then applied to the analysis of those activities which could be
undertaken to reduce the amount of waste generated from the consumption of drinking water
by consumers: the utilisation of public network water and of a returning and refilling system.
These activities are chosen since they are considered to be among the most meaningful for the
Italian context. Last available data show indeed how Italy sits at the first place among
European countries, and at the third in the world, with regard to bottled water consumption,
the major part of which (around 79%) takes place through the wasteful practice of utilising
one way polyethylene terephtalate (PET) bottles.
More precisely, three baseline scenarios characterized, respectively, by the utilisation of
virgin PET, of 50% recycled PET and of polylactic acid (PLA) one way bottled water are
50
Introduction
firstly assessed. The former is indeed representative of the current situation, while the second
and the third represent two possible perspective scenarios for the Italian context. These
scenarios are compared with two public network water preventive scenarios in which purified
groundwater from the tap (real case of Milan) and purified surface water from public
fountains (real case of Florence) are respectively utilised. Finally, two returning and refilling
scenarios which foresee the utilisation of glass and of PET refillable bottles are considered.
Focusing on the performances of the different delivering options, only the management
processes of the waste generated by the alternative systems are considered within the life
cycle modelling while other possible waste fractions are excluded.
The work is organized as follows. After having set the position of waste prevention in the
European legislation and specified its definition, a review of the most meaningful prevention
activities targeting municipal solid waste is presented in chapter 1, along with some possible
criteria for their classification. Some indications concerning the consumption patterns of
drinking water in Italy, along with a brief outline of the legislation regulating water intended
for human consumption are finally provided.
In chapter 2, after a brief introduction to the LCA methodology and its applicability to the
analysis of integrated solid waste management systems, two conceptual waste management
oriented LCA models able to include prevention activities are proposed by amending already
available models and on the basis of other suggestions provided in the literature.
The practical applicability of the proposed models is compared with that of one literature
model through the analysis of a simplified case study in chapter 3, trying to outline the major
differences and similarities emerging during this process.
In chapter 4, once defined the goal and the functional unit, the life cycle inventories of all the
scenarios to be analysed have been carried out by considering the most important material and
energy flows associated with the processes involved in each investigated system. Primary data
are preferably utilised during the modelling and when not possible, literature data as well as
estimation through mass balances or reasonable assumptions are employed. The considered
impact assessment categories with the respective characterization methods are also specified.
After having presented and discussed the results obtained on the basis of the hypotheses
utilised in the inventory, in chapter 5 a sensitivity analysis is also performed on those
parameters which were arbitrarily assumed during the inventory and resulted or expected to
have a significant influence on the outcomes, as well as on those parameter subject to great
Introduction
51
variability. Remarks and recommendations are also provided on the basis of the results of the
analysis.
Major limitations of the study as well as suggestions for possible future improvements are
finally provided.
52
Introduction
CHAPTER 1
BACKGROUND ON WASTE PREVENTION
1.1 Legislative framework at European level: waste hierarchy and
definitions
The concept of waste prevention appears in the European Legislation with the first Waste
Framework Directive 75/442/EEC (European Council, 1975) which requested Member States
to take appropriate measures also aimed at encouraging the reduction in the quantities of
certain waste. Some years later the European Commission in its communication concerning
the first Community Strategy for Waste Management (Commission of the European
Communities, 1989), developed in the context of the Fourth Community Environment Action
Program and based on the principle of preventive action, established a hierarchy of principles
in which waste prevention holds the higher priority and which still now constitutes the basis
of legislation and policy in matter of waste management at European level. It was indeed
confirmed in the review of the Community Strategy for Waste Management (Commission of
the European Communities, 1996) and particularly reinforced within the new Waste
Framework Directive 2008/98/EC (European Parliament and Council, 2008) where it is
explicitly termed as waste hierarchy. In the hierarchy to the primary role of waste prevention
follow then preparing for re-use, recycling, other forms of recovery (such as energy recovery)
and, only in last instance, safe disposal (figure 1.1). Therefore the best option to deal with
waste would be not to generate it at all. Waste which cannot be avoided should be instead
preferably recycled or, in second instance, recovered in other forms, while disposal should be
limited to waste for which no possibility of recovery exists.
54
Chapter 1. Background on waste prevention
Prevention (including re-use)
Most
favoured
option
Preparing for re-use
Recycling
Other forms of
recovery
Disposal
Least
favoured
option
Figure 1.1: Graphical representation of the concept of waste hierarchy so as described by the recent Waste
Framework Directive 2008/98/EC
The background in which the new Waste Framework Directive is placed is the one in part
traced by the Thematic Strategy on the prevention and recycling of waste (Commission of the
European Communities, 2005) whose development represents a priority action of the Sixth
Community Environment Action Programme (European Parliament and Council, 2002) to
pursue the overall aim of decoupling resources consumption and waste generation from the
rate of economic growth as well as the more specific objectives of achieving a significant
overall reduction of the volume and the hazardousness of generated waste through waste
prevention initiatives, better resource efficiency and a shift towards more sustainable
production and consumption patterns. Another priority action is also the development and
implementation of measures on waste prevention by establishing a series of reduction targets
to be achieved at Community level within 2010, sensitizing citizens to their potential
contribution on waste reduction and defining operational measures to encourage waste
prevention.
On these bases the Thematic Strategy on the prevention and recycling of waste (Commission
of the European Communities, 2005; 2003) firstly recognizes that although waste prevention
has been the first priority of Community and national policies for many years, overall waste
quantities continue to increase in most European countries and, in the absence of additional
policy measures, they will continue to do it for the foreseeable future. This is partly explained
by the fact that during past attempts to establish waste prevention targets they were sometimes
defined without providing a reason and the means for their achievement as well as in the
absence of a valid assessment of waste generation patterns in the respective sectors and of a
comprehensive strategy to promote waste prevention. Moreover, being waste generation
55
trends driven by production and consumption patterns, it recognizes how it is difficult to deal
with waste prevention leaving aside policies oriented at resources management and at
products. Therefore considering that beyond to imply the impacts associated with their end of
life treatments, an increasing waste generation trend could be also a symptom of
environmentally inefficient use of resources, the Strategy proposes, among the others, also
some measures aimed at promoting waste prevention. The most important of them is the
inclusion in the Waste Framework Directive of the obligation for Member State to develop
public waste prevention programmes, in the context of sustainable production and
consumption.
Other measures are represented by the diffusion of the IPPC (Integrated Pollution Prevention
and Control) Directive, of the Integrated Product Policy (IPP) and of other tools to encourage
the diffusion of best practices in matter of waste prevention. In particular the IPPC Directive
can help in reducing waste generation at industrial level, during the manufacturing of
materials and product. Integrated Product Policy aims instead at reducing the impacts of a
product or service during its whole life cycle and therefore implicitly also waste generation.
On the contrary of what established in the Sixth Community Environment Action Programme,
the strategy does not consider to be appropriate the prescription of waste prevention targets at
Community level, intended as reduction objectives. This because so defined targets do not
account for the environmental impacts associated with their achieving: increased overall
impacts could instead correspond to a meaningful reduction of the quantity of generated waste
while, on the contrary, small reductions of waste amount could lead to significant reductions
of impacts. A life cycle perspective which takes into account the whole life cycle of resources
is instead fostered. The aim of a waste policy should be indeed to minimise the environmental
impacts throughout the entire life cycle of resources, rather than only to achieve waste
reduction or increase recycling.
The new Waste Framework Directive embodies therefore all these principles and beyond
reformulating and reasserting the above mentioned concept of waste hierarchy provides the
first legal definition of waste prevention at European level. In particular it is defined as:
56
measures taken before a substance, material or product has become waste, that reduce: (a)
the quantity of waste including through the re-use of products or the extension of the life span
of products; (b) the adverse impacts of the generated waste on the environment and human
health; or (c) the content of harmful substances in materials and products (European Council,
2008).
Therefore a key aspect is that prevention strictly takes place before a material or product
becomes waste and is strongly different from other waste management options, such as
recycling or energy recovery, that can be applied only when materials or products are
recognized as waste and which aim at reducing the amount of waste to be disposed of. These
options, along with prevention, can be indeed considered to be part of the broader concept of
waste minimization or waste diversion (OECD, 2004)1.
Preventive activities can take place on materials/products that have already been
manufactured or not. The former is the case of product re-use which, as a matter of fact, is
considered to be part of waste prevention and in particular is defined as any operation by
which products or components that are not waste are used again for the same purpose for
which they were conceived. Reuse can indeed be seen as a form of prevention at two different
levels: it postpones the moment in which a material or product enters the waste phase,
contemporarily diminishing the need of manufacturing new products, but it also prevents the
amount of products entering the waste phase (European Commission DG Environment,
2010).
Moreover the definition of waste prevention differentiates between a quantitative and a
qualitative aspect. While the former refers to the reduction of the amount of waste generated,
the latter refers instead to the reduction of the adverse impacts on the environment or human
health potentially associated with traditional waste treatments (i.e. because of airborne
emissions) or with harmful residues in products made from recycled material. Since these
adverse impacts can also be caused by harmful substances contained in waste, their reduction
is also considered to be part of the concept of qualitative preventive measures. Qualitative
prevention therefore does not exclude the application of the other management options of the
waste hierarchy.
1
In particular, waste minimization is defined in OECD (2000) as “preventing and/or reducing the generation of
waste at the source, improving the quality of waste generated, such as reducing the hazard, and encouraging reuse, recycling and recovery”.
57
Quantitative and qualitative aspects are however not exclusive but supportive each of the
other and therefore even if the treatment of a certain waste does not involve any meaningful
impact, it does not imply that its generation should not be prevented. Indeed even if it is
recycled, energy and other natural resources utilised to make its raw materials available and to
bring them into a useful form are lost, moreover the recycling process would require
additional energy and natural resources. From the other hand, even if the generation of a
given amount of a certain waste has been prevented, this does not mean that qualitative
prevention on the remaining or not-avoidable waste is no longer needed (European
Commission DG Environment, 2010). However we anticipate that in this work the focus will
be on the quantitative aspect of waste prevention.
It is finally possible to notice that (figure 1.1), on the contrary of re-use, the Directive
considers preparing for re-use not to be part of waste prevention because it deals with
materials or products that have already entered the waste phase. It is indeed define as
checking, cleaning or repairing (recovery)2 operations, by which products or components of
products that have become waste are prepared so that they can be re-used without any other
pre-processing. However it can be argued that the difference between reuse and preparing for
reuse is merely a legal issue which depends by the fact that a product or material is legally
recognized as waste or not (European Commission DG Environment, 2010). For example
washing of bottles belonging to a returning and refilling system would be considered a reuse
activity, while delivering a broken bicycle (which the owner intends to discard) to a charity
shop for its repairing would be preparing for reuse (ACR+, 2010; European Commission DG
Environment, 2010) but it is clear how in both cases the result is the same and the only
difference is the fact that the refurbishing or repairing operation is performed on a product
recognized as waste or not. Figures 1.2 aims at clarifying the definitions given up to now.
2
The official definition reports this term but it probably represents an error.
58
Products/Materials
Waste
Prevention
(including products re-use)
Preparing for re-use
Recycling
Other forms of recovery*
Disposal
Waste prevention
Waste minimization
Waste disposal
(*) Other forms of recovery option is represented as a borderline case since the Waste Framework Directive
states that utilising waste for energy generation can be considered a form of recovery only if a given energy
efficiency is achieved in the process.
Figure 1.2: Representation of the position of the various step of the waste hierarchy (Adapted from ACR+
(2010))
As requested by the Thematic Strategy on the prevention and recycling of waste the new
Waste Framework Directive includes the innovative aspect of national waste prevention
programmes that Member States are urged to establish within December 2013. In these
programmes waste prevention objectives have to be established and applicable waste
prevention measures identified. Moreover Member States are also requested to determine
appropriate qualitative or quantitative benchmarks with the aim of monitor and asses the
progress obtained through undertaking waste prevention measures. For the same purpose they
can also determine qualitative or quantitative targets and indicators.
On its part the Commission engages itself to create a system for sharing information on best
practices in matter of waste prevention and to develop guidelines in order to assist Member
States in the preparation of the Programmes.
It is also worth to notice that according to the principle outlined by the Thematic Strategy on
prevention and recycling of waste (Commission of the European Communities, 2005), the
Directive declares that the aim of waste prevention objectives and measures is to break the
link between economic growth and environmental impacts associated with waste generation
and not simply with waste generation. Therefore not the only mere waste reduction has to be
pursued but rather the minimisation of the impact of a material or product (in a broader sense,
of a resource) throughout its whole life cycle and not only in the waste phase. One of the most
59
important quantitative based tool supporting this perspective is just the life cycle assessment
(LCA).
We can therefore recognize that, as also Wilson et al. (2010) point out, rather than being only
an option to deal with waste, their prevention is placed in a broader context of sustainable use
of natural resources and sustainable consumption and production (SCP) patterns which in turn
are part of the overall goal of sustainable development. According to the same authors these
concepts and that of waste management are beginning to merge together into an holistic
approach which has the overall aim of reducing the environmental impacts associated with
societal consumption and production pathways, while maintaining or also improving levels of
economic welfare and standard of living. In this context waste managers increasingly see
themselves as ‘sustainable resource managers’.
With regard to waste prevention the Directive finally establishes that the Commission has to
prepare, also on the basis of stakeholders consultation, a series of reports accompanied, if
appropriate, by proposal of measures in support of prevention activities and of the
implementation of waste prevention programmes. These reports shall consist in:

an interim report on the evolution of waste generation and the scope of waste
prevention, including the formulation of a product eco-design policy aimed also at
reducing both the generation of waste and the presence of hazardous substances in
them, as well as at promoting technologies focusing on durable, re-usable and
recyclable products;

the formulation of an action plan for further support of measures aimed at changing
current consumptions patterns.
In addition the Commission shall set by the end of 2014 waste prevention and decoupling
objectives for 2020, based on best available practices.
60
1.2 Possible classification of waste prevention activities
Because of the extreme variability of typologies of waste prevention activities, several options
have been utilised in the literature for their classification.
A quite exhaustive list of possible criteria is provided by Salhofer et al. (2008) and is briefly
reported in table 1.1 with some adaptations.
Table 1.1: Possible criteria for the classification of waste prevention activities according to Salhofer et al.
(2008)
Criteria
Waste stream
(type of waste intended to be reduced)
Target group
(actors who are asked to prevent waste)
Instruments
(way through which an actor chooses to
influence the behaviour of another actor)
the term measure indicates instead the
concrete realization of an instrument














Purpose
(result that wants to be achieved through
a measure)


Classification
By material (paper, hazardous waste,...)
By product (packaging, diapers,...)
By source of generation (household, industry,...)
By field of application (big events,...)
Citizens/consumers
Retailers
Producers
Public administrators (i.e. waste managers)
Regulatory instruments (laws, licenses, product standards,...)
Economic instruments (subsidies, incentives, charges,...)
Collaborative agreements (public-private agreements,
certifications and labels,...)
Services and infrastructures (repairing, second hand shops,...)
Communication and diffusion (presenting information, persuading
about available options,...)
Reduction at source (complete avoidance, reduction by
optimisation of a process,..)
Substitution (one-way by refillable packaging, by a less hazardous
material,...)
Reuse (extension of product use phase, increased use of a product
by sharing,...)
Cleary (2010b) proposes instead a more general classification in the attempt to set municipal
solid waste prevention activities in a life cycle perspective. In particular two typologies of
activities are distinguished:
1. Waste prevention activities through dematerialization: activities that involve the
reduction of waste generation by totally or partially substituting the service provided
to consumers by a certain product system with that provided by a less waste
generating one, without affecting the magnitude of the service to be provided (both
product systems are functionally equivalent). Product re-use is considered to be a form
of dematerialization as well.
61
2. Waste prevention activities through reduced consumption: activities that involve the
reduction of waste generation by reducing the consumption of the service provided by
a certain waste generating product system.
Of course not all the possible prevention activities belong, in principle, to these two
typologies but in some cases can be assimilated to them.
The author finally highlights the fact that certain activities, such as home composting or
grass-cycling, are sometimes incorrectly pointed out as preventive while they are actually not
such. Indeed in these cases waste is however generated but is not collected and managed
through conventional treatments. The suggestion to consider them as form of waste diversion
activities is therefore given by the author.
A not exhaustive list of possible prevention activities classified according to the above
mentioned criteria is given by Cleary and is reported in table 1.2 with some adaptations.
62
Table 1.2: Examples of waste prevention activities classified according to the criteria proposed by Cleary
(2010b)
Type of waste
prevention activity
(WPA)
Reduced consumption
Reduction of material
consumption without
substituting the service
provided by the product
system
Presence of
alternate
product
system(s) that
generate
additional waste
for treatment
Example(s)
Reduction of the amount
of consumed product
services
No
 Reduce generation of “junk mail”
 Double side printing and copying
 Reduce food wastage by
improving one’s own purchasing
behaviour
Substitution of
functionally equivalent
product services
No
Reuse of a disposable shopping bag
Effect of WPA type on
product service(s)
Dematerialization
Reuse of a disposable
good*
Substitution of a service
provided by disposable
good with that of a
capital good
Substitution of a
disposable good
with a reusable one
Lightweighting of a good
Lengthening the useful
lifespan of a durable good
Substitution of
functionally
equivalent product
services
Yes
(substituted
capital good)
Substitution of
functionally
equivalent product
services
Yes (substituted
reusable good)
Substitution of
functionally
equivalent product
services
Substitution of
functionally
equivalent product
services
 Drink tap water instead of bottled
water
 Read on-line newspaper articles
instead of printed on newsprint
 Dry hands by means of hand
dryers instead of hand towels
 Substitution of one way bottles for
beverages with refillable ones
 Substitution of one way containers
with reusable ones for detergents
distribution
 Substitution of disposable
shopping bags with reusable ones
 Substitution of disposable nappies
with reusable ones
Yes (substituted
disposable
good)
Substitution single use of glass
containers with lightweight plastic
single use ones
Yes (substituted
durable good)
Increase the useful lifespan of a
refrigerator through improved
design
Waste diversion (prevention at collection)
Domestic/on-property
 Home composting
No effect
No
waste treatments
 Grass cycling
Temporarily storage of
waste products and
No effect
No
Storage of obsolete appliances
materials
(*) In our view this activity would be more properly considered to take place through reduced consumption
A thorough attempt of identification of possible criteria for the classification of prevention
activities is proposed in a recent study carried out on behalf of the European Commission
63
(European Commission DG Environment, 2010) which constitutes a background work for the
redaction of the reports that the Waste Framework Directive requires to be prepared by the
Commission itself (paragraph 1.1). The framework which emerges is quite complex and
articulated probably in view of the fact that, as we have tried to highlight in paragraph 1.1,
waste prevention is a measure belonging to policies at the borderline between sustainable
waste management and sustainable consumption and production.
Since the mentioned source contains the bases on which the European Commission will build
up its opinions, we have considered meaningful to briefly describe the four criteria which,
separately or combined together, are proposed in order to classify waste prevention activities
(WPA). In particular, they are:
1. The effects that WPAs generate: quantitative or qualitative prevention;
2. The stage in the material life cycle where WPAs take place. In particular the following
stage are specified together with some examples of possible general preventive
measures/strategies and of more specific activities that can be undertaken in the stages
themselves. Alternatively the overall goal to be pursued to achieve waste prevention is
indicated.

design: even if it is not a physical life cycle stage, it is considered because during this
phase decisions are taken on the typologies and amounts of materials that will be used,
influencing therefore the quantity and the hazardousness of the product that eventually
will become waste. With regard to waste prevention this stage can contribute to
develop products requiring less materials and hazardous substances input (including
distribution packaging), less need of substitution of consumables, of replacement of
spare parts, of maintenance and with a longer life span.
At a more strategic level prevention can also take place if a service is chosen instead
of a physical product to serve the same purpose (dematerialisation) or when a strategic
choice is made not to develop a certain product or a certain market. The overall goal of
this stage is therefore the reduction of the environmental impact of a given product or
service throughout its future entire life cycle and not only the reduction of the amount
of materials and resources to be utilised and that eventually become waste. Such an
approach is referred to as eco-design.
64

extraction of raw materials: the goal to be pursued in this stage is the improving of the
efficiency of extraction processes to involve the increase of the ratio between usable
extracted material and waste from extraction. Waste originating from these activities
(but also from harvesting of agricultural products) are often termed as hidden flows
since they often remain in the country of origin and are not more visible to the user of
materials after their importation.

production (through possible multiple sequential phases): the goal to be pursued is the
prevention of pre-consumer waste through technical measures aimed at improving
resources efficiency of manufacturing processes.

distribution and retailing: the goal to be pursued is the prevention of waste during
transport, storage and distribution of products. Preventive measures are therefore
focused on reducing primary secondary and tertiary packaging as well as on reducing
losses or damages during transport and manipulation of goods, or losses through
overstock of perishable goods (mainly food) that would have to be disposed of
because they could not be sold any more. Provided examples are:
-
utilisation of reusable transport packaging, including re-usable pallets,
-
imposition of ban or tax on single use bags,
-
adopting the provision consisting in the obligation of retailers to provide along
with products packaged in single use packaging also comparable products that
make use of reusable packaging (i.e. self dispensing systems), so that the
consumer is free to chose between the two alternatives.
Preventive measures in the distribution stages are often largely influenced by those
concerning the design stage, where decisions have to be taken with regard to
packaging minimisation through an eco-design perspective.

use/consumption: the goal is the prevention of household waste and of
commercial/industrial waste not originated by production/extraction activities.
Preventive measures should be therefore aimed at influencing consumers behaviour
towards less waste generating choice of purchasing and of consumptions, at reducing
consumptions of consumables when using an equipment (i.e. print toner, car lubricant,
65
batteries and so on) as well as waste generation during repairing or maintenance
operations. Provided examples are:
-
reduction of food wastage through a discerning planning of purchases and/or
utilisation of leftovers,
-
smart shopping: buy bulk products, products packaged in refillable containers
and avoid over packaged products,
-
product reuse: utilise reusable bags and nappies, buy reusable packaging and
second hand products,
-
prohibit the delivering of junk mail,
-
buy services instead of goods (i.e. buy experiences such as concerts and
theatrical performances as gifts instead of material products),
-
utilise a product as long as possible and, if practicable, consider repairing
and/or upgrading instead of its discharging.
Prevention measures in the use/consumption stage are often closely associated with
measures in the distribution/retailing stage. For instance consumers can perform the
choice of less waste generating products only if retailers give them this possibility.
Similarly the choice of returnable and refillable bottles is conditioned by the
availability of such a distribution system.

waste phase: prevention measures in this phase are difficult to distinguish from other
waste management options. They would be aimed especially at reducing the amount
of scraps originating during recycling processes. However such an improving is not
considered as a quantitative waste prevention but merely as a quantitatively better
performing recycling activity.

end of waste phase (start of a new life cycle as recycled product): prevention in this
phase is mainly concerned in its qualitative aspect and especially it would be aimed at
avoiding that recycled products contain hazardous substances potentially included in
the waste that have been recycled, or originating during the recycling process itself.
66
3. The nature of the policy instrument through which WPAs are promoted. In particular the
following typologies of instruments are distinguished:

Regulatory or legal instruments: tools such as standards or directives that regulate the
behaviour of interested subjects through penalties for who do not comply with the
regulatory provisions.

Market-based or economic instruments: tools that influence the behaviour of the
interested subjects through economic signals such as taxes and subsidies.

Suasive or communication instruments: tools that encourage change in behaviour of
the interested subjects through the providing of information and education, such as
public awareness campaigns, publicity of sustainable products, education of public
purchasers and so on.

Technical instruments: this category is established to cover eco-design and reuse
measures that appear to be of a more technical nature and can be supported by the
three typologies of instruments described up to now.
4. The phase of the DPSIR cycle which WPA influence.
The DPSIR is a model which describes the dynamic of the interactions between society and
the environment and is based on the concepts of driving forces (D), pressure (P), state (S),
impact (I) and responses (R). Prevention measures are always response and can be classified
on the basis of the other phases of the DPSIR cycle which they are aimed at influencing (D, P,
S or I).
The report also underlines how often it is not possible to attribute a prevention activity (or a
general measure) to a single dimension of a certain criterion (except for the first one) since an
activity might or must belong to more than one of them. For instance the providing to
consumers of a product which allows to achieve dematerialization (i.e. reusable nappies)
needs also that consumers themselves are sensitized or arbitrarily decide to make use of that
product. According to the life cycle based classification criteria it is clear therefore how a
prevention activity, which from one hand takes place at the design stage, needs also to be
accomplished at the use/consumption stage through a consumer choice to achieve its effect.
Adopting the classification on the basis of the nature of the policy instrument through which
prevention is promoted it is instead evident how beyond a technical instrument (eco-design in
67
this case) also economic instruments (such as taxes on disposable products or pay-as-youthrow schemes), market-based instruments (such as promotional campaigns or discount
coupons) and communication instruments (such as public awareness raising/education
campaigns and publicity) would be needed.
Another examples is represented by the case in which consumers decide to purchase, for
instance, bulk food products. It is clear how to sort its effect this decision has to be
accomplished by the fact that the possibility to buy bulk food product is actually given to
consumers by the same retailers.
As far as prevention of municipal solid waste is concerned, prevention strategies or activities
of major interest are those taking place within distribution/retailing and use/consumptions
stages as well as, for the reasons explained above, also during the design stage of a product
life cycle.
In particular with regard to the distribution/retailing stages the most important instruments
contributing to waste prevention are recognized to be product standards and market bans
(legal instruments), awareness raising and education campaigns (communication instruments),
as well as eco-design as technical instrument aimed at minimising primary, secondary and
tertiary packaging.
With regard instead to the use/consumption stage, economic instruments such as tax on single
use products, pay as you throw schemes, promotional campaigns or discount coupons for
reusable products as well as the implementation of deposit and refund schemes for single use
packaging (i.e. bottles) are recognized to be valid alternatives. An as much important role is
also considered to be hold by communication instruments such as awareness raising/education
campaigns and publicity of sustainable products outside and inside stores.
1.3 Review of major prevention activities targeting municipal solid waste
In order to perform a brief but quite exhaustive review of waste prevention activities targeting
municipal solid waste those sources considered to be more reliable and authoritative among
the several available, are taken into account.
First of all we have recognized how a noteworthy work presenting the most important
prevention activities that citizens and organizations can, voluntarily or encouraged by public
authorities undertake, has been recently carried out by the Association of Cities and Regions
68
for Recycling and Sustainable Resource Management (ACR+, 2010). Activities and, when
possible, the amount of waste eventually reduced through their implementation, are
individualized on the basis of real experiences of best practices engaged during recent years
by several local and regional authorities or organizations.
Results obtained through the single best practices aimed at the same purpose are then utilised
to estimate the amount of waste that could potentially be reduced through the implementation
of a given prevention activity (termed as prevention potential). A summary of the
individualized activities, classified according to the targeted waste stream (organic waste,
packaging waste, paper waste, bulky waste and nappies and other municipal waste) and the
respective estimated prevention potentials expressed as kg/inhabitant/year, are reported in
table 1.3. An estimate of the average amount generated at European level for each considered
waste stream is also provided. Only macro-groups of activities are specified in the table, while
each specific activity mentioned in the work will be instead considered to carry out the overall
review of prevention activities that will be presented in table 1.5.
As it can be noticed an overall amount of municipal solid waste of 600 kg/inhabitant/year is
estimated to be generated on average at European level, while an overall reduction of 100
kg/inhabitant/year (about 17%) is expected to be achieved through the implementation of all
the considered prevention activities. “100 kg less per inhabitant” represents therefore the
European benchmark estimated by ACR+, which local and regional authorities should aim at
achieving by identifying and applying those best practices which, among the ones proposed,
they consider to be more appropriate for the respective context.
However the same ACR+ highlights that the provided prevention potentials strictly refer to
the initial waste quantity with respect to which they are defined (those reported in table 1.3).
Therefore for their transposition to a specific reality it is not their absolute value to be worth
but rather the percentage reduction to which they are associated with. Moreover, despite the
practical and concrete nature of such quantitative parameters, all the considerations made in
paragraph 1.1 concerning the fact that an overall reduction of the environmental impacts, and
not the mere waste reduction has to be pursued through prevention activities, must well be
kept in mind.
Despite these objective limitations, the mentioned work actually represents a valid instrument
aimed at supporting Member States to establish waste prevention programmes as well as in
that process of qualitative and quantitative benchmarking which the same Waste Framework
Directive requires them. Benchmarking (individuation of parameters) can indeed be meant as
69
the identification of best practices (qualitative benchmark) and the associated prevention
potentials (quantitative benchmark) to be used as bases for the setting of target and indicators
to be achieved through identified best practices. Benchmarks are not static but are intended to
be continuously improved during time along with waste reduction achievable through best
practices.
Table 1.3: Prevention potentials estimated by ACR+ (2010) for individualized waste prevention activities
Prevention activity by waste stream
Packaging
Encourage/prefer the use of reusable or
returnable/refillable packaging
Promote/prefer drinking of tap water
Encourage/prefer the use of reusable shopping bags
Fight excessive packaging
Paper
Reduce unwanted and unaddressed mail (junk mail)
Encourage offices dematerialisation through ICT
Reduce the use of kitchen, tissue and bathroom towel
paper
Organic waste
Act against food wastage
Green scaping (Green landscaping)
Smart gardening
Home, community and on-site composting
Nappies and other wastes
Swap to reusable nappies and incontinence pads
Other municipal waste prevention strategies
(bicycles, paintings leftover, hand tools, garden tools,
toys)
Bulky waste
Promote clothes and other textiles waste prevention
Promote furniture waste prevention
Promote WEEE* prevention
Total
(*) WEEE: Waste from Electric and Electronic Equipment
Average
generation
in Europe
(kg/inhabitant/year)
150
Prevention
potential
25
35
12
6
2
107
2
1
10
100
15
75
10
15
4
9
2
220
40
30
10
90
10
100
20
78
18
60
8
2
6
52
15
20
17
12
4
4
4
600
100
A second important source is represented by the already mentioned work of Salhofer et al.
(2008) which have estimated the prevention potentials for some prevention activities targeting
five different waste streams (advertising material, beverage packaging, diapers, food waste
and waste from big events) for the city of Vienna (Austria). Activities and potentials are
summarized in table 1.4. Also in this case the authors point out how, due to the varying nature
of consumption patterns from region to region and by time, prevention potentials are, in
principle, valid only for defined basic conditions in a given area and year.
70
Table 1.4: Prevention potentials calculated by Salhofer et al. (2008) for some municipal solid waste prevention
activities applicable to the city of Vienna
Waste
stream
Advertising
material
Beverage
packaging
Diapers
Food waste
Waste from
big events
Prevention activity
a) Prohibition on unwanted
advertisement
b) Information about the
possibility to apply “no junk
mail” stickers on mailboxes
a) Fix refilling quotas at 60%
b) Fix refilling quotas at 82%
Promoting reusable diapers
a) Donation of still edible foods
discarded by discounts,
supermarkets and bakeries to
food banks
b) Reduce household food
wastage by improving
purchasing behaviour
Substitute one way dishes
Amount of the
targeted waste
stream generated
Prevention
potential
a) 5.7
28
36.4
13.3
a) not quantified
b) 3.7
a) 7.0
b) 16.7
2.0
a) 3.3
b) 35.6
b) (11.5% of total
waste generated)
5.5
0.8
The information provided in the factsheets prepared by the European Commission (EC
Environment, 2011) to promote the diffusion of best practices among Member States are also
considered to widen the framework. They consist in a review of the most effective municipal
solid waste prevention activities and strategies, selected among successful experiences
undertaken up to now by Member States of the European Union or abroad states.
Finally the Italian guidelines on prevention of municipal solid waste prepared by
Federambiente are also resulted to be an important source of information (Federambiente,
2010), as well as the Action Plan for Waste Reduction of the Lombardia Region (Regione
Lombardia, 2009) and the proposal project of municipal waste management plan of the
Piemonte Region (Regione Piemonte, 2009).
Municipal solid waste prevention activities that we have recognized to be the most
meaningful among those reported by all the mentioned sources are utilised to compile the
review reported in table 1.5. As in the ACR+ (2010) report, selected activities are presented
by targeted waste flow and, when possible, they are also classified according to Cleary
(2010b) criteria by specifying if they would take place through dematerialization or reduced
consumption. For completeness also waste diversion activities are reported in the table,
highlighting however their actual nature. Public authorities could indeed be interested in
71
fostering the implementation of also such kind of measures in order to reduce the amount of
waste to be collected and managed through conventional treatments.
A last study concerning waste prevention which is worth to be mentioned is the thorough
review of evidence on household waste prevention carried out on behalf of Defra, the British
Department for Environment and Rural affairs, in order to provide to it an evidence-based
platform for the formulation of future policy measures in matter of waste prevention (Defra,
2009; Defra 2011). It is constituted by a series of reports which mainly deal with consumers
behaviour (what they voluntarily do at home to prevent waste and why), how retailers and the
third sector contribute to reduce the amount of materials entering consumers houses and
which policy measures can encourage consumers to rethink their behaviour towards waste
reduction. The presentation of their content would however be beyond the scope of this work.
Finally we have recognized how a noteworthy initiative aimed at raising public awareness
with regard to sustainable waste reduction as well as at promoting changes in production and
consumption patterns through the sharing and the diffusion of best practices is represented by
the European Week for Waste Reduction (EWWR, 2011). It has been taking place annually
since 2009 with the support of the European Commission in those nations or regions which
desire to participate, also outside Europe. The event will be organized up to 2011
72
Table 1.5: Review of the most important municipal solid waste prevention measures and activities on the basis of different sources
(ACR+, 2010; European Commission, 2010; Federambiente, 2010; Regione Lombardia, 2009; Regione Piemonte, 2009; Sahlofer et al., 2008)
Prevention measures and activities by waste flow
Packaging waste
Encourage/prefer the use of reusable or returnable/refillable packaging:
Classification
 prefer the purchasing of spine (loose) cleansings and detergents (i.e. for clothes, dishes, floors, hard surfaces) dispensed in reusable containers
instead of those packaged in one-way containers.
The same concept has been applied in some cases also to milk and wines delivering. In the case of milk the delivering has taken place not only
in the great distribution but also from automatic distributors placed in public spaces1,
Dematerialization
 prefer the purchasing of returnable and refillable bottled beverages instead of those packaged in one-way bottles
(the needs of the returning trip with empty bottles might involve, in some cases, an increase of the overall impacts of such a system, even if
waste reduction is achieved);
 (At distribution level) prefer the use of reusable crates as transport packaging for fruit and vegetables (such as plastic crates with collapsible side
boards) to one-way crates.
Promote/prefer drinking of tap water (directly from the network or further purified) instead of bottled water
 At consumer level: through information campaigns, installation of public fountains in public places (squares, parks, museums), schools,
universities, public offices, places of work; developing a local tap water brand and taxation or ban of the use of one-way bottled water.
Dematerialization
(Alternatively to reusable bags also collapsible reusable cardboard boxes can be utilised in place of single use bags)
Dematerialization
their use can be promoted through information campaigns in case associated with the free initial distribution of reusable bags, taxing or banning
single use bags and offering discounts when clients bring their own shopping bags.
continues on next page
(1) The example refers to an Italian project which had a broader scope of establishing a system of short chain (filiera corta) with the aim of reducing the number of
intermediary subjects between producers and consumers in order to preserve zootechnic factories from extinction. In this case waste prevention is expected to implicitly
involve social and economic benefits beyond environmental benefits. Also the case of wine is associated with the willing of establishing a short chain system with the aim
of reducing transport distances.
(2) HORECA: Hotellerie, Restaurant and Café (or Catering).
 At HORECA2 level: serving tap water as a standard practice in restaurants, cafes, canteens and so on.
Encourage/prefer the use of reusable shopping bags of natural fibres, woven synthetic fibres or thick plastic instead of single use plastic or paper
bags
At consumer level
 Prefer supplying and purchasing of bulk (loose) dry food products through direct dispensers such as pasta, rice, legumes, cereals, dry fruits,
biscuits, sweets, chocolates, coffee, spices, and in some cases also pet food (self-dispensing of products), rather than individually packaged.
Dispensed products are packaged within lightweight (biodegradable) plastic bags.
When possible this concept should be applied to all merchandises in general;
 if purchase bulk products is not possible, prefer those with minimal packaging (i.e. toothpaste tubes without external cardboard box) and/or in
concentrated form (i.e. detergents).
Dematerialization
At producer/distributor level
 Reduce packaging weight;
continues from previous page
Avoid the excessive use of packaging
 work with producers to minimize the packaging used to protect their products as well as empty spaces in packaging, encourage producers to the
use of reusable containers for products transportation as well as to reuse or repair pallets.
Paper waste
Reduce unwanted/unaddressed mail (junk mail) representing advertisement materials delivered to citizens or organizations, through the following
activities:
 Apply a “no junk mail” sticker on mailboxes/doors;
 Adhere to a free registration Mail Preference Services (if available) to have one’s own name and home address removed from (or added to) the
mailing lists utilised by generators advertisement material for its delivering through the service of public mail;
 Directly contact generators of unwanted advertisement material to have one’ own name and address removed from their mailing lists;
 Legally allow the delivering of advertisement material only to households/organizations that formally affirm their wish to receive it;
 Unsubscribe oneself from the service of delivering of any kind of unwanted publication/catalogue in paper format and avoid the subscribing to
new mailing lists when compiling forms.
Even if junk mails
are considered to be
unwanted these
activities can be
assimilated to cases
of
reduced
consumption
Information campaigns should not only aimed at encouraging citizens/organizations to apply stickers but also companies which deliver advertising
material to respect stickers. Fines could be also foreseen if these last was not respected by generators.
73
74
Reduce paper consumptions at home through the following tactics:
1. double side printing and copying;
2. use the blank side of no longer needed single sided printing and copies for notes and memos;
3. print less important documents with smaller characters;
4. substitute fax or paper based communications with digital communications;
5. prefer the use of on line billing and invoicing services.
Encourage offices dematerialisation through Information and Communication Technologies (ICT):
4-5:
dematerialization
1,2,9,10:
reduced
consumption;
Remaining:
dematerialization
All these measures can be promoted by means of information and awareness rising campaigns addressed to employees.
Reduce the use of kitchen paper, tissue paper and bathroom paper towels:
 replace bathroom paper towels with fabric towels or electric hand-dryers nearby offices, schools/universities, administrations and the HORECA
channel;
 prefer kitchen fabric clothes than kitchen paper;
 replace multi-fold paper towels with single or double fold paper roll (in both kitchen and bathroom).
Dematerialization
1. double side printing and copying, reduce margins and font size, prefer the use of lower paper weight, fix a maximum amount of paper per
employee allowed to be used;
2. eliminate cover sheets when sending faxes and set the fax machine to eliminate confirmation sheets;
3. send digital instead of printed faxes and utilise the revision tool of virtual text editors to make corrections/revision of documents;
4. when possible utilise electronic communication instruments for lists, forms, bulletins, manuals, reports, inventories. Utilise e-mails instead of
faxes for announcing meetings and specific communications such as press releases;
5. send preparatory material by e-mails before meetings to avoid printing of physical copies for each participants; encourage the use of personal
computers for note-making or make available blank sides of unneeded single side printed sheets for the same purpose.
6. limit the use of paper invoices, transaction registrations and confirmation letters by allowing the use of online ordering modules and secure webbased money transfers through credit card;
7. chose electronic format of reading materials (reports, newspapers, e-mails) when available;
8. store documents in electronic archives using data compression software to save memory;
9. use the blank side of no longer needed single-sided copies to print draft reports/documents. Prefer passing of reports among all the involved
readers rather than printing different copies;
10. encourage envelopes reuse by applying removable address labels and requiring the use of reusable envelopes for internal communications.
Such envelopes are designed to serve also as return envelope eliminating the need of new envelopes when a reply is required.
1-3:
reduced
consumption;
Organic waste (food and green)
Actions against food wastage:
 at consumer level: improve one’s own purchasing behaviour by avoiding over purchasing, taking into account the real need and the life time of
products, perform a correct storage of purchases, prepare right portions and use or freeze leftovers (These behaviours can be also promoted by
retailers);
 at HORECA3/canteens level: serving adequate portions, charge a supplement if food is left in the plate (for buffets) donate not consumed food to
social canteens, social supermarkets (markets accessible only to people with low income, where products are sold at a very reduced price)3 or
assistance centres for animals (i.e. kennels);
Assimilable to
reduced
consumption
 at commercial premises: sell firstly food close to “use by” or “best before” dates (in case at reduced prices), donate still edible but no longer
sealable food to social canteens, social supermarkets (markets accessible only to people with low income, where products are sold at a very
reduced price)4 or assistance centres for animals (i.e. kennels)
Beyond these “end-of pipe” measures a primary important factor/problem is associated with adequately manage acquisition and selling of edible
food in such a manner to match the offer with the demand by taking into account changes in consumers behaviour. Moreover a proper handling
and storage of incoming edible food have to be performed to limit wastage.
Green scaping (Green landscaping):
 use slow growing grasses where possible (the use of these typologies of grasses requires more care during sawing , moreover a preventive
analysis of the potential effects of their use on local biodiversity have to be carried out to avoid negative or undesirable interactions);
-
 create “meadow-areas”: a field vegetated primarily by grass is left to grow wild (in parts of certain green areas & in household gardens).
Smart gardening:
 grass cycling: leave grass clippings on the lawn after cutting (when utilising this practice mowing have to be carried out with a quite high
frequency in order to avoid the generation of grass bundles which prevent the passage of sunlight and cause an excessive nutrients enrichment of
soil which promotes the growing of wild grass species instead of fine grass, damaging the lawn;
Waste diversion
 use grass, woodchips, leaves and compost as mulching material for trees and bushes: mulch beds should not exceed a depth of 7.5 cm and keep
about 2.5 cm away from stems and trunks;
 remove leaves only when necessary, use branches for wattle or walls.
75
(3) HORECA: Hotellerie, Restaurant and Café (or Catering).
(4) Beyond potential environmental benefits also social benefits are associated with undertaking these prevention activities.
76
Home, community and on-site composting
Waste diversion
Nappies
 Utilise reusable nappies and incontinence pads instead of disposable ones;
 anticipate the time of abandoning of the use of nappy by infants.
Waste deriving from the use of one-way crockery
Reduction of waste deriving from the use of one-way crockery at canteens and refreshment services in general by:
Dematerialization
the first and reduced
consumption the
second
Dematerialization
 substituting one-way plastic crockery with reusable ones (ceramic or plastic dishes, glass or plastic cups, metallic or plastic cutlery).
Waste from big events
Reduce waste from big events such ad exhibitions, sporting events, fairs or folk festivals by:
 substituting one way plastic or paper dishes with reusable dishes made of ceramic or plastic;
 substituting plastic cutlery and cups with reusable ones.
Dematerialization
An alternative qualitative prevention could be achieved by utilising PLA (polylactic acid) biodegradable crockery, especially in those areas where
the utilisation of reusable crockery would be difficult due to a lack of infrastructures or other reasons. PLA should be involved in less impacting
end of life treatments.
Washing of crockery can be carried out on site (at each stand or central station) or at an off site facilities. To encourage customers to returns
crockery, they have to be requested to pay an initial deposit which will be refunded at the moment of returning.
Implementing of such activities could be promoted by regulatory instruments (i.e. general legal prohibition on the use of one way crockery) or
collaborative agreements (i.e. the license for the event is released only after that the organized have assured the willing of utilising only reusable
crockery).
Textiles, furniture, WEEE
Promote clothes and other textiles prevention:




donate clothes and other textiles to charities and reuse centres;
sell/buy clothes and other textiles in second hand markets;
rent, lend and exchange clothes not frequently used instead of buying them (i.e. wedding dresses);
repair or transform clothes and other textiles, changing their use destinations;
Assimilable to
reduced
consumption
Repairing and transforming skills can be promoted for instance by establishing cooperation agreements between primary and secondary schools
and the elderly or by performing training laboratories.
Promote furniture prevention:





exchange of furniture between households, schools and offices;
sell/buy furniture in second hand markets;
donate furniture to others (households, charities or reuse centres and other originations);
organise private sales of furniture supported by local authorities;
repair furniture.
Assimilable to
reduced
consumption
Promote WEEE (Waste from Electrical and Electronic Equipment) prevention:
 exchange of EEE between households school and offices;
 selling EEE through specialized internet sites or newspaper;
 donate EEE to others households, charities or reuse centres and other organizations, where they can be reused directly or repaired/upgraded for
further reuse;
 organise private sales of EEE supported by local authorities;
 repair EEE.
Assimilable to
reduced
consumption
77
78
1.4 Waste prevention and life cycle thinking
The Waste Framework Directive states that when the waste hierarchy is applied, waste
management options have to be chosen in such a manner to achieve the best overall
environmental outcome. Therefore specific waste flows may be requested not to follow the
hierarchy of options if a life cycle perspective, which takes into account the whole life cycle
of resources, justifies it by demonstrating that an overall lower potential environmental
impact is so achieved.
However from the already mentioned European Commission study (European Commission
DG Environment, 2010) it emerges that according to some stakeholders the priority of waste
prevention should not to be subordinated to life cycle assessment studies, which are instead
considered to be complementary to the waste hierarchy and that should be used only where
and when they add values and not in order to delay or dilute prevention activities. In our view
this position is agreeable only in the case in which, according to Cleary’s (2010b)
classification of prevention activities (paragraph 1.2), waste prevention is achieved through
reduced consumption or through activities assimilable to this concept. Indeed, in this case, all
the impacts of all possible upstream and downstream activities associated with the life cycle
of a certain resource are potentially avoided.
On the contrary when prevention takes place through dematerialization activities, a life cycle
perspective should be employed to evaluate if an actual overall decrease of the environmental
impacts associated with their implementation takes place. In particular this is recommended
by the European Commission study (European Commission DG Environment, 2010), when
prevention is going to be achieved by substituting one way with reusable bottles because, as
different literature studies demonstrate, the influence of several factors does not allow to
obtain outcomes of general validity.
Another example is represented by the study of Aumônier and Collins (2005) which have
performed a life cycle assessment comparison between the utilisation of reusable and
disposable nappies in the United Kingdom. In particular from the study it seems to emerge
how the environmental performances of reusable nappies are dependent by their washing
conditions and by the utilisation or less of a mechanical drier. When efficient washing
conditions are utilised (medium temperatures, washing together with other items) and natural
drying is performed, reusable nappies appear to be preferable to disposable ones. On the
contrary when they are washed through inefficient conditions (washed alone at high
79
temperatures) and a mechanical drier is utilised, they performances appear to be worse than
disposable diapers. In this case it is clear how reduction of waste generation would be not
associated with a reduction of the environmental impacts of the whole life cycle of nappies,
how is on the contrary requested by the Waste Framework Directive.
Further details with regard to the importance of employing a life cycle perspective when
evaluating waste (resource) management options will be given in chapter 2.
1.5. Consumption patterns of drinking water in Italy
As anticipated in the introduction, one of the objectives of this work is the analysis of the
activities that could be in case undertaken to reduce the amount of waste generated from the
consumption of drinking water. This particular choice is justified since it is recognized how
the Italian country has been characterized for years by the highest per capita consumptions of
bottled water at European level and, in 2008, it was at the third place in the world (Bevitalia,
2009, Martinelli, 2010). With the only exceptions of the last two years for which data are
available, they have been indeed continuously increasing since 1980, as showed in figure 1.3.
litres/inhabitant/year
200
188
191
193
192
189
2005
2006
2010
2007
2015
2020
2008
2009
2025
167
150
138
100
50
110
65
47
0
1980
1985
1990
1995
2000
Year
Figure 1.3: Evolution of per capita consumptions of bottled water in Italy3 (Elaboration on data from Bevitalia
(2009))
The slight decrease registered for the last two years appears to be ascribable to diverse and
simultaneous factors such as the meteorological conditions, the unfavourable general
3
The data include only consumptions of mineral and spring waters while packaged waters intended for human
consumption are instead excluded.
80
economic situation that can induce consumers towards more cautious purchasing behaviour,
and the increasing diffusion of campaigns in favour of the use of tap water.
Despite the mentioned decrease Italy remains however the leader among the European
countries even if it must be noticed how, with respect to these lasts, in view of higher
consumptions of bottled water, lower consumptions of other packaged soft drinks are instead
registered. Therefore it seems that the high consumptions of bottled water in Italy penalise
consumptions of other packaged soft drinks rather than those of tap water (Bevitalia, 2009).
Table 1.6 furthermore allows to recognize how the major part of these high consumptions
(around 79%) takes place through the utilisation of water packaged in polyethylene
terephtalate (PET) one-way bottles, which represents an highly wasteful practice. In particular
73% of the overall volume is consumed in big format bottles (1.5 and 2 litres) which are
estimated to be mainly employed at domestic level.
The use of glass bottles represents instead the only 18% of the overall consumptions and is
estimated to be mainly associated to the HORECA4 channel (either in one way or refillable
form) and, in minor part, to the domestic door-to-door delivering channel (generally in
refillable form) (Bevitalia, 2009).
Table 1.6: Consumptions of bottled water per typology of packaging in Italy for the year 20085 (Elaboration on
data from Bevitalia (2009))
Typology of packaging
Millions litres litres/inhab/y
PET1 bottles – 2 litres
576.4
9.7
PET bottles – 1.5 litres
7,833.6
131.9
PET bottles – single serve (≤ 0.5 litres)
690
11.6
PET bottles - total
9,100
153.2
Glass bottles
2,070
34.9
PC2 and PET jugs, bio-bottles, brick
350
5.9
Total
11,520
194.0
(1) PET: Polyethylene terephtalate
(2) PC: Polycarbonate
%
5
68
6
79
18
3
100
Leaving aside personal tastes, the reasons of such a massive consumption of bottled (mineral)
water seems to be associated, at a first instance, with the persistent advertising aimed at
persuading consumers that drinking mineral water is the best option (Temporelli and
Cassinelli, 2005; Martinelli, 2010). Through a more comprehensive look it is also possible to
recognize how another factor could be represented by the lack of confidence towards the
4
HORECA: Hotellerie, Restaurants and Cafés (or Catering)
The data include all packaged waters: mineral and spring waters as well as waters intended for human
consumption.
5
81
quality of tap water. Last available data (ISTAT, 2010b) reveal indeed that, on average,
32.2% of the Italian citizens do not rely on drinking tap water. Despite this value has reduced
with respect to past years (it amounted to 44.7% in 2000 and to 35.8% in 2005), meaning that
people are changing their attitude towards such a practice, it appears to be still significant.
From a further statistical survey reported by Temporelli and Cassinelli (2005), which has
analyzed the reasons that induce consumers to prefer drinking of mineral water with respect to
tap water (figure 1.4), it emerges that, though being present for 36.5% the fear of its pollution,
the major reason that induce consumers not to drink tap water is its unpleasant taste (46.4%).
Unpleasant taste
46.4
36.5
Fear of pollution
Other
8.7
Habit
2.6
Water scarcity
2.3
Health reasons
1.9
Water too much heavy
1
Prefer sparkling water
0.6
0
5
10
15
20
25
30
35
40
45
50
%
Figure 1.4: Results of a statistical survey on the reasons that induce consumers to prefer drinking of mineral
water with respect to tap water (Adapted from Temporelli and Cassinelli, 2005)
Unpleasant taste and smell of water are mainly caused by the use, during its purification, of
chlorine based disinfectant, which are generally also dosed before the introduction of water
into the distribution network to ensure persistence of the respective bactericidal action.
Moreover the general organoleptic characteristics of water can be subject to worsening during
its permanence within the distribution network itself which, because of its general poor level
of maintenance, could favour water contamination by allowing the infiltration of soil particles
or for the detaching of calcareous deposits.
However, if the reasons concerning the poor organoleptic characteristics of tap water are
comprehensible when adduced to justify the preference of drinking bottled (mineral) water,
not as much comprehensible are the lack of confidence in drinking tap water or the fear that it
can be polluted, questioning therefore its drinkability.
82
Drinkability of tap water (intended as microbiological purity and absence of harmful
substances) has indeed to be assured by law, which at Italian level is represented by the
Legislative Decree 31/2001, then integrated by the Legislative Decree 27/2002, that
implements the European Directive 98/83/EC concerning the quality of waters intended for
human consumption, whether they are supplied from a distribution network or in any
typology of bottles/containers.
In particular the Decree establishes that waters intended for human consumption have to be
wholesome and clean and to this end they have to be free from any microorganism and
parasite and from any substance in number or concentration able to constitute a potential
danger to human health. Moreover they have to respect minimum requirements on:

2 microbiological parameters (5 if water is offered for sale in bottles or containers);

28 chemical parameters concerning undesirable and toxic elements;

21 indicator parameters concerning characterizing elements; and

2 radioactivity parameters.
In the case of water supplied from a distribution network these parameters have to be
respected at the point at which they emerges from taps that are normally used for human
consumption. The Decree also establishes that either internal or external monitoring have to
be performed to verify that water intended for human consumption actually respects the above
mentioned parameters. The former are carried out by the managers of the integrated water
service while the latter by the local health corporations.
On these bases it is therefore possible to recognize that public network water can be
considered safe, reliable, wholesome and clean, just because its content of microorganism and
of harmful substances has to be rigorously monitored (Temporelli and Cassinelli, 2005).
The fact however remains that in some localities the unpleasant organoleptic characteristics of
the supplied water actually represent a not negligible problem which can discourage
consumers from drinking tap water. In these cases an attempt that could be carried out for the
improvement of such characteristics could consist in the utilisation of proper equipments
aimed at refining water quality at domestic level by removing unpleasant taste and smell and
that also act as an active barrier against possible residual traces of pollutants. They are
commonly named as domestic depurators even if, rigorously, the Ministerial Decree 443/90,
which establishes the requirements that such typologies of equipments have to comply with,
forbids to promote or to commercialize them by employing this terminology since they can
83
only deal with already drinkable water. For short, in this study, they will be however indicated
as domestic depurators (or domestic purifiers).
Several typologies of equipments are available which, according to the mentioned decree, are
mainly represented by ion exchange softeners, reverse osmosis systems, mechanical filters,
activated carbon filters and composite structure filters. These techniques are individually
applied or combined together in a unique device. One exception is represented by activated
carbon filters which the decree does not allow to utilise alone because of the documented
risks of bacterial proliferation and of uncontrolled release of micro-pollutants. For this reason
they are required to be integrated with other devices able to eliminate such drawbacks.
It must be finally underlined that the utilisation of these appliances is characterized by some
critical factors (Temporelli and Cassinelli, 2005). First of all the typology of equipment to be
employed is often chosen without taking into account the actual characteristics of the water it
will have to deal with and therefore the parameters that need to be modified, involving the
risk to subject water to excessive or unneeded treatments. An example is represented by the
utilisation of systems based on reverse osmosis which can produce an excessively
demineralised water (with an almost void salt content), that becomes in this way unsuitable
for human consumption. A last important aspect is represented by the periodical maintenance
of the various components of the systems, which has to be correctly carried out in order to
avoid the opposite effect of worsen water quality. In particular, according to the already
mentioned risk of bacterial proliferation and uncontrolled release of pollutants, the respect of
the right substitution frequency of activated carbon and composite filters results to be of
essential importance.
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CHAPTER 2
LCA AND WASTE PREVENTION
2.1 Introduction to LCA
Life cycle assessment (LCA) is included in that group of methodological instruments
developed during last years to support the sustainable development of activities through a
preventive approach (Masoni, 2002). It can be considered the evolution of the energetic
analysis developed in the USA at the end of the sixties, when some big industries began to
address their interest towards resources saving and reduction of the emissions into the
environment (Baldo et al., 2008).
From that moment, the level of harmonization and standardization of the methodology has
been improved during the years leading to the development of international standards by ISO
(International Standard Organization) which are at the moment represented by the standards
ISO 14040 (ISO 2006a) and ISO 14044 (ISO 2006b).
According to these lasts, LCA is a tool developed to quantify and analyze the inputs, the
outputs and the associated potential environmental impacts of products or services throughout
their whole life cycle. This encompasses resources extraction and preparation of raw
materials, products manufacturing, their use and their end of life, being it recycling or
disposal. This holistic approach is usually indicate as a from cradle to grave approach and it is
useful to prevent problems shifting from one life cycle stage to another. All the process units
involved in the life cycle of products and services are generally indicated with the term
product systems while inputs and outputs from these process units are termed environmental
burdens (Guinée, 2002; Clift et al., 2000).
An LCA study is generally composed by four major stages which have not to be intended as
strictly separated but rather as part of an iterative process in which the outcomes of a specific
stage can imply a review of the previous ones, as shown in figure 2.1 (ISO, 2006a; ISO
2006b; Guinée, 2002).
86
Chapter 2. LCA and waste prevention
Goal and scope
definition
Inventory analysis
Interpretation
Impact assessment
Figure 2.1: Stages of a life cycle assessment (ISO, 2006a)
1. Goal and scope definition:
it is the stage in which the reasons for carrying out the study, its intended application
and intended audience are firstly declared (goal definition). During scope definition a
description of the product system to be studied and of its function is instead provided,
the system boundaries and the functional unit are defined, as well as the impact
categories to be considered and the impact assessment methodology that will be used.
In this stage also data sources, assumptions and possible limitations are indicated.
To define system boundaries means specify which life cycle stages, process units and
flows of the product system to be studied will be considered in the analysis. The
criteria at the basis of the choice of system boundaries have to be manifested and
justified.
The functional unit is a quantitative measure of the primary function(s) performed by
the product system under study which constitute a basis to which relate the inputs and
the outputs of the process units considered in the system boundaries. Practically the
functional unit indicates “how much” of the primary function(s) fulfilled by a product
system will be considered in the study (Guinée, 2002). It also represents the common
basis upon which different systems performing the same function(s) can be compared.
Only the comparison among functionally equivalent systems is indeed allowed.
Strictly related to the functional unit is the reference flow which is a measure of the
outputs from the given product system, required to fulfil the function expressed by the
functional unit.
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2. Life cycle inventory analysis (LCI):
in this stage all the inputs and the outputs of the process units within the system
boundaries of the product system(s) to be studied are identified and quantified with
respect to the reference flow of the functional unit. Major inputs concern energy and
raw materials while major outputs are represented by airborne emission, waterborne
discharges, soil releases and waste flows. According to the data and the information
that have been possible to collect during the inventory stage, some aspects of the
scope already defined, especially system boundaries, may have to be modified. This
aspect is one of those which give to LCA an iterative character.
3. Life cycle impact assessment (LCIA):
this stage aims at associate the outcomes of the inventory to environmental impacts
potentially caused by the investigated product system. It is composed by six elements
the first three of which are mandatory while the remaining are optional:

selection of impact categories, category indicators and characterization models
(mandatory);

classification (mandatory): the quantitative results of the inventory analysis
(which actually means resource consumptions and emissions), are assigned to
the various impact categories before selected as a function of the impact that
they are expected to generate on the environment;

characterization (mandatory): involve the conversion of the inventory results
assigned to a specific impact category during classification in a common unit
and their subsequent aggregation, within the same impact category, through the
use of characterization factors. In this way a single numerical indicator which
quantifies the potential impact is obtained.

normalization (optional): the impact indicators before calculated are converted
in terms of a common reference unit with the aim to better understand the
relative importance and magnitude of these indicators for the product system(s)
under study.

grouping (optional): impact categories (normalized or not) are aggregated into
homogeneous groups, for instance sorted according to the spatial scale they are
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involved in (global, regional and local) or ranked in a given hierarchy, such as
high, medium and low priority on the basis of different criteria.

weighting: a weighting factor is assigned to each impact indicator on the basis
of its relative importance in order to obtain a unique weighted index
representative of the overall impact of the examined product system(s).
The last three steps are considered as optional by ISO standards because are interested
by subjective choices which could lead to more uncertain and debatable results.
4. Life cycle interpretation:
in this stage the results obtained during the inventory phase are presented and
analyzed in view of the goal and the scope of the assessment. It is also possible to
provide suggestions for the improvement of the investigated product system by
evaluating which life cycle stages or process units give the most important
contribution to the calculated impacts.
If different product systems are compared, the best option is, if possible, identified,
always keeping in mind that all the results must be read in view of the assumptions
and the limitations made in carrying out the study. Performing a sensitivity analysis of
the parameters associated with the most important assumptions or affected by greater
uncertainty is a useful tool to asses the robustness of the results.
2.2 LCA applied to integrated solid waste management systems
As just said besides to products and manufacturing processes, life cycle assessment can be
also applied to services, as the one represented by solid waste management, which is
generally referred to as integrated solid waste management system. Several examples of
practical applications of this tool aimed at the identification of the best environmental
performing waste management option for a given geographical reality are available in the
literature, such as Buttol et. al. (2007) for the district of Bologna or Arena et al. (2003) for the
Campania Region just to cite some. Cleary (2009) has also performed a comparative analysis
of the most important reviewed LCA studies applied to integrated waste management
systems.
The use of LCA for this purpose stems from the consideration that the validity of the
hierarchy of conventional waste treatment options pointed out by the European legislation
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(paragraph 1.1) should be evaluated case by case and not to be seen as a rigid prescription,
because the environmental performances of a waste management scheme are function of
geographic, economic, social and technological factors. A waste treatment option that is lower
down in the hierarchy could be therefore preferred to an option that is higher up if it causes
lower environmental impacts in a specific situation (Buttol et al., 2007). For instance, the
waste hierarchy is of little use when different options are used in combination and can not
account for the wide variety of specific local situations. The best waste management option is
indeed not universal but have to be identified on regional basis as a function of the actual
waste composition, of the actual availability of waste treatment options with the respective
level of technology, as well as of the market size for products derived from the waste
management itself in that specific context (White et al, 1995).
There are however some fundamental differences between waste management and product
LCA that mainly regard functional unit and system boundaries (White et al., 1995; Finnveden,
1999), which will be now briefly described because they also represent two important issues
for the present work.
With regard to the functional unit, in product LCAs it is generally expressed in reference to
the output from the investigated product system. These studies aim at the optimisation of the
environmental performances of a specific product life cycle by identifying its critical points.
The comparison among different product systems which provide, in different manner, the
same function, in order to identify the most environmentally friendly, could be a goal as well.
The function of a waste management system is instead to deal with the waste of a certain area
and therefore the functional unit is defined in terms of the input to the system itself, for
instance as the management of the waste generated in the geographical area under study. The
goal of such studies is generally the comparison of the environmental performances of
different options to handle the waste generated in a given area (White et al., 1995). Often the
functional unit is more specifically defined on a mass basis as, for instance, the management
of 1 tonne or of 1 kg of waste with a given composition representative of the investigated
geographical area (Ekvall et al., 2007).
As far as system boundaries are concerned, ISO standards (ISO, 2006a; 2006b) state that
these have to be established in such a manner that their inputs and outputs are elementary
flows. This means that inputs should be energy or material flows drawn from the environment
90
without any previous human transformation and outputs should be energy or material flows
released into the environment without any further human transformation. In other words,
inputs and outputs to and from the system should be followed from the “cradle” to the
“grave”. This approach is the one generally employed within products LCA unless a deviation
is otherwise justified. Conversely, this is instead typically not done in LCA of waste
management systems, for which the inputs are waste themselves. This is however still
consistent with the LCA methodology if the same amount of waste enters the boundaries of
all the systems to be compared, because this assures that all life cycle stages upstream the
moment in which a product becomes waste can be considered as common among the systems
investigated. They can be therefore excluded from the analysis without affecting the
differential comparison of the performances of such systems. Being generally the functional
unit of these assessments the management of a given amount of waste with a given
composition, which remain the same for all the management options to be compared, the
described approach is that usually followed. This approach is generally termed as the zero
burdens assumption because the waste does not bring any burdens of its previous life cycle
into the waste management system (Ekvall et al., 2007; White et al., 1995; Finnveden, 1999).
This reduction of system boundaries simplifies the assessment and allows it to focalise on the
sole waste treatments (Cleary, 2010b).
The grave of the waste life cycle is instead generally the same for both product and waste
management LCA that is when materials cease to be waste, by becoming an emission to air or
water, an inert material in landfill, or by becoming a useful product by means of a recovery
process (Coleman et al., 2003). The same authors also define waste management oriented
LCA as an horizontal approach because it includes the end of life stage of all products, while
product oriented LCA is defined as a vertical approach because considers the whole life cycle
of a product. They however overlap for the part of the life cycle that the specific product
spends in the waste management system (figure 2.2).
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Product systems
Life cycle stages
1
2
3
n
Raw material
extraction
Manufacturing
Distribution
System boundaries for
traditional product
oriented LCA
(vertical approach)
Use
Waste
management
System boundaries for
traditional waste
management oriented
LCA
(horizontal approach)
Figure 2.2: Illustration of the difference between system boundaries of product oriented LCA (vertical
approach) and waste management oriented LCA (horizontal approach) and their interaction (Adapted from
Coleman et al., 2003)
When dealing with recycling or energy recovery, the multifunctionality of these processes
remains however an issue that have to be addressed, for instance, by expanding system
boundaries and avoiding in this way the needs of burdens allocation. This generally consists
in crediting to the recycling processes the avoided burdens associated with the virgin
production of the same material, or to the energy recovery processes the avoided generation of
energy from traditional sources. This technique is usually indicated as the avoided burden
approach (Frischknecht et al., 2007).
2.3 LCA and waste prevention
As anticipated one of the goals of this work concerns understanding how it would be possible
to evaluate waste prevention activities in a life cycle perspective and, in particular within
LCA applied to integrated solid waste management systems. Pointing out waste prevention as
the most favourable waste management option is indeed agreeable, nonetheless the actual
environmental sustainability of a preventive measure should be always evaluated by
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employing a life cycle perspective. This allows to go beyond the simple reduction of waste
which alone does not automatically imply to achieve sustainability.
It is firstly worth to notice that Coleman et al. (2003) claim that a waste management oriented
LCA (the horizontal approach) cannot be used to identify how and where waste prevention
can best be achieved because it assumes the waste as given (according to the zero burdens
assumption), while prevention takes place prior to waste generation. Such analyses could at
most assess the consequences of changes in waste composition on the waste management
system, which may arise from waste prevention activities. According to the same authors
there are two requirements for a more sustainable solid waste management that is the
generation of less waste in the first instance, and the subsequent environmentally effective
management of the wastes that are still produced. In this framework, product oriented LCA
(the vertical approach) should be used by product designers and manufacturers to optimise a
specific product life cycle within a given infrastructures system and would be the right tool to
identify where it is possible to achieve waste prevention within that product life cycle or to
identify how it can best be achieved, by comparing different alternative product systems. On
the contrary waste management oriented LCA would be aimed at optimising the
infrastructures system to manage a given amount of waste with a given composition by waste
planners, once that prevention is achieved. It seems therefore that according to these
considerations, waste management oriented LCA should not deal with scenarios handling
different amount of waste.
Also Cleary (2010b) recognizes the meaningful role of product oriented life cycle assessment
in determining the net environmental performances of waste prevention activities, when
utilised to estimate the difference in terms of environmental impacts among different product
systems one generating less waste than the other, for the same amount of functional output
supplied. The best performing product system can be therefore identified through such an
approach and it is possible to evaluate if waste reduction involved by a given product system
is actually associated with environmental sustainability which, we remember, it is not
automatically implied to be achieved for the sole fact that less waste is generated.
All these considerations are of course reasonable and still valid but obviously refer to waste
management oriented LCA how it was originally conceived. On the contrary we have
recognized the potential importance of the availability for waste managers of a unique tool
capable to evaluate the validity of a waste management scheme which, besides the traditional
management options, includes prevention activities. This in particular in view of the fact that
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the last Waste framework Directive 2008/98 EC (European Parliament and Council, 2008), on
the basis of the indications provided by the Thematic Strategy on Waste Prevention and
Recycling (Commission of the European Communities, 2005), urges Member States to
establish waste prevention programmes which can also be integrated within waste
management plans, and that suggests the use of an approach which takes into account the
whole life cycle of products and materials and not only the waste phase. Moreover also
Gheewala (2009), when discussing research opportunities associated with traditional waste
management oriented life cycle assessment, suggests, among the others, the issue concerning
the possibility of including waste prevention activities in such analysis.
Employing such an approach would allow to compare waste management scenarios in which
waste prevention policies are implemented with respect to others in which this has not be
done, to evaluate with respect to which reference scenario waste prevention would results to
be more beneficial in terms of impact reduction, or the combined effect of implementing
prevention activities together with alternative waste management options (such as increasing
or decreasing separated collection). Cleary (2010b) also highlights the possibility that such an
approach would give to evaluate the potential effects of preventing a given typology of waste
on the whole waste management system or rather, also on waste flows not targeted for
prevention. This would be the case, for instance, of some problematic materials such as
polylactic acid, that is known to potentially create, in absence of adequate sorting devices,
contamination problems of other plastic materials, potentially decreasing the recovery
efficiency of the respective recycling process and therefore the benefits associated with these
practices. This could not instead be done through a product oriented life cycle assessment.
In the present study a research was therefore carried out about which methodological aspects
of traditional life cycle assessment applied to solid waste management systems should be
adjusted to account for prevention activities and to evaluate if conceptual LCA models aimed
a this purpose were already available in the literature. Two LCA models will be finally also
proposed within this study.
2.3.1 Adjustments to traditional waste management oriented LCA and literature models
review
An important contribution concerning the major limitations associated with traditional waste
management oriented life cycle assessment is given by Ekvall et al. (2007) which regarding
94
waste prevention recognizes in first instance how a constant mass based functional unit (i.e.
the management of 1 tonne or of 1 kg of waste with a given composition) would explicitly not
allow the comparison among different systems (or scenarios) dealing with different amounts
of waste generated, as those that include prevention activities. Moreover, the comparison of
different systems characterized by a different numerical based functional unit, i.e. the
management of 1 tonne of waste against the management of 800 kg of waste achieved
through waste prevention, would not be allowed because they would be subject to different
functional units, thus violating the requirement of the ISO standards (ISO 2006a, 2006b)
which establish that systems to be compared must be based on the same functional unit
(Cleary, 2010b).
The authors suggest therefore an amendment consisting in the utilisation of a not constant
mass based functional unit such as “the management of the annual quantity of waste
generated in a geographical area”. A consequence of this choice is however that the zero
burdens assumption is (in general) no longer valid because different waste quantities are
generated under different scenarios. The authors conclude thus demanding if studies dealing
with different waste quantities would include the burdens associated with the production of all
the materials that eventually become waste.
Our answer to this claim will be that it is not necessary because, other than impracticable, it
would be misleading. Only a partial integration of the horizontal and the vertical approaches
of figure 2.2 will be instead proposed (see paragraph 2.3.1.2 and 2.3.1.3).
It must be however underlined that if systems dealing with different amount of waste are
compared by adopting the above proposed functional unit, without including at least those
upstream activities which differ among the different systems, the impacts of the system
generating less waste are overestimated compared to the others (Finnveden, 1999). Other than
overestimated, these impacts could be even worse with respect to those of a more waste
generating system if the avoided burden approach is employed to tackle the problem of the
multifunctionality of recycling or energy recovery processes. This approach could indeed
potentially lead to obtain negative values of the impact indicators such as, for instance, in
Rigamonti et al. (2009), and a reduction of the amount of waste to be treated would actually
translates in lower environmental benefits, which would be a paradoxical conclusion.
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2.3.1.1 The WasteMAP LCA model
One first very recently proposed model addressing the issue of the integration of waste
prevention activities in waste management oriented LCA is found in the literature: the
WasteMAP (Waste Management and Prevention) LCA model proposed by Cleary (2010b). It
is conceptually quite complicated and will be now briefly described.
This model is an hybridisation of both traditional product and waste management oriented
LCA and is mainly conceived to deal with prevention activities which take place through
dematerialization. As described in paragraph 1.2, these activities consist in substituting the
service provided by a certain product system (here the target product system - TPS) with that
provided by a less waste generating one (here the alternative product system - APS6), without
affecting the amount of service provided to the consumers. The WasteMAP LCA model, just
on this basis, considers indeed waste prevention activities which involve dematerialization as
functionally equivalent to the other traditional waste treatment options. Always on the same
basis, the functional equivalence of preventive and not preventive scenarios is also ensured.
Without this equivalence, at least rigorously, they could not otherwise be compared. This
functional equivalence is assured by the introduction of a secondary functional unit as will be
better explained in this paragraph. Prevention activities involving reduced consumption are
instead not considered functionally equivalent with conventional waste treatments because a
waste treatment does not affect the magnitude of the service supplied to the population. The
respective preventive scenarios cannot therefore be considered functionally equivalent to a
reference one and it is not possible to define a secondary functional unit.
Direct consequence of the functional equivalence is that the amount of (potentially generated)
waste managed through prevention activities added to that managed through conventional
treatments is therefore considered to be the same for all the scenarios to be compared.
Functional units
The model is based upon two functional units: a primary functional unit (PFU) and a
secondary functional unit. The primary functional unit ensures that a fixed amount of
(potentially generated) waste is managed under each scenario and is defined as:
“the amount (mass or volume) of material addressed by the municipal solid waste
management system on an annual basis”.
6
Originally named as Alternate Product System by the author.
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In our opinion a more proper reformulation could be for instance: “the management of the
annual amount of waste potentially produced in a given geographical area (or by one its
inhabitant)”, definition that will be employed in the practical application of chapter 3.
The primary functional unit is the same for all the compared scenarios and is equal to the sum
of an upstream primary functional unit (UPFU) and a downstream primary functional unit
(DPFU). The UPFU is defined as “the net amount of material left out of the waste
management system due to waste prevention activities” while the DPFU “tracks the amount
of municipal solid waste collected and treated under each scenario”. This subdivision seems
to be quite unclear and apparently not useful but it is required because the model is actually a
composition of different LCAs as will be better detailed during its practical application
(chapter 3).
The secondary functional unit instead aims at guaranteeing the functional equivalence of
scenarios to be compared assuring that the same level of services is supplied to the citizens of
the region under study by both the target product system and the alternative product system.
For instance, the secondary functional unit could quantify the amount of drinking water that
have to be supplied to the citizens of the region under study for one year: this has to be the
same for each examined scenario, independently from the product system considered to
deliver the service (i.e. bottled water or tap water).
System boundaries
Being the WasteMAP LCA an hybrid model of waste management and product oriented LCA,
also its system boundaries own characteristics drawn from both these typologies of analysis,
as showed in figure 2.3 in reference to a scenario in which one prevention activity is
undertaken.
In particular, the traditional system boundaries of waste management oriented life cycle
assessment, which encompass all the conventional process units of the end of life stage of all
the waste streams entering the waste management system itself (collection, possible sorting,
recycling, biological and thermal treatments and landfilling) represent the downstream
components of the system boundaries of the whole system. These traditional boundaries are
then partially expanded in order to include the upstream life cycle processes (raw material
extraction and preparation, product manufacturing, distribution and use) of those product
systems affected by waste prevention activities: the target product system(s) and the
alternative product system(s). The typology or magnitude of these processes indeed vary
97
among the scenarios to be compared and they have therefore to be included in the system
boundaries, even if the same amount of potentially generated waste is managed in all
scenarios. The zero burdens assumption is instead maintained for those product systems
unaffected by waste prevention. The different widths through which the target product system
and the alternative product system are depicted in figure 2.3 represents the implicit
requirement that the amount of waste removed from the waste management system must be
greater than the amount added to it.
One sophistry is that the expansion of traditionally adopted upstream system boundaries
performed by the WasteMAP LCA model seems also to be justifiable by the fact that the
compared systems are multifunctional: both the functions of managing (potentially) generated
waste and of supplying the service of the systems affected by waste prevention are instead
performed. This multifunctionality can be dealt with, for instance, through system boundaries
expansion, as in the case of the WasteMAP LCA. In particular the avoided burdens approach
is adopted, as will be better detailed in the rest of the paragraph.
Figure 2.3: Representation of the system boundaries considered by the WasteMAP LCA model for a waste
prevention scenario including one prevention activities taking place through dematerialization (Adapted from
Cleary (2010b))
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Burdens/impacts calculation
The WasteMAP LCA model foresees two typologies of procedures to calculate environmental
burdens or impacts associated with a preventive scenario according to the fact that the
implementation of prevention activities has also effects on the treatments of the wastes
remaining in the system or not. This is for example the already mentioned case of preventing
the generation of problematic materials such as polylactic acid which should bear some
benefits to the recycling process of the other conventional plastic wastes.
We report here the case in which the treatments of the waste remaining in the system is
affected by prevention activities, that has however a general validity and can be applied for
both possible cases. Moreover the number of calculations that should be carried out with both
the methods appears of the same magnitude and it seems therefore that no specific advantages
are associated with choosing a method rather than the other.
First of all, the environmental burdens/impacts of a baseline scenario (BLS) in which no
waste prevention activities are undertaken, can be calculated through a traditional waste
management oriented LCA of a reference waste management system (REF WMS7) which
deals with the whole amount of potentially generated waste through conventional treatments.
For the system is therefore valid the relation PFU=DPFU since UPFU=0.
The burdens/impacts of a preventive scenario (WPS8) implementing n prevention activities
can be instead calculated through the equation 2.1:
n
WPS  DOWN WMS 
 UpTPSWPA 
WPA 1
n
 UpAPS
WPA
(2.1)
WPA 1
where:

WPS represents a generic environmental burden/impact of a waste prevention
scenario;

DOWN WMS9 represents a generic burden/impact of the waste management system
that treats the residual amount of waste that still have to be managed after the
implementation of n waste prevention activities. These can be calculated through a
traditional waste management oriented LCA which practically utilises the DPFU as
7
Originally indicated only as REF by the author.
Originally indicated as WMP by the author.
9
Originally indicated only as DOWN by the auhor.
8
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functional unit. This aspect is not so well defined within the original paper of Cleary,
but was clarified thanks to a personal communication with the author (Cleary, 2010a);

UpTPSWPA represents a generic burden/impact of the upstream life cycles of the target
product system(s) which can be calculated by conducting a product oriented LCA that
utilises as functional unit the secondary functional unit;

UpAPSWPA represents a generic burden/impact of the upstream life cycles of the
alternative product system(s) which can be calculated with the same procedure of that
pertaining to the target product system.
On the basis of this equation appears to be clear how to define the burdens/impacts of a
preventive scenario, three separate analyses have actually to be carried out. It also emerges
the fact that the avoided burdens approach is employed to deal with the systems
multifunctionality. In particular, the burdens associated with the secondary function of
supplying a service through the alternative product system are charged to the preventive
scenario while those associated with the no longer need of supplying the same service through
the targeted product system are discounted to the same scenario. These burdens were instead
not considered within the baseline scenario which in this way is made comparable with the
preventing one. Figure 3.4 graphically clarifies which scenarios are intended to be compared,
which systems are involved and how the respective impacts have to be calculated.
WasteMAP LCA (avoided burden approach)
BASELINE SCENARIO
REF WMS
VS
n
DOWN WMS
-  UpTPS
i 1
n
i
+  UpAPS
i
i 1
Figure 2.4: Scenarios to be compared when utilising the avoided burden approach version of the WasteMAP
LCA model: sub-systems included and procedure for the calculation of the respective impacts
Cleary also briefly suggests that instead of the avoided burden approach also the cut-off
approach could be employed. This would translate in assigning the burdens of the upstream
life cycle processes of the target product system(s) to the not preventive waste management
system, instead of subtract them from the preventive waste management system. In this way
the baseline and the preventive scenarios could be analysed separately. It is possible to
recognize that the burdens/impacts of a baseline scenario should therefore be calculated as:
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n
BLS  REF WMS 
 UpTPS
(2.2)
WPA
WPA 1
while those of a preventive scenario should instead be calculated as:
n
WPS  DOWN WMS 
 UpAPS
(2.3)
WPA
WPA 1
It appears however to be clear how the results of the differential comparison between a
baseline and a preventive scenario would remain the same with both the approaches. Figure
3.4 graphically clarifies which scenarios are intended to be compared, which systems are
involved and how the respective impacts have to be calculated.
WasteMAP LCA (cut-off approach)
BASELINE SCENARIO
VS
n
REF WMS
+  UpTPS
i
n
DOWN WMS
i 1
+  UpAPS
i
i 1
Figure 2.5: Scenarios to be compared when utilising the cut-off approach version of the WasteMAP LCA model:
sub-systems included and procedure for the calculation of the respective impacts
It seems finally to emerge from the paper of Cleary that the WasteMAP LCA model could
also deal with waste prevention activities taking place through reduced consumptions but in
these cases preventive scenarios and baseline scenarios cannot be considered as functionally
equivalent and their comparison would not be rigorously allowed. In these cases the analysis
should be carried out without the definition of the secondary functional unit and by not
including the impacts of any alternative product systems.
There is however a case in which scenarios implementing prevention activities involving
reduced consumptions can be compared without the need to define a secondary functional
unit to ensure their functional equivalence, that is the case in which the target product system
supplies a service which is considered unwanted by certain citizens such as those provided by
the delivering of unaddressed advertising material (junk mail).
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From a theoretical point of view the WasteMAP LCA model seems to be relatively complex
and this is probably due to the fact that the author aimed at proposing a model strongly
consistent with ISO standards. Anyway its practical applicability will be investigated in
chapter 3.
A last consideration can be done concerning the difficulties potentially involved in the
definition of the secondary functional unit, which could be a not so simple task for all the
typologies of prevention activities.
2.3.1.2 First proposal of a model: the Integrated Scenarios Waste Prevention Model
(ISWPM)
Once recognized the complexity of the WasteMAP LCA model we have tried to carry out
some first adjustments to it in order to simplify its applicability. This also on the basis of the
work of Gallo (2009) in which an approach to deal with waste prevention activities within the
framework of waste management oriented LCA is proposed.
In this work the author always considers waste prevention as part of the service provided by
the waste management system, in which it can or cannot be included. The functional unit
assumed is:
“the integrated management of the annual amount of waste produced by a city, in which a
prevention programme consisting in different measures will be implemented”.
In this way, as in the WasteMAP LCA, the amount of waste to be managed in all the
compared systems is always the same even if within preventive scenarios a certain amount is
managed through prevention.
An upstream system boundaries expansion is after proposed by the author according to the
fact that waste prevention is assumed to avoid the manufacturing of the products targeted for
prevention. The manufacturing processes of the prevented product are therefore included in
the system boundaries and the respective avoided burdens are credited to the system. A
representation of the major processes to be included in the system boundaries according to
Gallo (2009) is given in figure 2.6.
No explicit mention is made with regard to two important aspects. The first concerns if
besides the manufacturing process of the prevented waste also other associated upstream life
cycle processes such as transportations and use are considered to be avoided. The second
instead regards if additional burdens associated with upstream life cycle processes of the
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product system in case required to ensure the supplying of the same service previously
provided by the prevented product are accounted for. This was referred to as the alternative
product system by Cleary with regard to prevention activities taking place through
dematerialization. However it seems that when analyzing the introduction of a refilling
system for beverage bottles as preventive activity, the burdens associated with increased
transportations and with bottles washing are implicitly included by the author as well as the
transportation within the baseline disposable bottles system are considered.
Figure 2.6: Representation of the system boundaries considered by Gallo (2009) for a waste management
system including waste prevention activities (Adapted from Gallo (2009))
In our opinion as well as the model of Cleary can be simplified, also the one of Gallo can be
improved and we have therefore tried to do this by proposing a new model which takes
suggestion from those of both the mentioned authors.
First of all we agree with considering waste prevention as part of the service provided by the
waste management system how both the authors made, but without the needs of introducing
all the aspects associated with the functional equivalence and the secondary functional unit
considered by Cleary. According to the Waste Framework Directive 2008/98 EC (European
Parliament and Council, 2008) and to the European waste policy in general, waste prevention
is part of the waste hierarchy and therefore it can be considered as an indirect option to deal
with wastes.
Given this, the functional unit can be more precisely defined as:
103
“the integrated management of the annual amount of waste potentially produced in a given
geographical area (or by one its inhabitant), in which waste prevention activities are
undertaken”.
The word potentially is here introduced in order to highlight the fact that a certain amount of
waste would not actually be generated if prevention activities was undertaken.
In such a manner the amount of potentially generated waste to be managed is the same in all
the possible considered scenarios and their comparison is therefore allowed because they are
based on the same functional unit.
Waste prevention can then be considered as a waste management option (or process) that
avoids the production of the prevented waste as well as the associated ancillary upstream
processes or, in other words, the supplying of a service through the target product system(s)
and the occurring of the respective upstream life cycle processes. On the other hand, in the
case in which waste prevention takes place through dematerialization, it implies the supplying
of the same amount of service through the alternative product system(s) and the occurring of
the respective upstream life cycle processes. When a waste prevention scenario has to be
analysed the traditional system boundaries of waste management oriented LCA are therefore
expanded to include these upstream processes. A simplified representation is given in figure
2.7 either for a baseline or for a waste prevention scenario.
For the practical impacts calculation, the avoided burdens associated with the avoided
upstream life cycle processes of the prevented waste are credited to the preventive waste
management system, while those associated with the possible alternative product system are
charged to the system itself. These lasts would not be included if waste prevention took place
through reduced consumption. The procedures for the calculation of the impacts of a baseline
and of a waste prevention scenario are graphically illustrated in figure 2.8 by also highlighting
the systems included in the scenarios to be compared.
As showed in figure 2.7 possible waste diversion activities such as home composting, are
considered to be part of the boundaries of the traditional waste management system because
they do not imply to achieve a strictly prevention but only a reduction of the waste to be
collected. However possible benefits associated with reduced collection, transportation and
waste bags production can be accounted for if these processes was included in the system.
The WasteMAP LCA model is in this way simplified with regard to the no longer required
need to define a secondary functional unit, while the model proposed by Gallo is improved
104
introducing the concepts of target product system and alternative product system proposed by
Cleary.
The model is named as Integrated Scenarios Waste Prevention Model (ISWPM), since both
the product systems interested by waste prevention are considered at the level of the
preventive scenario, even if the target product system rather belongs to the not preventive
scenario.
105
BASELINE SCENARIO
Potentially generated municipal solid waste = Input waste
REFERENCE (REF) WMS
Conventional waste
management processes:
Collection/transportation
Sorting
Recycling
Thermal treatment
Biological treatment
Landfilling
Domestic treatments:
Home composting
Grass-cycling
.........
Compensative processes:
•Virgin material production
•Energy generation
•Peat and fertilizers production
VS
Avoided upstream life
target product system(s)
(UpTPS1,n)
Additional upstream life
alternative product system(s)
(UpAPS1,n)
Potentially generated municipal solid waste > Input waste
Conventional waste
Sorting
Recycling
Landfilling
Home composting
Grass-cycling
.........
Figure 2.7: Simplified representation of the system boundaries considered by the Integrated Scenarios Waste
Prevention Model for a baseline and a waste prevention scenario including prevention activities taking place
through dematerialization
106
ISWPM
BASELINE SCENARIO
REF WMS
VS
n
n
PREV WMS   UpTPS i   UpAPS i
i 1
i 1
Figure 2.8: Procedure for the calculation of the impacts of the scenarios to be compared through the Integrated
Scenarios Waste Prevention Model and respective included sub-systems
2.3.1.3 Second proposal of a model: the Separate Scenarios Waste Prevention Model
(SSWPM)
Either the WasteMAP LCA model or the ISWP model previously proposed do not allow to
totally separate the burdens/impacts actually pertaining to a preventive scenario and to a not
preventive one. Those of the target product system are indeed accounted for in the preventive
scenario together with those of the alternative product system. Such a separation could at
most be maintained by utilising the cut-off approach version of the equations characterizing
the WasteMAP LCA model but this imply to deal with its relative complexity.
For this reason we have recognized the potential need of the availability of a model
conceptually simpler to apply than the WasteMAP LCA and able to ensure this systems
separation. For this reason we have chosen to name this model as Separate Scenarios Waste
Prevention Model (SSWPM).
In order to do this we have taken into account the suggestion of Ekvall (2007) and to consider
therefore as functional unit:
“the management of the annual amount of waste produced in a given geographical area (or
by one its inhabitant)”.
This amount is hence assumed to vary according to the scenario as a consequence of the
introduction of prevention activities but the comparison between different scenarios dealing
with a different quantity of waste is allowed since this is not a mass based functional unit.
In this case there is no need to consider waste prevention as part of the service provided by
the integrated waste management system, even if actually it is.
A direct consequence of the choice of such a functional unit is therefore the no longer general
validity of the zero burdens assumption because different amounts of waste enter in different
systems to be compared. At least those upstream life cycle processes which differs among the
107
systems for their typology or magnitude should be therefore included in the system
boundaries. A complete abandonment of the zero burdens assumptions is instead not
necessary because, other than impracticable, it would be misleading. Adopting again the
terminology proposed by Cleary for waste prevention activities taking place through
dematerialization, the upstream life cycle processes to be included would be those belonging
to the target product system(s) for not preventive scenarios and those of the alternative
product system(s) for preventive scenarios. These lasts would however not to be included if a
prevention activity took place through reduced consumption. From another point of view this
approach can be seen as a partial integration of the vertical and the horizontal approach
typical, respectively, of product oriented LCA and waste management oriented LCA. Only
those product life cycles affected by waste prevention are however included.
A simplified representation of the system boundaries considered by this model for both a
baseline and a waste prevention scenario is given in figure 2.9.
A direct consequence of this upstream system boundaries expansion is the fact that the
potential benefits and loads associated with the implementation of a prevention activity are
automatically accounted for when a preventive and a not preventive scenario are compared.
The procedure for the calculation of the impacts of the mentioned scenarios is graphically
illustrated in figure 2.10 by also highlighting the systems included in the scenarios to be
compared.
108
BASELINE SCENARIO
Upstream life cycle processes
of the target product system(s)
(UpTPS1,n)
REFERENCE (REF) WMS
Conventional waste
Sorting
Recycling
Landfilling
Home composting
Grass-cycling
.........
VS
Upstream life cycle processes of
the alternative product system(s)
(UpAPS1,n)
Conventional waste
Sorting
Recycling
Landfilling
Home composting
Grass-cycling
.........
Figure 2.9: Simplified representation of the system boundaries considered by the Separate Scenarios Waste
Prevention Model for a baseline and a waste prevention scenario including prevention activities taking place
through dematerialization
109
SSWPM
BASELINE SCENARIO
n
REF WMS   UpTPS i
VS
i 1
n
PREV WMS   UpAPS i
i 1
Figure 2.10: Procedure for the calculation of the impacts of the scenarios to be compared through the Separate
Scenarios Waste Prevention Model and respective included sub-systems
2.3.2 Final remarks
The most important features of the three discussed LCA models (WasteMAP LCA, ISWPM
and SSWPM) are summarised for clarity in table 2.1.
It is worth to underline that despite these models are built up on the basis of different
theoretical assumptions, they are however expected to lead to similar results. All of them are
indeed based on the principle of taking into account, besides the burdens/impacts associated
with traditional waste treatments, also the environmental benefits and loads potentially
associated with the substitution of the consumption of the service provided by a given product
system with that of an analogous service provided by a less waste generating system, or with
the only diminishing of the consumption of the service provided by a certain product system.
A final common remark concerns instead data availability. In order to include upstream life
cycle processes in the assessment it is indeed potentially required to collect a greater amount
of data and information concerning their operation, besides those pertaining to conventional
waste treatment processes. The knowledge of the former could be however beyond waste
managers competence and therefore the performing of such a typology of analysis could
require higher investment of time and resources in general, with respect to a traditional waste
management oriented life cycle assessment.
110
Table 2.1: Major features of the LCA models discussed in this chapter
FEATURES\
MODELS
WatseMAP LCA
(Cleary, 2010b)
ISWPM
SSWPM
(Primary)
functional
unit
“the management of the
annual amount of waste
potentially produced in a
given geographical area (or
by one its inhabitant)”
(leads the overall analysisthe amount of waste to be
managed is the same in all
scenarios)
“the integrated management
of the annual amount of waste
potentially produced in a
given geographical area (or
by one its inhabitant), in
which waste prevention
activities are undertaken”.
(the amount of waste to be
scenarios)
annual amount of waste
produced in a given
geographical area (or by
one its inhabitant)”
(the amount is subject to
change between scenarios)
-
-
-
-
part of the service provided by
the WMS1 – is an actual
component of the WMS -
no need to consider waste
prevention as a component
of the WMS
the burdens of TPSs2 are
assigned to the BL4 scenario
and those of APSs2 are
assigned to the WP3 scenario
(are assigned to the system
in which they actually take
place)
Downstream
primary
functional
unit
Secondary
functional
unit
(if required)
Position
of waste
prevention
Approach to
traditional
system
boundaries
expansion
“the collection and
treatment of the annual
amount of waste produced in
a given geographical area
(or by one inhabitant)”
(the amount of waste
collected and treated varies
between scenarios)
Defines the amount of
service(s) that have to be
supplied by the product
system(s) targeted for
prevention and by its/their
less waste generating
substitute(s) to the citizens
of the area under study
functionally equivalent to
conventional waste
management treatments
crediting and charging of the
burdens of TPSs2 and APSs2
to the WP scenario
(avoided burden approach)
Exists also a variant which
apply the cut-off approach
to the WP3 scenario
(1) WMS: Waste management system
(2) TPS / APS: Target product system / Alternate product system
(3) WP: Waste prevention
(4) BL: Baseline
CHAPTER 3
MODELS COMPARISON: A PRACTICAL
APPLICATION
3.1 Introduction
The goal of this chapter is to compare the practical applicability of the WasteMAP LCA
model and of the other two LCA conceptual models proposed in chapter 2. This in order to
evaluate their simplicity of application to a real case study and in which measure the results
are potentially affected by the theoretical assumptions at the basis of the models themselves.
As described in chapter 2 the three models are based on applying, in different manners,
expansion of traditional system boundaries of waste management oriented life cycle
assessment in order to account for the upstream life cycle processes associated with the
product systems affected by waste prevention and of the respective environmental benefits
and loads.
In particular through these models the environmental performances of a baseline scenario in
which no prevention activities are undertaken in the waste management system will be
compared with those of a waste prevention scenario in which the preventive activity “use of
tap water” will be implemented, involving a decrease of the amount of waste entering the
system itself.
This activity generally implies that citizens make use of tap water provided by the public
network and in case further purified by a domestic depurator for drinking purposes, instead of
purchasing bottled water from retailers. This would lead to a reduced amount of plastic and
glass packaging waste entering the waste management system. Utilising the terminology
adopted by Cleary (2010b) this activity takes place through dematerialization since it is
possible to identify both the target product system, associated with the function of bottled
water delivering, and the less waste generating alternative product system, associated with the
function of tap water delivering. The implicit advantage of having chosen such an activity is
also the possibility to define the secondary functional unit required by the WasteMAP LCA
model, in a rather simple way.
112
Chapter 3. Models comparison: a practical application
Only a simplified analysis will be carried out in this chapter because the goal is, as just
specified, the comparison of the models. This means that only secondary data from the most
widespread databases, such as Ecoinvent, will be employed, as well as only the global
warming (GW) impact indicator will be considered as a term of comparison.
The analysis will be supported by the software SimaPro, one of the most wide spread tool
utilised for LCA of any kind of products and services developed by the Dutch company PRè
Consultants.
An hypothetical, but very close to the reality, waste management system that treats the
amount of waste produced within the Lombardia Region will be considered in the analysis as
will be described in detail in the next paragraphs of this chapter.
3.2 Waste generation and composition
3.2.1 Gross waste generation and composition
First of all, in the most general case, the amount of each municipal solid waste fraction
generated in the examined area have to be identified, both for baseline and waste prevention
scenarios.
In the specific case under investigation, waste fractions not interested by prevention can
instead be disregarded because the respective amount remains constant within all the
scenarios to be evaluated without affecting their differential comparison. The total produced
amount of each waste fraction was however defined for completeness and to give an idea of
how one should proceed.
In this simplified analysis the Lombardia Region is assumed to be the reference area, and the
overall amount of each waste fraction annually generated in its territory is defined by
combining the last available data concerning the amounts of source separately collected
fractions and those relative to the compositional analysis of the unsorted residual municipal
waste.
Table 3.1 firstly reports the major streams of waste produced during the year 2007 (the last
for which data were available) in the area under investigation (ISPRA, 2008; ARPA
Lombardia, 2008). An overall waste production of about 5 millions tonnes was registered,
which corresponds to about 512 kg/inhabitant/year, if a regional population of 9,642,406
inhabitants is considered (ISPRA, 2008).
113
We underline that the overall amount of source separately collected waste reported in table
3.1 is calculated by excluding that of possible scraps deriving from the sorting processes of
source separately collected fractions, whose amount is instead included into that of the
residual waste.
Table 3.1: Major streams of municipal waste collected in the Lombardia Region during the year 2007 (ISPRA,
2008)
Waste streams
tonnes kg/inhab/year %
tonnes kg/inhab/year
Unsorted residual waste1
2,346,829
243.4
47.6
4,542,836
471.1
Separately collected waste 2,196,008
227.7
44.5
Waste from road sweeping2 130,856
13.6
2.7
389,424
40.4
Bulky waste to disposal
258,568
26.8
5.2
Total production 4,932,260
511.5 100
(1) Includes scraps deriving from separated collection.
(2) Source: ARPA Lombardia, 2008.
In ISPRA (2008) it is instead possible to find the amount of each single source separately
collected waste fraction, always excluding sorting scraps, which is here reported in table 3.2.
Table 3.2: Amount of source separated fractions collected in the Lombardia Region during the year 2007
(ISPRA, 2008)
Waste fractions
tonnes kg/inhab/year %
Wet organic fraction 382,656
39.7
17.4
Green waste
377,524
39.2
17.2
Paper and board
576,058
59.7
26.2
Glass packaging
352,389
36.5
16.0
Plastic packaging
140,980
14.6
6.4
Wood packaging
156,679
16.2
7.1
Metallic packaging
78,065
8.1
3.6
Aluminium
4,219
0.4
0.2
Textile
25,943
2.7
1.2
WEEE
27,306
2.8
1.2
Bulky waste
51,772
5.4
2.4
Selective collection * 10,170
1.1
0.5
Other
12,247
1.3
0.6
Total 2,196,008
227.7 100
*It encompasses: medicines, containers for toxic and
flammable substances, batteries and accumulators,
varnishes, inks and adhesives, vegetal and mineral oils.
The composition of the unsorted residual waste is instead finally assumed to be sufficiently
well represented by that of the input waste to the Silla 2 waste to energy (WTE) plant sited in
the municipality of Milan, provided by Butera and Turconi (2010). Indeed, the plant mainly
114
treats the residual municipal waste of the municipality of Milan and of other few surrounding
municipalities, so that its input waste composition can be supposed to represent at least that of
the unsorted residual waste generated in the major regional urban centres. Table 3.3 reports
therefore the average composition of the input waste to the mentioned plant and the resulting
amounts of each residual waste fraction assumed to be produced in Lombardia, calculated by
multiplying the percentages provided in the first column of the same table, by the total
amount of produced unsorted residual waste reported in table 3.1 (2,346,829 tonnes).
Table 3.3: Composition of the input waste to the Silla 2 waste to energy plant and relative calculated amount of
each unsorted residual waste fraction assumed to be produced in Lombardia during the year 2007
Fractions
Putrescible organic fraction
Wood, pruning waste
Packaging paper and board
Other paper and board
Glass, inert waste
Plastic packaging
Other plastic
Aluminium
Other metals
Textiles, leather, rubber
Hazardous waste
Diapers
Total
%
tonnes kg/inhab/year
12.6 296,692
30.8
5.9 138,049
14.3
28.7 674,402
69.9
9.4 219,520
22.8
3.9
92,561
9.6
24.1 565,774
58.7
3.5
81,471
8.4
0.8
18,105
1.9
16
38,473
4.0
6.0 140,312
14.6
2.3
54,314
5.6
1.2
27,157
2.8
100 2,346,829
243.4
The total produced amount of each waste fraction can be now therefore calculated by properly
combining and summing up the values of table 3.2 and 3.3 according to the criteria shown in
table 3.4. From these it is then possible to obtain the percentage composition of the gross
waste which is assumed to be produced in the Lombardia Region. The results obtained
through these calculations are reported in table 3.5.
115
Table 3.4: Combination criteria of source separated and residual waste fractions used to define the overall
production of each waste fraction and the resulting gross waste composition for the Lombardia Region for the
year 2007
Gross waste fractions Separately collected fractions Residual waste fractions
Organic
Wet organic fraction
Putrescible organic fraction
Green waste
Green waste
Wood, pruning waste
Packaging paper and board +
Paper and board
Paper and board
Other paper and board
Glass packaging
Glass packaging
Other glass+inert waste
Glass, inert waste
Plastic packaging
Plastic packaging
Plastic packaging
Other plastic
Other plastic
Wood packaging
Wood packaging
Metallic packaging
Metallic packaging
Other metals
Other metals
Aluminium
Aluminium
Aluminium
Textiles
Textiles
Textiles, leather, rubber
Diapers
Diapers
WEEE
WEEE*
Bulky waste
Bulky waste
Bulky waste to disposal
Selective collection
Hazardous waste
Other
Other
Road sweeping
Waste from road sweeping
WEEE: Waste from Electrical and Electronic Equipment.
Table 3.5: Total produced amount of each waste fraction and relative gross waste composition assumed as
reference for the Lombardia Region for the year 2007 and employed for the purposes of this study
Fractions
tonnes kg/inhab/year % kg/inhab/year %
Organic
679,348
70.5
138
123.9
24.2
Green waste
515,573
53.5
10.5
Paper and board
1,469,980
152.4
29.8
Glass packaging
352,389
36.5
7.1
46.1
9.0
Other glass+inert waste 92,561
9.6
1.9
Plastic packaging
706,754
73.3
14.3
81.7
16.0
Other plastic
81,471
8.4
1.7
Wood packaging
156,679
16.2
3.2
Metallic packaging
78,065
8.1
1.6
12.1
2.4
Other metals
38,473
4.0
0.8
Aluminium
22,324
2.3
0.5
Textiles
166,255
17.2
3.4
Diapers
27,157
2.8
0.6
WEEE
27,306
2.8
0.6
Bulky waste
310,340
32.2
6.3
64,484
6.7
1.3
Other
12,247
1.3
0.2
Road sweeping
130,856
13.6
2.7
Total 4,932,261
511.5 100
116
3.2.2 Plastic waste fraction composition
In principle the considered prevention activity could affect the amount of both plastic
(nowadays mainly PET) and glass bottles generated as waste from the consumption of bottled
water. In this simplified analysis we have however assumed that a reduction of the PET
bottles waste stream is involved only. The volume of water delivered through glass bottles
will be anyway recognized to amount only to less than 20%, comprehensive of both domestic
and non domestic consumptions (see table 3.7).
Therefore, since the sole plastic waste stream is going to be reduced, only this one will be
considered in the present analysis, leaving out the remaining ones. A further characterization
of this stream in the major typologies of plastic materials of which it is composed is therefore
necessary to understand their possible destination within the management system.
First of all, the composition of the fraction “plastic packaging” of table 3.5 is assumed to be
the same as the one of the whole amount of plastic packaging sent to recovery by the Corepla
circuit during the year 2007, reported in table 3.6 (Corepla, 2008), while the fraction “other
plastic” of the same table, in the lacking of more precise information is assumed to be an
heterogeneous mixture of various polyolefines (POF).
These assumptions will be however demonstrated not to affect the results of the analysis
because regard a plastic stream that is not going to be reduced within the preventive scenario.
According to the above indicated criteria it is now possible to obtain the amount of each
plastic materials assumed to be produced as waste in the Lombardia Region during 2007, as
reported in table 3.7.
Table 3.6: Composition of the whole amount of plastic packaging waste sent to recovery by the Corepla circuit
for the year 2007 (Corepla, 2008)
Packaging materials
PET containers for liquid (CFL)
HDPE containers for liquid (CFL)
PE film (LDPE)
PET mix /POLYOLEFINES mix
PP/HDPE crates
Total
%
53
17
14
15
1
100
117
Table 3.7: Amount of plastic materials assumed to be produced as waste in Lombardia Region during the year
2007
Plastic waste materials
kg/inhab/year
PET containers for liquid (CFL)
38.6
HDPE containers for liquid (CFL)
12.5
PE film (LDPE)
10.1
POLYOLEFINES (POF) mix
19.6
PP/HDPE crates
0.9
Total
81.7
Since the targeted waste flow of the prevention activity is constituted by PET water bottles, a
quantification of their amount into the waste stream is required, even in order to define the
prevention potential. This is possible by only making an indirect estimate on the basis of
bottled water consumptions data, because a such level of detail is lacking with regard to waste
data.
For this purpose the information reported by Bevitalia (2009) concerning the volume of
packaged water consumed in Italy during the year 2008 by typology of packaging, are firstly
employed to calculate the respective specific consumptions, expressed as litres per inhabitant
per year, as showed in table 3.8, considering an average population for the same year of
59,832,179 inhabitants (ISTAT, 2010a). As it can be seen, a specific consumption of water in
PET bottles equal to 152.1 litres/inhabitant/year is resulted, of which the major part in form of
1.5 litres bottles (86.1%) while those in form of 2 litres and 1.5 litres bottles only amount to
6.3% and 7.6% respectively.
Table 3.8: Volume of packaged water consumed in Italy during the year 2008 by typology of packaging, both in
absolute and specific terms (Elaboration on data from Bevitalia (2009))
Packaged water consumptions - packaging mix – Italy, year 2008
PET bottles - 2 litres
576.4
9.6
PET bottles – 1.5 litres
7,833.6
130.9
PET bottles - single serve (≤ 0.5 litres)
690
11.5
PET bottles - total
9,100
1,52.1
Glass bottles
2,070
34.6
PC* and PET jugs, bio-bottles, brik
350
5.8
Total
11,520
192.5
*PC=Polycarbonate
%
5
68
6
79
18
3
100
% on PET
bottles only
6.3
86.1
7.6
100
By Combining these specific consumptions data with the average masses of the three sizes of
PET bottles belonging to the packaging mix, provided by Federambiente (2010) and reported
118
in table 3.9, it is possible to calculate the specific mass of PET bottles introduced into the
plastic waste stream. According to the calculations reported in table 3.10 an amount of about
3.42 kg/inhabitant/year is resulted.
Table 3.9: Average masses of PET bottles employed in Italy for water delivering (Federambiente, 2010)
PET bottles size Bottles mass
(litres)
(g)
2
33.42
1.5
32.55
0.5
18.06
Table 3.10: Definition of the total amount of PET bottles into the plastic waste stream
PET
bottles size
(litres)
2
1.5
0.5
Total
Specific
consumption
(%)
(litres/inhab/year)
6.3
9.6
86.1
130.9
7.6
11.5
100
152.1
Assumed
(kg/inhab/year)
Share
PET
bottles as waste
(kg/inhab/year)
0.161
2.841
0.417
3.419
3.42
In view of the simplified nature of the present analysis, this value is defined by considering
the only mass of bottles and by neglecting the contributions given by caps, labels and by the
heat-shrink films which constitute the secondary packaging.
The calculated value will be also assumed to be the “best case” prevention potential for the
PET bottles waste fraction despite part of the consumed volume of water considered for its
definition is probably not associated with a domestic consumption, such as that involving 0.5
litres bottles which are widely employed in vending machines. Consumptions occurring in
bigger size bottles (1.5 litres and 2 litres) can be instead quite unequivocally considered to be
of domestic nature. The fact that also the amount of sparkling water is included seems instead
not to be improper since it is possible to obtain sparkling tap water by means of proper
equipments. Finally, it is also probable that not all the volume of water consumed from bottles
would be converted to an equivalent consumptions from the tap or, in other words, a 100%
prevention efficiency would probably not be achieved.
We are however not interested in an absolute accounting of the potential environmental
benefits and loads associated with undertaking this prevention activity but only in models
comparison, which can be fairly carried out also in view of the several assumptions made up
to now.
119
By finally subtracting the above obtained value (3.42 kg/inhab/year) from the whole amount
of the fraction “PET containers for liquid” of table 3.7 and by considering PET bottles as an
independent fraction, it is possible to obtain the definitive amount of each plastic waste
fraction assumed to be produced in the Lombardia Region during the year 2007 and to enter
the waste management system in the baseline scenario for all the explored models. These
results are reported in table 3.11.
Table 3.11: Definitive amount of each plastic waste fraction assumed to be produced in Lombardia during 2007
and to enter the waste management system in the baseline scenario
Plastic waste materials kg/inhab/year
PET bottles
3.42
PET CFL1
35.2
HDPE CFL1
12.5
2
POLYOLEFINES mix
30.6
Total
81.7
(1) CFL=Containers for liquid
(2) The POLYOLEFINES mix fractions also includes the
fractions “PE film (LDPE)” and “PP/HDPE crates” of table 6
3.3 Waste management system description and inventory
The waste management system considered in the study is now described, independently from
any specific scenario, since its features remains unvaried within all the investigated scenarios.
A modern waste management system is chosen. It foresees that the plastic waste is partially
sent, after separated collection, to material recovery for secondary raw material production,
while the residual amount is sent to energy recovery (incineration) in a dedicated waste to
energy plant for electricity and thermal energy generation. The features of the system are
chosen in such a manner to be as much as possible close to the reality.
3.3.1 Collection efficiencies
On the basis of the information provided in Corepla (2010) a separated collection efficiency
of about 77% is firstly estimated for PET bottles, PET containers and HDPE containers. On
an amount of PET and HDPE containers for liquid introduced in the Italian market equal to
303,744 tonnes, about 233,661 tonnes were indeed actually separately collected and sent to
recovery during the year 2009 by Corepla. With regard to the polyolefines mix, we have
instead assumed a separated collection efficiency equal to the percentage of plastic packaging
120
materials separately collected during the year 2009 with respect to their whole amount
introduced in the market in the same year, that is equal to about 33%, as reported in the same
source. Table 3.12 summarises these efficiencies.
Table 3.12: Separated collection efficiencies considered for the plastic materials constituting the waste flow
Plastic waste materials Separated collection efficiency
PET bottles
77%
PET CFL
77%
HDPE CFL
77%
POLYOLEFINES mix
33%
The processes of waste collection as well as other transportation stages potentially occurring
within the system are not considered in the present analysis because they appear to be highly
dependent from local conditions (Rigamonti and Grosso, 2009).
3.3.2 Materials selection and recovery
After separated collection, plastic is sent to selection, a process in which the plastic waste
flow is separated from extraneous materials. The further subdivision of the remaining flow in
the various typologies of polymers of which it is composed will be instead considered to be
carried out nearby the recovery facility. Selection efficiency can vary as a function of the
collection method adopted, such as mono-material door to door collection or multi-material
collection through a bring system. Considering the way in which the plastic composition has
been determined it is chosen to assume a 100% selection efficiency, since the various
amounts of materials composing the plastic waste flow do not account for possible impurities.
The burdens associated with the selection stage are however considered, and modelled with
the data provided in Rigamonti and Grosso (2009) reported in table 3.13 in terms of energy
and fuel consumptions.
Table 3.13: Energy consumptions for the plastic selection process (Rigamonti and Grosso, 2009)
Energy
Diesel
kWh/t input plastic MJ/t input plastic
26.6
84
The selected plastic flow is then sent to a recovery facility where it is firstly separated in the
major typologies of polymeric materials of which it is composed that are PET containers,
121
HDPE containers and a selected mixture of polyolefines. These materials are then routed to
three dedicated treatment lines which carry out the actual recovery process, producing,
respectively, PET granules, HDPE granules and profiled bars made from polyolefines.
The overall recovery processes of HDPE containers and of polyolefines mix, are assumed to
have the recovery efficiencies reported in Rigamonti and Grosso (2009) and equal to 90% and
60% respectively. PET bottles and PET containers are instead assumed to be recovered with
an overall 80% efficiency, as reported in Li et al. (2010). This values is indeed slightly greater
than the one specified by the previous authors (75.5%). Table 3.14 summarises these recovery
efficiencies.
Table 3.14: Recovery efficiencies considered for the recovery processes of the plastic materials constituting the
waste flow
Plastic waste materials Recovery efficiency
PET bottles
80%
PET CFL
80%
HDPE CFL
90%
POLYOLEFINES mix
60%
Scraps deriving from the recovery processes are finally sent to incineration for energy
recovery.
The burdens associated with recovery processes are modelled in a life cycle perspective
through the data provided in Rigamonti and Grosso (2009) and reported in table 3.15.
Table 3.15: Energy and materials consumptions for PET, HDPE and POF mix recovery processes
Electricity
Methane
Electricity
Water
NaOH
(reprocessing)
(as heat)
(extruder)
kWh/t R-PET
MJ/t R-PET
kWh/t R-PET litres/t R-PET kg/t R-PET
PET recovery
311
2699
125
2960
3
Electricity
Methane
Electricity
Water
(reprocessing)
(as heat)
(extruder)
kWh/t R-HDPE MJ/t R-HDPE kWh/t R-HDPE litres/t R-HDPE
HDPE recovery
379
650
125
1780
Electricity
Methane
Electricity
Water
(reprocessing)
(as heat)
(extruder)
kWh/t R-mix
MJ/t R-mix
kWh/t R-mix
litres/t R-mix
POF mix recovery
381
650
200
1780
To deal with the multifunctionality of the recovery processes which, besides to perform the
function of managing a waste also supply a secondary raw material, a system expansion is
performed through the avoided burdens approach (paragraph 2.2). In particular, recovery of
122
PET and HDPE is supposed to avoid the production of virgin PET and HDPE granules.
Polyolefines profiled bar can be employed as urban furniture components in substitution of
wood and, therefore, the avoided production of wood planks is considered to be associated
with polyolefines recovery. How suggested in Rigamonti and Grosso (2009), in order to
account for quality reduction of the recovered material with respect to the virgin one, a
substitution factor of 1:0.81 is introduced for PET and HDPE. It means that 1 kg of secondary
raw material can substitute only 0.81 kg of virgin raw material. For the polyolefines mixture a
substitution factor of 1:1 is instead considered, since it is supposed that 1 m3 of profiled bar
can substitute 1 m3 of wood planks, how reported by the same authors.
The described processes are modelled in SimaPro creating four modules that account for the
respective burdens, in particular:
-
Plastic selection: it considers all the energy inputs required for the selection of 1 tonne
of plastic, as reported in table 3.13;
-
PET granules from PET bottles/containers recovery;
-
HDPE granules from containers recovery;
-
Profiled bar from POF mix recovery;
This last three modules instead account for the direct materials and energy inputs associated
with the production of 1 tonne of recovered PET, HDPE and polyolefines profiled bars
respectively, on the basis of the data showed in table 3.15. They also include the
compensatory processes associated with the avoided production of virgin PET and HDPE
granules and of virgin wood planks respectively, on the basis of the substitution factors
described above. The Plastic incineration module, described in the next paragraph 3.3.3, is
recalled in each recovery module to account for the burdens associated with the incineration
of the scraps deriving from the same recovery processes.
3.3.3 Energy recovery (incineration)
The unsorted residual waste is routed to a waste to energy plant. This is assumed to be a grate
combustor in which heat generated from waste is recovered through a Rankine steam cycle
for electrical and thermal energy production. In particular the Silla 2 waste to energy plant,
how modelled in Butera and Turconi (2010), is considered as the technological reference.
123
The flue gas cleaning system is composed, in sequence, by:

an electrostatic precipitator to remove fly ashes,

a dry reactor where acid gases are neutralized by means of sodium bicarbonate and
where activated carbon is employed to remove organic pollutants and metals,

a fabric filter to remove air pollution control residues originating from the previous
step and residual fly ashes,

a final stage of selective catalytic reduction (SCR) through urea and specific catalysts
for NOx control.
According to the same authors, the process originates three solid outputs:
-
Bottom ashes which are washed and sorted, obtaining an over-sift delivered to an inert
waste material landfill and an under-sift which is inactivated and reused as road
subgrade. Also iron and aluminium scraps are separated and sent to recycling.
-
Fly ashes that are inactivated through addition of lime and water and finally employed
as backfilling material in exhausted salt mines in Germany.
-
Air pollution control residues (APCR) which are recycled through the Neutrec process
to be partly employed in the manufacturing process of sodium carbonate, replacing
sodium chloride (NaCl). This process produce as output also a salt cake which is
disposed of into an hazardous material landfill.
Processes and emissions that have to be considered to define the impacts (generated and
avoided) associated with this treatment in a life cycle perspective will be now discussed.

Airborne emissions
To define these emissions, a given emission pattern is considered since it has been observed
that concentration values are mainly function of the adopted flue gas cleaning system rather
than of the waste composition during the incineration of municipal solid waste (Consonni et
al., 2005). In particular, stack concentrations data relative to the Silla 2 waste to energy plant,
showed in table 3.17, are considered (Butera and Turconi, 2010).
Emission factors of each pollutant (as kg/kgWW) are then obtained by multiplying these
concentrations by the specific flue gas volume that is calculated on the basis of the average
elemental composition of plastic, reported in table 3.16, and considering five main oxidation
reactions:
124
C  O 2  CO 2
S  O 2  SO 2
2 H  12 O 2  H 2O
N  1 O 2  NO
2
2 Cl  H 2 O  2 HCl  1 2 O 2
Being sulphur and nitrogen content of plastic equal to zero, the contribution of sulphur
dioxide (SO2) and nitrogen monoxide (NO) to the flue gas volume is null. A flue gas
production equal to 12.2 m3n
dry gas/kg WW
(13 m3 n
wet gas/kgWW)
with 11% oxygen content is
resulted. The respective emission factors are instead reported in the second column of table
3.17.
It is worth to notice that airborne emissions of nitrogen oxides are considered even if the
oxidation of nitrogen to nitrogen monoxide does not take place. In fact these pollutants can
also originate from the nitrogen contained in combustion air besides from the one contained in
waste.
On the contrary, SO2 emissions should not occur but they are anyway considered, according
to a conservative approach.
Carbon dioxide (CO2) emissions are finally calculated on the basis of the carbon content of
the incinerated waste fraction (in this case plastic).
Table 3.16: Average elemental composition considered for plastic (Rigamonti, 2007)
%W
C Cl H O N S Ashes Total
59 2.4 7.1 21.9 0 0 9.6
100
%WW
Ashes Moisture Volatiles Total
9
6
85
100
125
Table 3.17: Assumed pollutant stack concentrations and calculated emission factors for the WTE plant
Concentrations
@ 11% O2, dry gas Emission factors
mg/m3n
mg/kgWW
Particulate
0.09
1.1
TOC*
0.4
4.88
CO
5.8
70.8
HCl
1.9
23.2
SOX
0.4
4.88
NOX
39.6
483.6
NH3
0.71
8.67
N2O
0.96
11.7
HF
0.13
1.59
ng/kgWW
PCDD/F
0.0018
0.0220
g/kgWW
PAH
0.052
0.635
Sb
0.5
6.11
As
1.1
6.11
Cd+Tl
0.5
13.43
Cr
0.5
6.11
Co
0.5
6.11
Cu
2
6.11
Pb
0.6
7.33
Mn
0.5
7.33
Hg
0.6
24.42
Ni
0.5
6.11
Sn
0.5
6.11
V
0.65
7.94
mg/kgWW
Zn
0.0184
0.225
kg/kgWW
Fossil CO2
2.03
(*) Modelled as Non Methanic VOC in the LCA software
Pollutants

Reagent consumption for flue gas cleaning
Sodium bicarbonate requirement is defined on the basis of the stoichiometry of the
neutralization reactions that take place between this reagent and the amount of hydrochloric
acid (HCl) and of sulphur dioxide (SO2, absent in the case of plastic) contained in flue gas,
considering an excess of 25% with respect to the stoichiometric request and assuming a
complete neutralization of acid fractions.
Regarding activated carbon, its consumption is instead obtained assuming a dosage of 400
mg/mn3 dry gas, independently from the flue gas composition.
Finally, the request of urea can be calculated considering the stoichiometry of the reaction
between this reagent and nitrogen monoxide (NO) contained in flue gas, assuming a complete
126
conversion of NO and a stoichiometric excess pair to 2. Since plastic elementary composition
lacks nitrogen, a null consumption of ammonia is resulted, but airborne emissions of nitrogen
oxides are considered anyway as earlier specified. Consumptions resulted from these
calculations are reported in table 3.18.
Table 3.18: Reagents consumption for flue gas cleaning
Amount
(g/kgWW)
Sodium bicarbonate (NaHCO3)
66.7
Activated carbon
4.9
Urea CO(NH2)2
0
Reagent

Treatment of bottom ashes
Production of bottom ashes is assumed to be equal to the amount of ashes contained into the
specific incinerated waste fraction and considering an acquired moisture of 20% after their
putting out. In the case of plastic a specific production of 112.8 g/kgWW is resulted. During
their sorting, about 13% of over-sift (landfilled) and 87% of under-sift originate and therefore
a specific production of 14.7 g/kgWW and 98.1 g/kgWW occurs. These results are summarized
in table 3.22.
The energy requirement for sorting operation amount to 4 kWh/tbottom ashes which in this case is
equal to 4.5×10-4 kWh/kgWW (table 3.22).
The process of under-sift inactivation is carried out through addition of cement and iron
sulphate which consumptions, together with the energetic one, are reported in table 3.19.
Since the inactivated material will be then utilised as road subgrade, the avoided production
of gravel, which is the kind of material generally employed for this purpose, is also
considered as compensatory process. In particular an amount of inactivated material equal to
1030 kg/tundes-sift is calculated to be generated by the process, according to the added amount
of cement and iron sulphate. A corresponding amount of gravel is therefore considered to be
substituted. An amount of 101.1 g of road construction material per kgWW is produced through
this process in the case of plastic incineration (table 3.22).
127
Table 3.19: Materials and energy inputs and outputs to and from the under-sift inactivation process
Amount
Material/energy
(kg/tunder-sift)
Electricity (kWh/tunder-sift)
1
Cement
20
Iron sulphate (Fe2(SO4)3) – as 8% solution*
10
Gravel (avoided)
1030
(*) The consumption of 0.8 kg/tunder-sift of iron sulphate and
9.2 kg/tunder-sift of demineralised water is therefore considered
Iron and aluminium scraps recovery processes are not taken into account because of the lack
of this fractions into the treated waste.

Fly ashes inactivation
Fly ashes production is estimated by considering a concentration in raw gas equal to 3 gfly
3
ashes/mn wet gas,
resulting thus equal to 36.6 gfly ashes/kgww.
The inactivation process involves a consumption of lime and water in the amount reported in
table 3.20, implying therefore the production of 47.4 g/kgww of inactivated fly ashes employed
as backfilling material in exhausted salt mines in Germany (table 3.22).
Table 3.20: Materials consumptions for fly ashes inactivation
Amount
Material
(kg/tfly ashes)
Water*
225
Lime (CaOH2)
70
(*) Modelled as natural resource without
assigning any production burden

Air pollution control residues treatment
Air pollution control residues (APCR) are represented by sodium chloride, sodium sulphate,
not reacted sodium bicarbonate as well as by activated carbon. The first three can be
calculated considering reactions stoichiometry, resulting equal to 50.5 gAPCR/kgWW that
together with the employed activated carbon (4.9 g/kgWW) constitutes a whole amount of 55.4
gAPCR/kgWW.
Through the Neutrec process the air pollution control residues are involved in a series of
treatments that bring to obtain a brine (salt solution) directly employable in the manufacturing
cycle of sodium carbonate in place of mineral NaCl, and a salt cake which is instead disposed
off within an hazardous material landfill. This last is generated with a water content of about
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45% in an amount equal to 145.8 kg/tAPCR, which corresponds therefore to a residual dry
product of 145.8×(1-0.45) = 80.2 kg
dry cake/t APCR.
This means that the amount of APCR (as
salts) remained in the brine can be roughly estimated as (1000-80.2) = 919.8 kgsalts/tAPCR.
Considering after that 2860 kgH2O/tAPCR are employed for the initial APCR dissolution, of
which 0.45×145.8 = 65.6 kgH2O/tAPCR represent the water content of the cake, this means that
the amount of brine obtained from the process is equal to 919.8 kgsalts/tAPCR+(286065.6)kgH2O/tAPCR=3714.2 kgbrine/tAPCR. Considering finally that the brine density is of about
1250 kg/m3 and has an equivalent NaCl concentration of about 250 kgNaCl/litre, it is possible
to estimate the amount of NaCl that will be substituted as:
M NaCl_subst ituted 
3714.2 kg brine /t APCR
 0.250 kg NaCl /litre brine  742.8 kg NaCl /t APCR
1.25 kg brine /litre brine
Table 3.21 summarises the materials inputs and outputs of the process, how calculated above,
as well as the energy consumptions involved.
Table 3.21: Materials and energy inputs and outputs to and from the Neutrec APCR recovery process
Amount
(kg/tAPCR)
Electricity (kWh/tAPCR)
30
Water*
2860
Dry residues to landfill (salt cake)
80.2
Sodium chloride (NaCl) - avoided
742.8
(*) Modelled as natural resource without assigning
any production burden
Material/energy

Energy production
The amounts of electrical and thermal energy produced by the process, are calculated
considering respectively a 24.2% and a 5.5% conversion efficiency and a plastic lower
heating value (LHV) of 26176 MJ/kgww. A production of 1.76 kWh/kgww and of 0.004
kWh/kgww of electric and thermal energy are therefore resulted (table 3.22). The former is
assumed to replace the production of an equivalent amount of electricity from the Italian
country mix while the latter of heat generated from domestic methane boilers placed at the
service of a district heating system, for an amount reduced of 20% to account for distribution
and exchange losses. The avoided burdens associated with these two processes are hence
credited to the system.
129
Table 3.22 summarises the energy and material outputs from the incineration process
described up to now, while table 3.23 shows the other process specific energy and material
consumptions assigned to the plant, always as reported by Butera and Turconi (2010).
Table 3.22: Summary of energy and material outputs from the incineration process
Amount
(g/kgWW)
Material/energy
Bottom ashes
of which:
112.8
Over-sift to inert material landfill
Under-sift to inactivation
Inactivated under-sift
Fly ashes
14.7
98.1
101.1
36.6
Inactivated fly ashes to salt mines
47.4
Air pollution control residues
55.4
Energy: Electricity for bottom ashes sorting (kWh/kgWW) 4.5×10-4
Electricity production (avoided) (kWh/kgWW)
1.76
Heat production (avoided) (kWh/kgWW) 0.0032
(*) A plastic lower heating value of 26,176 kJ/kgWW is considered
Table 3.23: Summary of process specific energy and material inputs to the incineration treatment
Material/energy input
Electricity (kWh/kgWW)
Methane (MJ/kgWW)
Diesel
Hydrogen chloride (HCl)
Sodium hydroxide (NaOH)
Sodium hypochlorite (NaClO)
Amount
(g/kgWW)
6.22×10-3
5.68 ×10-2
8.63×10-3
0.229
0.234
0.19
Regarding the modelling in SimaPro, the module Plastic incineration is built up in order to
account for the environmental burdens associated with the incineration of 1 kg of plastic
waste. It encompasses all direct emissions to air as well as all the processes associated with
reagents manufacturing, bottom and fly ashes inactivation, treatment of air pollution control
residues, the avoided production of electricity and heat and the process specific raw material
consumptions described above.
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3.4 LCA modelling of scenarios
3.4.1 WasteMAP LCA model
As described in paragraph 2.3.1.1 the WasteMAP LCA is a conceptual model in which waste
prevention activities involving dematerialization are considered as functionally equivalent to
traditional waste management treatments. This implies that the amount of waste managed
through treatments and waste prevention activities remains constant in all the
systems/scenarios to be compared. Waste prevention activities that involve reduced
consumption cannot be seen instead as functionally equivalent to the other waste management
options since a waste management option cannot affect the magnitude of the service supplied
to the population by waste generating product systems. Functional equivalence of prevention
activities and therefore of scenarios is assured by means of introducing a secondary functional
unit that guarantees that the magnitude of service supplied to the population remains the same
within all the scenarios to be compared.
This model appear to be relatively complex, probably due to the fact that the author desires to
propose a rigorous methodology strongly consistent with the ISO standards. In this analysis
we have tried to follow as much as possible the models in the way it is originally described by
the author, even if some little adjustments are made.
Functional unit
The model adopts a primary functional unit (PFU) that is the same for all the compared
scenarios, which ensures that a fixed amount of (potentially generated) waste is managed
under each of them and which leads the overall analysis. This is originally defined as:
“the amount of material addressed by the municipal solid waste management system on an
annual basis”.
As already reported in paragraph 2.3.1.1 a more clear reformulation, here associated with the
specific case under investigation, could be:
“the management of the annual amount of (plastic) waste potentially produced by one
inhabitant of the Lombardia Region”,
which will be therefore considered for the present analysis.
We also remember that the primary functional unit is further subdivided into an upstream
primary functional unit (UPFU) and a downstream primary functional unit (DPFU), with the
131
former defined as “the net amount of material left out of the municipal solid waste treatment
system due to waste prevention activities”, while the latter “tracks the amount of waste that
still have to be collected and treated under each scenario”. This subdivision is necessary since
the WasteMAP LCA is actually the composition of different life cycle assessments as will
emerge more in detail from the following practical application.
Baseline scenario
In this scenario no waste prevention activities are implemented.
The respective environmental burdens and impacts have to be determined by means of a
traditional waste management oriented LCA of a reference waste management systems (REF
WMS) which deals with the whole amount of potentially generated waste.
The functional unit to be used in the analysis is the primary functional unit, that in this case is
identical (in numerical terms) to the downstream primary functional unit, which could be
defined as:
“the collection and treatment of the annual amount of (plastic) waste produced by one
inhabitant of the Lombardia Region”, that in this baseline scenario is equal to 81.7
kg/inhabitant/year (table 3.24).
This issue was clarified thanks to a personal communication with the author (Cleary, 2010a)
since it does not explicitly emerge from the original paper.
The amount of each waste fraction entering the management system in this baseline scenario
is that reported in table 3.11, here presented again in table 3.24 for the sake of readability.
Table 3.24: Amount of each waste fraction entering the waste management system in the baseline scenario
PET bottles
3.42
PET CFL*
35.2
HDPE CFL*
12.5
POLYOLEFINES mix
30.6
Total
81.7
(*) CFL=Containers for liquid
According to the selection and recovery efficiencies defined in paragraphs 3.3.1 and 3.3.2, it
is possible to calculate through mass balances the main waste flows within the management
system, which are schematically represented in figure 3.1, that also defines the ideal system
boundaries adopted since no upstream life cycle processes will be included in this scenario.
132
Separately
collected
material
Input
waste
=
81.7 kg
Recovered
material
=80%
PET bottles
3.42 kg
=77%
2.63 kg
PET CFL1
35.2 kg
=77%
27.1 kg
HDPE CFL1
12.5 kg
=77%
9.61 kg
POF2 mix
30.6 kg
=33%
10.1 kg
2.11 kg
=80%
21.7 kg
=90%
8.65 kg
=60%
6.07 kg
Total=49.5
32.3 kg
(2) POF=Polyolefines
Total=38.5
Scraps
11 kg
Incineration
43.3 kg
Figure 3.1: Mass flows within the waste management system of the baseline scenario modelled through the
WasteMAP LCA model and respective ideal boundaries
The downstream processes with the respective burdens that have to be included in the system
in a life cycle perspective are therefore the following:

selection of separately collected plastic (49.5 kg);

recovery of selected plastic:

PET bottles (2.63 kg) ;

PET containers (27.1 kg);

HDPE containers (9.61 kg);

POF mix (10.1 kg);

incineration of plastic in the residual waste (32.3 kg) and

incineration of recovery scraps (11 kg).
The whole scenario is implemented in SimaPro by creating the new module Baseline scenario
which account for all these processes by recalling the modules described in paragraphs 3.3.2
and 3.3.3, except for scraps incineration that is already included in the PET recovery module.
Target product system
This model foresees that the upstream life cycle processes affected by waste prevention are
modelled as parts of separated product systems: the Target product system (TPS) and the
133
Alternative product system (APS). The service provided by the former is the one whose
consumption is going to be reduced in favour of the service provided by the latter, which is a
less waste generating product system. In the present case, the target product system is
associated with bottled water delivering while the alternative product system is associated
with tap water delivering.
The functional equivalence between baseline and prevention scenario, as well as between
waste prevention and the other waste management options, is assured only if the amount of
service provided to the citizens by these two product systems in the respective scenarios is the
same.
This equivalent level of supplied service is assured by the introduction of a secondary
functional unit which has to be considered when carrying out the analysis of the two product
system.
In our specific case the secondary functional unit can be assumed:
“the delivering of 152.1 litres of drinking quality water to one inhabitant of the Lombardia
Region for 1 year”.
The overall annual specific consumption of 152.1 litres/inhabitant/year previously estimated
(table 3.8) is considered because the whole amount of PET bottles will be assumed for
simplicity to be prevented in the waste prevention scenario as will be detailed in the
respective paragraph Waste prevention scenario.
The reference flow is therefore assumed to be “152.1 litres of drinking quality water delivered
to an inhabitant of the Lombardia Region during a year”. This will be the same for each one
of the two product systems considered.
The Target product system in our case is represented by all the upstream life cycle processes
involved in supplying bottled water to citizens, while the Alternative product system by all
those processes involved in delivering them purified tap water.
With regard to the target product system in this simplified analysis we have however only
considered the processes involved in bottles manufacturing whose last step is generally
carried out nearby bottling facilities and consists in the stretch blow moulding of heated PET
preforms. These can be substantially considered the compact form of bottles and are similar to
test tubes composed by a tubular body and a threaded neck which are in turn manufactured
through the injection moulding of melted bottle grade PET granules. Further details
concerning these processes will be given in paragraph 4.5.2.
134
From a waste manager point of view, considering the sole manufacturing processes of the
products that would potentially become waste could be enough to have some first indications
concerning the potential environmental benefits that a waste prevention activity is expected to
involve. Nonetheless, from a life cycle perspective it would be more proper to include in the
analysis all the relevant processes involved in bottled water delivering and this will be done in
the detailed analysis described in chapter 4. The inclusion of these processes within the
system is however expected to amplify the benefits potentially associated with waste
prevention, while their disregarding, as in the present case, can be done according to a
conservative approach.
Inventory data utilised to model bottle grade PET granules production are those provided by
the module Polyethylene terephtalate, granulate, bottle grade, at plant/RER available in the
Ecoinvent database. The module Stretch blow moulding/RER, always from Ecoinvent, which
models the manufacturing of bottles from PET granules through the two step process of
preforms injection and direct blowing is instead employed to model the real process that
generally takes place in two separate stages.
As specified in the database, a 97.8% conversion efficiency of PET granules into bottles has
been considered because of process losses. The new module PET bottles production is thus
built up in order to account for the burdens associated with the production of 1 kg of PET
bottles starting from 1.0225 kg of virgin PET granules, by recalling the two modules specified
above.
This module, which actually represents the only upstream component of the target product
system, is in turn employed to create the module UpTPS bottled water to account for the
production of 3.42 kg of PET bottles which are required to deliver 152.1 litres of bottled
water to the citizens.
Alternative product system
The upstream life cycle processes of the alternative product system are instead those involved
in delivering to citizens an amount of tap water equivalent to the one that would have been
supplied by the bottled water system. In order to model the burdens associated with tap water
delivering, the Ecoinvent module Tap water, at user/RER which refers to average data for the
European context, is employed here as a first approximation. In the detailed analysis of
chapter 4, two real Italian case studies will be however examined in order to give more
135
reliability to the assessment. The possibility of domestic purification of water is not
considered as well, even if this will be done in the detailed analysis.
The module UpAPS tap water is finally created by recalling the above mentioned module to
account for the delivering of 152.1 litres of drinking quality tap water to the citizens.
Waste prevention scenario
This scenario, as well as all the preventive scenarios that will be investigated with the other
models, considers, for simplicity, that the whole amount of PET bottles present in the waste
stream (3.42 kg/inhabitant/year) is prevented. In this way the amount of each waste fraction
entering the waste management system is the same of the baseline scenario except for the
amount of prevented PET bottles, as showed in table 3.25. In particular an amount of 78.3
kg/inhabitant/year still have to be managed.
Table 3.25: Amount of each waste fraction entering the waste management system in the waste prevention
scenario
PET bottles
0
PET CFL*
35.2
HDPE CFL*
12.5
POLYOLEFINES mix
30.6
Total
78.3
(*) CFL=Containers for liquid
According to this model, in order to calculate the environmental burdens and associated
impacts of the waste prevention scenario, it is before necessary to define those of a waste
management system that treats the residual amount of waste that still have to be managed
after the implementation of waste prevention activities. This system is termed DOWN WMS,
slightly modifying the original terminology of the author.
This means to carry out a further waste management oriented LCA to obtain the
environmental impacts of such a waste management system. In particular it has to be
performed assuming as functional unit the downstream primary functional unit (DPFU) that,
as done for the baseline scenario, is considered to be:
“the collection and treatment of the annual amount of (plastic) waste produced by one
inhabitant of the Lombardia Region”, that in this preventive scenario is equal to 78.3
kg/inhabitant/year (table 3.25).
136
Figure 3.2 provides a representation of the main waste flows characterizing the DOWN waste
management system, always calculated on the basis of the efficiencies reported in paragraphs
3.3.1 and 3.3.2. It also defines the ideal system boundaries adopted since no upstream life
cycle processes will be included in this scenario.
Separately
collected
material
Input
waste
=
78.3 kg
Recovered
material
=80%
PET CFL1
35.2 kg
=77%
27.1 kg
HDPE CFL1
12.5 kg
=77%
9.61 kg
POF2 mix
30.6 kg
=33%
10.1 kg
21.7 kg
=90%
8.65 kg
=60%
Total=46.8
31.5 kg
6.07 kg
Total=36.4
Scraps
10.4 kg
Incineration
41.9 kg
Figure 3.2: Mass flows within the DOWN waste management system belonging to the waste prevention scenario
modelled through the WasteMAP LCA model and respective ideal boundaries
The downstream life cycle processes that have to be considered in the analysis are therefore

 recovery of selected plastic:



POF mix (10.1 kg);


incineration of recovery scraps (10.4 kg).
The new module DOWN WMS is created in SimaPro to account for all these processes by
recalling the modules described in paragraphs 3.3.2 and 3.3.3, except for scraps incineration
that is already included in the PET recovery module.
137
As described in paragraph 2.3.1.1 the actual burdens/impacts of the waste prevention scenario
(WPS) can be calculated through the following equation, in the case in which only one
prevention activity is considered o be undertaken:
WPS  DOWN WMS  UpTPS  UpAPS
(3.1)
where:
WPS = Generic environmental burden/impact of the waste prevention scenario;
DOWN WMS = Generic environmental burden/impact of the DOWN waste management
system;
UpTPS = Generic environmental burden/impact of the upstream life cycle of the target
product system;
UpAPS= Generic environmental burden/impact of the upstream life cycle of the alternative
product system.
By looking at equation 3.1 it is clear how, in order to calculate the burdens/impacts of a waste
prevention scenario, three distinct life cycle analyses have to be performed.
As specified in paragraph 2.3.1.1, the author suggests two possible procedures to calculate the
environmental impacts of a waste prevention scenario. The first for the cases in which it is
possible to assume that the implementation of waste prevention activities does not involve
any effects on the treatments of the waste remaining in the system, the second for those cases
in which this assumption is instead not valid.
In this analysis the second procedure has been adopted since it could be applied to both the
typologies of cases and is therefore of general validity. Moreover, the number of calculations
required appear to be the same for both methods and it seems that no specific advantages are
associated with one method rather than with the other.
Results
As anticipated, only the impact category Global Warming (GW) calculated trough the
characterization method CML 2001 baseline is considered as a term of comparison for the
models. For further details concerning the modality of calculation of this indicator, see
paragraph 4.4.
Despite the simplified nature of this analysis, some preliminary remarks concerning the
assessed scenarios will be however given during the presentation of the results. We also
138
underline here that the overall results interpretation has to be made in differential terms,
evaluating the net difference of the impact indicator between the baseline and the waste
prevention scenario. The present analysis indeed is not an absolute accounting of the impact
associated with a certain product system (or rather with a service system in our case) but a
comparison between two different ways to carry out this service.
The values of the impact indicator associated with each sub-system that contributes to define
the overall impact of the waste prevention scenario (WPS) are reported in table 3.26 together
with the result from equation 1 that just defines this overall impact.
In table 3.27 are instead reported in comparison, the impact indicators calculated for both the
baseline and the waste prevention scenario (WPS) as well as their difference. Figures 3.3 and
3.4 graphically represent the results from the previous tables while in table 3.28 are finally
specified the contributions of the main processes to the impact of each sub-system and of the
baseline scenario.
Table 3.26: Global warming impact indicator calculated through the WasteMAP LCA model for each subsystem that contribute to define the overall impact of the waste prevention scenario and for the waste prevention
scenario itself
Global warming (GW) - kg CO2 eq./F.U.
Sub-system
Indicator
0.7
DOWN WMS
15.5
UpTPS
0.05
UpAPS
-14.8
Waste prevention scenario (WPS)
Table 3.27: Global warming indicator calculated through the Waste MAP LCA model for each analysed
scenario and relative difference
Scenario
Indicator
Baseline scenario (BLS) = REF WMS
-1.5
-14.8
-13.2
 (WPS-BLS)
139
Table 3.28: Contribution of main processes to the global warming impact indicator calculated through the
WasteMAP LCA model for each sub-system and for the baseline scenario
Scenario
Bseline scenario (BLS) = REF WMS
DOWN WMS
UpTPS
UpAPS
 (DOWN WMS-BLS)
Total
Plastic
recycling
Plastic
incineration
-1.5
0.7
15.5
0.05
2.2
-37.3
-34.3
3.1
35.8
34.9
-0.9
Tap
PET bottles
water, at
production
user
15.5
0.05
-
Global warming
kg CO2 eq/F.U.
Baseline scenario
(BLS)
0
Waste prevention
scenario (WPS)
DELTA (WPS-BLS)
-14.8
-13.2
-1.5
-5
-10
-15
Figure 3.3: Global warming impact indicator calculated through the WasteMAP LCA model for each analysed
Global warming
Baseline scenario (BLS)
kg CO2eq/F.U.
5
(WPS)
0.7
0
-5
UpAPS
-1.5
-10
-15
-15.5
-UpTPS
DOWN WMS
-20
Figure 3.4: Sub-systems contribution to the global warming impact indicator calculated through the WasteMAP
LCA model for each analysed scenario
As can be noticed, the value of the impact indicator obtained for the waste prevention
scenario (-14.8 kg CO2 eq.) is clearly lower with respect to the one obtained for the baseline
scenario (-1.5 kg CO2 eq.), meaning that the implementation of this prevention activity is
140
potentially associated with an environmental benefit because involves a reduction of -13.2 kg
CO2 eq. from the baseline scenario.
More in depth, looking at table 3.28 and figure 3.4, it can be observed that the impact of the
traditional treatments of the waste management system in which waste prevention is
implemented (DOWN WMS) equal to 0.7 kg CO2 eq., is higher than the one of the baseline
scenario (-1.5 kg CO2 eq.). This because, in addition to a decrease of the loads associated with
the incineration process (-0.9 kg CO2 eq.), also an higher decrease of the savings associated
with plastic recycling takes place when waste prevention is implemented (3.1 kg CO2 eq.). A
great fraction of bottles (77%) would indeed have routed to recycling in baseline scenario,
while only a small percentage (33%) of them would have sent to incineration, which in the
case of plastic does not imply environmental benefit as indeed happens for recycling. As
consequence if no upstream processes was considered, an overall impact increase would
characterize the implementation of this prevention activity.
When the impacts associated with the target product system, and therefore to bottles
production, are subtracted from the downstream waste management system (DOWN WMS)
(15.5 kg CO2eq.), an overall reduction of the impact of the waste prevention scenario with
respect to the baseline can be observed, because the additional loads associated with purified
tap water supplying, represented by the alternative product system, are of negligible entity
(0.05 kg CO2 eq.). Due to the simplified nature of the analysis these indications have to be
taken with caution, especially according to the incompleteness of the life cycle considered to
characterize tap water. However these results represent a good reason to carry out a more
thorough analysis, as will be done in chapter 4.
3.4.2 Integrated Scenarios Waste Prevention Model (ISWPM)
Similarly to the previous model also in the present one waste prevention is considered as a
part of the service provided by the waste management system itself.
According to this principle the functional unit of this model is assumed to be:
“the integrated management of the annual amount of (plastic) waste potentially produced by
one inhabitant of the Lombardia Region, in which a prevention activity is undertaken”.
In this way the amount of potentially generated waste managed by conventional treatments
and prevention is the same within all compared scenarios and equal to 81.7 kg.
141
Baseline scenario
This scenario can be modelled exactly as the baseline scenario of the WasteMAP LCA model
in which all the waste fractions of table 3.24 are managed through conventional treatments
since no waste prevention activities are implemented in this scenario. The amount of waste
entering the traditional waste treatment system is therefore the same of the amount of waste
that could potentially be produced, as schematically depicted figure 3.5 along with the major
flows occurring in the system itself, which are analogous to those represented in figure 3.1 for
the WasteMAP LCA model.
Separately
collected
material
Potentially
produced
waste
=
Input
waste
=
81.7 kg
Recovered
material
=80%
PET bottles
3.42 kg
=77%
2.63 kg
PET CFL1
35.2 kg
=77%
27.1 kg
HDPE CFL1
12.5 kg
=77%
9.61 kg
POF2 mix
30.6 kg
=33%
10.1 kg
2.11 kg
=80%
21.7 kg
=90%
8.65 kg
=60%
6.07 kg
Total=49.5
32.3 kg
Total=38.5
Scraps
11 kg
Incineration
43.3 kg
ISWP model and respective ideal boundaries
The downstream processes with the respective burdens included in the system are therefore
the following:






POF mix (10.1 kg);
142


The whole scenario is implemented in SimaPro with the module Baseline scenario which
account for all these processes by recalling the respective modules described in paragraphs
3.3.2 and 3.3.3, except for scraps incineration that is already included in the PET recovery
module.
The peculiarity of this scenario is that a specific amount of potentially produced waste (3.42
kg of PET bottles) is managed through waste prevention, while the other fractions are still
managed as in the baseline scenario. The waste entering the conventional treatment system
(input waste) is therefore reduced to 78.3 kg (figure 3.6).
Prevention has to be seen as a specific waste management option/process that avoids the
supplying of 152.1 litres of bottled water to the citizens, responsible of the generation of 3.42
kg of PET bottles, and in the same time involves the additional need of supplying 152.1 litres
of purified tap water to the citizens. The avoided burdens associated with the avoided
supplying of bottled water are therefore credited to the system while the burdens associated
with the supplying of tap water are charged to the system. The system boundaries of the
traditional waste management system are therefore expanded to include these upstream life
cycle processes as showed in figure 3.6, together with the main waste flows occurring in the
system itself.
143
Separately
collected
material
Prevention
PET bottles Potentially
3.42 kg
produced
Bottled water
avoided
production
152.1 litres
(3.4 kg bottles)
Tap water
supply
152.1 litres
waste
PET CFL1
=
35.2 kg
81.7 kg
>
HDPE CFL1
Input waste
12.5 kg
=
78.3 kg
POF2 mix
30.6 kg
Recovered
material
=80%
=77%
27.1 kg
=77%
9.61 kg
=33%
10.1 kg
21.7 kg
=90%
8.65 kg
=60%
6.07 kg
Total=36.4
Total=46.8
31.5 kg
Scraps
10.4 kg
Incineration
41.9 kg
Figure 3.6: Mass flows within the waste management system of the waste prevention scenario modelled through
the ISWP model and respective ideal boundaries
From a practical point of view, the module Prevention PET bottles is built up to take into
account the burdens associated with the avoided production of 3.42 kg of PET bottles (PET
bottles production) and with the additional need to deliver 152.1 litres of purified tap water to
citizen (Tap water, at user/RER).
In addition to this process, also those required for the treatment of not prevented fractions still
have to be considered. In particular they are:




POF mix (10.1 kg);


The module Waste prevention scenario, built up in the software, now depicts the fact 3.42 kg
of PET bottles are managed through prevention (Prevention PET bottles) while the remaining
fractions through the conventional treatments above indicated, by recalling the respective
modules described in paragraphs 3.3.2 and 3.3.3, except for scraps incineration that is already
considered in the PET recovery module.
144
Results
The values of the global warming impact indicator calculated for both baseline and waste
prevention scenarios as well as its difference between them are reported in table 3.29, together
with the contribution of the main involved processes to its definition. These results are also
graphically illustrated in figure 3.7 and 3.8 respectively.
Table 3.29: Global warming impact indicator calculated through the ISWP model for each analysed scenario
and contribution of the main processes to its definition
Scenario
Total Plastic recycling Plastic incineration Prevention PET bottles
-1.5
-37.3
35.8
Waste prevention scenario (WPS) -14.8
-34.3
34.9
-15.4
-13.2
3.1
-0.9
-15.4
 (WPS-BLS)
Global warming
kg CO2 eq/F.U.
Baseline scenario
0
Waste prevention
scenario
DELTA (WPS-BLS)
-14.8
-13.2
-1.5
-5
-10
-15
Figure 3.7: Global warming impact indicator calculated through the ISWP model for each analysed scenario
and relative difference
Global warming
kg CO2 eq/F.U.
Baseline scenario
50
40
30
20
10
0
-10
-20
-30
-40
-50
Waste prevention
scenario
35.8
34.9
-37.3
-34.3
DELTA (WPS-BLS)
3.1
-15.4
Prevention
PET bottles
Plastic
incineration
Plastic
recycling
-15.4
Figure 3.8: Main processes contribution to the global warming impact indicator calculated through the ISWP
model for each analysed scenario
145
As it can be observed either the absolute value of the impact indicator obtained for each
scenarios or its difference between them are the same that were obtained with the WasteMAP
LCA model.
This could be explained considering that even if the theoretical assumptions at the basis of the
models are in someway different, both are based on the same principle for the calculation of
burdens and impacts associated with the waste prevention scenario which is based on the
concept of avoided and additional impacts. The only difference, which is purely conceptual,
consists indeed in the fact that while in the WasteMAP LCA model they are manually
subtracted or added to the traditional waste management system, in this ISWP model they are
automatically credited as savings or charged to the system itself.
More in detail, as already emerged from the analysis of the results of the WasteMAP LCA
model, also in this case the effect of waste prevention is a potential increase of the impact
associated with the traditional waste management system treatments due to a small decrease
of the loads of the incineration process (-0.9 kg CO2 eq.) and to an higher decrease of the
savings of the recycling process (+3.1 kg CO2 eq.).
Actually into the waste prevention scenario the fact that part of the waste is managed through
prevention is accounted for and 15.4 kg CO2 eq. are credit to the system as saved. This once
more means that the avoided production of PET bottles masks the impact associated with
purified tap water supplying.
3.4.3 Separate Scenarios Waste Prevention Model (SSWPM)
According to this last proposed model, the functional unit assumed for the analysis is:
“the management of the annual amount of (plastic) waste produced by one inhabitant of the
Lombardia Region”.
This amount is supposed to change as a consequence of the implementation of waste
prevention activities.
In this way all scenarios are subjected to the same functional unit and their comparison is thus
allowed. The only difference among scenarios is the reference flow that is represented by the
actual amount of waste to be managed.
Doing so, since different amounts of waste enter the waste management system in each
scenario, the zero burdens assumption is, in general, no longer valid. In principle the burdens
associated with all the life cycle processes occurring upstream waste collection should be
146
considered. Actually, it could be done only for those processes which differ between the
scenarios for their typology or magnitude, as consequence of waste prevention activities. The
upstream life cycle processes that should be included in the specific case under investigation
are those associated with PET bottled water delivering for the baseline scenario, and those
associated with tap water delivering for waste prevention scenario.
Baseline scenario
The amount of each waste fraction entering the waste management system are always those
which characterize baseline scenarios of the two previous models and reported in table 3.11 or
3.24. In particular the total amount of waste to be managed is equal to 81.7 kg/inhabitant/year
that is therefore the reference flow for this analysis.
Moreover, since the considered waste prevention activity has PET water bottles as its target
flow, all the upstream life cycle processes involved in the delivering of 152.1 litres of bottled
water should be taken into account and the system boundaries of consequence expanded for
their inclusion. This because the magnitude of these processes is going to change from
baseline to waste prevention scenario.
On the basis of this consideration and according to the efficiencies reported in paragraphs
3.3.1 and 3.3.2, figure 3.9 shows the main waste flows characterizing the waste management
system indicating also which other upstream life cycle processes are included in the system
boundaries, giving therefore their ideal definition.
147
Separately
collected
material
Bottled water
supply
152.1 litres
(3.4 kg PET
bottles)
=80%
PET bottles
3.42 kg
=77%
2.63 kg
PET CFL1
35.2 kg
=77%
27.1 kg
=77%
9.61 kg
=33%
10.1 kg
Input
waste
81.7 kg HDPE CFL1
12.5 kg
POF2 mix
30.6 kg
Recovered
material
2.11 kg
=80%
21.7 kg
=90%
8.65 kg
=60%
6.07 kg
Total=49.5
Total=38.5
Scraps
11 kg
32.3 kg
Incineration
43.3 kg
SSWP model and respective ideal boundaries
As consequence the downstream processes with the respective burdens that have to be
considered are:


-
-
-
-
POF mix (10.1 kg);


The whole scenario is therefore implemented in SimaPro with the module Baseline scenario
which account for the downstream processes described above by recalling the respective
modules described in paragraphs 3.3.2 and 3.3.3 as well as the manufacturing of 3.42 kg of
PET bottles (PET bottles production), required for the delivering of 152.1 litres of bottled
water to the citizens. Scraps incineration is instead not included since it is already considered
in the PET recovery module.
148
From a theoretical point of view this is how to consider that in order to be able to manage
3.42 kg of wasted PET bottles, 152.1 litres of bottled water have first to be delivered,
involving the respective burdens.
The amount of each waste fraction entering the waste management system is the same of the
baseline scenario except for the amount of prevented PET bottles (3.42 kg). The reference
flow is therefore the management of 78.3 kg/inhabitant/year of plastic waste.
The downstream processes that have to be considered in the waste management system are
therefore the same as for the baseline scenario except for those involving PET bottles. In
particular they are:

-
-
-
POF mix (10.1 kg);


Clearly the upstream life cycle processes associated with bottled water supplying are no more
considered since they are subjected to a null mass flow because of prevention activity while it
is now necessary to account for those processes associated with the delivering of a volume of
tap water equal to the one previously supplied by prevented water bottles in the baseline
scenario (152.1 litres/inhabitant/year). This because, once more, the magnitude of these
processes changes from baseline to waste prevention scenario. From a theoretical point of
view this is how to consider that in order to manage a lower amount of waste these additional
processes with the respective burdens, are required.
On the basis of these considerations figure 3.10 represents the waste flows occurring in the
waste management system and the processes included in the system boundaries.
149
Separately
collected
material
Tap water
supply
152.1 litres
PET CFL1
35.2 kg
Input HDPE CFL1
waste
12.5 kg
78.3 kg
POF2 mix
30.6 kg
Recovered
material
=80%
=77%
27.1 kg
=77%
9.61 kg
=33%
10.1 kg
21.7 kg
=90%
8.65 kg
=60%
6.07 kg
Total=36.4
Total=46.8
Scraps
10.4 kg
31.5 kg
Incineration
41.9 kg
Figure 3.10: Mass flows within the waste management system of the waste prevention scenario modelled
through the SSWP model and respective ideal system boundaries
The whole scenario is implemented in SimaPro with the module Waste prevention scenario
which include all the downstream processes described above by recalling the respective
modules described in paragraphs 3.3.2 and 3.3.3 as well as the one associated with the
delivering of 152.1 litres of purified tap water (Tap water, at user/RER). Scraps incineration
is instead not included since it is already considered in the PET recovery module.
Results
The global warming impact indicator calculated for the analysed scenarios both in absolute
and in differential terms is reported in table 3.32 together with the contribution given by the
main processes to its definition. Figures 3.11 and 3.12 also graphically depict these results.
Table 3.30: Global warming impact indicator calculated through the SSWP model for each analysed scenario
Plastic
Plastic
Scenario
Total
recycling incineration
14.0
-37.3
35.8
0.7
-34.3
34.9
-13.2
3.1
-0.9
 (WPS-BLS)
PET bottles Tap water,
production
at user
15.5
0.05
-15.5
0.05
150
Global warming
kg CO2 eq/F.U.
Baseline scenario
Waste prevention
scenario
DELTA (WPS-BLS)
15
14.0
10
5
0.7
0
-5
-10
-13.2
-15
Figure 3.11: Global warming impact indicator calculated through the SSWP model for each analysed scenario
and relative difference
Global warming
kg CO2 eq/F.U.
Baseline scenario
60
50
40
30
20
10
0
-10
-20
-30
-40
Waste prevention
scenario
DELTA (WPS-BLS)
15.5
35.8
34.9
3.1
-15.5
-37.3
-34.3
Tap w ater, at
user
PET bottles
production
Plastic
incineration
Plastic
recycling
Figure 3.12: Main processes contribution to the global warming impact indicator calculated through the SSWP
model for each analysed scenario
As expected the values of the impact indicator obtained for the two scenarios is different from
those obtained with both the previous LCA models (WasteMAP LCA and ISWP model). The
present model indeed, though always applying system expansion, does not foresee to assign
any credit to the preventive scenario but rather to account for the processes that actually are
subject to change from one system to the other.
In particular the baseline scenario is characterized by an higher value of the impact indicator
with respect to the two previous models (14 kg CO2 eq. against -1.5 kg CO2 eq.) because it
also brings the burdens associated with PET bottles production that was not included in
baseline scenarios by the other models. The same happens for the preventive scenario (0.7 kg
CO2 eq. against -14.8 kg CO2 eq.) which is not credited of the savings associated with the
avoided production of PET bottles, as were instead made by the previous models. Despite of
151
this, the model give the same result of the previous one in terms of impact difference between
the two scenarios (-13.2 kg CO2 eq.) meaning that this potential impact reduction is expected
to be achieved by the introduction of the prevention activity.
Moreover as for the previous model a decrease of the loads associated with the incineration
process of 0.9 kg CO2 eq. together with a decrease of the savings associated with plastic
recycling of 3.1 kg CO2 eq. leads to an overall potential increase of the impact of
conventional waste management system components if no upstream processes were taken into
account. Actually the waste prevention scenario lacks the positive contribution of bottles
production that instead is present in baseline scenario (15.5 kg CO2 eq.) while the additional
need of supplying an amount of tap water equivalent to that consumed in baseline scenario
from bottled water does not imply any meaningful impact increase to be assigned to it (only
0.05 kg CO2 eq.). All this leads therefore to the overall reduction from baseline to waste
prevention scenario of -13.2 kg CO2 eq. above indicated.
3.4.4 Comparative considerations
The most important features of the application of three investigated models to the specific
case study analysed in this chapter are summarized in table 3.31. Some considerations at
conceptual level, already specified in table 2.1 are also reported for reason of clarity.
152
Table 3.31: Major features of the LCA models discussed in this chapter
FEATURES\
MODELS
WatseMAP LCA
(Cleary, 2010b)
ISWPM
SSWPM
(Primary)
functional
unit
annual amount of (plastic)
waste potentially produced
by one inhabitant of the
Lombardia Region)”
(leads the overall analysisthe amount of waste to be
scenarios)
“the integrated management
of the annual amount of
(plastic )waste potentially
produced by one inhabitant
of the Lombardia Region, in
which a waste prevention
activity is undertaken”.
(the amount of waste to be
scenarios)
annual amount of (plastic)
waste produced by one
inhabitant of the Lombardia
Region)”
(the amount is subject to
change between scenarios)
-
-
-
-
part of the service provided
by the WMS1 – is an actual
component of the WMS -
no need to consider waste
prevention as a component
of the WMS
the burdens of TPSs2 are
assigned to the BL4 scenario
and those of APSs2 are
assigned to the WP3 scenario
(are assigned to the system
in which they actually take
place)
Downstream
primary
functional
unit
Secondary
functional
unit
(if required)
Position
of waste
prevention
Approach to
traditional
system
boundaries
expansion
“ the collection and
treatment of the annual
amount of (plastic) waste
produced by one inhabitant
of the Lombardia Region ”
(the amount of waste
collected and treated varies
between scenarios)
“the delivering of 152.1
litres of drinking quality
water to one inhabitant of
the Lombardia Region for 1
year”
functionally equivalent to
conventional waste
management treatments
to the WP scenario
(avoided burden approach)
Exists also a variant which
apply the cut-off approach
to the WP3 scenario
(1) WMS: Waste management system
(2) TPS / APS: Target product system / Alternative product system
(3) WP: Waste prevention
(4) BL: Baseline
The most important remark concerns the fact that, as showed in table 3.32 and in figure 3.13,
all the three investigated conceptual LCA models have led to the same difference in terms of
environmental impact between a baseline and a waste prevention scenario. This because all of
them are based on applying in different ways expansion of traditional system boundaries of
153
waste management oriented LCA to account for the same upstream life cycle processes.
Moreover, from an operative point of view, their practical application is translated in different
ways to implement these processes within the employed LCA support software.
Table 3.32: Comparison among the global warming impact indicator calculated through the investigated
models for all the examined scenarios
MODELS
WasteMAP LCA ISWP model SSWP model
Scenarios
 (WPS-BLS)
-1.5
-1.5
14
-14.8
-14.8
0.7
-13.2
-13.2
-13.2
Models comparison for global warming
Kg CO2 eq/F.U.
WasteMAP LCA
ISWP Model
20
15
10
5
0
-5
-10
-15
-20
SSWP Model
14.0
0.7
-1.5
-1.5
-14.8 -13.2
Baseline scenario
-14.8
-13.2
-13.2
DELTA (WPS-BLS)
Figure 3.13: Comparison among the global warming impact indicator calculated through the investigated
models for all the examined scenarios
Since the goal of the studies where these typologies of tools are applied is generally the
comparison between a scenario in which specific waste prevention activities are implemented
with respect to one or more baseline situations and not the exact accounting of the absolute
impact associated with a given scenario, this outcome can be viewed as a positive aspect. The
potential users could indeed in this way choose the model they consider more suitable for the
purposes of their study as well as the one they consider of easiest practical applicability.
If one wants to maintain separated the effects of the target product system(s) from those of the
alternative product system(s), then the Separate Scenarios Waste Prevention (SSWP) model is
the more proper. It also allows the actual accounting of the impacts associated with a given
scenario just because the two mentioned systems are separately considered within the scenario
154
in which they actually occur. An alternative for the accounting could be the use of the cut-off
version of the WasteMAP LCA model, whose practical applicability was however not
evaluated in this study.
The Waste MAP LCA model has appeared to be the one of more complex applicability with
respect to the other two compared models but however practicable. The major difficulties
could probably be associated with the need to define a proper secondary functional unit,
which could be a not so relative simple task as for the prevention activity investigated in the
previous analysis. Probably for many typologies of such activities it is impossible to proceed
to an its proper definition.
This relative complexity is however associated with the fact that the model aims at being as
much rigorous as possible and consistent with the ISO standards, by assuring a strong
functional equivalence of the scenarios to be compared through the additional secondary
functional unit. Despite this, waste prevention activities involving reduced consumption
cannot be however compared on a functionally equivalent basis with this model.
The utilisation of this model can thus be suggested to all those who need to carry out a
rigorous analysis in which such a strong equivalence of the scenarios has to be actually
assured.
The Integrated Scenarios Waste Prevention Model (ISWPM) instead can be employed if one
wished to utilise the avoided burdens approach without the need to deal with the discussed
difficulties associated with the application of the Waste MAP LCA model.
3.5 Modelling variant
In order to understand the extent to which the results are affected by the fact that also plastic
waste fractions whose amount is not subjected to change were considered in the previous
analysis at paragraph 3.4, all the three examined models will be now also implemented
considering only the prevented fraction that is represented by PET bottles. It is indeed
expected that the same result in terms of impact difference between scenarios shall be
obtained.
The principal difference with the previous analysis is that in baseline scenarios the only waste
to be managed through conventional treatments is constituted by 3.42 kg of PET bottles,
while in waste prevention scenarios a null amount of waste have to undergo to conventional
treatments.
155
Modelling principles will be the same adopted for the previous analysis as well as SimaPro
modules not affected by waste quantity. It follows a synthetic description of the main features
of the three LCA models.
3.5.1 WasteMAP LCA model
Baseline scenario
As already said, the only waste fraction that needs to undergo to conventional treatments is
represented by the 3.42 kg of PET bottles. Mass flows associated with this scenario are
showed in figure 3.14, which also gives an idea of the processes included in the system
boundaries.
The scenario is modelled exactly as in the previous variant, but considering only those
downstream processes associated with bottles treatment, in particular:

selection of separately collected bottles (2.63 kg);

PET bottles recovery (2.63 kg);

incineration of bottles in the residual waste (0.786 kg) and

incineration of recovery scraps (0.526).
The main module Baseline scenario accounts for these processes, except for scraps
incineration that is already considered in the PET recovery module, by recalling the respective
modules described in paragraphs 3.3.2 and 3.3.3.
Separately
collected
material
Input
waste
3.42 kg
PET bottles
3.42 kg
=77%
Recovered
material
=80%
2.63 kg
2.11 kg
Scraps
0.526 kg
0.786 kg
Incineration
1.31 kg
WasteMAP LCA model and respective ideal boundaries
156
Target product system and Alternative product system
The processes associated with the target product system and with the alternative product
system are not affected by the choice to consider only wasted PET bottles and thus the
respective burdens and impacts do not change. Those obtained in the previous calculation can
still be considered for this analysis.
Since a null amount of waste still have to be managed through conventional treatments after
the implementation of waste prevention, no any further analysis have to be performed for the
DOWN waste management system, that is the system that encompasses all those waste
treatments needed to handle the amount of waste still remaining after the implementation of
preventive activities.
The value of the impact indicator for waste prevention scenario can be obtained always
through equation 3.1.
Results
The value of the global warming impact indicator calculated for the waste prevention scenario
through equation 3.1 is reported in table 3.33 together with the contribution of each subsystem to its definition. This is also reported in comparison to the value obtained for the
baseline scenario in table 3.34 as well as the respective difference. In table 3.35 are finally
specified the contributions of the main processes to the impact of each sub-system and of the
baseline scenario. Figure 3.15 and 3.16 give a graphical representation of the results reported
in table 3.33 and 3.34.
Table 3.33: Global warming impact indicator calculated through the WasteMAP LCA model for each subsystem that contribute to define the overall impact of the waste prevention scenario and of the waste prevention
scenario itself
Sub-system
Indicator
0
DOWN WMS
15.5
UpTPS
0.05
UpAPS
-15.4
157
Table 3.34: Global warming indicator calculated through the WasteMAP LCA model for each analysed
Scenario
Indicator
-2.2
-15.4
-13.2
 (WPS-BLS)
Table 3.35: Contribution of main processes to the global warming impact indicator calculated through the
WasteMAP LCA model for each sub-system and for the baseline scenario
Scenario
Total
Plastic
recycling
Plastic
incineration
DOWN WMS
UpTPS
UpAPS
 (DOWN WMS-BLS)
-2.2
0
15.5
0.05
2.2
-3.1
0
3.1
0.9
0
-0.9
Tap
PET bottles
water, at
production
user
15.5
0.05
-
Global warming
kg CO2 eq/F.U.
Baseline scenario
(BLS)
0
Waste prevention
scenario (WPS)
DELTA (WPS-BLS)
-15.4
-13.2
-2.2
-5
-10
-15
-20
Figure 3.15: Global warming impact indicator calculated through the WasteMAP LCA model for each analysed
Global warming
(WPS)
kg CO2eq/F.U.
5
0
-5
UpAPS
-2.2
-10
-15.5
-UpTPS
DOWN WMS
-15
-20
Figure 3.16: Sub-systems contribution to the global warming impact indicator calculated through the
WasteMAP LCA model for each analysed scenario
158
As expected the absolute values of the impact indicator calculated for the two compared
scenarios are different from those obtained with the same model considering also the other
plastic fractions, while on the contrary their difference results to be the same (-13.2 kg CO2
eq.).
Further observations concerning the different impact of scenarios are the same that were made
from the previous analysis and are not reported here again.
On the basis of these results and of the conclusions concerning the previous comparative
analysis it can therefore be expected that also in this variant all the three investigated models
lead to the same results in term of impact difference between scenarios. Despite of this we
have however chosen to carry out this variant of the analysis also with the remaining two
models.
3.5.2 Integrated Scenarios Waste Prevention Model (ISWPM)
In order not to dull the exposition and considering that the modelling principles are identical
to the previous case in which all plastic fractions were included in the analysis, only the
graphical representation of the mass flows and of the processes to be considered in both
baseline and waste prevention scenarios are reported here (figure 3.17 and 3.18). Table 3.36
presents instead the obtained results.
Separately
collected
material
Potentially
produced waste
=
input waste
=
3.42 kg
=77%
Recovered
material
=80%
2.63 kg
2.11 kg
PET bottles
3.42 kg
Scraps
0.526 kg
0.786 kg
Incineration
1.31 kg
Figure 3.17: Mass flows within the waste management system and major processes included in the systems
boundaries of the baseline scenario modelled through the ISWP model
159
PET bottles
avoided production
3.42 kg
Tap water, at user
152.1 litres
Prevention PET bottles
3.42 kg
Potentially produced waste = 3.42 kg
>
input waste = 0 kg
Figure 3.18: Major processes included in the systems boundaries of the waste prevention scenario modelled
through the ISWP model
Table 3.36: Global warming impact indicator calculated through the ISWP model for each analysed scenario
Scenario
Total Plastic recycling Plastic incineration Prevention PET bottles
-2.2
-3.1
0.9
Waste prevention scenario (WPS) -15.4
0
0
-15.4
-13.2
3.1
-0.9
-15.4
 (WPS-BLS)
3.5.3 Separate Scenarios Waste Prevention Model (SSWPM)
According to the reasons mentioned in the previous paragraph, also in this case only the mass
flows and of the processes included in the analysis are shown in figure 3.19 and 3.20 as well
as the respective results in table 3.37.
Bottled water
supply
152.1 litres
(3.4 kg PET
bottles)
=77%
Recovered
material
Separately
collected
material
Input waste PET bottles
3.42 kg
3.42 kg
=80%
2.63 kg
2.11 kg
Scraps
0.526 kg
0.786 kg
Incineration
1.31 kg
Figure 3.19: Mass flows within the waste management system and major processes included in the systems
boundaries of the baseline scenario modelled through the SSWP model
160
Tap water supply
152.1 litres
Input waste
0 kg
Figure 3.20: Major processes included in the systems boundaries of the waste prevention scenario modelled
through the SSWP model
Table 3.37: Global warming impact indicator calculated through the SSWP model for each analysed scenario
Plastic
Plastic
Scenario
Total
recycling incineration
13.3
-3.1
0.9
0.05
0
0
-13.2
3.1
-0.9
 (WPS-BLS)
PET bottles Tap water,
production
at user
15.5
0.05
-15.5
0.05
3.5.4 Further comparative considerations
As showed in table 3.38 and in figure 3.21, the most important consideration concerns the fact
that the same impact difference between a baseline and a waste prevention scenario is
obtained not only when utilising different models but also when only the prevented waste
fraction is included in the analysis.
Table 3.38: Comparison among the global warming indicator calculated through the investigated models for all
the considered scenario variants
Scenarios
 (WPS-BLS)
MODELS
All plastic waste fractions
Only PET bottles waste
WasteMAP
ISWP
SSWP
WasteMAP
ISWP
SSWP
LCA
model
model
LCA
model
model
-2.2
-2.2
13.3
-1.5
-1.5
14
-15.4
-15.4
0.05
-14.8
-14.8
0.7
-13.2
-13.2
-13.2
-13.2
-13.2
-13.2
161
Models comparison for global warming
WasteMAP
LCA (AWF)
ISWP Model SSWP Model WasteMAP ISWP Model SSWP Model
(AWF)
(AWF)
LCA (OPBW)
(OPBW)
(OPBW)
20
14.0
Kg CO2 eq/F.U.
15
13.3
10
5
0.7
0.05
0
-5
-1.5
-1.5
-2.2
-2.2
-10
-15
-20
-13.2
-14.8
-13.2
-14.8
Baseline scenario
-13.2
-13.2
-15.4
-15.4
-13.2
-13.2
DELTA (WPS-BLS)
AWF: All w aste fractions; OPBW: Only PET bottles w aste
Figure 3.21: Comparison among the global warming indicator calculated through the investigated models for
all the considered scenario variants
This can be firstly explained by considering that the magnitude of the processes (and of the
respective burdens) modelling the treatments of not prevented waste fractions, such as HDPE
containers and polyolefines mix recovery processes in our case, remains constant between
baseline and waste prevention scenarios. Moreover, this can occur since those processes that
deal with both prevented and not prevented fractions, such as PET recovery and plastic
incineration, linearly answer to a variation (in this case a decrease) of the waste amount that
they have to manage. In the case in which some non linearity would be associated to waste
treatment processes, this aspect could potentially no longer occurs. Several attention has thus
to be put on which waste fractions can be actually disregarded when waste prevention
activities that involves different waste material streams are considered.
For instance, the plastic incineration process behaves as linear because it is modelled in such a
manner that the respective burdens are already associated with the treatment of only a single
material. The absence of non linearity should instead be verified when incineration is
modelled as a whole process that deals with multiple input waste materials, like it is generally
done in waste management oriented life cycle assessment. In this case it would indeed be
possible that the chemical or physical reactions which are involved in modelling the
incineration process lead to the occurring of some non linear mechanisms. If this would
happen, a possible solution just could be to build up an independent incineration process for
each waste material and then only account for prevented waste fractions in the analysis.
162
CHAPTER 4
LIFE CYCLE INVENTORY OF SCENARIOS
4.1 Introduction
After having recognized in chapter 3 that the three examined models lead to the same results
when carrying out a simplified analysis, we have chosen to investigate more thoroughly the
two typologies of drinking water supplying systems: bottled water and public network water.
This in order to evaluate if the environmental advantages assessed for the public network
water system remain unchanged when considering a more complete life cycle evaluation for
both systems, different subscenarios and a wider number of impact indicators. Moreover, a
second prevention activity, still associated with drinking water consumption, is analysed: the
introduction of a refilling system.
In particular, the Separate Scenarios Waste Prevention Model (SSWPM) proposed in chapter 2
is employed, since it allows to account for the effects of each delivering system within the
scenario in which it is actually utilised and therefore their comparison can be carried out. Not
prevented waste fractions are excluded from the analysis in order to focus on the
performances of the different delivering options and on their further comparison. Only the
processes involved in the management of the waste generated by the alternative systems are
therefore considered since, as also emerged in chapter 3, disregarding materials not subject to
prevention does not affect scenarios comparison if, in each of them, they are always managed
in the same manner.
As in chapter 3, the analysis is carried out with the support of the software SimaPro, one of
the most widespread tools utilised to perform LCAs of any kind of product and service.
4.2 Analysed scenarios and goal definition
Three baseline scenarios, characterized respectively by the utilisation of virgin polyethylene
terephthalate (PET), of 50% recycled PET and of polylactic acid (PLA) one-way bottled
164
Chapter 4. Life cycle inventory of scenarios
water are firstly assessed to be utilised as terms of comparison. The former is indeed assumed
to be representative of the current situation while the second and third represent two possible
evolutional scenarios for the Italian context. They are compared with two public network
water preventive scenarios in which purified groundwater from the tap (real case of Milan)
and purified surface water from public fountains (real case of Florence) are respectively
utilised. Finally, two refilling preventive scenarios which foresee, respectively, the utilisation
of glass and of PET refillable bottled water are considered. Table 4.1 summarises the most
important features of the scenarios that will be examined in this chapter.
The overall goal of the analysis is to evaluate if the investigated prevention activities, besides
reducing waste generation, are actually associated with better environmental performances
with respect to the different delivering options considered for one-way bottled water and, in
affirmative case, in which conditions this is assured.
In order to model bottled water scenarios, primary data concerning the productive process of a
medium size bottling company located in northern Italy are employed, while primary data
concerning the purifying and delivering systems of Milan and Florence are instead utilised to
model public network water scenarios. A further improvement of water quality is also
considered, at domestic level for the groundwater scenario and at public level for the surface
water scenario, with specific reference in this last case to the delivery of high quality water
from public fountains, currently taking place in Florence.
Table 4.1: Major features of the scenarios analysed in this chapter
Scenarios and
subscenarios
Water delivering options
Baseline scenario 1
One-way virgin
PET bottled water
Baseline scenario 2
One-way 50% recycled
PET bottled water
Baseline scenario 3
One-way PLA
bottled water
Waste prevention
scenario 1A
Waste prevention
scenario 1B
Purified groundwater
from the tap
(real case of Milan)
Purified surface water
from public fountains
(real case of Florence)
Typology of
packaging
packaging mix
composed by
2, 1.5 and 0.5
litres bottles
End of life options
for bottles/containers
77% recycling
23% incineration
77% recycling
23% incineration
Two subscenarios:
1) 100% composting and,
2) 100% incineration
1 reusable glass jug
(Recycling)*
9 reusable 1 litre
glass bottles
(Recycling)*
Waste prevention
1 litre glass bottles
Refillable glass bottled water
100% recycling
scenario 2A
used for 10 times
Waste prevention
1 litre PET bottles
Refillable PET bottled water
100% recycling
scenario 2B
used for 15 times
(*) The burdens of the recycling processes of containers employed in public network water systems are assigned,
for simplicity, to the upstream product systems
165
4.3 Functional unit and system boundaries
For all the investigated scenarios the functional unit (FU) is assumed to be:
“the management of the amount of (municipal) waste annually generated from the
consumption of drinking water by one Italian citizen”.
This amount is subject to changes, according to the scenario, for a constant amount of
drinking water consumption considered equal to 152.1 litres per inhabitant per year
(paragraph 4.5.1).
The fact of considering only the waste generated by the product systems associated with the
different delivering options, as specified in paragraph 4.1, makes this analysis a sort of
product oriented life cycle assessment viewed from a different perspective. We have however
chosen to utilise the waste management perspective as done up to now in this study in order to
give further practical examples of its applicability.
As a traditional waste management oriented life cycle assessment, the system boundaries will
include all the end of life treatments belonging to the municipal solid waste management
system required to deal with the waste generated by the investigated product systems. They
will be also expanded to include the whole upstream life cycle of the different delivering
options. Further details concerning which upstream processes and activities are included in
the boundaries will be given separately for each scenario in the corresponding paragraph.
4.4 Impact assessment categories and characterization methods
The Cumulative energy demand (CED) characterization method is firstly employed to carry
out the energetic assessment of the investigated scenarios. It allows to analyze energy
consumptions associated with all the life cycle stages of a system, considering either direct or
indirect utilisations. These lasts are the ones associated to the energy content of materials. The
CED energy indicator, expressed as MJ eq., quantifies therefore the whole amount of energy
potentially required by a given investigated scenario.
Moreover, three environmental impact categories, evaluated through the CML 2001 baseline
characterization method (Guinée, 2002), are considered: abiotic resources depletion, global
warming and eutrophication. The abiotic resources depletion category is chosen in order to try
to account for potential natural resources savings that are expected to be achieved through a
prevention activity. Global warming is instead considered in reason of its extreme relevance
166
among contemporary environmental issues. Finally the eutrophication category is considered
to evaluate if the use of detergents during bottles washing can give an important contribution
to its definition.
The only step of characterization is performed in this study in order to avoid the introduction
of subjectivity and uncertainty associated with normalization and weighting. It follows a brief
description of the considered environmental impact indicators.

Abiotic resources depletion
Abiotic resources are natural resources (including energy resources) such as minerals or fossil
fuels which are considered as non-living. The abiotic resources depletion indicator aggregates
all consumptions of these resources by means of characterization factors, the Abiotic
Depletion Potentials (ADPs), which are calculated for each resource on the basis of the
concepts of ultimate reserves and extraction rates. The ultimate reserve of a resource is the
still available amount of that resource, estimated for instance by multiplying its average
concentration in the primary extraction media (i.e. the earth’s crust) by the mass or volume of
these media (i.e. the mass of the crust) (Guinée, 2002).
Since the resource assumed as reference is antimony, the impact indicator is expressed in kg
of equivalent antimony (kg Sb eq.) and is calculated through the following equation:
Abiotic resource depletion (kg Sb eq.)   ADPi  m i
i
where:
ADPi = Abiotic Depletion Potential for the resource i (kg Sb eq./kg);
mi = amount consumed of the resource i (kg, or MJ for fossil resources).
The characterization factors for some of the several resources which contribute to the
definition of the indicator are showed in table 4.2 so as reported in the version 2.04 of the
CML 2001 baseline method implemented in SimaPro.
167
Table 4.2: Characterization factors (ADP) for some substances that contribute to the abiotic resources
depletion impact indicator so as reported in the CML 2001 baseline method implemented in SimaPro
Substance
Oil, crude, 38400 MJ per m3, in ground
Gas, natural, in ground
Gold, in ground
Silver, in ground
Platinum, in ground
Mercury, in ground
Cadmium, in ground
Tin, in ground
Gas, natural, 46.8 MJ per kg, in ground
Oil, crude, in ground
Lead, in ground
Coal, hard, unspecified, in ground
Coal, brown, in ground
Uranium, in ground
Copper, in ground
Zinc, in ground
Chromium, in ground
Sulfur, in ground
Nickel, in ground
Phosphorus, in ground
Manganese, in ground
Lithium, in ground
Fluorine, in ground
Iron, in ground
Chlorine, in ground
Titanium, in ground
Potassium, in ground
Aluminium, in ground
Magnesium, in ground
Bauxite, in ground
Calcium, in ground
Sodium, in ground
Energy, from coal, brown
Energy, from gas, natural
Energy, from oil
Energy, from coal
Energy, from uranium

Characterization factor (ADP)
18.4
1.87E-02
89.5
1.84
1.29
4.95E-01
3.30E-01
3.30E-02
2.25E-02
2.01E-02
1.35E-02
1.34E-02
6.71E-03
2.87E-03
1.94E-03
9.92E-04
8.58E-04
3.58E-04
1.08E-04
8.44E-05
1.38E-05
9.23E-06
2.96E-06
8.43E-08
4.86E-08
4.40E-08
3.13E-08
1.00E-08
3.73E-09
2.10E-09
7.08E-10
8.24E-11
6.71E-04
5.34E-04
4.90E-04
4.57E-04
6.36E-09
Unit
kg Sb eq. / m3
kg Sb eq. / kg
kg Sb eq / MJ
Global warming
The global warming indicator aggregates all greenhouse gases emissions by means of a
characterization factor represented by their Global Warming Potential (GWP) which
expresses the ratio between the increase of the infrared absorption due to the instantaneous
emission of 1 kg of a given greenhouse substance and that due to an equal emission of carbon
168
dioxide (CO2) which is assumed as the reference substance. The indicator is therefore
expressed in kg of CO2 equivalent (kg CO2 eq.) and is calculated as:
Global warming (kg CO 2 eq.)   GWPi  m i
i
where:
GWPi = Global Warming Potential for the substance i (kg CO2 eq./kg);
mi = mass of the substance i released in the environment (kg).
The values of GWP vary as a function of the time interval upon which the increase of the
infrared absorption is evaluated, and estimate are available for time horizons of 20, 100 and
500 years. For LCA study a long time horizon seems to be preferable but since along with its
increase also more uncertainties are introduced, the values referring to a time horizon of 100
years are generally adopted and the potentials are indicated as GWP100.
The values of the GWP100 characterization factors considered in this study are those reported
in the version 2.04 of the CML 2001 baseline method implemented in SimaPro but adjusting
the values associated with dinitrogen monoxide (N2O) and methane (CH4) with those reported
by the last IPPC report (IPPC, 2007). Table 4.3 summarises the most important substances
contributing to the definition of the impact indicator and the respective GWP value.
Table 4.3: Characterization factors (GWP100) for some substances that contribute to the global warming impact
indicator so as reported in the CML 2001 baseline method implemented in SimaPro
Characterization factor (GWP100)
kg CO2 eq./kg
Carbon dioxide, fossil (CO2)
1
Carbon dioxide, biogenic
0
Dinitrogen monoxide (N2O)
298 (IPPC, 2007)
Methane
25 (IPPC, 2007))
Substance

Eutrophication
Eutrophication substantially consists in the excessive increase of the environmental level of
macronutrients, the most important of which are nitrogen (N) and phosphorus (P), leading to a
potential increase of biomass production, especially in aquatic ecosystems. This in turn may
lead to oxygen level reduction because of biomass decomposition. The eutrophication
indicator aggregates therefore all those substances contributing to this phenomenon which are
mainly represented by nitrogen and phosphorus compounds. Moreover, since also the
169
oxidation of degradable organic matter (expressed as Chemical oxygen demand, COD) leads
to a decrease of the oxygen level in aquatic ecosystems, it is included in this category as well.
The aggregation is made through characterization factors represented by the Eutrophication
Potential (EP) of each substance which quantify their potential contribution to biomass
formation with respect to that of phosphate (PO43-). The indicator is therefore expressed in kg
PO43- eq. and is calculated through the following equation:
Eutrophication (kg PO 34- eq)   EPi  m i
i
where:
EPi = Eutrophication Potential for the substance i (kg PO43- eq./kg);
mi = mass of the substance i released to the air, water or soil (kg).
The eutrophication potentials of the present method are defined by assuming an unlimited
availability of the other nutrients required for biomass formation and are therefore
independent from their actual level in a particular location, in which a certain substance could
instead be a limiting factor for biomass growing. Table 4.4 summarises the substances
contributing to the definition of the eutrophication impact indicator and the respective
Eutrophication Potentials so as reported in the version 2.04 of the CML 2001 baseline method
implemented in SimaPro.
170
Table 4.4: Characterization factors (EP) for the substances contributing to the eutrophication impact indicator
so as reported in the CML 2001 baseline method implemented in SimaPro
Characterization factor (EP)
kg PO43- eq./kg
Ammonia
0.35
Ammonium carbonate
0.12
Ammonium nitrate
0.074
Ammonium, ion
0.33
COD, Chemical Oxygen Demand
0.022
Nitrate
0.1
Nitric acid
0.1
Nitric oxide
0.2
Nitrite
0.1
Nitrogen
0.42
Nitrogen dioxide
0.13
Nitrogen oxides
0.13
Phosphate
1
Phosphoric acid
0.97
Phosphorus
3.06
Phosphorus pentoxide
1.34
Substance
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4.5 Baseline scenario 1 (Utilisation of virgin PET one-way bottled water)
4.5.1 Waste generation and management
In order to define the amount of waste produced and to be managed under this scenario, the
same procedure adopted for the estimate of the prevention potential adopted in previous
paragraph 3.2.2 is utilised, but considering also the contribution of other primary packaging
materials (caps and labels), as well as of secondary packaging, constituted by bundle heatshrink films. The whole procedure is reported here again for clarity.
First of all, by considering the data concerning the volume of packaged water consumed in
Italy for the year 2008 by typology of packaging (Bevitalia, 2009), reported in table 4.5, and
an average population for the same year of 59,832,179 inhabitants10, it is possible to estimate
the respective specific consumptions which, with regard to the only volume of water
packaged in PET bottles, amount altogether to 152.1 litres/inhabitant/year.
Table 4.5: Volume of packaged water consumed in Italy during the year 2008 by typology of packaging, both in
absolute and specific terms (Elaboration on data from Bevitalia (2009))
Bottled water consumptions - packaging mix – Italy, year 2008
PET bottles - 2 litres
PET bottles - 1.5 litres
PET bottles - single serve (≤ 0.5 litres)
PET bottles - total
Glass bottles
PC* and PET jugs, bio-bottles, brick
Total
(*) PC: Polycarbonate
576.4
7,833.6
690
9,100
2,070
350
11,520
9.6
130.9
11.5
152.1
34.6
5.8
192.5
%
5
68
6
79
18
3
100
% on PET
bottles only
6.3
86.1
7.6
100
The packaging mix specified for PET bottles is assumed to well represent the domestic
consumption, considering that big size bottles (1.5 litres and 2 litres ones) are quite
exclusively employed for this purpose and that the inclusion of the whole small share of little
size bottles (only 6%), widely employed in vending machines, can only marginally affect the
overall results.
10
Calculated by averaging the resident population at 1st January and 31 December 2008, respectively equal to
59,619,290 and 60,045,068 (ISTAT, 2010a).
172
By combining these data with the average masses of primary and secondary packaging
materials (bottles, caps, labels and bundle heat-shrink films) characterizing the three
typologies of PET bottles sizes, provided in Federambiente (2010) and reported in table 4.6, it
is therefore possible to calculate the amount of waste generated by each one of these items
under the present scenario, which altogether results equal to about 4.1 kg/inhabitant/years.
The results of these calculations are reported in table 4.7.
Table 4.6: Average masses of PET bottled water primary and secondary packaging materials (Federambiente,
2010)
HDPE
Paper
LDPE
PET bottles size Bottles mass
Cap mass Label mass Bundle heat-shrink film mass
(litres)
(g)
(g)
(g)
(g)*
2
33.42
1.72
0.52
26
1.5
32.55
2.06
0.57
21.8
0.5
18.06
2.45
0.4
10.5
(*) Each bundle contains 6 bottles
Table 4.7: Amount of packaging waste generated by the consumption of one-way PET bottled water in baseline
scenario 1
PET
bottles size
(litres)
2
1.5
0.5
Total
Share
(%)
6.3
86.1
7.6
100
LDPE
Heatshrink
films
(litres/inhab/y) (g/inhab/y) (g/inhab/y) (g/inhab/y) (g/inhab/y)
9.6
161
8.28
2.5
20.9
130.9
2,841.1
179.8
49.8
317.1
11.5
416.5
56.5
9.23
40.4
152.1
3,418.6
244.6
61.5
378.4
Total waste
3.42
0.245
0.0615
0.378
(kg/inhab/year)
Specific
consumption
PET
bottles
HDPE
caps
Paper
labels
Prevention
potential
(g/inhab/y)
4,103.1
4.103
As described in paragraph 3.3.2, bottles are assumed to be separately collected for recycling
with a 77% efficiency, while heat-shrink films, which are here considered to be part of the
polyolefines mix waste flow, with a 33% efficiency. The residual fraction is instead assumed
to be incinerated in a waste to energy plant. Remembering afterwards that the efficiencies of
PET and polyolefines mix recovery processes were considered to be 80% and 60%
respectively, it is possible to define the waste flows within the management system and,
therefore, the amount of waste handled by a given process, as showed in figure 4.1. In
carrying out mass balances, caps and labels are assumed, for simplicity, to be directly routed
to incineration as a not separately collected fraction, even if a certain amount of them is
173
actually part of the scraps generated by the PET recovery process, where they are separated
from bottles.
Separately
collected
material
=77%
PET bottles
3.42 kg
Recovered
material
=80%
2.63 kg
2.11 kg
HDPE caps1
0.245 kg
Input
waste
4.1 kg
LDPE heatshrink films
0.378 kg
=33%
=60%
0.125 kg
0.0749 kg
Total=2.76 kg
Total=2.18 kg
1
Paper labels
0.0615 kg
Paper incineration
0.0615 kg
Virgin PET
granules
avoided
production
(1.71 kg)2
Wooden
planks
avoided
production
0.0749 m3
Scraps
0.576 kg
1.28 kg
Plastic incineration
1.85 kg
(1) Even if 77% of caps and labels would be separately collected with bottles and then
sent to incineration as recovery scraps, they are assumed, for simplicity, to be directly
routed to incineration.
(2) A substitution rate of 1:0.81 is considered (paragraph 3.3.2)
Figure 4.1: Waste flows within the management system for baseline scenario 1
According to the balances results, the processes that occur in the waste management system
and that have to be modelled are therefore:

selection of separately collected bottles and heat-shrink films (2.76 kg),

recovery of selected PET bottles (2.63 kg),

recovery of selected LDPE heat-shrink films (0.125 kg),

incineration of caps and of not separately collected bottles and heat-shrink films (1.28
kg),

incineration of labels (0.0615 kg),

The processes of plastic materials selection, recycling and incineration are modelled in a life
cycle perspective as described in paragraph 3.3.2 and 3.3.3, to which we refer for further
details.
174
The new module Paper incineration is instead created to model labels incineration. This is
made with the same approach employed in the paragraph 3.3.3 but considering variations of
waste specific burdens associated with the different elemental composition and heating value
of paper with respect to plastic (table 4.8).
Table 4.8: Elemental composition of paper
%W
C Cl H O N S Ashes Total
43.7 0.7 6 43.4 0.2 0.2 5.8
100
%WW
Ashes Moisture Volatiles
5
14
81
Total
100
In particular, these variations concern airborne emissions, reagents consumptions for flue gas
cleaning, production of residues and the amount of electricity and heat generated by the
process. They are summarised in table 4.9 except for airborne emissions which are reported in
table B.1 of appendix B.
Table 4.9: Summary of waste specific material and energy inputs and outputs of the paper incineration process
Amount
(g/kgWW)
7.3
Flue gas volume (m3n dry gas/kgWW) @ 11% O2
Reagents consumption:
29.1
Activated carbon
2.9
Urea CO(NH2)2
7.4
Bottom ashes generation
62.3
of which:
Over-sift to inert material landfill
8.1
54.2
55.9
Fly ashes generation
21.8
28.3
Air pollution control residues generation
26.3
Energy:
Electricity for bottom ashes sorting (kWh/kgWW) 2.5×10-4
Electricity production (avoided)1 (kWh/kgWW)
0.89
1,2
Heat production (avoided) (kWh/kgWW) 0.0016
(1) A paper lower heating value of 13,223 kJ/kgWW is considered
(2) Distribution and heat exchanging losses included (20%)
Material and energy flows
Since this baseline scenario is characterized by the utilisation of one-way virgin PET bottled
water, the most important upstream life cycle processes involved in its supplying have to be
included in the analysis because their magnitude is subject to change among the examined
175
scenarios. A detailed inventory of this product system will be therefore carried out in the
following paragraph.
4.5.2 Life cycle inventory of one-way virgin PET bottled water
System description
In order to understand mass and energy flows involved in the productive process of bottled
water we have visited and examined the bottling plant of a medium size company sited in
northern Italy, which will be now described to clarify the typology of system under
investigation. Moreover, data concerning this specific reality will be employed to carry out
the inventory. Where necessary, the provided information are completed with information
found in the literature.
The examined company commercializes mineral water packaged either in PET disposable
bottles in the format of 0.5 litres and 1.5 litres, or in glass refillable and disposable bottles in
the format of 0.5 litres, 0.75 litres and 1 litre. During the year 2009 its production amounted
to about 80,000,000 litres of which around 70% in PET bottles and the remaining 30% in
glass bottles (about 2/3 flat and 1/3 sparkling).
Water employed for bottling is collected from two springs emerging from the rock at an
altitude of 750 and 650 meters, respectively. At the springs, water is conveyed into a basin
and from this to the plant through one 70 mm stainless steel pipe of the length of 200 meters
for the higher spring and of 100 meters for the lower one.
At the plant the water of the higher spring is stored in two stainless steel reservoirs with the
capacity of 200 m3 and an height of 6 meters, while the one drawn from the lower spring is
stored in a unique reservoir with the same characteristics. Reservoirs are in turn connected,
always through stainless steel pipes, to the two bottling lines sited in the plant. Other 10
reservoirs of the volume of 18 m3 each one and 3 meters tall, store the incoming volume of
water exceeding the storage capacity of the three main reservoirs, and their content is
employed as service water for circuits chilling, machineries washing and so on.
As mentioned above, two bottling lines are placed at the plant, one for PET bottles that will
be described now, and another for glass bottles which will be described in paragraph 4.10.2
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PET bottles are manufactured starting from preforms through a stretch-blow moulding
process which takes place at the plant. Preforms are the compact form of the future bottles
and are similar to test tubes with an upper part constituted by the threaded neck, not destined
to be modified by the blowing process, and a lower tubular part instead destined to be blown
in apposite moulds to acquire the definitive shape of the bottle. Preforms are manufactured
through injection moulding of melted PET granules in external facilities.
The company employs 1.5 litres preforms with a mass of 27 g for still water and of 32 g for
sparkling water, while 0.5 litres preforms have a respective mass of 12.5 g and 15 g.
The process begins with withdrawing of preforms from the respective container through an
elevator which conveys them towards a rectifier which orientates preforms with the neck
faced upward to allows their introduction into the blowing machine. Here preforms are firstly
heated at the temperature of about 100-120°C while performing a circular pathway around a
certain number of infrared lamps batteries, becoming suitable to the next stage of blowing
and, at the same time, sterilized, with consequent no need of a disinfection stage. They are
then placed into aluminium moulds, which are the reverse shape of the bottles, to be blown.
The blowing process is articulated in two stages: the first is the one of stretch and preblowing, where a stretch bar lengthens the material in axial direction while low pressure
compressed air inflation (10-15 bar) widens it in radial direction, towards mould internal
surface. A next stage of high pressure blowing gives to the bottles their definitive shape
through inflation of compressed air at the pressure of 27 for 0.5 litres bottles and of 32 bar for
1.5 litres bottles. Bottles cool instantaneously when adhering to moulds surface since between
their internal and external surface an interspace is placed in which a chilling liquid composed
by water and ethylene glycol at the temperature of about 4-5 °C circulates.
Afterwards bottles are transferred to the filler machine while their bottom is further cooled by
means of crossed water jets in order to avoid its deformation which could occur during the
filling stage if the material was still too warm.
The process continues with bottles capping by means of high density polyethylene (HDPE)
closures provided with a tamper evidence band, of the weight of 1.87 g both for 0.5 and 1.5
litres bottles.
After this stage, bottles pass through an electronic inspector which verifies bottles conformity
and in particular the presence of the cap and the right filling level. If these requirements are
177
not satisfied, the inspector orders the opening of a gate making bottles to fall down and
removing them from the main flow.
The process goes on with the labelling stage where an apposite labellers machine wraps
around the bottles a pre-cut printed paper label by applying two narrow vertical lines of hotmelt glue, one to the bottle and one to the trailing label edge, minimizing glue consumption.
Hot-melt is drawn from a tank where it is kept at the temperature of about 140°C by electric
resistances. The weight of a label is about 1.5 g and 0.514 g for 1.5 and 0.5 litres bottles
respectively.
A further electronic inspector verifies the correct labelling and in negative case removes
bottles from the main stream with a mechanism analogous to the one discussed above.
Successively bottles are arranged in groups of 6 each one, wrapped with a low density
polyethylene (LDPE) heat-shrink film of 65 m thickness and passed through a oven where
electric heaters warm the film at the temperature of about 220-240 °C making it to shrink and
adhere to bottles, originating the bundle, which represent the most common commercialized
unit of PET bottled water.
The average mass of LDPE heat-shrink film employed for the bundle is equal to 24.5 and 18.5
grams for 1.5 and 0.5 litres bottles respectively.
To the bundles of 1.5 litres bottles, one handle is then applied. It is constituted by a
transparent polypropylene adhesive tape strip of about 45 cm in length and 2.5 cm in width,
coupled in its central part with a printed cardboard strip of about 20 cm in length and of the
same width. An apposite handling machine is employed for this operation.
The last process stage is palletization, which has the purpose to build up the standard transport
units of bottled water. Bundles are indeed charged on pallets in a precise number of
overlapping layers constituted by a precise number of bundles and separated each other by a
cardboard interlayer. In particular, for the examined plant, standard EUR-EPAL pallets with
dimensions 80×120 cm and about 22 kg weight are employed and charged, in the case of 1.5
litres bottles, with 4 layers of 21 bundles each one, for a total of 504 bottles and 3 interlayer.
For 0.5 litres bottles, 7 layers of 36 bundles each one are instead charged, for a total of 1,512
bottles and 6 interlayer. The mass of one interlayer is equal to about 600 grams. The
examined company does not commercialize 2 litres bottles but we have recognized how the
common loading practice for this typology of containers and pallets, foresees the charging of
4 layers of 19 bundles each one for a total of 456 bottles and 3 interlayer.
178
Bundles are therefore grouped on a platform from which they are drawn and transferred on
the pallet when the number of units required for the composition of 1 layer is reached. The
operation is repeated until all the layers required for pallet completion are overlapped.
On the upper layer a protective film of low density polyethylene (LDPE) is placed while, with
the same purpose, the whole charge is wrapped with a linear low density polyethylene
(LLDPE) stretch-film. The weight of the former is about 175 grams while that of the latter is
about 245 grams, and can be considered valid for all containers size since pallets load reaches
more or less the same height for all of them, in order to allow truck or trailer truck charging.
By means of a forklift truck, pallets are finally drawn and stocked or charged on trucks or
trailer trucks for their delivering to retailers. The company owns five trucks with a full-load
mass of 25 tonnes and a load capacity of 15 pallets, and two trailers which can be combined
with trucks to reach a full-load mass of 44 tonnes and a load capacity of 35 pallets. In some
cases transportations are also entrusted to external companies. During vehicles return trip, the
empty pallets are instead transported back to be employed again for next deliveries.
The filler machine undergoes daily a sequence of external washings with an alkaline detergent
solution, an acid detergent solution and a disinfectant solution respectively. Moreover a
weekly washing of its internal circuits with a CIP (cleaning in place) system is carried out
trough the utilisation of a solution of a caustic detergent and a peracetic acid based
disinfectant solution. Wastewaters are collected and sent to a little depuration plant where the
sewage is roughly screened and its pH neutralized through injection of carbon dioxide.
It is worth to notice how the use of preforms has became irreplaceable for bottling companies,
at least for medium-large ones which can afford the expense for the purchasing of the blower
machine. The main advantage is indeed the possibility to carry out their transportation in
capacious cardboard containers (named as octabins) which can contain more than 20,000
pieces. This allows to avoid transportation of the complete bottle from producers to users,
which would have the consequence of drastically increase the number of transportations
cycles required for the delivering of the same amount of product.
179
System boundaries
On the basis of the collected information about the productive framework of bottled water and
of the data that have been possible to obtain, we have defined the boundaries of the
investigated system, considering the following processes:

production of primary packaging materials: from extraction and preparation of needed raw
materials to the production of the packaging itself including preforms and caps moulding
and manufacturing of paper for labels. Fabrication of glue employed for labelling is not
included due to lack of data and to its marginal contribution as input mass (less than
0.32%).

production of secondary packaging materials: also in this case considering the production
of raw materials and the manufacturing processes of heat-shrink films employed for
bottles wrapping into the bundle. Also production of adhesive tape film and of cardboard
strip for handle is considered, together with their disposal which were not considered in
the waste management system for reasons of simplicity.

production of transport packaging materials: fabrication of the materials employed in the
manufacturing of pallets (wooden planks and nails) and of cardboard for interlayer.
Production of raw materials for stretch-films and their conversion are included as well.

operations at the bottling plant including preforms stretch blow moulding, containers
filling, capping, labelling, packaging and palletization. Washing of the filler machine is
also considered even if it will be recognized to give a marginal contribution to the results.

end of life treatments of the materials which are not considered to be handled by the
municipal waste management system: recycling of pallets materials, of stretch-films and
of interlayer.

transportation of packaged water from bottling plant to retailers and from retailers to
consumers houses are finally accounted for. Transportation of packaging materials to the
bottling plant are instead neglected for the high variability of involved transport distances.
180
Burdens associated with the life cycle of capital goods such as infrastructures and machineries
are not included. The respective processes give indeed generally a small contribution to the
results since their burdens are averaged on the whole life span of the good.
Figure D.1 represents the major upstream life cycle processes included in the scenario under
investigation and that will be described during the present inventory.
Reference flow
Since the function of the system under investigation is the production and delivering of
bottled water to Italian domestic consumers, the inventory is carried out by considering as a
reference flow “1 litre of one-way bottled water produced and delivered to consumers with
the packaging mix specified in table 4.5”. For this reason, all inputs and outputs have been
associated with this flow.
Data sources
Data concerning packaging materials masses, are found in the literature or provided by the
examined bottling plant. Primary data from the same reality regarding energy and main raw
materials consumptions for bottling plant operations were also utilised. If not otherwise
specified, inventory data concerning raw materials production and energy generation
employed in the present inventory are those provided by the modules of the widespread
Ecoinvent database, implemented in the software SimaPro.
Detailed inventory
Primary packaging materials manufacturing
Primary packaging materials are represented, other than by the bottles themselves, also by
HDPE caps and paper labels.
The amount of these materials required for the delivering of 1 litre of bottled water by means
of the three typologies of container belonging to the considered packaging mix, can be
calculated starting from the masses employed for the definition of the amount of waste
generated in the present scenario (paragraph 4.5.1), reported again in table 4.10. For
completeness, also the quantity of glue utilised for labelling is reported in the table even if the
burdens of its production process have been neglected in this study because of data lacking
181
and in view of the very small magnitude of glue as input mass. Consumptions of glue for the
labelling of 0.5 litres and 1.5 litres bottles refer to the examined bottling plant. The value
provided for 1.5 litres bottles is then also supposed to be valid also for 2 litres ones.
Table 4.10: Average masses of PET bottled water primary packaging materials (Federambiente, 2010)
PET
HDPE
Paper
Bottles size
Glue mass
bottles mass Cap mass label mass
(litres)
(g)
(g)
(g)
(g)
2
33.42
1.72
0.52
0.1
1.5
32.55
2.06
0.57
0.1
0.5
18.06
2.45
0.4
0.05
Just by dividing these values for the respective container capacity and by multiplying them for
the container share in the packaging mix, it is possible to calculate the amount of material
required material required by the system with respect to the reference flow, as reported in
table 4.11. For example, the mass of PET required to deliver 1 litre of water through 1.5 litres
bottles expressed with respect to the reference flow is equal to:
M PET_1,5 litres 
32.55 g/bottle 86.1

 18.7 g/litre
1.5 litre/bottle 100
By summing up the weighted results obtained from these calculations, it is then possible to
define the total amount of each material required by the system under investigation, as
showed in the last row of table 4.11. These values are those which have to be introduced in
the software.
Table 4.11: Primary packaging materials masses expressed with respect to the reference flow for baseline
scenario 1
Bottles size Share
(litres)
(%)
2
6.3
1.5
86.1
0.5
7.6
Total
Mass with respect to the reference flow (g/litre)
PET
HDPE
Paper
bottles
caps
labels
1.058
0.0545
0.0165
18.7
1.18
0.327
2.74
0.372
0.0607
22.5
1.61
0.404
As early described, PET bottles are manufactured through injection moulding of bottle-grade
PET granules into preforms. In this process granules are melted at the temperature of 270-280
°C and injected into a cooled mould (≤ 20°C), which has the reverse shape of the preform
182
(TNO, 2010). Injected preforms are then stretch blow moulded into bottles at the bottling
plant.
Inventory data employed to model virgin PET granules production are those provided in the
module Polyethylene terephtalate, granulate, bottle grade, at plant/RER available in the
Ecoinvent database. The module describes the production of bottle grade PET, which is
obtained by submitting amorphous PET to a further polymerisation in the solid state to
increase its molecular weight, making in this way the material suitable to the further injection
moulding conversion process. Amorphous PET is, in turn, produced through the
polymerisation in the liquid phase of BHET (bis-hydroxyethyl terephtalate) obtained from the
reaction of esterification of purified terephtalic acid (PTA) with ethylene glycol (EG) (Liebich
and Giegrich, 2010).
The module accounts for material and energy inputs, airborne and waterborne emissions,
treatments of generated waste and, in a life cycle perspective, an estimate of the burdens
associated with facilities building and dismantling.
For the modelling of the conversion process of PET into preforms, the Injection
moulding/RER dataset available in Ecoinvent is considered as source of inventory data.
The two mentioned processes are employed to build up the new module PET preforms, in
order to model the manufacturing processes of the three different sizes of preforms considered
in this scenario. As specified in the database, a conversion efficiency of PET granules into
preforms equal to 99.4% has been considered to account for process losses. Therefore the
module is utilised to account for the burdens associated with the production of 22.5 g of PET
preforms, starting from 22.6 g of virgin PET granules. Moreover, as specified in the database,
standard transport distances of granules to the conversion plant equal to 100 km by lorry and
200 km by rail are finally considered.
The conversion process of preforms into bottles has not been modelled separately because, as
already explained, in the majority of cases, this stage take place at the bottling plant and the
associated burdens will be considered into the respective module.
HDPE caps are manufactured, as well as preforms, through injection moulding of melted
HDPE granules by means of an injection press.
Polyethylene is a thermoplastic polymer resin constituted from long chains of ethylene
monomers. In particular, high density polyethylene is a specific type of polyethylene with a
density greater than 940 kg/m3 and is produced through the polymerisation of ethylene in
183
normal pressure conditions and at relatively low temperatures (20-75 °C). Its high density is
due to the presence of big crystalline regions in the structure that is possible thanks to the
relatively low content of side branches on the main chain, the majority of which are short
ones (Boustead, 2005a; Hischier, 2007a).
Inventory data employed to model HDPE granules production are those provided in the
Ecoinvent dataset Polyethylene, HDPE, granulate, at plant/RER which just models the
polymerisation process of ethylene under normal pressure and temperature conditions.
With the same methodology used to model preforms manufacturing, the new module HDPE
caps is built up in the software to model the production through injection moulding, of 1.61 g
of caps starting from 1.62 g of virgin HDPE granules.
In this study bottles labels are considered to be constituted, for simplicity, only from paper,
even if in the market also plastic labelled bottles (LDPE or PP) can be found. This
simplification is widely acceptable if considering the little contribution of the life cycle of
labels material to the impact categories considered in this study (see chapter 5 and appendix
E). Moreover a brief investigation among the main brands of Italian bottled mineral waters
(table A.1 in appendix A) has highlighted the wider utilisation of paper labels with respect to
plastic ones.
According to Hischier (2007b), two big groups of graphical papers can be identified in the
market (other than newsprint paper): wood containing papers (or mechanical papers) and
woodfree papers (or fine papers). For the first typology, less than 90% of the fibres are
derived from chemical pulp, while for the second typology at least 90% of the fibres are
derived form chemical pulp. A further subdivision can be made between uncoated and coated
papers in the case paper surfaces are coated or not with a coating mineral like kaolin or
calcium carbonate.
Paper employed for labels manufacturing is evidently uncoated, but no information are
available regarding its nature (woodfree or wood containing). For this reason and in order to
assign the least possible environmental drawbacks to the bottled water system, we have
decided to employ the typology of paper which the smallest environmental impact to the
scenario, with respect to the impact categories considered in this study. This is resulted to be
wood containing paper, represented by the Ecoinvent module Paper, wood-containing,
supercalendered (SC), at regional storage/RER which is thus employed to model the
production of 0.404 g of paper and its transportation from the paper mill to the regional
184
distributor. The reason of this choice is the fact that if also in this conditions the use of public
network water results to be environmentally better performing with respect to the use of
bottled water, of course this would be valid also in the case in which a more impacting
typology of paper was actually utilised.
Printing and cutting of paper foils is neglected due to lack of data. Anyway this omission is
considered to involve negligible effects on the overall results, always according to the small
contribution given by labels life cycle to the considered impact indicators.
The module Primary packaging materials is finally built up, by recalling the modules
described up to now, in order to model the burdens associated with the processes of primary
packaging materials manufacturing required to deliver 1 litre of PET bottled water.
Secondary packaging materials manufacturing
Secondary packaging materials are represented by LDPE heat-shrink film for bottles
wrapping up into the bundle and by handle materials: polypropylene (PP) adhesive tape
coupled with a cardboard strip in its central part (only for 1.5 and 2 litres bottles)
As done before, the amount of each one of these materials expressed with respect to the
reference flow of this inventory, can be calculated by dividing the mass of each single
secondary packaging item, reported in table 4.12, by the volume of water contained in each
bundle and by finally multiplying it for the share of the respective container format within the
packaging mix. For example the mass of LDPE heat-shrink film required to deliver 1 litre of
water through 1.5 litres bottles expressed with respect to the reference flow is equal to:
M LDPE_1,5 litres 
21.8 g/bundle
86.1

 2.09 g/litre
6 bottles/bundle  1.5 litres/bot tle 100
By summing up the weighted results it is then possible to calculate the total mass of each
material required to deliver 1 litre of water through the packaging mix, as presented in the last
row of table 4.13.
The values of the masses considered for heat-shrink film are those provided in Federambiente
(2010), while those concerning adhesive tape and cardboard handle refer to the examined
plant.
185
Table 4.12: Average masses of PET bottled water secondary packaging materials
Bottles size LDPE heat-shrink film Handle PE adhesive tape Handle cardboard
(litres)
(g)
(g)
(g)
2
26
0.535
1.45
1.5
21.8
0.535
1.45
0.5
10.5
not used
not used
Table 4.13: Secondary packaging materials masses expressed with respect to the reference flow for baseline
scenario 1
Mass with respect to the reference flow (g/litre)
Bottles size Share
LDPE
Handle PP adhesive tape Handle cardboard
(litres)
(%) heat-shrink film
2
6.3
0.14
0.00282
0.00765
1.5
86.1
2.09
0.0512
0.139
0.5
7.6
0.27
not used
not used
Total
2.49
0.054
0.146
LDPE heat-shrink film is manufactured through extrusion of LDPE granules. These lasts are
melted into an heated cylinder where a screw conveys them towards a die which gives the
desired form to the emerging plastic mass, such as film or profile (Hischier, 2007a).
Low density polyethylene is a particular type of polyethylene with a density smaller than 940
kg/m3 which is produced through the polymerisation of ethylene with a high pressure process
(up to 300 MPa) and at temperatures up to 300°C. Its lower density with respect to HDPE is
associated with a minor presence of crystalline regions in the material because of the higher
number of long and short side branches on the main chain of the polymer (Boustead, 2005c;
Hischier, 2007a).
Inventory data concerning the manufacturing of virgin LDPE granules by means of the high
pressure and high temperature polymerisation process are found in the Ecoinvent module
Polyethylene, LDPE, granulate, at plant/RER, while for the conversion process of LDPE
granules into packaging film, the module Extrusion, plastic film/RER, taken from the same
database, is employed. This last process is characterized by a conversion efficiency equal to
97.6%. Considering the same transport distances of the injection moulding process, a new
module, Bundle heat-shrink film, is created in the software to account for the burdens
associated with the production of 2.49 g of LDPE heat-shrink film starting from 2.55 g of
virgin LDPE granules.
The process of film printing is not considered within this study because of data lacking.
186
We have supposed that also polypropylene (PP) adhesive tape is manufactured through
extrusion of virgin PP granules. This material is a thermoplastic resin obtained through the
polymerisation of propylene monomers. Manufacturing processes are oriented to maximise
the formation of the isotactic form of the polymer (all CH3 groups oriented on the same side
of the polymeric chain) because of its superior properties with respect to the other existing
forms (syndiotactic and atactic) (Boustead, 2005d).
Life cycle data concerning virgin propylene granules manufacturing are taken from the
Ecoinvent module Polypropylene, granulate, at plant/RER and the module Handle adhesive
tape is built up to model the production of 0.054 g of PP film through the extrusion of 0.055 g
of PP granules (Extrusion, plastic film/RER).
Production of the adhesive material and of the tape itself has not been possible to be modelled
but this simplification is expected to bring negligible effects on results due to the small
amount of material involved.
To model the manufacturing of 0.146 g of cardboard of the handle strip, the dataset
Whitelined chipboard, WLC, at plant/RER is chosen, because it is resulted to be the typology
of cardboard with the lowest environmental impacts with respect to the indicators considered
in this study. This probably because it contains 80% recycled pulp, especially in its internal
layers. The top layer is made, on the contrary, from bleached chemical pulp (Hischier,
2007b).
As in the case of labels, the processes of paper cutting and printing are not considered on the
basis of the same consideration concerning their minimal contribution.
Since the end of life treatments of handle materials were not included in the waste
management system for reasons of simplicity, they are therefore considered at this stage of
the analysis. In particular both the PP adhesive tape and the cardboard strip are assumed to be
incinerated. The burdens and the modules associated with these processes were already
described in paragraphs 3.3.3 (Incineration plastic) and 4.5.1 and (Incineration paper).
The module Secondary packaging materials is therefore established to model the buredens
associated with the production of the amounts of secondary packaging materials required to
deliver 1 litre of bottled water through the packaging mix, by recalling the single modules
described up to now.
187
Transport packaging materials life cycle
As already specified, transport packaging materials are those utilised to build up the typical
transport units of bottled water: wooden pallets, cardboard interlayer, LLDPE stretch-films
and LDPE top-layer films employed to wrap up the pallet load.
The masses of these materials are reported in table 4.14 and refer to the examined bottling
plant. As already explained during system description, they can be considered similar for all
the considered container sizes.
Table 4.14: Average masses of PET bottled water tertiary packaging materials
Bottles size Cardboard interlayer LLDPE stretch-film LDPE top-film Pallet
(litres)
(g)
(g)
(g)
(units)
2 – 1.5 – 0.5
600
245
175
1
To define the amount of each materials required to deliver 1 litre of water through the
packaging mix, the values of table 4.14 have to be divided by the total volume of water
transported by one pallet, multiplied by the share of the respective container typology within
the packaging mix and finally summed up, as showed in table 4.15.
The volume of water transported by one pallet can be defined by remembering that pallets are
charged with the following criteria and that one cardboard interlayer is placed between each
layer:

0.5 litres bottles: 7 layers by 36 bundles for a total of 1,512 bottles and 756 litres loaded,

1.5 litres bottles: 4 layers by 21 bundles for a total of 504 bottles and 756 litres loaded,

2 litres bottles: 4 layers by 19 bundles for a total of 456 bottles and 912 litres loaded.
As consequence, for instance, the total mass of cardboard interlayer required for the
transportation of 1 litre of water packaged within 1.5 litres bottles, expressed with respect to
the reference flow is equal to:
M CARDBOARD_ 1,5 litres 
600 g/interlayer  3 interlayer /pallet 86.1

 2.05 g/litre
(21  4  6  1.5) litres/pallet
100
188
An exception is represented by the number of pallet units. In fact, according to Creazza and
Dallari (2007), we have assumed that one pallet can be utilised on average for 20
transportation cycles before damaging and therefore the number of input pallet units must be
scaled down by 1/20. Always in the case of 1.5 litres bottles, this means that the number of
pallets units required for the transportation of 1 litre of water, expressed with respect to the
reference flow are equal to:
No. pallet 
1 pallet unit
1
86.1


 5.69  10 5 pallet units/litr e
(21  4  6  1.5) litres/pallet/trip 20 trips 100
Table 4.15: Tertiary packaging materials masses expressed with respect to the reference flow for baseline
scenario 1
Mass with respect to the reference flow
Bottles size Share Cardboard interlayer LLDPE stretch-film LDPE top-film
Pallet
(litres)
(%)
(g/litre)
(g/litre)
(g/litre)
(units/litre)
2
6.3
0.125
0.0170
0.0122
3.47×10-6
1.5
86.1
2.05
0.279
0.199
5.69×10-5
0.5
7.6
0.361
0.0246
0.0176
5.01×10-6
Total
2.54
0.321
0.229
6.54×10-5
Actually, the fate of a damaged pallet could also be undergo repair operations and its
subsequent reintroduction in the supply chain, in place of direct recycling or disposal. The
choice between repair or recycling/disposal is the number of broken elements, which in
general must not be greater than three, in order that repair is already economically convenient
(Creazza and Dallari, 2007). Despite of this in the present study no repair operations are
considered to be carried out in pallets life cycle, while recycling is considered as end of life
option, as will be described forth.
The amount of raw materials employed for the manufacturing of a standard 80×120 cm EUREPAL pallet are provided in the Ecoinvent dataset EUR-flat pallet/RER as reported in table
4.16, also with respect to the reference flow of the inventory, on the basis of the value of
6.54×10-5 pallet-units/litre calculated above. The module, which does not account for the
burdens associated with pallet assembling, is therefore employed to model the manufacturing
of this amount of pallet units. As it can be noticed, the total mass of involved materials (24.8
kg) outweighs that of 22 kg usually attributed to standard EUR-EPAL pallets.
189
Table 4.16: Materials employed for pallet manufacturing (Kellenberger et al., 2007)
Total volume Total mass Total mass
(m3/unit)
(kg/unit)
(kg/litre)
Wooden boards
8
0.0335
16.6
1.09×10-3
Glued particle wood blocks
9
0.0117
8
5.23×10-4
Total wood
0.0452
24.6 1.61×10-3
Steel nails
78 (0.0025 kg/nail)
0.195
1.28×10-5
Total
24.8 1.62×10-3
Input materials
Number
To model the manufacturing of 2.54 g of cardboard interlayer, the Ecoinvent dataset
Whitelined chipboard, WLC, at plant/RER is empolyed, according to the same considerations
made above for handle cardboard strip.
As for bundle heat-shrink film, LLDPE stretch-film is assumed to be manufactured through
extrusion of virgin LLDPE granules. Linear low density polyethylene is a copolymer of
ethylene and monomers of another short chain olefin in low concentrations (2.5-3.5%) with a
density of about 915-925 kg/m3, in reason of its high content of very short side branches
(Boustead, 2005b; Hischier, 2007a).
Life cycle data associated with the production of LLDPE virgin granules are provided by the
Ecoinvent dataset Polyethylene, LLDPE, granulate, at plant/RER. According to the same
considerations made for heat-shrink films, the new module LLDPE stretch-film is created to
model the production of 0.321 g of film through extrusion of 0.329 g of LLDPE granules
(Extrusion, plastic film/RER).
Analogously, the module LDPE top-layer film is created to model the production of 0.229 g
of film through extrusion of 0.235 g of LDPE granules.
At the end of their useful life, all transport packaging materials are assumed not to be handled
by the municipal waste management system since they become waste nearby commercial
premises where they are collected by private operators. For this reason their contribution was
not considered for the calculation of the amount of waste to be managed under this scenario
(paragraph 4.5.1).
As consequence the burdens of their end of life treatments have to be considered within this
inventory. In particular all the materials are supposed to be recycled for secondary raw
material production and recycling is modelled through the avoided burden approach
(paragraph 2.2), as will be better described for each single material.
Recycling of pallets wood has been modelled with the approach employed in Rigamonti and
Grosso (2009), assuming that recycled wood is utilised as secondary raw material for the
190
manufacturing of particle board, which in turn is considered to avoid the burdens associated
with the manufacturing of a certain volume of plywood board from virgin raw material. In
particular a substitution rate equal to 1:0.6 is assumed, as suggested by the same authors on
the basis of the smaller mechanical flexion strength of particle board with respect to plywood
board. This means that 1 m3 of particle board can avoid the production of only 0.6 m3 of
plywood board. A conversion rate equal to 1,076 kg of collected wood per m3 of particle
board and a recovery efficiency of 95% of collected wood into the finished product are
considered.
The new module, Wood recycling, is thus built up to account for the burdens associated with
the recycling of 1.61×10-3 kg of pallet wood.
Also pallet steel nails are assumed to be recycled and employed for the production of
secondary steel in electric arc furnaces, allowing to avoid the production of primary steel in
an oxygen converter. A recovery efficiency of 90.5% and a substitution rate equal to 1:1 are
considered. It is indeed actually possible to assume that both primary and secondary steel
have got the same properties (Rigamonti and Grosso, 2009). The module Steel recycling is
created on the basis of life cycle data reported by the same authors, to model the recycling of
1.28×10-5 kg of steel nails.
Cardboard interlayer recycling foresees that they are employed in secondary pulp production
substituting virgin wood pulp and in particular unbleached thermo-mechanical pulp, which
represents the only typology of pulp produced in Italy (Rigamonti and Grosso, 2009). A
substitution rate of 1:0.833 is employed, considering a maximum number of possible turns of
recycling for paper fibres equal to 5, as suggested by the same authors. The recovery
efficiency of the process is assumed to be pair to 89%.
The module Paper recycling is therefore created on the basis of these considerations to
account for the burdens associated with the recycling of 2.54 g of cardboard interlayer.
Finally, LLDPE stretch-film and LDPE top-layer film are assumed to be regranulated and
employed in the manufacturing of profiled bars made from a polyolefines mixture. The
module Profiled bar from POF mix recovery, already described in paragraph 3.3.2, is
employed to model the recycling process of 0.55 (0.321+0.229) g of film.
All the processes associated with the life cycle of transport packaging materials are utilised to
build up in SimaPro the new module Transport packaging materials which accounts for the
respective burdens.
191
Bottling plant operations
As previously described, all the operations required for the production of the complete
transport unit of bottled water take place at the bottling plant: preforms blowing, bottles
filling, capping and labelling, packaging in bundles and palletizing. Other subsidiary
operations are filler machine washing and machineries maintenance.

Energy consumptions
The most energy-consuming phases are bottles blow moulding, which requires compressed air
generation, and bottles bundling into the heat-shrink oven. In particular, only electricity is
required when water has to be bottled within PET containers.
It has not been possible to obtain disaggregated data for each productive stage but only the
total amount of electricity consumed by the bottling plant during the year 2009: 1,423,626
kWh. The company estimates that of this, about 1-2% are associated with services (lighting,
conditioning, offices electronic equipments). Of the remaining amount, about 70% is related
to bottling and packaging operations of the PET line, while 30% to those of the glass line.
Knowing that, of the 80,000,000 litres of water bottled during the year 2009, 48,000,000 litres
were bottled in PET containers, the electricity consumption for bottling plant operations
required to deliver 1 litre of water packaged in PET containers, can be calculated as follow:
Ee PET line 
1,423,626 kWh/y  0.98  0.7
 0.0203 kWh/litre
48,000,000 litres/y
Specific consumption of services has instead to be calculated on the basis of the total volume
of water produced:
Ee services 
1,423,626 kWh/y  0.02
 3.56  10 -4 kWh/litre ,
80,000,000 litres/y
which is minimal. The value that has to be considered in the analysis can now be calculated
by summing up the two results:
Ee LCA_PET  0.0203  3.56  10 4  0.0207 kWh/l
192
The burdens associated with the generation of this amount of electricity (0.207 kWh) are
modelled through the Ecoinvent dataset Electricity, medium voltage, at grid/IT.

Raw materials and natural resources consumptions
Main raw materials and natural resources consumptions are represented by lubricating oil for
machineries ordinary maintenance and by detergents and water employed for daily and
weekly washings of the filler machines. The entity of these consumptions, except for water
one, for the year 2009, are reported in the first column of table 4.17, while the second column
shows the same consumptions with respect to 1 litre of bottled water, calculated by dividing
the first by the total volume of water produced by the company (80,000,000 litres). This
because it has not been possible their disaggregation between PET and glass line. Anyway
this is an acceptable approximation if considering that the washing procedures are the same
for both lines.
Table 4.17: Consumptions of lubricating oil and detergents for bottling plant operations
Materials
Amount – year 2009 (kg) Specific amount (kg/litre)
1251
1.56×10-6
Lubricating oil
Detergent for daily washing:
Alkaline detergent (Enduro Super)
300
3.75×10-6
Acid detergent (Enduro CID)
200
2.5×10-6
Foaming disinfectant (Diverfoam active)
150
1.88×10-6
Detergent for weekly washing:
Caustic detergent (Distar 44)
150
1.88×10-6
2
Not-foaming disinfectant (Divosan forte)
524
6.55×10-6
(1) Calculated as average between the years 2009 and 2008, considering that only in this last 250
kg were disposed of
(2) Calculated considering that this agent is dosed in a measure of 0.03% of the 3,000 litres of
water utilised for preparing the washing solution for the two filler machines, and 52 working
weeks per year. The whole amount (1,700 kg) consumed by the company is indeed utilised also
(and principally) for refillable glass bottles washing and, since it was not possible to separate the
two contributions, the whole consumptions will be totally assigned to this last process, according
to a conservative approach
Manufacturing of 1.56×10-6 kg of lubricating oil is modelled through the Ecoinvent dataset
Lubricating oil, at plant/RER.
An average water consumption of 3,500 l/d is instead estimated by the company for the daily
washing and rinsing of the filler machine or either 7,000 l/d for both lines. Considering then a
total of 250 working days per year and the annual production of 80,000,000 litres, a specific
volume equal to 0.0219 litres/litre can be calculated.
193
With regard to the weekly washing, 1,500 litres of water are instead required for the
preparation of the two washing solutions, while an average consumption of 10,000 l/week for
rinsing is estimated. Considering a total of 52 working weeks per year and that two lines have
to be washed, the whole specific consumption of water can be estimated as:
Vwater 
(1,500  2  10,000)  52  2
 0.0169 litres/lit re
80,000,000
A whole consumption of 0.0219 + 0.0169 = 0.0388 litres/litre of water is therefore ascribed to
the process and is modelled as a natural resource (Water, well, in ground).
In order to carry out the inventories of detergents, the chemical composition specified in the
respective safety data sheets is employed, even if this last could be an incomplete composition
since only hazardous substances are specified. Moreover because of data lacking, it has not
been possible to inventory most of these substances in terms of the exact compound and
therefore a precursor or a compound of the same category is considered. For instance
ethylene-diamine-tetra-acetic acid (EDTA) is assumed to model tetrasodium EDTA or either,
the surfactant potassium alkyl-benzene sulphonate is assumed to be represented by a generic
linear alkyl-benzene sulphonate. However in most cases these simplifications are made for
substances present in the composition with a percentage lower than 5% and furthermore they
could be considered widely acceptable in view of the really modest contribution given by
their production to the impact categories considered in this study.
The composition of each detergent with the respective Ecoinvent dataset employed for its
modelling are reported in tables from C.1 to C.5 of appendix C. The percentage of product not
covered by the substances declared in safety data sheets and required to reach 100% of the
composition is considered to be totally represented by demineralised water (Water, deionised,
at plant/RER), usually employed to complete the solution.

Waterborne emissions
Since no chemical analysis of wastewaters generated at the plant are available, waterborne
emissions associated with the utilisation of detergents during the washing process are
estimated on the basis of their content of COD, nitrogen (N) and phosphorus (P) specified in
the respective technical data sheets. By multiplying these values for the specific consumption
194
of each detergent, calculated in table 4.17, the specific emissions leaving the bottling plant
can be obtained as reported in the first column of table 4.18.
Considering that wastewaters are then collected and treated at a municipal treatment facilities,
the actual value of the emissions to the environment are defined by considering the average
removal efficiencies achievable with a traditional activated sludge biological process, as
reported in Bonomo (2008) and presented in table 4.18, together with the resulting emissions.
Table 4.18: Waterborne emissions associated with filler machines washing, leaving the bottling plant and
released to the environment
Pollutant Input to the WWTP  removing Output from WWTP
(g/lbottled water)
(g/lbottled water)
(%)
COD
1.76×10-3
42.5*
1.01×10-3
-5
N
2.18×10
25
1.63×10-5
P
2.76×10-4
20
2.21×10-4
(*) Calculated considering a 85% removal efficiency for BOD and an
average rate COD/BOD=2 into urban sewage (Bonomo, 2008)
Burdens already associated with the treatment of an unpolluted sewage, which does not
contain bio-solids, can be found in the Ecoinvent dataset Treatment, sewage, unpolluted, to
wastewater treatment, class 3/CH which is therefore chosen to model the treatment of the
0.0388 litres originating from the washing processes.
Cryogenic CO2 is also employed to neutralize the alkalinity of the sewage, but since it was
not possible to quantify the respective consumption, it was not included in the present
inventory.
The new module Filler machines washings is appositely created to account for water
consumptions and waterborne emissions of the washing process as well as the burdens
associated with detergents manufacturing and sewage treatment, by recalling the modules
described above and in appendix C, as better detailed in table 4.19.
195
Table 4.19: Major burdens associated with filler machines washing process and respective modules utilised for
their modelling and to create the module Filler machines washings in SimaPro
Raw materials/natural
resources
Water2
Alkaline detergent (Enduro
Super)
Foaming disinfectant
(Diverfoam active)
Not-foaming disinfectant
(Divosan forte)
COD
Nitrogen (N)
Phosphorus (P)
Other processes
Amount (kg/l)
Module1
0.0388
Water, well, in ground
3.75×10
-6
2.5×10-6
Enduro Super
Enduro CID
1.88×10
-6
Diverfoam active
1.88×10
-6
Distar 44
6.55×10-6
Divosan forte
Module1
Treatment, sewage, unpolluted,
Wastewaters treatment
0.0388
to wastewater treatment, class
3/CH
(1) In Italic the modules taken from Ecoinvent database, the others are build up on
purpose
(2) Modelled as natural resource without assigning any production burdens

Amount (kg/l)
1.01×10-3
1.63×10-5
2.21×10-4
Amount (kg/l)
Waste flows
The only waste treatment process considered in the inventory is that associated with the end
of life of exhausted lubricating oil. According to COUU (2010) the first treatment option in
Italy for exhausted mineral oil is its regeneration for the production of regenerated lubricating
bases (about 65%), and fuel oil (20-25%). In the case in which exhausted oil does not satisfy
technical requirements to allow its regeneration, it is employed for combustion which, in
general, takes place in cement production plants, in substitution of traditionally employed
fossil fuels such as coal or fuel oil. Only in the case in which exhausted oil contains high
concentrations of not easily separable pollutants, to make any possible treatment aimed at
their separation uneconomic and unfeasible, it is sent to thermal destruction (incineration
without energy recovery). This is the case of oils containing high concentration of PCBs (such
as the ones once employed as dielectric material within transformers), or chlorine. Also
combustion in cement production plants is indeed not feasible for these lasts because of the
presence of a flue gas cleaning system inadequate to the nature of the oils to be burned.
Lubricating oil employed at the bottling plant should have characteristics suitable to undergo
the regeneration process, but it has not been possible to model such a process. Data are
instead available about the process of incineration with energy recovery of mineral oil in an
196
hazardous waste incinerator, in the Ecoinvent module Disposal, used mineral oil, 10% water,
to hazardous waste incineration/CH. This last is therefore employed to model the end of life
of 1.56×10-6 kg of exhausted oil. Since Ecoinvent works with no credits, the avoided burdens
associated with the production of thermal energy and electricity have been added. To this end,
an oil lower heating value of 34.7 MJ/kgoil as well as a thermal and an electrical efficiency
equal to 74.4% and 10% respectively, are employed, as specified in the database. Considering
then a self consumption of electricity pair to 1.033 MJ/kgoil (always from the database) and
heat losses of 20% during its distribution and exchanging, a net production of thermal energy
and electricity equal to 20.7 MJ/kgoil and 0.68 kWh/kgoil, can be respectively calculated. The
net produced thermal energy is supposed to avoid the generation of an equivalent amount of
heat from industrial methane boilers at the service of a district heating system, while
generated electricity is supposed to avoid the production of an equivalent amount of energy
from the Italian country mix, as considered for plastic and paper incineration processes
described in paragraphs 3.3.3 and 4.5.1.
The module Lubricating oil-life cycle is finally created to account for the burdens associated
with the manufacturing and the incineration of 1.56×10-6 kg of lubricating oil originated from
maintenance activities at the bottling plant, as better detailed in table 4.20.
Table 4.20: Processes associated with the life cycle of mineral oil and respective Ecoinvent modules utilised to
create the module Lubricating oil-life cycle in SimaPro
Processes
Production of lubricating oil
Incineration of mineral oil
Amount (kg/l)
1.56×10-6
Ecoinvent module
Lubricating oil, at plant/RER
Disposal, used mineral oil, 10% water,
to hazardous waste incineration/CH
Transportations
Transportation of raw materials from the manufacturing site to the bottling plant are neglected
in this study in reason of the high variability of the associated distances, which depend by the
actual location of the bottling plant. Transportation of complete pallets with water to retailers
as well as of bundles with bottles from these lasts to consumers houses are instead considered.
Transport distance of complete pallets is defined by calculating the average distance of the
bottling plants locations of the major Italian mineral water brands from the city of Milan, the
most important urban centre of northern Italy which holds in this region a central position and
for this reason it is considered to be a suitable choice to take into account both short and long
197
distances. Chosen main brands are those belonging to the first eight Italian producer groups
reported in table A.1 of appendix A. An average distance equal to 300 km is resulted on the
basis of the single distances estimated for the single plants with the support of a route planner
and reported in table A.2 of appendix A.
The mass to be transported is that of the whole transport unit which has to be calculated for
each container format. For example, in the case of 1.5 litres bottles, transport unit is
composed by the pallet (24.8 kg), by the three cardboard interlayer (3×0.6 kg), by the stretchfilm (0.245 kg), by the top layer film (0.175 kg), by the 504 bottles comprehensive of cap and
label (504×0.03518 kg), by the contained water (504 x 1.5 kg) and by the bundle heat-shrink
film with handle (84×0.02378 kg). All this results in a total transport unit mass of 802.7 kg.
This value have then to be divided by the total volume of water transported on the pallet (756
litres) and multiplied by the share of 1.5 litres bottles in the packaging mix (86.1%), in order
to calculate the mass to be transported for 1 litre of water packaged in 1.5 litres bottles,
reported to the reference flow:
M transport_ 1,5l 
802.7 kg/pallet 86.1

 0.914 kg/l
756 litres/pallet 100
By repeating the same procedure for the other two typologies of packaging and summing up,
it is possible to obtain the value of the transport mass to be employed. Results of these
calculations are showed in table 4.21.
Table 4.21: Calculation of transported masses in relation to the reference flow
Bottles size Share
(litres)
(%)
2
6.3
1.5
86.1
0.5
7.6
Total transported mass
(kg)
957.4
802.7
819.1
Total transported water Specific transported mass
(kg)
(kg/litre)
912
0.066
756
0.914
756
0.082
Total
1.06
The value to be considered in SimaPro is that obtained by multiplying the transport mass by
the covered distance which is therefore equal to 1.06 kg/litre×300km=318.9 kg×km/litre.
Moreover, also the return trip of empty pallets from retailers to the plant have to be accounted
for. In this case the transport unit is the pallet itself and by repeating therefore the same
198
procedure but considering only pallets mass (24.8 kg), it is possible to calculate a specific
transport mass of 0.0324 kg/litres which corresponds to 9.72 kg×km/litre.
Since transportation from the examined plant to retailers are made with 25 tonnes trucks or 44
tonnes trailer trucks, the Ecoinvent module Transport, lorry >16t, fleet average/RER, is
utilised to model this process.
Transportation of packaged water from retailers to consumers houses by means of a private
car is finally considered. In particular an average roundtrip distance of 10 km is arbitrarily
assumed as a base-case value in the present inventory, also on the basis of the fact that, for
example, Brynjolfsson and Smith (2000) estimate an average roundtrip distance of about 8 km
(5 miles) to be driven by an average U.S. consumer to reach a book or a CD retailer.
Moreover each 6-bottles bundle is arbitrarily considered to be part of a whole purchase of 30
items at the retail store and therefore 1/30 (3.33%) of the roundtrip burdens are allocated to its
transportation. So assigned burdens have in turn to be reported to the actual volume of
transported water which in the case of 1.5 litres bottles is equal to 9 litres. Only this typology
of bottles is considered for simplicity to be transported, in view of their quite exclusive
presence in the considered packaging mix (86.1%).
The Ecoinvent module Transport, passenger car/RER is employed to model the burdens
associated with this transportation phase and is recalled with the actual distance of:
D retailer consumer houe 
10 km 1

 0.037 km/litre
9 litres 30
In view of these several assumptions, variations of the percentage of allocated burdens and
therefore implicitly of the distance to be covered will be however considered during
sensitivity analysis in paragraph 5.3.
The whole inventory of virgin PET bottled water production and delivering is implemented in
SimaPro by creating the module Bottled water, virgin PET, one-way, packaging mix , at
consumer, which recalls all the processes described since now and accounts for all the
upstream burdens associated with the delivering of 1 litre of bottled water to the consumers
through the considered packaging mix.
The whole scenario is instead implemented in the module Baseline scenario 1 (virgin PET
one-way bottled water), which accounts for the treatments of the amounts of waste generated
199
by the annual consumption of 152.1 litres of bottled water, as well as the upstream burdens
associated with their delivering to consumers, by recalling the above mentioned module.
The typology and the magnitude of the major processes which characterize the present
scenario described up to now are summarized in table D.1.
4.6 Baseline scenario 2 (Utilisation of recycled PET one-way bottled water)
The only difference of this scenario with respect to the previous one (baseline scenario 1) is
the fact that preforms are considered to be manufactured with a 50% recycled PET content,
while the amount of waste generated is instead the same.
This choice finds its justification in the possibility given by the recent Decree number 113 of
the Health Ministry, dated 18 May 2010, which allows the use of recycled PET in a content
up to 50% for bottles to be employed for mineral water packaging. Just on the basis of this
possibility the Italian bottling company Levissima has indeed recently introduced in the
market one typology of 1 litre bottles with a 25% recycled PET content.
The goal of considering this option is to evaluate if the use of recycled material can modify
the environmental performances of associated with the use of bottled water with respect to
public network water.
From a LCA perspective, recycling of post consumer bottles for the production of secondary
PET granules to be employed again for bottles manufacturing can be modelled as a case of
closed loop recycling, also referred to as Bottle-to-Bottle (BtB) recycling. The same inherent
technical properties of recycled PET granules are indeed assured by normally succeeding the
traditional re-granulation process a further step aimed at increase their intrinsic viscosity (IV)
and at removing any possible residual organic contamination from the previous use of the
material (Culbert and Christel, 2003). Intrinsic viscosity is a parameter associated with
molecular weight of the polymer and its increase has to be performed since the injection
moulding process requires to deal with a material with an intrinsic viscosity greater than 0.740.75 dl/g (which refers to a molecular weight greater then 24,000 g/mol), while re-extruded
PET granules are characterized by an intrinsic viscosity of between 0.68 and 0.72 dl/g and
therefore by a lower molecular weight (Furiano, 2009; Rieckmann and Völker, 2003).
This reduction of intrinsic viscosity is caused by hydrolysis, thermal and thermal oxidative
degradation during the recycling process. Hydrolysis is fostered by the use of sodium
200
hydroxide during PET flakes washing which can allow the generation of acidic terminal
groups on the polymeric chain promoting therefore hydrolysis reactions. Heating PET
granules above their melting temperature during extrusion involve instead the occurring of
thermal degradation reactions which mainly lead to the generation of acetaldehyde and to the
formation of carboxyl end groups, resulting therefore in a further decrease of their molecular
weight (intrinsic viscosity). In the presence of oxygen, thermo-oxidative degradation takes
place, which is much faster than thermal degradation in an inert atmosphere. Both thermal and
thermo-oxidative degradation can also cause yellowing of the polymer (Furiano, 2008;
Rieckmann and Völker, 2003).
Available options aimed at intrinsic viscosity increase are represented by reactive extrusion,
melt-phase polymerization and solid-state polycondensation (SSP), but in particular this last is
generally employed because, other than increase intrinsic viscosity it also promotes the repolymerization of degradation products, such as acetaldehyde, potentially originating from
any previous heating stages such as extrusion. Reduction of acetaldehyde content during the
SSP process is indeed an aspect of major importance during the production of bottle grade
granules (Culbert and Christel, 2003).
The process substantially consists in heating up PET granules at a temperature lower than
their melting point to allow their partial repolymerization in the solid state through
condensation, which involves molecular weight and intrinsic viscosity increase (Rieckmann
and Völker, 2003). Some more details concerning the SSP process will be given forth in this
paragraph.
On the basis of these considerations it is clear how the PET recycling process, strictly
belonging to the sole waste management system in the previous scenario, in this case also
provides raw materials for the upstream product system associated with recycled PET bottled
water delivering, making the two systems partially integrated. Both upstream and downstream
processes dealing with PET bottles are therefore subject to the mass flows showed in figure
4.2, calculated through mass balance and by considering that half of the whole PET bottles
amount annually consumed (3.42/2=1.71 kg/year or 22.5/2=11.25 g/litre) is manufactured
with recycled granules.
201
SSP2 of recovered PET granules
1.72 kg/year (11.3 g/litre)
Recovered
PET granules
1.72 kg/year
(11.3 g/litre)
Preforms manufacturing - =99.4%
Selection and recovery of
PET bottles for
BtB1recycling (=80%)
Scraps
0.43 kg/y
2.8 g/litre
Virgin PET granules manufacturing
Bottles manufacturing
Use and waste generation
Separ. coll.
=77%
Collected PET bottles
2.63 kg/year
(17.3 g/litre)
Selection and recovery of
PET bottles for
other applications (=80%)
(1) BtB=Bottle to Bottle
(2) SSP=Solid-state polycondensation
0.79 kg/year
(5.2 g/litre)
PET bottles incineration
Scraps
0.09 kg/y
0.64 g/litre
Recovered
PET granules
0.39 kg/year
(2.6g/litre)
Virgin PET granules
avoided production
Figure 4.2: Mass flows involving PET bottles in baseline scenario 2
On the basis of mass flows showed in figure 4.2, the following adjustments are made in the
modelling of the scenario in SimaPro:

in the waste management system, only the recycling process of 0.48 kg of PET bottles are
considered to avoid virgin production of PET granules in an amount which, according to
the 80% recovery efficiency and the substitution factor of 1:0.81 (paragraph 3.3.2),
corresponds to 0.31kg. The remaining 2.15 kg of PET bottles are instead considered to be
recycled without avoiding any virgin production burdens but,

in the module associated with preforms production (R-PET preforms-closed loop), only
22.5/2/0.994=11.3 g of PET granules are considered to be manufactured from virgin raw
materials, instead of the whole amount of 22.5 g. The burdens associated with the solidstate polycondensation process of 11.3 g of recycled PET granules are however included
in this module by recalling the module Solid state polycondensation which will be now
described.
202
Different variants of solid-state polycondensation exist according to the fact that a continuous
or a batch system is employed or that flakes extrusion in granules is carried out before or after
the process. However SSP of granules is generally preferred when dealing with recycled
material for a series of reasons, such as the fact that extruded granules have an uniform
thickness which allows an as much homogeneous increase of intrinsic viscosity, thing that
does not happen when using flakes. Again, melting of flakes for extrusion involves possible
generation of degradation products such as acetaldehyde which would have indeed been
removed if a subsequent SSP process had been carried out (Culbert and Christel, 2003).
For the description of a typical SSP process we refer to the viscoSTAR technology developed
by the company Starlinger, for which also energy consumptions data are available (Starlinger,
2010a; 2010b; 2010c). The viscoSTAR process is a SSP process aimed at intrinsic viscosity
increase and decontamination of both polyester granules or flakes in which they are firstly
heated at about 160°C to achieve their crystallization, in order to avoid formation of lumps in
the subsequent manufacturing processes: after extrusion granules are indeed partially
amorphous. They are then fed into a pre-heater to reach the reaction temperature, which is
lower than the melting point (245-255 °C) and generally of between 220 and 235 °C. So
heated material is hence transferred to the reactor where the solid-state polymerization takes
place and water and glycol are released. The residence time depends by the initial and the
final value of intrinsic viscosity to be reached. Vacuum conditions are maintained in the
reactor in order to facilitate volatilization of contaminants, either those originating from the
SSP process itself, or those associated with the original use of the material, in order to make it
suitable for direct food contact. After the reaction time granules are cooled and transferred to
a storage silo. Alternatively they can be cooled to a lower extent and directly sent to the
desired manufacturing process such as injection moulding or extrusion, involving energy
savings for the avoided necessity of an additional drying stage, usually required. Further
savings from the possible previous re-granulation step (extrusion) can also occur if granules
are only partially cooled and then directly introduced into the SSP system (Culbert and
Christel, 2003).
According to Starlinger (2010b) energy consumptions (only electricity) associated with this
technology depend by the features of the material to be processed, in particular by its level of
contamination, its initial intrinsic viscosity and if it is in form of flakes or granules. A range
of consumptions of between 120 and 250 kWh per tonne of output flakes/granules is therefore
provided. Even if it is not specified, it is probable that a (catalytic) combustion stage is
203
performed to oxidise reaction products as well as volatilized contaminants as it is done for the
Buhler SSP process (Culbert and Christel, 2003).
According to a conservative approach a value of 250 kWh/t is assumed for the present study
to represent electricity consumptions. No information are available concerning possible
airborne emissions, but they can be considered to be of secondary entity in view of they
efficient removal during the combustion stage.
On the basis of these considerations the module Solid-state polycondensation is therefore
created in SimaPro to account for the burdens associated with the processing of 1 tonne of
PET flakes or granules through polycondensation.
The inventory modelling virgin PET bottled water supplying is therefore adjusted according
to the considerations made up to now, to model the delivering of 1 litre of water through 50%
recycled PET one-way bottles (Bottled water, R-PET, one-way, packaging mix, at consumerclosed loop). The whole scenario is instead implemented in the module Baseline scenario 2
(R-PET one-way bottled water-closed loop).
If one would like to maintain unlinked the process of bottles recycling, which belongs to the
waste management system, from the process of bottles manufacturing which represents an
upstream component of the bottled water product system, continuing to employ the avoided
burden approach to deal with the whole amount of material sent to recycling, an open loop
recycling procedure could be theoretically applied to model the present scenario. In this case
recycled PET is not assumed to be provided by the system under investigation but from
external product systems. A modelling variant of this scenario will be therefore proposed
according to these considerations, but some general remarks concerning the most important
issues associated with open-loop recycling have to be done before.
The utilisation of recycled material, originated from an unknown product, for the
manufacturing of a new product, in our case bottles, and its further recycling into another
undefined product, is referred to as open-loop recycling within the framework of life cycle
assessment. When open-loop recycling occurs, the necessity to deal with the problem of how
to allocate burdens associated with virgin production, recycling and final waste management
of the recycled material, among the various product life cycles in which it is employed arises.
Burdens from these processes are indicated respectively as V1, R1, R2 and W3 in figure 4.3
(Ekvall and Tillman, 1997), where the system under investigation in this study corresponds to
the product life cycle number 2.
204
Primary material
production (V1)
Production of
product P1
Recycling
process (R1)
Use of
product P1
Production of
product P2
Recycling
process (R2)
Use of
product P2
Production of
product P3
Use of
product P3
Waste
management
(W3)
Product life
cycle
1
Product life
cycle
2
Product life
cycle
3
Figure 4.3: Product systems involved by the same material flow in the case of open-loop recycling (Ekvall and
Tillman,1997)
Concerning the issue of how to perform allocation scientific consensus is not reached at
present, but it is in general recognized how allocation procedures should be chosen as a
function of the study objective, in particular if it is intended or not for decision support
(Ekvall and Tillman, 1997).
According to the same authors, the simplest way to perform allocation is the cut-off approach,
which foresees that only the environmental burdens directly generated by a given product
system are assigned to it. As consequence, indicating as L1, L2 and L3 the burdens of the
three product systems of figure 4.3, they would be defined as follow:
L1 = V1,
L2 = R1,
L3 = R2 + W3.
meaning that to the system investigated (P2) are only assigned the burdens associated with the
recycling of the material generated as waste in the first product life cycle (P1), to which are
instead allocated all virgin production burdens. Environmental burdens of further recycling
and final disposal are shifted to the last product life cycle (P3).
205
This method is just applied as a modelling variant of this scenario and therefore the burdens
associated with selection and recovery of unspecified postconsumer bottles and containers
waste are assigned to the share of recycled PET granules employed in bottles manufacturing.
Contrarily to the original methodology mentioned above, the recycling of bottles of the
system under investigation is however considered to be a process belonging to the waste
management system, and is modelled as in baseline scenario 1 by utilising the avoided burden
approach.
This last choice could be justified by considering that, being this study an hybrid of waste
management and product oriented LCA, also an hybrid allocation procedure is applied: the
cut-off approach for the upstream product system and the avoided burden approach for the
waste management system.
On the basis of these considerations, the modules associated with plastic selection and PET
recovery are substituted to the one associated with virgin PET granules manufacturing into
the preforms production module (R-PET preforms - open loop). In particular
22.5/2/0.994=11.3 g of PET granules are considered to be obtained from recycling and the
remaining 11.3 g from virgin production. This means that 11.3/0.8=14.1 g of post consumer
bottles have to be selected. Moreover the solid-state polycondensation process of 11.3 g of
recycled PET granules is finally included (Solid-state polycondensation).
So modified bottled water inventory is implemented in the module Bottled water, R-PET,
one-way, packaging mix, at consumer-open loop, while the whole scenario is instead
implemented by creating the new module Baseline scenario 2 (R-PET one-way bottled wateropen loop).
The comparison of the results obtained with the two different described approaches will be
showed in paragraph 5.1.
As for baseline scenario 1 figure D.2 schematically depicts the most important processes
which characterize this scenario when modelled through the closed loop approach,
highlighting in particular those processes which differ from the previous virgin PET one-way
bottled water scenario. Table D.2 summarises instead the magnitude through which these
different processes are included.
206
4.7 Baseline scenario 3 (Utilisation of PLA one-way bottled water)
In this case, the differences with respect to the virgin PET scenario (baseline scenario 1)
concern the material employed for preforms production which is assumed to be polylactic
acid (PLA). This material is in particular being utilised by the Italian bottling company Fonti
di Vinadio for small scale production of bottled water and its pilot experience will be taken as
reference for the development of this scenario. The mentioned company employs PLA
granules produced by the world largest manufacturing plant sited in Nebraska and belonging
to the company NatureWorks. At present only bottles and labels are produced out of this
material but soon it will be possible also PLA heat-shrink films production (Parola, 2010). In
spite of this, we have decided to consider the utilisation of PLA only for bottles
manufacturing in order to allow a fair evaluation of the effects involved by the changing of
the sole material employed for bottles manufacturing.
4.7.1 Generalities on polylactic acid (PLA)
Polylactic acid is a biodegradable polymer of natural origin which can be obtained from the
fermentation of any abundant source of sugar (dextrose) such as maize, wheat, sugar beets
and sugar cane. The productive process at NatureWorks employs maize starch as dextrose
source, which nowadays is the most economical and abundant source, and can be summarised
in the following stages. Maize is first grown, harvested and transported to the plant. Here its
kernels are separated from the others plant parts to be cooked at 50°C for 30-40 hours,
involving their swelling and softening and making in this way them suitable to the following
stages of grinding and screening which have the purpose to isolate the starch from the hull.
Starch is then hydrolyzed into its monomer, dextrose, which through a biologic fermentation
process is converted into lactic acid. Lactic acid molecules links together to form rings called
lactide dimers which are then purified and polymerized by inducing their opening and linking
together to form a long chain of polylactic acid (NatureWorks, 2010a).
Bottles are demonstrated to be completely compostable packaging materials by AMIAT
which has carried out a biodegradability test according to the requirements specified in the
207
standards UNI EN 13432:02 and UNI EN 14045:2003 (AMIAT, 2008). For this reason a first
subscenario assumes that their end of life takes place through 100% composting within the
waste management system. A further subscenario in which composting is substituted by
100% incineration is also considered in order to evaluate possible different performances
between the two end of life options. Heat-shrink films, caps and labels are instead considered
to be managed identically to the previous one-way bottled water scenarios, according to the
above explained reasons.
Figure 4.4 schematically shows waste flows in the waste management system calculated
through mass balances of collection and recovery stages. In such balances, packaging
materials unit masses are assumed to be identical to those employed in previous scenarios and
therefore also the amount of waste generated is the same. This assumption is justified by
considering that 0.5 litres and 1.5 litres PLA bottles employed by Fonti di Vinadio have a
mass of 30 g and 15 g respectively, as indicated by the company itself. Since these values are
very similar to those employed up to now (about 33 g and 18 g) they are therefore utilised
also for the present case.
Composting
(or incineration)
3.42 kg
=100%
PLA bottles
3.42 kg
HDPE caps*
0.245 kg
Input
waste
4.1 kg
LDPE heatshrink films
0.378 kg
Separately
collected
material
=33%
=60%
0.125 kg
Paper labels*
0.0615 kg
0.0749 kg
Scraps
0.05 kg
0.498 kg
Paper incineration
0.0615 kg
Recovered
material
Wooden planks
avoided
production
(0.0749 m3)
0.548 kg
(*) Even if in the case of composting caps and labels would be separately collected with
bottles and be part of the scraps originating from the same process, they are assumed for
simplicity to be directly routed to incineration as in the other one-way bottled water
scenarios.
Figure 4.4: Waste flows within the management system for the two subscenarios of baseline scenario 3
208
The processes that have to be considered in the waste management system are therefore the
followings:

composting (or incineration) of separately collected bottles (3.42 kg),

selection of separately collected heat-shrink films (0.125 kg),

recovery of selected heath-shrink films (0.125 kg),

incineration of caps and of not separately collected heat-shrink films (0.498 kg),

incineration of labels (0.0615 kg),

Modelling of PLA bottles composting
The composting process is modelled by means of the data provided in Punzi (2009) and
relative to the Italian plant of San Damiano d’Asti.
The process foresees a first screening stage in which metals and other extraneous fractions are
separated and the material is homogenized through addition of water and by mixing moist
organic waste with coarser green waste material to optimise moisture and porosity. The
mixture then undergoes to a 25-28 day long stage of intense decomposition supported by the
blowing of an air stream through the piles, and to a further stage of slow maturation without
air blowing for around 55 days. A final sieving and air screening stage is employed to
separate coarser wooden residues, which are sent back to the first stage, and plastic and inert
waste which are landfilled. The intense decomposition stage involves the production of
leachate, which is collected and sent to a wastewater treatment plant, and of airborne
emissions, also collected and passed through a bio-filter (Blengini, 2008).
Compost is produced with an efficiency of 0.441 t/torganic waste as highlighted in the mass and
energy balance of the process, reported in table 4.22. Table 4.23 instead presents the airborne
emissions attributed to the process.
209
Table 4.22: Mass and energy balances of the composting process nearby San Damiano D’asti plant (Adaptation
from Punzi (2009))
Input
Amount
Organic waste (t/tow)
1
Water (litres/tow)
89
Electricity (MJ/ tow)
219
Diesel (litres/tow)
2.06
Output
Mature compost (t/tow)
0.441
Airborne emissions (t/tow)
0.59
Metal scraps to recycling (t/tow)
1.12
Leachate to treatment (t/tow)
0.296
Residues to landfill (t/tow)
0.165
(20% putrescible)
Table 4.23: Airborne emissions attributed to the composting process (Adaptation from Punzi (2009))
Pollutant
CO2, biogenic
kg/tow
192
g/tow
CO
19.2
SOx (as SO2)
0.11
NM-VOC
50
NH3
17
N2O
11
HCl
2
Mercaptans
0.18
H2S
0.26
Particulates (< 10 um)
3
mg/tow
HF
200
H2SO4
460
Benzene
200
Cd
5
Hg
7.76
Pb
125
Mn
5
Ni
1.12
Cu
5
Zn
75
ng/tow
Dioxins
3
PAH
20
Produced compost is assumed to be employed with the percentage showed in table 4.24 for
flowers cultivation (substituting peat), in agriculture (substituting mineral fertilizers) and for
landscape applications, without substituting any product. The amounts of products substituted
210
per tonne of organic waste treated, calculated by considering the substitution factors provided
in Grosso et al. (2009), are reported in the third column of the table.
Table 4.24: Products substituted by the application of compost (Adaptation from Punzi (2009))
Field of
utilization
of compost
Flowers
cultivation
%
of
utilization
t compost applied/t
organic waste treated
Substituted
product
kg substituted/
kg substituted/
t organic waste
t compost applied
treated
34%
0.150
Peat
441.2
66.15
Agriculture
62%
0.273
Nitrogen
Phosphorus
Potassium
6.2
2
4.5
1.7
0.55
1.23
Landscape
application
4%
0.0176
-
-
-
Data derived from mass and energy balances, airborne emissions as well as data concerning
the amounts of substituted products, are employed to model the process of composting in a
life cycle perspective, by creating the new module Composting in the software.
Two different approaches are then proposed to model PLA composting. In first instance PLA
is considered to behave as any other organic waste fraction and therefore all process specific
burdens mentioned above are directly utilised to model the composting process of 3.42 kg of
PLA bottles independently from any elemental composition of the treated material.
A second method is also proposed and applied on the basis of the results of the experiments of
Viswas et al. (2001). In particular the authors found that after four weeks of laboratory
composting of pre-composted yard waste together with 30% by weight of extruded PLA
sheets pH dropped from 6 to 4 while no pH variations resulted for a 10% compost-PLA
mixture. Dropping of pH was associated to a likely suppression of the microbial activity since
no overall CO2 emissions difference were registered in exhaust gases from the two systems.
The amount of CO2 generated was however greater than those registered for a 0% mixture,
indicating that degradation actually took place. The authors conclude that PLA can be
efficiently composted when added in amount lower than 30% to pre-composted yard waste.
In this second approach we have therefore considered PLA as a material which needs that
other organic waste fractions contribute to create those suitable conditions for its degradation.
In particular a maximum ratio PLA-compost of 0.3:1 is considered according to the above
mentioned experience, despite different conclusion could be drawn if PLA was added to more
putrescible organic waste, like it is probable to happen in real composting conditions. This
ratio seems however to be reasonable and optimistic if considering that AMIAT (2008),
211
during its biodegradability test, has employed a mixture of PLA with organic waste from
separated collection in a percentage only up to 2.5%.
Therefore composting of 1 tonne of PLA firstly takes the burdens associated with the
composting process of (1/0.3-1)=2.33 tonnes of traditional organic waste, modelled as
described above in this paragraph. Moreover, process specific burdens associated with
consumption of water, electricity and diesel are considered to be the same as traditional
composting process (table 4.22). Airborne emissions of CO2 are instead calculated on the
basis of PLA elementary composition of table 4.25 provided by NatureWorks (2010b), and
reasonably assuming a complete decomposition of the material to CO2 and water. This last, by
leaching through the compost pile becomes polluted and it is assumed to contribute to the
amount of sewage that have to be treated at the wastewaters treatment plant. The respective
amount is always calculated on the basis of the hydrogen content of PLA, even if a so defined
value could be overestimated since part of the water could potentially vaporize.
No emissions of NO2 or SO2 are associated to the nitrogen and sulphur content of PLA since
they are of minimal entity (0.04%).
Table 4.25: Elemental composition and lower heating value of PLA (NatureWorks, 2010b)
Element
C
Cl
H
O
N
S
% (NatureWorks) % (Scaled)
50.05
49.5
0
0
5.7
5.6
45.07
44.5
0.04
0.04
0.3
0.3
101.17
100
Lower heating value (LHV)
19,464 kJ/kg (8,368 Btu/lb)*
(*) 1 Btu = 1.0551 kJ; 1 lb = 0.454 kg
No methane generation is finally taken into account, considering that aerobic conditions are
well assured within the compost pile. It is however important to notice that if this would
happen, a meaningful contribution to global warming would be given, on the contrary of CO2
emissions which are of biogenic nature. Table 4.26 reports the results of these calculations as
well as the process specific burdens attributed to PLA composting.
On the basis of the previous consideration concerning the complete decomposition of PLA, no
avoided production of peat or fertilizers is credited to the composting process. The module
PLA composting is finally created in the software to model the composting process of 1 tonne
of PLA.
212
The comparison of the results obtained with the two different proposed approaches will be
showed in paragraph 5.1.
Table 4.26: Process specific burdens attributed to PLA composting and calculated CO2 emissions and leachate
production
Inputs
Unit
Amount
t/tPLA
Composting of traditional organic waste
2.33
litres/tPLA
Water (process specific)
89
MJ/tPLA
Electricity (process specific)
219
litres/tPLA
Diesel (process specific)
2.06
Outputs/Emissions
kg/tPLA
Leachate to treatment
504
kg/t
CO2 emissions (biogenic)
1,815
PLA
Modelling of PLA bottles incineration
Incineration of PLA is modelled with the same methodology and assumptions already
described for plastic and paper incineration in paragraphs 3.3.3 and 4.5.1 respectively. The
elementary composition of PLA employed for the modelling as well as PLA lower heating
value are those showed in table 4.25. The content of ashes is not reported but it can be
deduced by the provided datum on production of residues (0.01 mg/g), value which is directly
employed to model generation of bottom ashes from the incineration process. Also biogenic
carbon dioxide emissions (2,020 mg/g) are directly provided and utilised in the modelling.
The value is instead coherent with the one calculable on the basis of the carbon content of
PLA (1,815 mg/g).
Reagents consumptions, production of residues and the amount of electricity and heat
generated, are summarised in table 4.27, while airborne emissions are reported in table B.1 of
appendix B together with those of paper incineration.
213
Table 4.27: Summary of waste specific material and energy inputs and outputs of the PLA incineration process
Amount
(g/kgWW)
9.3
Flue gas volume (m3n dry gas/kgWW) @ 11% O2
Reagents consumption:
19.5
Activated carbon
3.7
Urea CO(NH2)2
1.7
Bottom ashes generation
0.0125
of which:
Over-sift to inert material landfill 0.00163
0.0109
0.0112
Fly ashes generation
27.9
36.1
Air pollution control residues generation
20.8
Energy:
Electricity for bottom ashes sorting (kWh/kgWW) 5×10-8
Electricity production (avoided) (kWh/kgWW)
1.31
Heat production (avoided)1 (kWh/kgWW) 0.0024
(1) Distribution and heat exchanging losses included (20%)
Material and energy flows
The module, PLA incineration, appositely created, accounts for all the burdens associated
with the PLA incineration process.
4.7.3 Life cycle inventory of PLA one-way bottled water
Inventory data concerning PLA manufacturing are available from the Eocoinvent database in
which two different modules are in particular established on the basis of the eco-profile of the
NatureWorks process, published in Vink et al. (2007). The first module accounts for the fact
that the company, since 2006, has purchased renewable energy certificates (REC) which
ensure the production of renewable electricity from wind in an amount equivalent to the one
of non renewable energy used for PLA production at the plant. This aspect was translated in
the dataset by modelling energy consumptions through the burdens associated with wind
energy generation, and by contemporarily reducing the amount of CO2, CO, NOx, SOx and
Hydrocarbons emissions originally reported by Vink et al. (2007). Since this module is, in
principle, valid only for the NatureWorks reality, a second dataset is established in Ecoinvent
which instead models energy consumptions through the European electricity mix (Althaus et
al., 2007).
This last module (Polylactide, granulate, at plant/GLO) was therefore employed for the
present study to model PLA manufacturing, in order to assure it a general validity. In
214
particular it was substituted to the module associated with virgin PET granules manufacturing
into the preforms production module originally created for baseline scenario1.
During its pilot experience, the company Fonti di Vinadio has also recognized that a potential
reduction of energetic consumptions, either in preforms manufacturing or during bottling
plant operations, could occur when PLA is used as packaging material. In particular, with
regard to preforms injection it was observed that:

drying of granules can be made with air heated at only 80 °C instead of at 185 °C as
required for PET ones, being the same the drying time (6 hours);

their melting temperature can be reduced from 285 °C to 210 °C and

preforms cooling can be carried out with water at environmental temperature (25 °C)
instead of at 8° C.
As far as bottling plant operations are concerned, the following adjustments have instead to be
performed to the operational parameters of the line:

preforms can be heated by keeping a oven temperature of about 80°C against the 107-110
°C needed for those made of PET;

preforms pre-blowing can be made by insufflating compressed air at 6 bar instead of 11
bar while the final blowing with air at 23 bar instead of 32 bar;

temperature of moulds cooling liquid can be increased to 18 °C from the original 16 °C;

temperature of the label glue basin can be reduced from 145 °C to 135 °C as well as

heat-shrink oven temperature can be lowered from 210 °C to 190°C.
Official data concerning achievable savings in terms of electricity consumptions in
consequence of these operational cunnings are not available. We have however tried to carry
out a rough estimate of these savings on the basis of the technical features of the machinery
employed in the examined bottling company. Regarding potential savings associated with
preforms injection, no enough information were instead available to allow such an estimate.
First of all, as far as preforms heating is concerned, an estimate of these savings can be made
considering that it is performed through 13 batteries constituted by 8 IR lamps of 2 kW and
by 1 lamp of 3 kW for a total installed power of 247 kW. Assuming that they absorb their
maximum power when the heating temperature is 110°C and a linear relation between
215
temperature and absorbed power, the power absorbed when heating is made at only 80°C can
be estimated as:
P80C  247 kW 
80 C
 179.6 kW
110 C
Then considering that the blow moulder machine has a maximum productivity of 22,400
bottles per hour and assuming, for simplicity, a volume of 1.5 litres per bottle, the specific
saving can be calculated as:
S heating 
(247 - 179.6) kW
 0.002 kWh/litre
22,400 bottles/hour  1.5 litre/bottle
An estimate of savings achievable during the blowing process can be instead carried out by
initially considering that compressed air is provided by two compressors with an air flow rate
of 190 m3n/h each one, and that the specific compression work is defined as:

p
k
Wc    vdp 
pV 1   out
k  1   p in
Vin

Vout



k 1
k


  k RT 1   p out
 k  1   pin





k 1
k

,


where:
J
J
 371.16 3 ;
mol K
mn K
-
R = universal gas constant = 8.314
-
kair = cp/cv = 1.4;
-
T = temperature of the input air to the compressor;
-
pin = pressure of the input air to the compressor;
-
pout = pressure of the output air from the compressor:
Being the gas constant expressed as m3n, the temperature of the input air to consider is equal
to 273 K, while its pressure is the atmospheric one (101,325 Pa). Therefore, the specific work
required to reach the pressure of 11 bar needed during PET preforms pre-blowing is equal to:
216
1.4 1


1.4
1.4
J
11
bar



  348,968 J .
Wc  
 371.16 3  273 K  1  

  1 bar 

1.4  1
mn
m 3n


In order to calculate the power required by the compressor, it is now sufficient to multiply this
result by the air flow rate to be compressed (Qi) which, in full load conditions, is equal to the
maximum flow rate deliverable by the two compressors, 390 m3 n /h or either 0.108 m3n /s.
Pc  Wc  Q i  348,968
J
 0.108 m 3n /s  37,689 W  37.7 kW ,
3
mn
Repeating the same calculation considering the output air pressure of 6 bar, required for PLA
preforms pre-blowing, a specific work equal to 237,083 J/m3 n and a required power of about
25.6 kW are obtained. Specific saving can be therefore calculated as:
S pre -blowing 
(37.7  25.6) kWh
 0.00036 kWh/litre.
22,400 bottles/h 1.5
By applying the same procedure for the final blowing stage, the passage from a pressure of 32
bar to 23 bar reduces the power requirement from 64.8 kW to 55.5 kW which results in a
specific saving of 0.00028 kWh/litre. The total saving of the blow moulding process can be
therefore estimated to be equal to:
S blow -moulding  (0.00036  0.00028)  0.00064 kWh/litre .
Finally, as done for preforms heating, savings associated with the lower temperature in the
heat-shrink oven can be estimated by considering that its full conditions power absorption (85
kW) occurs when the temperature of 210 °C has to be reached. This means that in order to
heat air at 190°C, only 76.9 kW are absorbed. Considering finally, that the maximum oven
217
productivity is of 6,000 bundles per hour and, always for simplicity, a 6×1.5-bottles bundle,
the specific saving can be calculated as:
Soven 
(85 - 76.9) kW
6,000 bundles/ho ur  9 litres/bun dle
The saving expected for the whole bottling process (Stot) can now be estimated by summing
up the values found for the three single stages and results equal to 0.0028 kWh/litre.
The amount of energy required for bottling plant operations decreases finally to the value of:
Ee LCA_PLA  Ee LCA_PET - S tot  0.0207  0.0028  0.0179 kWh/litre .
This value has been modified within the bottled water production inventory module (Bottled
water, PLA, one-way, packaging mix, at consumer), while the two subscenarios are
implemented respectively in the modules Baseline scenario 3 (PLA bottled water-composting)
and Baseline scenario 3 (PLA bottled water-incineration).
The most important processes which characterize this scenario are represented in figure D.3
that also highlights those processes which differ from the virgin PET one-way bottled water
scenario. Table D.3 summarises instead the magnitude through which these different
processes are included.
4.8 Waste prevention scenario 1A (Utilisation of public network water:
groundwater from the tap)
This first preventive scenario foresees that the volume of water consumed in form of bottled
water in the previous baseline scenarios, is consumed from the tap. In particular, the
supplying system of the Municipality of Milan, which is characterized by the utilisation of
groundwater only, is firstly considered as a real case study of reference.
Waste generation is limited to the reusable glass jug that will be assumed to be utilised to
conserve water nearby consumers house and to the annually substituted activated carbon filter
218
cartridge of the depuration device that will be considered to be employed to improve water
quality at domestic level. Their contribution is however expected to be of minimal entity and
their handling is excluded for simplicity by the waste management system, but is directly
accounted for in the inventory relative to tap water supplying.
Moreover, the most important upstream life cycle processes involved in tap water supplying
have to be included in the analysis because their magnitude is subject to change among the
investigated scenarios. A detailed inventory of this product system is therefore carried out in
the following paragraph.
4.8.1 Life cycle inventory of public network water: groundwater from the tap
System description
The drinking water collecting, purification and distribution system of the municipality of
Milan is managed by the company Metropolitana Milanese, as the whole integrated water
service of the same city. Other than Milan, the aqueduct serves also the surrounding
municipalities of Corsico and Linate and some users of the municipalities of Buccinasco,
Peschiera Borromeo and San Donato Milanese. The total number of users served during the
year 2009 was of 49,920, of which about 75% represented by domestic users and little
commercial premises and the remaining by agro-zootechnical and industrial users.
The peculiarity of this system consists in the fact that the unique water supplying source is
represented by the underground aquifer.
Groundwater is collected thanks to a network of 548 wells that feed 29 treatment and
pumping stations. Purification treatments have indeed to be carried out for 24 of the 29
stations, since the quality of withdrawn water does not satisfy legal requirements established
for water intended for human consumption. In particular, main pollution problems are
associated with the presence of organ-halogenated solvents such as trichloroethylene and
tetrachloroethylene, among the wide spread ones, as well as pesticides such as atrazine and
2,6-dichlorobenzamide.
The 29 stations foresee specific treatments as a function of the typologies and concentrations
of pollutants that have to be removed from the collected water. Table 4.28 presents the
treatments which take place at the various stations while figure 4.5 shows a representation of
a typical treatment station.
219
2
3
1
1.
Pumping well
2.
Aeration tower
3.
Activated carbon filter
4.
Water reservoir
5.
Pushing pumps
4
5
Figure 4.5: Illustration of at typical scheme of treatment station at the service of the aqueduct of Milan
(Provided by Metropolitana Milanese)
220
Table 4.28: Main features and typologies of treatments carried out at the various treatment stations at the
service of the aqueduct of Milan
STATION
NUMBER
STATION
NAME
TYPOLOGY OF
TREATMENT
Activated carbon basin
Aeration tower
Aeration tower
Aeration tower + CO2
N° TREATMENT
UNITS
4
5
6
4
1
Vialba
2
Novara
3
Comasina
Activated carbon filters
Aeration tower
Aeration tower
Aeration tower + CO2
4
6
18
4
8
6
4
Cimabue
5
Chiusabella
6
Suzzani
Padova
4
4
7
8
Salemi
4
9
Gorla
10
11
12
13
14
15
16
17
18
19
20
20
21
22
23
24
25
26
27
28
29
Armi
Tonezza
Feltre
San Siro
Parco
Linate
Italia
Abbiategrasso
Anfossi
Martini
Ovidio I
Ovidio II
Bicocca
Crescenzago
Cantore
Crema
Assiano
Baggio
Beatice D'Este
Lambro
Corsico
10
Reverse osmosis plant
5
14
9
17
24
16
11
16
18
7
10
11
11
4
20
21
7
Station without treatments
"
"
"
"
Total activated carbon filters
Total activated carbon basins
Total aeration towers
Disinfection
Hypochlorite
"
"
CAPACITY
(l/s)
600
500
600
400
120
600
450
400
200
600
"
"
"
"
600
600
UV-C
600
Hypochlorite
"
"
UV-C
Hypochlorite
"
"
"
"
"
"
"
"
"
"
"
"
"
"
"
"
256
16
31
250
150
300
225
425
600
400
275
400
540
175
250
275
275
100
500
315
6,075
2,400
3,100
As can be seen, the more widely employed treatment is adsorption on granulated active
carbon (GAC) filters, in particular 256 filters for a capacity of 6,075 l/s are installed.
Granulated activated carbon is a material with high porosity and a very high specific surface
(750-1,500 m2/g) which can efficiently remove big organic molecules such as organ-
221
halogenated compounds and pesticides as well as other substances which can alter the
organoleptic quality of water, by retaining them within its porosities when crossed by the
water flow. As a function of the characteristics of the treated water, activated carbon has to be
removed every 12-18 months and reactivated to restore its adsorptions capacities. The
company also estimates that the total volume of activated carbon of a station is renewed every
10 years. Moreover the filtering bed is monthly backwashed to remove possible sand particles
accumulated in the filter which could involve the occlusion of porosities, drastically reducing
purification efficiency. Also 16 basins are employed for this typology of treatment with a
capacity up to 2,400 l/s.
Another important treatment is pollutants stripping in aeration towers, especially for volatile
organic compounds (VOC) removal. In this case water flows through apposite towers against
a powerful air flow which involves volatile pollutants to be transferred from the aqueous to
the aeriform phase. In particular 31 towers for a whole capacity of 3,100 l/s are placed at the
service of the network. In the stations Comasina and Suzzani, which deal with waters of
particular hardness, a flow of cryogenic CO2 is also injected into the treated water to restore
pH at neutral values. The stripping treatment involves indeed volatilization of dissolved CO2
and carbonates precipitation and therefore the outcoming water would be of alkaline and
scaling nature if its pH was not adjusted.
Five lines of reverse osmosis are also installed at the Gorla station, each one with 60
membranes and a whole treatment capacity of 150 l/s, to deal with the presence of nitrates and
chromium (VI). The process consists in pumping water through a semi-permeable membrane
which can retain molecules of ionic dimension, producing a demineralised water. For this
reason only 45% of the total volume undergoes to this treatment and it is afterwards mixed
with non filtered water. All the volume is instead passed over the 10 activated carbon filters
installed at the station.
In all pumping stations, even in those which deal with water that does not require particular
treatments, a disinfection stage is however carried out to remove possible microbiological
contaminations which could take place during the various treatment stages as well as to assure
protection of water quality during its transportation and permanence into the network. This
process is carried out in the reservoirs of which each pumping station is equipped. Besides as
compensation basins, they are indeed also employed as disinfection basins. The disinfecting
agent utilised is a solution of sodium hypochlorite at 14% m/v of active chlorine which is
dosed in a quantity of 0.15-0.2 mg/l (as pure hypochlorite) in order to ensure an output
222
concentration of residue chlorine of about 0.05 mg/l. This value is four times lower than the
value suggested by the legislation and assures network persistence without altering the
original organoleptic characteristics of water. Two exceptions are represented by the stations
of Salemi and Feltre, where disinfection is carried out by means of UV lamps with powerful
bactericidal action.
As anticipated the treated water is stored in reservoirs, one for each station, where by means
of powerful centrifugal electric pumps it is introduced into the network. Reservoirs indeed
allow to store water during the hours of lower consumption and its supplying during peak
hours. The whole storage capacity of the 29 reservoirs is of 194,159 m3.
All the pumping stations are connected through 4 sub-centres, with a command centre located
in San Siro station, which automatically optimises the operations of water collection from
wells and network pumping. Indeed, thanks to a telemetry system it receives data concerning
the operative conditions of each pumping station (pressures downstream pumps, output flow
rates, water level in reservoirs) and on the basis of these information it establishes, which
pumps have to work or to stop in order to keep constant pressure conditions in the whole
network. Both well and station pumps can indeed be controlled through a remote system.
Each well has its own pumps, hence 549 well electro pumps with a flow rate between 30 and
40 l/s are installed. Moreover each station is equipped with 3 or 4 pushing pumps with a flow
rate variable between 250 and 400 l/s. Altogether, 101 pumps with an installed power of
around 67,350 kW can run water into the network with a maximum flow rate of 32,000 l/s.
During the year 2009 only 433 of the 549 wells were in function while the remaining 116
were at a standstill for pollution problems. The total volume supplied was of 234,572,350 m3
while that actually consumed by users was of only 208,570,708 m3, meaning that about 11%
of losses occur within the network. Of the volume supplied, about 76.4% (179,259,049 m3)
was purified while the remaining only treated by disinfection.
The distribution network has a total length of 2,356 km, excluding users derivations, with
pipes of a nominal diameter variable between 80 and 1,200 mm and manufactured of steel,
grey cast iron or nodular cast iron.
Water was delivered at an average tariff of 0.486 €/m3, out of taxes, which corresponds to a
net value of about 0.5 €/m3.
223
System boundaries
The processes included in the inventory are those associated with energy, chemical reagents
and activated carbon consumptions nearby the treatment stations. Moreover, also an estimate
of the burdens associated with the life cycle of infrastructure materials is performed, in order
to evaluate if their more relevant presence within the system, with respect to the case of
bottled water, can give an important contribution to the environmental performances of the
scenario. In particular, materials employed for water supply network, activated carbon filters
and aeration towers manufacturing as well as for reservoirs and pumping stations construction
are accounted for. The possibility of an additional stage of quality improvement carried out
with a domestic depurator is also considered as well as the life cycle and the periodical
washing in a residential dishwasher of a reusable glass jug, employed to conserve water in
substitution of bottles.
The major upstream life cycle processes considered for the scenario under investigation and
that will be described during the inventory carried out in this paragraph are represented in
figure D.4.
Reference flow
As in the case of bottled water, the reference flow of the inventory is assumed to be “1 litre of
tap water delivered to the consumer and further purified”. All inputs and outputs to and from
the system have been related to this flow.
Data source
Data concerning energetic and raw material consumptions of the purification and delivering
system are primary and directly provided by Metropolitana Milanese, as well as those relative
to the materials employed for water supply network, activated carbon filters and aeration
towers manufacturing. Water reservoirs and treatment stations construction as well as
domestic purification and jug dishwashing are instead modelled through literature data. Also
in this case, inventory data employed to model raw materials production and energy
generation are taken from the widespread Ecoinvent data base if not otherwise specified.
224
Detailed inventory
Natural resources consumptions
The main natural resource consumed for tap water supplying is the water itself. The most
important factor influencing its consumptions are network losses, which can be estimated by
considering the difference between the annual volume of water introduced into the network
and the one effectively consumed by the users. For the year 2009, these lasts amounted
respectively to 234,572,350 m3 and 208,570,708 m3, meaning that losses are equal to about
11.1% and 1.12 litres have to be collected to supply 1 litre to the users.
Water consumptions associated with activated carbon filter backwashing have not been
possible to quantify but are estimated to be of negligible entity by the company.
Energy consumptions
Only electricity is consumed at the various treatment stations for an amount that during 2009
was of 101,186,808 kWh; of these about 1/3 are associated with pumping from wells and
water treatments and 2/3 with pumping into the network.
In view of the 208,570,708 m3 supplied to the users a specific consumption of 0.485 kWh/m3
or 0.000485 kWh/litre can be calculated.
The module Electricity, medium voltage, at grid/IT provided by Ecoinvent is utilised to model
the burdens associated with electricity generation.
Raw materials consumptions
Main raw materials consumptions are represented by filters granulated activated carbon
(GAC) and chemicals employed for water treatment.

Activated carbon
Activated carbon consumption can be estimated by considering that the overall volume of
filters installed at the various treatment stations amounts to 6,200 m3. Considering that a
minimum bulk density of 480 kg/m3 is required by the contract specifications, a
corresponding mass of 2,976 tonnes can be calculated. Carbon life span is of about 12-16
225
months, as a function of the quality of the treated water, before that its adsorption capacity
gets exhausted. After that it is sent to reactivation where, each time, about 5% losses occur
because also part of the carbon is oxidised during this process. This average value is strictly
specific for activated carbon utilised at the treatment stations in Milan because, how will be
better explained in this paragraph, it is a function of the level and the quality of carbon
contamination.
Considering therefore an average carbon life span of 14 months, the mass of activated carbon
required to deliver 1 litre of water is equal to:
M GAC 
2,976,000 kg
 1.22  10 -5 kg/litre
1 year
litres
14 months 
 208,570,708  10 3
12 months
year
From a theoretical point of view the activated carbon life cycle can be modelled as a case of
closed-loop recycling, how schematically depicted in figure 4.6 in relation to the value just
now calculated.
Activated carbon
production
0.05×(1.22×10-5)= 6.11×10-7 kg/litre
Activated carbon
utilization
0.95×(1.22×10-5)=1.16×10-5 kg/litre
1.22×10-5 kg/litre
Activated carbon
reactivation
Losses (aeriforms)
6.11×10-7 kg/litre
Figure 4.6: Conceptual model of the life cycle of the activated carbon utilised at the treatment stations at the
service of the aqueduct of Milan modelled as a case of closed-loop recycling
As it can be observed, performing reactivation in such a system reduces the needs of virgin
carbon production to the only 5% of losses that take place during the reactivation itself. The
processes that have to be considered to model the activated carbon life cycle are therefore:
226

virgin production of 6.11×10-7 kg of carbon and

reactivation of 1.22×10-5 kg of exhausted carbon.
The manufacturing process of virgin carbon is approximated with that of carbon coke by
means of a module built up with data provided by the ANPA I-LCA database (ANPA, 2000) .
The process of carbon reactivation is instead modelled with data available in the
environmental declaration of the company SICAV S.r.l. (SICAV, 2009), that is one of the
realities to which is farmed out the reactivation of the carbon employed by the Anconella
drinking water treatment plant, which will be examined in the next preventive scenario (waste
prevention scenario 1B, chapter 4.9).
The thermal reactivation of exhausted carbon at SICAV is carried out in two different rotary
kilns, one aimed at processing carbons deriving from drinking water or other food
applications and one at dealing with those deriving from wastewater treatment or from the
adsorption of solvents and other gaseous compounds. The use of two different kilns allows to
avoid contamination of products intended for alimentary applications with products destined
to industrial applications. The first kiln is also employed to activate virgin raw materials,
activity which is however of secondary importance at SICAV. The simplified layout of the
reactivation process, which will be now briefly described, is schematically depicted in figure
4.7.
When arriving at the plant the carbon is firstly stocked in silos and analysed to verify if the
typology of its contamination is compatible with reactivation or if it have to be substituted
with virgin feedstock. In affirmative case it is withdrawn from silos and introduced into a
hopper that feeds the kiln, which temperature is adjusted as a function of carbon
contamination typology, defined through the preliminary analysis. The residence time of
carbon in the kiln is also a function of this last parameter and is modified by adjusting the
feeding rate from the hopper. So activated carbon is then naturally cooled into a cooling
tunnel and sieved in its different granulometries. Each kiln has its own sieve, always to avoid
contamination. Sieved carbon is then analyzed and, if the target quality parameters are
respected, is stocked as loose product or packaged in 1 m3 plastic big-bags or 25 kg paper
sacks.
Raw gases originating in the kiln from the reactivation of food grade carbons undergo dust
removal through a cyclone and further wet scrubbing with water which pH is then neutralized
with a caustic soda solution. Those originating from the reactivation of wastewater/industrial
227
grade carbons need instead to undergo a post-combustion stage before wet scrubbing. Dusts
originating from sieving are also sucked and removed from the air stream trough a fabric
filter. Gaseous streams from kilns and sieving are release in atmosphere from two separate
chimneys.
Chimney 1
(E1)
NaOH
Stocking in
silos
Carbon reactivation in
rotary kilns
Food grade
kiln
Gas sucking
Industrial
grade kiln
Gas scrubbing
with water
Residual
water
Post-oxidation
Residues
Natural cooling
Air sucking
Sieving
Fabric filter
Chimney 2
(E2)
Residues
Packaging
and stocking
Figure 4.7: Simplified layout of the exhausted activated carbon reactivation process at SICAV (Adapted from
SICAV (2009))
The reactivation process in the kiln mainly consists in introducing steam in reverse current
with respect to the carbon flow. Steam is generated by means of a methane burner sited at the
end of the kilns and its temperature depends from the typology and level of contamination of
the carbon to reactivate, but it generally reaches a maximum temperature above 900 °C. In
this way carbon is subjected to an increase temperature gradient during its pathway into the
kiln in which its adsorbing capacity is partly restored by destroying adsorbed organic
compounds through a process which can be substantially subdivided in 4 stages, while carbon
advances in the kiln:
1) At the initial temperature of about 100-200 °C, the major part of water is desorbed
together with high volatile organic compounds (which can be oxidised in presence of
possible residual oxygen);
228
2) Between 200 °C and 500 °C, residual water is evaporated and less volatile compounds
are desorbed or decompose originating smaller molecules which volatilize or, under
the effect of high temperatures, react to give heavier compounds which remain within
porosities;
3) Reached 500°C and till to 700°C, not desorbed compounds are pyrolysed originating a
carbonic residue (coke) which occlude porosities;
4) Oxidation of the pyrolysed residue (C) through steam (water) and carbon dioxide
(CO2) at temperature higher than 700 °C (but generally higher than 900 °C), through
the following reaction:
C (s)  H 2 O (g)  CO (g)  H 2 (g)
C (s)  CO 2 (g)  2 CO (g)
so formed CO can therefore react with steam (water) to give CO2:
CO (g)  H 2 O (g)  CO 2 (g)  H 2 (g)
(part of the water comes also from methane combustion).
Losses of the original carbon varying from 5% to 25% occur during reactivation because it is
partially oxidised together with the pyrolysed residue, according to the previous reactions. A
secondary effect is the partial destruction of microporosities which involves a certain
reduction of the carbon capacity to adsorb small compounds.
The operation of the two kilns is alternative so that the respective methane consumptions and
airborne emissions can be quantified separately.
SICAV declaration reports the major consumptions that have been occurred at the plant since
the year 2004 up to June 2009. They mainly concern methane employed to generate steam
and to heat the kilns, and electricity required for all the operations and all the machineries of
the productive line, for services and to charge batteries of warehouse trucks employed for
internal handling of carbon. Part of these are fed by diesel and therefore also small amounts of
this fuel are needed. Caustic soda consumptions are provided only from the year 2007 and
refer to the acquired amount and not to that actually utilised, but these were however
considered as an approximation. Only the overall volume of water consumed for kilns
cooling, gas washing and auxiliary services is reported, without separating the various
contributions. Methane consumptions are specific for the food grade applications kiln, while
229
the remaining ones are overall values. The amount of residual gas washing water generated as
waste is also reported.
Table 4.29 shows the entity of these inputs and outputs occurred during the whole period
2004-June 2009 calculated on purpose by summing up those pertaining to each single year. In
the same table, the values associated with the reactivation of 1 tonne of carbon are also
reported. These are calculated by dividing the previous values by the total amount of
exhausted carbon sent to reactivation during the same period, reported in table 4.30. One
exception is methane, for which the only amount of exhausted carbon deriving from food
grade applications was considered to define its specific consumption, for the reasons
explained above.
Table 4.29: Major inputs and outputs to and from the exhausted activated carbon reactivation process at SICAV
S.r.l. for the period 2004 - June 2009 (SICAV, 2009)
Amount
Specific consumptions
(2004-June 2009) (Unit/t carbon to reactivate)
Methane (for the food grade applications kiln) m3
1,226,068
57.8
Electricity
kWh
986,723
35.1
Diesel (for internal transport)
litre/s
21,655
0.771
Caustic soda (30% m/m solution)*
kg
2,600
0.193
3
Water (cooling, gas washing, services)
m
3,282
0.117
Residual water from gas washing
kg
227,804
8.11
(*) The solution titre is estimated considering that 1 m3 tank of 1,300 kg was purchased both in 2007 and
2008 and that a density of 1.3 kg/litre is a typical value of a 30% solution
Input/Output
Unit
Table 4.30: Amount of exhausted activated carbon sent to the reactivation process at SICAV S.r.l. during the
period 2004 – June 2009 (SICAV, 2009)
Exhausted carbon sent to reactivation (kg)
Origin
Amount (2004-June 2009)
From food-grade applications
21,229,390
From industrial-grade applications
6,860,101
Total
28,089,491
With regard to airborne emissions, those deriving from activation kilns appear to be
associated, other than with methane combustion, also with the activation reactions above
described and, in last instance, with the level and the typology of pollutants adsorbed on the
exhausted carbon. Emissions of carbon monoxide (CO), carbon dioxide (CO2) and not
oxidised organic compounds (VOC) can be therefore expected from the only desorption
process and activation reactions. For the present inventory, the emissions of CO, VOC,
nitrogen oxides (NOx) and particulate (from both kilns and sieving processes), reported into
230
the SICAV environmental declaration, are firstly considered. They are presented in table 4.31
either in absolute terms for the period 2004-June 2009, or in specific terms (per tonne of
carbon to reactivate).
Table 4.31: Airborne emissions originating from the exhausted activated carbon reactivation process at SICAV
S.r.l. during the period 2004 – June 2009 (SICAV, 2009)
Total emissions
Specific emissions
(2004-June 2009) - kg (g/t carbon to activate)
Carbon monoxide (CO)
4,461
210.1
Volatile organic compounds (VOC)
200
9.4
From kiln
Nitrogen oxides (NOx)
5,836
274.9
Particulate (unspecified)
653
30.8
From sieving Particulate (unspecified)
146
6.9
Origin
Pollutant
Considering the data reported in table 4.29 and 4.31 a new module Exhausted carbon
reactivation was therefore established to model the reactivation process of 1 tonne of
exhausted activated carbon on the basis of the following considerations.
Firs of all, since CO2 emissions were not considered in the report, a Ecoinvent dataset
modelling the burning of methane within an industrial furnace (Natural gas, burned in
industrial furnace >100kW/RER) was associated to the amount of methane reported in table
4.29, instead of a dataset simply modelling methane delivering. This in order to account at
least for CO2 emissions potentially originating from methane combustion, as well as of the
emissions of those pollutants not specified by the considered source, but instead specified in
the Ecoinvent module. In this last, emissions of CO, NOx and particulate was however
neglected in order to avoid their double counting as well as the amount of associated
electricity consumption, which is considered to be already included in the one reported in
table 4.29.
No specific information were available concerning the typology and the possible burdens of
the treatment of residual gas washing water and therefore, in order not to totally neglect its
burdens, it was approximated with a process describing the treatment of an unpolluted sewage
into a wastewater treatment plant, represented by the Ecoinvent module Treatment, sewage,
unpolluted, to wastewater treatment, class 3/CH.
With regard to the remaining consumptions, the following modules are finally employed to
account for their production burdens:

Electricity: Electricity, medium voltage, at grid/IT;

Diesel: Diesel, low-sulphur, at regional storage/RER;

231

Caustic soda: Sodium hydroxide, 50% in H2O, production mix, at plant/RER ;

Water (as natural resource): Water, process and cooling, unspecified natural origin.
Sodium hypochlorite
The most important chemicals utilised at treatment stations is sodium hypochlorite (NaClO)
for water disinfection. It is dosed in an amount of 0.15-0.2 mg/l as pure hypochlorite, to
assure a content of residue chlorine in the network equal to 0.05 mg/l. A solution with a titre
of 14% (m/v) as active chlorine is employed and its consumption for the year 2009 was equal
to 179,624 kg. Considering that a density of 1.22 kg/litre is a common value for this typology
of solution, it is possible to calculate the amount consumed of pure substance as:
M NaClO  179,624 kg sol 
0.14kg Cl 2 /l sol. 74 kg NaClO

 21,484 kg NaClO
1.22 kg sol/l sol.
71 kg Cl 2
In view of the 208,570,708×103 litres delivered to the users, the specific consumptions of
solution and of active substance are therefore equal to 8.61×10-7 kg/litre and 1.03×10-7 kg/litre
respectively. The burdens associated with the manufacturing of sodium hypochlorite are
modelled with the Ecoinvent dataset Sodium hypochlorite, 15% in H2O, at plant/RER which
models its production from the reaction of sodium hydroxide and chlorine. This last is
assumed to be a by-product from other processes and therefore does not carry any burdens in
the system.
Also cryogenic CO2 is employed in those treatment stations which foresee VOC stripping in
aeration towers and which deal with waters of particular hardness, to avoid carbonate
precipitation. But it was not possible to quantify this consumption. Moreover, a periodical
washing of the filling material is carried out through a descaling solution, which
consumptions are estimated to be of negligible entity by the company.
Table 4.32 summarizes energy and raw material consumptions attributed to the system and
the respective SimaPro module employed for the modelling of the respective burdens.
232
Table 4.32: Energy and raw material consumptions involved in drinking water treatment and delivering to the
city of Milan
Material/Energy
Water
Unit
litre
Absolute value
234,572,350
Unit/litre
1.12
Electricity
kWh
101,186,808
0.000485
SimaPro Module1
Water, well, in ground
Electricity,medium
voltage, at grid/IT
 Carbon coke
 Exhausted carbon
reactivation
2,976,000
1.22×10-5
Activated carbon (GAC) – total
148,800
6.11×10-7
 modelled as virgin
kg
production
2,827,200(2)
1.16×10-5(2)
 modelled as reactivated
Sodium Hypochlorite (NaClO) –
179,624
8.61×10-7
Sodium hypochlorite,15%
14% (m/v) as active Cl solution,
kg
in H2O, at plant/RER
(NaClO – pure substance)
(21,484)
(1.03×10-7)
(1) In italic the modules taken from Ecoinvent database
(2) In order to obtain 1.16 ×10-5 kg of reactivated carbon, 1.22×10-5 kg have to be sent to reactivation and the
respective module has to be recalled with this amount
Wastewaters which originates during activated carbon filters backwashing are not
contaminated and have only a negligible sand content (around 0.1% as volume), therefore,
they are suitable for direct sewage draining. This consideration is also valid for retentate
originating from reverse osmosis treatments carried out at the Gorla station. Moreover, no
production of sludge occurs during water treatment. As consequence, no meaningful
waterborne emissions are attributed to the process of water treatment.
Infrastructures
In order to evaluate if the wider utilisation of infrastructures for tap water delivering with
respect to that associated with bottled water delivering (at least, in the case of the city of
Milan) can have a relevant influence on the environmental performances of the scenario itself,
we have tried to take the respective burdens into account.
New inventories are established to model the life cycle of the materials constituting the water
supply network, activated carbon filters and aeration towers. For water reservoirs, pumps and
treatment stations building materials already existing modules available from the Ecoinvent
database are instead employed.

233
Water supply network
The water supply network of the city of Milan is composed by 2,356 km of pipes (excluding
user derivations), of which:
-
15% of steel,
-
20% of nodular (ductile) cast iron,
-
65% of grey cast iron.
Pipes nominal diameters () are instead distributed in the following intervals:
-
12% with  < 150 mm,
-
72% with 150 mm ≤ ≤300 mm,
-
11% with 350 mm ≤  ≤ 500 mm,
-
5% with  > 500 mm.
All the reported values refer to the total length of the network, while the distribution of each
material by typology of diameter is unknown. For this reason the analysis is carried out by
considering the simplifying assumption that the total length of the pipes manufactured of a
given material is subdivided according to the distribution of diameters which characterize the
whole network reported above.
Considering that the current composition of pipes age is the following:
-
22% more than 70 years,
-
16% between 50 and 70 years,
-
-
-
6% less than 10 years,
it is also possible to estimate the average life span of pipes by calculating the weighted
average of the respective ages, which results to be of about 45 years if the central value of
each class is considered. This value will be employed in carrying out the inventory.
The total length of steel pipes results to be equal to 353.4 km (15% of 2,356), and by
employing the distribution of diameters reported above it is then possible to subdivide the
calculated length by typology of diameter, as presented in the third column of table 4.33.
In order to calculate the mass of steel constituting network pipes, the linear masses reported in
the catalogue of the company Dalmine Tenaris Group (Tenaris, 2007) which manufactures
and commercializes also steel pipes for gas and water transport, have been taken as reference.
In particular the linear mass ascribed to the four diameters intervals of interest is calculated by
234
averaging those of the diameters which belong to that interval, as showed in table 4.34 and
synthetically in the fourth column of table 4.33.
By multiplying these last values by the length of steel pipes of each diameters interval, it is
finally possible to calculate the total mass of steel constituting the network which results
equal to 16,499,822 kg, as presented in the last column of table 4.33.
Table 4.33: Lengths and masses of steel pipes subdivided by diameters interval
Nominal diameters ()
(mm)
 < 150
150 ≤  ≤ 300
350 ≤  ≤ 500
 > 500
Total
%
12
72
11
5
100
Steel pipes
Length Average linear mass
(km)
(kg/m)
42.4
7.49
254.4
39
38.9
88.5
17.7
159.5
353.4
-
Mass
(kg)
317,636
9,923,472
3,440,349
2,818,365
16,499,822
Table 4.34: Schematization of steel pipes average linear mass calculation for each diameters interval
Diameter
interval
(mm)
 < 150
150 ≤  ≤300
350 ≤  ≤ 500
 > 500
Steel pipes
Nominal
Linear
diameter
mass
(mm)
(kg/m)
40
2.93
50
4.11
65
5.24
80
6.76
100
10.9
125
15
150
18.2
200
31
250
41.4
300
65.4
350
68.6
400
83.4
450
94
500
108
600
141
700
178
Average
linear mass
(kg/m)
7.49
39
88.5
159.5
In order to refer the amount of steel calculated above to 1 litre of supplied water, it is
necessary, as usual, to divide it by the volume of water delivered by the pipes during their
estimated life span (45 years):
M steel 
16,499,822 kg
 1.76 10 6 kg/litre
3
208,570,708 10 litres/yea r  45 years
235
The same procedure is followed for cast iron pipes but without considering the subdivision
between nodular and grey cast iron, since no separated datasets concerning the respective
manufacturing processes are available in the database.
The total length of cast iron pipes is equal to 2,002.6 km (85% of 2,356 km) and the linear
mass of the pipes belonging to the four diameters intervals reported above are defined by
averaging the values available in the catalogue of the company Sertubi Duferco Group
(Sertubi Duferco Group, 2010) which manufactures nodular cast iron pipes for water
networks (table 4.35).
As done before, the length of the pipes belonging to each diameters interval is first calculated
through the percentages provided above and then the total mass of cast iron employed for
pipes manufacturing is obtained on the basis of the average linear masses ascribed to the
respective diameters interval through the same procedure followed above. All the results are
presented in table 4.36.
Table 4.35: Schematization of cast iron pipes average linear mass calculation for each diameters interval
Cast iron pipes
Diameter
interval (mm)
 < 150
   300
   500
  500
Nominal
diameter
(mm)
Linear
mass
(kg/m)
60
80
100
125
150
200
250
300
350
400
450
500
600
700
800
11.5
15
18.5
23
27.5
37
48
61
80.5
95.5
113
131
170
218
267
Average
linear
mass
(kg/m)
17
43
105
218
236
Table 4.36: Lengths and masses of cast iron pipes subdivided by diameters interval
Nodular and grey cast iron pipes
Nominal diameters
Length
Average linear mass
Mass
%
(km)
(kg/m)
(kg)
() (mm)
12
240.3
17
4,085,304
 < 150
72
1,441.9
43
62,541,198
150 ≤  ≤ 300
11
220.3
105
23,130,030
350 ≤ ≤ 500
5
100.1
218
21,861,717
> 500
Total 100
2,002.6
111,618,249
The network results to be constituted by an overall amount of 111,618,249 kg of cast iron
which corresponds to a specific amount of 1.19×10-5 kg/litre.
Steels are iron alloys with a carbon content lower than 2.1% and can be classified in
unalloyed (or carbon) steels and low-alloyed steels, on the basis of their content of alloying
elements. A particular category is represented by stainless steels which are alloys containing a
minimum of 10.5% of chromium with other elements such as nickel and molybdenum in
order to improve their resistance to corrosion. Steels can be manufactured with two
completely different processes: from iron ores reduction into basic oxygen furnaces (primary
production) or from re-melting of production scraps and post consumer scraps into electric arc
furnaces (Classen et al., 2009). From the technical data reported in Tenaris (2007), we have
recognized that carbon steel is employed for pipes manufacturing while Classen et al. (2009)
assumes that, in Europe, steel is manufactured on average for 63% in basic oxygen furnaces
and for 37% in electric arc furnaces. For this reason, the Ecoinvent dataset Reinforcing steel,
at plant/RER, which models the manufacturing of carbon steel ingots through these two
technologies in the mentioned percentages, and which already includes the process of sheets
hot rolling from ingots, is employed to model the production of carbon steel constituting
network pipes. Moreover, always from Tenaris (2007), it is possible to recognize that the
whole range of available diameters is covered by seamless tubes while welded ones reach
only the diameter of 200 mm. Therefore the module Drawing of pipes, steel/RER which
models the drawing of seamless tubes is employed to model the conversion process of steel
sheets into pipes.
Cast iron is an alloy of iron and carbon in the range of 2.8 – 4% as weight, which properties
can be adjusted within a wide range by adding different typologies of alloying elements that
change the metallic structure of cast iron. For example, grey cast iron is a very brittle type of
237
cast iron because of its graphitic structure. On the contrary, nodular (or ductile) cast iron is
produced by adding magnesium to the melted iron which allows the carbon to form tiny
spherical nodules around itself, giving to cast iron ductility and shock resistance. Cast iron is
produced by re-melting pig iron with iron scraps and steel. Pig iron is an alloy of 94% of iron
and more than 2% of carbon, obtained by processing iron bearing element, such as iron ore,
and coke within a blast furnace (Classen et al., 2009).
No distinction is made in the database between the production process of grey or nodular cast
iron and therefore the general module Cast iron, at plant/RER is employed to model cast iron
ingots production. According to Sertubi Duferco Group (2010), in order to produce pipes,
melted cast iron is centrifuged into a cylindrical shape and baked again into a oven. The
external surface is then zinc-coated while the internal one is coated with a layer of cement
mortar. This conversion process is not inventoried in the database and it is therefore modelled
for simplicity through the same module employed for steel pipes (Drawing of pipes,
steel/RER) with the difference that also the process of ingots hot rolling in sheets have to be
considered (Hot rolling, steel/RER). The amount of zinc and cement mortar required for
coating are derived from Ecoinvent and result to be equal respectively to 6.9 gzinc/kgc.iron and
25 gc.mortar/kgc.iron, which correspond to 8.20 ×10-8 kgzinc and 2.99 ×10-7 kgc.mortar per litre of
delivered water.
Finally we have decided to account for pipes employed for users derivations. To this end, also
on the basis of the indications provided by the same Metropolitana Milanese, the about 50,000
users served by the aqueduct of Milan are assumed to be linked with the public network
through one high density polyethylene (HDPE) pipe with an average length of 10 meters and
a nominal diameter of 50 mm. According to the information provided in the catalogue of the
company Oppo (Oppo, 2010), one HDPE 80 pipe with 3 mm thickness, resistant to a nominal
pressure of 8 bar and with a nominal diameter of 50 mm, is characterized by a linear mass of
0.45 kg/meters. The mass of HDPE required for the supplying of 1 litre of water is therefore
equal to:
M HDPE 
0.45 kg/m  10 m/user  50,000 users
 2.4  10 8 kg/litre
3
208,570,708 10 litres/yea r  45 years
238
HDPE granules are converted into pipes through an extrusion process whose inventory is
available in the Ecoinvent database (Extrusion, plastic pipes/RER) and which is therefore
employed to model pipes manufacturing from virgin HDPE granules (Polyethylene, HDPE,
granulate, at plant/RER), by considering a conversion efficiency of 99.6%.
Table 4.37 summarizes the specific amount of pipes materials required by the system.
Table 4.37: Specific masses of pipes manufacturing materials attributed to the system
Pipes material
Amount (kg/litre)
Steel
1.76×10-6
Cast iron (grey and nodular)
1.19×10-5
HDPE
2.4×10-8
All pipes materials are assumed to be recycled at the end of their useful life span through the
processes already described in paragraph 3.3.2 and during the inventory of bottled water in
paragraph 4.5.2 (Steel recycling for steel and cast iron pipes and HDPE granules from
containers recovery for HDPE pipes).
All these processes are utilised to build up the module Water supply network created by
modifying the homonymous dataset already available in Ecoinvent, from which the processes
associated with excavation through hydraulic diggers and laying of pipes through building
machines are also derived.

Activated carbon filters and aeration towers material
The information provided by Metropolitana Milanese indicate that both filters and aeration
towers have a diameter of 3 meters and an height of between 5 and 6 meters. Towers are
manufactured of stainless steel except for the 6 of the Cimabue treatment station which are
made of alimentary grade polypropylene. Some filters are made of stainless steel and others
of painted carbon steel.
Assuming that filters and towers can be approximated to hollow cylinders with sides of a
thickness (t) of 2 mm and an average height of 5.5 meters, the volume of material required to
manufacture one unit is equal to:


Vunit  πr 2  t  2  2π  r  h  t   (π  32 m 2  0.002m)  2  2π  3m  5.5m  0.002m   0.32 m 3
Assuming that half of the activated carbon filters (256/2=128) are made out of stainless steel,
considering that the number of aeration towers in this material is equal to 25 and that the
239
density of a 18/8 stainless steel is of about 7,930 kg/m3, it is therefore possible to calculate the
mass of stainless steel required by the system, as follow:




M steel  Vunit  7,930 kg/m 3  128  25  0.32 m 3  7,930 kg/m 3  153  388,253 kg
In view of the 208,570,708 m3 yearly produced and of an assumed life span of 30 years, the
mass of steel required to deliver 1 litre of water is therefore equal to:
M steel /l 
388,253 kg
 6.205 10 8 kg/litre
3
208,570,708  10 litres/yea r  30 years
Repeating the same calculations for the 6 polypropylene aeration towers by assuming a
density of 910 kg/m3 for this material, the mass of polypropylene required by the system
results to be equal to 1,747.2 kg or either 2.79×10-10 kg/litre.
Finally, considering that the density of a generic carbon steel is equal to 7,850 kg/m3, the
mass of material associated with the remaining 128 activated carbon filters, calculated with
the same procedure, is equal to 321,536 kg or either 5.14×10-8 kg/litre.
A synthesis of the results obtained from the previous calculations is reported in table 4.38.
Table 4.38: Specific masses of activated carbon filters and aeration towers manufacturing materials attributed
to the tap groundwater system
Material
Facility
Amount (kg) Specific amount (kg/litre)
Stainless steel 128 filters+6 towers
388,253
6.205×10-8
Carbon steel
128 filters
1,747.2
5.14×10-8
Polypropylene
6 towers
321,536
2.79 ×10-10
On the basis of the same considerations done for steel pipes, the modules Chromium steel
18/8, at plant/RER and Reinforcing steel, at plant/RER are chosen to model, respectively, the
production of stainless steel and carbon steel hot rolled sheets. These lasts are assumed to
undergo a further process of cold rolling (Sheet rolling, steel/RER) to become suitable for the
application in filters and towers manufacturing.
Finally, the conversion process of virgin polypropylene granules (Polypropylene, granulate,
at plant/RER) in towers is approximated with that of injection moulding (Injection
moulding/RER). As in this case of pipes, all materials are assumed to be recycled at the end of
240
their useful life (Steel recycling, discussed in paragraph 4.5.2 and Recycling PP B250 taken
from the Buwal 250 database).
With regard to pumps and pumping stations building materials we have chosen to employ, as
an approximation, the module Pump station/p/CH already available in the Ecoinvent
database. It accounts for the burdens associated with land use, manufacturing and end of life
of the materials employed in pumps and building manufacturing of one pumping station in
Switzerland. Unfortunately the number of pumps which are considered to constitute the
station itself, which in the case of Metropolitana Milanese vary between three and four units
per stations, is unknown.
The module has to be recalled with a factor determined by considering that the number of
treatment stations which serve the city of Milan is equal to 29 and assuming an estimated life
span of 70 years, as indicated in the database. An amount of 1.99 ×10-12 pump stations/litre is
resulted.
The last important infrastructures belonging to the treatment stations are water reservoirs
where water is disinfected and stored before its pumping into the network. Also in this case,
we have chosen to employ the already available module Water storage/CH/I which
inventories land use, materials manufacturing and disposal of a 2,500 m3 water reservoir in
Switzerland. The amount of this module which has to be recalled can be estimated by
considering that the whole storage capacity nearby the treatment stations of Metropolitana
Milanese is of 194,159 m3 and that a life span of 70 years is considered in the database, as for
pumping station:
No.reservoirs 
194,159/2,500
 5.32  10 12 reservoirs/litre
3
208,570,708  10 litres/yea r  70years
All the processes described up to now are employed to build up the module Tap water, at
user, from groundwater which models the public purification and the delivering of 1 litre of
groundwater from the tap to domestic users.
241
Domestic depuration of water
As anticipated, we have also considered the case in which a domestic depurator is employed
by users to further improve water quality.
As outlined in paragraph 1.5, the market offers a quite wide range of different technologies
and, of consequence, with different features and level of consumptions. In this study three
equipments based on the same technology, which foresees a first passage of water through an
activated carbon filtering cartridge and a subsequent stage of filtration on one or two osmotic
membranes are assumed as reference. Since the water treated in this way is deprived of its
content of minerals, it is mixed in a certain amount with not filtered water to allow the
restoration of hardness at the point of use, as required by the Italian legislation (Ministerial
Decree 443/90). Moreover, in order to allow a continuous feeding, a fraction of the incoming
flow rate is lost (recovery rate less than 1).
Main technical features of the examined equipments are summarized in table 4.39 together
with the values chosen as representative for this study. In particular from the ratio between the
installed power and the average flow rate, it is possible to calculate the theoretical specific
consumptions of electricity while, from the recovery rate, the actual amount of water
withdrawn from the network. Finally, by considering that a 0.5 kg activated carbon filter have
to be substituted once a year, it is possible to associate this mass with the delivering of 1 litre
of purified water on the basis of the annual volume that has to be supplied under each
scenario (500 g/152 litres/year=3.3 g/litre). Sources of data are Osmotek (2007), Lux (2010)
and Osmo System (2010).
Table 4.39: Technical features of domestic depurators and estimated energy and material consumptions
employed in this study
Parameter \ model
Power (W)
Flow rate (litres/h)
Specific
consumption (kWh/l)
Recovery rate
(Qout/Qin)
Activated carbon
filter (n°×kg)
Osmotek Ultratech NF100
180
70-100 (85)
Lux - Mosè
300
100
2.12×10-3
3×10-3
Osmo system Osmy Smart
180
60-70 (65)
2.77×10-3
Assumed in this
study
2.63×10-3
(Average)
1:3
n.a.
n.a.
1:3
1 by 0.5 kg
substituted once a
year
1 substituted once
a year
1 substituted once a
year
1 by 0.5 kg
substituted once
a year
242
The module Purified water by domestic depurator, described in table 4.40, is created to
account for these energy and material inputs, disposal of activated carbon (in landfill) and the
treatment of discharged water (about 2 litres/litre) , considered as an unpolluted sewage, at
wastewaters treatment plant. In particular consumed water brings all the burdens associated
with its purification and delivering up to the point of use and therefore the module described
before in this paragraph (Tap water, at user, from groundwater) which accounts for all these
burdens is employed to model water consumptions.
Table 4.40: Major features of the SimaPro module which models the process of domestic depuration of water
Materials/Energy/Processes
Unit
Water
Electricity
Activated carbon (GAC) manufacturing
litres
kWh
kg
Amount
Unit/litre
3
2.63×10-3
3.3×10-3
kg
3.3×10-3
litres
2
Landfilling of activated carbon filter
Treatment of rejected water
SimaPro Module1
Tap water, at user, from groundwater
Electricity, medium voltage, at grid/IT
Carbon coke
Disposal, inert waste, 5% water, to
inert material landfill/CH
Treatment, sewage, unpolluted, to
wastewater treatment, class 3/CH
Glass jug life cycle and washing
Nearby the consumers, water is assumed to be conserved within a 1 litre glass jug, assumed,
for simplicity, to have a mass equal to the one of glass bottles employed in the next refillable
bottled water scenario (475 g/jug, paragraph 4.10.2) and a conservative life span of 1 year.
This means that, in view of the about 152 litres that have to be supplied under each scenario,
the amount of glass associated with the delivering of 1 litres of water is equal to 3.12 g/litre
(475 g/152 litres/year). Glass jug is assumed to be recycled at the end of its useful life and its
life cycle is modelled trough the closed-loop approach as will be made in the refillable glass
bottled water scenario, to which we refer for further details (paragraph 4.10.2). The module
Glass jug is therefore built up on the basis of these considerations.
Jug is arbitrarily assumed to be washed every each four uses in a residential dishwasher as
part of a load of 30 items and of consequence 1/30 of the burdens associated with a
dishwashing cycle are assigned to the jug washing. These parameters will however undergo to
sensitivity analysis (paragraph 5.3).
243
Data about energy and water consumptions of a dishwashing cycle are taken from the web
site of U.S. EPA Energy Star program (Energy Star, 2010). In particular, they are calculated
by averaging the ones of 637 Energy Star qualified dishwashers and are reported in the first
column table 4.41. Considering that at the moment of each washing cycle the jug has already
contained 4 litres of water, specific consumptions, i.e. for electricity, can be calculated as
follow:
Ee dishwashin g 
1.32 kWh/cycle
 0.011 kWh/litre
30 items/cycl e  4 litres/ite m
The obtained results are summarized in the second column of table 4.41.
Table 4.41: Average energy and raw material consumptions of Energy Star classified dishwasher considered in
this study
Amount
Specific amount
(Unit/cycle)
(Unit/litre)
kWh
1.32
0.011
litres 15.7 (4.15 gallons/cycle)*
0.131
Dishwasher consumptions Unit
Energy (kWh/cycle)
Water (litres/cycle)
(*) 1 gallon = 3.785 litres
Because of data lacking, consumptions of detergents and the relative potential waterborne
emissions could not be quantified. Anyway, the treatment of the amount of water employed
during a washing cycle, considered as an un polluted sewage, at wastewaters treatment plant
is accounted for (Treatment, sewage, unpolluted, to wastewater treatment, class 3/CH). These
consumptions and processes are introduced in the module Jug washing in residential
dishwasher, created on purpose.
The processes concerning domestic purification and the life cycle and the washing of the jug
are utilised to build up the module Tap water, from groundwater, use at consumer house
which models the burdens associated with the domestic quality improvement of 1 litre of
already purified tap water as well as the ancillary processes associated with preserving water
nearby consumers.
The whole scenario is instead finally implemented in the module Waste prevention scenario
1A (Tap water - groundwater source) which simply account for the fact that 152.1 litres have
to be supplied through tap water, by recalling the module specified above.
244
The magnitude of the major processes described up to now which characterize the present
scenario are summarized in table D.4.
4.9 Waste prevention scenario 1B (Utilisation of public network water:
surface water from public fountains)
This preventive scenario considers the consumption of public network water having surface
origin. In particular the delivering system of the city of Florence and of its suburban area,
which are supplied by water withdrawn from the Arno river and purified at the Anconella
treatment plant, is considered.
The delivering of improved quality water from public fountains is also explored in this
scenario in substitution of its domestic depuration, by taking suggestion from the original
possibility given to the citizens of the analyzed context by Publiacqua, which is the holding
company of the whole integrated water service of the mentioned geographical area.
Waste generation is limited to the reusable glass bottles that will be assumed to be utilised to
conserve water, and to the periodically substituted consumable materials of the system
utilised to improve water quality at public level. Their contribution is however expected to be
of minimal entity and the burdens associated with their handling are excluded for simplicity
by the waste management system, but are directly accounted for in the inventory relative to
public network water supplying.
A certain amount of sludge is also generated from water purification and some considerations
about its relevance and comparability with the amount of waste generated in the other
investigated scenarios will be given in paragraph 5.2.1.
As for the scenarios investigated up to now, the inventory of the major upstream life cycle
processes associated with drinking water delivering through the system described above is
carried out in the following paragraph. These upstream processes are indeed those whose
magnitude change among the examined scenarios.
245
4.9.1 Life cycle inventory of public network water: surface water from public fountains
System description
The following description is mainly based on the information provided by several sources
such as Fabbri (2010), Publiacqua (2010a, 2010b, 2010c), Rossi (2010), Rossi (2007),
Moscatelli et al. (2006) and Santianni and Griffini (2004).
The Anconella water treatment plant is one of the most important Italian plants that treat
water from surface origin for the production of drinking water. In particular it treats water
withdrawn from the Arno river to make drinking water available to the city of Florence and to
its suburban area including the cities of Prato and Pistoia, served by a network which extends
over a length of about 900 km.
The plant is operated by the society Publiacqua S.p.A. which actually manages the whole
integrated water service of the Optimal Territorial Ambit (Ambito Territoriale Ottimale)
Medio Valdarno (ATO 3), which includes the provinces of Florence, Prato, Pistoia and part of
Arezzo.
The plant has a maximum productive capacity of 3,500 l/s but generally operates at an
average flow rate of 2,300 l/s. Its simplified layout is schematically depicted in figure 4.8.
Figure 4.8: Simplified layout of the Anconella drinking water treatment plant (Adapted from Fabbri (2010))
246
The water intake work is protected by a mobile barrier which avoids the entrance of possible
floating substances (i.e. oils), by a fixed sieve and by two mechanical sieves to hold back
coarse materials. Water reaches then an accumulation basin where it is raised up by 3 pumps
with a flow rate variable between 1,500 and 2,000 l/s and with an installed power of 373 kW
each one, and by two auxiliary submersible pumps with a flow rate of 1,000 l/s each one.
Being of surface origin, water undergoes a very intense chemical-physical treatment which
begins with a pre-oxidation stage through the introduction of chlorine dioxide (ClO2), directly
on the adduction pipe. It is dosed in measure of about 0.5 ppm with the aim of partially
remove oxidable pollutants, of achieving a pre-disinfection and of controlling algal growing.
Only in case of emergency or of high incoming organic load, powdered activated carbon
(PAC) is also introduced at this point with a dosage between 5 and 15 ppm.
The incoming flow is then distributed by a divider in two clarification and filtration lines to
remove suspended solids responsible of water turbidity. The first line is supplied by a
constant flow rate and is composed by 6 Dorr-Oliver settling basins with a maximum treatable
flow rate of 250 l/s, a surface of 615 m2 and an height of 5 m each one. The second one can
absorb flow rate variations and is composed by 4 Pulsator sludge blanket clarifiers with a
maximum flow rate of 625 l/s, a surface of 900 m2 and an height of 5 m each one. Both the
typologies of clarifiers combine the two functions of flocculation and settling in a unique
basin. The employed coagulant-flocculant agent is Poly-aluminium chloride (PACl) and is
introduced in correspondence of the overfall of the divider towers which split up the flow
among the clarifiers, exploiting in this way the energy of the hydraulic jump to carry out the
flash mixing stage required for the destabilization of the colloidal suspension. In particular
conditions of high incoming loads of suspended solids, organic polyelectrolytes are also
introduced in the clarifiers, in conjunction with the already added PACl, to improve flakes
formation and their settling rate. For this reason polyelectrolytes are required to be of Potable
Water Grade (PWG).
Decanted water reaches then gravity sand filters where the removing process of suspended
solid is completed. In particular the first line is composed by 18 quartziferous (siliceous) sand
filters with a filtering surface of 60 m2 and a bed height of 0.9 m, while the second line by 12
filters with a surface of 150 m2 and a bed height of 1 m. The employed sand has a
granulometry encompassed between 0.8 and 1.5 mm.
247
Between the clarifiers and the filters also sodium hypochlorite (NaClO) and chlorine dioxide
(ClO2) are added in a dosage of 1-4 ppm and 1-2 ppm respectively, for the control of the
ammonium ion (NH4+) concentration and to carry out an intermediate oxidation stage.
At the end of the filtration stage, together with suspended solids, also a partial abatement of
the microbial load and of organic substances is achieved, reducing the demand of oxidant
during the successive treatment of ozonization.
Ozone is added with a dosage of about 1 ppm in order to achieve a significant reduction of the
microbial load, the oxidation of organic pollutants (such as surfactants) and micro pollutants
(such as solvents and pesticides) and the improvement of water organoleptic quality (smell
and taste). Moreover, the biodegradability of the organic substances is probably increased.
It follows then a filtration stage on granulated activated carbon (GAC) filters which aims at
refining water quality by removing residual organic compounds and disinfection by-products
such as Trihalomethanes (THM), chlorites and other chlorine-derivates and bromates, in case
originated during the previous treatments. The organoleptic quality of water is also further
improved. A total of 14 filters with a filtering surface of 130.4 m2 and a bed height of 2.2 m
each one are installed nearby the plant. Besides the chemical-physical adsorption also the
biological adsorption is promoted in filters (BAC - biological activated carbon filtration) to
improve the removal of biodegradable organic substances.
Water is finally stored in one of the 3 available compensation basins where post-disinfection
is carried out through the addition of chlorine dioxide (ClO2) in a dosage between 0.5 and 0.7
ppm and assuring a contact time of 45 minutes in order to assure an adequate level of residual
chlorine in the distribution network. Just in this last water is finally introduced by 6 pushing
pumps with a flow rate of 1,000 l/s and an installed power of 710 kW each one, which
compose the pumping station of the plant.
Sand and activated carbon filters are periodically backwashed with water coming from the
same treatments and which is then reintroduced to the head of the plant.
Chemical sludge originating from the clarification processes are firstly stored in one
homogenization basin, thickened in two thickener basins and finally dehydrated through two
filter presses. The two processes are supported by the addition of anionic polyelectrolyte, the
first, and cationic polyelectrolyte the second. Dehydration water is reintroduced upstream the
thickeners, while the supernatant originating from these lasts is discharged into the Arno
river. Dehydrated sludge are finally destined to be employed for environmental restoring
purposes (for embankments or as road subgrade) or sent to landfill.
248
During the year 2009, a water volume of 69,830,735 m3 was produced by the plant and
introduced into the network for its delivering to the about 500,000 citizens which it reaches.
Since the year 1998, Publiacqua has been also making a noteworthy effort to promote the
utilization of public network water for drinking purpose, through the installation of public
fountains delivering free of charge improved quality water to the citizens. Here water is
further treated in a little refinement plant with the aim to improve its quality which could be
subject to worsening within the distribution network, especially from the organoleptic point of
view. Ten distribution points are currently present in the only municipality of Florence while
other seven are installed in the rest of the territory managed by Publiacqua. Their realization
can benefit of the subsidies foreseen in the framework of waste reduction policies.
The refinement system was initially based only on the sequence of activated carbon and
membrane filtration, in particular ultra-filtration (UF) on a tubular membrane with a cut-off
diameter of 50,000 Dalton. Water was finally stored in one accumulation tank with a capacity
of 1 m3. The unique system of this typology in function until the year 2004 was placed in the
Anconella Park and was named AQ_99. It was characterized by an high productivity (1,500
l/h), but about 30% of the treated water was discharged during filtration as retentate.
Moreover it necessitated of 1 day of stop per week to allow its sanitization through the
circulation of a sodium hypochlorite solution, and of wide spaces for its positioning especially
because of the presence of the water tank.
The treatment technology has been improved during the years, leading to the currently
employed H2O PLUS system which is the typology of plant installed since the year 2004. It is
able to deliver a continuous flow rate of 500 l/h and is characterized by a layout as the one
schematically illustrated in figure 4.9. The single installations can however differ in some
details.
249
Figure 4.9: Layout of the H2O PLUS water refinement system (Adapted from Rossi (2007))
As it can be observed, the system is based on a series of sequential treatments which begin
with activated carbon filtration to achieve the complete de-chlorination of water, the
adsorption of possible residual organic substances and the further improvement of its
organoleptic characteristics. The filter has a volume of 30 dm3 and a contact time (tc) of 15
minutes. It follows a further filtration on a polyether sulphone (PES) spiral membrane with a
molecular cut-off of 20,000 Dalton (ultra-filtration) and a filtration surface of 8 m2, to remove
residual suspended substances up to the dimensions of light organic compounds, and to
improve the efficiency of the successive UV disinfection stage. The membrane is protected by
a 5µm polypropylene pre-filtering cartridge which allows the removal of possible coarse
particulate substances which could cause membrane pores occlusion. The successive step of
UV rays disinfection allows to avoid the utilisation of chemicals and the related problems of
by-products formation with subsequent worsening of water organoleptic quality. One UV
lamp with a radiating dose of 40,000 mWs/cm2 is employed for the purpose. A last passage of
water through one absolute filter11 with a cut-off diameter of 0.2 µm is finally performed to
obtain a practically complete removal of the microbial load. The filter acts indeed as a
selective barrier against all those microorganisms which could have exceeded all the previous
devices.
11
An absolute filter is a filter capable of cutting off 100% by weight of solid particles greater than a stated size
in µm (Dictionary of Military and Associated terms – DOD).
250
The incoming water is refrigerated at the temperature of 14°C through a refrigerator of the
power of 3 kW able to provide a thermal jump of 10°C. This in order to avoid bacterial
growing into activated carbon filters and into the other components of the system, other than
making water more pleasant to the users.
Treated water is automatically re-circulated after a certain period of system inactivity in order
to avoid any type of stagnation and potential bacterial growing. Moreover, every 15 days,
system devices are sanitized through the circulation of a sodium hypochlorite solution, which
implies the stopping of the system itself for about half a day.
Consumable components of the system require the following substitution intervals:

activated carbon filter: every 6 months;

polypropylene pre-filtering cartridge: every 2 months;

UF membrane: every 2 years;

UV lamp: every year;

absolute filter: every 2 years.
The absence of the accumulation tank gives the system a greater compactness and therefore a
lower necessity of space for its installation with respect to the previous AQ_99system. This
also involve lower hygienic safety problems which could have been associated with water
stagnation into the tank itself. Moreover, a lower amount of water is rejected during
membrane filtration, involving an overall reduction of the respective consumptions. An
efficiency of about 90% can be indeed estimated.
The system is conceived for the treatment and the refining of water intended for human
consumption. Therefore the quality parameters of the incoming water will have to respect the
minimal requirements reported into the Annex 1 of the Legislative Decree number 31 of 2
February 2001. In this condition the system is able to assure:

a reduction of the total organic substance (in terms of TOC) of at least 80%;

a reduction of suspended solids (as TSS) of at least 90%;

the achievement and the maintaining of microbiological purity and

a total de-chlorination of water.
All this factors lead to an overall improvement of the organoleptic characteristics of the
treated water (taste, smell) and therefore of its pleasantness. As pointed out in paragraph 1.5,
the delivering of water with unpleasant smell or taste or with the presence of solid residues is
indeed the main reason that the majority of people adduce to justify the consumption of
bottled water (Temporelli and Cassinelli, 2005).
251
It is also worth to notice that, by operating with ultra-filtration, the system does not modify
the saline content of water because of its inability to remove ionic fractions. Thing that on the
contrary happens when reverse osmosis is utilized, how in the case of the domestic depurators
considered in the previous tap water scenario.
A system able to provide carbonated water (H2O GAS) was also more recently developed. It
is a simplified version of the H2O PLUS system and encompasses only a micro-filtration
(MF) and an UV rays disinfection stage, beyond refrigeration and CO2 addition. For this
reason it is more suitable to be employed on network fed by groundwater sources. Anyway it
is under study the implementation of the CO2 addition system also on the H2O PLUS one
(H2O PLUS-GAS), to go beyond this limitation.
Weak points of these systems are recognized to be, at least for the moment, the very high
realization, maintenance and analytical control costs. The first can vary between 15,000 € and
17,000 € according to the installation option (brickwork or steel case), while maintenance and
analytical control costs amount respectively to about 3,500 €/year and 2,000 €/year.
An environmental drawback deriving from the utilisation of such a typology of delivering
system could be associated to the trip of the citizens between their houses and public
fountains which could also be carried out through the use of a private car. Drinking of water
drawn directly from the tap does not imply instead this potential additional burden.
System boundaries
The inventory first of all includes all the life cycle processes required to model energetic and
raw materials consumptions associated with water purification and delivering, as well as
sludge disposal. The infrastructures involved in the supplying of the service are instead not
investigated because according to a preliminary evaluation of the tap groundwater system,
they are recognized to give a negligible contribution to the impact indicators considered in
this study. Infrastructures are therefore assumed to be the same of the tap groundwater
scenario only to allow a fair comparison between the two public network water scenarios.
The most important burdens associated with the delivering of improved quality water from
public fountains are also considered, as well as the life cycle of reusable bottles employed to
conserve water. The possibility of the utilisation of a private car for the round trip between
consumer house and the public fountain is also considered in order to highlight to which
extent consumers behaviour could influence the environmental performances of the present
scenario. Further details concerning this last two points will be given forth in the inventory.
252
The processes that on the basis of the inventory which is going to be carried out in this
paragraph, will be included in the present scenario, are graphically represented in figure D.5.
Reference flow
Coherently with the previous scenarios, the reference flow of this inventory is “1 litre of
improved quality water delivered to the consumers from public fountains and its further
consumption”. All inputs and outputs to and from the system are therefore related to this flow.
Data source
Data concerning the major inputs and outputs to and from the drinking water plant are
primary and directly provided by Publiacqua as well as the information pertaining to the
technical features of the H2O PLUS systems. Data employed to model energy generation and
raw materials production are instead taken from the Ecoinvent database, from the literature or
directly provided by manufacturers, as will be specified within the detailed inventory.
Detailed inventory
Natural resources consumptions
As for the case of Metropolitana Milanese, the main natural resource consumption directly
associated with drinking water delivering regards water itself. In particular, in view of the
69,830,735 m3 of purified water produced by the plant during 2009, 73,322,271 m3 are
estimated to be actually withdrawn from the Arno river. The difference between these two
values is associated with the volume of water employed for filters backwashing and with the
water content of clarification sludge. Water utilised for backwashing is the one outgoing from
the respective filtration stage and for this reason it should takes all the impacts associated with
its treatment till that stage. Anyway, since it was not possible to quantify separately the two
contributions, also backwashing water was modelled as a natural resource (Water, river). A
further important factor are network losses, whose amount is unfortunately unknown with
regard to the territory served by the plant. For this reason the same percentage of losses (about
11%) considered for the case of Milan is employed also for the present case. It must be
noticed that this is a very optimistic value if considering that the Italian average amounted to
253
30.1% during 2007, with the peak of 50.3% of the Apulian Aqueduct (Acquedotto Pugliese)
(Metropolitana Milanese, 2010).
On the basis of these considerations, the volume of water actually delivered to users can be
estimated to be:
Vwater delivered  69,830,735 m 3  (1  0.11)  62,149,354 m 3 ,
while the volume required to deliver 1 litre of water to users is therefore equal to:
Vwater 
73,322,271 m 3
 1.18 litres/lit re
62,149,354 m 3
Energy consumptions
The quantity of electricity utilised by the plant during the year 2009 amounts to 23,775,615
kWh, of which about 13,000,000 kWh (54.7%) are estimated by Publiacqua to be ascribable
to pumping of water into the network. The specific consumption can therefore be calculated
as:
Ee cons 
23,775,615 kWh/year
62,149,354  103 litres/yea r
Thermal energy is instead not required for plant operations.
How it can be noticed the specific consumption of electricity results to be lower than the one
characterizing the groundwater system (0.000485 kWh/l). This probably because a centralized
treatment, as that carried out at the Anconella plant, and the subsequent introduction into the
network by utilising a single pumping station, are less energy intensive than the utilisation of
single separated treatment stations each one equipped with a proper pumping group, even if a
less intense treatment is performed.
The Ecoinvent dataset Electricity, medium voltage, at grid/IT is employed to model the
burdens associated with electricity generation.
254
Material consumptions
Main materials consumptions are represented by chemicals employed in the various sections
of the plant, by filters activated carbon and quartziferous sand.

Chlorine dioxide (ClO2)
Chlorine dioxide is a yellow-greenish gas at ambient temperature which performs its
disinfecting action by oxidation. It cannot be compressed, liquefied and shipped as such
because of its unstable nature, which makes it explosive at air concentration of only 10 vol.%,
by rapidly decomposing to elemental chlorine and oxygen. For this reason it has to be directly
generated at the place of use with processes which, in the case of small scale applications, are
based on the oxidation of sodium chlorite (NaClO2 ) (EPA, 1999; Vogt et al., 2000).
In particular, nearby the Anconella plant, the following acid activation reaction between
sodium chlorite and hydrochloric acid (HCl) is utilised:
5 NaClO 2  4 HCl  4 ClO 2(g)  5 NaCl  2 H 2 O
The gas is firstly generated by mixing the two reagent solutions into a suitable reactor, to be
finally solubilised into the water stream.
The amount and typology of reagent solutions utilised at the plant for chlorine dioxide
generation during the year 2009 are reported in table 4.42 together with the respective
consumptions in relation to the reference flow, calculated by dividing the mentioned values
by the total volume of water delivered during the same year (62,149,354×103 litres).
Table 4.42: Consumptions of reagents for chlorine dioxide generation at the Anconella plant
Reagent solution
Hydrochloric acid (HCl)
33% (m/m) solution
Sodium chlorite (NaClO2)
25% (m/m) solution
Consumption
(kg)
Specific consumption
(kg/litre)
1,191,200
1.92×10-5
1,046,640
1.68×10-5
Hydrochloric acid production is modelled with the Ecoinvent dataset Hydrochloric acid, 30%
in H2O, at plant/RER which assumes that its generation takes place for 50% from the
combustion of hydrogen and chlorine and for the remaining 50% as a co-product from the
255
manufacturing of sodium sulphate. In this last case reagents consumptions associated with the
overall process are allocated to hydrochloric acid on a mass basis, while the remaining
process burdens are allocated on the basis of the economic value of the two co-products.
With regard to sodium chlorite manufacturing no life cycle data are instead provided in the
available databases and therefore raw materials consumptions associated with its production
are calculated on the basis of the stoichiometry of the reaction utilised for its generation at
industrial level.
Sodium chlorite is industrially manufactured through the absorption of chlorine dioxide gas
into a cooled (15-20°C) circulating solution containing sodium hydroxide (NaOH) and
hydrogen peroxide (H2O2), according to the reaction:
2 ClO 2  2 NaOH  H 2 O 2  2 NaClO 2  2 H 2 O  O 2
In particular hydrogen peroxide behaves as a reducing agent employed for the instantaneous
reduction of sodium chlorate that is generated together with sodium chlorite when chlorine
dioxide disproportionates by reacting with sodium hydroxide:
2 ClO 2  2 NaOH  NaClO 2  NaClO 3  H 2 O
An excess of hydrogen peroxide is therefore generally maintained into the solution in order to
avoid the occurring of this competing reaction as well as a small excess of sodium hydroxide
to stabilize the final sodium chlorite solution produced. A production yield of sodium chlorite
from the absorbed chlorine dioxide equal to 95% or better is generally achieved.
The product of the process is a 33% (m/m) solution of sodium chlorite which then can be
further diluted to a 25% solution, or converted to a dry solid product which is stabilized for
safety reasons, by the addition of i.e. sodium chloride, in order to decrease the sodium chlorite
content to 80% (m/m) of dry product (Madduri, 2007; ATSDR, 2004; Kaczur and Cawlfield,
2000; Vogt et al., 2000; IARC, 1991).
According to the reaction stoichiometry, and considering a production yield of 95% as
specified above, it is possible to calculate the amount of reagents required for the production
of 1 kg of pure sodium chlorite and of the 25% m/m commercial solution employed at the
plant. In particular reagents consumptions are defined by assuming that the whole amount of
water required to achieve the 25% titre is added at the end of the process, although it is also
256
partly generated during the reaction and partly provided by the reagents themselves. This last
contribution is indeed unknown. The results are summarised in table 4.43 together with the
modules employed to account for the burdens associated with reagents manufacturing and
utilised to build up the new module Sodium chlorite, 25% m/m solution, at plant, which
models the manufacturing of 1 kg of a 25% (m/m) sodium chlorite solution.
Table 4.43: Raw materials and energy consumptions attributed to the sodium chlorite manufacturing process
and employed to create the module “Sodium chlorite, 25% m/m solution, at plant”
Reagents (pure)/water
Amount
(kg/kg pure
(kg/kg 25%
NaClO2)
solution)
Chlorine dioxide (ClO2)
0.785
0.196
Sodium hydroxide (NaOH)
0.465
0.116
Hydrogen peroxide (H2O2)
0.198
0.0495
Demineralised water
Energy
Electricity
(kWh/kg sol.)
0
0.75
(Ecoinvent) module
Chlorine dioxide, from integrated
process, at plant1
Sodium hydroxide, 50% in H2O,
production mix, at plant/RER2
Hydrogen peroxide, 50% in H2O,
at plant/RER2
Water, deionised, at plant/kg/CH
Amount
Ecoinvent module
0.017
Electricity, medium voltage,
production UCTE, at grid/UCTE
Thermal energy – as steam
Heat, unspecific, in chemical
1.375
plant/RER
(MJ/kg/sol.)
(1) Built up on purpose as explained in the rest of the paragraph
(2) Module to be recalled with the required amount of pure substance
No available information was found with regard to process energy demands, but in order not
to neglect their contribution, these values are approximated with those of the sodium
hypochlorite production, available in the Ecoinvent database. This is assumed to be a
reasonable hypothesis if considering that both the mentioned chemicals are produced through
processes based on the same principle. Sodium hypochlorite is indeed manufactured by
introducing gaseous chlorine into a rings packed column where a sodium hydroxide solution
is circulating at a controlled temperature (30-35 °C) (Vogt et al., 2000). The amounts of
electrical and thermal energy considered are always reported in table 4.43.
Since the typology of fuel utilised for steam generation is unknown, the dataset employed to
model this process (Heat, unspecific, in chemical plant/RER) considers the average fuel mix
utilised for this purpose in the European chemical industry, according to the approach
described by Althaus et al. (2007) for chemicals inventoried in the Ecoinvent database.
257
Potential airborne and waterborne emissions are instead not considered in the inventory
because of data lacking. The only originated by-product is oxygen which leaves the reactor
without implying any environmental burden.
Chlorine dioxide employed in sodium chlorite production is in turn generated through the
chemical or electrochemical reduction of sodium chlorate under strong acidic conditions.
Chlorate-based methods are however mainly employed nearby pulp and paper mills for the
on-site generation of chlorine dioxide to be utilised as pulp bleacher, and about 95% of this
chemical is indeed produced for this purpose (Kaczur and Cawlfield, 2000; Vogt et al., 2000).
Several processes exist at present which mainly differ for the employed reducing agent, the
generated by-products, pressure conditions (vacuum or atmospheric processes) and
integration or less with production processes of feedstock materials. All of them are based on
the overall reaction:
chlorate  reducing agent  acid  chlorine dioxide  by - products
The reducing agents that may be used are methanol, sulphur dioxide, sodium chloride,
hydrochloric acid and most recently hydrogen peroxide. The choice of the acid is instead
limited to sulphuric and hydrochloric acid for practical, safety and economic reasons (Vogt et
al., 2000).
According to the same source, about 75% of the global production of chlorine dioxide for
bleaching purpose is carried out through methanol-based processes, while sulphur dioxide and
sodium chloride-based processes are loosing importance. The use of hydrogen peroxide as
reducing agent has been found to hold some advantages and to be a valid starting point for the
development of cleaner production methods (Qian et al., 2007). The use of hydrochloric acid
allows finally the utilisation of integrated processes, avoiding the need of transporting, storing
and handling large quantities of feedstock chemicals nearby pulp and paper mills.
No specific information are instead provided by the authors with regard to the technology
adopted for the generation of chlorine dioxide as a precursor for the industrial manufacturing
of sodium chlorite. We have however recognized that hydrochloric acid-based processes are
probably utilised for this purpose within integrated plants where also feedstock materials such
as chlorine (from a chlor-alkali process), sodium chlorate and hydrochloric acid are normally
produced. It seems indeed unlike that a stand alone plant, with the related needs of raw
258
materials, is settled for the manufacturing of the only amount of chlorine dioxide required for
chlorite generation, which is part of the 5% of product not employed for bleaching purposes.
These considerations are supported by the fact that the most important North American
producer of sodium chlorite, OxyChem, manufactures it within a plant where also sodium
hydroxide, chlorine and hydrochloric acid are produced (OxyChem, 2010). The same
consideration is valid for the ERCO Worldwide company, which also supplies sodium
chlorate (ERCO Worldwide, 2010).
For the present study we have therefore assumed that the integrated processes developed for
chlorine dioxide generation nearby pulp and paper mills, can well approximate the industrial
scale manufacturing process of this substance nearby chemical plants, for which no data are
available. In particular, reliable information and data are found concerning the technology
developed by Aker Solutions (Aker Solutions, 2010; Barr et al., 2009) and are utilised for the
following description of the process together with the ones provided in Vogt et al. (2000)
about this generic typology of processes.
Integrated systems, whose simplified layout is represented in figure 4.10, are composed by
three areas aimed respectively at the production of the two intermediate products, sodium
chlorate and hydrochloric acid, and the final product, chlorine dioxide. Hydrochloric acid acts
also as reducing agent.
259
Chlorine (Cl2)
(from on site chlor-alkali plant
or purchased)
H2
NaOH
Demineralised
water
HCl
Synthesis
Cl2
H2
absorption
(weak chlorine)
HCl
Chilled
water
Excess H2
Electricity
NaClO3
production
NaClO3
(strong chlorate liquor)
ClO2
generation
ClO2
absorption
ClO2
solution
NaCl+NaClO3
(weak chlorate liquor)
Figure 4.10: Simplified layout of the process developed by Aker Solutions for the integrated generation of
chlorine dioxide (Adapted from Barr et al. (2009))
Chlorine dioxide gas is produced by combining sodium chlorate with hydrochloric acid into
the chlorine dioxide generator according to the overall reaction:
NaClO 3  2 HCl  ClO 2  0.5 Cl 2  NaCl  H 2 O
The mixture of chlorine dioxide and elemental chlorine gas generated in this way is absorbed
with cooled water and the resulting solution is further stripped with air to remove possible
residual chlorine. Not absorbed chlorine (weak chlorine) is recycled for hydrochloric acid
production. The residual liquor containing not reacted chlorate and the by-product sodium
chloride originated in the reactor, called weak chlorate liquor, is instead recycled for the
sodium chlorate production.
Sodium chlorate is generated by electrolysis of this recirculated sodium chloride (NaCl)
solution according to the overall reaction:
NaCl  3 H 2 O  Electricit y (6e - )  NaClO 3  3 H 2
260
The products are a strong chlorate liquor, which is fed to the chlorine dioxide generator, and a
gaseous mixture of hydrogen and small amounts of chlorine which is used as feedstock for
hydrochloric acid production. The gaseous stream exceeding the requirements of this last
process is instead absorbed in a packed tower with a sodium hydroxide solution in order to
remove chlorine and is then released to the atmosphere. Sodium hypochlorite and sodium
chloride are generated in this process.
Hydrochloric acid is finally produced by the combustion of hydrogen and chlorine gases into
a suitable synthesis unit, according to the following reaction:
H 2  Cl 2  2 HCl
Within the same synthesis unit, most of the generated gas is subsequently absorbed in
demineralised water to form a 32% (m/m) solution which is fed to the chlorine dioxide
section. Not directly solubilised hydrochloric acid is instead absorbed into a separated unit
whose absorption water is in turn utilised into the same HCl synthesis unit, optimising the
recovery level. Gas released from the separated unit are represented by the excess of hydrogen
supplied to assure the complete combustion of chlorine and inert gases, such as nitrogen,
which can be found in the fed chlorine gas.
Hydrogen supplied to the synthesis unit is the one generated in the sodium chlorate
electrolysis. Part of chlorine is supplied from the chlorine dioxide generator while the
remaining part of chlorine is instead produced from an on-site chlor-alkali plant or can be
purchased.
By combining the three reactions which take place in the system, it is possible to obtain the
overall reaction which corresponds to the following theoretical equation:
0.5 Cl 2  2 H 2 O  Electricit y  ClO 2  2 H 2
It is therefore possible to recognize how, once started up, the process only consumes chlorine,
water and electricity to generate chlorine dioxide.
It is possible however, that the levels of consumption which characterize these typologies of
processes differ from those associated with the industrial scale manufacturing of chlorine
dioxide nearby chemical plants. The fact that in this plants the single unit processes are not
only conceived for the supplying of feedstock materials to the chlorine dioxide cycle but also
261
for the industrial scale manufacturing of the respective intermediate product, could imply to
achieve lower level of integration and, therefore, higher consumptions.
In absence of specific information regarding these realities, life cycle data associated with the
described technology are however utilised to model chlorine dioxide production in the present
study.
The new module Chlorine dioxide, from integrated process, at plant is therefore established
to model the manufacturing of 1 tonne of pure chlorine dioxide, on the basis of the data
concerning main raw materials and energy consumptions reported by Barr et al. (2009) for the
Aker Solutions process and by Vogt et al (2000) for a generic integrated process. These
values, as well as those considered in this study, are reported in table 4.44 together with the
Ecoinvent modules employed to account for the burdens associated with the life cycle of the
respective inputs.
Table 4.44: Raw materials and energy consumptions associated with the integrated manufacturing process of
chlorine dioxide and employed to create the module “Chlorine dioxide, from integrated process, at plant”
Barr et al.
(2009)
-Aker
Solutions
process-
Amount
Vogt et al.
(2000)
-Generic
integrated
process-
kg/t ClO2
730
730
730
kg/t ClO2
15
-
15
m3n/t ClO2
0.46
-
0.46
Cooling water
m3/t ClO2
1,200
-
1,200
Chilled water
(for ClO2 absorption)
m3/t ClO2
140
-
-
Demineralised water
(for H2 absorption)
Energy
Electricity
(for electrolysis)
Electricity
(other consumptions)
m3/t ClO2
5
-
5
Material
Chlorine (reagent)
Sodium hydroxide
(NaOH, for Cl2
absorption)
Nitrogen gas
(for circuits purging)
Unit
Unit
kWh/t ClO2
Amount
250
Ecoinvent module
Chlorine, liquid, production
mix, at plant/RER
Sodium hydroxide, 50% in
H2O, production mix, at
plant/RER(1)
Nitrogen, liquid, at plant/RER
Water, cooling, unspecified
natural origin/m3(2)
Not included: chlorine
dioxide is not absorbed in
water but directly in the
caustic solution (see text)
Water, deionised, at
plant/kg/CH
Ecoinvent module
9,000
8,900
kWh/t ClO2
This
study
9,250
Electricity, medium voltage,
production UCTE, at
grid/UCTE
kg/t ClO2
7,000
8,000
8,000
Heat, unspecific,
in chemical plant/RER
(MJ/t ClO2)3
(17,500)
(22,000)
(22,000)
(1) Module to be recalled with the required amount of pure substance
(2) Modelled as natural resource without assigning any production burden
(3) The value in kg is converted in MJ by considering a steam heat content of 2.75 MJ/kg, as explained in the
text
Steam
262
Some details concerning the most important performed choices and if necessary, the reasons
they are based on, will be now briefly described.
The dataset chosen to model chlorine production accounts for the burdens associated with the
generation of liquid chlorine through the average European mix of the different typologies of
electrolytic cells utilised for the chlor-alkali process: mercury, diaphragm and membrane
cells. In this dataset the burdens of the chlor-alkali process are assigned on the basis of the
mass of each substance generated in the process itself and in particular 46.4% of these are
assigned to chlorine production. In the case in which chlorine is produced on-site, as probably
happens in the plants under investigation, the liquefaction process would not be required but
its burdens are however left included according to a conservative approach.
As done by Althaus et al. (2007) for the chemicals inventoried in the Ecoinvent database, the
mass of steam consumed by the process is converted to energy (MJ) by considering that it is
supplied at the pressure of 4 bar and at the temperature of 150°C. In these conditions
superheated steam has an heat content (specific enthalpy) of about 2.75 MJ/kg. The dataset
employed to model steam production is the same also utilised for sodium chlorite, according
to the already explained reasons.
Electricity and water consumptions reported in table 4.44 also include the amounts employed
for absorbing chlorine dioxide gas and for stripping residual chlorine from the generated
solution. This is generally made in order to obtain a highly pure chlorine dioxide solution to
be employed for ECF (Elementary Chlorine Free) pulp bleaching processes. In the case in
which the process is aimed at sodium chlorite manufacturing, chlorine dioxide gas is expected
not to be absorbed with chilled water but directly into the caustic solution of sodium
hydroxide and hydrogen peroxide. Also the stripping stage is expected not to be made as well.
For these reasons, the amount of chilled water consumed by the integrated plant is excluded in
this inventory while, since it has not been possible to disaggregate energetic consumptions,
the whole amount reported is however considered.
The concentration of residual chlorine into the generated chlorine dioxide solution is a weak
point of integrated processes, for which values of about 0.2-0.24 g/l are achieved if chlorine
stripping is carried out (Aker solutions, 2010; Vogt et al., 2000). If this is not made,
concentrations of about 0.9-1.9 g/l can be expected (Vogt et al, 2000; Stockburger 1993). Not
chloride-based processes can instead reach levels of 0.01 g/l (Vogt et al, 2000). In order to
achieve chlorine content comparable with this value, a stripping or an hydrogen peroxide
263
oxidation stage must be foreseen for chloride based processes (Vogt et al, 2000; Stockburger
1993).
The level of residual chlorine is of relevant importance also in products destined to water
treatment because of its potential contribution to the generation of toxic disinfection byproducts such as THMs (trihalomethanes) (EPA, 1999). Since chlorine dioxide is absorbed
with hydrogen peroxide to generate sodium chlorite, it can be expected that low
concentrations of residual chlorine are however achieved in the resulting chlorite solution,
despite air stripping is not performed.
No information about potential airborne and waterborne emissions are finally found with
regard to the integrated process. The former are however restricted to possible chlorine
emissions from the absorption of the mixture of excess hydrogen and chlorine originating
from chlorate electrolysis. They can be however assumed to be of negligible entity if
considering that the gaseous flow undergoes to efficient cleaning with sodium hydroxide.
No waterborne emissions appear instead to be potentially generated under normal operative
conditions as well as solid wastes. The main advantage of chloride-based process is indeed
the fact that the production and the handling of acidic effluent solutions or of solid salt cakes
is avoided (Barr et al., 2009; Vogt et al., 2000; Stockburger, 1993).

Polyaluminium chloride (PACl)
Polyaluminium chloride (PACl) is an inorganic polymer utilised for water clarification by
promoting flocculation and coagulation of suspended solids. It can be seen as the intermediate
product between aluminium hydroxide (Al(OH)3) and aluminium chloride (AlCl3) and can be
represented by the simplified formula:
(Al n (OH) m Cl 3n  m ) x
where 0 < m < 3n and x depends form the degree of polymerization and is approximately
equal to 15.
PACl is produced by reacting aluminium hydroxide (Al(OH)3, as trihydrated or hydrated
alumina) with hydrochloric acid in lower amount with respect to the stoichiometric, to
achieve the incomplete chlorination of the hydroxide (substitutions of hydroxyls with
chlorine), according to the simplified reaction
n Al(OH) 3  m HCl  Al n (OH) m Cl 3n m  m H 2 O
264
The level of chlorination (neutralization of hydroxyls) establishes the basicity of the product,
which is defined as the ratio between the number of charges of the hydroxyls group and those
of the aluminium atoms actually present in the obtained compound and is practically equal to
m/3n.
Products with high basicity, i.e. greater than 60% for the Anconella plant, are generally
employed for water treatment because, when dissolved in water, they hydrolyze originating
charged hydroxide flakes as much bigger as many hydroxils there are in the molecule. It is
just the generation of large and heavy flakes which, together with its employability in wide
pH range without consuming water alkalinity, makes the use of PACl advantageous with
respect to traditional aluminium and iron based coagulants.
Solutions with a 10% (m/m) titre as Al2O3 are traditionally employed for water clarification,
while those with a 18% titre are generally employed as auxiliaries in paper manufacturing
(SCIPE, 2010; Crittenden et al., 2005; UNI, 2004; Consito, 2003).
The amount of PACl solution (10% Al2O3 m/m, basicity>60%) consumed at the plant during
the year 2009 was of 4,473,875 kg which corresponds to a specific value of 7.2 ×10-5 kg/litre
in view of the total volume of water delivered during the same year (62,149,354×103 litres).
Because of the complexity of the reaction involved in PACl generation, the amount of
reagents required for this purpose are difficult to be derived from the respective
stoichiometry. They also depend from the basicity to be achieved in the final product which
defines the amount of acid needed to neutralize aluminium hydroxide. Raw materials and
energy consumptions are therefore quantified on the basis of the indications provided by one
producer of this substance (Calcatelli, 2010) and of literature data (Consito, 2010 and Solvay
Solexis, 2005).
According to Calcatelli (2010), the manufacturing process foresees that raw materials,
hydrochloric acid (HCl) as a 33% solution and aluminium hydroxide (as Al2O3×3H2O or
Al2O3×H2O) are firstly mixed in a preparer and then introduced into a reactor heated by steam
circulating into an adjacent jacket. At the end of the reaction the reactor is cooled with
demineralised water circulating through an heat exchanger where it cedes the acquired heat to
fresh filtered water. The product is then transferred to a cooled tank and filtered to remove
solid residues of not reacted raw materials. It is then moved in a temporary stocking tank,
265
diluted with demineralised water to achieve the desired titre and finally sent to the final
stocking tanks.
For the production of 1 lot of 18% PACl solution with an about 45% basicity, 4,650 kg of
hydrated alumina and 6,800 kg of HCl solution are introduced in the preparer. Considering
that 4 lots of about 70 tonnes are daily produced, the amount of reagents required to produce 1
tonne of polyaluminiun chloride can be therefore calculated as:
M Al 2O3 3H 2 O 
M HCl 
4,650 kg Al 2O3 3H 2O /lot
(70/4) t PACl /lot
 265.7 kg Al 2 O3 3H 2O /t PACl
6,800 kg HCl /lot
 388.6 kg HCl /t PACl
(70/4) t PACl /lot
Other data concerning raw materials and energy consumptions are also found in relation to the
unit process developed for PACl production by the company Consito, which is based on a
technology similar to the one described above (Consito, 2010; 2005). The data refers to the
production of a 18% solution with 40% basicity. Another considered data source is finally the
environmental report of the company Solvay Solexis in which reagents and energy
consumptions of the PACl productive cycle, registered for the years 1998-2004 (Solvay
Solexis, 2005) are also included. No information are provided in this case about the typology
of solution produced.
Data from these different sources are summarized in table 4.45 together with the values
chosen for this study and the Ecoinvent datasets utilised to model the burdens associated with
the life cycle of the various inputs and therefore also to built up the module Polyaluminium
chloride, 18% Al2O3 solution, at plant which models the production of 1 tonne of 18% Al2O3
PACl solution with an average 40%-45% basicity.
266
Table 4.45: Raw materials and energy consumptions associated with PACl solution manufacturing and
employed to create the module “Polyaluminium chloride, 18% Al2O3 solution, at plant”
Production of Polyaluminium chloride – 18% (m/m) solution as Al2O3, 40-45% basicity
Amount
Solvay
Calcatelli
Consito
Material
Unit
Ecoinvent module
This study
Solexis
(2010)
(2010)
(40% bas.)
1
45% bas.
40% bas.
(2005)
Aluminium
Aluminium
300-325
hydroxide
hydroxide, at
kg/tPACl
265.7
279
300
(58-62% of
(hydrated
plant/RER
Al2O3)
alumina)
Hydrochloric
acid – 32%
(m/m) solution
kg/tPACl
Cooling water
388.6
680-700
(32-33% sol.)
(31-33% sol.)
m3/tPACl
-
Compressed air
m3n/tPACl
-
Energy
Unit
Electricity
kWh/tPACl
(960)
700
15
-
15
16
-
16
Amount
-
35
Hydrochloric acid,
from the reaction of
hydrogen with
chlorine, at
plant/RER
Water, cooling,
unspecified natural
origin/m3(3)
Compressed air,
optimised generation,
<30kW, 12 bar
gauge, at
compressor/RER U
Ecoinvent module
49.9
35
Electricity, medium
voltage, production
UCTE, at grid/UCTE
kg/tPACl
250
Heat, unspecific, in
(MJ/tPACl)3
(711)
711
chemical plant/RER
4
Thermal energy
MJ/tPACl
220
(1) Data reported in the table refer to the year 2004
(2) Modelled as natural resource without assigning any production burden
(3) The mass of steam is converted to energy (MJ) considering that it is supplied at 7 bar (as specified) and 200
°C. In this conditions, steam has an heat content of 2.844 MJ/kg
(4) This value does not include the conversion efficiency as heat, how it is instead implicitly done for steam
Steam (7 bar)
Some indications are now given with regard to the most important performed choices.
First of all, the module employed to describe hydrochloric acid production considers its
generation from the reaction of hydrogen with chlorine because this is the process expected to
be actually used for the production of PACl for drinking water applications. The utilisation of
chlorine generated as by-product from other processes could be indeed expected to bring
higher level of impurities to the solution itself. Despite of this, it is worth to notice that in the
process described by Calcatelli (2010), hydrochloric acid is produced with by-product
chlorine originating from the synthesis of potassium sulphate, while Solvay Solexis utilises
chlorine deriving from hydro-chloro-floro-carbons (HCFC) productive cycles. In these cases
the burdens of the overall process should be allocated among the various generated coproducts.
267
The value concerning hydrochloric acid consumption derived by Solvay Solexis (2005) is
overestimated because it refers to the whole amount of substance generated as co-product of
the HCFC productive cycles, which is actually in part commercialized other than being
employed for PACl manufacturing. The value was therefore not considered.
The dataset employed to model compressed air generation foresees its supplying at 12 bar and
it is chosen because, among the available datasets, it is the one which assigns to the process
the worst performances with respect to the considered impact indicators.
Finally with regard to electricity consumptions, the value of 35 kWh was considered instead
of the maximum value of 49.9 kWh because in this last value the amount of energy required
for compressed air generation is indeed probably already included while its contribution was
separately considered in the module associated with compressed air generation. For reason of
coherence the first value was therefore considered.
The so established inventory models therefore the production of a solution with an average
40-45% basicity, while to reach the 60% basicity of the solution employed at the plant, a
lower amount of acid would have actually to be used for the same amount of aluminium
hydroxide to neutralize. Alternatively it would be possible to add a basifying compound such
as sodium carbonate to substitute the excess chlorine with hydroxyls. These potential
variations of consumptions are however neglected because of data lacking.
The amount of dilution water required to reach the 10% Al2O3 titre of the solution actually
employed is instead accounted for. It can be defined by considering that to generate 1 kg of
10% solution, which contains 0.1 kg of equivalent Al2O3, an amount of 18% solution equal to
0.1/0.18=0.56 kg has to be diluted with (1-0.56)=0.44 kg of demineralised water.
According to these considerations the module Polyaluminium chloride, 10% Al2O3 solution,
at plant is established to model the production of 1 tonne of 10% Al2 O3 PACl solution,
starting form 560 kg of 18% solution and 440 kg of demineralised water, as summarized in
table 4.46.
Table 4.46: Raw materials associated with 10% Al2O3 PACl solutions production and employed to create the
module “Polyaluminium chloride, 10% Al2O3 solution, at plant”
Production of Polyaluminium chloride – 10% (m/m) solution as Al2O3, 40-45% basicity
Material
Amount (kg/tsolution)
Module
Polyaluminium Chloride, 18%
Polyaluminium chloride, 18%
560
Al2O3 solution, at plant
(m/m) Al2O3 solution
Water, deionised, at plant/kg/CH
Demineralised water
440
268

Sodium hypochlorite is utilised at the plant as a solution with a titre of 15% (m/v) as active
chlorine and its consumption registered in 2009 was of 713,320 kg. Considering that a
solution density of 1.23 kg/litre is required in the specifications, it is possible to calculate the
amount consumed of pure substance as:
M NaClO  713,320 kg sol 
0.15kg Cl 2 /l sol. 74 kg NaClO

 90,666 kg NaClO
1.23 kg sol/l sol.
71 kg Cl 2
In view of the 62,149,354×103 litres delivered to the users, the specific consumptions of
solution and of active substance are therefore equal to 1.15×10-5 kg/litre and 1.46×10-6 kg/litre
respectively. The burdens associated with the manufacturing of sodium chlorite are modelled
with the Ecoinvent dataset Sodium hypochlorite, 15% in H2O, at plant/RER which considers
its production from the reaction of sodium hydroxide and chlorine. This last is assumed to be
a by-product from other processes and therefore does not carry any burdens in the system.

Potable Water Grade (PWG) Polyelectrolyte
Organic polyelectrolytes are employed at the plant for sludge conditioning and, in particular
conditions also as clarification auxiliaries. Of the total amount annually consumed, about 90%
is of anionic nature and only the remaining 10% of cationic nature. The former is employed in
correspondence of the thickeners to improve sludge settling rate, while the latter nearby filterpresses to improve their dehydration. Of the various available physical forms, the powdered
one is employed at the plant.
According to SNF FLOERGER (2006; 2005; 2002) polyelectrolytes employed as flocculants
are hydrophilic polymers of high molecular weight and with a degree of polymerization
between 14,000 and 420,000 monomer units. They are usually based on acrylamide
monomers and can be of non ionic, cationic or anionic nature as a function of the fact that
they are co-polymerized or less with charged species. For these reasons they are also pointed
out with the name of non ionic, anionic or cationic polyacrylamides. Cationic and anionic
polyelectrolytes are water soluble thanks to the polarity of the functional groups they contain,
so that the various segments of a chain are dissociated in water, bringing anionic or cationic
charges to the medium they are introduced in.
269
Non-ionic polyelectrolytes are acrylamide homopolymers (polyacrylamides) obtained from
the polymerization of only acrylamide monomers (figure 4.11). A slight hydrolysis of the
amidic group however gives them a slight anionic nature.
Figure 4.11: Generation and structure of non ionic polyacrylamide (Adapted from SNF FLOERGER (2005))
Anionic polyelectrolytes are instead generally obtained from the copolymerizarion of
acrylamide and sodium acrylate, deriving from the reaction of acrylic acid with sodium
hydroxide (figure 4.12).
Their anionicity can vary between 0% (polyacrylamide) and 100% as a function of the ratio in
which the different monomers are involved in, which in turn depends from the nature of the
medium to be treated.
Figure 4.12: Generation and structure of anionic polyacrylamide (Adapted from SNF FLOERGER (2002))
Finally, cationic polyelectrolytes are mainly derived from the copolymerization of acrylamide
with a chlorometilated monomer such as chloro metilated dimethyl-amino-ethyl acrylate
(Methyl Chloride-ADAM) or chlorometilated dimethyl-amino-ethyl methacrylate (Methyl
Chloride -MADAM) (figure 4.13). Also in this case the cationic charge of the copolymer can
vary between 0% (polyacrylamide) and 100% as a function of the ratio of each monomer in
the final product which in turn depends from the nature of the medium to be treated.
270
Figure 4.13: Generation and structure of cationic polyacrylamide (Adapted from SNF FLOERGER (2002))
The total amount of powdered polyeclectrolyte consumed at the plant during the year 2009
was of about 20,000 kg which, in view of the 62,149,354×103 litres delivered to the users,
corresponds to a specific value of 3.22 ×10-7 kg/litre.
Detailed data concerning the amount of raw materials required for polyelectrolites synthesis
as well as the other involved environmental burdens were unfortunately not made available.
Raw materials consumptions will also depend from the density of charge of the product,
according to the previous considerations.
For this reason the life cycle of polyelectolytes is modelled by only considering the burdens
associated with the manufacturing of acrylamide monomers which can be approximately
considered to be the main components of these polymeric compounds.
According to Habermann (2002) acrylamide is generally manufactured through the
chemically or biologically catalyzed hydrolysis of acrylonitrile. On this basis, we have
decided to model acrylamide production with that of this precursor through the Ecoinvent
dataset Acrylonitrile, at plant/RER. No modules concerning acrylamide production are indeed
established in the available databases and no further information are found.

Quartiferous sand
The mass of quartziferous sand installed at the plant can be calculated by remembering that
the 18 filters of the first line have a total filtering surface of 1,080 m2 (60 m2 each one) for a
bed height of 0.9 m, while the 12 of the second line have a total surface of 1,800 m2 (150 m2
271
each one) for a bed height of 1 m. Considering then a sand density equal to the average
density of quartz12 (2,650 kg/m3) it is possible to obtain:
M sand  [(1,080  0.9) m 3  1,800 m 3 ]  2,650 kg/m 3  7,345,800 kg
The amount of sand required to deliver 1 litre of water can be therefore defined by
considering that the average life of the sand at the plant is of about 10 years. This value is
estimated by the company on the basis of the average amount of sand annually employed to
restore the volume lost during the ordinary functioning of the plant and during filters
backwashing.
M spec_sand 
7,345,800 kg
 1.18  10 5 kg/litre
62,149,354  10 3 litres/yea r  10 years
Preparation of sand is modelled with the Ecoinvent dataset Silica sand, at plant/DE, which
account for the burdens associated with sand and gravel mining, rounding, sizing, washing
and dewatering.
Sand is never substituted and subsequently disposed of but only reintegrated, therefore no end
of life treatment has to be modelled with regard to its life cycle.

Activated carbon
The mass of activated carbon employed at the plant can be calculated by remembering that the
14 filters there installed have a filtering surface of 130.4 m2 and a bed height of 2.2 m each
one. A total volume of 4,016 m3 can be therefore calculated, which corresponds to a total
mass of 2,008 tonnes if a carbon bulk density of 500 kg/m3 is conservatively considered.
Mineral carbons have indeed a bulk density ranging between 400 and 500 kg/m3 (SICAV,
2010). At the end of its useful life span, which for the typology of water treated by the plant is
estimated to be equal to about 3 years, activated carbon is sent to reactivation in external
plants where it is recovered with an average 88% efficiency.
12
Contract specifications do not impose any restriction on sand density but rather on its granulometry. Sand
density can be however well approximated with that of quartz which is encompassed between 2,600 and 2,700
kg/m3.
272
The amount of carbon required to deliver 1 litre of water can be therefore calculated as
follow:
M spec_GAC
2,008  10 3 t

 1.08  10 5 kg/litre
3
62,149,354  10 litres/yea r  3 years
Activated carbon life cycle can be modelled as a case of closed loop recycling, as showed in
figure 4.14, analogously to as done in paragraph 4.8.1 for the tap groundwater scenario.
Activated carbon
production
(1-0.88)×(1.08×10-5)= 1.29×10-6 kg/litre
Activated carbon
utilization
0.88×(1.08×10-5)=9.48×10-6 kg/litre
1.08×10-5 kg/litre
Activated carbon
reactivation
Losses (aeriforms)
1.29×10-6 kg/litre
Figure 4.14: Conceptual model of the life cycle of the activated carbon utilised at the Anconella plant as a case
of closed-loop recycling
The processes that have to be considered to model activated carbon life cycle are therefore:

production of 1.29×10-6 kg of virgin activated carbon and

reactivation of 1.08×10-5 kg/litre of exhausted carbon.
As for the tap groundwater scenario (paragraph 4.8.1) a module built up with data provided in
the ANPA I-LCA database (ANPA, 2000) concerning the production of carbon coke is
employed to approximate activated carbon manufacturing, while the module Exhausted
carbon reactivation already created and described in paragraph 4.8.1, is utilised again in this
scenario to model carbon reactivation.
273
No powdered activated carbon (PAC) consumptions were finally registered during 2009.
They depend indeed from the quality of the incoming water, that did not required this
typology of treatment during the year assumed as reference.
Only the supernatant originating from sludge thickener basins constitutes wastewater, because
water utilised for filters backwashing is reintroduced at the head of the plant. Supernatant is
directly discharged into the Arno river but no information with regard to its amount and
quality were available. No waterborne emissions were therefore assigned to the system.
Airborne emissions
Ozone emissions could potentially originates from the ozonization process, but no
information were available in their respect. They are however expected to be of negligible
entity in view of the fact that this typology of treatment is generally carried out in a closed
system. No airborne emissions were therefore assigned to system.
Waste generation
The major waste stream originating at the plant is represented by clarification sludge. In
particular 10,821,640 kg of sludge were generated during the year 2009 which correspond to a
specific production of 1.74 ×10-4 kg/litre, calculated as usual.
A meaningful fraction of them (around 90%) is however utilised for further applications such
as, for instance, as material for embankments or as road subgrade and only the remaining 10%
is disposed of in landfill. Therefore only the burdens associated with the landfilling of
1.74×10-4 × 0.1=1.74 ×10-5 kg of sludge are accounted for and, in particular, the Ecoinvent
dataset Disposal, inert waste, 5% water, to inert material landfill/CH is employed for its
modelling. According to a conservative approach no compensative processes are instead
credited to the system with regard to the amount of sludge utilised for further purposes. This
also in view of the high uncertainty associated with establishing which kind of processes are
actually potentially avoided as consequence of their utilisation.
274
Burdens associated with plant infrastructures are not quantified because a preliminary
evaluation of the groundwater system has revealed their very marginal contribution on the
overall results. The processes already defined for this system are however fictitiously
included to allow a fair comparison between the two public network water scenarios.
Table 4.47 summarises for clarity the overall inputs and outputs of energy and materials to
and from the Anconella drinking water treatment plant as well as the SimaPro datasets
employed to build up the module Tap water, at user, from surface origin which, on the basis
of all the processes described till now, models the purification and the delivering of 1 litre of
water to a domestic user or to a public fountain.
Table 4.47: Major energy and materials inputs and outputs to and from the Anconella drinking water treatment
plant
l
Absolute
value
73,322,2712
kWh
23,775,615
0.000382
Hydrochloric acid (HCl) - 33% m/m sol.
(HCl – pure substance)
kg
1,191,200
(393,096)
1.92×10-5
(6.33×10-6)
Sodium chlorite (NaClO2) - 25% m/m sol.
kg
1,046,640
1.68×10-5
kg
4,473,875
7.2×10-5
713,320
1.15×10-5
(90,666)
20,000
7,345,800
(1.46×10-6)
3.22 ×10-7
1.18×10-5
1.08×10-5
1.29×10-6
9.48×10-6(3)
1.74 ×10-4
1.74 ×10-5
Material/Energy
Water
Electricity
Polyaluminium chloride (PACl) 10% as Al2O3 m/m sol.
Sodium Hypochlorite (NaClO) 15% (m/v) as active Cl sol.,
(NaClO – pure substance)
PWG Polyelectrolyte
Quartziferous sand
Unit
Unit/litre
SimaPro Module1
1.182
Water, river
Electricity,medium
voltage, at grid/IT
Hydrochloric acid, 30%
Sodium chlorite, 25% m/m
solution, at plant
Polyaluminium chloride,
10%Al2O3 solution, at plant
kg
kg
kg
Activated carbon (GAC) - total
 modelled as virgin production
 modelled as reactivated
kg
2,008,000
240,960
1,767,040(3)
Sludge – total
 to landfill
kg
10,821,640
1,082,164
Sodium hypochlorite, 15%
Acrylonitrile, at plant/RER
Silica sand, at plant/DE
 Carbon coke
 Exhausted carbon
reactivation
Disposal, inert waste, 5%
water, to inert material
landfill/CH
(2) The absolute amount of water reported is the one actually consumed by the plant while the specific amount is
calculated by estimating network losses
(3) In order to obtain 9.48×10-6 kg of reactivated carbon, 1.08×10-5 kg have to be sent to reactivation and the
respective module has to be recalled with this amount
275
Water quality improvement and delivering from public fountains
As previously described, in this scenario the use of a domestic depurator is replaced with that
of public fountains able to deliver refined high quality water to the citizens. In particular the
H2O PLUS system developed by Publiacqua is just assumed as the technology of reference
and the most important burdens associated with this practice are included in the system, on
the basis of the information provided.
First of all, water consumptions can be estimated by considering that, according to the
information provided, about 60 m3/month of water are delivered on average by the installed
systems, in view of 65 m3/month actually drawn from the network. This means that in order to
supply 1 litre of water, 65/60=1.08 litres are actually utilised, corresponding to an average
efficiency of about 92%.
The possible consumptions of water for the periodical sanitization are indeed not known. The
module earlier established (Tap Water, at user, from surface origin) is employed to model
water consumptions.
The H2O PLUS systems have an overall installed power of about 5 kW of which 3 kW of the
only refrigerator plant. Assuming that such a power is the same of the absorbed one and
considering that the deliverable flow rate is of 500 l/h, the amount of electricity required to
supply 1 litre of refrigerated water can be roughly estimated as:
Ee fountain 
5kW
 0.01 kWh/litre
500 l/h
From this value is excluded the consumption associated with the circulation of the
hypochlorite solutions during the periodical sanitization. It is however expected to have a
marginal contribution with respect to the one associated with water supplying. The dataset
employed to model electricity generation is the same utilised for the plant (Electricity,
medium voltage, at grid/IT).
With regard to the consumptions of consumable materials, it has been possible to quantify
only those associated with the periodical substitution of the polypropylene pre-filtering
276
cartridge and of the activated carbon filter. They are however the elements substituted with
the higher frequency (every 2 and every 6 months respectively) while the remaining are
substituted with annual frequency (UV lamp) or every 2 years (membrane and absolute filter).
The pre-filtering cartridge has an overall volume of about 2 litres and is replaced every two
months. Assuming for simplicity that the filters is constituted by an homogeneous mass of
polypropylene, considering that this material has a density of around 900 kg/m3 and that about
60,000 litres per month are on average delivered by the systems placed in the municipality of
Florence, it is possible to calculate the mass of polypropylene required to deliver 1 litre of
improved quality water as:
M PP fountain 
2  10 3 m 3  900 kg/m 3
 1.5  10 5 kg/litre
60,000 l/month  2 months
It is worth to notice how performing such an estimate on the basis of the maximum
deliverable flow rate of 500 l/h would be misleading because the systems do not operate in
continuous.
To model virgin polypropylene production the Ecoinvent dataset Polypropylene, granulate, at
plant/RER is employed and the material is assumed to undergo extrusion for the
manufacturing of the pre-filter, process modelled through the Ecoinvent dataset Extrusion
plastic film/RER. As specified in the database a conversion efficiency of 97.6% is considered
in carrying out the modelling. At the end of its useful life, the pre-filter is assumed to be
incinerated, process modelled through the Plastic incineration dataset already described in
paragraph 3.3.3.
The activated carbon filter has a volume of 30 dm3 and is replaced every 6 months.
Remembering that about 60,000 litres per year are assumed to be delivered on average by the
system and considering a carbon bulk density of 500 kg/m3 (SICAV, 2010), the amount of
activated carbon required to deliver 1 litre of water can be estimated as:
M GAC fountain 
30  10 3 m 3  500 kg/m 3
 4.17  10 5 kg/litre
60,000 l/month  6 months
277
The same module considered in the case of the plant is employed again to model the
manufacturing of this amount of carbon which is assumed to be disposed of in landfill at the
end of its useful life, process modelled with the already utilised dataset Disposal, inert waste,
5% water, to inert material landfill/CH.
The burdens of the treatment at wastewaters treatment plant of the volume of water rejected
by the system (about 0.08 litres/litre), which is assumed to be a substantially unpolluted
sewage, are finally considered. The module employed for this purpose is Treatment, sewage,
unpolluted, to wastewater treatment, class 3/CH.
No information were instead provided with regard to the consumptions of others consumable
materials such as membrane, absolute filter and sodium hypochlorite for the periodical
sanitization of the system.
The burdens associated with the life cycle of system infrastructure materials are not included
because the respective burdens are averaged on their whole life span and are considered to be
of secondary importance.
Table 4.48 summarises the consumptions attributed to the process of delivering of improved
quality water from public fountains thanks to the treatment trough the H2O PLUS system. The
SimaPro datasets utilised to establish the module Improved quality water from public
fountains which models the burdens associated with the supplying of 1 litre of high quality
water, are also reported in the table.
Table 4.48: Major consumptions and processes associated with the delivering of improved quality water
through the H2O plus system from public fountains
l
kWh
Amount
Unit/litre
1.08
0.01
Polypropylene granules manufacturing
and respective extrusion in pre-filter
kg
1.5×10-5(2)
Activated carbon (GAC) manufacturing
Incineration of polypropylene pre-filter
kg
kg
4.17×10-5
1.5×10-5
Landfilling activated carbon filter
kg
4.17×10-5
l
0.08
Resources/Energy/Processes
Water
Electricity
Treatment of rejected water
Unit
SimaPro Module1
Tap water, at user, from surface origin
Electricity, medium voltage, at grid/IT
Polypropylene, granulate, at
plant/RER,
Extrusion plastic film/RER
Carbon coke
Disposal, inert waste, 5% water, to
inert material landfill/CH
Treatment, sewage, unpolluted, to
wastewater treatment, class 3/CH
(2) The value reported is the amount calculate. According to a conversion efficiency of 97.6%, the
burdens of the manufacturing and of the subsequent extrusion of 1.54×10-5 kg of virgin granules are
actually accounted for
278
Water transportation and preservation
As anticipated, the possibility of the utilisation of a private car for the roundtrip between
consumers houses and the public fountains is explored in this scenario. Being this a subjective
choice which relies upon many factors such as the distribution of fountains on the served
territory as well as the age and the habits of the consumers, the contribution of this life cycle
stage will be clearly indicated in the results.
The distance to be covered is defined, at a first instance, on the basis of the average distance
separating public fountains placed in the municipality of Florence from the respective city
centre which results to be of about 5.5 km. This value is therefore assumed to be the distance
to be covered by a citizen during the roundtrip from its own house to a public fountain. The
value seems to be quite realistic if considering that the service provided by public fountains is
mainly oriented at the citizens of the municipality in which they are established. Sensitivity
will be however performed on this parameter in order to evaluate the extent to which the
comparison of the performances of the present scenario with those of the other investigated
ones are affected (paragraph 5.3).
The dataset employed to models the burdens associated with the transportation is the one
previously employed in the case of one-way bottled water scenarios: Transport, passenger
car/RER. The trip is initially assumed to be made only for water transportation and therefore
its burdens, which are independent from the transported mass but depend only from the
travelled distance, are totally assigned to the overall volume of transported water. In order to
be coherent with one-way bottled water scenarios in which 9 litres of water are transported
during each trip, an amount of 9 bottles with a volume of 1 litre are assumed to be transported
also in this scenario and, therefore, 1/9 of the burdens associated with covering the distance of
5.5 km through a private car are assigned to 1 litre of water.
It must be noticed that the consumer trip could be carried out also for a further purpose such
as going to or coming back from the place of work and therefore only a part of the trip
burdens could be actually allocated to the volume of transported water. This aspect will be
taken into account during the sensitivity analysis (paragraph 5.3).
279
Life cycle of packaging
As specified above the typology of packaging assumed to be employed to conserve water are,
at a first instance, 1 litre glass bottles. They are assumed to have the same features of those
employed in the refilling scenario (475 g per bottle, paragraph 4.10.1) and characterized by a
very conservative lifespan of 1 year. Considering that 9 bottles are assumed to be employed
and that a volume of 152.1 litres is yearly consumed under each scenario, the mass of glass
bottles required to deliver 1 litre of water can be calculated as:
M glass 
475 g/bottle  9 bottles/year
 28.1 g/litre
152.1 litres/yea r
Bottles are assumed to be recycled at the end of their useful life and their life cycle is
modelled through the closed loop methodology and through the same processes utilised in the
refillable glass bottled water scenario (paragraphs 4.10.1 and 4.10.2) to which we refer for
further details. The module Glass bottles – life cycle is therefore established on the basis of
these considerations to model the whole life cycle of glass bottles.
It is also possible that plastic bottles, that are generally characterized by a lower life span, are
utilised for the same purpose, potentially assigning to the scenario different environmental
performances. This possibility will be therefore explored during the sensitivity analysis
(paragraph 5.3).
Washing of bottles by means of a residential dishwasher was instead not included because it
is considered to be an uncommon practice, while they are expected to be only rinsed after
every use. These consumptions are however not quantified.
The processes concerning improved quality water delivering, water transportation and bottles
life cycle are utilised to build up the module Public water, from surface origin, at consumer
house, which models the burdens associated with the delivering of 1 litre of improved quality
water from public fountains, and its transportation to consumers houses by means of 1 litre
glass bottles.
The whole scenario is finally implemented in the module Waste prevention scenario1b, (tap
water-surface source) which accounts for the fact that 152.1 litres of water have to be
delivered under each scenario, by recalling the previous module.
280
The most important processes described in the inventory of this scenario and the respective
magnitude are summarised in table D.5.
4.10 Waste prevention scenario 2A (Utilisation of refillable glass bottled
water)
As anticipated, besides the utilisation of public network water, also two preventive scenarios
which foresee the introduction of a refilling system are considered. The last Waste
Framework Directive 2008/98/EC (European Parliament and Council, 2008) indeed points out
that prevention can be achieved also through product re-use and life span extension, as in the
case of the introduction of a refilling system.
In this scenario it is assumed that all the volume of water delivered through one-way bottles in
previous baseline scenarios (1, 2 and 3), is now supplied by means of 1 litre refillable glass
bottles. This particular container size is chosen since it is assumed to be representative of the
domestic consumption of bottled (mineral) water, being the greater size available among glass
bottles. Smaller formats such as 0.5 or 0.75 litres ones, are instead assumed to be more widely
used by the Horeca (Hotels, restaurants and cafés) channel and hence not targeted by domestic
prevention.
From a life cycle perspective, a refilling system can be considered a case of closed loop
recycling which could be modelled as depicted in figure 4.15, where  and  represents
respectively the user losses and the rejection rate at the bottling plant.
281
Raw materials
and
bottles production
[+(1-)] X kg
Bottles washing
and filling
 (1-)X kg
Waste
management
X kg
(1-) X kg
Distribution and
use
X kg
Waste
management
Figure 4.15: Conceptual model of a refilling system as a case of closed loop recycling
Unfortunately, the mentioned values are unknown while an average number of 10 uses is
instead provided by the examined bottling company and by another producer of bottled water
(Cottarelli, 2010). As consequence the system is analysed by scaling down of this factor the
amount of material required for bottles production as well as of the respective generated
waste.
A number of 10 uses per bottle could seem to be quite low if considering that glass bottles
could be potentially re-used an infinite number of time, but since this value is provided by
primary sources we have decided to employ it in the base case of the inventory, while
sensitivity will be performed on this parameter also on the basis of the information provided
by other sources (paragraph 5.3).
The amount of municipal waste generated under this scenario can be calculated on the basis of
the masses of the primary packaging materials involved in the system and reported in the first
column of table 4.49. In particular, bottles mass is obtained by averaging the ones of the
bottles utilised by the main Italian mineral water brands, reported respectively in table A.3
and A.1 of appendix A. Aluminium caps and paper labels masses are instead provided by the
examined company.
Considering then that a volume of 152.1 litres/inhabitant/year has to be supplied through these
packaging materials and that bottles are used 10 times, it is possible to estimate the amount of
282
waste generated by each packaging item and which has to be managed within the system, that
corresponds to a total amount of 7.65 kg/inhabitant/year (table 4.49).
Table 4.49: Primary packaging materials masses and amount of waste generated by the utilisation of refillable
glass bottles
Unit mass Packaging waste
(g)
(kg/inhab/year)
Glass bottle
475
7.22
Aluminium screw cap
1.75
0.266
Paper label
1.06
0.161
Total
7.65
Packaging material
As can be seen, an higher amount of waste has now to be managed with respect to all oneway bottled water baseline scenarios (4.104 kg/inhabitant/year) because of the higher mass of
glass bottles with respect to those made of PET. In this case it is the number of items that
eventually become waste that is reduced, indeed only about 15 bottles are generated as waste,
against the about 115 generated in one-way bottled water scenarios. This seems however to be
still compatible with the definition of waste prevention given by the last Waste Framework
Directive (European Parliament and Council, 2008), which defines as preventive those
measures that reduce the amount of generated waste, without specifying if it deals with mass,
volume or number of items. Even if it can be presumed that the definition allude to the mass,
this is actually not explicitly mentioned.
Despite bottles become waste either at user or at the bottling facilities (the ones rejected), they
are assumed to be totally handled by the municipal waste management system. Moreover,
since it can be expected that the major part of bottles is discarded nearby the bottling plant
when they do not more meet minimal quality requirements, rather than being discarded by
users, they are assumed to be 100% recycled since they substantially represent an
uncontaminated material flow.
According to the approach proposed in Rigamonti and Grosso (2009), we have considered
that the recycling process consists in re-melting post consumer bottles in a percentage of
83.5% together with virgin raw materials for the remaining 16.5%. The burdens associated
with the selection stage are considered as well, even if no material losses are assumed to
occur. Moreover the recovery efficiency in the melting furnace is assumed to be 100% as
reported by the above mentioned authors. Energy consumptions of selection and recovery
283
stages considered in the analysis are those specified in table 4.50 so as reported in Rigamonti
and Grosso (2009)
Table 4.50: Energy consumptions of glass selection and recovery processes (Rigamonti and Grosso, 2009)
Stage
Selection
Melting furnace
Consumption
22 kWh/t selected cullet
(as electricity)
5,200 MJ/t produced glass
(from heavy fuel oil)
The burdens of the avoided production of a generic virgin glass container are finally credited
to the system in an amount corresponding to that of bottles sent to recycling.
On the basis of these considerations the module Glass recycling is created in the software to
model the burdens associated with the recycling of 1 kg of glass.
Caps are used only one time and are assumed to be 100% recycled and employed for the
production of secondary aluminium ingots avoiding the same production from primary raw
materials. As reported in Rigamonti and Grosso (2009) a substitution rate of 1:1 and a furnace
recovery efficiency equal to 83.5% are considered, while a pre-treatment efficiency of 100%
is assumed, even if the respective burdens are accounted for as well. Energy consumptions
considered for selection and melting stages are specified in table 4.51, so as reported by the
mentioned authors.
Table 4.51: Energy consumptions of steel selection and recovery processes (Rigamonti and Grosso, 2009)
Stage
Selection and pre-treatments
Melting furnace
Consumption
Electricity:
64 kWh/t selected scraps
Methane:
18 m3/t input scrap
Electricity:
10 kWh/t produced Al
Methane:
100 m3/t produced Al
The process Aluminium recycling is built up on the basis of these considerations to account
for the burdens associated with the recycling of 1 kg of aluminium.
Labels are separated from bottles during the washing process and are assumed to be
incinerated. The module Paper incineration, already described in paragraph 4.5.1, is
employed to model this process.
284
Since bottles and caps will be considered to be partly manufactured from recycled material
(paragraph 4.10.2) both the approaches utilised for the recycled PET bottled water scenario
(paragraph 4.6) to deal with the issue of how to account for the recycling process within the
system boundaries (closed-loop and hybrid approach) are, in first instance, separately
employed. The approach that will result to assign the greatest overall environmental impact to
the present scenario will be however utilised for the final comparison among all the
investigated scenarios (paragraph 5.3). More precisely, according to the terminology adopted
in the detailed guide for LCA prepared by the Joint Research Centre of the European
Commission (JRC, 2010) recycling of bottles and caps, could be considered as an “open loop
– same primary route” case of recycling because it is not known if these products are actually
recycled into new bottles and caps or into other different products. However the same
practical procedure employed for closed loop recycling can also be applied to this last case
because it is not strictly necessary that the secondary good is used to manufacture the same
product but rather that replace the production of primary raw materials traditionally employed
to manufacture that specific product (i.e. melted glass or aluminium ingots for bottles and
caps respectively).
Considering therefore that the Ecoinvent datasets that will be employed to model glass bottles
manufacturing (paragraph 4.10.2) already account for the burdens associated with sorting and
re-melting of post consumer glass cullet with virgin raw materials in an amount of 0.72 kgglass
cullet/kg bottles
13
and that a 100% sorting efficiency is considered in view of the uncontaminated
nature of wasted glass bottles, figure 4.16 shows the mass flows and the magnitude of the
processes that will have to be included in the system in the case of the utilisation of the closed
loop approach. They are defined in view of the fact that 7.22 kg (or 47.5 g/litre) of bottles
have to be manufactured.
13
An equal market share between green and white glass bottles will be indeed considered (paragraph 4.10.2), in
the manufacturing of which the Ecoinvent datasets account for the fact that 83.5% and 60.5% of glass cullet are
respectively utilised. This means that bottles have an overall contents of recycled material of:
0.835
kg green glass
kg white glass
kg cullet
kg cullet
kg
 0.5
 0.605
 0.5
 0.72 cullet .
kg green glass
kg bottles
kg white glass
kg bottles
kg bottles
285
Virgin raw materials
2.02 kg (13.3 g/litre)
Glass bottles manufacturing
(sorting and re-melting of cullet
with virgin raw materials)
(5.2+2.02)=7.22 kg
(47.5 g/litre)
Unsorted glass cullet
7.22×0.72=5.2 kg
(34.2 g/litre)
Utilisation and waste generation
7.22 kg (47.5 g/litre)
Unsorted glass cullet
7.22×(1-0.72)=2.02 kg/year (13.3 g/litre)
Glass bottles recycling in
other systems
(sorting and re-melting with
virgin raw materials)*
2.02/0.835=2.42 kg
Avoided virgin glass
container production
2.42 kg
(*) Glass cullet are assumed to be employed in the manufacturing of a generic green glass
container in a percentage of 83.5%, together with virgin raw material.
Figure 4.16: Modelling of glass bottles life cycle as a case of closed loop recycling
Applying the same approach to the recycling of aluminium caps and considering that the
Ecoinvent dataset that will be employed to model the average production mix of aluminium
ingots assumes that 10.4% of them are derived from re-melting of post consumer aluminium
scraps, that 1.03 kg of scraps are required to obtain 1 kg of ingots and that a 100% efficiency
of scraps pre-treatment is assumed in view of their uncontaminated nature, it is firstly possible
to calculate the amount of post consumer aluminium scraps required to obtain 1 kg of
aluminium ingots as:
R Al scraps  0.104
kg Al from old scraps
kg Al ingots
 1.03
kg Al scraps
kg Al from old scraps
 0.107
kg Al scraps
kg Al ingots
Employing this value and remembering that 0.266 kg (or 1.75 g/litre) of caps have to be
manufactured, it is then possible to define the magnitude of the processes associated whit the
life cycle of aluminium caps to be included in the system when the closed loop approach is
applied, as showed in figure 4.17.
286
Manufacturing of aluminium ingots
from post consumer scraps
(0.0285/1.03)=0.0277 kg (0.18g/litre)
post consumer scraps
0.266×0.107=0.0285 kg
(0.19 g/litre)
Manufacturing of aluminium ingots from
primary raw materials and industrial scraps
0.238 kg (1.57g/litre)
Caps manufacturing
0.266 kg
(1.75 g/litre)
Utilisation and waste generation
0.266 kg (1.75 g/litre)
post consumer scraps
0.266×(1-0.107)=0.237 kg/year (1.56 g/litre)
Aluminium recycling in other systems
(re-melting in new ingots)
0.237 kg (1.56 g/l)
Avoided production of aluminium
from virgin raw materials
0.237 kg (1.56 g/l)
Figure 4.17: Modelling of aluminium caps life cycle as a case of closed loop recycling
According to the outcomes of the previous mass balances, the processes that in last instance
have to be directly considered to occur in the waste management system and that have to be
modelled when the closed loop approach is applied are:

recycling of glass bottles: 2.02 kg,

recycling of aluminium caps: 0.237 kg,

incineration of paper labels: 0.161 kg.
Finally, if the hybrid approach is instead utilised, the processes that have to be considered
refer to the whole amount of waste generated by the same primary packaging materials, and in
particular:

recycling of glass bottles: 7.22 kg,

recycling of aluminium caps: 0.266 kg,

incineration of paper labels: 0.161 kg (as in the previous case).
4.10.2 Life cycle inventory of refillable glass bottled water
Since this scenario is characterized by the utilisation of refillable glass bottled water, the most
important upstream life cycle processes associated with the delivering of such a service have
287
to be included in the analysis because their magnitude changes among the various
investigated scenarios. A detailed inventory concerning these processes will be therefore
carried out in the rest of the paragraph.
System description
The system taken as reference to carry out the inventory of refilling scenarios is represented
by the same bottling plant considered for the case of one-way bottled water scenarios, but
focusing on the glass bottling line which will be now synthetically described in order to better
understand mass and energy flows within the system itself.
The process begins with de-palletization of crates containing returned empty bottles, by
means of a suitable machine which withdraws crates layer by layer and places them on a
motorized platform where they are separated and positioned on a conveyor belt which
transfers them to the next stage of de-capping. Here an apposite machine unscrews and
removes caps remained on the bottles, which afterwards are drawn from crates and addressed
towards the bottles washer machine. At the same time crates are sent to crates-washer where
they are firstly pre-rinsed with water at about 40°C, washed with water and alkaline
detergents at about 50°C and finally rinsed with fresh water.
The functioning of the bottles washer machine is quite complex and foresees the following
stages, to which bottles undergo after being placed in apposite racks. Bottles are firstly turned
upside down and pre-rinsed with a water solution at the temperature of about 40-45°C,
coming from the rinsing stages which take place at the end of the washing process. Bottles are
then immersed in a first caustic bath containing about 18,000 litres of a water solution of
caustic soda (NaOH), defoaming and descaling additives at the temperature of 60°C, where
the process of labels removing begins. At the exit bottles are sprayed inside with a solution
drawn from a second caustic bath in which bottles are then immersed also to complete labels
removing. This bath has the same characteristics of the first one except for a lower
concentration of soda and a solution temperature of 70°C. At the exit, bottles are again
sprayed inside with a solution of soda and descaling agent at the temperature of 60°C drawn
from a separate basin of about 5,000 litres. Afterwards bottles are immersed in a rinsing bath
containing about 13,000 litres of a solution of water and a descaling additive at the
temperature of 50°C. At the end of this stage the rinsing procedure begins: bottles are sprayed
inside and outside during four consecutive stages with solutions drawn from four different
basins at the pressure of about 1.8 bar. Each basin is fed by pouring from the successive one
288
and the first two basins contain a solution of water with a sequestering agent and a peracetic
acid based disinfectant at the temperature of about 45 and 40 °C respectively. The last two
basins contain a not heated solution of water with the only disinfectant agent at the
temperature of about 30 and 20 °C respectively. The sequestering agent is fed in the second
basin, while the disinfectant is fed in the fourth one. A last internal rinsing is finally
performed with fresh mineral water at about 12°C and 2.2 bar at a constant flow rate of
15,000 l/h which feeds all the previous basins by pouring.
Baths and basins water is warmed up by heaters in which steam produced by an heavy fuel oil
boiler circulates. After the initial charge, water, soda and additives are periodically added to
restore the initial concentration which tends to modify because of losses.
After washing, empty bottles are checked by an electronic inspector which verifies the
absence of damages to the surface, the bottom and the thread and the absence of liquid within
the bottle. In contrary case they are discarded or sent again at the bottles washer intake.
Bottles are then filled at the right level with water coming from the three water storages, in
case saturated with carbon dioxide at the pressure of 1 bar.
Afterwards bottles are capped with crown or screw caps which, after being positioned are
shaped on the neck the first and on the thread the second. Labels are then applied by gluing
the full surface with cold glue.
At the end of these stages an electronic inspector verifies the presence of the cap of the label
and the right filling level. In negative case bottles are deviated from the main flow and sent
again at the beginning of the process.
Bottles are then drawn and placed in plastic (HDPE) crates. In particular 1 and 0.75 litres
bottles are placed in 12 pieces crates while 0.5 litres bottles within crates by 20 pieces.
Crates are in turn palletized in a precise number of layers composed by a precise number of
crates. In particular 1 and 0.75 litres bottles are charged upon 95×120 cm pallets in 5 layers
by 9 crates, for a total of 540 bottles, while 0.5 litres bottles are charged upon a pallet of the
same dimensions but with 6 layers, for a total of 1,080 bottles.
The delivering of transport units to local distributors follows the same procedures of one-way
bottled water with the exception that the return trip is done by charging the same transport
units with empty bottles. Transportations from local distributors to consumers houses and vice
versa are generally done with small trucks with a full-load mass which does not outweigh 7
tonnes.
289
System boundaries
Similarly to the case of one-way bottled water, the following processes are included in the
inventory, on the basis of the data and the information that have been possible to collect from
the examined bottling plant:

manufacturing of primary packaging materials: bottles, caps and labels,

manufacturing of crates employed as secondary packaging material,

manufacturing of pallets materials and of the plastic ligature for employed for water
transportation,

bottling plant operations including bottles washing, filling, capping, labelling, packing in
crates and palletization. Filler machine washing is included as well,

end of life treatments of the materials which were not considered to be handled by the
municipal waste management system: recycling of plastic crates and of transport
packaging materials,

roundtrip transportation from the bottling plant to local distributors and from these lasts to
consumers houses are finally considered.
As done for the previous one-way bottled water scenarios, the burdens associated with
production and disposal of capital goods such as infrastructures and machineries are not
included in the analysis according to the same reasons.
Figure D.6 provides a graphical representation of the major processes that are included in this
scenario when modelled through the closed loop approach and that will be described during
the following detailed inventory.
Reference flow
Coherently with the previous investigated one-way systems, the inventory is carried out by
considering as reference flow “1 litre of mineral water, bottled and delivered to the consumers
by means of 1 litre refillable glass bottles”. All inputs and outputs have been therefore related
to this flow.
Data sources
Packaging material masses are provided by the examined bottling company except for bottles,
for which an average value is defined, how will be better explained forth. Data concerning
290
energy and raw materials consumptions for bottling plant operations are always provided by
the same reality. Also in this case inventory data employed to model materials manufacturing
and energy generation are taken, as much as possible from the well established Ecoinvent
database implemented in the software SimaPro.
Detailed inventory
Primary packaging materials are represented by glass bottles, aluminium screw caps and
paper labels.
The unit masses considered for these materials are the same employed for the definition of
waste generation and are reported again in the first column of table 4.52.
Since the container capacity is of 1 litre, these unit masses are already expressed with respect
to the reference flow except for bottles one, whose mass must be scaled down by 1/10, to
account for the average number of uses they are subject to, resulting therefore equal to:
M glass 
475 g/bottle
 47.5 g/litre
1 l/bottle/use  10 uses
Table 4.52: Amount of primary packaging materials involved in the delivering of refillable glass bottled water
Unit mass Mass related to the reference flow
(g)
(g/litre)
Glass bottle
475
47.5
Aluminium screw cap
1.75
1.75
Paper label
1.06
1.06
Packaging material
Since the actual market share between green and white glass bottles is unknown, we have
chosen to consider an equal distribution between the two typologies of material, which mainly
differ for the amount of glass cullet employed in their manufacturing. According to Hischier
(2007c), this amount is indeed equal to 60.5% for white glass and 83.5% for green glass.
Lower environmental burdens are therefore expected to be associated with the utilisation of
this last.
To model glass bottles manufacturing the two datasets Packaging glass, green, at plant/RER
and Packaging glass, white, at plant/RER are employed. They just account for the burdens
291
associated with the production of a generic glass container from melting of glass cullet in the
above specified percentages, together with virgin raw materials for the remaining part.
Aluminium caps are manufactured through a mechanical press which forces aluminium sheets
within moulds that are the reverse shape of the caps. To obtain sheets, aluminium ingots are
firstly hot-rolled at about 500°C into sheets of 2-8 mm of thickness which are then cold rolled
to the final thickness of 0.2-6 mm (Classen et al., 2009). Aluminium ingots can be produced
out of virgin raw materials, or by re-melting manufacturing scraps or post-consumer scraps.
Each one of these processes are inventoried in Ecoinvent and also an European production
mix for an unspecific aluminium is provided (Aluminium, production mix, at plant/RER). It
considers a share among the three aluminium typologies of 68%, 21.6% and 10.4%
respectively and is employed to model aluminium ingots manufacturing. Aluminium rolling is
modelled with the dataset Sheet rolling, aluminium/RER while the process of caps moulding
is assumed to be approximated by the module Cold impact extrusion, aluminium, 1
stroke/RER. All these processes are introduced in the new module Aluminium caps created on
purpose, to model the production of 1.75 g of aluminium caps.
Paper label production is instead modelled with the same dataset employed for one-way
bottles labels (Paper, wood-containing, supercalendered (SC), at regional storage/RER),
according to the same reasons.
The new module Primary packaging materials-glass is created to account for production
burdens of the actual amount of primary packaging materials involved in the system, by
recalling the processes above described.
Secondary packaging materials life cycle
As early specified during the system description, 1 litre glass bottles are packed within 12
pieces crates made of high density polyethylene (HDPE) with a mass of about 2 kg and which
are estimated by the company to be employed for 100 transportation cycles before damaging.
The mass of HDPE expressed with respect to the reference flow is then equal to:
M HDPE 
2,000 g/crate
 1.67 g/litre
12 l/crate/trip  100 trips
292
Crates are assumed to be manufactured through injection moulding of virgin HDPE granules
and to be recycled at the end of their useful life, even if not handled by the municipal waste
management system.
The Ecoinvent datasets and the assumptions considered to model the processes of HDPE
manufacturing and of injection moulding are those already described in paragraph 4.5.2.
HDPE recycling was instead discussed in paragraph 3.3.2. These modules are therefore
employed to create the new module HDPE crates-glass which models the production of 1.67
g of HDPE crates through the injection moulding of 1.68 g of virgin HDPE granules
(conversion efficiency 99.4%), and their recycling.
The transport unit of 1 litre glass bottles is constituted by a wooden pallet with dimensions
95×120 cm (greater than the one employed for one-way PET bottles) loaded with 45 crates
disposed in 5 layers by 9 crates each one, for a total amount of 540 transported litres, kept
stable by a heat welded plastic ligature.
Masses of pallet components are not known in this case and are therefore defined by
assuming them as proportional to the load surface. Considering that a standard 80×120 cm
EUR-EPAL pallet has a surface of 0.96 m2 while a 90×120 cm pallet has a surface of 1.14 m2,
the masses of standard EUR-EPAL pallet components (first column of table 4.53) have to be
scaled up by a factor of 1.14/0.96=1.19. The values resulting from this operation are shown in
the second column of table 4.53 and are employed to modify the values reported in the
module EUR-flat pallet/RER previously employed for the modelling of pallet materials
manufacturing in one-way bottled water scenarios. So modified module is named as Pallet
95×120 cm and accounts for the burdens associated with the manufacturing of the amount of
raw materials required to constitute one pallet unit.
Also in this case a number of 20 transportation cycles per pallet are considered and therefore
the amount of pallet units required by the system under investigation and expressed with
respect to the reference flow is equal to:
No.pallet 
1 pallet unit
 9.26  10 5 pallet units/litr e
540 l/pallet/t rip  20 trips
293
The manufacturing of such an amount of pallet units is therefore modelled through the above
described module (Pallet 95×120 cm).
Finally, by multiplying this last obtained value by the masses of each pallet components
before calculated (second column of table 4.53), it is possible to express them with respect to
the reference flow, as reported in the third column of table 4.53.
Table 4.53: Amount of pallet materials involved in the delivering of refillable glass bottled water
Total mass 80×120 Total mass 95×120 Total mass 95×120
(kg)
(kg)
(kg/l)
Wooden boards
16.6
19.7
1.83×10-3
8
9.5
8.8×10-4
Total wood
24.6
29.2
2.7×10-3
Steel nails
0.195
0.232
2.14×10-5
Total mass
24.8
29.4
2.73×10-3
Input materials
As mentioned above, pallet load is kept stable by an heat-welded low density polyethylene
ligature whit a unit mass of 21 grams, which in relation to the reference flow is equal to:
M LDPE ligature 
21 g/pallet
 0.039 g/litre
540 l/pallet
Polyethylene ligature is assumed to be produced through extrusion of virgin LDPE granules
and the module Polyethylene ligature is created to account for the burdens associated with the
production of 0.039 g of ligature starting from 0.04 g of virgin LDPE granules with the same
approach already employed, for instance, for heat shrink films (paragraph 4.5.2).
Finally, pallet materials are assumed to be recycled at the end of their useful life and therefore
the burdens associated with the recycling of 2.73×10-3 kg of wood (Wood recycling) and
2.14×10-5 kg of steel (Steel recycling) are accounted for (table 4.53).
Plastic ligature is assumed to be incinerated and the module Plastic incineration already
described models this process.
The module Transport packaging materials-glass is created to account for burdens associated
with the whole life cycle of transport packaging materials by recalling the above mentioned
modules.
294
Glass-line bottling plant operations differs from those of PET line mainly for the absence of
the blow moulder, of the heat-shrink oven and for the presence of the bottles washer.

Energy consumptions
The amount of electricity required for all glass line operations can be calculated by
remembering that the examined company estimates that of the whole annual consumption of
electricity (1,423,626 kWh during 2009), 2% is associated with services while of the
remaining part only 30% is ascribable to the glass line. Therefore, in view of a total volume of
32,000,000 litres packaged in glass bottles during the same year, the specific consumption of
electricity can be calculated as:
Ee GLASS line 
1,423,626 kWh/y  0.98  0.3
32,000,000 litres/y
To this value also services consumptions (3.56×10-4 kWh/l) must be added to obtain the
actual value to consider in the analysis:
Ee LCA_GLASS  0.0131  3.56  10 4  0.0134 kWh/l
Electricity generation is modelled through the Ecoinvent dataset Electricity, medium voltage,
at grid/IT.
Besides electricity, also the amount of thermal energy employed for the generation of the
steam utilised to heat water inside the baths of the bottles washer, has to be taken into
account. Its quantification will be made separately in this paragraph.

Raw materials consumptions
Specific consumptions of lubricating oil for maintenance as well as of detergents and waters
for filler machine washings are the same of those calculated for PET line operations since
they were defined by considering the total volume of water produced by the company
(paragraph 4.5.2).
295
Besides them, also consumptions of caustic soda, detergents and water employed in the
bottles washer must be considered, as will be made later in this paragraph.

Since detergents consumption for filler machine washings is the same of the PET line, also
waterborne emissions associated with wastewaters originating from this operation are of
consequence of the same magnitude and are modelled with the same assumptions made in
paragraph 4.5.2.

Waste flow
Only the disposal through incineration with energy recovery of an amount of mineral oil
analogous to that calculated for baseline scenario 1 (paragraph 4.5.2) has to be considered as
end of life process.

Bottles washing
Since a specific module (Bottles washing) is created in the software to account for the burdens
associated with this operation, we have chosen to maintain separate their discussion.
As already described, an heavy fuel oil boiler provides steam for caustic baths heating. Since
this typology of fuel is employed for reason of unavailability of the methane supplying
network, we have chosen to consider the same amount of heat as produced from methane
instead of heavy fuel oil. This in order not to associate potentially high environmental burdens
to the refilling system in view of a choice made only on the basis of local conditions, as well
as to allow a fair comparison among the investigated scenarios.
An amount of 255,000 kg of heavy fuel oil was consumed during 2009 by the examined
company, which estimates that only 70% is associated with the washing process, being the
remaining associated with services. Considering therefore an oil lower heating value of 40
MJ/kgoil (Dones et al., 2007), the specific consumption of thermal energy can be calculated as:
Et washing 
255,000 kg/y  0.7  40 MJ/kg
 0.223 MJ/litre
32,000,000 litres/y
This amount of energy is therefore assumed to be provided by a methane boiler, modelled
with the Ecoinvent dataset Natural gas, burned in industrial furnace >100kW/RER.
296
Annual consumptions of caustic soda and detergents registered by the company during the
year 2009 are reported in table 4.54 both in absolute and in specific terms, which are
calculated by dividing the former by the total volume of water packaged in glass bottles
during the same year (32,000,000 litres).
Manufacturing of soda is modelled with the Ecoinvent dataset Sodium hydroxide, 50% in
H2O, production mix, at plant/RER, while modelling of detergents components
manufacturing is carried out with the same approach applied for detergents utilised in filler
machine washing (paragraph 4.5.2). Their composition and the respective Ecoinvent datasets
used for modelling are reported in tables from C.5 to C.8 of appendix C.
Table 4.54: Consumptions of caustic soda and detergents employed for bottles washing
Materials
Amount (kg) – year 2009 Specific amount (kg/litre)
Caustic soda (NaOH) - 30% solution (m/m)
85,000
2.66×10-3
Descaling agent (Divo MR)
8,000
2.5×10-4
1
Defoaming agent (Integra HD)
7,000
2.19×10-4
Sequestering agent (Divo RL)
3,000
9.38×10-5
Disinfectant (Divosan forte)2
1,700
5.31×10-5
(1) Inventoried only in terms of demineralised water because of data lacking
(2) Part of this amount is actually also utilised for weekly filler machines washings but it was totally
attributed to bottles washing according to a conservative approach
Water consumptions associated with bottles washing are not monitored by the company and,
therefore, they are estimated by considering the features and the functioning of the bottles
washer.
In particular, the process foresees that:

the first two caustic baths are charged with a volume of about 18,000 litres and every
20 working day, the solution from the second bath is transferred to the first bath,
which is discharged, while the second is renewed,

the third caustic basin and the fourth rinsing bath are charged with a volume of 5,134
litres and 13,460 litres respectively and are renewed every 10 working days,

the four final rinsing basins are charged with a volume of 1,310, 785, 815, 1,520 litres
respectively and are renewed every day,

a constant flow rate of 15,000 l/h is sprayed from jets bars for final rinsing and is fed
to the previous rinsing basins to allow their pouring.
Assuming therefore an amount of 250 working days per year and of 8 hours per day, the
specific consumption of water can be estimated as follow:
Vwater 
297
18,000  18,000  250/20  (5,134  13,460)  250/10  (1,310  785  815  1,520)  250  15,000  8  250
 1 litre/litre
32,000,000
It must be noticed that this value is probably underestimated because of the periodical reintegrations which are required as consequence of process losses. This consumption of water
is however assigned to the process in form of natural resource (Water, well, in ground).
Waterborne emissions of COD, nitrogen (N) and phosphorus (P) are finally defined by
considering their concentration in the utilised detergents and the average removal efficiencies
achievable in a wastewater treatment plant, according to the approach already employed to
define the emissions associated with filler machine washings (paragraph 4.5.2). Table 4.55
shows the amounts of these emissions both at the gate of the bottling plant and after
purification in wastewaters treatment plant. These lasts are the value to be considered in the
analysis.
Table 4.55: Waterborne emissions from the bottling plant and to the environment associated with bottles
washing
Input to the WWTP  removing Output from WWTP
(g/lbottled water)
(g/lbottled water)
(%)
-1
COD
2.83×10
42.5
1.63×10-1
N
8.01×10-3
25
6.01×10-3
-3
P
1.71×10
20
1.37×10-3
(*) Calculated considering a 85% removal efficiency for BOD and an
average rate COD/BOD=2 into urban sewage (Bonomo, 2008)
Pollutant
The treatment process of an unpolluted sewage is again considered to model the burdens
associated with the depuration of wastewaters originating in this stage (Treatment, sewage,
unpolluted, to wastewater treatment, class 3/CH).
Finally, since it was not possible to quantify consumptions of cryogenic CO2 employed at the
plant to neutralize the alkalinity of the sewage, they are neglected in the present study.
Transportations
With regard to the transportation from the bottling plant to the local distributor, the mass of
the complete transport unit has to be considered. It is composed by the pallet (29.4 kg), the 45
crates (45×2 kg), the 540 bottles (540×0.475 kg) with caps (540×0.00175 kg), labels
(540×0.00106 kg) and the contained water (540×1 kg) which correspond to a total mass of
917.4 kg that in specific terms can be calculated as:
298
M transport_ full 
917.4 kg/pallet
 1.7 kg/litre
540 litres/pallet
Also the return trip of empty bottles have to be considered. The mass to be transported in this
case can be calculated from the previous value by subtracting the mass of water (540 kg),
obtaining hence:
M transport_ empty 
(917.4  540) kg/pallet
 0.7 kg/litre
540 litres/pallet
The value to be used in the software can be now obtained by multiplying the transport mass
(1.7+0.7=2.4 kg/litre) by the covered distance (300 km, paragraph 4.5.2) which results equal
to 720 kg×km/litre. The module employed to model transportation burdens is the same of the
one utilised in one-way scenarios: Transport, lorry >16t, fleet average/RER, available in
Ecoinvent.
The delivering transportation from the local distributor to consumers houses, which generally
occurs with small lorries, has finally to be considered. The transport unit in this case is the
single crate of 12 bottles complete of caps, labels and contained water, for a total mass of 19.7
kg and a specific mass of 1.64 kg/litre. During the return trip an empty mass of 7.7 kg is
instead transported which corresponds to a specific one of about 0.64 kg/litre. An overall
distance of 20 km is arbitrarily assumed to be representative of an average delivering trip
(roundtrip 40 km). The value to be considered is therefore equal to (1.64+0.64)kg/l×20
km=45.6 kg×km/litre and the transport stage is modelled with the dataset Transport, lorry
3.5-16t, fleet average/RER.
The whole inventory is implemented in a new module, Bottled water, glass refillable, 1 litre,
at consumer, which by recalling all the modules described up to now models the all the
upstream burdens associated with the delivering of 1 litre of water to the consumers by means
of 1 litre refillable glass bottles. The whole scenario in instead implemented in the module
Waste prevention scenario 2A (refillable glass bottled water) which accounts for the burdens
associated with the treatments of municipal wastes generated in this scenario as well as with
the delivering of 152.1 litres of water by means of 1 litre refillable glass bottles.
299
The major upstream life cycle processes which characterize this scenario and the respective
magnitude are summarized in table D.6.
4.11 Waste prevention scenario 2B (Utilisation of refillable PET bottled
water)
A refilling system which employs 1 litre virgin PET bottles instead of glass ones is finally
considered in order to evaluate the influence of bottles material on the environmental
performances of a refilling system. The utilisation of this typology of containers, not only for
water but also for soft drinks packaging, represents indeed a commonly utilised option, for
instance, among northern European countries such as Germany and Denmark (Danish EPA,
1998; UBA, 2000a; GDB, 2010).
4.11.1 Description of the packaging system
Since in Italy such a delivering option still lacks, the specifications of the packaging system to
be studied are derived from the literature and in particular from LCA studies dealing with the
German context, country in which such a system is well established. They are specified in the
following list.

The first important but quite dated source is the comprehensive LCA study published by
the German Federal Environmental Agency (UBA – Umweltbundesamt) which compares
27 packaging systems for the delivering of mineral water, carbonated soft drinks, juices
and wines (UBA, 2000a; 2000b), including also 1 litre and 1.5 litres refillable PET bottles
for lemonade as well as 1.5 litres bottles for water.

One more recent LCA study conducted by the Institute for Energy and Environmental
Research (IFEU-Institut für Energie und Umweltforschung), which compares the use of
1.5 litres one-way PET bottles with that of 0.7 litres glass and 1 litre refillable PET bottles
belonging to the pool of the Cooperative of German Mineral Wells (GDB: Genossenschaft
Deutscher Brunnen) for mineral water delivering, also provides more updated information
(IFEU, 2008).
300

A last LCA study always performed by IFEU on behalf of the German Industrial
Association of Plastic Packaging (Industrievereinigung Kunststoffverpackungen) which
compares several packaging systems for mineral water and carbonated soft drinks
delivering, used for both at home or immediate consumption, also including 0.5, 0.75, 1
and 1.5 litres refillable PET bottles belonging to the GDB pool is finally considered as
source of data (IFEU, 2010).
For the present scenario 1 litre refillable PET bottles are in particular considered among the
various available delivering options in order to allow a fair comparison with the glass
refillable scenario. The utilisation of a greater size, i.e. 1.5 litres, would indeed reduce the
material intensity of the system thus involving greater potential benefits in its possible
implementation. The opposite situation would occur if a smaller size was considered.
The specifications of the packaging system for 1 litre bottles considered by the above
mentioned studies as well as the values assumed for the present one, in the choice of which,
data from more recent sources are preferred, are reported in table 4.56.
301
Table 4.56: Specifications of the packaging system for 1 litre refillable PET bottled water
Content
UBA (2000a)
IFEU (2008)
Lemonade
Water
Pool
Source
IFEU (2010)
Water and carbonated
soft drinks
GDB
This study
Water
GDB
GDB
Primary packaging
PET bottle mass [g]
70.8
62
62
62
Closure mass (HDPE) [g]
3.2 (PP)
3.2
3.2
3.2
Label mass (PP) [g]
1.2
0.6
0.6
0.6
Secondary packaging
Crate mass (HDPE) [g]
1,550
1,550
1,850
1,8501
Bottles per crate
12
12
12
12
Transport packaging
Pallet typology
EUR
EUR
EUR
EUR
Pallet mass [kg]
22
24
24
24.82
Ligature mass (PE) [g]
18
18
18
18
Pallet composition
Crates per layer
8
8
8
8
Layer per pallet
5
5
5
5
Crates per pallet
40
40
40
40
Bottles per pallet
480
480
480
480
Water volume per pallet (litres)
480
480
480
480
Number of uses
Bottles
14
15
15
15
Crates
27
100
120
1003
Pallets
25
25
204
(1) Higher value between the two more recent sources
(2) The mass of 24.8 kg is the value actually calculated on the basis of the Ecoinvent module employed
to model pallet materials manufacturing (paragraph 4.5.2)
(3) Lower value between the two more recent sources
(4) A number of 20 uses is considered for reason of coherence with previous one-way and refillable
glass bottled water scenarios
On the basis of the values reported in table 4.56 it is therefore possible to estimate the amount
of waste generated by the consumption of the 152.1 litres of water that in this scenario are
delivered through 1 litre refillable PET bottles, by considering that these lasts are assumed to
be used for 15 times (table 4.57).
Table 4.57: Amount of waste generated by the consumption of refillable PET bottled water
Packaging material
PET bottles
HDPE caps
PP labels
Unit mass Packaging waste
(g)
(kg/inhab/year)
62
0.629
3.2
0.487
0.6
0.091
Total
1.21
302
As can be observed, besides the reuse of a good, the utilisation of such a system involves an
actual prevention in term of mass, since only 1.21 kg/inhabitant/year of waste are generated,
against the about 4.1 kg/inhabitant/year which characterizes one-way bottled water baseline
scenarios and the 7.65 kg of refillable glass bottled water one.
At the end of their utilisation cycles, bottles are assumed to be 100% recycled, as well as glass
ones, since the major part of them can be considered to become waste nearby bottling
facilities when they are rejected because they do not more satisfy minimal quality
requirements. This uncontaminated flow is therefore expected to be directly sent to recycling
as well as glass bottles. Caps are used only one time and are assumed to be recycled as well,
while paper labels separated from bottles during the washing process are assumed to be
incinerated. Therefore, the processes which occur into the waste management system and that
have to be modelled are:

recycling of bottles: 0.629 kg,

recycling of caps: 0.487 kg,

incineration of labels: 0.091 kg.
The process of plastic selection is not considered in view of the uncontaminated nature of the
bottles waste flow.
The already described modules PET granules from PET bottles/containers recovery, HDPE
granules from containers recovery and plastic incineration are respectively employed to
model the above mentioned processes.
4.11.3 Life cycle inventory of refillable PET bottled water
The most important differences with respect to the inventory of refillable glass bottled water,
to which we refer for all the aspects not better detailed in the rest of the present one, are
reported in this paragraph.
Coherently with the inventory of all the scenarios considered up to now, the adopted reference
flow is “1 litre of water, bottled and delivered to the consumers by means of 1 litre refillable
PET bottles”.
Figure D.7 provides a representation of the upstream life cycle processes included in the
present scenario and in particular highlights those which differ from the previous refillable
glass bottled water scenario.
303
The masses of primary packaging materials reported in table 4.56 already represent the actual
amounts required to deliver 1 litre of water except for bottles, which amount must be scaled
down by 1/15 in order to account for the number of times they are actually used. On the basis
of these considerations table 4.58 reports the values calculated with respect to the reference
flow which have to be employed in the analysis.
Table 4.58: Amount of primary packaging materials involved in the delivering of refillable PET bottled water
Packaging material
PET bottles
HDPE caps
PP labels
Unit mass Mass with respect to the reference flow
(g)
(g/litre)
62
4.13
3.2
3.2
0.6
0.6
Total
7.93
Since the consumption of electricity calculated for glass line operations in paragraph 4.10.2
does not include the amount associated with preforms stretch blow moulding, the burdens
associated with this process have to be modelled separately. In particular the burdens
associated with the manufacturing of 4.13 g of finished bottles have to be considered
according to table 4.58. For this purpose the Ecoinvent dataset Stretch blow moulding/RER,
which models the entire continuous process of preforms injection and direct stretch blowing
in bottles, is employed, but updating it with the data provided by the eco profiles developed
by TNO on behalf of PlasticsEurope just concerning this typology of process (TNO, 2010).
Table 4.59 shows the way in which data from the two sources are combined to create the
updated module which is named Injection stretch blow moulding. This last is therefore
employed to model the manufacturing of 4.13 g of PET bottles starting from the same amount
of virgin PET granules (Polyethylene terephtalate, granulate, bottle grade, at plant/RER). All
these choices are justified considering that also in the above mentioned studies (IFEU, 2008;
2010) refillable PET bottles are considered to be manufactured from only virgin raw materials
and outside the bottling plant within independent facilities.
304
Table 4.59: Values employed for the inventory of the injection stretch-blow moulding process
Inputs
Unit Ecoinvent dataset PlasticsEurope eco-profile This study
(resources/materials/energy)
Water
kg
110
0.0618
0.0618
Plastic (PET granules)
kg
1.0215*
1
1
Electricity
kWh
2.55
1.497 (5.39 MJ)
1.497
Lubricating oil
kg
0.00196
0.00196
Cardboard (as packaging material)
kg
0.0323
0.1037
0.1037
Pallets (wood)
kg
0.0989
0.0989
Output (emissions/waste)
Heat, waste
MJ
9.17
9.17
Plastic scraps
kg
0.0215
Unspecified waste
kg
0.01
(*) This value implicitly means that a 97.9 conversion efficiency of granules in bottles has to be considered
according to the Ecoinvent dataset, while in the PlasticsEurope eco-profile a 100% conversion efficiency
seems to emerge. Due to the more recent nature of this last source a 100% efficiency is also considered in the
present study
Manufacturing of HDPE caps is assumed to be made through injection moulding of virgin
HDPE granules and is modelled with the same approach utilised for one-way bottled water
caps (paragraph 4.5.2). In particular the Ecoinvent dataset Injection moulding/RER is utilised
to model the production of 3.2 g of HDPE caps starting from 3.22 g of virgin HDPE granules
(Polyethylene, HDPE, granulate, at plant, RER) in view of a 99.4% conversion efficiency.
Polypropylene (PP) labels are finally assumed to be manufactured through extrusion of virgin
PP granules and in particular the module Extrusion, plastic film/RER is employed to model
the production of 0.6 g of label starting from 0.615 g of virgin PP granules (Polypropylene,
granulate, at plant/RER) according to a 97.6% conversion efficiency. Printing of labels is not
considered because of data lacking.
Secondary packaging materials manufacturing
The amount of HDPE crates required to deliver 1 litre of bottled water can be defined by
considering that they contain 12 bottles and are assumed to be used 100 times (table 4.56).
M HDPE 
1,850 g/crate
 1.54 g/litre
12 l/crate/trip  100 trips
Manufacturing of crates is assumed to be made through injection moulding of virgin HDPE
granules and is modelled with the same datasets employed for HDPE caps.
305
Recycling is also considered as end of life option for crates and is modelled with the already
described module HDPE granules from containers recovery (paragraph 3.3.2).
The amount of standard EUR-EPAL pallet units required to deliver 1 litre of water can be
calculated by considering that, according to table 4.56, they are charged with 5 layers of 8
crates containing 12 bottles each one, for a total volume of 480 litres to be transported, and
that they are assumed to be used for 20 times:
No.pallet 
1 pallet unit
 1.04 10 4 pallet units/litr e
480 l/pallet/t rip  20 trips
Pallets material manufacturing for an amount of pallets units pair to the value just calculated
is modelled through the Ecoinvent dataset EUR-flat pallet/RER, already employed for oneway bottles systems. Moreover, by multiplying the same value by the mass of each pallet
component, it is possible to calculate the amount of materials involved in the delivering of 1
litre of water and that have to be managed at the end of pallet life cycle (table 4.60).
In particular, as done for all the others bottled water scenarios, pallet materials are assumed to
be recycled and therefore the burdens associated with the recycling of 2.56×10-3 kg of wood
(Wood recycling) and 2.03×10-5 kg of steel nails (Steel recycling) are accounted for.
Table 4.60: Amount of pallet materials involved in the delivering of refillable PET bottled water
Total mass Total mass
(kg/unit)
(kg/litre)
Wooden boards
16.6
1.73×10-3
8
8.33×10-4
Total wood
24.6 2.56×10-3
Steel nails
0.195
2.03×10-5
Total
24.8 2.58×10-3
Input materials
The amount of low density polyethylene ligature (employed to assure stability to the pallet
load) required to deliver 1 litre of water can be calculated by remembering that it has a unit
mass of 18 g (table 4.56) and that the volume of water transported by one pallet is of 480
litres:
306
M LDPE ligature 
18 g/pallet
 0.0375 g/litre
480 l/pallet
Manufacturing of ligature is considered to be made through extrusion of virgin LDPE
granules as in the previous glass bottled water scenario and the employed datasets are the
same. Analogously it is assumed to be employed only one time and then incinerated (Plastic
incineration).
With regard to bottling plant operations, the only difference between the present system and
the glass refillable one concerns bottles washing. On the basis of the indications provided by
one producer of bottles washers (Spotti, 2010), we have indeed recognized that same
adjustments have to be made when dealing with washing of PET bottles. In particular, while
the maximum temperature of the various caustic solutions in which bottles are immersed
varies between 60 °C and 80°C for glass ones, it must instead not exceed 60 °C for PET
bottles, in order to avoid higher deformations and matting. More in depth, according to the
same source, this leads to a reduction of thermal energy consumptions to at most the half of
those involved in glass washing. For the same reasons the permanence time within the
solution must be reduced of about 25% (from 5 minutes to at most 3.5-4 minutes), involving
an equivalent increase of the productivity of the bottles washer (expressed as bottles per
hour).
On the basis of this consideration we have decided to make a rough estimate of these potential
savings by assuming that with half of the actual amount of thermal energy consumed by the
examined bottling plant for washing glass bottles during 2009 it would have been possible to
produce a 25% higher volume of bottled water. In particular, remembering that of the 255,000
kg of heavy fuel oil (LHV=40 MJ/kg) consumed during 2009, only 70% are actually
ascribable to the washing process, and that 32 millions litres of water were bottled during the
same year, it is possible to estimate the specific consumption of thermal energy as follow:
Et washing 
(255,000 kg/y  0.7  40 MJ/kg)  0.5
 0.089 MJ/litre
(32,000,000 litres/y) 1.25
307
A last consideration must be done with regard to caustic soda consumption. Indeed, always
according to Spotti (2010), its concentration within the caustic baths has to be maintained at a
level of about 0.4%-0.5% when PET bottles have to be washed, against the 1.5-2% utilised
for glass bottles, in view of the above mentioned considerations concerning PET degradation.
This would lead therefore to lower consumptions of caustic soda either during the initial
charge of the baths as well as during its periodical restoring. It was however not possible to
quantify these potential savings which are also function of the level of dirtiness of the bottles
to be washed.
With regard to the other burdens associated with bottling plant operations, they are assumed
to be identical to those of the refillable glass bottled water system since bottles are expected to
undergo to similar process stages.
Transportations
The mass of the whole transport unit utilised for the trip from the bottling plant to the local
distributor can be calculated considering that it is composed by the pallet (24.8 kg), the 40
crates (40×1.85 kg), the 480 bottles (480×0.062 kg), with caps (480×0.0032 kg), labels
(480×0.0006 kg) and the contained water (480×1 kg), which correspond to a total mass of
610.4 kg that in specific terms can be calculated as:
M transport_ full 
610.4 kg/pallet
 1.27 kg/litre
480 l/pallet
The mass to be transported during the return trip of empty bottles can be instead calculated
from the previous value by subtracting the mass of water (480 kg), obtaining hence:
M transport_ empty 
(610.4  480) kg/pallet
 0.27 kg/litre
480 litres/pallet
The value to be utilised in the software can be now obtained by multiplying the transport mass
(1.27+0.27=1.54 kg/litre) by the covered distance (300 km, paragraph 4.5.2) which results
equal to 462 kg×km/litre. The module employed to model transportation burdens is the same
308
of the one utilised in the others bottled water scenarios: Transport, lorry >16t, fleet
average/RER, available in Ecoinvent.
The transport unit employed during the delivering transportation from local distributors to
consumers houses is instead the single crate of 12 bottles complete of caps, labels and
contained water, with a total mass of 14.6 kg and a specific mass of 1.22 kg/litre. During the
return trip an empty mass of 2.6 kg is instead transported which corresponds to a specific one
of about 0.22 kg/litre. According to the distance to be covered during the delivering trip (20
km, paragraph 4.10.2) the value to be considered is therefore equal to (1.22+0.22)kg/l×20
km=28.8 kg×km/litre. The transportation is modelled with the dataset Transport, lorry 3.516t, fleet average/RER.
The whole inventory is implemented in a new module, Bottled water, PET refillable, 1 litre,
at consumer, which by recalling all the modules described up to now models the upstream
burdens associated with the delivering of 1 litre of water by means of 1 litre refillable PET
bottles. The whole scenario is instead implemented in the module Waste prevention scenario
2B (refillable PET bottled water) which accounts for the burdens associated with treatments
of municipal wastes generated in this scenario as well as with the delivering of 152.1 litres of
water by means of 1 litre refillable PET bottles.
Table D.7 summarizes the major processes characterizing this scenario and the respective
magnitude through which they are included.
CHAPTER 5
RESULTS AND SENSITIVITY ANALYSIS
5.1 Results of the different modelling approaches
In this paragraph the results obtained by applying the different methodological approaches to
the life cycle modelling of the recycled PET bottled water scenario, of PLA composting and
of the glass refillable bottled water scenario are firstly briefly presented. The outcomes of the
methodology which assigns the worst environmental performances to the respective scenario
will be then applied in the comparison among all the investigated systems in paragraph 5.2,
according to a conservative approach.
First of all, as far as the recycled PET one-way bottled water scenario is concerned, it is
possible to notice from figure 5.1, how the closed loop approach assigns it higher
environmental impacts than the hybrid approach14, with respect to all the considered
indicators and especially for the CED. This because, as showed for example in figure 5.2 for
the CED indicator and in figure E.1 for the other ones, for the same impacts associated with
preforms manufacturing, much lower benefits are instead credited to the process of bottles
recycling when the closed loop approach is applied instead of the hybrid one. Indeed, when
this last approach is adopted, the fact of crediting to the system the avoided burdens of the
production of virgin PET granules in a quantity corresponding to the whole amount of
material recovered from recycled PET bottles, far outweighs the fact of having accounted for
the burdens either of the recycling process which takes place in the waste management system
or of the one which provides recycled PET granules for preforms manufacturing in the
upstream bottled water system. On the contrary, in the closed loop approach only the burdens
of the recycling process which provides the secondary raw material for preforms
manufacturing are considered, but also a lower amount of avoided virgin production burdens
are credited to the system itself, leading to overall higher impacts.
14
For a description of the differences between these two approaches see paragraph 4.6.
310
Chapter 5. Results and sensitivity analysis
Global warming
MJ eq./F.U.
500
439.7
336.2
250
0
Closed loop
approach
kg CO2 eq./F.U.
Cumulative energy demand
23.8
21.3
Closed loop
approach
Hybrid approach
20
10
0
Hybrid approach
Eutrophication
184.3
200
139.4
100
0
Closed loop
approach
g PO43- eq./F.U.
g Sb eq./F.U.
Abiotic depletion
15.3
15
11.3
10
5
0
Hybrid approach
Closed loop
approach
Hybrid approach
Figure 5.1: Impact indicators calculated for the recycled PET one-way bottled water scenario by applying the
two different typologies of modelling approach described in paragraph 4.6
Closed loop approach
255.6
250
MJ eq./F.U.
MJ eq./F.U.
250
150
50
-50
Hybrid approach
-24.5
255.6
150
50
-50
-150
-128.1
Preforms production
Preforms production
Recycling bottles and bundle film s
Figure 5.2: Contribution of the processes of preforms manufacturing and bottles recycling to the CED indicator
for the recycled PET one-way bottled water scenario modelled through the two different approaches described
in paragraph 4.6
Figure 5.3 shows the values of the impact indicators calculated for the PLA one-way bottled
water scenario, by applying the two different approaches proposed in paragraph 4.7.2 to
model composting of PLA bottles to which we refer here as the “process specific” and the
311
“PLA specific” approach, respectively. We briefly remember that in the process specific
approach all the process specific burdens associated with the traditional composting process
are assigned to PLA composting. On the contrary, in the PLA specific approach, PLA is
assumed to be composted together with traditional organic waste fractions in a share of 30%
and its composition is considered to define CO2 emissions (biogenic) and leachate generation.
Process specific consumptions of water, electricity and diesel are however assigned to PLA
composting as well.
Global warming
MJ eq./F.U.
587.8
586.6
600
400
200
0
Process specific
approach
kg CO2 eq./F.U.
30
PLA specific
approach
0
Eutrophication
209.4
g PO43- eq./F.U.
g Sb eq./F.U.
Process specific
approach
10
PLA specific
approach
200
100
0
Process specific
approach
27.4
20
Abiotic depletion
207.7
27.4
PLA specific
approach
40
36.6
37.1
Process specific
approach
PLA specific
approach
30
20
10
0
Figure 5.3: Impact indicators calculated for the PLA one-way bottled water scenario by applying the two
different typologies of approach described in paragraph 4.7.2 for the modelling of PLA composting
As it can be observed, the two approaches lead to very similar results for all the considered
indicators, even if the PLA specific one assigns slightly worse performances and therefore the
respective results will be utilised in the comparison among all the investigated scenarios in
paragraph 5.2.
To find the reasons at the basis of these small differences we have firstly to observe how, as
showed in figure 5.4, the traditional composting process is characterized by slightly negative
value of the CED and of the global warming indicators because, as showed in figure 5.5, the
312
benefits associated with the avoided production of peat and fertilizers are slightly greater than
the burdens associated with energy consumptions and treatment of residues. Therefore when
the PLA specific approach is applied, the impacts of the process specific consumptions
(electricity, diesel, leachate treatment) assigned to PLA composting are compensated by a
similar increase of the savings associated to the composting process of the organic waste
fraction constituting the remaining part of the compost pile in which PLA is introduced
(figure 5.6). This leads to an overall negligible increase of the impacts associated with PLA
composting process and therefore of the whole scenario. In particular, the CED indicator
changes from a slightly negative to a slightly positive value, while the global warming one
still remains slightly negative because CO2 emissions assigned to PLA degradation are of
1.0
0.482
0.5
0.0
-0.5
-1.0
-0.76
Global warming
kg CO2 eq./F.U.
MJ eq./F.U.
biogenic nature (figure 5.4).
0.00
-0.02
-0.04
-0.0431
-0.06
-0.08
-0.0761
Process specific approach
process specific approach
PLA specific approach
Figure 5.4: Contribution of the PLA composting process to the CED and the global warming indicators for the
PLA one-way bottled water scenario
313
3
Global warming
0.15
2.24
kg CO2 eq./F.U.
2
MJ eq./F.U.
0.134
1
0.083
0
0.0053
-0.57
-1
-2
-2.52
-3
0.054
0.05
0.0113
3.71E-04
-0.05
-0.0626
-0.15
-0.213
-0.25
Electricity and diesel consumption
Scraps landfilling & steel recycling
Direct emissions from composting
Leachate treatment
Fertilizers avoided
Peat avoided
Leachate treatment
Fertilizers avoided
Peat avoided
Figure 5.5: Contribution by sub processes to the CED and the global warming indicators for PLA composting
modelled through the process specific approach
Global warming
3
2.24
1
0.009
0
-1
-2
-1.7712
Leachate treatment
Composting organic waste
kg CO2 eq./F.U.
MJ eq./F.U.
2
0.2
0.134
0.1
0.00063
0.0
-0.1
-0.2
-0.177
Leachate treatment
Figure 5.6: Contribution by sub processes to the CED and the global warming indicators for PLA composting
modelled through the PLA specific approach
With regard to the value of the abiotic depletion indicator assigned to PLA composting, as
showed in figure E.2 it actually increases of one order of magnitude by utilising the PLA
specific approach with respect to the process specific one, but this growth results to be of
negligible entity on the performance of the whole scenario in view of the small contribution
of the composting process to the definition of the respective impact indicator (figure E.14). Its
increase must be read in view of the fact that the traditional composting process is already
314
characterized by a positive value of the indicator since, as showed in figure E.3, the burdens
associated with process energy consumptions are not totally compensated by the benefits of
the avoided production of peat and fertilizers. If we consider hence that with the PLA specific
approach, the burdens associated with the composting of 2.33 kg of organic waste are
assigned to the composting of 1 kg of PLA, which in turn requires energy, only an increase of
the indicator can be expected (figure E.4). The same considerations are also valid for the
eutrophication indicator with the exception that this remains of the same order of magnitude
(figure E.2) and that the major contribution to its definition for the traditional composting
process is given by putrescible residues landfilling and not by electricity generation (figure
E.3). In the PLA specific approach, its effect continues to dominate the one of leachate
treatment (figure E.4).
Finally, similar outcomes to those obtained for the recycled PET scenario are obtained for the
glass refillable one. Indeed, as showed in figure 5.7 and according to the reasons already
pointed out, the application of the closed loop approach to glass bottles and aluminium caps
life cycle results to be more burdensome than the use of the hybrid approach. This because in
view of exactly the same burdens associated with bottles and caps manufacturing by both
methods, much more lower credits are instead assigned to their recycling by the closed loop
approach, as showed for instance in figure 5.8 for the CED indicator, leading to the mentioned
conclusions.
The results obtained with this last method will be therefore employed during the scenarios
comparison in the next paragraph 5.2.
315
Global warming
481.7
437.6
kg CO2 eq./F.U.
MJ eq./F.U.
500
250
0
Closed loop
approach
30
26.2
10
0
Hybrid approach
Closed loop
approach
g Sb eq./F.U.
201.6
184.0
100
0
Closed loop
approach
Hybrid approach
Eutrophication
g PO43- eq./F.U.
Abiotic depletion
200
22.0
20
30
25.2
23.3
Closed loop
approach
Hybrid approach
20
10
0
Hybrid approach
Figure 5.7: Impact indicators calculated for the glass refillable bottled water scenario by applying the two
different typologies of modelling approach described in paragraph 4.10.1
Hybrid approach
Closed loop approach
50
120.7
52.2
0
-15.6
-36.1
-50
MJ eq./F.U.
MJ eq./F.U.
100
90
40
-10
120.7
52.2
-40.2
-55.5
-60
Bottles production
Bottles production
Caps and labels production
Recycling bottles
Recycling caps & incin. labels
Recycling bottles
Figure 5.8: Contribution of bottles and caps production and recycling processes to the CED indicator for the
glass refillable bottled water scenario modelled through the closed loop and the hybrid approach
316
5.2 Base case results and remarks
5.2.1 Waste generation
Prior to examine the results of the assessment, we present as a first term of comparison for all
the investigated delivering systems, the amount of municipal waste generated by each of
them, as reported in table 5.1. The amount of sludge generated by the tap15 surface water
system is also reported for completeness.
Table 5.1: Amount of waste generated in all the investigated scenarios
One-way BW1
scenarios
4.1
2
Glass refillable
BW1 scenario
2
7.91
PET refillable
BW1 scenario
kg/inhabitant/year
2
1.44
TW1 scenario
(groundwater)
0.5
3
TW1 scenario
(surface water)
Sludge: 0.0265
(21.6)4
Other: 0.00865
Total: 0.0356
g/litre of delivered water
27
52
9.47
3.3
Sludge: 0.174
Other: 0.0565
Total: 0.23
1: BW: Bottled Water; TW: Tap water.
2: The values reported include the contribution either of primary or of secondary packaging.
3: The value refers to the waste generated by the annual substitution of the activated carbon filter of the domestic
depurator. The amount of waste generated by the use of the glass jug is instead not reported because, other than
of negligible entity, it is a function of consumers behaviour rather than a specific feature of the scenario.
4: The amount of sludge reported in brackets is calculated considering the average population served by the
Anconella plant (about 500,000 inhabitants) while the other value is defined starting from the specific production
(0.174 g/l) by considering that 152.1 litres/inhabitant/year have to be delivered in each scenario.
5: This value refers to the waste generated by the periodical substitution of consumable materials of the
depuration system utilised for water delivering from public fountains (polypropylene pre-filter and activated
carbon filter).
6: The amount of waste generated by the use of glass bottles is not reported because it is a function of consumers
behaviour rather than a specific feature of the scenario.
As it can be observed, the scenario based on the use of refillable PET bottles is the least waste
generating one among bottled water scenarios, whatever is the material considered (virgin
PET, recycled PET or PLA), and an actual prevention in terms of mass is achieved with
respect to one-way scenarios as well as to the glass refillable scenario.
The use of refillable glass bottles instead does not imply an actual prevention in terms of mass
of generated waste because of the higher density of glass itself with respect to PET. As
15
For brevity, the scenario/system that foresees the consumption of public network water of surface origin
delivered from public fountains is indicated in this chapter as the “tap surface water scenario/system”, even if
actually water is not directly consumed from the tap.
317
anticipated in paragraph 4.10.1, in this case it is the number of items that eventually become
waste that is reduced, but obviously not their total mass. This seems however to be still
compatible with the definition of waste prevention given by the last Waste Framework
Directive (European Parliament and Council, 2008), which defines as preventive those
measures that reduce the amount of generated waste, without specifying if it deals with mass,
volume, or number of items. It can be however presumed that the definition implicitly alludes
to the mass, even if it is not explicitly mentioned.
Definitely negligible is the amount of municipal solid waste generated by the two cases of use
of public network water, which is limited to the annual or biannual substituted consumable
materials utilised by the respective water refinement systems. In addition, also the waste
represented by the containers employed to conserve water should be considered but their
amount appears to be a function of consumers behaviour rather than a specific feature of the
investigated systems and is therefore not reported. However it can be assumed to be of
negligible entity in view of the long life span which generally characterizes these objects. On
the contrary, we have considered meaningful to report the amount of sludge generated during
surface water purification which is the waste flow produced in larger quantities by such a
system. Nevertheless it results of one or two orders of magnitude lower than the amount of
waste generated by bottled water systems when expressed in mass per litre of delivered water,
and two orders lower when expressed on annual basis. By looking at table 5.1, it is therefore
possible to notice how, with regard to waste generation, both public network water systems
appears to be preferable than bottled water ones.
Note that the annual amount of sludge generated by the Anconella plant calculated on the
basis of the number of citizens served by the plant itself, is considered less reliable than the
amount calculated starting from the specific production, which was employed in the
comparison. Indeed, despite the volume of delivered water is a function of the number of
served citizens, this relation could not be linear at all.
5.2.2 LCA results
Figure 5.9 shows the comparison among the eight investigated scenarios with respect to the
four considered impact indicators. Their values are expressed with reference to the functional
unit assumed for the present study which we remember being “the management of the amount
318
MJ eq./F.U.
600
587.8
400
468.6
546.8
439.7
481.7
365.8
307.8
200
50.0
0
kg CO2 eq./F.U.
Virgin PET
one-w ay
R-PET onew ay
PLA onew ay
composting
GLASS
ref illable
PET refillable
Tap
Tap surf ace
groundw ater
w ater
Global warming
30
20
PLA onew ay
incineration
78.4
24.8
23.8
27.4
25.0
26.2
20.7
16.5
10
2.1
0
Virgin PET
one-w ay
R-PET onew ay
PLA onePLA onew ay
w ay
composting incineration
GLASS
refillable
PET refillable
3.8
Tap
Tap surf ace
groundw ater
w ater
g Sb eq./F.U.
Abiotic depletion
200
196.6
184.3
209.4
190.3
201.6
100
145.8
126.8
25.9
31.8
0
g PO43- eq./F.U.
Virgin PET
one-w ay
R-PET onew ay
PLA onePLA onew ay
w ay
PET ref illable
Tap
Tap surf ace
groundw ater
w ater
Eutrophication
40
37.1
30
35.9
20
10
GLASS
refillable
25.2
16.4
10.3
15.9
15.3
0.94
0
Virgin PET
one-w ay
R-PET onew ay
PLA onew ay
composting
PLA onew ay
incineration
GLASS
ref illable
PET refillable
2.3
Tap
Tap surf ace
groundw ater
w ater
Figure 5.9: Impact indicators calculated for all the investigated scenarios (the dotted area in the tap surface
water bar specifies the contribution given by water transportation by car)
319
of (municipal) waste annually generated from the consumption of drinking water by one
Italian citizen”.
In order to avoid misleading interpretation of the results, the contribution given by the use of
a private car for water transportation from public fountains to consumers houses is explicitly
indicated in their presentation (dotted area of the bars representing the surface water scenario)
because of its important role in defining the overall potential impacts of the tap surface water
scenario.
5.2.2.1 Remarks about tap water scenarios
A first important remark can be made with regard to the definitely better environmental
performances of the tap groundwater scenario for all the impact indicators considered in this
study, even when water quality is improved through a domestic depuration treatment and
when life cycle impacts associated with use and washing of a reusable container (glass jug in
this case) are accounted for. In particular this system implies potential impacts which at most
reach the 13% of those associated with the use of one-way virgin PET bottles. Therefore,
beyond reducing waste generation, it results actually more environmentally sustainable than
bottled water systems, leading to meaningful potential savings of energy, greenhouse gases
emissions and resources.
Moreover, if we look at the contribution given by the major sub processes (figures 5.10 and
E.5), it is possible to notice how meaningful roles are held by washing of the reusable jug and
by its life cycle rather than by water treatment and delivery to users, which never exceeds 5%
of the total. In particular, jug washing is at the second place after domestic purification with
regard to CED, abiotic depletion and eutrophication indicators, while it occupies the first
place for the global warming one; the processes associated with jug life cycle are instead at
the third place for all the considered indicators. This means that the overall impacts of such a
system could be even lower if jug was only rinsed between one use and the other rather than
washed in a dishwasher, or if a life span longer than one year was assured to the jug itself,
like it probably actually happens in true life. This precautionary value was indeed assumed in
the inventory according to an absolutely conservative approach.
With the only already mentioned exception of global warming, the major contribution to the
impact indicators is given by domestic purification of water for which, in turn, the primary
role is held by the use of activated carbon followed by electricity consumptions and treatment
320
of discharged water (table E.1). This sequence is valid for all the considered indicators except
for global warming, in which the roles of activated carbon life cycle and electricity are
inverted. It must be however noticed that the contribution given by activated carbon may be
overestimated since its amount was allocated to 1 litre of water on the basis of the volume to
be delivered under each scenario (152.1 litres per year), while actually it could be able to deal
with an higher annual volume of water.
MJ eq./F.U.
22.9
20
18.2
10
6.54
2.34
0
Global warming: contribution by subprocesses (TAP GW scenario)
kg CO2 eq/F.U.
Cumulative energy demand:
contribution by sub processes (TAP
GW scenario)
1.5
1.1
1.0
0.56
0.5
0.28
0.14
0.0
Domestic purification
Jug washing
Jug washing
Glass jug life-cycle
Water treatments & network pumping
Figure 5.10: Contribution of the major sub-processes to the CED and the global warming indicators calculated
for tap groundwater scenario
200
100
62.2
15.3
0
0.89
Global warming: contribution by subprocesses (TAP SW scenario)
kg CO2 eq/F.U.
MJ eq./F.U.
contribution by sub-processes (TAP
SW scenario)
287.4
20
16.9
15
10
5
0
2.9
0.90
0.053
Transp. fountains-consumer house
Glass bottles life-cycle
Quality improvement (public fountains)
Water treatments & pumping
for tap surface water scenario
321
The same considerations concerning the better environmental performances can be translated
also to the surface water system if a car is not employed for water transportation from public
fountains to consumers houses. As it can be seen, its use gives indeed a very important
contribution in increasing the values of all the considered indicators to levels comparable with
those of bottled water systems, even if actually higher than those pertaining to the PET
refillable system only (except for the eutrophication indicator in respect of which it is slightly
better).
These results however must be read in view of the fact that the burdens of the consumer trip
were totally allocated to the transported water because it was considered to be only aimed at
water transportation. The respective burdens were therefore only shared among the 9 litres of
water that were assumed to be drawn at the fountain even if it is likely that the trip is made
also for other purposes (such as going to or coming back from the working place) and a
further allocation would be needed. For instance, a 50% allocation factor could be employed
to model the fact that the trip is made for a further purpose other than for water transportation.
This possibility will therefore be taken into account in the sensitivity analysis (paragraph
5.3.4).
By looking at figures 5.10, 5.11, E.5 and E.6 it is actually possible to notice how, if the
contribution of the transportation by car is excluded, the reasons for all the impact indicators
characterizing the surface water system to be slightly higher than those pertaining to the
groundwater one, appear not associated to an higher contribution given by water treatment
and network pumping. Rather they seem associated with the more impacting life cycle of the
9 reusable glass bottles with respect to that of the sole reusable glass jug and of its washing as
well as, in the case of global warming, with the slightly higher burdens of public water quality
improvement with respect to domestic depuration. Indeed, with the exception of this
indicator, domestic depuration appears at a first sight more burdensome than water quality
improvement and its delivery from public fountains.
These outcomes have however to be interpreted with caution. First of all, the impacts
associated with water treatment and pumping in both tap water scenarios are actually also a
function of the efficiency of the domestic depurator or of the public improving quality system,
which defines the amount of already treated water (with the respective burdens) which has to
be supplied in order to deliver 1 litre of further purified water. Therefore the fact that the
domestic depuration system was assumed to be characterized by a recovery efficiency of
about 33.3%, while the public system by an average efficiency of about 92% widely
322
influences the results. In particular if we look at the life cycle impacts associated with the sole
initial purification and delivering of 1 m3 of water of the two analysed systems (figure 5.12) it
is possible to notice how actually the groundwater one is characterized by slightly lower
impacts with respect to the surface water system for all the considered indicators, though
always comparable. It is therefore clear how the lower efficiency which characterizes the
domestic depurator system hides this aspect.
4
2
Global warming
kg CO2 eq./m 3
MJ eq./m 3
5.4
5.1
0
0.315
0.2
0.0
Groundwater system
Groundwater system
Surface water system
Eutrophication
2.17
2.24
2
1
g PO43- eq./m 3
Abiotic depletion
g Sb eq./m 3
0.320
0
0.10
0.092
0.10
0.05
0.00
Groundwater system
Groundwater system
Figure 5.12: Comparison of the impact indicators calculated for the purification and the delivering of 1 m3 of
groundwater and surface water
More in detail, we remember that the groundwater treatment and delivering system is
characterized by an higher specific consumption of electricity with respect to the surface
water system (0.485 kWh/m3 against 0.382 kWh/m3) and therefore, as it can be observed in
figures 5.13, 5.14, E.7 and E.8, its primary contribution to all the impact indicators actually
slightly decreases from the former to the latter system.
The mentioned decrease is though balanced by the raising of the contribution associated with
the use of chemicals, which is wider in the surface water system than in the groundwater one,
as well as by the slight increase of that given by the life cycle of activated carbon. Indeed,
despite its specific consumption is of the same order of magnitude for both systems, the
323
higher losses during the reactivation of the carbon utilised by the surface water system imply
an higher amount of virgin carbon to be produced and activated. However it holds a
secondary role in defining the overall impact of the two systems. The additional consumption
of sand, as well as the need of sludge disposal in landfill, result instead of negligible entity.
Sludge disposal is indeed actually limited only to about 10% of the whole generated amount,
being the rest employed for other applications such as for embankments or for road subgrades
(without any previous treatment). It is finally possible to notice how infrastructures play a
secondary role in defining the overall impacts of the groundwater system and comparable
with that held by the use of activated carbon and hypochlorite, in view of the fact that the
respective burdens are averaged on their whole life span. The contribution of infrastructures
in the surface water system is instead only fictitious since, in reason of their marginal role,
they were assumed to be the same as the groundwater system, only to allow a fair comparison.
Global warming: contributions to
water treatment and delivering
4
2
0.34
0.058
0.0019
0
0.28
kg CO2 eq/m 3
MJ eq./m 3
contributions to water treatment
and delivering
4.73
0.2
0.031
0.0
0.0023 9.50E-05
Electricity treatment & pumping
Infrastructures
Infrastructures
Activated carbon life-cycle
Hypochlorite prod.
Hypochlorite prod.
Figure 5.13: Contributions of the major sub-processes to the CED and the global warming indicators calculated
for the treatment and the delivering of 1 m3 of groundwater
324
Cumulative energy demand: contributions to water
treatment and delivering
3.73
MJ eq./m 3
4
2
1.25
0.34
0.080
0.0039
0.0035
0
Chemicals prod.
Infrastructures
Sand production
Sludge disposal
Global warming: contributions to water treatment and
delivering
kg CO2 eq/m 3
0.22
0.2
0.1
0.064
0.031
0.0025
0.00025
0.00012
0.0
Chemicals prod.
Infrastructures
Sand production
Sludge disposal
for the treatment and the delivering of 1 m3 of surface water
Also the higher impacts that in the whole scenarios result associated with domestic depuration
with respect to public water quality improvement for the CED, abiotic depletion and
eutrophication indicators (figures 5.10, E.5 and E.6) need to be interpreted with caution. If we
look indeed at the major contribution to the life cycle impacts of the processes of domestic
depuration or public quality improvement (Table E.1 and E.2), it is possible to notice how the
reason for the higher impacts of the domestic treatment is not associated with a more intense
use of electricity, whose specific consumption actually resulted lower than the case of public
quality improvement, where water is also refrigerated (2.63×10-3 kWh/litre against 0.01
kWh/litre respectively). Rather they seems to be associated to the higher contribution given
by the use of activated carbon, whose specific consumption instead resulted higher for the
325
domestic treatment with respect to public improvement (0.0033 kg/litre against 4.17×10-5
kg/litre). But as already pointed out above, the higher values obtained for the domestic
treatment find their reason in the fact that the mass of the filter was allocated on the basis of
the 152.1 litres of water which are annually consumed in each scenario, while the mass of the
filter of the H2O PLUS system on the basis of the average volume of water actually delivered
by public fountains during the 6 months of the carbon life span (about 360,000 litres).
Therefore the results of the present study does not allow and are not aimed at the explicit
identification of the best option for water quality improvement but only of the best performing
water delivering system as a whole.
5.2.2.2 Remarks about refillable bottled water scenarios
As far as bottled water systems are concerned, the PET refillable one appears the most
preferable from an environmental point of view with respect to all the considered indicators
except for the eutrophication, for which it is characterized by a value comparable with those
of PET one-way systems. However, the most important contribution to this last indicator is
not given by the use of detergents during bottles washing as one could be expect, but rather by
the increased burdens associated with transportation (figure E.10) and in particular by
nitrogen oxides airborne emissions (NOx). This because in this system an higher mass has to
be transported during the roundtrip with respect to one-way systems either because of the
higher mass of bottles or because also crates with empty bottles need to be transported back
together with empty pallets during the return trip. Despite the negligible exception of the
eutrophication, the implementation of a refilling system based on PET bottles appears another
case in which other than waste reduction, also more environmental sustainability is achieved
with respect to the use of one-way bottled water systems, at least with regard to the indicators
considered in the present study.
The reasons at the basis of these performances can be clarified by comparing the contribution
given by the major sub-processes to the overall impacts of this scenario to those, for instance,
of the virgin PET one-way scenario which can be considered as the reference system of this
study. They are presented in figures 5.15 and E.9 for the virgin PET one-way scenario and in
figures 5.16 and E.10 for the PET refillable scenario.
326
Cumulative energy demand: contribution by sub-processes (Virgin PET
one way scenario)
388
MJ eq./F.U.
350
250
150
107.7
50
36.1
30.8
29.5
17.4
7.6
-50
-20.5
-150
-128.1
Preforms production
Transport. bottling plant-retailers
Secondary packaging life-cycle
Transport. retailers consumer-house
Transport packaging life-cycle
Incin. bottles, caps, labels and films
Recycling bottles and bundle films
Global warming: contribution by sub-processes (Virgin PET one way
scenario)
14.8
kg CO2 eq/F.U.
15
10
6.3
5
1.8
1.4
1.1
1.0
0.88
0.59
0
-3.0
-5
Preforms production
for virgin PET one-way bottled water scenario
327
Cumulative energy demand: contribution by sub-processes (PET
refillable scenario)
151.4
MJ eq./F.U.
150
100
69.4
60.2
50
24.5
20.8
20
12.7
6.34
0
-27.1
-50
-30.5
Transport. bottling plant-local distributors
Bottles production
Transport. local distributors-consumer house
Bottles washing
Secondary packaging-life cycle
Recycling bottles
Global warming: contribution by sub-processes (PET refillable
scenario)
kg CO2 eq/F.U.
10
5
8.8
2.6
1.8
1.5
1.2
1.2
0.54
0.12
0
-0.38
-0.75
-5
Bottles production
Bottles washing
Recycling bottles
for PET refillable bottled water scenario
As it can be noticed, the most important roles are held, for both systems and for all the
considered indicators, by preforms/bottles manufacturing (in particular of resin) and the
respective end of life process, as well as by the roundtrip transportation of water between
bottling plants and retailers or local distributors. Their major importance is probably
328
ascribable to the relevance of bottles mass flow with respect to those of the other inputs
materials and to the meaningful transport distance in which bottled water is involved. More
precisely, while transportation sits at the second place with regard to the PET one-way
system, it shifts to the first place for the PET refillable system for the same considerations
concerning the higher mass to be transported during the roundtrip. On the contrary,
manufacturing of reusable PET bottles, even if characterized by an higher mass, is at the
second place with a meaningful reduction of the associated impacts compared to the one-way
system. Analogously, also the savings of the respective recycling process decrease, but the
result is an overall less burdensome life cycle. All the other involved processes are instead of
secondary importance. In particular, the use of reusable crates as secondary packaging
material appears slightly less burdensome than the use of disposable films (Table E.3).
Analogously the use of the only plastic ligature and the absence of cardboard interlayer to
build up the transport unit appear slightly better with respect to the use of stretch film, despite
a lower amount of water is loaded on the pallet (Table E.4). On the contrary, the use of
heavier caps (3.2 g against 1.61 g) contributes to a slight increase of the impacts of their
whole life cycle (Table E.5). Also the impacts of the delivering trip from local distributors to
consumers houses increase, according to the longer distance (20 km) which was considered to
be travelled with respect to one-way scenarios (10 km). Finally the impacts associated with
bottling plant operations slightly raise up since they include washing of bottles. However,
with the only already mentioned exception of the eutrophication indicator, the overall result is
a decrease of the impacts characterizing the refillable PET bottled water scenario. This
especially because the 1 order of magnitude decrease of the burdens associated with the lower
amount of bottles to be manufactured is much higher than the increase of transportation
burdens which remain of the same order of magnitude. On the contrary, for the eutrophication
the decrease of bottles life cycle burdens is compensated by the increase of those pertaining to
both the transportation stage and bottles washing, leading to obtain similar values of the
indicator.
We have finally to remember that the decision to assume the size of 1 litre for refillable PET
bottles was taken during the inventory stage in order to allow a fair comparison with the glass
refillable scenario in which the maximum available volume of bottles just corresponds to 1
litre. However we have recognized that also 1.5 litres refillable PET bottles are available in
the market for mineral water and carbonated soft drinks delivering (UBA 2000a; 2000b;
IFEU, 2010), and therefore higher benefits could potentially be expected through the
329
implementation of such a system with respect to one-way bottled water. This statement
however should be verified by employing a life cycle perspective.
The glass refillable scenario is characterized by performances comparable with those of oneway systems and, in particular, placed between those of PET one-way systems (lower bound)
and PLA one-way systems (upper bound). Through a more comprehensive look at the
contribution given by major sub processes to the overall impacts of the scenario (figures 5.17
and E.11), it is possible to notice how, for all the indicators, the impacts of water
transportation from bottling plants to local distributors are greater than for the PET scenario
because of the higher mass of bottles. The impacts associated with bottles life cycle are
instead lower than those pertaining to one-way PET bottles, even if to a lower extent with
respect to the reductions registered for the refillable PET scenario. Other unbalanced minor
contributions are those given by transportation from distributors to consumers and by bottles
washing, which in this case is more energy intensive with respect to the PET refillable
scenario.
A direct consequence of the fact that transportation impacts are much higher than those of
one-way systems, is that they are expected to respond to a reduction of distances by lowering
in a greater extent with respect to one-way systems themselves. Therefore the outcomes
obtained through the values employed in the base case inventory need to be checked for lower
distances to be travelled, as will be done in the sensitivity analysis in paragraph 5.3.6.
Furthermore another important factor potentially influencing the results is the number of uses
attributed to glass bottles, which defines the impacts associated with their manufacturing,
which is the second most important contributor to the overall impacts of the system, after the
transportation stage. In the inventory a value of 10 uses was indeed assumed for bottles,
according to the fact that it was directly provided by the investigated realities, but other
sources which consider an higher number of uses are found and sensitivity will be performed
on this parameter according to these last provided values.
Some further remarks can also be made with regard to the fact that the use of aluminium caps
results advantageous, from an environmental point of view, if they are recycled at the end of
their useful life, with respect to the use and the incineration of HDPE caps, as in the case of
one-way scenarios, or to the recycling of heavier HDPE caps, as in the case of the PET
refillable scenario (Table E.5). Moreover slightly worse but however similar performances
characterize instead the life cycles of both secondary and transport packaging materials
330
utilised in this scenario with respect to the PET refillable one (Table E.3 and E.4). This
because HDPE crates and pallets are slightly heavier than those utilised for refillable PET
bottles. Indeed the increase of the volume of transported water does not compensate the
increase of the mass of pallet materials, which are heavier than those of standard EUR-EPAL
pallets employed in one-way and PET refillable systems.
331
Cumulative energy demand: contribution by sub-processes (GLASS
refillable scenario)
236
MJ eq./F.U.
200
120.7
100
52.2
45.2
38.7
20
13.8
0
6.7
-15.6
-36.1
-100
Bottles production
Bottles washing
Recycling bottles
Global warming: contribution by sub-processes (GLASS refillable
scenario)
kg CO2 eq/F.U.
15
13.7
10
5
6.4
2.8
2.5
2.3
1.2
0.59
0.12
0
-1.6
-5
Bottles production
Bottles washing
Recycling bottles
-1.9
Figure 5.17: Contribution of the major sub-processes to CED and the global warming indicators calculated for
glass refillable bottled water scenario
332
5.2.2.3 Remarks about one-way bottled water scenarios
In the comparison among the one-way systems themselves, the utilisation of 50% recycled
PET bottles is characterized by slightly but not dramatically better performances than the use
of virgin PET or PLA bottles with respect to all the considered indicators. Therefore, despite
the effort of employing recycled material together with virgin raw material for bottles
manufacturing is appreciable, it seems however that it does not lead to those higher levels of
savings of energy, resources and greenhouse gases achievable by utilising a refilling system
based on PET bottles. By looking at figures E.12 and E.13, it is possible to notice how the
slightly better performances of this scenario are associated with a less impacting life cycle of
bottles (PET resin production and recycling) with respect, for instance, to the use of virgin
PET bottles, because of the lower impacts associated with providing secondary raw material
compared to virgin one.
The use of PLA bottles appears instead to have the worst performances compared to the other
one-way scenarios with respect to all the considered indicators, except for the abiotic
depletion one, which is slightly better than that characterizing the virgin PET scenario when
incineration is foreseen as end of life option for PLA bottles. The reasons at the basis of these
results can be found by comparing the contribution of the single sub processes to the overall
value of the indicators associated with the PLA scenarios (figure 5.18, 5.19, E.14 and E.15)
with those of the other one-way systems.
333
Cumulative energy demand: contribution by sub-processes (PLA one
way to composting scenario)
371.6
MJ eq./F.U.
350
250
150
107.7
36.1
50
29.5
26.6
17.4
7.6
0.48
-1.1
-50
-8.3
Preforms production
Transport. retailers-consumer house
Composting bottles
Recycling bundle films
Incin. caps, labels and films
Global warming: contribution by sub-processes (PLA one way to
composting scenario)
kg CO2 eq/F.U.
20
15.4
15
10
5
6.3
1.6
1.1
1.0
0
0.88
0.59
0.52
0.080
-0.043
-5
Preforms production
Composting bottles
for PLA to composting bottled water scenario
334
Cumulative energy demand: contribution by sub-processes (PLA one
way to incineration scenario)
371.6
MJ eq./F.U.
350
250
150
107.7
36.1
50
29.5
26.6
17.4
7.6
-1.1
-50
-8.3
-40.6
Preforms production
Incineration PLA bottles
Global warming: contribution by sub-processes (PLA one way to
incineration scenario)
kg CO2 eq/F.U.
20
15.4
15
10
5
6.3
1.6
1.1
1.0
0.88
0.59
0.52
0.080
0
-2.4
-5
Preforms production
for PLA to incineration bottled water scenario
First of all, with regard to the CED indicator it is possible to notice how even if it appears that
a slightly lower energy consumption is associated with PLA preforms manufacturing
compared to PET ones (371.6 MJ eq. against 388 MJ eq.) thanks to the lower energy intensive
process of virgin resin production, much more lower are the benefits associated with PLA
335
bottles composting or incineration with respect to the recycling of PET bottles. In particular,
composting actually gives a slightly positive contribution to the indicator for the reasons
already pointed out in paragraph 5.1, while PET recycling gives a negative contribution since
it is credited of the avoided production of virgin PET granules. The result is therefore an
overall increase of the value of the indicators. Note that the energy savings of about 13.5%
attributed to bottling plant operations when PLA preforms are utilised, are masked by the
relative small contribution of this life cycle stage to the overall impacts if compared to resin
manufacturing or transportation.
With regard to the global warming indicator, besides the lower benefits associated with both
the end of life options considered for PLA bottles, also a slight increase of the impact
associated with PLA resin production with respect to the production of PET resin contributes
to increase the overall value of the indicator. In particular CO2 emissions associated with
generation of electricity and heat from natural gas hold the major role in defining the
contribution to global warming associated with PLA production.
Also the appreciable potential savings of fossil resources which characterize the use of PLA
with respect to PET are vanished by the reduced benefits associated with the considered end
of life options. Finally, the eutrophication indicator for PLA scenarios results to be
abundantly greater than that associated with the other one-way scenarios in view of the wide
use of fertilizers for maize cultivation.
On the basis of these considerations, composting or incineration of PLA bottles do not appear
therefore to be the most sustainable end of life options and, more in general, it seems that the
sustainability of bio-plastics must be evaluated carefully when such end of life treatments are
applied. Moreover we remember that in the present study PLA granules were assumed to be
transported along average European distances to the preform manufacturing site, while
actually they could be involved in a transoceanic transportation from the world’s largest
manufacturing plant sited in Nebraska (USA).
It is worth to notice that recent pilot experiences have also demonstrated how a potential
alternative end of life option for PLA products could be their chemical recycling by means of
depolymerization through hydrolysis to lactic acid monomers. These lasts would be then
purified and directly utilised for industrial applications as detergents or green solvents or
repolymerized in new PLA resin, whose final quality has however still to be improved
(NatureWorks, 2011; Loopla-Galactic, 2011). Considering such an end of life option for PLA
bottles might probably lead to completely different conclusions with respect to those obtained
336
by considering composting or incineration, but in view of its pilot nature no data are found in
its respect.
Some further general considerations can also be made with regard to the comparison of the
contribution of the major sub processes to the impacts of all the one-way bottled water
systems.
As already noticed, the most important positive contributions are represented, for all the
considered indicators, by preforms manufacturing and secondly by transportation between
bottling plants and retailers, except for the eutrophication indicator of the recycled PET
scenario, for which the two roles are inverted in reason of the less burdensome process of
secondary PET granules supplying with respect to both virgin PET and virgin PLA granules
manufacturing. As earlier pointed out, the major importance of these two processes is also
ascribable, respectively, to the relevance of bottles mass flow with respect to that of the other
inputs materials and to the meaningful transport distance in which bottled water is involved.
Among bottling plant operations the most relevant role is held by electricity consumptions
while only very marginal is the one associated with lubricating oil life cycle and to washings
of filler machine, also with respect to the eutrophication indicator, despite the use of
detergents in this stage (Table E.6). Consumptions of lubricating oil and detergents is indeed
of minimal entity (table 4.17).
Contrarily to the surface water scenario, the car roundtrip transportation from retailers to
consumers houses holds only a limited impact in reason of the fact that its burdens were
allocated among all the transported items and not only to water.
The most evident contribution in terms of savings is represented by PET bottles recycling,
especially for the virgin PET scenario and by PLA bottles incineration in the respective
scenario. In the PLA composting scenario, it is instead represented by the incineration of
caps, labels and films, even if for a small extent. Composting of bottles results instead to be
substantially environmentally neutral, for the reasons already pointed out in paragraph 5.1.
5.2.2.4 Water consumptions
A last important remark can be done with regard to water consumptions. In particular we have
recognized that network losses may potentially represent a weak point of the performances of
tap water systems by implying the drastic increase of the respective consumptions. Indeed, if
337
it is true that the case of the aqueduct of the city of Milan investigated in this study represents
a virtuous system in which only about 11% of losses takes place, it is even true that other
Italian realities are characterized by much worse performances. An extreme example is the
already mentioned case of the Acquedotto Pugliese which during 2007 has registered a
percentage of losses equal to 50% of the volume actually delivered (Metropolitana Milanese,
2010). According to these considerations, we have decided to try to obtain some general
indications concerning the magnitude of water consumptions associated with the investigated
scenarios, on the basis of the values calculated through SimaPro, which are presented in
figure 5.20.
For their interpretation we have however to remember that first of all the consumptions
attributed to the bottling plant during the inventory stage are only rough estimates, since they
are not monitored by the examined company. Moreover network losses assigned to the
surface water system are the same of those registered by Metropolitana Milanese for the
aqueduct of Milan because of the lacking of specific information for that specific reality.
Finally only the internal consumptions of the Anconella plant are known but not as much
those occurring at the various treatment stations at the service of the aqueduct of Milan, which
were therefore not included in the analysis. They are however estimated not to be meaningful
by the company.
Water consumptions
80
75.9
57.0
m3/F.U.
60
40
51.3
56.8
49.1
37.8
20
34.8
11.3
11.4
0
Virgin PET R-PET one- PLA one- PLA oneone-way
way
way
way
GLASS
refillable
PET
Tap
Tap surface
refillable groundwater
water
Figure 5.20: Water consumptions calculated for the investigated scenarios (the dotted area in the tap surface
water bar specifies the contribution given by water transportation by car)
As it can be noticed, despite network losses and the high rejection rate of the domestic
depurator, the groundwater system seems to be actually characterized by lower consumptions
338
of water compared to all bottled water systems. The same would be valid also for the surface
water system if a car was not employed for water transportation. The respective consumptions
are mainly associated with the use of electricity generated by at-run-of-river hydropower
plants by the subsidiary processes included in the life cycle of the passenger car
(manufacturing and maintenance of the car and road construction, operation and
maintenance).
5.3 Sensitivity analysis
5.3.1 Introduction
Sensitivity analysis is conducted on two typologies of input parameters:
1) those which were arbitrarily assumed during the inventory stage and which are
resulted or are expected to have a meaningful effect on the outcomes of the analysis,
in particular:

percentage of the transportation burdens of one-way bottled water from retailers to
consumer house allocated to the water itself, which in the present study depends
on the number of items contemporarily transported (variations of this parameter
also implicitly include possible variations of transportation distance);

percentage of the dishwashing burdens allocated to the reusable glass jug in
groundwater scenario (which in this study are a function of the number of items
contemporarily washed) and its frequency of washing;

transportation distance of water from public fountains to consumers house
(variations of this parameter also implicitly include possible variations of the
volume of transported water or of the percentage of the burdens allocated to the
trip).

typology of container employed to conserve water in the surface tap water
scenario.
2) those more reliable parameters which are however subject to high variability, or for
which different values from those considered in the inventory are provided by other
sources, in particular:

339
transportation distance of one-way bottled water between the bottling plants and
local retailers and,

number of uses considered for refillable glass and PET bottles.
Sensitivity is conducted with respect to all the considered impact indicators and those affected
by meaningful changes will be reported and discussed in the rest of the paragraph. Moreover,
the results will be finally combined in order to define the upper and the lower bound of the
impacts associated with all the investigated scenarios.
5.3.2 Allocation of consumer purchasing trip burdens (one-way scenarios)
Even if the volume of water transported by one-way bottles during the purchasing trip defines
the burdens to be associated to 1 litre of transported water, a further allocation of these
burdens needs to be made to account for the fact that more than one product can be purchased
at the same time. This allocation can be carried out, for example, according to the mass, the
economic value or the total number of purchased items. Just this last option was chosen in
first instance during the inventory, by considering that one 6×1.5 litres bottles bundle is
purchased as a part of a whole amount of 30 items at any time. Therefore 1/30 (3.33%) of the
overall burdens associated with covering with a car the considered distance (10 km in the
present inventory) were assigned to 1 bundle. This value were finally reported to 1 litre of
water by considering that the bundle contains 9 litres of water.
Since the choice of the allocation factor was purely arbitrary, possible variations of this
parameter are considered in the present sensitivity analysis, also in order to indentify the
extent to which consumer behaviour can affect the performances of one-way systems.
The results are therefore further calculated using both a 1/60 (1.67%) and a 100% allocation
factor, representing respectively the case in which 60 items or the sole 6-bottles bundle are
contemporarily purchased.
Note that utilising these values has respectively the same effect of halving (5 km) or
multiplying by 30 the transport distance, when the allocation factor is maintained at 3.33%
and therefore sensitivity is not conducted for this parameter.
The results obtained for the four considered indicators are reported in figures 5.21 and E.16,
as well as in tables 5.2. and E.7.
340
973.6
MJ eq./F.U.
1000
944.8
1092.9
.6
1051.9
800
587.8
600
400
468.6
459.8
439.7 579.1
431.0
546.8
538.1
481.7
365.8
307.8
200
50.0
0
w ay
PLA onew ay
compost.
PLA onew ay incin.
GLASS PET refillable
Tap
Tap surface
ref illable
groundw ater w ater
Global warming
kg CO2 eq./F.U.
60
54.5
53.4
57.0
54.7
50
40
30
20
24.8
24.3
23.8
23.3
27.4
26.9
25.0
24.5
26.2
20.7
16.5
10
2.1
0
w ay
PLA onew ay
compost.
PLA onew ay incin.
GLASS
ref illable
PET ref illable
Tap
Tap surf ace
groundw ater w ater
Figure 5.21: Results of the sensitivity on the allocation of consumer purchasing trip burdens on the CED and
the global warming indicators in the comparison among the investigated scenarios
341
Table 5.2: Results of the sensitivity on the allocation of consumer purchasing trip burdens on the CED and the
global warming indicators for the interested scenarios
Virgin PET
one-way
Base case
(purchasing of 30 items)
MIN impact
% min
MAX impact
(purchasing of only water)
% max
Base case
MIN impact
% min
MAX impact
% max
CED (MJ eq./F.U.)
R-PET PLA one-way
one-way
compost.
PLA one-way
incin.
468.6
439.7
587.8
546.8
459.8
431.0
579.1
538.1
-1.9
973.6
-2.0
944.8
-1.5
1092.9
-1.6
1051.9
107.8
114.9
85.9
92.4
Global warming (kg CO2 eq./F.U.)
Virgin PET R-PET PLA one-way PLA one-way
one-way
one-way
compost.
incin.
24.8
23.8
27.4
25.0
24.3
23.3
26.9
24.5
-2.1
54.5
119.5
-2.1
53.4
124.6
-1.9
57.0
-2.0
54.7
108.2
118.4
As it can be deduced, the more efficient case in which 60 items are contemporarily
transported does not imply any meaningful environmental advantage with respect to the base
case scenario, but the savings are limited to about 1-2% for all the impact indicators. This
because the allocation factor (1.67%) actually remains of the same order of magnitude of the
value employed in the base case (3.33%). No changes therefore take place in the comparison
among the investigated scenarios.
On the contrary, by assigning the full burdens to the consumer trip, the impacts of one-way
scenarios drastically increases also above 100%, abundantly worsening the respective
performances.
The total purchasing of 30 items appears therefore already an efficient option, as also the
modest contribution associated with this life cycle stage in the base case inventory
demonstrated (paragraph 5.2).
We have finally recognized through a more in depth analysis that also with an allocation
factor of 5% (total purchase of 20 items) the impacts increase by about 2% only ,while the
limit value for which the increase exceeds 10% begins at about 10% (total purchase of 10
items). Note that this corresponds to increasing the distance to 30 km when the allocation
factor is maintained at 3.33%. In order to better clarify the trend of variability of the impacts
342
as a function of the number of purchased items during the consumer trip, figure 5.22 shows
the example of the global warming indicator for the one-way virgin PET bottled water
scenario.
Global warming
kg CO2 eq./F.U.
60
50
54.5 (only water)
40
39.1 (2 items)
30
29.9
20
26.9
25.3
24.8
24.6
24.4
24.3
10
20
30
40
50
60
10
0
0
5
Number of purchased items
Figure 5.22: Variation of the global warming indicator with the number of purchased items for the one-way
virgin PET bottled water scenario
5.3.3 Washing frequency of reusable glass jug and allocation of dishwashing burdens
(tap groundwater scenario)
The washing frequency of the reusable glass jug utilised in the groundwater scenario as well
as the number of items contemporarily washed in the residential dishwasher define the
burdens associated with this life cycle stage of the reusable container. The base case of the
inventory arbitrarily assumed that the jug was washed after 4 uses as part of a load of 30
items, but since the dishwashing process is one of the major contributor to all the impact
indicators, we have considered meaningful to evaluate the effect of different washing policies,
in turn associated to different consumers behaviour. In particular, the following two cases are
examined:

more efficient washing conditions: washing of the jug after 5 uses as part of a load
of 50 items (allocation factor 1/50) and

more inefficient washing conditions: washing of the jug after each use as part of a
load of only 15 items (allocation factor 1/15).
The results obtained for the four considered indicators are represented in figures 5.23 and
E.17, as well as in tables 5.3 and E.8.
343
Cumulative energy demand (CED)
600
MJ eq./F.U.
587.8
400
468.6
546.8
481.7
439.7
365.8
307.8
200
177.4
50.0
0
w ay
PLA onew ay
compost.
PLA onew ay incin.
PET
GLASS PET ref illable
Tap
Tap surf ace
refillable
refillable
groundw ater w ater
40.5
Global warming
kg CO2 eq./F.U.
30
27.4
20
24.8
23.8
25.0
26.2
20.7
16.5
9.6
10
2.1
0
w ay
PLA onew ay
compost.
PLA onew ay incin.
GLASS
ref illable
PET ref illable
Tap
Tap surf ace
groundw ater w ater
1.5
Figure 5.23: Results of the sensitivity on dishwashing burdens on the CED and the global warming indicators in
the comparison among the investigated scenarios
Table 5.3: Results of the sensitivity on dishwashing burdens on the CED and the global warming indicators for
the tap groundwater scenario
CED
Global warming
(MJ eq./F.U.) (kg CO2 eq./F.U.)
Tap groundwater scenario
Base case
(washing every 4 uses/30 items)
MIN impact
(washing every 5 uses/50 items)
% min
MAX impact
(washing after each use/15 items)
% max
50.0
2.1
40.5
1.5
-18.9
177.4
254.9
-27.3
9.6
367.6
344
As it is possible to notice, when inefficient washing conditions are considered the impacts of
the scenario dramatically increase with respect to all the considered indicators, and especially
also up to 3.5 times for the global warming. However it always remains the best performing
one and therefore preferable from an environmental point of view, at least if the features of
the other systems are the same of those considered in the base case inventory. In the case of
more efficient washing conditions, the impacts decrease to a lower extent, but also up to about
30% for the global warming indicator, meaning that the washing policy considered in the base
case represents already a quite good choice. The performances of the scenario with respect to
those of base-case bottled water systems can be however improved by running the dishwasher
only when it is fully loaded or by reducing the frequency of washing of the reusable container
(i.e. after 5 uses). An even better profile can be achieved for this scenario if the reusable
container is only manually rinsed after its use just in view of the fact that the process of
dishwashing is the second most important contributor to the overall impacts of the scenario
itself (except for global warming, for which it holds the first place).
5.3.4 Transport distance from public fountains to consumers house (tap surface water
scenario)
Since the average distance of public fountains in the municipality of Florence from its city
centre results 5.5 km, this value was assumed, at a first instance, to represent the distance to
be covered by a citizen for the roundtrip between its house and a public fountain. Moreover,
the number of 1 litre bottles transported during each trip was assumed to be 9, for reasons of
coherence with the volume considered to be transported in one-way scenarios. The value
assumed for the distance seems to be quite realistic if considering that the service provided by
public fountains is mainly oriented at the citizens of the municipality in which they are
placed. However, in reason of the important contribution given by this transportation stage to
all the impact indicators, which also made the performances of such a tap water system
comparable to those of refillable PET bottled water, we have decided to better investigate the
potential effects of varying the distance.
345
The cases examined are therefore:

transportation of 9 litres for a distance of 2 km and

transportation of 9 litres for a distance of 10 km (which aims at modelling the
potential case in which a citizen of a surrounding municipality travels to the public
fountains to withdraw water).
Note that the use of these parameters has the same effects of considering that about 25 litres
or 5 litres of water are respectively transported for the base-case distance of 5.5 km.
Moreover, as pointed out in paragraph 5.2, it is also probable that the consumer trip is carried
out for a further purpose besides water withdrawal, for example to go to or come back from
the working place. The use of a 50% allocation factor of the burdens associated with the
transportation of 1 litre of water was therefore also proposed to account for the double aim of
the trip. However, since the utilisation of such a factor would have the same effects of halving
the distance to be covered during the trip, this was not performed in the specific. Indeed, the
effects of the reduction of the distance from 5.5 to 2 km will already explored.
It is finally worth to remember that if the consumer trip was performed by walk or by bicycle,
the meaningful contribution given by the utilisation of a car to the impacts of the present
scenario would vanish.
E.18, as well as in tables 5.4 and E.9. Note that in the figures the dotted part of the bars
regarding the impacts of the tap surface water scenario represent the contribution associated
with the use of the car for water transportation for the base case.
346
600.9
600
MJ eq./F.U.
587.8
400
468.6
546.8
481.7
439.7
365.8
307.8
200
50.0
182.9
78.4
0
w ay
PLA onew ay
compost.
PLA onew ay incin.
Tap
Tap surf ace
refillable
groundw ater w ater
Global warming
kg CO2 eq./F.U.
40
34.5
30
20
24.8
27.4
23.8
25.0
20.7
26.2
16.5
10
2.1
0
w ay
PLA onew ay
compost.
PLA onew ay incin.
GLASS
ref illable
10.0
3.8
PET ref illable
Tap
Tap surf ace
groundw ater w ater
Figure 5.24: Results of the sensitivity on transport distance from public fountains to consumers houses on the
CED and the global warming indicators in the comparison among the investigated scenarios (the dotted area in
the tap surface water bar specifies the contribution given by water transportation by car)
Table 5.4: Results of the sensitivity on transport distance from public fountains to consumers houses on the CED
and the global warming indicators for the tap surface water scenario
CED
Global warming
Tap surface water scenario
365.8
20.7
Base case (5.5 km)
182.9
10.0
MIN impact (2 km)
-50.0
-51.9
% min
600.9
34.5
MAX impact (10 km)
64.3
66.7
% max
347
The results show how the reduction of the distance to be covered to only 2 km also involves a
reduction of all the impacts of the present scenario of about an average 50%, making them
more comparable to those pertaining to the groundwater system. The most important remark
is however that in this condition the surface water system outperforms all bottled water
systems with respect to all the indicators, provided that their features are the same of those
considered for the base case inventory, in which the refillable PET bottled water scenario was
characterized by a better environmental profile.
On the contrary, as expected, the increase of the distance up to 10 km drastically worsens the
environmental profile of the scenario that becomes the worst performing among all, except for
the eutrophication indicator which remains comparable to the PET one-way and refillable
bottled water systems. In particular the value of the indicators increases on average of about
65%.
From these outcomes it appears clear how, in a very limited range of distances, the
performances of the present scenario with respect to all the others can significantly change. In
particular through a more in depth analysis we have recognized that the limit value of the
roundtrip distance which allows all the impact indicators of the surface water system to
remain slightly below the values pertaining to the PET refillable one is of about 4 km (always
for the transportation of 9 litres of water). This would be the same as considering that a
roundtrip distance of 8 km is covered for two different purposes and therefore only 50% of
the burdens of the trip are assigned to the transported water. The limit distance can instead
raise up to 6.5 km (or to 13 km with a 50% allocation factor) to obtain the same result if the
system is compared to the use of 50% recycled one-way PET bottles, which is the best
performing one-way system.
However to achieve a reduction of all the impact indicators, for instance of at least 30% with
respect to those of the two mentioned systems, the roundtrip distance should not outweigh
about 2.5 km and 4.2 km respectively, or either a double value with a 50% allocation factor.
The final consideration that can be made is therefore that if a capillary distribution of public
fountains within the territory to be served is assured, and if their utilisation is allowed only to
the citizens of the interested municipality, so that the use of a car is limited to very short
roundtrip distances (i.e. lower than 2-2.5 km) or better it is completely avoided, the
performances of a system based on this criterium would very probably result better than those
of any bottled water system.
348
5.3.5 Typology of containers employed to conserve water (surface water scenario)
In the base case, water was assumed to be conserved within 9 glass bottles with the capacity
of 1 litre each, with a conservative life span of 1 year. Since the use of plastic bottles with a
shorter life span is considered a possible alternative for water conserving, this practice is
included as sensitivity scenario. In particular 6 PET bottles with a capacity of 1.5 litres and
with the same features as those utilised in one-way scenario are assumed to be employed for 5
times. Therefore, the mass of PET required to deliver 1 litre of water is equal to:
M PET 
6 bottles  32.55 g/bottles
 4.34 g/litre
6 bottles/trip  1.5 litres/bot tles  5 trip
In the same manner, it is possible to define the amount of HDPE caps (unit mass of 2.06 g)
required by the system which results equal to 0.275 grams per litre. Bottles are assumed to be
recycled at the end of their useful life, while caps are incinerated. The respective life cycle
processes are modelled with the same methodology employed in one-way bottled water
scenarios, to which we refer for further details.
349
600
MJ eq./F.U.
587.8
400
468.6
546.8
481.7
439.7
365.8
348.5
307.8
200
50.0
0
w ay
PLA onew ay
compost.
PLA onew ay incin.
Tap
Tap surf ace
refillable
groundw ater w ater
Global warming
kg CO2 eq./F.U.
30
27.4
20
24.8
23.8
25.0
26.2
20.7
19.9
16.5
10
2.1
0
w ay
PLA onew ay
compost.
PLA onew ay incin.
GLASS
ref illable
PET ref illable
Tap
Tap surf ace
groundw ater w ater
Figure 5.25: Results of the sensitivity on the typology of reusable containers utilised in the surface water
scenario on the CED and the global warming indicators in the comparison among the investigated scenarios
Table 5.5: Results of the sensitivity on the typology of reusable containers utilised in the surface water scenario
on the CED and the global warming indicators for tap surface water scenario
CED
Global warming
Base case
(use of glass bottles)
MIN impact
(use of PET bottles)
%min
365.8
20.7
348.5
19.9
-4.7
-3.8
350
As it can be seen, the use of plastic bottles, even if characterized by a shorter useful life,
involves slight environmental advantages with respect to the use of glass bottles, from the
reduction of about 4% for the global warming indicator to about 8% for the eutrophication
indicator. These slight advantages must however be interpreted also in view of the very short
life span of 1 year conservatively assumed for glass bottles. Moreover it must be noticed how,
if the better performance of employing PET bottles remains even when they are utilised for
only 4 transportation cycles, the impacts of the scenario drastically increases if they are used
only once (for instance of about +37% for the global warming indicator, which reaches the
value of 28.3 kg CO2 eq.).
A further recommendation that can be made with regard to this scenario (but also to the use of
tap water in general) is therefore to utilise as much times as possible the reusable containers
employed for water conserving and in the particular case of PET bottles, to assure that they
are employed for at least 4 utilisation cycles.
5.3.6 Transportation distance between bottling plant and retailers or local distributors
(bottled water scenarios)
In the original inventory the distance between bottling plant and retailers for one-way
scenarios, or local distributors for refillable scenarios, was assumed equal to the average one
separating the bottling plant of the major Italian producers from the city of Milan. In
particular an average distance of 300 km resulted, but since also much lower (38 km) or much
higher (823 km) values were found, we have decided to include the potential effects of
assuming such values in this sensitivity analysis, considering the two following cases:

transportation for 40 km and

transportation for 800 km.
351
875.0
767.3
MJ eq./F.U.
800
648.0
726.3
619.2
587.8
600
468.6
439.7
400
375.2
200
494.5
560.1
546.8
481.7
453.5
307.8
365.8
346.4
277.2
176.6
50.0
0
w ay
PLA onew ay
compost.
PLA onew ay incin.
Tap
Tap surf ace
refillable
groundw ater w ater
Global warming
49.1
kg CO2 eq./F.U.
50
40
30
35.3
24.8
34.2
23.8
20
19.4
37.8
27.4
22.0
18.4
35.5
25.0
31.2
26.2
16.5
19.6
10
20.7
14.3
8.9
2.1
0
w ay
PLA onew ay
compost.
PLA onew ay incin.
GLASS
ref illable
PET ref illable
Tap
Tap surf ace
groundw ater w ater
Figure 5.26: Results of the sensitivity on the transport distance from bottling plants to retailers or local
distributors on the CED and the global warming indicators in the comparison among the investigated scenarios
352
Table 5.6: Results of the sensitivity on the transport distance from bottling plants to retailers or local
distributors on the CED and the global warming indicators for the interested scenarios
CED (MJ eq./F.U.)
Virgin
PLA
PLA
PET
R-PET one-way one-way GLASS
PET
one-way one-way compost. incin. refillable refillable
Base case
(300 km)
Min impact
(40 km)
%min
Max impact
(800 km)
%max
Base case
(300 km)
Min impact
(40 km)
%min
Max impact
(800 km)
%max
468.6
439.7
587.8
546.8
481.7
307.8
375.2
346.4
494.5
453.5
277.2
176.6
-19.9
648.0
-21.2
619.2
-15.9
767.3
-17.1
726.3
-42.5
875.0
-42.6
560.1
38.3
40.8
30.5
32.8
81.6
82.0
Virgin
PLA
PLA
PET
PET
one-way one-way compost. incin. refillable refillable
24.8
23.8
27.4
25.0
26.2
16.5
19.4
18.4
22.0
19.6
14.3
8.9
-21.9
35.3
42.1
-22.8
34.2
43.9
-19.8
37.8
38.1
-21.7
35.5
41.7
-45.4
49.1
87.3
-46.2
31.2
88.9
The first important remark is that with the meaningful decrease of the distance to be covered
from 300 km to 40 km, all bottled water scenarios result characterized by better performances
and in particular, as expected, the utilisation of refillable glass bottled water becomes
advantageous compared to one-way systems with respect to all the impact indicators except
for the eutrophication for which the systems are characterized by comparable values. Indeed,
as it can be seen in tables 5.6 and E.11, while one-way systems are characterized by an
average 20% reduction of the impacts (40% for eutrophication) with respect to the base case,
refillable systems register instead average reductions in the range of 40-45% (55% for
eutrophication). This because, according to the higher mass that has to be transported in
refillable scenarios (and in particular when glass bottles are utilised), with respect to one-way
scenarios, transportation burdens of the former respond with higher variations.
The PET refillable scenario remains however the best performing among all bottled water
scenarios and it is also better than the surface water scenario if the utilisation of a car with the
base case criteria of the inventory is foreseen. However, the sole reduction of transport
distance for one-way systems does not affect the better performances of the tap groundwater
system.
353
On the contrary, when transport distance increases up to 800 km the performances of all
bottled water scenarios drastically worsen and in particular those associated with refilling
systems, for the reasons early pointed out. In particular their impacts register an increase of
about 80-90% (106-108% for eutrophication), while for one-way systems of about 38-42%
(75-80% for eutrophication). In these conditions the use of refillable PET bottles results
always the preferable system except for the eutrophication indicator, for which it is
characterized by slightly worse performances than those of virgin and recycled PET one-way
systems. The refillable glass bottled water scenario finally results the worst performing one,
for the reasons explicated above.
5.3.7 Number of uses of refillable bottles (refillable scenarios)
Based on the information provided by the examined bottling plant and by another producer, a
number of 10 uses was hypothesised for refillable glass bottles in the inventory of chapter 4.
Refillable PET bottles were instead assumed to be used 15 times on the basis of literature data
reported by different studies concerning the German context.
In view of the intrinsic properties of glass, a number of 10 uses appears quite limited. Indeed
the mentioned studies consider an higher number of uses for this typology of bottles and,
since the values they report are considered very reliable according to the well established
nature of returning and refilling systems in Germany, on their basis we have defined the
values of the parameters to be used in the present sensitivity analysis.
A first important source is the already mentioned comprehensive LCA study published by the
German Federal Environmental Agency (UBA – Umweltbundesamt) which compares 27
packaging systems used for the delivering of mineral water, carbonated soft drinks, juices and
wines (UBA, 2000a; 2000b). In this study a number of uses for 0.75, 0.7 and 0.25 litres water
refillable glass bottles equal to 40, 50 and 29 are respectively considered. Being these values
the results of a thorough market research which refers to the period 1994-1995, it means that
they were actually achieved and potentially still now achievable.
The also already mentioned more recent LCA study (IFEU, 2008) conducted by the Institute
for Energy and Environmental Research (IFEU-Institut für Energie und Umweltforschung),
which compares mineral water one-way PET bottles with refillable glass and PET bottles
belonging to the pool of the Cooperative of German Mineral Wells (GDB: Genossenschaft
354
Deutscher Brunnen), considers a number of 40 uses for 0.7 litres refillable glass bottles not far
from that employed in the UBA study (UBA, 2000a; 2000b).
In the last study that was considered in paragraph 4.11.1, always performed by IFEU on
behalf of the German Industrial Association of Plastic Packaging (Industrievereinigung
Kunststoffverpackungen), which compares several packaging systems for mineral water and
carbonated soft drinks delivering (IFEU, 2010), 0.5 litres mineral water refillable glass bottles
are used 21 times while 0.7 litres and 0.75 litres ones 40 times.
Finally, the same GDB declares that refillable glass bottles belonging to its pool are used for
about 50 times, while those made of PET are used for about 15-25 times (GDB, 2010). The
various literature values are summarised for clarity in table 5.7.
Table 5.7: Number of refillable bottles uses considered in various sources
Number of refillable bottles uses
Typology of bottle
Source
UBA (2000a, 2000b)
IFEU (2008)
IFEU (2010)
Glass – 0.75 litres
40
-
40
Glass – 0.7 litres
50
40
40
Glass – 0.25 litres/0.5 litres
29 (0.25 l)
-
21 (0.5 l)
PET – generic
-*
-*
-*
GDB (2010)
50
(generic)
15-25
(*)The values considered by these sources were already reported in table 4.55.
On the basis of all these information, and excluding the values associated with little size
bottles (0.25-0.5 litres), characterized by a lower number of uses because they are generally
associated to an immediate (not domestic) consumption, we have decided to assume the
following sensitivity parameters:

50 uses for glass bottles, and

25 uses for PET bottles.
Note that the lower number of uses achievable with PET bottles is very likely associated with
its progressive degradation resulting from both their repeated use and, above all, from their
washing in warm caustic baths which fosters the potential hydrolysis of the polymeric chain,
diminishing the molecular weight of the material and, in last instance, its strength (paragraph
4.6).
355
600
MJ eq./F.U.
587.8
400
468.6
546.8
439.7
481.7
429.5
307.8
365.8
292.2
200
50.0
0
w ay
PLA onew ay
compost.
PLA onew ay incin.
Tap
Tap surf ace
refillable
groundw ater w ater
Global warming
kg CO2 eq./F.U.
30
26.2
27.4
20
24.8
23.8
25.0
25.2
16.5
20.7
15.8
10
2.1
0
w ay
PLA onew ay
compost.
PLA onew ay incin.
GLASS
ref illable
PET ref illable
Tap
Tap surf ace
groundw ater w ater
Figure 5.27: Results of the sensitivity on the number of uses of refillable bottles on the CED and the global
warming indicators in the comparison among the investigated scenarios
356
Table 5.8: Results of the sensitivity on the number of uses of refillable bottles on the CED and the global
warming indicators for refillable bottled water scenarios
CED
(MJ eq./F.U.)
GLASS refillable PET refillable
Base case
(10 glass/15 PET)
MIN impact
(50 glass/25 PET)
%min
Global warming
(kg CO2 eq./F.U.)
481.7
307.8
26.2
16.5
429.5
292.2
25.5
15.8
-10.8
-5.1
-2.6
-4.4
Surprisingly, the effects of increasing the number of uses assigned to refillable bottles appear
only marginal, especially with regard to PET bottles, for which a reduction of the impacts of
only between 2.6% and 5.1% is obtained. Slightly higher are the reductions registered for
glass bottles, about 11% for the CED indicator and 10% for the abiotic depletion.
The number of 15 uses of PET bottles seems therefore already a good target, especially in
view of the tendency of this material to the progressive degradation. On the contrary, the
recommendation to increase at least to 20-25 the number of glass bottles uses can be given,
even if an average increase of energy and resources savings of only about 5% is expected.
Glass is indeed not subject to degradation, being an inert material.
Transportation distances appear therefore the most important parameter with regard to
refillable scenarios, rather than the number of uses considered for bottles.
5.3.8 Upper and lower bounds
The values of the sensitivity parameters singularly considered in the previous paragraphs of
this section are finally combined in such a way to define the upper and the lower bound of the
potential impacts of each system with respect to all considered indicators. Table 5.9
summarises the way in which parameters are combined, while the results are represented in
figures 5.28 and E.22, as well as in tables 5.10 and E.13.
357
Table 5.9: Combination of sensitivity parameters for the definition of the upper and the lower bound of the
impacts associated with all the investigated systems
Tap water scenarios
Bottled water scenarios
Parameters/assumptions
Scenarios
Allocation factor of consumer
purchasing trip burdens
One-way bottled
water scenarios
Distance from bottling plants to
retailers/local distributors
All bottled
water scenarios
Number of uses for refillable
bottles
Refillable
bottled water
scenario
Allocation of dishwashing
burdens to the reusable glass jug
Tap
groundwater
scenario
Roundtrip distance from public
fountains to consumers houses
Typology of reusable containers
employed to conserve water
Tap surface
water scenario
Tap surface
water scenario
Lower
bound
Total
purchasing
of 60 items
(1.67%)
Base case
Upper bound
Total
purchasing of
30 items
(3.33%)
Purchasing of
only water
(100%)
40 km
300 km
800 km
Glass bottles:
50
PET bottles:
25
Washing
every 5 uses
as part of a
load of 50
items
Glass bottles:
10
PET bottles:
15
Washing
every 4 uses
as part of a
load of 30
items
2 km
5.5 km
10 km
6 PET bottles
by 1.5 litres
9 glass bottles
by 1 litre
-
-
Washing after
each use as
part of a load
of 15 items
358
1272.4
1200
1153.1
1231.3
1124.3
MJ eq./F.U.
1000
875.0
800
587.8
600
468.6
200
485.8
366.5
481.7
439.7
400
600.9
560.1
546.8
307.8
444.8
365.8
177.4
337.7
225.1
0
w ay
PLA onew ay
compost.
PLA onew ay incin.
161.0
50.0
165.6
GLASS PET refillable
Tap
Tap surface
ref illable
groundw ater w ater
40.5
Global warming
70
64.9
63.9
67.5
65.1
kg CO2 eq./F.U.
60
49.1
50
34.5
40
30
24.8
23.8
25.0
26.2
31.2
16.5
20
10
27.4
18.9
21.5
17.9
19.1
13.6
0
w ay
PLA onew ay
compost.
PLA onew ay incin.
GLASS
ref illable
8.2
20.7
9.6
2.1
9.2
PET ref illable
Tap
Tap surf ace
groundw ater w ater
1.5
Figure 5.28: Comparison among all the investigated scenarios of the upper and the lower bound obtained for
the CED and the global warming indicators on the basis of the variation of the parameters considered during
the sensitivity analysis
359
Table 5.10: Comparison among all the investigated scenarios of the upper and the lower bound obtained for the
CED and the global warming indicators on the basis of the variation of the parameters considered during the
sensitivity analysis
CED (MJ eq./F.U.)
Virgin
PLA
PLA
Tap
R-PET
GLASS
PET
Tap
PET
one-way one-way
surface
one-way
refillable refillable groundwater
one-way
compost. incin.
water
Base
case
Lower
bound
%min
Upper
bound
%max
Base
case
Lower
bound
%min
Upper
bound
%max
468.6
439.7
587.8
546.8
481.7
307.8
50.0
365.8
366.5
337.7
485.8
444.8
225.1
161.0
40.5
165.6
-21.8
1153.1
146.1
-23.2
1124.3
-17.4
1272.4
-18.7
1231.3
-53.3
875.0
-47.7
560.1
-18.9
177.4
-54.7
600.9
155.7
116.5
125.2
81.6
82.0
254.9
64.3
Virgin
PLA
PLA
Tap
PET
PET
Tap
surface
one-way one-way compost. incin. refillable refillable groundwater water
24.8
23.8
27.4
25.0
26.2
16.5
2.1
20.7
18.9
17.9
21.5
19.1
13.6
8.2
1.5
9.2
-24.0
64.9
161.6
-25.0
63.9
168.5
-21.7
67.5
146.3
-23.7
65.1
160.2
-48.0
49.1
87.3
-50.6
31.2
88.9
-27.3
9.6
367.6
-55.7
34.5
66.7
The results show a wide variability of the impacts, especially with regard to the upper bound
of bottled water systems, in particular because of the important contribution given by the
increase of transport distances and the allocation of consumers trip burdens. However we here
limit ourselves to provide some considerations concerning those aspects which could not
emerge when analysing the variation of the single parameters.
The first consideration is that the tap groundwater system maintains always its better
performances with respect to all of the one-way systems, even when the reusable jug is
washed in inefficient conditions (washing after each use as part of a load of only 15 items), a
short transport distance separates bottling plants from retailers (40 km) and an efficient
purchasing trip of consumers to retailers store is assumed (total purchasing of 60 items). As
already pointed out, the sole reduction of distances characterizing one-way systems along
with performing an efficient purchasing trip is not sufficient to affect the better performances
even of the worst case of the tap groundwater system, which does not involve the use of
packaging materials.
360
The tap groundwater system remains also better performing than the refillable glass bottled
one, when the latter is characterized by a short transport distance from bottling plant to
retailers, and bottles are used for 50 times.
When inefficient washing conditions of the reusable jug are considered, the performances of
the groundwater scenario are instead slightly worse than those of the refillable PET one, when
a short distance separates bottling plant from retailers (40 km) and bottles are used for 25
times. The only exception is represented by the eutrophication indicator, in respect of which
the last mentioned scenario is always slightly better performing. Finally, always in the case of
inefficient washing conditions, the groundwater system has an environmental profile
comparable to the best case surface water scenario.
With regard to the tap surface water systems, it is possible to notice how the best case in
which a roundtrip distance of only 2 km is considered to separate public fountains from
citizen house and plastic bottles are assumed to be utilised for 5 times, actually outperforms
all one-way bottled water systems, as well as the glass refillable one. On the contrary, it is
characterized by performances comparable to those of the best case PET refillable system
with respect to the CED and the global warming indicators, while it is always slightly better
with regard to the abiotic depletion and the eutrophication indicators.
As already emerged, the worst case of the surface water scenario, which is associated with a
roundtrip transportation distance fountains-citizen house of 10 km without any allocation
factor, is worse performing than all of the base cases of bottled water systems and also of the
worst case of the refillable PET bottled one, except for the eutrophication indicator in respect
of which it actually results better. It is also better performing than all the worst cases of oneway bottled water systems, as well as of the glass refillable one, but this does not however
justify the 10 km travelling distance to withdraw water from public fountains. The value of
the impacts to which it is compared (those of the worst cases of bottled water systems) has
indeed not to be taken as reference, being associated with very poor performances, even
greater of one order of magnitude with respect to the base case (especially for the CED
indicator).
With regard to the refillable PET system, it is possible to notice how its best case
(transportation for 40 km and use of bottles for 25 times) is always better performing than all
of the best cases of one-way systems (transportation for 40 km and efficient purchasing trip),
as well as of the best cases of the glass refillable one. Also its base case outperforms all the
361
best cases of one-way systems (the only exception being the eutrophication indicator), but not
the best case of the glass refillable one.
On the contrary, the advantages which characterize the PET refillable system vanish if this is
based on long distances (800 km) and one-way systems are based on medium (300 km) or
short distances (40 km).
Also the use of refillable glass bottles is advantageous from an environmental point of view
with respect to all one-way bottled water systems, if this is characterized by short distances
(40 km) even when the best cases of one-way systems are considered (the only exception
being the eutrophication indicator, for which they are characterized by comparable
performances).
It is finally important to notice how the worst cases of both refilling systems (long transport
distances) always constitute preferable options with respect to all one-way systems in the
extreme case in which they are characterized by long distances and inefficient purchasing trip.
From these results, it emerges therefore the importance of establishing a refilling system
characterized by short transport distances (for instance of the order of about 50 km) and, to a
lower extent, of assuring that glass bottles are utilised at least 20-25 times and PET bottles at
least 15 times. This in order to limit the magnitude of its potential impacts and to be actually
advantageous with respect to the use of one-way bottled water.
5.4 Concluding remarks and recommendations
The results obtained from the overall analysis confirm our initial consideration concerning
how a life cycle perspective has to be employed to verify if a waste prevention activity is
actually sustainable from an environmental point of view, by applying a systemic approach
which allows to evaluate all the associated energetic and environmental implications other
than the sole reduction of the generated waste.
Indeed, even if the tap groundwater system practically resulted the best performing for all the
examined conditions, a complex framework is instead emerged for the others investigated
scenarios. In particular, local aspects and consumers behaviour with regard to the use of tap
water, as well as transport distances for bottled water systems, are result very important
factors in the definition of the environmental performances of the respective scenarios, and
therefore on the results of their comparison with the other investigated systems.
362
By keeping in mind all these considerations, it is however possible to give some important
indications concerning the way of limiting not only waste generation but in general the
environmental impacts associated with drinking water consumption by citizens.
First of all, a reduction of the massive per capita consumption of one-way bottled (mineral)
water currently registered in Italy (paragraph 1.5), is suggested. In our opinion this should be
limited only to those cases in which, for instance for therapeutic reasons, the utilisation of
water with a given content of minerals is recommended.
A valid, less waste generating and less impacting alternative to the use of bottled water is
represented by the use of public network water. With regard to this statement, we remember
that drinkability of public network water at the point of use is a law requirement (paragraph
1.5).
Utilisation of public network water is suggested also when a domestic purification treatment
is carried out to improve the organoleptic quality of water, potentially worsened by the use of
chlorine based disinfectants, or to remove solid particles which could have contaminated the
water during its permanence into the distribution network because of its poor level of
maintenance (infiltration of soil particles or detaching of calcareous deposits).
According to the results of the analysis, the use of public network water further purified at
domestic level actually represents the best available option whatever are the features
potentially characterizing bottled water systems, provided that, if a dishwasher is used for the
washing of the reusable container employed to conserve water, this is operated according to
efficient criteria. Anyway, the systems results characterized by impacts corresponding to 255% of those associated with the use of one-way virgin PET or 50% recycled PET bottled
water. To achieve their minimization we then suggest either to assure a long useful life to the
reusable container or, when possible, to proceed only to its manual rinsing after use. If the use
of a dishwasher is instead foreseen, the respective impacts can be significantly reduced by
running it only when fully loaded, as well as by reducing the frequency of washing of the
container at least after 4 or 5 uses.
An equally valid option for the use of tap water resulted its delivering from public fountains
after its further quality improvement beyond traditional purifying treatments, provided that
certain conditions are assured. This also in order to limit the diffusion of the use of many
decentralized domestic purification systems which, if not adequately managed, can lead to
363
technical problems such as bacterial growing on activated carbon filters along with membrane
perforation, conditions in which water quality could be actually worsened (paragraph 1.5).
However, we have recognized how the means of transportation or either the distance to be
covered are the most important factors in discriminating the actual sustainability of the use of
such a system with respect to bottled water. In particular, if a car is utilised for water
transportation from public fountains to consumers houses, a roundtrip distance of about 2.5
km should not be exceeded to maintain the environmental performances of the system of at
least 6.5% below of the impacts of the best performing one-way bottled water system
(characterized by short distances and efficient purchasing trips to retailers). The distance
should instead decrease to 2 km to maintain its performances comparable to the best option of
a refilling system based on the use of PET bottles and short distances
Therefore, if a system based on the use of public fountains is to be implemented, care must be
taken in assuring that the average distance to be covered by a citizen does not exceed 2-2.5
km so that the use of a car can be limited. This can be achieved for instance by ensuring a
capillary distribution of fountains on the territory of the municipality to be served and by
limiting their utilisation to the respective citizens. A more beneficial behaviour would be to
completely avoid the use of a car, but we recognize that obviously this option cannot be
practiced by all the people and especially by the elder. However in this case the impacts of the
system would result in the range 6-21% of those pertaining to the use of virgin PET or 50%
recycled PET one-way bottled water.
The use of a refilling system based on PET bottles resulted another environmentally valid
alternative for the substitution of the use of one-way bottled water (whatever are the features
of the respective system), provided that it is characterized by short distances separating
bottling facilities from local distributors. In particular our recommendation for these lasts is to
choose, if possible, their supplier of bottled water in such a way that they are not separated
from a distance exceeding 50 (or at most 100) km. A further recommendation is also to assure
that bottles are used at least 15 times.
At the above mentioned interval of distances, but especially at 50 km, the use of refillable
glass bottles is still (longer) preferable to one-way bottled water but not with respect to
refillable PET bottles. Therefore, if a new refilling system is to be implemented in a certain
area, our suggestion is that PET should be utilised instead of glass bottles, keeping in mind all
the previous considerations concerning transport distances and number of bottles uses.
364
However, if maximum distances of 50-100 km are not exceeded also the use of refillable glass
bottles is suggested with respect to one-way ones.
Being our study not aimed at discriminating any typology of packaging system, but rather at
addressing consumers towards an environmentally sustainable behaviour at the moment of the
choice of a water supply option, we finally would like to provide some indications to improve
the environmental performances of one-way bottled water systems, for all that cases in which
their utilisation is not avoidable, for instance for therapeutic reasons, as discussed above.
First of all, the use of recycled raw materials for bottles manufacturing is an initial
appreciable effort for this purpose, but we have recognized that it only leads to marginal
environmental savings. More meaningful are instead those achievable by reducing transport
distances from bottling facilities to local retailers to about 50 km and if an efficient
purchasing trip to retailers is performed by citizens when a car is utilised, for example by
purchasing at least 30 items.
A last important finding of the study is that utilising polylactic acid as raw material for bottles
manufacturing does not appear a sustainable choice if composting or incineration are foreseen
as end of life options. Therefore a possible shifting to a large scale production of water
packaged in PLA bottles seems not justified in these conditions. Recycling of bottles could
lead to different conclusion but we believe that hardly it would affect the primacy of the use
of tap water or of a short distance based refilling system.
With regard to this issue, we finally underline how the potential impacts characterizing a tap
water system could be even lower than those resulted in this study, because we have
deliberately chosen to investigate two cases in which water is subject to quite intense
treatments, especially with regard to the use of surface water withdrawn from the Arno river.
On the contrary, there are other cases in which water is expected to undergo very limited
treatment stages such as the sole disinfection, before being introduced into the distribution
network. These would be for example the cases of mountains or hills spring water or of
groundwater withdrawn from aquifers of regions not interested by important industrial or
agricultural activities.
Limitations and future research
Some suggestions for the possible improvement of the life cycle modelling of the systems
investigated in the present study are here presented, as well as some indications for future
research.
First of all, modelling of PLA composting was carried out on the basis of several assumptions
with regard to its behaviour during this process, mainly based on the stoichiometry of the
degradation reaction in which it is involved, because of the unavailability of more precise
information. Therefore, despite composting does not result a proper end of life option for PLA
bottles, the life cycle modelling of this process could be improved by acquiring more precise
data concerning airborne emissions and generation of leachate.
More interesting would be to obtain data concerning the process of PLA recycling in order to
allow the modelling of a scenario in which this end of life option is taken into account. We
have however recognized that the level of development of such a process is only at an early
stage, and it appears unlikely that reliable life cycle data could be available within a short
period of time.
A last improvement concerning the modelling of the life cycle of PLA bottled water could be
made by obtaining more robust data on the potential energy savings achievable during
preforms and bottles manufacturing compared to PET ones, which in the present study were
defined on the basis of only rough estimates.
With regard to the life cycle of refillable PET bottles, primary data concerning energy
consumptions associated with the washing stage could be also obtained and utilised in
substitution of the estimates performed during the inventory.
Being water consumptions an always more important environmental issue, their quantification
in both the life cycles of tap and bottled water delivery could be finally more thoroughly
performed.
Only three environmental impact indicators were evaluated in the present study, because of
different reasons and in order to maintain the comparison among all the investigated scenarios
within reasonable limits.
366
Limitations and future research
In particular global warming was chosen being one of the most important contemporary
environmental issue, depletion of abiotic resources to provide a quantification of the savings
achievable through a waste prevention activity and finally eutrophication to evaluate if bottles
washing could represent a weak point of a refilling system. Energy utilisation in the life cycle
of the various investigated systems was finally traced through the cumulative energy demand
indicator.
A more in depth framework of the potential impacts associated with the different delivering
options could be however obtained by considering a wider number of impact indicators such
as, for instance, acidification, stratospheric ozone layer depletion, photochemical ozone
creation and a toxicity impact oriented indicator. In this case, despite the loosing of
transparency, the final comparison could be facilitated by the utilisation of a unique
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Starlinger, 2010b. viscotec, Solid State Polycondensation. viscoSTAR.
http://www.viscotec.at/assets/Uploads/Dokumente/viscoSTAR.pdf
Starlinger, 2010c. recoSTAR SSP. Accessed October 2010 from:
http://www.starlinger.com/en/recycling/solid-state-polycondensation/recostar-ssp/
Stockburger P., 1993. What you need to know before buying your next chlorine dioxide plant.
Tappi Journal 76 (3), 99-104.
http://tappi.micronexx.com/JOURNALS/PDFS/93MAR099.pdf
Temporelli G., Cassinelli N., 2005. L’acqua in tavola. Caratteristiche, produzioni, consumi,
controlli e legislazione vigente per le acque minerali naturali, le acque di sorgente, le acque
in boccione e quelle affinate al punto d’uso. FrancoAngeli, Milano.
Tenaris, 2007. General purpose, plumbing, gas and water pipes.
http://www.tenaris.com/shared/documents/files/CB35.pdf
TNO, 2010. Eco-profiles of the European Plastic Industry. Pet injection stretch blow
moulding. A report by TNO for PlasticsEurope.
UBA (German Federal Environmental Agency) (editor), 2000a. Life Cycle Assessment for
Drinks Packaging Systems II/Phase 1. UBA Texte 37/00. Umweltbundesamt, Berlin (in
German with English summary).
http://www.umweltdaten.de/publikationen/fpdf-l/1882.pdf
UBA (German Federal Environmental Agency) (editor), 2000b. Life Cycle Assessment for
Drinks Packaging Systems II/Phase 1. Collection of Materials UBA Texte 38/00.
Umweltbundesamt, Berlin (in German).
http://www.umweltdaten.de/publikationen/fpdf-l/1883.pdf
UNI, 2004. Prodotti chimici utilizzati per il trattamento di acque destinate al conusmo
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of water intended for human consumption: Polyaluminium chloride hydroxide ad
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Milano.
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Bibliography
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Viswas M. G., Aristippos G., Milford A. H., 2001. Laboratory composting of extruded
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come. Waste Management & Research 28 (3), 191-192.
Appendix A
Table A.1: Main Italian packaged mineral water producer groups and brands for the year 2008 (Bevitalia,
2009)
Rank Producer groups
S. Pellgrino
1
(Nestlè waters)
San Benedetto
(Zoppas)
2
3
4
5
6
7
8
Rocchetta/Uliveto
(CoGeDi)
Ferrarelle
(Pontecorvo)
Fonti di Vinadio
(Bertone)
Norda (Pessina)
Spumador
Monticchio
Brands
Acqua Panna-Levissima-Nestlè Vera-PejoRecoaro-San Bernardo-San Pellegrino
Acqua di Nepi-Fonte Vivia-Alpe Guizza Fonte
Caudana-Primavera delle Alpi-Gran Guizza Valle
Reale-Fonte Primavera-San Benedetto-Fonte
Guizza-Primavera Fonte Delicata
Rocchetta-Rocchetta Brio Blu-Uliveto
Boario-Vitasnella-Ferrarelle-Natia-Sant'Agata(Evian)
Alpi Bianche-Alte Vette-Sant’Anna di VinadioSant’Anna Sorgente Rebruant-Cime BiancheValle Stura
Daggio-Luna-Acquachiara-Ducale-Lynx-San
Fermo
Sant'Andrea-Sant'Antonio-San Carlo Spinone
Gaudianello-Leggera
First eight
Others producers
Total -Italy-
Volume produced - year 2008
Million litres
%
2.800
22.4
2.200
17.6
900
7.2
800
6.4
750
6
550
500
400
8.900
3.600
12.500
4.4
4
3.2
71.2
28.8
100
380
Appendix A
Table A.2: Calculated distance from Milan of bottling plants belonging to main Italian packaged mineral water
producer groups
Producer groups
S. Pellgrino
(Nestlè waters)
San Benedetto
(Zoppas)
Rocchetta/Uliveto
(CoGeDi)
Ferrarelle
(Pontecorvo)
Fonti di Vinadio
(Bertone)
Norda
(Pessina)
Spumador
Monticchio
Gaudianello
Sangemini
Brands
Acqua Panna
Levissima
Nestlè Vera (Fonte In Bosco)
Pejo
Recoaro
San Bernardo
San Pellegrino
Acqua di Nepi / Fonte Vivia
Alpe Guizza Fonte Caudana /
Primavera delle Alpi
Gran Guizza Valle Reale /
Fonte Primavera
San Benedetto / Fonte Guizza /
Primavera Fonte Delicata
Rocchetta / Rocchetta Brio Blu
Uliveto
Boario / Vitasnella
Ferrarelle / Natia / Sant'Agata/
(Evian)*
Alpi Bianche / Alte Vette /
Sant’Anna di Vinadio /
Sant’Anna Sorgente Rebruant /
Cime Bianche / Valle Stura
Daggio / Luna
Acquachiara
Ducale
Lynx / San Fermo
Sant'Andrea
Sant'Antonio
SanCarlo Spinone
Plant location
Scarperia (FI)
Cepina Valdisotto (SO)
San Giorgio in Bosco (PD)
Cogolo di Pejo (TN)
Recoaro Terme (VI)
Garessio (CN)
S. Pellegrino Terme (BG)
Nepi (VT)
Distance from
Milan
(km)
286
198
253
223
230
240
71
533
Donato (BI)
126
Popoli (PE)
618
Scorzè (VE)
Gualdo Tadino (PG)
Vico Pisano Terme (PI)
Darfo Boario Terme (BS)
272
491
300
131
Riardo (CE)
771
Vinadio (CN)
Primaluna (LC)
Valli del Pasubio (VI)
Tarsogno (PR)
Masanti di Bedonia (PR)
Medesano (PR)
Caslino al Piano (CO)
Spinone al Lago (BG)
249
79
262
189
184
139
38
80
Gaudianello / Leggera
Melfi (PZ)
823
Fabia / Effe Viva / Sangemini
(*) Not located in Italy and therefore non considered
San Gemini (TR)
Average distance
Assumed in this study
516
292
300
381
Appendix A
Table A.3: Masses of 1 litre glass bottles of main Italian mineral water brands (Provided by personal
communication with the companies)
Provided values
Assumed values
Brand
(g/bottle)
(g/bottle)
Acqua Panna
460
460
Levissima
475
475
Pejo
500
500
Recoaro
551.3
551.3
S. Bernardo
495-500
497.5
San Pellegrino
450-470
460
Rocchetta
450
450
Uliveto
450
450
Ferrarelle
450
450
Norda Daggio
450-470
460
Spumador S. Andrea 450 screw cap - 500 crown cap
475
Average
475
382
Appendix A
Appendix B
B.1 Airborne emissions of paper and PLA incineration processes
Table B.1: Airborne emissions calculated for paper and PLA incineration processes
Pollutants
Particulate
TOC*
CO
HCl
SOX
NOX
NH3
N2O
HF
PCDD/F
PAH
Sb
As
Cd+Tl
Cr
Co
Cu
Pb
Mn
Hg
Ni
Sn
V
Zn
Biogenic CO2
Concentrations Emission factors Emission factors
@ 11% O2, dry gas
PAPER
PLA
mg/m3n
mg/kgWW
0.09
0.65
0.84
0.4
2.91
3.72
5.8
42.21
53.93
1.9
13.83
17.67
0.4
2.91
3.72
39.6
288.2
368.2
0.71
5.17
6.60
0.96
6.99
8.93
0.13
0.95
1.21
ng/kgWW
0.0018
0.0131
0.0167
g/kgWW
0.052
0.378
0.484
0.5
3.64
4.65
1.1
3.64
4.65
0.5
8.01
10.23
0.5
3.64
4.65
0.5
3.64
4.65
2
3.64
4.65
0.6
4.37
5.58
0.5
4.37
5.58
0.6
14.55
18.60
0.5
3.64
4.65
0.5
3.64
4.65
0.65
4.73
6.04
mg/kgWW
0.0184
0.134
0.171
kg/kgWW
1.38
2.02
(*) Modelled as Non Methanic VOC in the LCA software
384
Appendix B
Appendix C
C.1 Composition and modelling of detergents employed for filler machine washing
Table C.1: Components of the alkaline detergent employed for daily filler machine washing and respective
modelling
Original components
Potassium hydroxide
Alkaline detergent (Enduro Super)
Composition
Ecoinvent module
(%)
Potassium hydroxide, at regional
15%
storage/RER
EDTA, ethylenediaminetetraacetic acid, at
5%
plant/RER
Alkylbenzene sulfonate, linear, petrochemical,
5%
at plant/RER
Tetrasodium EDTA
(ethylenediaminetetraacetic acid)
Anionic surfactant (potassium
alkylbenzenesulphonate)
Non-ionic surfactant (N,Ndimethyltetradecylamine N-oxide)
ethanol, 2,2´-iminobis-, N-tallow alkyldirivs.,
N-oxides
Demineralised water
5%
Dimethylamine, at plant/RER
(5%)
Not inventoried
70%
Water, deionised, at plant/CH
Table C.2: Components of the acid detergent employed for daily filler machine washing and respective
modelling
Original components
Phosphoric acid
Isoprophilic alchool
Non-ionic surfactant (N,Ndimethyltetradecylamine N-oxide)
Composition
Ecoinvent module
(%)
Phosphoric acid, industrial grade, 85% in
30%
H2O, at plant/RER
15%
Isopropanol, at plant/RER
Non-ionic surfactant (alkyl alcohol ethoxylate)
Cationic surfactant (cetrimonium chloride)
Demineralised water
5%
5%
(5%)
45%
Dimethylamine, at plant/RER
Ethoxylated alcohols, unspecified, at
plant/RER
Not inventoried
386
Appendix C
Table C.3: Components of the foaming disinfectant employed for daily filler machine washing and respective
modelling
Original components
Foaming disinfectant (Diverfoam active)
Composition
Ecoinvent module
(%)
10%
Acetic acid, 98% in H2O, at plant/RER
20%
Hydrogen peroxide, 50% in H2O, at plant/RER
Acetic acid
Hydrogen peroxide
Non-ionic surfactant (alkyl alcohol
ethoxylate)
Anionic surfactant (alkyl
benzenesulphonic acid)
Peracetic acid (PAA)
Modelled through its precursors:
 Acetic acid: 0.45 kg/kg PAA;
 Hydrogen peroxide: 0.79 kg/ kg PAA.
Demineralised water
5%
Ethoxylated alcohols, unspecified, at plant/RER
5%
Alkylbenzene sulfonate, linear, petrochemical, at
plant/RER
5%
 Acetic acid, 98% in H2O, at plant/RER;
 Hydrogen peroxide, 50% in H2O, at plant/RER.
55%
Table C.4: Components of the caustic detergent employed for weekly filler machine washing and respective
modelling
Original components
Sodium Hydroxide
Composition
Ecoinvent module
(%)
Sodium hydroxide, 50% in H2O, production mix,
30%
at plant/RER
Alkyl alcohol ethoxylate, modified (nonionic surfactant)
Alkyl alcohol alkoxylate (anionic surfactant)
Demineralised water
5%
(5%)
65%
Ethoxylated alcohols, unspecified, at plant/RER
Not inventoried
Table C.5: Components of the not-foaming disinfectant employed for weekly filler machine washing and
respective modelling
Not-foaming disinfectant (Divosan forte)*
Composition
Original components
Ecoinvent module
(%)
The disinfectant is a 15-30% peracetic acid
solution (PAA), modelled through its

Acetic acid, 98% in H2O, at plant/RER;
precursors:
30%

Hydrogen peroxide, 50% in H2O, at
 Acetic acid: 0.45 kg/kg PAA;
plant/RER.
 Hydrogen peroxide: 0.79 kg/ kg PAA.
Demineralised water
70%
(*) Also employed for bottles washing
387
Appendix C
C.2 Composition and modelling of detergents employed for bottles washing
Table C.6: Components of the descaling agent employed for bottles washing and respective modelling
Descaling agent (Divo MR)
Composition
Original components
(%)
Ecoinvent module
Sodium hydroxide, 50% in H2O, production mix, at
Sodium Hydroxide
2%
plant/RER
Tetrasodium ethylenediaminetetraacetate
EDTA, ethylenediaminetetraacetic acid, at
(EDTA)
30%
plant/RER
Demineralised water
68%
Table C.7: Components of the defoaming agent employed for bottles washing and respective modelling
Defoaming agent (Integra HD)
Original components
Composition (%)
Ecoinvent module
Alkyl alcohol alkoxylate
15%
Not inventoried
Nitrilotrimethylenetri(phosphonic acid)
5%
Not inventoried
Demineralised water
80%
Table C.8: Components of the sequestering agent employed for bottles washing and respective modelling
Components
Phosphonic acid
Nitrilotrimethylenetri(phosphonic
acid)
Demineralised water
Sequestering agent (Divo RL)
Composition
(%)
Ecoinvent module
Phosphoric acid, industrial grade, 85% in H2O, at
5%
plant/RER
(30%)
95%
Not inventoried
388
Appendix C
Appendix D
Virgin LDPE
granules
manufacturing
Virgin LLDPE
granules
manufacturing
Virgin LDPE
granules
manufacturing
Caps
injection
moulding
Labels
manufacturing
Heat shrink
films
extrusion
Stretch
films
extrusion
Top
films
extrusion
Cardboard
interlayer
production
Preforms
injection
moulding
Preforms stretch
blow moulding
Filling & packing
of bottles,
palletization of
bundles
Maintenance &
filler machine
washings
Hot rolled
steel for
nails
manufacturing
Pallets
manufacturing
Transport
packaging
materials
Primary
packaging
materials
Virgin PET
granules
manufacturing
Wooden
boards & glued
particle boards
manufacturing
Lubricating oil
manufacturing
Detergents
production
Lubricating oil
incineration
Unbleached
thermo-mechanical
pulp avoided
production
Cardboard
interlayer recycling
(manufacturing of
secondary pulp)
Transp. of
palletized bottles
Transp. of empty
pallets
Retailing
Wooden planks
avoided
production
Stretch films and
top films recycling
(manufacturing of
profiled bars made
from polyolefines)
Use and waste
generation
Pallets wood
recycling
(manufacturing of
particle boards)
Plywood boards
avoided
production
Pallets steel nails
recycling
(remelting in
EAF2)
Primary steel
avoided
production in
BOF1
Bottles, caps, labels and bundle heat shrink films to the
downstream processes of the waste management system
Appendix D
= Not modelled processes
= Fictitious processes
(1) BOF: Basic oxygen furnace
(2) EAF: Electric arc furnace
(3) WWTP: Wastewaters treatment plant
Transportation of
bottles bundle
Treatment of washing
water at WWTP3
390
Paper
production
Figure D.1: Representation of the major upstream life cycle processes characterizing baseline scenario 1
(utilisation of virgin PET one-way bottled water)
Virgin HDPE
granules
manufacturing
Virgin LDPE
granules
manufacturing
Virgin LLDPE
granules
manufacturing
Virgin LDPE
granules
manufacturing
Caps
injection
moulding
Labels
manufacturing
Heat shrink
films
extrusion
Stretch
films
extrusion
Top
films
extrusion
SSP4 of recovered
PET granules
Wooden
boards & glued
particle boards
manufacturing
Preforms
injection
moulding
Preforms stretch
blow moulding
Filling & packing
of bottles,
palletization of
bundles
Hot rolled
steel for
nails
manufacturing
Pallets
manufacturing
Transport
packaging
materials
Primary
packaging
materials
Virgin PET granules
manufacturing
Cardboard
interlayer
production
Lubricating oil
manufacturing
Maintenance &
filler machine
washings
Detergents
production
Lubricating oil
incineration
Unbleached
thermo-mechanical
pulp avoided
production
Cardboard
(manufacturing of
secondary pulp)
Transp. of
palletized bottles
Transp. of empty
pallets
Retailing
Wooden planks
avoided
production
Stretch films and
top films recycling
(manufacturing of
profiled bars made
from polyolefines)
Selection and
recycling of bottles
(for BtB2 recycling)
Use and waste
generation
Pallets wood
recycling
(manufacturing of
particle boards)
Plywood boards
avoided
production
Pallets steel nails
recycling
(remelting in
EAF3)
Primary steel
avoided
production in
BOF1
(1) BOF: Basic oxygen furnace (2) BtB: Bottle to Bottle (3) EAF: Electric arc furnace (4) SSP: Solid state polycondensation (5)WWTP: Wastewaters treatment plant
391
post consumer bottles
(only the amount
required for bottles
manufacturing)
Transportation of
bottles bundle
water at WWTP5
Appendix D
Paper
production
Figure D.2: Representation of the major upstream life cycle processes characterizing baseline scenario 2
(utilisation of recycled PET one-way bottled water) modelled through the closed loop approach; the processes
which differ from figure D.1 are represented in grey
Virgin HDPE
granules
manufacturing
Virgin LDPE
granules
manufacturing
Virgin LLDPE
granules
manufacturing
Virgin LDPE
granules
manufacturing
Caps
injection
moulding
Labels
manufacturing
Heat shrink
films
extrusion
Stretch
films
extrusion
Top
films
extrusion
Cardboard
interlayer
production
Preforms
injection
moulding
Preforms stretch
blow moulding
Filling & packing
of bottles,
palletization of
bundles
Maintenance &
filler machine
washings
Hot rolled
steel for
nails
manufacturing
Pallets
manufacturing
Transport
packaging
materials
Primary
packaging
materials
Virgin PLA
granules
manufacturing
Wooden
boards & glued
particle boards
manufacturing
Lubricating oil
manufacturing
Detergents
production
Lubricating oil
incineration
Unbleached
thermo-mechanical
pulp avoided
production
Cardboard
(manufacturing of
secondary pulp)
Transp. of
palletized bottles
Transp. of empty
pallets
Retailing
Wooden planks
avoided
production
Stretch films and
top films recycling
(manufacturing of
profiled bars made
from polyolefines)
Use and waste
generation
Pallets wood
recycling
(manufacturing of
particle boards)
Plywood boards
avoided
production
Pallets steel nails
recycling
(remelting in
EAF2)
Primary steel
avoided
production in
BOF1
Appendix D
Transportation of
bottles bundle
water at WWTP3
392
Paper
production
Figure D.3 Representation of the major upstream life cycle processes characterizing baseline scenario 3
(utilisation of PLA one-way bottled water), the processes which differ from figure D.1 are represented in grey
Virgin HDPE
granules
manufacturing
Activated carbon production
(for filter, as carbon coke)
2)Excavation and laying of pipes
Life cycle of GAC1 filters and
aeration towers materials manufacturing and recycling of
• stainless steel filters and towers
• carbon steel filters
• PP towers
Life cycle of pumping
stations
(pumps and buildings)
Activated
carbon
reactivation
Manufacturing of a
glass jug
Post consumer jug
Domestic ‘depuration’
(quality improvement)
Water purification
Activated
carbon
disposal in
landfill
Life cycle of water
reservoirs
(infrastructures)
Treatment of
rejected water
at WWTP2
Use at
consumers
house
Dishwashing
of the jug
water at WWTP2
Recycling of the
jug (only the
amount not
utilised for its
manufacturing)
(1) GAC: Granulated activated carbon (2) WWTP: Wastewaters treatment plant
Appendix D
Activated carbon
production
(modelled as
carbon coke)
393
Figure D.4: Representation of the major upstream life cycle processes characterizing waste prevention
scenario 1A (utilisation of purified groundwater from the tap)
Life cycle of water supply
network materials:
1)manufacturing and recycling of:
• carbon steel pipes
• cast iron pipes
• HDPE pipes
Sodium
hypochlorite
(NaClO)
production
Virgin PP
granules
manufacturing
PP pre-filter
extrusion
Activated
carbon
production
(for filter, as
carbon coke)
Manufacturing of
glass bottles
Mining and preparation of
quartziferous sand
Activated carbon production
(modelled as carbon coke)
Post consumer bottles
Withdrawing of
water from public
fountains
Public water quality
improvement
Water purification
Transportation
of withdrawn
water
Activated carbon reactivation
Disposal of sludge in landfill
Infrastructures: modelled as in the
tap groundwater scenario
(figure D.4)
PP pre-filter
incineration
Activated
carbon
disposal in
landfill
Treatment of
rejected water
at WWTP2
Avoided
energy
generation
(1) PWG: Potable water grade (2) WWTP: Wastewaters treatment plant
Recycling of bottles
(only the amount not
utilised for their
manufacturing)
Use at
consumers
house
394
Production of chemicals:
Hydrochloric acid (HCl)
Sodium chlorite (NaClO2)
Polyaluminium chloride (PACl)
Acrylonitrile (models PWG1
polyelectrolite)
Appendix D
scenario 1B (utilisation of purified surface water from public fountains)
•
•
•
•
•
Aluminium ingots
manufacturing
from virgin raw
materials and
industrial scraps
Hot and cold rolling of sheets
Caps moulding
aluminium caps
(only the amount
required for caps
manufacturing)
rejected bottles
(only the amount
required for bottles
manufacturing)
Paper
production
Virgin HDPE
granules
manufacturing
Virgin LDPE
granules
manufacturing
Labels
manufacturing
Crates
injection
moulding
Ligature
extrusion
Transport
packaging
materials
Primary
packaging
materials
NaOH &
detergents
production
Washing, filling &
packing of bottles,
palletization of
crates
Maintenance &
filler machine
washings
Detergents
production
Lubricating oil
incineration
water at WWTP3
Transp. of
palletized bottles
Ligature
incineration
Transp. of empty
palletized bottles
Local distributors
Transportation of
bottles crates
Transp. of crates
with empty bottles
Use
Pallets wood
recycling
(manufacturing of
particle boards)
Plywood boards
avoided
production
Pallets steel nails
recycling
(remelting in
EAF2)
Primary steel
avoided
production in
BOF1
Crates recycling
(production of
secondary HDPE
granules)
Virgin HDPE
granules avoided
production
395
Pallets
manufacturing
Waste generation
Remaining bottles, remaining caps and
labels to the downstream processes of the
waste management system
Avoided energy
generation
Hot rolled
steel for
nails
manufacturing
Lubricating oil
manufacturing
Depalletization of
crates & unpacking
of bottles from
crates
Wooden
boards & glued
particle boards
manufacturing
Appendix D
Aluminium ingots
manufacturing
from post
consumer scraps
scenario 2A (utilisation of refillable glass bottled water) modelled through the closed loop approach
Glass bottles
manufacturing (sorting
and remelting of cullet
with virgin raw
materials
Bottles injection stretch
blow moulding
Caps
injection moulding
Virgin PP granules
manufacturing
Virgin HDPE
granules
manufacturing
Virgin LDPE
granules
manufacturing
Crates
injection
moulding
Ligature
extrusion
Labels film extrusion
Labels
manufacturing
Primary
packaging
materials
NaOH &
detergents
production
Transport
packaging
materials
Hot rolled
steel for
nails
manufacturing
Pallets
manufacturing
Lubricating oil
manufacturing
Depalletization of
crates & unpacking
of bottles from
crates
Wooden
boards & glued
particle boards
manufacturing
Washing, filling &
packing of bottles,
palletization of
crates
Maintenance &
filler machine
washings
Detergents
production
Lubricating oil
incineration
Waste generation
Bottles, caps and labels to the downstream
processes of the waste management system
Avoided energy
generation
Ligature
incineration
water at WWTP3
Transp. of
palletized bottles
Local distributors
Transportation of
bottles crates
Transp. of crates
with empty bottles
Use
Pallets wood
recycling
(manufacturing of
particle boards)
Plywood boards
avoided
production
Pallets steel nails
recycling
(remelting in
EAF2)
Primary steel
avoided
production in
BOF1
Crates recycling
(production of
secondary HDPE
granules)
Virgin HDPE
granules avoided
production
Appendix D
Transp. of empty
palletized bottles
396
Virgin HDPE granules
manufacturing
scenario 2B (utilisation of refillable PET bottled water), the processes which differ from figure D.6 are
represented in grey
Virgin PET granules
manufacturing
Appendix D
397
Table D.1: Major upstream life cycle processes characterizing baseline scenario 1 (utilisation of virgin PET
one-way bottled water)
Processes/natural resources consumptions/emissions
Unit
Amount
PET preforms manufacturing*
Production of virgin bottle grade PET granules
g/l
22.6
Injection moulding of preforms from granules
HDPE caps manufacturing*
Production of virgin HDPE granules
g/l
1.62
Injection moulding of caps from granules
Paper labels manufacturing
Production of wood-containing mechanical paper
g/l
0.404
LDPE bundle heat shrink films manufacturing*
Production of virgin LDPE granules
g/l
2.55
Extrusion of films from granules
Handle PP adhesive tape manufacturing*
Production of virgin PP granules
g/l
0.055
Extrusion of tape from granules
Handle cardboard strip manufacturing
Production of cardboard (white lined chipboard)
g/l
0.146
Incineration of handle adhesive tape
g/l
0.054
Incineration of handle cardboard strip
g/l
0.146
Production of wooden standard 80×120 cm EUR-EPAL pallets (only materials)
unit/l
6.54×10-5
Cardboard interlayer manufacturing
Production of cardboard (white lined chipboard)
g/l
2.54
LLDPE stretch-films manufacturing*
Production of virgin LLDPE granules
g/l
0.329
LDPE top films manufacturing*
g/l
0.235
Recycling of pallets wood (manufacturing of particle boards)
kg/l
1.61×10-3
Recycling of pallets steel nails (remelting in electric arc furnace)
kg/l
1.28×10-5
Recycling of cardboard interlayer (manufacturing of secondary pulp)
g/l
2.54
Recycling of films (manufacturing of profiled bars made from polyolefines)
g/l
0.55
Electricity for bottling plant operations (including preforms stretch blow
kWh/l
0.0207
moulding)
Lubricating oil manufacturing (for machineries maintenance)
kg/l
1.56×10-6
Lubricating oil incineration
kg/l
1.56×10-6
(*) The transportation of granules for 100 km by lorry and 200 km by rail from the manufacturing to the
conversion plant is also considered
398
Appendix D
Filler machine washing
Water, unspecified origin (natural resource)
Alkaline detergent (daily washing)
Acid detergent (daily washing)
Foaming disinfectant (daily washing)
Caustic detergent (weekly washing)
Not-foaming disinfectant (weekly washing)
COD waterborne emissions
Nitrogen (N) waterborne emissions
Phosphorus (P) waterborne emissions
Treatment of washing water (unpolluted sewage) to wastewater treatment plant
Transportations
Transportation of palletized bundles from bottling plant to retailers (and return
trip with empty pallets) by lorry > 16 t (European fleet average) for 300 km
(single trip)
Roundtrip transportation of one bundle from retailers to consumers house for
10 km
litres/l
kg/l
kg/l
kg/l
kg/l
kg/l
g/l
g/l
g/l
litres/l
0.0388
3.75×10-6
2.5×10-6
1.88×10-6
1.88×10-6
6.55×10-6
1.01×10-3
1.63×10-5
2.21×10-4
0.0388
kg×km/l
318.9
(delivering
trip)
9.72
(return trip)
km/l
0.037
Table D.2: Major upstream life cycle processes characterizing baseline scenario 2 (utilisation of recycled PET
one-way bottled water, modelled through the closed loop approach) which differ from baseline scenario 1
Processes
Unit
Amount
PET preforms manufacturing*
g/l
11.3
Selection of post consumer PET bottles
g/l
14.1
Mechanical recycling of post consumer PET bottles (production of secondary
g/l
14.1
PET granules)
Solid state polycondensation (SSP) of recovered PET granules
g/l
11.3
g/l
22.6
(*) The transportation of granules for 100 km by lorry (>16 t) and 200 km by rail from the manufacturing to the
Table D.3: Major upstream life cycle processes characterizing baseline scenario 3 (utilisation of PLA one-way
bottled water) which differ from baseline scenario 1
Processes
Unit
Amount
PLA preforms manufacturing*
Production of virgin PLA granules
g/l
22.6
399
Appendix D
Table D.4: Major upstream life cycle processes characterizing waste prevention scenario 1A (utilisation of
purified groundwater from the tap)
Water purification
Groundwater (natural resource)
Electricity
Production of virgin activated carbon (modelled as carbon coke)
Reactivation of exhausted activated carbon
Production of sodium hypochlorite (NaClO – pure substance)
Water supply network materials life cycle
Manufacturing of carbon steel hot rolled sheets
Drawing of seamless pipes from hot rolled steel sheets
Manufacturing of cast iron ingots
Hot rolling of sheets from cast iron ingots
Drawing of seamless pipes from hot rolled cast iron sheets (approximation of
the real process)
Production of cement mortar for cast iron pipes coating (internal surface)
Production of zinc for cast iron pipes coating (external surface)
Manufacturing of virgin HDPE granules
Extrusion of pipes from HDPE granules
Recycling of steel and cast iron pipes (remelting in electric arc furnace)
Recycling of HDPE pipes (production of secondary HDPE granules)
Excavation with hydraulic digger for laying of pipes (from Ecoinvent)
Building machine life cycle (for laying of pipes, from Ecoinvent, as MJ of
consumed diesel)
GAC filters and aeration towers materials life cycle
Manufacturing of stainless steel hot rolled sheets
Manufacturing of carbon steel hot rolled sheets
Cold rolling of steel sheets for filters and towers manufacturing
Injection moulding of towers from granules (approximation of the real process)
Recycling of steel filters and towers (remelting in electric arc furnace)
Recycling of PP towers (production of secondary PP granules)
Pumping stations: life cycle of materials utilised for pumps and infrastructures
manufacturing (from Ecoinvent)
Water reservoirs: life cycle of materials utilised for reservoirs manufacturing
(from Ecoinvent)
Domestic depuration of water (quality improvement)
Purified groundwater from the tap (module described above in this table)
Electricity
Production of activated carbon for the filter (modelled as carbon coke)
Disposal of activated carbon into an inert material landfill
Treatment of rejected water (unpolluted sewage) at wastewaters treatment plant
Glass jug life cycle
Manufacturing of a generic white glass container (from 60.5% of glass cullet)
Recycling of the jug (remelting with virgin raw materials), only the amount not
employed for jug manufacturing
Unit
Amount
litres/l
kWh/l
kg/l
kg/l
kg/l
1.12
0.000485
6.12×10-7
1.22×10-5
1.03×10-7
kg/l
1.76×10-6
kg/l
1.19×10-5
kg/l
kg/l
2.99 ×10-7
8.20 ×10-8
kg/l
2.41×10-8
kg/l
kg/l
m3/l
1.37×10-5
2.4×10-8
1.37×10-6
MJ/l
7.37×10-6
kg/l
kg/l
kg/l
6.205×10-8
5.14×10-8
1.13×10-7
kg/l
2.81×10-10
kg/l
kg/l
1.13×10-7
2.79×10-10
units/l
1.99×10-12
units/l
5.32×10-12
litres/l
kWh/l
kg/l
kg/l
litres/l
3
2.63×10-3
3.3×10-3
3.3×10-3
2
g/l
3.12
g/l
1.23
400
Appendix D
Dishwashing of the jug
Electricity
Purified water from the tap
Treatment of washing water (unpolluted sewage) at wastewaters treatment plant
kWh/l
litres/l
litres/l
0.011
0.131
0.131
Table D.5: Major upstream life cycle processes characterizing waste prevention scenario 1B (utilisation of
purified surface water from public fountains)
Water purification
River water (natural resource)
Electricity
Production of hydrochloric acid (HCl) - pure substance
Production of sodium chlorite (NaClO2) - 25% m/m solution
Production of polyaluminium chloride (PACl) - 10% as Al2O3 m/m sol
Production of sodium hypochlorite (NaClO) - pure substance
Production of acrylonitrile (models PWG* polyelectrolyte)
Production of quartziferous sand
Production of virgin activated carbon (modelled as carbon coke)
Reactivation of exhausted activated carbon
Disposal of sludge into an inert material landfill
Water supply network materials life cycle (as groundwater scenario, table D.4)
GAC filters and aeration towers materials life cycle (as groundwater scenario,
table D.4)
Pumping stations: life cycle of materials utilised for pumps and infrastructures
manufacturing (from Ecoinvent, as groundwater scenario, table D.4)
Water reservoirs: life cycle of materials utilised for reservoirs manufacturing
(from Ecoinvent, as groundwater scenario, table D.4)
Public water quality improvement
Purified surface water from the network (module described above in this table)
Electricity
Production of virgin PP granules for pre-filter manufacturing
Extrusion of pre-filter from PP granules
Production of activated carbon for the filter (modelled as carbon coke)
Incineration of PP pre-filter
Disposal of activated carbon into an inert material landfill
Treatment of rejected water (unpolluted sewage) at wastewaters treatment plant
Glass bottles life cycle
Manufacturing of a generic green glass container (from 83.5% of glass cullet)
Manufacturing of a generic white glass container (from 60.5% of glass cullet)
Recycling of bottles (remelting with virgin raw materials), only the amount not
employed for bottles manufacturing
Water transportation
Roundrtip transportation of bottles from public fountains to consumers house by
car for 5.5 km
(*) PWG: Potable Water Grade
Unit
Amount
litres/l
kWh/l
kg/l
kg/l
kg/l
kg/l
kg/l
kg/l
kg/l
kg/l
kg/l
-
1.18
0.000382
6.33×10-6
1.68×10-5
7.2×10-5
1.46×10-6
3.22 ×10-7
1.18×10-5
1.29×10-6
1.08×10-5
1.74 ×10-5
-
-
-
units/l
1.99×10-12
units/l
5.32×10-12
litres/l
kWh/l
1.08
0.01
kg/l
1.54×10-5
kg/l
kg/l
kg/l
litres/l
4.17×10-5
1.5×10-5
4.17×10-5
0.08
g/l
g/l
14.05
14.05
g/l
7.87
km/l
0.611
Appendix D
401
Table D.6: Major upstream life cycle processes characterizing waste prevention scenario 2A (utilisation of
refillable glass bottled water), modelled through the closed loop approach
Unit
Amount
Bottles manufacturing
Manufacturing of white glass bottles (generic glass container from 60.5% of
g/l
23.75
cullet)
Manufacturing of green glass bottles (generic glass container from 80.5% of
g/l
23.75
cullet)
Aluminium caps manufacturing
Manufacturing of aluminium ingots (European mix)
Fabrication of aluminium sheets from ingots (hot and cold rolling)
g/l
1.75
Moulding of caps from sheets
(approximated with the process of cold impact extrusion)
Paper labels manufacturing
Production of wood-containing mechanical paper
g/l
1.06
HDPE crates manufacturing*
g/l
1.68
Injection moulding of crates from granules
Recycling of crates (production of secondary HDPE granules)
g/l
1.67
Production of wooden 95×120 cm pallets (only materials)
unit/l
9.26×10-5
LDPE ligature manufacturing*
g/l
0.04
Extrusion of ligature from granules
kg/l
2.70×10-3
kg/l
2.14×10-5
Ligature incineration
g/l
0.039
Electricity for bottling plant operations (including bottles washing)
kWh/l
0.0134
Lubricating oil manufacturing (for machineries maintenance)
kg/l
1.56×10-6
Lubricating oil incineration
kg/l
1.56×10-6
Filler machine washing
modelled as in one way scenarios
402
Appendix D
Bottles washing
Water, unspecified origin (natural resource)
Natural gas (burned in industrial furnace)
Caustic soda (NaOH), pure substance
Descaling agent
Defoaming agent
Sequestering agent
Not-foaming disinfectant
COD waterborne emissions
Nitrogen (N) waterborne emissions
Phosphorus (P) waterborne emissions
Treatment of washing water (unpolluted sewage) to wastewaters treatment plant
Transportations
litres/l
MJ/l
kg/l
kg/l
kg/l
kg/l
kg/l
g/l
g/l
g/l
litres/l
Transportation of palletized water from bottling plant to local distributors (and
return trip with empty palletized bottles) by lorry > 16 t (European fleet
average) for 300 km (single trip)
kg×km/l
Transportation of bottles crates from local distributors to consumers house (and
return trip with empty bottles) by lorry 3.5-16 t (European fleet average) for 20
km (single trip)
kg×km/l
1
0.223
7.98×10-4
2.5×10-4
2.19×10-4
9.38×10-5
5.31×10-5
1.63×10-1
6.01×10-3
1.37×10-3
1
510
(delivering trip)
210
(return trip)
32.8
(delivering trip)
12.8
(return trip)
Appendix D
403
Table D.7: Major upstream life cycle processes characterizing waste prevention scenario 2B (utilisation of
refillable PET bottled water)
Unit
Amount
PET bottles manufacturing*
g/l
4.13
Injection stretch blow moulding of bottles from granules
HDPE caps manufacturing*
g/l
3.22
Injection moulding of caps from granules
PP labels manufacturing*
g/l
0.615
Extrusion of labels film from granules
HDPE crates manufacturing*
g/l
1.55
Injection moulding of crates from granules
Recycling of crates (production of secondary HDPE granules)
g/l
1.54
Production of wooden 80×120 cm standard EUR-EPAL pallets (only materials)
unit/l
1.04×10-4
LDPE ligature manufacturing*
g/l
0.0384
Extrusion of ligature from granules
kg/l
2.56×10-3
kg/l
2.03×10-5
Ligature incineration
g/l
0.0375
modelled as in the glass refillable scenario (table D.6) except for natural gas consumptions of bottles washing:
Natural gas (burned in industrial furnace)
MJ/l
0.089
Transportations
381
Transportation of palletized water from bottling plant to local distributors (and
(delivering trip)
return trip with empty palletized bottles) by lorry > 16 t (European fleet
kg×km/l
81
average) for 300 km (single trip)
(return trip)
24.4
Transportation of bottles crates from local distributors to consumers house (and
(delivering trip)
return trip with empty bottles) by lorry 3.5-16 t (European fleet average) for 20
kg×km/l
4.4
km (single trip)
(return trip)
404
Appendix D
Appendix E
Global warming -closed loop
approach-
11.3
kg CO2 eq/F.U.
kg CO2 eq/F.U.
11.3
11
5
-1
Global warming -hybrid approach-
-0.49
10
5
0
Preform s production
Preform s production
Abiotic depletion -closed loop
approach-
Abiotic depletion -hybrid approach105.8
100
g Sb eq/F.U.
g Sb eq/F.U.
105.8
50
-15
50
0
-50
-55.2
-100
-10.3
Preforms production
Preforms production
Eutropication -closed loop
approach-
Eutropication -hybrid approach-
7.1
7.1
g PO43- eq/F.U.
g PO43- eq/F.U.
-3.0
-5
5
-1
-0.92
5
0
-5
-5.0
Preforms production
Preforms production
Figure E.1: Contribution of the processes of preforms manufacturing and bottles recycling to global warming,
abiotic depletion and eutrophication impact indicators for the recycled PET one way bottled water scenario
modelled through the two different approaches described in paragraph 4.6
406
Appendix E
g PO43- eq./F.U.
g Sb eq./F.U.
Abiotic depletion
2.2
2
1
0.54
0
0.8
Eutrophication
0.75
0.6
0.4
0.30
0.2
0.0
Figure E.2: Contribution of the PLA composting process to the abiotic depletion and eutrophicaiton impact
indicators for the PLA one way bottled water scenario
Eutrophication
Abiotic depletion
0.5
0.016
0.0
0.0016
-0.18
-0.25
-0.5
0.25
g PO43- eq./F.U.
1.0
g Sb eq./F.U.
0.29
0.95
0.15
0.05
0.042
0.020
0.013
-0.017
-0.05
-0.050
Direct emissions from composting
Leachate treatment
Peat avoided
Fertilizers avoided
Leachate treatment
Peat avoided
Fertilizers avoided
Figure E.3: Contribution by sub processes to the abiotic depletion and eutrophication impact indicators for PLA
composting modelled through the process specific approach
Eutrophication
Abiotic depletion
1.0
0.95
0.5
0.0027
0.0
g PO43- eq./F.U.
g Sb eq./F.U.
1.25
0.690
0.50
0.042
0.022
0.00
Leachate treatment
Leachate treatment
Figure E.4 Contribution by sub processes to the abiotic depletion and eutrophication impact indicators for PLA
composting modelled through the PLA specific approach
407
Appendix E
Eutrophication: contribution by subprocesses (TAP GW scenario)
14.6
15
10
7.7
5
2.6
0.989
0
g PO43- eq/F.U.
g Sb eq/F.U.
Abiotic depletion: contribution by subptocesses (TAP GW scenario)
0.40
0.36
0.33
0.30
0.21
0.20
0.10
0.042
0.00
Jug washing
Jug washing
Figure E.5: Contribution of the major sub-processes to the abiotic depletion and the eutrophication impact
indicators calculated for tap groundwater scenario
150
114.0
100
50
24.9
6.5
0
0.37
Eutrophication: contribution by subprocesses (TAP SW scenario)
g PO43- eq/F.U.
g Sb eq/F.U.
Abiotic depletion: contribution by subprocesses (TAP SW scenario)
10
5
8.0
2.0
0.3
0
0.017
indicators calculated for tap surface water scenario
408
Appendix E
g Sb eq/m 3
2.00
2
1
0.133
0.033
0.00070
0
Eutrophication: contributions to
g PO43-eq/m 3
Abiotic depletion: contributions to
0.10
0.085
0.05
0.0057 0.00088 3.76E-05
0.00
Infrastructures
Infrastructures
Hypochlorite prod.
Hypochlorite prod.
Figure E.7: Contributions of the major sub-processes to the abiotic depletion and the eutrophication impact
indicators calculated for the treatment and the delivering of 1 m3 of groundwater
409
Appendix E
Abiotic depletion: contributions to water treatment and
delivering
g Sb eq/m 3
1.5
1.6
1.0
0.48
0.5
0.13
0.048
0.0016
0.0015
0.0
Chemicals prod.
Infrastructures
Sand production
Sludge disposal
Eutrophication: contributions to water treatment and
delivering
g PO43- eq/m 3
0.067
0.05
0.028
0.0057
0.0012
0.00015 8.49E-05
0.00
Chemicals prod.
Infrastructures
Sludge disposal
Sand production
indicators calculated for the treatment and the delivering of 1 m3 of surface water
410
Appendix E
Abiotic depletion: contribution by sub-processes (Virgin PET one way
scenario)
162.9
g Sb eq/F.U.
140
90
46.0
40
14.6
13.0
6.9
11.5
5.3
-10
-8.5
-60
-55.2
Preforms production
Eutrophication: contribution by su-processes (Virgin PET one way
scenario)
g PO43- eq/F.U.
12.2
9
4
7.35
0.67
0.49
0.33
0.31
-1
0.18
-0.17
-6
-5.0
Preforms production
indicators calculated for virgin PET one way bottled water scenario
411
Appendix E
Abiotic depletion: contribution by sub-processes (PET refillable
scenario)
g Sb eq/F.U.
80
64.7
60
40
27.2
25.1
20
10.2
9.6
8.4
5.2
0
1.2
-20
-11.6
-13.2
Bottles production
Bottles washing
Recycling bottles
Eutrophication: contribution by sub-processes (PET refillable scenario)
12
10.3
g PO43- eq/F.U.
10
8
6
4
2
2.2
1.8
1.7
0.5
0.5
0.1
0.023
0
-0.16
-2
-1.2
Bottles production
Bottles washing
Recycling bottles
indicators calculated for PET refillable bottled water scenario
412
Appendix E
Abiotic depletion: contribution by sub-processes (GLASS refillable
scenario)
120
g Sb eq/F.U.
100
100.8
80
60
48.4
40
21.5
20
17.3
16.1
8.4
5.6
0
1.3
-6.3
-20
-11.5
Bottles production
Bottles washing
Recycling bottles
Eutrophication: contribution by sub-processes (GLASS refillable
scenario)
20
g PO43- eq/F.U.
16.1
15
10
5
4.0
2.7
1.9
1.3
0.48
0.16
0.024
0
-0.68
-5
Bottles production
Bottles washing
Recycling bottles
-0.84
indicators calculated for glass refillable bottled water scenario
413
Appendix E
Cumulative energy demand: contribution by sub-processes (R-PET one
way scenario)
255.6
MJ eq./F.U.
250
150
107.7
36.1
50
30.8
29.5
17.4
7.6
-20.5
-50
-24.5
Preforms production
Global warming: contribution by sub-processes (R-PET one way
scenario)
15
kg CO2 eq/F.U.
11.3
10
6.3
5
1.8
1.4
1.1
1.0
0.88
0.59
0
-0.49
-5
Preforms production
Figure E.12: Contribution of the major sub-processes to the CED and the global warming indicators calculated
for recycled PET bottled water scenario
414
Appendix E
Abiotic depletion: contribution by sub-processes (R-PET one way
scenario)
120
105.8
g Sb eq/F.U.
100
80
60
46.0
40
14.6
20
11.5
13.0
6.9
5.3
0
-20
-8.5
-10.3
Preforms production
Eutrophication: contribution by sub-processes (R-PET one way
scenario)
g PO43- eq/F.U.
8
7.4
7.1
6
4
2
0.67
0.49
0.33
0.31
0.18
0
-0.17
-2
-0.92
Preforms production
indicators calculated for recycled PET bottled water scenario
415
Appendix E
Abiotic depletion: contribution by sub-processes (PLA one way to
120
115.2
g Sb eq/F.U.
100
80
46.0
60
40
14.6
20
11.5
11.3
6.9
5.3
2.2
0
-0.14
-20
-3.4
Preforms production
Composting bottles
Eutrophication: contribution by sub-processes (PLA one way to
g PO43- eq/F.U.
30
27.1
25
20
15
10
5
0
7.4
0.75
0.60
0.49
0.33
0.31
0.18
-0.0021 -0.067
-5
Preforms production
Composting bottles
indicators calculated for PLA to composting bottled water scenario
416
Appendix E
Abiotic depletion: contribution by sub-processes (PLA one way to
g Sb eq/F.U.
150
115.2
100
46.0
50
14.6
11.5
11.3
6.9
5.3
-0.1
0
-3.4
-50
-16.9
Preforms production
Eutrophication: contribution by sub-processes (PLA one way to
g PO43- eq/F.U.
30
27.1
25
20
15
10
5
0
7.4
0.60
0.49
0.33
0.31
0.18
-0.0021 -0.067
-5
-0.45
Preforms production
indicators calculated for PLA to incineration bottled water scenario
417
Appendix E
Abiotic depletion
396.9
384.6
409.7
390.6
g Sb eq./F.U.
400
300
200
196.6
193.1
184.3
180.8
209.4
205.9
190.3
186.8
201.6
100
145.8
126.8
25.9
0
w ay
PLA onew ay
compost.
PLA onew ay incin.
Tap
Tap surf ace
refillable
groundw ater w ater
Eutrophication
51.1
49.9
g PO43- eq./F.U.
50
37.1
40
30.5
29.4
30
20
10
16.4
16.2
36.8
35.9
35.6
25.2
15.3
15.9
15.1
0.94
10.3
0
w ay
PLA onew ay
compost.
PLA onew ay incin.
GLASS
ref illable
PET ref illable
Tap
Tap surf ace
groundw ater w ater
Figure E.16: Results of the sensitivity on the allocation of consumer purchasing trip burdens on the abiotic
depletion and the eutrophication impact indicators in the comparison among the investigated scenarios
418
Appendix E
Abiotic depletion
g Sb eq./F.U.
250
200
196.6
150
209.4
190.3
184.3
201.6
126.8
100
50
145.8
79.7
25.9
0
w ay
PLA onew ay
compost.
PLA onew ay incin.
Tap
Tap surf ace
refillable
groundw ater w ater
21.9
Eutrophication
g PO43- eq./F.U.
40
37.1
30
35.9
25.2
20
16.4
10
15.9
15.3
0.94
3.3
10.3
0
w ay
PLA onew ay
compost.
PLA onew ay incin.
GLASS
ref illable
PET ref illable
Tap
Tap surf ace
groundw ater w ater
0.77
Figure E.17: Results of the sensitivity on dishwashing burdens on the abiotic depletion and the eutrophication
impact indicators in the comparison among the investigated scenarios
419
Appendix E
Abiotic depletion
239.0
g Sb eq./F.U.
250
200
196.6
150
209.4
190.3
184.3
201.6
145.8
126.8
100
73.2
50
25.9
0
w ay
PLA onew ay
compost.
PLA onew ay incin.
31.8
Tap
Tap surf ace
refillable
groundw ater w ater
Eutrophication
g PO43- eq./F.U.
40
37.1
30
35.9
25.2
20
16.4
10
16.8
15.9
15.3
10.3
0.94
0
w ay
PLA onew ay
compost.
PLA onew ay incin.
GLASS
ref illable
5.2
2.3
PET ref illable
Tap
Tap surf ace
groundw ater w ater
Figure E.18: Results of the sensitivity on transport distance from public fountains to consumers houses on the
abiotic depletion and the eutrophication impact indicators in the comparison among the investigated scenarios
(the dotted area in the tap surface water bar specifies the contribution given by water transportation by car)
420
Appendix E
Abiotic depletion
g Sb eq./F.U.
250
200
196.6
150
209.4
190.3
184.3
201.6
145.8
137.3
126.8
100
50
25.9
0
w ay
PLA onew ay
compost.
PLA onew ay incin.
Tap
Tap surf ace
refillable
groundw ater w ater
Eutrophication
g PO43- eq./F.U.
40
37.1
30
35.9
25.2
20
16.4
10
10.3
15.9
15.3
9.4
0.94
0
w ay
PLA onew ay
compost.
PLA onew ay incin.
GLASS
ref illable
PET ref illable
Tap
Tap surf ace
groundw ater w ater
Figure E.19: Results of the sensitivity on the typology of reusable containers utilised in the surface water
scenario on the abiotic depletion and the eutrophication impact indicators in the comparison among the
investigated scenarios
421
Appendix E
Abiotic depletion
369.6
g Sb eq./F.U.
400
273.3
300
200
100
196.6
156.7
261.0
184.3
144.4
286.1
209.4
169.5
267.0
234.6
201.6
190.3
126.8
150.4
145.8
114.2
70.7
0
w ay
PLA onew ay
compost.
PLA onew ay incin.
25.9
Tap
Tap surf ace
refillable
groundw ater w ater
Eutrophication
49.3
g PO43- eq./F.U.
50
40
37.1
28.7
30
20
10
10.1
52.1
33.1
35.9
27.6
30.7
16.4
48.1
29.5
25.2
15.9
15.3
8.9
11.2
0
w ay
PLA onew ay
compost.
PLA onew ay incin.
GLASS
ref illable
6.9
0.94
10.3
PET ref illable
Tap
Tap surf ace
groundw ater w ater
Figure E.20: Results of the sensitivity on the transport distance from bottling plants to retailers or local
distributors on the abiotic depletion and the eutrophication impact indicators in the comparison among the
investigated scenarios
422
Appendix E
Abiotic depletion
250
g Sb eq./F.U.
201.6
200
196.6
150
209.4
190.3
184.3
180.9
126.8
145.8
100
121.2
50
25.9
0
w ay
PLA onew ay
compost.
PLA onew ay incin.
Tap
Tap surf ace
refillable
groundw ater w ater
Eutrophication
g PO43- eq./F.U.
40
37.1
30
35.9
25.2
23.9
20
16.4
10
15.3
15.9
15.5
0.94
10.3
0
w ay
PLA onew ay
compost.
PLA onew ay incin.
GLASS
ref illable
PET ref illable
Tap
Tap surf ace
groundw ater w ater
Figure E.21: Results of the sensitivity on the number of uses of refillable bottles on the abiotic depletion and the
eutrophication impact indicators in the comparison among the investigated scenarios
423
Appendix E
Abiotic depletion
g Sb eq./F.U.
500
473.6
486.4
461.3
467.3
369.6
400
300
200
100
234.6
196.6
153.3
209.4
184.3
166.1
141.0
126.8
147.0
93.6
0
w ay
PLA onew ay
compost.
PLA onew ay incin.
239.0
201.6
190.3
65.1
145.8
79.7
25.9
64.8
Tap
Tap surf ace
refillable
groundw ater w ater
21.9
Eutrophication
63.4
62.2
g PO43- eq./F.U.
60
50
52.1
42.8
41.6
40
37.1
30
20
30.5
16.4
35.9
33.1
25.2
29.3
10
0
9.8
10.0
8.7
w ay
PLA onew ay
compost.
PLA onew ay incin.
16.8
15.9
15.3
GLASS
ref illable
6.5
3.3
0.94
10.3
4.3
PET ref illable
Tap
Tap surf ace
groundw ater w ater
0.77
Figure E.22: Comparison among all the investigated scenarios of the upper and the lower bound obtained for
the abiotic depletion and the eutrophication impact indicators on the basis of the variation of the parameters
considered during the sensitivity analysis
424
Appendix E
Table E.1: Life cycle impacts of the domestic depuration treatment
Impact
category
Unit
Total
Sub-processes contribution
Treatment
discharged water
(1.2)
Activated carbon
Treatment
Electricity
Global warming kg CO2 eq./F.U.
0.56
life cycle
discharged water
(0.23)
(0.22)
(0.10)
Activated carbon
Treatment
Abiotic
Electricity
g Sb eq./F.U.
14.6
life cycle
discharged water
depletion
(1.6)
(12.5)
(0.50)
Activated carbon
Treatment
Electricity
Eutrophication
g PO43- eq./F.U.
0.36
life cycle
discharged water
(0.070)
(0.25)
(0.043)
(1) The functional unit in the case of the upstream processes can be interpreted as “the delivering of 152.1
litres of drinkable water”
MJ eq./F.U.1
CED
22.9
Activated carbon
life cycle
(17.8)
Electricity
(3.9)
Table E.2: Life cycle impacts of the public treatment of water quality improvement
Impact
category
CED
Global
warming
Unit
MJ eq./F.U.1
kg CO2 eq./F.U.
Total
Sub-processes contribution
15.3
Electricity
(14.8)
Activated
carbon life
cycle
(0.23)
PP pre-filter
life cycle
(0.16)
0.90
Electricity
(0.88)
PP pre-filter
life cycle
(0.0083)
Treatment
discharged
water
(0.0040)
Treatment
discharged
water
(0.048)
Activated
carbon life
cycle
(0.0028)
Treatment
discharged
water
(0.020)
Activated
PP pre-filter
carbon life
g Sb eq./F.U.
6.5
life cycle
cycle
(0.069)
(0.16)
Activated
Treatment
PP pre-filter
Electricity
carbon
life
discharged
Eutrophication
g PO43- eq./F.U. 0.274
life cycle
(0.267)
cycle
water
(0.0016)
(0.0032)
(0.0017)
(1) The functional unit in the case of the upstream processes can be interpreted as “the delivering of 152.1
litres of drinkable water”
Abiotic
depletion
Electricity
(6.3)
425
Appendix E
Table E.3: Life cycle impacts of secondary packaging materials employed in the various analysed systems
Life cycle impacts of secondary packaging materials
One way Refillable glass Refillable PET
Impact category
Unit
systems
system
system
CED
MJ eq./F.U.1
30.5
13.8
12.7
1.5
0.59
0.54
Abiotic depletion g Sb eq./F.U.
12.6
5.6
5.2
3Eutrophication
g PO4 eq./F.U.
0.29
0.16
0.15
1) The functional unit in the case of the upstream processes can be interpreted as “the
delivering of 152.1 litres of drinkable water”
Table E.4: Life cycle impacts of transport packaging materials employed in the various analysed systems
Life cycle impacts of transport packaging materials
One way
Refillable
Refillable
Impact category
Unit
systems glass system PET system
CED
MJ eq./F.U.1
7.6
6.7
6.3
0.6
0.12
0.12
Abiotic depletion
g Sb eq./F.U.
5.3
1.3
1.2
Eutrophication
g PO43- eq./F.U.
0.18
0.02
0.02
1) The functional unit in the case of the upstream processes can be interpreted as
“the delivering of 152.1 litres of drinkable water”
Table E.5: Life cycle impacts of caps employed in the various analysed systems
Impact category
CED
Global warming
Abiotic depletion
Life cycle impacts of caps
HDPE caps Aluminium caps
HDPE caps
Unit
(one way
(Glass refillable (PET refillable
systems)
system)
system)
MJ eq./F.U.1
22.4
8.7
26.5
kg CO2 eq./F.U.
1.08
0.77
1.12
g Sb eq./F.U.
9.4
4.9
10.7
Eutrophication
g PO43- eq./F.U.
0.20
0.27
0.31
(1) The functional unit in the case of the upstream processes can be interpreted as “the
Table E.6: Contributions by sub-processes to the overall impacts of bottling plant operations
Use of
Filler machine
Use of
electricity
washing
lubricating oil
30.7
0.060
0.010
CED
MJ eq./F.U. 1
30.8
(99.8%)
(0.19%)
(0.034%)
1.8
0.0033
0.00018
1.8
(99.8%)
(0.18%)
(0.010%)
13.0
0.025
0.0042
Abiotic depletion g Sb eq./F.U.
13.0
(99.8%)
(0.19%)
(0.032%)
0.55
0.12
0.00033
Eutrophication
g PO43- eq./F.U.
0.67
(82.5%)
(17.5%)
(0.049%)
1) The functional unit in the case of the upstream processes can be interpreted as “the
Impact category
Unit
Total
426
Appendix E
Table E.7: Results of the sensitivity on the allocation of consumer purchasing trip burdens on the abiotic
depletion and the eutrophication impact indicators for the interested scenarios
Abiotic depletion (g Sb eq./F.U.)
one-way
one-way
compost.
incin.
Base case
MIN impact
% min
MAX impact
% max
Base case
MIN impact
% min
MAX impact
% max
196.6
184.3
209.4
190.3
193.1
180.8
205.9
186.8
-1.8
396.9
-1.9
384.6
-1.6
-1.8
409.7
390.6
101.9
108.7
95.7
105.3
3Eutrophication (g PO4 eq./F.U.)
one-way
one-way
compost.
incin.
16.4
15.3
37.1
35.9
16.2
15.1
36.8
35.6
-1.5
30.5
-1.6
29.4
85.5
91.9
-0.7
-0.7
51.1
49.9
37.9
39.2
Table E.8: Results of the sensitivity on dishwashing burdens on the abiotic depletion and the eutrophication
impact indicators for the tap groundwater scenario
Abiotic depletion
Eutrophication
(g Sb eq./F.U.)
(g PO43- eq./F.U.)
Tap groundwater scenario
Base case
(every 4 uses/30 items)
MIN impact
(every 5 uses/50 items)
% min
MAX impact
(after each use/15 items)
% max
25.9
0.9
21.9
0.8
-15.4
79.7
-18.4
3.3
207.6
247.1
Table E.9: Results of the sensitivity on transport distance from public fountains to consumers houses on the
abiotic depletion and the eutrophication impact indicators for the tap surface water scenario
Base case (5.5 km)
MIN impact (2 km)
%min
MAX impact (10 km)
%max
Abiotic depletion
Eutrophication
(g Sb eq./F.U.)
(g PO43- eq./F.U.)
145.8
10.3
73.2
5.2
-49.8
-49.6
239.0
16.8
64.0
63.7
427
Appendix E
Table E.10: Results of the sensitivity on the typology of reusable containers utilised in the surface water
scenario on the abiotic depletion and the eutrophication impact indicators for the tap surface water scenario
Abiotic depletion (g
Eutrophication
Sb eq./F.U.)
(g PO43- eq./F.U.)
Base case
(use of glass bottles)
MIN impact
(use of PET bottles)
%min
145.8
10.3
137.3
9.4
-5.8
-8.2
Table E.11: Results of the sensitivity on the transport distance from bottling plants to retailers or local
distributors on the abiotic depletion and the eutrophication impact indicators for the interested scenarios
Virgin
PLA onePLA
PET
way
one-way GLASS
R-PET
PET
one-way one-way compost.
incin.
refillable refillable
Base case
(300 km)
Min impact
(40 km)
%min
Max impact
(800 km)
%max
Base case
(300 km)
Min impact
(40 km)
%min
Max impact
(800 km)
%max
196.6
184.3
209.4
190.3
201.6
126.8
156.7
144.4
169.5
150.4
114.2
70.7
-20.3
273.3
-21.6
261.0
-19.0
286.1
-21.0
267.0
-43.3
369.6
-44.2
234.6
39.0
41.6
36.6
40.3
83.3
85.0
3Eutrophication (g PO4 eq./F.U.)
Virgin
PLA onePLA
PET
R-PET
way
one-way GLASS
PET
one-way one-way compost.
incin.
16.4
15.3
37.1
35.9
25.2
15.9
10.1
8.9
30.7
29.5
11.2
6.9
-38.7
28.7
-41.6
27.6
74.5
-17.2
49.3
80.1
-17.8
48.1
33.1
-55.4
52.1
34.2
106.6
-56.4
33.1
108.5
Table E.12: Results of the sensitivity on the number of uses of refillable bottles on the abiotic depletion and the
eutrophication impact indicators for refillable bottled water scenarios
Abiotic depletion
(g Sb eq./F.U.)
Base case
(10 glass/15 PET)
MIN impact
(50 glass/25 PET)
%min
Eutrophication
(g PO43- eq./F.U.)
GLASS
refillable
PET refillable
201.6
126.8
25.2
15.9
180.9
121.2
23.9
15.5
-10.2
-4.4
-5.1
-2.6
428
Appendix E
Table E.13: Comparison among all the investigated scenarios of the upper and the lower bound obtained for the
abiotic depletion and the eutrophication impact indicators on the basis of the variation of the parameters
considered during the sensitivity analysis
PLA
Virgin
PLA
Tap
R-PET one-way
GLASS
PET
PET
one-way
groundwate
one-way compost
one-way
incin.
r
.
Base
case
Lower
bound
%min
Upper
bound
%ma
x
Base
case
Lower
bound
%min
Upper
bound
%ma
x
Tap
surface
water
196.6
184.3
209.4
190.3
201.6
126.8
25.9
145.8
153.3
141.0
166.1
147.0
93.6
65.1
21.9
64.8
-22.0
473.6
140.9
-23.5
461.3
-20.7
486.4
-22.8
467.3
-53.6
369.6
-48.6
234.6
-15.4
79.7
-55.6
239.0
150.3
132.3
145.6
83.3
85.0
207.6
64.0
Eutrophication (g PO43- eq./F.U.)
PLA
Virgin
one-way
PLA
Tap
Tap
PET
R-PET compost one-way GLASS
PET
groundwate surface
one-way one-way
.
incin.
r
water
16.4
15.3
37.1
35.9
25.2
15.9
0.9
10.3
9.8
8.7
30.5
29.3
10.0
6.5
0.8
4.3
-40.2
42.8
160.0
-43.2
41.6
172.0
-17.8
63.4
71.0
-18.4
62.2
73.4
-60.5
52.1
106.6
-59.0
33.1
108.5
-18.4
3.3
247.1
-57.8
16.8
63.7

politecnico di milano prevention activities in lca of municipal waste

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