IMPROVING DISINFECTION EFFICIENCY IN SMALL DRINKING WATER TREATMENT PLANTS Water Research Commission

IMPROVING DISINFECTION EFFICIENCY IN SMALL DRINKING
WATER TREATMENT PLANTS
Report to the
Water Research Commission
by
MNB Momba†, CL Obi♠ and P Thompson♣
†
Department of Environmental, Water and Earth Sciences, Tshwane University of Technology,
Arcadia Campus, P/Bag X680, Pretoria 0001
♠
School of Agricultural and Life Sciences, University of South Africa, Sunnyside Campus,
Pretoria, PO Box 392, UNISA 0003, South Africa
♣
Umgeni Water, PO Box 30800, Mayville 4058
WRC Report No 1531/1/08
ISBN 978-1-77005-683-1
Set No 978-1-77005-682-4
JULY 2008
This report forms part of a series of two reports. The other report is Guidelines for the Improved
Disinfection of Small Water Treatment Plants (WRC Report TT 355/08).
DISCLAIMER
This report has been reviewed by the Water Research Commission (WRC) and approved for
publication. Approval does not signify that the contents necessarily reflect the views and policies of
the WRC, nor does mention of trade names or commercial products constitute endorsement or
recommendation for use
ii
EXECUTIVE SUMMARY
1.
BACKGROUND OF THE STUDY AND PROBLEM STATEMENT
In South Africa, water infrastructure is well developed in urban areas as opposed to rural areas
where the infrastructure is either poorly developed or non-existent. Supply of water to rural
communities is usually effected through small water treatment plants. Small water treatment plants
(SWTPs) are defined as water treatment systems that are installed in areas which are not well
serviced and which do not normally fall within the confines of urban areas. They include water
supplies from boreholes and springs that are chlorinated, treatment plants of small municipalities
and establishments such as rural hospitals, schools, clinics and forestry stations. However, the
efficacy of drinking water treatment by small water treatment plants is fraught with several
technical and management problems. This is corroborated by the extensive documentations on the
supply of water of poor microbiological quality which is unsafe for human consumption in different
provinces of South Africa.
In order to unravel the intricacies around the operational and management parameters
impinging on the disinfection efficiency of small water treatment plants and to ensure sustainability
of potable water supply to rural communities, this study involved 181 small water treatment plants
across seven provinces of South Africa. The goal was to determine the nature and full extent of the
problems and provide practical and user-friendly guidelines for intervention.
2.
PROJECT OBJECTIVES
The objectives of the project were as follows:
š
To identify and characterize the various types of disinfection equipment currently employed
at small water treatment systems, as well as systems that could potentially be used.
š
To identify the means of disinfection (i.e. the physical and/or chemical processes) employed
at these systems, as well as the performance, chemical and electrical inputs, and ongoing
maintenance requirements of each type.
š
To identify or determine the current quality of treated water, procedures followed to monitor
and control the disinfection processes and the adequacy and consistency of the levels of
iii
disinfectant added. To identify the frequency and adequacy of microbiological tests
performed on the final treated water.
š
To identify the main reasons for disinfection problems experienced at small water systems –
both technical and non-technical.
š
To estimate the cost of drinking water disinfection appropriate for the required standards in
water sector using the required equipment, instrumentation and manpower.
š
To identify major problems resulting in water quality changes in the distribution system by
conducting a comprehensive study in the Fort Beaufort, Seymour and Alice distribution
systems.
š
To provide guidelines for the improved disinfection of final water at small water treatment
plants which also include installation and operating costs for the different disinfection
systems and chemicals.
3.
METHODOLOGY
In order to collect sufficient data on technical and management issues of small water treatment
plants in South Africa, a detailed survey of 181 small water treatment plants across seven provinces
was conducted. The seven provinces namely Limpopo, Mpumalanga, North-West, Free State,
KwaZulu-Natal, Eastern Cape and Western Cape were selected on the basis of familiarity with the
areas, economic status and rural areas experiencing technical and management problems. The
geographic position system (GPS) co-ordinates of each site were logged during the survey to
facilitate future incorporation into a geographical information system (GIS) that is being developed
for the country. On-site visits of small water treatments plants in the designated provinces were
conducted from June 2004 to December 2005. Wherever possible, some plants were visited at least
twice during the study period. The methodology was two-pronged: use of a questionnaire and visual
inspection, and determination of physicochemical and microbiological quality of drinking water.
The questionnaire was used to gather information on the ownership and design capacity of
each water treatment plant, the type of raw water sources and related characteristics, various
methods of water treatment, the equipment currently employed, the performance of the plants,
knowledge and skills of the operators as well as other technical and management issues.
Physico-chemical and microbiological analyses of water samples collected from the raw
water and final water at the points of treatment and consumption were performed using standard
iv
methods. Briefly, the chlorine residual concentrations and pH, the temperature, the turbidity and the
conductivity of water samples were measured on-site using a multi-parameter ion specific meter
(Hanna-BDH laboratory supplies), thermometer, microprocessor turbidity meter (Hanna
instruments) and conductivity meter (Hanna instruments) respectively. Total and faecal coliforms
were used to monitor bacteriological quality as stated in the South African National Standards
(SANS 241:2005) and South African Water Quality Guidelines for Domestic Use (DWAF, 1996;
Water Research Commission, 1998).
To identify the major problems resulting in water quality changes in distribution systems, an
on-site evaluation of the operating conditions at Fort Beaufort, Seymour and Alice water treatment
plants in the Eastern Cape Province was conducted. This commenced with a reconnaissance visit to
the plants and the network of smaller reservoirs in villages that were serviced by these plants. The
relationship between the performance of the plant dosing systems and the water quality in the bulk
distribution systems was established. To ensure effective free residual chlorine throughout the
reticulation systems and the consumer’s taps, the chlorine dosages applied at the dosing points in
each plant were assessed. The sampling regime for bacteriological quality of drinking water was
designed to include points furthest to the satellite reservoirs servicing specific villages in order to
provide a broad overview of the quality compliance of the water that got to the end users at these
locations. The evaluation of these water treatment plants and their reticulation systems was
performed from October to November 2005.
4.
SUMMARY OF MAJOR FINDINGS AND CONCLUSIONS REACHED
Small water treatment plant ownership – Four categories of the plant ownership were identified,
viz Local/District Municipality, Department of Water Affairs and Forestry (DWAF), Department of
Health (DOH) and Water Board (private company). Overall, 81% of the small water treatment
plants surveyed in South Africa were owned by Local/District Municipality.
Design capacity of small water treatment plants – The capacity of the plants surveyed during the
investigation varied between 0.3 ML/d and 120 ML/d. Most of the plants were operating below the
design capacity.
Type of raw water sources – Overall 86% of the small water treatment plants surveyed abstracted
their raw water from surface water, 10% used groundwater and 4% a combination of both water
sources.
v
Water treatment practices – Conventional water treatment processes were generally used in the
majority of the plants surveyed. In terms of coagulation, it was noted that polyelectrolyte (66%)
was commonly used, followed by alum (18%) and ferric chloride (6%). Sixty percent of the small
water treatment plants used rapid gravity filtration system while a further 24%, 9% and 2% of the
plants made use of pressure filters, slow sand filtration and diatomaceous earth filters in that
respective order. Chlorine gas was found to be the most popular disinfectant (69%), followed by
sodium hypochlorite (15%) and calcium hypochlorite (HTH) (14%), among others.
Physicochemical quality compliance – All water samples collected at various plants fell within
SANS 241:2005 Class I in terms of pH (5 to 9.5) and conductivity (< 150 mS/m).
Turbidity – At the point of treatment, 44% and 38% of the small water treatment plants surveyed in
South Africa fell within SANS turbidity Class I (<1 NTU) and Class II (1-5 NTU), respectively. At
the point of consumption, 46% and 41% of the plants fell within Class I and Class II, respectively.
The highest turbidity compliance (Class I: 69-73%, Class II: 27 -31%) was noted in the Free State
and the lowest turbidity compliance (Class I: 27-33%, Class II: 24-45%) was recorded in the
Eastern Cape Province.
Chlorine residual – Overall, the small water treatment plants surveyed had drinking water with free
chlorine residual concentrations ranging between ≤ 0.1 and ≤ 0.5 mg/L. In most cases, the flow rate
of the water and the initial chlorine dose were not known, resulting in under-chlorinated drinking
water. During the on-site evaluation of the operating conditions at Fort Beaufort, Seymour and
Alice water treatment plants, the following major problems impacted on the effectiveness of the
disinfection process in the distributions: i) the distribution systems of the pipe network did not show
acceptable levels of residual chlorine while the plant chlorination systems gave adequate dosage at
the dosing points; ii) most of the chlorine dosed at the treatment plants was consumed by the floc
sludge that accumulated in the reservoirs and the deposits that were present in the distribution
networks .
Microbiological compliance – For coliforms, 67% and 72% of the plants complied with the South
African drinking water recommended limits for total coliforms and faecal coliforms at the point of
treatment, respectively. The Eastern Cape Province produced the lowest drinking water quality in
vi
terms of both total (28% of the plants) and faecal (34% of the plants) coliforms while the Free State
produced the best water quality (100% compliance).
Control and monitoring – Generally, 50% of the operators and supervisors interviewed did not
exude knowledge of the flow-rates at which their plants operated and more than 78% were unaware
of the chemical doses used or how to correlate the required dose to the flow rate. In terms of
instrumentation, only 46% of plants surveyed had the instruments to measure turbidity, pH and
chlorine residual. Ninety–five percent of the plants reported that an external monitoring group
visited the plants approximately once a month; however most plants complained about a lack of
feedback.
Non technical (management) aspects – Non technical issues affecting the efficiency of water
supply by small water treatment plants included: inadequate training of manpower, poor
maintenance practices, poor working conditions, insufficient financial capacity, poor recording,
poor documentation and communication of data and information, as well as inadequate community
involvement.
Estimated cost of chlorination – The survey indicated that chlorine was commonly used in small
water treatment plants. To improve the chlorination efficiency in water sector, this study suggests
the following estimated costs for chlorine gas, sodium hypochlorite, and calcium hypochlorite,
which are commonly used in rural small water treatment:
Cost Comparison of Disinfection Alternatives
Gas/liquid
Sodium
Calcium
Chlorination
Hypochlorite
Hypochlorite
Capital Cost
R194 800
R317 455
R90 000
Direct Operating Cost c/kl
9.50
33.86
17.02
Maintenance c/kl
1.10
1.10
0.55
Total Operating Cost c/kl
13.77
34.79
36.01
For the improved disinfection of final water at small water treatment plants and distribution
systems, a guide document was drawn up. It included practical steps and also installation and
operating costs for the different disinfection systems and chemicals. This guide document is
vii
intended for use at operational and management levels by plant managers, supervisors, plant
operators and plants owners, consultants and Municipal Water Local Authorities.
5.
RECOMMENDATIONS
Small water treatment plants should be equipped with a flow meter, jar stirrer, turbidity meter, pH
meter and a chlorine meter for enhancement of disinfection efficiency.
A programme for monitoring the physicochemical (at least pH, temperature, turbidity and free
chlorine residual) and bacterial (coliform bacteria, especially faecal coliforms) quality of water at
the point of treatment and various sites of the distribution systems should be established.
Regular competency assessments and appropriate training programmes for water service providers
and regulators should be conducted.
The development and implementation of operational checklists and protocols are equally essential
to ensure timely ordering of materials (particularly chemicals) and the maintenance of equipments.
Increased funding of small water treatment plants and enhancement of working conditions of
personnel are also recommended.
6.
RECOMMENDATION FOR FUTURE STUDY
A future investigation has to be conducted on the compliance of non-metropolitan South African
potable water providers with the required management guidelines and norms including reasons for
non-compliance.
viii
7.
LIST OF PRODUCTS
7.1 Book
Momba MNB, Thompson P and Obi CL (2006). Practical and user-friendly guidelines for
improving the efficiency of disinfection in small water treatment plants of South Africa
7.2 Article
Momba MNB, Tyafa Z, Makala N, Brouckaert BM and Obi CL ( 2006 ) Safe drinking water still
a dream in rural areas of South Africa. Case Study: The Eastern Cape Province. Water SA 32 (5):
715-720
Obi CL, Momba MNB, Samie A, Igumbor JO, Green E and Musie E (2007) Microbiological,
physico-chemical and management parameters impinging on the efficiency of small water treatment
plants in the Limpopo and Mpumalanga Provinces of South Africa. Water SA 33(2): 1-9
7.3 Conference Presentation
Obi CL, Samie A, Green E, Musie E, Masebe T, Mashota M, Ndou S, Momba MNB, Thompson P,
Charles K (2004) The efficiency of Disinfection of the Drinking Water in Small Water Treatment
Plants in Limpopo and Mpumalanga Provinces of South Africa: Preliminary report. The 2nd
International Conference on Safe Water, November 4-7, Johannesburg, South Africa.
Z Tyafa, MNB Momba, N Makala, BM Brouckaert and CL Obi (2006) Safe drinking water still a
dream in rural areas of South Africa - Case study: The Eastern Cape Province. The Water Institute
of South Africa, Biennial conference and exhibition, Durban, May, South Africa.
Obi CL, Momba MNB, Samie A, Green E, Musie E, Masebe T, Mashota M, Igumbor JO and Ndou
S (2006) Water Quality Indicator Indices and Management Issues of Small Water Treatment Plants
in Limpopo and Mpumalanga Provinces of South Africa. The International Water Association
World Congress, China, September.
ix
ACKNOWLEDGEMENTS
The following persons and organisations are thanked for their contribution to this report:
Financial Support
Water Research Commission
Members of the Steering Committee
Dr G Offringa
Water Research Commission (Chairman)
Prof D Key
University of Western Cape
Mr C Swartz
Chris Swartz Engineer
Mr K Charles
CSIR
Ms M du Preez
CSIR
Mr M Ramba
Emanti
Mr PL Chimloswa
Amatola Water
Project Team and Technical Support
Prof M Momba
Tshwane University of Technology (Project Leader)
Mr P Thompson
Umgeni Water (Project Team)
Prof CL Obi
University of South Africa (Project Team)
Ms ZN Makala
University of Fort Hare (Project Team)
Ms Tyafa
University of Fort Hare (Project Team)
Mr K Charles
CSIR (Project Team)
Dr A Okoh
University of Fort Hare (Technical Support)
Dr BM Brouckaert University of KwaZulu-Natal (Technical Support)
Mr C Mfenyana
University of Fort Hare (Technical Support)
Miss A Okeyo
University of Fort Hare (Technical Support)
Mr N Sibewu
University of Fort Hare (Technical Support)
Mr A Bosrotsi
University of Fort Hare (Technique Support)
Mr A Samie
University of Venda (Technical Support)
Mr E Green
University of Venda (Technical Support)
Mr E Musie
University of Venda (Technical Support)
Xolani Ngcemu
Umgeni Water (Technical Support)
x
TABLE OF CONTENTS
EXECUTIVE SUMMARY..............................................................................................................................iii
ACKNOWLEDGEMENTS..............................................................................................................................x
LIST OF TABLES..........................................................................................................................................xiv
LIST OF FIGURES.........................................................................................................................................xv
CHAPTER I: GENERAL INTRODUCTION……………..…………………………..…………………….1
CHAPTER II: LITERATURE REVIEW………………….………..……………………………………….4
2.1: BACKGROUND ON RURAL WATER SUPPLY AND SMALL WATER SYSTEMS IN
SOUTH AFRICA ………………………………………………………………………………….4
2.2: GENERIC UNIT PROCESSES AND BARRIERS IN WATER TREATMENT
….……………5
2.2.1: Selection of water sources………………………………………………………………………5
2.2.2: Treatment processes …………………………………………………………………………..6
2.2.2.1: Treatment of surface water ……………………………………………………………….9
2.2.2.2: Treatment of groundwater ………………………………………………………………..9
2.2.2.3: Treatment of spring water ………………………………………………………………...10
2.3: DISINFECTION PRACTICES IN THE PRODUCTION OF POTABLE WATER ………………11
2.3.1: Chemical agents
…………………………………………………………………………….11
2.3.1.1: Chlorine and chlorine based compounds
2.3.1.2: Ozone
…………………………………………....12
…………………………………………………………………………………..17
2.3.1.3: Use of alternative chemical disinfectants…………………………………………………18
2.3.2: Physical agents (Ultraviolet irradiation)……………………………………………………….20
2.3.3: Physical processes……………………………………………………………………...………21
2.4 WATER DISTRIBUTION AND STORAGE……………………………………………………….23
2.5: MICROBIOLOGICAL QUALITY OF THE FINAL WATER & PUBLIC HEALTH
SIGNIFICANCE ……………………………………………………………………………….….24
2.5.1: Monitoring the safety of water supplies
……………………………………………….…25
2.5.2: Quality at water works and in distribution systems…………………………………………….26
2.5.3: Impact of microbiological quality of treated water on public health…………………………...26
2.6: IMPROVING DISINFECTION EFFICIENCY IN SMALL WATER TREATMENT PLANTS.....28
2.6.1: In-service training of water personnel and management…………………………………..…...28
2.6.2: Hygiene education and community based management……………………………………..…29
CHAPTER III: SURVEY OF DISINFECTION EFFICIENCY OF SMALL DRINKING WATER
TREATMENT PLANTS…………………………………………………………………………...31
3.1: SURVEY AREA…………………………………………………………………………………….31
3.2: SURVEY METHODOLOGY……………………………………………………………………….31
3.3: RESULTS OF THE SURVEY AND DISCUSSION………………………………………………..32
xi
3.3.1: Small water treatment plant ownership…………………………………………………………32
3.3.2: Design capacity of small water treatment plants………………………………………………..32
3.3.3: Type of raw water sources………………………………………………………………………34
3.3.4: Water treatment practices……………………………………………………………………….35
3.3.5: Quality of drinking water produced by small water treatment plants……………………….….38
3.3.5.1: Physicochemical compliance……...……………………………………………………….38
3.3.5.2: Microbiological compliance……………………………………………………………….42
3.3.6: Control and monitoring…………………………………………………………………………46
3.4: CONCLUSIONS AND RECOMMENDATIONS FROM THE SURVEY…………………………50
CHAPTER IV: WATER QUALITY CHANGES IN THE DISTRIBUTION SYSTEM…………………...52
4.1: METHODOLOGY………………………………………………………………………………… 52
4.1.1: Measurement of the flow of raw water and coagulant dose………………………………….....52
4.1.2: Physicochemical and Microbiological Analysis
………………………………………….…..53
4.2: RESULTS AND DISCUSSION……………………
…………………………………………..…53
4.2.1: Distribution networks……………………………………………………………………….…..53
4.2.2: Water Treatment Plant operation conditions……………………………………………….…...55
4.2.2.1: Fort Beaufort water treatment plant…………………………………………………….….55
4.2.2.2: Seymour Water Treatment Plant
…………………………………………………….56
4.2.2.3: Alice Water Treatment Plant……………………………………………………………....57
4.2.3: Drinking water quality in the distribution systems……………………………………………..57
4.2.3.1: Turbidity compliance
……………………………………………………….…………...57
4.2.3.2: Free chlorine residual concentration and microbiological characteristics in the distribution
systems………………………………………………………………………………..........59
4.3: CONCLUSIONS………………………………...……………………………………………..……63
4.4: RECOMMENDATIONS
……………………………………………………………….….…..63
CHAPTER V: MANAGEMENT ISSUES AFFECTING THE EFFICIENCY OF DISINFECTION IN
SOUTH AFRICAN SMALL WATER TREATMENT PLANTS……………………………….…65
5.1: INTRODUCTION………………………………………………………………………….………..65
5.2: METHODOLOGY……………………………………………………………………….………….65
5.3: RESULTS AND DISCUSSION…………………………………………………………….…….....66
5.3.1: Poor Maintenance Practices…………………………………………………………….……….66
5.3.2: Training and Capacity Building…………………………………………………….…………...67
5.3.3: Poor Working Conditions……………………………………………………………………….68
5.3.4: Insufficient financial capacity…………………………………………………………………...68
5.3.5: Inadequate community involvement…….....................................................................................69
5.3.6: Streamlining Duties and Job Description……………………………………………………..…69
xii
5.3.7: Poor Recording, Documentation and Communication ……………………………………….....71
5.3.8: Emergency plans….......................................................................................................................71
5.4 :RECOMMENDATIONS………………………………………………………………………………..72
CHAPTER VI: GENERAL CONCLUSIONS AND RECOMMENDATIONS…………………………….82
REFERENCES……........................................................................................................................................84
APPENDIXES……………………………………………………………………………………………….89
xiii
LIST OF TABLES
Table 2.1
Water sources and potential health hazards ……………………………………….6
Table 2.2
Typical treatment steps in potable water production ……………………………….8
Table 2.3
Chloramine formation ………………………………………………………..…….16
Table 2.4
Membrane process classification
Table 2.5
Impact of poor water quality on human health (2001-2005) ………………..…….27
Table 3.1
Example of a process control shift log sheet ………………………………..…….49
Table 3.2
Example of filter washing and clarifier solids management ………………..…….49
Table 3.3
Example of daily operator log………………………………………………..…….50
Table 5.1
Some non-technical issues impacting on quality of water services delivery in small
………………………………………..…….23
water treatment plants in south africa ………………………………………..…….67
Table 5.2
Calcium hypochlorite capital costs………………………………………… …..….73
Table 5.3
Calcium hypochlorite operating costs…………………………………………..….74
Table 5.4
Total operating costs for calcium hypochlorite dosing system…………….............74
Table 5.5
Design of typical sodium hypochlorite dosing system
Table 5.6
Operating costs of typical sodium hypochlorite dosing system
Table 5.7
Fixed capital and annual operating costs of sodium hypochlorite dosing system….77
Table 5.8
Gas chlorination operating costs
Table 5.9
Gas chlorination system – capital cost
...........................................................79
Table 5.10
Total operating costs for gas chlorinator
...........................................................80
Table 5.11
Cost comparison of disinfection alternatives ...........................................................80
Table 5.12
Allocation of duties and responsibilities for personnel in water sector
...................................75
.......................76
.......................................................................78
xiv
...........81
LIST OF FIGURES
Fig 2.1
Schematic of a Conventional Water Treatment Plant ……………………………………….7
Fig. 3.1
Category of Ownership of Small Treatment Plants surveyed in South Africa
……….34
Fig. 3.2
Types of Water Sources in Small Treatment Plants surveyed in South Africa
……….35
Fig. 3.3
Types of Coagulants used in Small Treatment Plants Surveyed in South Africa
……….37
Fig. 3.4
Types of Filters used in Small Treatment Plants surveyed in South Africa ………………..37
Fig. 3.5
Types of Disinfectants used in Small Treatment Plants in South Africa
Fig. 3.6
Turbidity Compliance of Small Treatment Plants surveyed in South Africa at
………………..38
the Point of Treatment …………………………………………………………………….39
Fig. 3.7
Turbidity Compliance of Small Treatment Plants Surveyed in South Africa
in Distribution system …………………………………………………………………….40
Fig. 3.8
Free Chlorine per Province at Point of Use and Point of Treatment
………………..41
Fig. 3.9
Free Chlorine Histogram for all Provinces at Point of Treatment ………………………...41
Fig. 3.10
Free Chlorine Histogram at Point of use across all Provinces
Fig. 3.11
Bacteriological Compliance at the Point of Treatment
…………………………………44
Fig. 3.12
Bacteriological Compliance in Distribution System
…………………………………45
Fig. 4.1
Schematic Diagrams of Fort Beaufort Distribution Network………………………………54
Fig. 4.2
Schematic Diagrams of Alice Distribution Network
Fig. 4.3
Fort Beaufort Turbidity Histogram
Fig. 4.4
Histogram of Turbidity in Seymour Distribution System …………………………………58
Fig. 4.5
Histogram of Turbidity in the Alice Drinking Water Distribution System………………...58
Figs. 4.6-4.9
Histogram of the Free Chlorine Residual and Indicator Bacteria in the Fort Beaufort
………………………...42
……………………………………55
…………………………………………………..58
Drinking Water Distribution System.....................................................................................60
Figs 4.10-4.13 Histogram of the Free Chlorine Residual and Indicator Bacteria in the Seymour
Drinking Water Distribution System......................................................................................61
Figs 4.14-4.17 Histogram of the Free Chlorine Residual and Indicator Bacteria in the Alice
Drinking Water Distribution System.....................................................................................62
Fig 5.1
Organogram of for Water Service management....................................................................70
xv
xvi
CHAPTER I
GENERAL INTRODUCTION
The main objective of water supply systems is to provide consumers with drinking water that is
sufficiently free of microbial pathogens to prevent waterborne diseases.
In addition to this
requirement, water purification for domestic use must produce an aesthetically acceptable (in terms
appearance, taste and odour) and chemically stable water (i.e. it must not case corrosion or form
deposit in pipes or fixtures such as geysers). The key to produce water of such desired quality is to
implement multiple barriers, which control microbiological pathogens, and chemical contaminants
that may enter the water supply system. This includes adopting sound management practices and
continuously reviewing both the state of the water treatment and the distribution infrastructure, and
the quality of the water produced.
Microbial pathogens which include bacteria, viruses and protozoan parasites can be
physically removed as particles in many individual water treatment processes such as coagulation,
flocculation, sedimentation and filtration (also called unit processes and unit operations) or
inactivated in disinfection processes. Application of a disinfection barrier is a critical component of
primary treatment of drinking water (LeChevallier, 1998). Disinfection is important because the
turbidity removal by sedimentation and filtration does not remove all microbial pathogens from
water. The disinfectant residual in the drinking water distribution system is also one of the key
factors controlling the microbial quality of water, preventing bacterial proliferation in the water
phase (regrowth) and limiting viability of bacteria released from pipe wall biofilms (Momba and
Makala, 2004).
The practice of disinfection of water supplies has been, in general, used since the beginning
of the century and has given rise to substantial reduction in the occurrence of water-related diseases.
The most commonly used technology to achieve disinfection has been chlorination. This method of
disinfection has been proved to be reliable, appropriate and effective worldwide (Solsona and
Pearson, 1995). In South Africa, the larger cities that are supplied with water from waterworks that
are managed by Water Boards and Metropolitan Councils generally have high quality potable water
(Nevondo and Cloete, 1999). Although, chlorination is commonly used in the majority of South
African rural water treatment plants, recent studies have shown that these plants do not produce the
quality or quantity of drinking water that they were designed to produce (MacKintosh and Colvin,
2002; Momba et al., 2004a; 2004b). Small water systems have difficulty in complying with the
ever-expanding number of regulations or applying the best available technology due to poor
1
financial management, inadequate capital funding and limited technical capacity (Swartz, 2000;
Momba et al., 2005).
There are three major inter-related challenges facing small water systems that need to be
addressed: i) financing, ii) lower-cost technology and iii) sustainability. For example, a water
treatment technology is appropriate if it has a relatively lower capital or operation and maintenance
cost, it is simpler to operate, it is convenient to monitor and produces fewer disinfection byproducts. The concept of sustainability is important because it focuses on the underlying causes of
most problems experienced by small water systems. A major issue that has not been resolved for
small systems is the inability to develop and evaluate low-cost treatment technologies. Complex
technologies that require a higher level of operation, education and supervision cannot be easily
applied to small systems. In addition, it has been noticed that the small water systems problems that
are encountered in developing countries are also dominant even in developed countries (USEPA,
1998). In 2000, The Center for Disease Control (CDC) in the United States reported that there were
39 waterborne disease outbreaks; 2.068 illnesses; 122 hospitalizations and 2 deaths. Eighteen (46%)
of the 39 outbreaks were linked to small water systems.
Providing safe drinking water can immediately and dramatically improve the health of many
communities and can also lead to the elimination of diseases. While municipal water treatment has
eliminated threats from many waterborne illnesses of the past, such as cholera and typhoid fever,
outbreaks of waterborne diseases still occur. New pathogens, some of which are resistant to the
conventional treatment processes, continue to emerge (USEPA, 1998). Even with optimum
treatment, contamination can also occur in the water distribution system, leaving the consumer
vulnerable. Attempts at providing safe and adequate quantities of water to the developing regions of
the world must thus be properly integrated with other aspects of development such as sanitation and
education.
PROJECT OBJECTIVES
The project aimed at providing guidelines for the improved disinfection of final water at small
water treatment plants which also include installation and operating costs for the different
disinfection systems and chemicals. To achieve this goal, the following objectives were pursued:
i)
To identify and characterize the various types of disinfection equipment currently
employed at small water treatment systems, as well as systems that could potentially be
used.
ii)
To identify the means of disinfection (i.e. the physical and/or chemical processes)
2
employed at these systems, as well as the performance, chemical and electrical inputs,
and ongoing maintenance requirements of each type.
iii)
To identify or determine the current quality of treated water, procedures followed to
monitor and control the disinfection processes and the adequacy and consistency of the
levels of disinfectants added. To identify the frequency and adequacy of microbiological
tests performed on the final treated water.
iv)
To identify the main reasons for disinfection problems experienced at small water
systems – both technical and non-technical.
v)
To estimate the cost of drinking water disinfection appropriate for the required standards
in water sector using the required equipment, instrumentation and manpower.
vi)
To identify major problems resulting in water quality changes in the distribution system
by conducting a comprehensive study in Fort Beaufort, Seymour and Alice distribution
systems.
3
CHAPTER II
LITERATURE REVIEW
In developing countries, several disease outbreaks are associated with the use of untreated surface
water, contaminated well water, treatment plant deficiencies and contaminated distribution systems.
For the purpose of this study, the first section of this chapter provides information on rural water
supply and water treatment systems, the second section briefly discusses various unit processes and
multiple barriers used in the treatment of each type of water source. The third section, which is the
most important in terms of this investigation, discusses in detail various disinfection practices used
worldwide with emphasis on developing countries and small rural systems. This is followed by an
overview of the process of drinking water distribution and storage (fourth section). The fifth section
deals with the general quality of treated water at the plant and in the distribution system, which
impacts on the health of consumers. Practical strategies, which can lead to improving the
disinfection efficiency in small water treatment plants, are discussed in the sixth section.
2.1
BACKGROUND ON RURAL WATER SUPPLY AND SMALL WATER SYSTEMS
IN SOUTH AFRICA
Generally, water infrastructure in South Africa is well developed in urban areas and the majority of
the urban population utilizes potable water. In rural communities, water infrastructure is either
poorly developed or non existent and the majority of the populace depend on water sources such as
rivers and ponds for their drinking water. These water sources are usually not treated, faecally
contaminated and unsafe for human consumption (Muyima and Ngcakani, 1998; Obi et al., 2002;
2003 a, b; Momba and Kaleni, 2002; Momba and Notshe, 2003; Momba et al., 2005a; Momba et
al., 2006).
Contaminated water sources are vehicles for the transmission of waterborne diseases such as
cholera, shigellosis and Campylobacteriosis (Ashbolt, 2004; Momba et al., 2006). The World
Health Organization (WHO) estimated that about 1.1 billion people globally drink unsafe water and
the vast majority of diarrhoeal diseases in the world (88%) are attributable to unsafe water,
sanitation and hygiene. Approximately 3.1% of annual deaths (1.7 million) and 3.7% of the annual
health burden (disability adjusted life years [DALYs]) world-wide (54.2 million) are attributable to
unsafe water, sanitation and hygiene (WHO 2003). In order to prevent waterborne diseases, water
4
is treated to eliminate pathogens. In rural and peri-urban areas, water sources are usually treated in
units called Small Water Treatment Plants (SWTPs).
Small water treatment plants are defined as water treatment systems that are installed in
areas, which are not well serviced, and which do not normally fall within the confines of urban
areas. They are therefore mostly plants in rural and peri-urban areas and include water supplies
from boreholes and springs that are chlorinated, small treatment systems for rural communities,
treatment plants of small municipalities and treatment plants for establishments such as rural
hospitals, schools, clinics and forestry stations. Most of these applications fall within the category
of small plants of less than 2.5 Ml/d, although larger capacity plants operating in poorly serviced
areas also fall into this category for purposes of this study. The following section briefly discusses
the unit processes and multiple barrier strategy.
2.2
GENERIC UNIT PROCESSES AND BARRIERS IN WATER TREATMENT
The primary purpose of water treatment is to render the water fit for human consumption. This
requires the improvement of microbiological quality and the control of dangerous chemical
substances and metals. Secondary purposes include the protection of distribution and plumbing
systems and the maintenance of aesthetic quality (e.g. taste, odour, colour and hardness) (WHO,
1982). Meeting the goal of clean, safe drinking water requires a multi-barrier approach that
includes: protection of source water from contamination, appropriately treating raw water and
ensuring safe distribution of treated water to consumer taps. The treatment requirement for potable
water supply in rural areas will therefore depend on water quality required and the quantity, and
variation in quality of the source.
2.2.1
Selection of water sources
Rational selection requires a review of the alternative sources available and their respective
characteristics. Factors to consider when selecting a water supply source include: i) safe yield, ii)
water quality, iii) collection requirements, iv) treatment requirements, v) transmission and
distribution requirements. The ability of water sources to provide both quality and quantity
requirements must be considered. Although the quality of water is variable from source to source,
surface waters have qualities in common. Likewise, groundwater supplies have many similar
characteristics. Table 2.1 shows the range of water sources together with the ingredients that may be
present in each.
5
TABLE 2.1
WATER SOURCES AND POTENTIAL HEALTH HAZARDS
Source
Potential health hazards
Deep groundwater (boreholes)
Fe, Mn, Colour, H2S, NO3, NH4, CO2 (pH)
Shallow groundwater
Fe, microorganisms, NO3, NH4
Infiltration water
Fe, colour, organic matter, taste
Spring waters
Fe, CO2 (pH)
Rainwater (cisterns)
Microorganisms, constituents of atmospheric pollution, pH
Surface water (streams, rivers, lakes and
Suspended solids, microorganisms, colour, algae, taste,
reservoirs)
odours, organic matter, NO3, NH3
Source (WHO, 1982)
In a water scarce country such as South Africa, the selection of water sources may pose a problem.
Nevertheless, groundwater sources, which remain the main water supply for many rural small
communities, must be considered as a first priority due to the fact that many small villages are
geographically scattered. Although the use of groundwater source supply will reduce the cost of
water treatment, the removal of nitrate and the disinfection process must be taken into account.
When small streams, open ponds, lakes, or open reservoirs must be used as sources of surface water
supply, the danger of contamination and of consequent spread of enteric diseases such as typhoid
fever and dysentery are increased. As a rule, surface water should be used only when groundwater
sources are not available or are inadequate. The physical and bacteriological contamination of
surface water makes it necessary to regard such sources of water supply as unsafe for domestic use
unless reliable treatment, including filtration and disinfection, is provided (Anon, 1995). The
treatment of surface water to ensure a constant, safe supply requires diligent attention to operation
and maintenance by the owner of the system.
2.2.2
Treatment processes
The need for reduction of microbial and chemical ingredients will depend on their initial
concentrations and the target quality. It must be recognized, however, that a treatment process that
may be appropriate for use under certain conditions may not be necessary appropriate elsewhere. It
will depend on the quality and availability of operator skills and on the availability of other
resources such as materials and electricity (WHO, 1982). Treatment practices vary from system to
system but there are five generally accepted basic techniques: coagulation, flocculation,
sedimentation, filtration and disinfection. After treatment, the drinking water flows into the
6
distribution system. These typical treatment steps are summarized in Fig. 2.1 and Table 2.2
describes the purpose of each step.
The incidence for waterborne disease associated with protozoan parasites (Giardia or
Cryptosporidium) and the resistance of some pathogens to conventional disinfection presents a
challenge to the water industry. Because of its resistance to chlorination and its small size, making it
difficult to be removed by filtration, Cryptosporidium represents a unique challenge to drinking
water industry. Use of a single barrier such as disinfection alone, or operation of a conventional
treatment plant that had not been optimized has contributed to several disease outbreaks (USEPA,
1998). A multiple barrier approach (which involves a number of physical and chemical removal
processes) is recommended for the optimal removal of Giardia or Cryptosporidium.
Chemical Addition
and Flash Mixing
Abstraction
Raw Water
Storage Tank
coagulant
pH
adjustment
Flocculation
Flow Splitting
F1
pre-oxidation
recycle stream
F4
Settling
Tanks
sludge
Sludge
Settling
Pond
backwash water
Filters
On-site Finished Water Reservoir
F3
F2
post-disinfectant
Fig. 2.1 Schematic of a conventional water treatment plant (Momba and Brouckaert, 2005)
Disinfection methods that involve chemical and physical processes such as gravity separation
(sedimentation and flotation) and filtration treatment barriers for the removal of pathogens and
especially protozoa will be discussed in section 2.3 of this chapter.
7
TABLE 2.2
TYPICAL TREATMENT STEPS IN POTABLE WATER PRODUCTION
Step
Pre-
Description
Purpose
Addition of chlorine to the raw water.
chlorination
Remove of colour, iron and/or manganese.
Prevent biofilm growth in channels, settling
tanks and filters.
pH
Addition of chemicals such as lime, soda ash
Adjust the pH to fall in a required range for
adjustment/
or carbon dioxide which change the pH.
good floc formation and/or to prevent
stabilisation
corrosion or excessive scaling in the
distribution system.
Coagulation
Flocculation
Settling
Addition and flash mixing of coagulants (also
Add chemicals which produce floc. Floc
called flocculants) such as alum and/or
contains many of the contaminants present
polymer solutions to raw water.
in the original raw water.
Formation of floc in channels or pipes between
Form flocs which are easily removed in the
coagulant addition and the settling tanks.
settling tanks.
Floc sinks to the bottom of the settling tank
Removal of floc formed in coagulation and
while settled water flows over the top into the
flocculation steps.
settled water channels.
Filtration
Water is filtered through a granular media
Removal of floc or particles not removed in
(sand and/or anthracite).
the settling tanks.
Disinfection/
Addition of chlorine to the filtered water or
Kill off any microbes in the filter water and
post-
Final water storage reservoir.
provide chlorine residual to prevent later re-
chlorination
infection.
Finished
After disinfection, the treated water flows to a
Allow sufficient time for the chlorine to act
water
storage reservoir on or near the plant.
and ensure an adequate supply of water
storage
during
periods
of
high
demand
or
disruptions to the operation of the plant.
Sludge
Dirty backwash and or sludge from the settling
Reduces water losses on the plant and
settling
tanks is held in settling ponds where the sludge
avoids
and
settles to the bottom of the ponds and the
backwash water to either natural water
washwater
supernatant is recycled to the top of the plant.
bodies (which is illegal) or to the sewer
recovery
discharging
sludge
(which requires a permit).
Source: Momba and Brouckaert, 2005
8
and
spent
2.2.2.1
Treatment of surface water
Surface water can be divided into rivers, streams, lakes, small dams and ponds. These water sources
are subjected to frequent dramatic changes in microbial quality as a result of a variety of activities
on a watershed. Consequently any surface water source must be either well protected or treated
before it can be used for drinking. For small communities, it is generally preferable to protect
groundwater source that requires little or no treatment than to treat surface water that has been
exposed to faecal contamination. In many circumstances, however, surface water is the only
practicable source of supply and requires affordable treatment and disinfection (WHO, 1997).
Surface water may contain organic and mineral particulate matter that could harbour
protozoan parasites such as Cryptosporidium parvum and Gardia lambia (Chlorine Chemistry
Council, 2003). The aim of surface water treatment is to achieve the required standard of final water
quality regardless of the quality of the intake source water. However, the extent of water treatment
for domestic use depends on the source water quality. Some sources such as a river require more
extensive treatment. Consequently the treatment will involve two types of processes: physical
removal of solids (mainly minerals and organic particulate matter) and chemical disinfection
(killing or inactivating microorganisms).
2.2.2.2
Treatment of groundwater
Groundwater is the water that is found in cracks and spaces in soil, sand and rocks. The area where
the water fills these spaces is called a saturated zone. It can be found almost everywhere.
Groundwater consists of wells and boreholes. Wells are suitable when they are located near the
surface aquifers and weathered materials and where the population is widely dispersed. Most wells
need an inner lining, which provides protection against caving and helps to prevent polluted water
from seeping in from the surface. Boreholes are suited for low volume water supplies (Momba,
1997; Ndaliso, 2000). Groundwater is one of the primary sources of potable water in developing
areas. In South Africa, more than 280 towns and villages derive their water supply from
groundwater. Groundwater therefore accounts for 15% of water supply (Momba, 1997).
Groundwater is usually bacteriologically safe unless a contaminant source exists nearby.
Contaminants such as organic and inorganic particles collected during its flowpath are removed
or degraded by filtration, oxidation, adsorption, cation exchange and dilution. Frequently
encountered problems include excessive fluoride, iron, manganese, hardness and salts. The most
common treatment is oxidation by aeration followed by sedimentation and chlorination, or if iron
content is high, by aeration followed by sedimentation and rapid sand filtration. Slow sand filtration
9
is also effective at treating groundwater with iron and sulphate. Manganese removal may be
improved by chlorination prior to filtration. The removal of Nitrate and nitrite should be considered
together because conversion from one form to the other occurs in the environment. It is of primary
health concern as nitrite causes methanoglobinaemia, which is particularly dangerous to infants
under the age of 3 years. The maximum recommended value for South Africa is a total nitrite and
nitrate of 6 mg/l, expressed as nitrogen (DWAF, 1996). However, some dissolved minerals may not
be removed, and chemical reactions related to the geologic nature of the aquifers may also be a
problem. The character of groundwater changes only slowly with time so that terminating the cause
of contamination will not restore its quality for an indefinite period. Gravity springs and deep
groundwater sources may be quite safe without disinfection if the source can be protected against
contamination. This needs to be affirmed during sanitary survey and by chemical analysis of the
water.
In rural areas of South Africa, recent studies have linked some water outbreaks with the
microbiological quality of groundwater, necessitating the need for disinfection (Momba and Kaleni,
2002; Momba et al., 2006). Groundwater with disinfection as the only treatment to eliminate
bacteriological contamination is one of the most common types of water supply for rural
communities. Calcium hypochlorite or bleaching powder is the most appropriate agent, sodium
hypochlorite or liquid chlorine is also used. A free chlorine residual of 0.3 mg/l after 30 minutes
standing time is adequate where turbidity and p+ are low.
2.2.2.3
Treatment of spring water
Springs are commonly found in rolling topography which is incised with water courses, and they
generally occur at the heads of the drainage network. Springs may appear as: seepage springs where
water percolates over a wide area in porous ground, fracture springs issuing from joints or fractures,
or tubular springs where the outflow is more or less like a pipe (Sami and Murray, 1998). The water
from a well-protected spring should all originate from groundwater. Often this will be safe and will
not need any disinfection other than what may be desirable to protect it in a distribution system.
Once the spring water has been channeled into a pipe, a number of chlorination systems may be
appropriate. These will be similar to those used for treating surface water for piped systems. The
discharge of springs may be fairly constant although there may be some gradual seasonal variations
that may require periodic changes in the dosing rate. If the discharge changes rapidly after rain it
may indicate a risk that the spring is being polluted by surface water.
10
2.3
DISINFECTION PRACTICES IN THE PRODUCTION OF POTABLE WATER
Disinfection is the process by which disease-causing pathogens are destroyed. Disinfection also
provides additional protection for any contamination that may occur in the distribution system but
this is dependent on the concentration of residual disinfectant that remains in the system once the
water leaves the treatment plant.
The importance of disinfecting potable water cannot be underestimated. The true value of
disinfection first became evident as early as 1893 when Mills and Reincke, both public health
researchers, after studying a large number of communities, discovered that when a contaminated
water supply was replaced with a purified water source, the general health of the community
improved significantly, far beyond what would be expected by accounting for the reduced incidence
of typhoid and other typical waterborne diseases. In 1903, Allen Hazen, found that when a
community water supply of bad quality was replaced with adequately treated water there was a
reduction in morbidity and mortality due to water borne diseases (White, 1999).
In general microorganisms can be removed, inhibited or killed using either a chemical
disinfection process (e.g. chlorine), a physical disinfection process (e.g. ultra violet radiation) or a
physical removal process (e.g. slow sand filtration). Although the first two methods are commonly
known as disinfection processes, this section also focuses on physical removal processes.
2.3.1
Chemical agents
The most commonly used chemical agents in the water industry are: i) chlorine and chlorine based
compounds which include chlorine gas (Cl2), calcium hypochlorite [Ca(OCl)2], sodium
hypochlorite (NaOCl), chlorine dioxide (ClO2), and mono-chloramines (NH2Cl); ii) ozone (O3), iii)
hydrogen peroxide (H2O2), iv) potassium permanganate (KMnO4), v) iodine (I2) and vi) bromine
(Br2). The commonly used chemical disinfectants in large water works are chlorine gas, chlorine
dioxide, monochloramine and ozone. In small water works chlorine gas, hypochlorites, iodine,
bromine and mixed oxidant gases are typically used as disinfection agents (Van Duuren, 1997).
Chlorine disinfection has been practiced for over a century and has been credited with
saving a significant number of lives worldwide on a daily basis. Although chlorine and chlorine
compounds have been historically the most popular chemical disinfection agents, the special
properties of ozone have caused a rapid increase in its use worldwide (White, 1992). The discussion
in this section will be limited to chemical disinfectants most commonly used in South African small
water treatment plants: chlorine gas, sodium hypochlorite (supplied as a liquid or generated on site
by electrolysis of a salt solution), calcium hypochlorite (usually supplied as granular and commonly
11
known as HTH), chlorine dioxide, chloramines and ozone. A brief review of alternative chemical
disinfectants is also discussed in this section.
2.3.1.1
Chlorine and chlorine based compounds
Chlorine is one of the most effective disinfectants, it is relatively easy to handle, and the capital cost
of chlorine installation is low. It is cost effective, simple to dose, measure and to control, and it has
a relatively good residual effect. Moreover, it reduces many objectionable taste and odour
compounds (chlorine oxidizes many naturally occurring substances such as foul-smelling algae
secretions, sulfides and odours from decaying vegetation), removes chemical compounds that have
unpleasant taste (ammonia and other nitrogenous compounds) and odour (hydrogen sulfide which
has a rotten egg odour) and hinder disinfection (ammonia and other nitrogenous compounds).
Although, there are certainly other disinfectants (such as monochloramine, ozone and ultraviolet)
that are equal to or even better than chlorine (this will be discussed later), chlorine is the most
widely used disinfectant for drinking water in rural developing areas.
Chlorine disinfection is generally carried out using one of the three forms of chlorine
(elemental chlorine (chlorine gas), sodium hypochlorite solution (bleach), and dry calcium
hypochlorite - HTH) or it can be generated on site. The form of chlorine added to water will depend
on the locally available chemicals and equipment. Chlorinating water requires that the operator be
trained in making up the correct solution strengths. He must also ensure that sufficient chemicals
are always available.
On a cost per mass of active chlorine basis, chlorine in the form of a liquefied gas is the
most cost effective option. Using liquefied gas carries the risk of accidental leakage of the gas,
which is why some plants opt for more expensive sodium hypochlorite solution. On-site generated
hypochlorite is well-suited to remote areas close to a cheap source of brine; however an electrical
supply will be required. When chlorine gas is added to water, two species known together as free
chlorine are formed. These species, hypochlorous acid (HOCl, electrically neutral) and hypochlorite
ion (OCl-, electrically negative), behave very differently.
Cl 2(g) H 2 O ‘ HOCl H Cl Hypochlorous acid dissociates (splits up) to form hydrogen and hydrochlorite ions (OCl-)
HOCl ¾ H OCl All of the disinfectant capability of the chlorine gas resides with either the undissociated HOCl or
the OCl- ion – the chloride ion (Cl-) has no ability to kill microbes at the concentrations which occur
12
in drinking water. If either sodium or calcium hypochlorite is used as the source of chlorine, each
will yield OCl- upon dissociation in water.
Hypochlorous acid is not only more reactive than the hypochlorite ion, but it is also a
stronger disinfectant and oxidant. The ratio of hypochlorous acid to hypochlorite ion in water is
determined by the pH. At low pH (higher acidity), hypochlorous acid dominates while at high pH
hypochlorite ion dominates. Thus, the speed and efficacy of chlorine disinfection against pathogens
may be affected by the pH of the water being treated (Chlorine Chemistry Council, 2003).
Fortunately, bacteria and viruses are relatively easy targets for chlorination over a wide pH range.
Furthermore, operators of surface water systems treating raw water contaminated by parasitic
protozoa (e.g. Giardia) may take advantage of the pH-hypochlorous acid relationship and lower the
pH to be more effective against Giardia, which is much more resistant to chlorination than either
viruses or bacteria (Chlorine Chemistry Council, 2003).
Within the permissible pH range of 6.5-9.5, the efficacy of chlorine decreases as the pH
increases. Hypochlorous acid is generally considered to be a destructive, non-selective oxidant,
which reacts with all biological molecules. One of the major disadvantages of chlorine is the
relatively short half life of hypochlorous acid in water which effectively reduces the residual contact
time to 18-24 hours. This has led the industry to rely on the use of chloramines to increase the
lifespan of the combined chlorine residual from 24 hours to 3-7 days.
Although chlorine is the most common disinfectant used for the treatment of drinking water
in South African rural areas, existing chlorine disinfection practices are unreliable and often not
monitored in many of the water treatment plants and small water supply schemes (Pearson and
Idema, 1998; Momba et al., 2004b). Studies (Swartz, 2000; Mackintosh and Colvin, 2002; Momba
and Kaleni, 2002a; Momba et al., 2004a) have shown that the majority of small water works in
South Africa have difficulty providing adequate treatment and disinfection with the result that
consumers are at risk of waterborne diseases even from treated water supplies. Both technical and
human factors have been reported to be the major causes of failure of small rural water treatment
plants to provide potable water to their consumers (Momba et al., 2004b). According to these
authors, chlorine dosing and the delivery of chlorine to the plant remain a major on-going problem
in most of rural water works. A lack of a proper chlorine dosing procedure and monitoring
programme results in insufficient chlorine residuals at the point of treatment. However to have an
effective disinfection, the chlorine dose has to be ratioed to the plant flow rate. In other words,
before applying chlorine to the water, it is important to know the chlorine demand of the water.
A number of countries including South Africa have issued guidance to water suppliers on
disinfectant residual that should be aimed for in distribution. These countries indicate that the
13
residuals should be kept to a minimum consistent with ensuring that microbiological standards are
met and some countries also include to minimize by-products formation, to minimize biofilm
formation and to avoid problems with chlorine tastes and odours and to provide some protection
against re-contamination within the distribution system (Hydes, 1999).
Chlorine demand measurement in small water treatment plants in rural areas is seldom
undertaken by operators. Operators generally use a fixed chlorine dose irrespective of changes in
chlorine demand often leading to overdosing or under-dosing of the chlorine. It has been observed
that the chlorine decay is influenced by the chlorine demand of the water and the reactions with
deposits such as organic and inorganic sediments. It is therefore important for operators to
understand and compensate for the way disinfectant decreases in the distribution system. Although
chlorine is used to reduce bacterial numbers, the mere use of chlorine does not guarantee the
removal microbiological pathogens; it is essential to apply the correct dose at the correct frequency
(Momba and Brouckaert, 2005).
Moreover, any point of chlorine application must be such as to give adequate time of contact
for the chlorine with the water before it leaves the water works. Although the minimum contact
time required is determined by the dosage of chlorine applied, it is desirable to make provision for a
contact time of not less than an hour (Momba and Brouckaert, 2005). A number of different ways of
dosing exist. The following important points must be taken into consideration in designing and
controlling chlorine dosing systems: uninterrupted dosing, uniform distribution to all parts of the
water mass, adjustment of the dosage to the chlorine demand of the water being treated and control
of the dosage to produce safe water without spoiling the taste (Swartz, 2000).
Chlorine gas – Chlorine gas is commonly used on large and medium scale plants. It is supplied as a
liquid in pressurized gas cylinders and is evaporated prior to injection into the water being treated.
Due to the hazardous nature of the gas, appropriate safety measures are required (Voortman and
Reddy, 1997). Therefore gas chlorinators should not be operated and controlled by unskilled
persons who are not fully conversant with the apparatus or dangers of the gas.
Sodium hypochlorite – Sodium hypochlorite is used in many small water treatment plants and is
fed into the system by means of constant head drip feeders or dosing pumps. The constant head drip
feeders have the advantage that they do not require electrical power but one disadvantage is that the
solution can not be introduced into the system under pressure. Storage conditions are important
when using hypochlorite solutions as it decomposes on exposure to heat, light and impurities. The
stock solution should not be stored for more than 1 month, even when sealed and stored under dark
14
and cool conditions. The diluted dosing solution should be prepared in quantities sufficient for 1 to
3 days of operation (Sami and Murray, 1998).
Calcium hypochlorite – Calcium hypochlorite in the form of a dry powder or proprietary tablet-
type dispenser can be used in small water treatment plants. This is more expensive than gaseous
chlorine or hypochlorite solution, but can offer advantages in terms of convenience and low
installation cost. Dosing of the dry granules or powder is not recommended since calcium
hypochlorite is hygroscopic and decomposes in air to form chlorine gas. It can be dosed in the same
way as sodium hypochlorite by dissolving the granules to create solution of appropriate strength.
Granular calcium hypochlorite contains up to 70% chlorine and is more stable, losing only 3-5% of
its chlorine per year, so its dosage is easily regulated (Sami and Murray, 1998). A number of
proprietary in-line and free floating dispensers are available for industrial and swimming pool
chlorination. These devices generally make use of tablets containing mixture of calcium
hypochlorite and calcium carbonate and they function as saturators from which the solution is
gradually released into the line (in-line-dispensers) or surrounding water (free floating dispensers)
(Voortman and Reddy, 1997).
Chloramine – The use of chloramines as a disinfectant is not a new process and has been used for
decades in many cities of developed countries. It has been reported that 20 to 25% of the local
governments within the United States currently use chloramines and the number is expected to grow
due to new regulations (USEPA, 1999). Although chloramines have been used as a disinfectant in
drinking water for many years, their use has not been widespread or highly publicized until
recently.
The process of chloramination has usually been referred to as combined residual
chlorination or the ammonia-chorine process (combination of free chlorine and ammonia). The
process is based upon the reaction of hypochlorous acid with ammonia. There are three types of
chloramine that can be formed by the reaction of chlorine with ammonia depending on the ratio of
free chlorine and ammonia: monochloramine, dichloramine and trichloramine as shown in
Table 2.3.
Dichloramine and trichloramine are less stable than monochloramine and are present only at
low p+ values with high chlorine -to- oxygen ratios. At p+ levels above 8, monochloramine is the
only chloramine of any consequence.
15
TABLE 2.3
CHLORAMINE FORMATION
Chlorine/Ammonia
Reaction
Chloramine species
ratio
5:1
NH3 + HOCl =H2O + NH2Cl
Monochloramine
7:1
NH2 + HOCl =H2O + NHCl2
Dichloramine
9:1
NHCl2 + HOCl =H20 + NCl3
Trichloramine
Chloramines are more commonly used in systems with long retention times as a secondary
disinfectant, especially in high chlorine demand waters where they can provide bactericidal
protection, control of algae, and bacterial after-growth in lieu of free chlorine which would be
exhausted in the extremities of the distribution systems. Advantages of chloramination include the
following:
i)
Chloramines do not react as readily with organic matter in the treated water supplies
thereby dramatically reducing the potential formation of disinfection by-products
(DBPs), such as trihalomethanes (THMs) and halo-acetic acids (HAAs) (USEPA, 1999);
ii)
They are less corrosive (on materials) and have less noticeable taste and odour than free
chlorine (USEPA, 1999).
iii)
Although chloramine treatment may not be effective in all systems, the primary aim of
many utilities in using chloramine as a primary or secondary disinfectant is to reduce the
formation of THMs (Solsona and Pearson, 1995).
However, chloramines are less effective bactericides and virucides than either hypochlorous acid or
hypochlorite ion. Neither enteric viruses nor protozoan cysts are effectively inactivated by
chloramines over a short period of time (10 min) at low dosages. Chloramines when improperly
applied can lead to nitrification problems in distribution systems (American Water Works
Association, 1982).
The cost of using chloramines for disinfection is about the same as the cost for chlorine. The
use of chloramines is 20% less expensive than alternative methods of treatment. Monochloramine
for water disinfection is a safe and proven method when used as a secondary disinfectant. It
provides adequate disinfectant residual that will enable compliance with bacteriological water
quality standards (Momba and Binda, 2002b; Momba et al., 2003).
16
Chlorine dioxide – Chlorine dioxide is a disinfectant now being used fairly extensively throughout
the world, but particularly in Europe and United States (Solsona and Pearson, 1995). It has been
used in South Africa for the disinfection of mine service water where ammonia levels are high and
for drinking water treatment where algal problems occur. It has also been used experimentally
where iron and manganese problems occur. Its major advantages over the use of chlorine include
the following: i) generally more powerful bactericide, sporicide and virucide; ii) does no react with
ammonia or aromatic organics is capable of destroying certain precursors of THMS; iii) in general
produces less taste and odours, and more effectively oxidises organic tastes and odours; iv) the
residual in the distribution system is better maintained than with free chlorine; v) chlorine dioxide is
not as affected by variations in p+ as is chlorine and vi) it is more effective for the removal of iron
and manganese.
Chlorine dioxide is an unstable gas and must be generated on site. It can be produced from
sodium chlorite in combination with chlorine and / or a strong acid (HCl or H2SO4). The production
process must be carefully monitored and controlled to produce high levels of chlorine dioxide.
Hence, although used extensively in other countries, chlorine dioxide does present a number of
limitations for its use in small water systems and these include the following: i) high cost of
precursor (NaCl2); ii) sensitive to light and hence should not be used where water is contained in
open tanks; iii) the by-products of chlorine dioxide disinfection include chlorite and chlorate which
may have health implications for consumers.
2.3.1.2 Ozone
Ozone is a naturally occurring form of activated oxygen produced during lightning storm discharges
and is continuously occurring in the stratosphere by ultraviolet action. Ozone can also be artificially
produced by the action of high voltage discharge in the presence of air or pure oxygen (O2). Due to
the fact that the gas breaks down rapidly, users must generate the gas on site.
Ozone is a powerful oxidant and disinfectant, with thermodynamic oxidation potential
that is the highest of all common oxidants. High oxidation potential of ozone increases its reactivity
with other elements and compounds and the better high kill rates of fungus, bacteria, parasites (i.e.
Giardia and Cryptosporidium) and viruses are achieved. Control of more resistant cysts can be
achieved at 10 mg/l (Laughton et al., 2001). It is well known that the addition of a strong oxidant
such as ozone to humic waters reduces the colour significantly.
Ozone treatment is reported to have no harmful residuals that would need to be removed after
treatment. The most important disadvantage of the ozone disinfection is the lack of a residual
17
disinfectant that will need to protect the treated water against the bacterial regrowth or afterregrowth (Momba et al., 1998). Consequently, a secondary disinfectant will always be required to
provide a residual.
The perception that ozone is a more expensive treatment is one apparent reason for it not
being more commonly used in the developing countries especially in small water treatment plants.
Also, widespread availability and distribution of information or publicity on ozone treatment has
been very lacking in the developing countries (Eagleton, 1999).
2.3.1.3
Use of alternative chemical disinfectants
Every water treatment process has limitations and requires specific operation, maintenance and
replacement of critical components, in accordance with manufacturer’s recommendations. To meet
growing public demand for safe and clean potable water, many water utilities are exploring the use
of alternative disinfection methods, which will correspond to the requirement of each and every
water treatment plant. To meet this requirement, a disinfection technology which has the following
characteristics should be employed: i) it should be affordable, ii) it should be simple yet give
accurate doses, iii) it should be simple to operate and maintain, iv) any materials or chemicals which
are required for operation should be readily available at close proximity to the place of usage. This
section deals with the use of alternative chemical disinfectants that are currently employed in
industrialized countries in some of the small and large water treatment plants: bromine disinfection,
hydrogen peroxide disinfection and potassium permanganate disinfection.
Bromine – Like chlorine, bromine is a halogen and acts in much the same way as chlorine. It can be
supplied either as liquid bromine (but is highly corrosive), as bromine chloride (less corrosive) in a
slow releasing organic complex (easy to handle but costly), or as NaBr salt which must then be
oxidized to bromine on site (e.g. by addition to a chlorine solution) (Solsona and Pearson, 1995).
Bromine has a number of advantages which make it a suitable disinfectant under specific
conditions. These include the following: i) more reactive than chlorine for inactivating enteric
viruses; ii) bromamines \which form when ammonia is present are significantly more effective than
chloramines; iii) the disinfection effectiveness of bromine is not so dependant on p+ as for chlorine;
iv) bromine and bromamines are less stable than their chlorine equivalents; v) being a liquid at
ambient temperatures, bromine is less volatile than chlorine, and hence can be stored and handled
more easily than chlorine gas. However, the disadvantages are its low oxidation ability, its higher
price than chlorine and the caustic effect of the elementary bromine.
18
Hydrogen peroxide – Hydrogen peroxide is a weak acid, clear colourless liquid, miscible with
water in all proportions. It is a physiological compound, which forms two stable and toxicological
inert decomposition products (water and oxygen) (Solsona and Pearson, 1995). It is commercially
available in aqueous solutions over a wide concentration range. Although it is a strong oxidant, it is
proven a poor disinfectant. Hydrogen peroxide can be used to disinfect drinking water at a
maximum dosage of 17 mg/l (100% hydrogen peroxide) and the residual in the consumable water
must be lower than 5 mg/l (100% hydrogen peroxide) (Momba, 1997). To achieve adequate
disinfection, higher dosages are required as compared to chlorine (15 000 to 50 000 mg/l for H2O2
vs 0.5 to 2 mg/l for chlorine), with extended contact times (Momba, 1997). In comparison to
chlorine, the cost of the hydrogen peroxide product is higher (up to 8 times more costly than
chlorine for the same dose), and the availability at more remote areas is very poor. The
measurement of a residual for monitoring purposes is also very difficult. Advantages of hydrogen
peroxide for use in small water systems include: i) ability to store large quantities under minimal
storage regulations; ii) not hazardous to the environment and iii) effective over a wide p+ range.
In general hydrogen peroxide is unsuitable as a drinking water disinfectant even in the
developed world and could be considered for drinking water when used in conjunction with another
oxidant or catalyst. Like monochloramine, hydrogen peroxide is better at attaining and maintaining
a disinfectant residual than chlorine and ozone (Momba, 1997). Hydrogen peroxide has not been
applied in South Africa to any extent to date for disinfection of drinking water.
Potassium permanganate – Potassium permanganate is primarily used as an oxidant in water
treatment processes, and not as a disinfectant. As an oxidizing agent, potassium permanganate is
effective in controlling tastes and odours, as well as at removing hydrogen sulfide, iron and
manganese. It has been used in South Africa as an oxidant for the removal of iron and manganese
at certain water treatment plants (Solsona and Pearson, 1995). It is also not readily available in the
remote areas. Although it does demonstrate some disinfection properties, the die-off rates are lower
than for chlorine.
Potassium permanganate decomposes to manganese dioxide, which is a precipitate which
can cause colouring of washing, household utensils etc., and hence potassium permanganate is
usually added before the coagulation/ flocculation step in water treatment (Solsona and Pearson,
1995). The primary disadvantages to its use as a disinfectant in small water systems are its high
cost, and resulting residual which gives rise to discolourisation of washing, etc., unless removed in
a coagulation/flocculation step.
19
2.3.2
Physical agents (Ultraviolet irradiation)
Physical agents include heating (boiling) and irradiation. Boiling is practical only in small-scale
applications; however the major disadvantage is the high energy cost of boiling water, especially
where wood is the source of energy as well as the risk of scalding of children who handle the boiled
water. Ultraviolet irradiation (UV) as a disinfection method is gaining popularity in the potable
water industry (Momba et al., 1996). This section focuses only on UV disinfection process.
Ultraviolet irradiation – Ultraviolet irradiation is a relatively old technology which was first used
for disinfection purposes in 1910 and is becoming a common technique for disinfecting drinking
water. The ability of UV to treat unfiltered water is dependent on water clarity and turbidity. Since
most waters contain large amounts of inorganic and organic particles, which will decrease the
effectiveness of the UV treatment, it is recommended that some type of filtration in addition to UV
treatment be used to remove larger organisms and solid matter from the flowing water (Momba et
al.,1998). To achieve the killing rate of a combined filtered/UV unit, an unfiltered/UV unit must
expend more energy to be as effective. It has been recommended that a filter between 25-50 µm is
ideal for removing sediment, and organisms larger than bacteria and viruses (Momba, 1997).
The benefits of this technique in drinking water treatment include the following: i) UV does
not alter taste, odour, colour or pH of the water; ii) no need to add chemicals in water and no
formation of disinfection by-products; iii) UV systems are compact and easy to install; iv) they
require very little maintenance and are cost effective (cost depends on the amount of water to be
treated, pumping, pre-filtration and UV dose); v) the most important benefit in terms of disinfection
is the ability of UV to inactivate Cryptosporidium oocysts which are generally resistant to most of
the other chemical disinfectants.
Ultraviolet treatment works to achieve disinfection efficiency by exposing target organisms
to ultraviolet light (UV) energy waves. The exposure time and the intensity of the UV light
application would determine the effectiveness of a lethal dose. In addition, the system performances
would not only be affected by the dose and flow rate but also by the water quality of the water being
treated. Ultraviolet absorbing constituents in water, such as organics, turbidity, and color, can
influence the effectiveness of the system. As UV transmission decreases, additional UV energy
would be required to maintain peak effectiveness. Typical maintenance procedures to maintain peak
effectiveness in these systems include cleaning the quartz sleeves, replacing lamps, and checking
proper function of the power module, inspecting the overall structural integrity of the system which
includes a pretreatment unit. Training required for these procedures would be minimal.
Although UV irradiation is a good disinfection process for killing parasites and other
20
organisms that are resistant to chlorination, like ozone, it has no residual protection that will be
needed in treated water during distribution, and this means that the final water is at a high risk of
being re-contaminated during storage. This technology is therefore good for point-source use, but
not for developing communities.
2.3.3
Physical processes
Physical processes include gravity separation and filtration. While gravity separation concerns
mostly sedimentation and flotation, filtration processes include mechanical straining, absorption
and adsorption, and, particularly in slow sand filters and biochemical processes. These processes
play a very important role in removing viruses (White, 1992), schistosomes (bilharziasis)
(Cairncross and Feachem, 1983) and protozoa cysts (Van Duuren, 1997). The removal of
microorganisms, especially protozoan is very dependent upon the state and operation of sand filters.
In other words, depending on the size, type and depth of the filter media and the flow rate and
physical characteristics of the raw water, filters can remove suspended solids, pathogens and certain
chemicals, tastes and odours. Straining and settlement are treatment methods that usually precede
filtration to reduce the amount of suspended solids that enter the filtration stage (CDC, 2002).
The size of microbes and other colloidal particles is of utmost importance when using
filtration as a means of water purification. Viruses are the smallest of waterborne microbes, with a
size of 20 to about 100 nanometers (nm). These viruses are the most difficult to remove by
filtration. Bacteria are larger than viruses, being about 500 to 3000 nm in size. Bacteria are still too
small to be removed from water by sedimentation or settling (WHO, 2002b). Although these
microbes are too small to settle out, they often clump together with other particles, thereby
increasing the size. This increases the efficiency of the filtration methods. A 95% to 100%
reduction of faecal coliforms can be expected in water that has been filtered through slow sand
filtration while rapid sand filters are capable of reducing turbidities and enteric bacteria by as much
as 90%. Enteric viruses are not effectively removed by this method. To increase the reduction of
viruses and bacteria using this method, coal can be added to the sand. Then positively-charged
salts, such as alum, iron or manganese are added. This media then can reduce bacteria and viruses
by up to 99% (WHO, 2002c).
Membrane processes – Membrane processes offer an attractive alternative for primary disinfection
of water. Disinfection is achieved by removal of the viruses and bacteria from the water system.
One of the key aspects related to water treatment equipment performance verification is the range of
21
feedwater quality that can be treated successfully, resulting in treated water quality that meets
drinking water quality standards. The influence of feedwater quality on the quality of treated water
produced by the equipment should always be considered.
The ultra-filtration membrane was
designed to withstand feedwater turbidity of less than 20 NTU, but it should preferably be used or
operated below 10 NTU (Pillay and Jacobs, 2004).
Membrane systems have small land requirements, use fewer chemicals, and are not as
complicated as conventional treatment systems. However, a secondary disinfectant will always be
required to provide a residual which is indispensable to protect final water against re-contamination.
A number of different types of membranes are available and are generally classified by the pore size
as indicated in Table 2.4. Typical membranes processes are: microfiltration, ultrafiltration
nanofiltration and reverse osmosis. Hence appropriate selection of a membrane will ensure the
removal of the target organism thus ensuring efficient disinfection. The removal of much smaller
viruses seems to be possible with these membranes as well since most of the viruses are attached to
larger bacteria or other particles.
The advantages of membrane processes are that there is no need for chemicals, and water
clarification can take place simultaneously. However, membranes do become clogged with time
despite the ongoing cross-flow cleaning process. Hence pre-treatment of the water by conventional
means is advocated to lengthen the life of the costly membranes. Capital costs are high and
operation is complex, requiring a high level of skills. Future developments may enable this to be
considered as appropriate in the future. In South Africa microfiltration has not been used
specifically for disinfection, but has been applied with some success to the concentration of water
treatment sludge. Because of the cost of the membrane units when compared to other techniques
such as chlorination that is commonly used in the water treatment field, Government has been
adamant about subsidizing the unit. It is important for the Government to positively consider
installing such membrane facilities that can produce water of high quality in order to counteract the
enormous negative consequences that could arise from the consumption of poorly treated drinking
water (Pillay and Jacobs, 2004).
22
TABLE 2.4
MEMBRANE PROCESS CLASSIFICATION
Membrane Process
Membrane Pore Size (nm)
Microfiltration
77.5 to 550
Ultrafiltration
3.25 to 325
Nanofiltration
1 to 32.5
Reverse Osmosis
0.1 to 5.5
Note: Virus size 20-100 nm and bacteria 500 to 3000 nm
2.4
WATER DISTRIBUTION AND STORAGE
The water distribution system comprises the network of pipes that transports water to the
consumers. The size and distance of a water distribution system depends on the area it serves, the
size of the population and the distance from its source. The main objective of the distribution is to
supply the community with potable water as well as to ensure sanitary conditions. Assuring that
drinking water remains safe after leaving a water treatment facility to the point of delivery to
consumers is still a major challenge for drinking water providers. For most water systems, there is a
larger investment in the infrastructure and operations of water delivery than water treatment, yet the
vulnerability of water distribution is often overlooked.
There is increasing evidence that finished water may undergo substantial changes in quality
while being transported through the distribution system to the consumer. The distribution system is
thus the final barrier in preventing waterborne disease outbreaks on one hand and may contribute to
water quality deterioration on the other (Momba et al., 1998; Momba and Binda, 2002). It is
believed that many of the waterborne disease outbreak problems associated with cholera were
related to improperly operated and poorly maintained distribution systems (Clark et al., 1993).
Among 619 waterborne diseases (chemical and microbial) outbreaks reported in the U.S. for public
water systems, from 1971 to 1998, 113 (18%), were caused by distribution system deficiencies.
Cross connections or back siphonage, corrosion or leaching of metals, broken or leaking water
mains, contamination during storage, contamination of mains or repair, contamination of household
plumbing or inadequate separation of water mains and sewers have been reported to be distribution
system failures (Craun and Calderon, 2001). Among the outbreaks caused by distribution system
failures, 66% have been reported to involve microbial pathogens (Craun and Calderon, 2001).
23
Fortunately, the importance of maintaining water quality during distribution has received
growing attention in research and practice over the past decade. One specific matter of distribution
water quality that deserves mention, concerns the maintenance of a disinfectant residual throughout
the distribution system (Hrudey and Hrudey, 2004). The disinfectant residual is designed as a
measure of protection against harmful microbes encountered after water leaves the treatment
facility. This has been a requirement in a number of jurisdictions where chlorination has been most
common. In the intrusion of pathogens resulting for example from a broken water main, the level of
the average chlorine residual will be insufficient to disinfect contaminated water. In such cases, it is
the monitoring of the sudden drop in the chlorine residual that provides the critical indication to
water system operators that there is a source of contamination in the system (Chlorine Chemistry
Council, 2003).
Drinking water in storage tanks can be easily contaminated if storage tanks are not properly
closed. Often if the tanks are underground, possibly in close proximity to sewage, cross
contamination due to sewage overflow may occur. It is therefore recommended that reservoirs for
storage of potable water be situated and built in such a way as to lower the risk of sewage or any
other contaminants from being introduced into the water distribution system (Momba, 1997). It is
important to note that the proper maintenance and operation of water supply, treatment and
distribution systems are essential parts of any effort to ensure the on-going production and delivery
of the highest quality drinking water possible (Momba et al., 2004b).
2.5.
MICROBIOLOGICAL QUALITY OF THE FINAL WATER & PUBLIC HEALTH
SIGNIFICANCE
Lack of access to adequate drinking water supply is largely responsible for more than 1 billion
estimated of diarrhoeal diseases and 2.2 million associated deaths worldwide (WHO, 2001; Gleick,
2002). The vast majority of people lacking access to safe water reside in developing nations (UN
World Water Assessment Program, 2003). This implies that many people in the developing world
still depend on contaminated water sources for their daily water needs. This is therefore a challenge
to the water industry to provide clean and safe drinking water to their consumers. Drinking water
quality can be assessed in terms of the senses (smell, taste, colour), physico-chemical and
microbiological properties, both quantitatively and qualitatively. This section discusses the
monitoring strategy used in South Africa to assess the safety or the quality of drinking water at the
plant and in the distribution system, and the public health significance associated with the
24
microbiological quality of water supplied by small water treatment plants.
2.5.1
Monitoring the safety of water supplies
In South Africa, the South Africa National Standard (SANS 241, 2005) is used as the official
specification for assessing the quality of drinking water. Moreover, the Water Quality Guidelines
for Domestic Use published by DWAF in 1996 provide a comprehensive discussion of all quality
aspects relevant to water for domestic use with recommended quality ranges for different situations.
The Assessment Guide published by DWAF, the WRC and the Department of Health in 1998 also
gives a user-friendly presentation of the assessment procedure for drinking water. Consequently, the
safety of treated water used for domestic purpose is assessed according to the lists of quality
criteria, standards and guidelines stipulated in the above official guide documents.
In order to ensure that drinking water is microbiologically safe to drink, there must be no
pathogens in the water. The detection of waterborne and water-related pathogens requires
expensive, complex, and time consuming techniques, while others are not detectable by
conventional methods at all. Water quality monitoring programs are, therefore, usually based on the
test of indicator microorganisms. These organisms, such as certain coliform groups, occur in the
intestine of humans and are easy to detect. Their presence in treated water is therefore taken as an
indication that drinking water was not adequately treated or disinfected. An ideal indicator
microorganism should fulfill the following criteria: i) it should always be present when the
pathogen is present and should be absent in clean, uncontaminated water; ii) it should be present in
numbers greater than the pathogen it indicates; iii) its survival to the environment and resistance to
the treatment processes should be comparable to that of pathogens; iv) it should not be harmful to
human health; v) it should be easy to identify and to isolate and vi) it should be suitable in all types
of water (Grabow, 1996). This section only discusses groups of indicator organisms recommended
by SANS (241, 2005) to assess the effectiveness of disinfection.
Total coliforms – Total coliforms are a group of bacteria that are commonly used to monitor the
microbiological quality of drinking water as they satisfy many of the ideal characteristics of an ideal
indicator organism. They are used to assess the effectiveness of the disinfection process and the
integrity of the distribution system. It is generally assumed that water that is free of coliforms
should have no pathogens present, however it should be remembered that the coliform bacteria are
only used as an indicator of the possible presence of pathogens, and detailed analysis for the
presence of pathogens is required when coliforms are detected.
25
Faecal coliforms and E. coli – Faecal coliform and E. coli are subgroups of the total coliforms that
are typically present in contaminated water. SANS 241 (2005) recommend that the water industry
uses E. coli as the preferred indicator organism for possible presence of faecal pollution and to
ensure that the objectives of disinfection have been achieved.
2.5.2
Quality at water works and in distribution systems
Three basic mechanisms govern the occurrence of pathogenic microorganisms in treated drinking
water: i) the microbes break through the treatment process from the source water supply, ii) the
microbes regrow from very low levels, typically in biofilms, and iii) the organisms result from a
recontamination of the treated water within the distribution pipeline system. These mechanisms are
incorporated in the multiple-barrier concept for water treatment as described earlier in this chapter.
The discussion here will focus on the effect of the inadequate treatment on the quality of the treated
water.
Multiplication of bacteria in drinking water during distribution is usually referred to as
regrowth. This term implicates the microbial growth process in the phenomenon of increased
microbial cell numbers. Regrowth of coliform bacteria in distribution systems has been reported as
a major problem for a number of water utilities (LeChevallier et al., 1991; Momba et al., 1998).
High levels of bacteria in small water distribution systems could also be related to the inefficiency
of the initial treatment barriers. The failure of rural schemes in South Africa to provide potable
water to consumers has been a matter of concerns. Conventional water treatment processes could be
capable of reducing the number of indicator microorganisms if they are well applied. However, it
has been noted that low or high doses of coagulants could produce high turbidity in water. High
turbidity increases the potential for the transmission of infectious disease due to shielding of the
bacteria within the particulate matter (Momba et al., 2004a).
Moreover, most finished waters in rural developing areas are characterized by the absence of
chlorine residual throughout the distribution system, which leads to total and faecal coliform counts
equal to that of raw water before treatment (Swartz, 2000; Mackintosh and Colvin, 2002; Momba et
al., 2004, a; b). It is important that small water treatment plants maintain adequate concentrations of
chlorine to prevent regrowth and repair of bacteria.
2.5.3
Impact of microbiological quality of treated water on public health
Diarrhoeal diseases attributed to poor water supply, sanitation and hygiene account for 1.73 million
deaths each year and contribute over 54 million disability adjusted life years, a total equivalent to
26
37% of the global burden of disease (WHO, 2002). Diarrhoeal diseases are therefore considered as
the 6th highest burden of disease on a global scale, a health burden that is largely preventable
(WHO, 2002).
A significant portion of residents in rural communities of South Africa are exposed to
waterborne diseases and their complications (Obi et al., 2002). The impact of poor water quality on
human health is shown in Table 2.5. Cholera, typhoid fever, salmonellosis, shigellosis,
gastroenteritis and hepatitis outbreaks have been linked to contaminated drinking water (Grabow,
1996). Between 1980 and 1989, approximately 25 251 cases of cholera were reported in KwaZuluNatal, and 845 cases in Eastern Cape of South Africa (Department of Water Affairs and Forestry,
2002). Most severely affected community were people in rural areas living in conditions of poverty,
poor sanitation and poor domestic supply.
Typhoid fever, salmonellosis and shigellosis are enteric disease commonly transmitted by
drinking water. Areas affected by typhoid fever are Mpumalanga, Eastern Cape and KwaZuluNatal. These provinces are regarded as very poor with domestic water supply and poor sanitation
facilities (Department of National Health and Population Development, 2001).
Heterotrophic bacteria have been isolated from the in-plant reservoirs and distribution
systems, these include Flavobacterium species (responsible for neonatal meningitis, meningitis in
adults and respiratory tract infections), Enterobacter cloacae (opportunistic pathogen isolated from
urine, sputum, pus, and spinal fluids is responsible for urinary tract, lower respiratory tract and bone
joint infections) and Pseudomonas aeroginosa (causes eye and ear infections and also infections of
wounds and burns) (Momba and Kaleni, 2002; Momba et al.,2004; 2005).
TABLE 2.5
IMPACT OF POOR WATER QUALITY ON HUMAN HEALTH (2001-2005)
Waterborne diseases
No of reported cases
Average number of deaths
Cholera
667 300
92 000
Typhoid Fever
151 000
6 000
Paratyphoid Fever
35 000
2 000
Hepatitis A virus
112 000
1 000
Source: Department of Health, 2006
In addition, the coccodian genus Cryptosporidium is increasingly recognized as an important agent
of gastrointestinal disease. Infection with this protozoan parasite can lead to chronic, life27
threatening conditions in immunocompromised individuals and to acute gastroenteritis in healthy
people. Taking into account the impact of drinking water of low microbiological quality on the
health of rural communities, it is important for local water authorities to develop strategies leading
to safe drinking water.
2.6
IMPROVING DISINFECTION EFFICIENCY IN SMALL WATER
TREATMENT PLANTS
To develop a health protection strategy, it is vital that all the factors that indicate the quality of
water supply service should be reported including monitoring the efficiency of treatment plant for
indicators of pollution. The principal objective of drinking water quality surveillance is to reduce
the risk of water related diseases by developing and implementing cost-effective surveillance that
will identify and facilitate the elimination of the sources of contamination of water supply.
Water quality surveillance has been defined as the continuous and vigilant public health
assessment and overseeing of the safety and acceptability of drinking water supplies. The
surveillance solutions to disinfection problems include source water selection and basic monitoring,
bacteriological and chemical analysis. Remedial action strategies should be formulated and also
routine-monitoring programs should be established. The selection of water sources, the use of
alternative disinfectants as an upgrading strategy, process optimization as a remedial strategy and
the education of local water authorities are discussed in this chapter. In addition, hygiene and
education of rural community are highlighted.
2.6.1
In-service training of water personnel and management
The greatest protection that consumers can achieve from dangers posed by contaminated water is to
be assured that the operators of their drinking water system know and fully understand the system,
its capabilities and its limitations. No amount of regulation or stringency in drinking water quality
criteria will serve consumers better than having drinking water providers well-trained with the
ability to learn effectively from their mistakes, external challenges and previous water quality so
that future problems can be avoided or minimized. Ultimately, drinking water providers must accept
that providing a technologically challenging undertaking continues to grow in its sophistication.
These are characteristics of knowledge based industry. Consumers would not tolerate having their
telephone system or home computer serviced by inadequately trained personnel. This concept could
28
also be applied to water industry. Water safety thus is highly dependent on the actions of the
operators who have their hands on the control panels.
Smith (1995) observed in a critique of the parties involved in the Milwaukee outbreak that
some states in the U.S. have more rigorous training requirements for hairdressers than they do for
water treatment operators. The article emphasizes the point that water treatment operators should be
seen as holding a responsibility for public health at least as vital as any other health professional.
Likewise, the provision of safe drinking water demands technologically and scientifically
sophisticated management and leadership. Water authorities driven strictly by their economic
bottom line, without regard to their scientific competence, sooner or later invite serious water
failures. Therefore, to assure that effective performance is achieved, responsibility and
accountability must be established at all levels within the organization of a drinking water provider
(Hrudey and Hrudey, 2004).
2.6.2
Hygiene education and community based management
Water and sanitation programs will not lead to improvements in health unless they are accompanied
by effectively designed programs of health education which promote: i) community participation on
decisions involved in the installation of water supply schemes; ii) encouragement of the appropriate
use, transport and storage of water, iii) maintenance of water supply programs; iv) encouragement
of the construction, use and maintenance of latrines, v) hygiene education programs directed at
washing hands, preparation of weaning foods and disposal of children’s faeces.
Hygiene is the maintenance of health standards. Hygiene education comprises a broad range
of activities, aimed at changing attitudes and behaviours, to break the chain of disease transmission
associated with inadequate water and sanitation. In rural areas, communities are situated far from
the water supply distribution points. They thus store water in containers for long periods of time and
this increases the probability of contamination (Momba and Kaleni, 2002; Momba and Notshe,
2002). Hygiene education informs the rural community about the correct use, storage and disposal
of water.
In most parts of rural South Africa the following problems are common: i) information is
not readily available, ii) literacy levels are low, iii) there is a lack of scientific understanding of the
implications of poor water quality, iv) there is a lack of public and political support for education,
v) severe economic constraints are prevalent, vi) policies and instrument are out-dated, vii)
institutional arrangements are poor (Mtetwa and Schutte, 2002). The above factors thus present a
major challenge to the efficient management of rural water supply. It calls for new approaches that
29
are relevant, effective and that will increase sustainability and effective decision making in datapoor environments.
In South Africa it is essential to understand the attitudes and behaviors of developing
communities towards water and sanitation. Most rural communities rely on government to make
sure that their projects are sustainable, but it is necessary for them to contribute themselves towards
sustainability of their projects, as well as the development of appropriate hygiene education
awareness programs.
Community involvement is important in the management of water supply to ensure that: i)
local leadership is representative and accountable, ii) the technology of choice is supported by the
community, iii) all community members understand their tariffs and operation and maintenance
(O&M), iv) the best people are selected for operation, management & training. Community based
organizations are encouraged to be involved in the management of their water supply systems
which should include the management of the water quality aspects.
Community based organization management systems have been implemented in many
countries such as Uganda and the United States of America (Bwengye, 2002) Similar systems have
been encouraged in South Africa with community based organizations such as Mvula Trust situated
in KwaZulu-Natal province (Vermeulen, 2002). It is therefore important for rural communities and
local municipality to work together with local water authorities on infrastructure design and
management system to ensure that improved water and sanitation services meet people’s needs and
that they are sustained.
The following chapter focuses on the survey of disinfection efficiency of rural small
drinking water treatment plants in South Africa.
30
CHAPTER III
SURVEY OF DISINFECTION EFFICIENCY OF SMALL DRINKING
WATER TREATMENT PLANTS
In an endeavour to collect sufficient data to formulate guidelines on improving the efficiency of
disinfection of small water treatment plants in South Africa, a detailed survey of 181 small water
treatment plants across seven provinces was conducted. The seven provinces were selected on the
basis of familiarity with the areas, economic status, and rural areas experiencing technical and
management problems. Information gathered included various methods of disinfection, equipment
currently employed, performance of the treatment plants, knowledge and skills of the operators as
well as other technical and management issues.
3.1
SURVEY AREA
To ensure a comprehensive coverage of the country, small water treatment plants mainly located in
rural communities of the following provinces were surveyed: Limpopo, Mpumalanga, North-West,
Free State, KwaZulu-Natal, Eastern Cape and Western Cape. The geographic position system
(GPS) co-ordinates of each site were logged during the survey to facilitate future incorporation into
a geographical information system (GIS) that is being developed for the country.
3.2
SURVEY METHODOLOGY
A questionnaire (Appendix 3.1) was designed to obtain the required information such as: the
ownership and design capacity of each water treatment plant, the type of raw water sources and
related characteristics, the pre-disinfection and disinfection processes, the state of the equipment
and other technical and management issues. To achieve these, on-site visits of small water
treatments plants in the designated provinces were conducted from June 2004 to December 2005.
Wherever possible, some plants were visited at least twice during the study period.
Microbiological and physico-chemical analyses of water samples collected from the raw
water and final water at the point of treatment and at the point of consumption were performed
using standard methods (APHA, 1998). Briefly, the chlorine residual concentrations, pH,
temperature, turbidity and the conductivity of water samples were measured on-site using a multi31
parameter ion specific meter (Hanna-BDH laboratory Supplies) thermometer, microprocessor
turbidity meter (Hanna instruments) and conductivity meter (Hanna instruments) respectively. Total
and faecal coliforms were used to monitor bacteriological quality as stated in the South African
Water Quality Guidelines for Domestic Use (DWAF, 1996) and SANS 241 (2005).
3.3
RESULTS OF THE SURVEY AND DISCUSSION
3.3.1
Small water treatment plant ownership
Figure 3.1 illustrates the percentage and categories of plant ownerships in various provinces during
the study period. Four categories of ownership were identified viz Local Municipality, Department
of Water Affairs and Forestry (DWAF), Department of Health (DOH) and Water Board (private
company).
In Mpumalanga, the Local Municipalities were the major owners with the exception of the
water treatment plant of Nelspruit that is now owned by Biwaters, which is a private company. In
Limpopo, plant ownership was divided between the Local Municipalities and DWAF. In NorthWest, the ownership of the plants was distributed into two categories viz Local Municipalities and
Water Boards (Botshelo Water and Magalies Water). Sixty seven percent of the plants were owned
by Local Municipalities while Botshelo and Magalies Water Boards owned 22% and 11% of the
plants respectively. Five (Taung, Wolmaranstad, Kudumane, Stella, Vryburg) of the towns in the
Province were supplied by Sedibeng’s water treatment plant, which was situated in the Free State
Province. Eighty six percent of small water treatment plants were owned by District Municipalities
in the KwaZulu-Natal province. In the Eastern Cape Province, 88% of plants were owned by the
District Municipalities with the remainder distributed amongst the Department of Water Affairs and
Forestry, the Department of Health and a private company (Water and Sanitation Services of South
Africa - WSSA) which managed the plants on behalf of the District Municipality. All the plants
surveyed in the Free State Province and in the Western Cape Province were owned by the District
Municipalities. Overall 81% of the small water treatments surveyed in South Africa were owned by
the District Municipalities (Fig. 3.1).
3.3.2
Design capacity of small water treatment plants
Small water treatment plants in rural areas are generally classified as plants having a maximum
capacity of 2.5 Ml/d although plants of up to 25 Ml/d may sometimes also fall into this category.
The survey did not limit itself to this classification as some of the plants supplying water to rural
areas were found to exceed this capacity. The capacity of the plants surveyed during the
investigation varied between 0.3 Ml/d and 120 Ml/d. Most plants were operating below the design
32
capacity. Some of the plants visited were in the process of being upgraded or had recently
completed upgrades.
In Mpumalanga, small water treatment plants situated in peri-urban regions usually provide
water to the towns, townships as well as to some villages. Package plants were observed to be rare
and few cases were recorded. The largest plant visited in Mpumalanga was Witbank with a design
capacity of about 120 Ml/day. Most of the plants had a capacity of more than 1 Ml/day. Some plants
were in the process of being upgraded or had recently been upgraded. However in Limpopo, most
of the plants were package plants with a capacity of less than 1 Ml/day. The largest plant was found
in Mhinga with a design capacity of 37 Ml/day.
In the North-West Province, the design capacities of the plants ranged between 1.3 and
60 Ml/d. The Mafikeng water treatment plant was the largest plant and has a design capacity of
60 Ml/day. The majority of the plants were operating below the design capacity. The capacity of
the plants investigated in the Free State Province ranged between 0.5 Ml/d and 11.5 Ml/d. The
largest plant was at Parys with a capacity of 11.5 Mld. The capacity of the plants was determined by
the capacity of the clarifiers (up-flow velocity of 1 m/h) and the rapid gravity sand filters (flow rate
of 5 m/h) as the flow meters at 7 of the 13 plants investigated were inoperative. The plant with the
lowest capacity (Oranjeville) was in the process of being upgraded.
In KwaZulu-Natal, the design capacities of the plants visited ranged from small waterworks
with capacities of 100 m3/d (Manjokeni waterworks situated near Bergville) to largest capacity
plant of 32 Ml/d (Ezakheni Waterworks in Estcourt. Due to the lack of plant records and flowmeters
in most plants especially in rural and peri-urban areas, the design capacities were assessed based on
the dimensions of the unit operations.
In the Eastern Cape, the Umtata plant was the largest waterworks visited during the survey
period, with a design capacity of 60 Ml/d; however, most of other plants were designed for more
than 1 Ml/d. Most of these plants were operating below design capacity. Nearly half of the plants
were undergoing some sort of upgrading or had recently completed the upgrading.
In the Western Cape, the design capacities of the plants visited ranged between 1 and
60 Ml/d. The largest plant visited was George water treatment plant with a design capacity of
60 Ml/d. While 62% of the plants were designed for less than 10 Ml/d, 38% of the plants had the
design capacity ranging between 11 and 30 Ml/d. The majority of the plants were operating below
the design capacity. The Sandhoogte plant was the only plant that was undergoing upgrade.
33
Municipality
DWAF
No of Plants Surveyed
Private
200
181
100
180
160
80
140
120
%
60
100
80
40
60
54
36
20
N S
o u
r
o v
f e
y
P e
l d
a
n
t
s
40
19
28
18
20
13
13
R SA
W estern Cape
Eastern Cape
KwaZulu Natal
Free State
North W est
M pum alanga
0
Lim popo
0
Fig. 3.1 Category of Ownership of Small Treatment Plants surveyed in South Africa
3.3.3 Type of raw water sources
Figure 3.8 illustrates the types of raw water sources used by small water treatment plants in the
designated provinces. Appendix 3.2 gives full details on the type of water sources used as intake
raw water by each plant visited in various provinces. This information can also be found in the
Database.
Overall 86% of the small water treatment plants surveyed in South Africa abstracted their
raw water from surface water, although 10% of the plants used groundwater or a combination of
both water sources (4%). In Mpumalanga, only 5% of the waterworks surveyed abstracted intake
water from groundwater. In Limpopo, 6% of the plants abstracted intake water from groundwater
and 3% used a combination of both surface and ground water sources. The North-West province
had the highest usage of groundwater (24%). A few of the plants draw water from unprotected
springs. The surface water in the province was generally characterized by high turbidity and some
of the dams were highly polluted with algae. In the Western Cape, the majority of the plants were
designed for the removal of colour, iron and manganese removal.
34
Ground Water
Surface Water
Combined
No of Plants Surveyed
200
100
181
90
180
80
160
N
o
70
140
o
f
60
120
50
100
40
80
%
60
30
54
20
19
10
40
28
36
18
P
l
a
n
t
s
S
u
r
v
e
y
e
d
20
13
13
0
0
Limpopo
Mpumalanga
North West
Free State
KwaZulu Natal* Eastern Cape Western Cape
RSA
Fig. 3.2 Types of Water Sources in Small Treatment Plants surveyed in South Africa
3.3.4
Water treatment practices
Conventional water treatment processes were generally used in the majority of the plants surveyed.
In some of the plants that abstracted groundwater, the only form of treatment practiced was
disinfection. Interestingly, one of the small water treatments surveyed was a desalination plant
which was close to Port Alfred in the Eastern Cape and fell under the control of the Albany Water
Board. The plant used membrane filtration followed by disinfection with chlorine. The unit
processes and methods of disinfection used in the various treatment plants are summarized in Fig.
3.3 -3.11 with the details captured in appendix 3.2.
Coagulation – In terms of coagulation, the survey has confirmed a general trend in South Africa
where there has been a strong move towards the use of polyelectrolyte as a substitute for alum and
ferric chloride with 69% of the plant surveyed now using these chemicals. The Free State had the
highest usage of polyelectrolyte where 92% of the plants are currently using these coagulants. The
Western Cape was the highest user of Alum (61%) and the North-West province showing the
35
highest user of ferric chloride (22%) (Fig. 3.3).
Filtration – Sixty percent of the small treatment plants surveyed used rapid gravity filtration
systems with a further 24% using pressure filters. Only nine percent of the plants were using slow
sand filtration systems. It was interesting to find that 14 plants were using diatomaceous earth
filters which are predominantly used in large municipal swimming pool systems. The North-West
province had the highest (31%) application of slow sand filtration while the Western Cape had the
lowest (8%). No sand filtration systems were used in Limpopo, Mpumalanga and Free State which
had the highest application of rapid gravity filtration (Fig. 3.4).
Disinfection – Chlorine gas was found to be the most popular disinfectant with 69% of the small
treatment plants using this chemical, followed by sodium hypochlorite (15%) and calcium
hypochlorite (HTH) (14%).
The highest application of sodium hypochlorite was found in
KwaZulu-Natal (40%) followed by Free State (31%). The highest application of HTH was found in
the Eastern Cape (33%). No application of sodium hypochlorite was found in Limpopo,
Mpumalanga and Western Cape. Only one instance of the application of chlorine dioxide, sodium
bromide and ozone was found in the country at the following plants: Wild Coast Casino, Libode
and Jeffreys Bay, respectively (Fig. 3.5).
36
Polyelectrolyte
Alum
Ferric Chloride
Ferric + Polyelectrolyte
Alum + Polyelectrolyte
No of Plants Surveyed
100
200
181
90
%
180
80
160
70
140
60
120
50
100
40
80
30
60
54
20
40
36
28
10
19
18
20
13
13
0
0
Limpopo
Mpumalanga
North West
Free State
Kwazulu Natal
Eastern Cape
Western Cape
RSA
Fig. 3.3 Types of Coagulants used in Small Treatment Plants Surveyed in South Africa
Fig. 3.4 Types of Filters used in Small Treatment Plants in South Africa
37
N
o
o
f
P
l
a
n
t
s
S
u
r
v
e
y
e
d
Chlorine Gas
HTH
Sodium hypochlorite
Chlorine Dioxide
Ozone
Bromine
No of Plants Surveyed
90
200
181
80
180
160
70
N
o
140 o
f
60
P
120 l
a
n
50
100 t
%
s
40
80
30
60
54
20
40
36
S
u
r
v
e
y
e
d
28
10
19
18
20
13
13
0
0
Limpopo
Mpumalanga
North West
Free State
KwaZulu Natal
Eastern Cape
Western Cape
RSA
Fig. 3.5 Types of Disinfectants used in Small Treatment Plants in South Africa
3.3.5 Quality of drinking water produced by small water treatment plants
3.3.5.1 Physicochemical compliance
Appendix 3.3 shows in detail the physicochemical quality of drinking water produced by small
waterworks visited during the study period. These include pH, conductivity, turbidity and chlorine
residual. The results of the analyses for all water samples collected at various plants fell within
SANS Class I in terms of pH (5 to 9.5) and conductivity (<150 mS/m) (SANS 241, 2005).
For efficient disinfection, the DWAF, HOD and WRC’ s Assessment Guide for the Quality
of Domestic Water Supply (1998) recommends that the turbidity of drinking water should be less
than 1 NTU and preferably less than 0.5 NTU. The maximum turbidity limit allowable by SANS
241 ranges between 1 and 5 NTU (2005). Water samples collected at the point of treatments
showed that 44% and 38% of the small water treatments surveyed in South Africa fell within
SANS Class I (< 1 NTU) and Class II (1-5 NTU), respectively. The remained plants had turbidity
values higher than 5 NTU (Fig.3.12). At the point of consumption, 46% and 41% of the plants fell
within Class I and Class II, respectively (Fig. 3.7). The highest turbidity compliance was noted in
Free State at both point of treatment (Class I: 73% of the plants and Class II: 27%) and consumer’s
taps (Class I: 69% of the plants, Class II: 31% of the plants). In this province, no small water
treatment plant exceeded the maximum turbidity limits allowed by SANS 241.
38
Class 1
Class 2
< 1 NTU
Class 2
1 to 5 NTU
> 5 NTU
No of Plants Surveyed
80
200
181
70
180
160
60
140
50
120
%
40
100
80
30
54
60
20
40
36
N
o
o
f
P
l
a
n
t
s
S
u
r
v
e
y
e
d
28
10
19
18
20
13
13
0
0
Limpopo
Mpumalanga
North West
Free State
Kwazulu Natal
Eastern Cape
Western Cape
RSA
Name of Province
Fig. 3.6 Turbidity Compliance of Small Treatment Plants surveyed in South Africa at the
Point of Treatment
The high turbidity compliance in the Free State Province might be attributed to the partnership that
has been established between this province and a technical support organization (CSIR). This
technical support visits each plant at least once per month to advise the operators on process control
issues. The lowest turbidity compliance was noted in the Eastern Cape Province with 40% and 31%
of the plants showing the highest turbidity values at the point of treatment and at the point of use,
respectively. The turbidity values recorded from most water samples collected in these plants
exceeded the allowable maximum limits set by SANS 241:2005.
39
Class 1
< 1 NTU
Class 2
1 to 5 NTU
Class 2
> 5 NTU
No of Plants Surveyed
80
200
181
70
180
160
60
140
50
120
40
100
%
80
30
54
20
60
36
40
28
19
10
18
13
13
N
o
o
f
P
l
a
n
t
s
S
u
r
v
e
y
e
d
20
0
0
Limpopo
Mpumalanga
North West
Free State
Kwazulu Natal
Eastern Cape
Western Cape
RSA
Name of Province
Fig. 3.7 Turbidity Compliance of Small Treatment Plants Surveyed in South Africa in
Distribution system
North-West had 28% of the plants not complying with the maximum turbidity limits at the point of
treatment as well as at the point of use. Mpumalanga and Western Cape had 39% and 42% of the
plants falling within Class II at both points of treatment and points of use, respectively (Figs. 3.12 13).
As indicated in Appendix 3.2, high turbidity values interfered with the concentrations of free
chlorine residual at the point of treatment as well as at the point of use. This made it more difficult
to maintain an adequate residual which could protect the drinking water against pathogenic microorganisms. Free chlorine residual is the primary indicator of microbial safety used in process
controls. Adequate disinfection then requires a free chlorine concentration of at least 0.5 mg/l in the
final water leaving the plant after a contact time of at least 30 min at pH less than 8 (Water
Research Commission, 1998; WHO, 2004) . The free chlorine residual concentration at the point of
delivery should be at least 0.2 mg/l under normal circumstances and 0.5 mg/l during periods of high
risk of microbial contamination (WHO, 2004). To combat any possible contamination in the
network and to protect public health, the South African’s Assessment Guide for the Quality of
Domestic Water Supply recommends the ideal target range of 0.3 -0.6 mg/L free chlorine residual at
the consumer’s tap water (Water Research Commission, 1998). This was not the case in 44% of the
plants visited during the survey (Figs.3.14- 3.16).
40
Chlorine at Point of Treatement <= 0.5
Chlorine at Point of Treatement <= 0.1
Chlorine at Point of Use <= 0.2
Chlorine at Point of Use <= 0.1
90
80
Percentage Below Stipualted Limit
70
60
50
40
30
20
10
0
Limpopo
Mpumalanga
North West
Free State
Kwazulu Natal
Eastern Cape
Western Cape
RSA
Fig. 3.8 Free Chlorine per Province at Point of Use and Point of Treatment
Water samples collected at the point of treatment indicated that 16% of the plants had a minimum
free chlorine concentration ≤ 0.1 mg/l and 56% had a free chlorine concentration ≤ 0.5 mg/l. At the
point of use 32% of the plants had free chlorine concentrations below 0.1 mg/l and 48% had below
2 mg/l in each province as shown in Fig. 3.8. Figures 3.15 and 3.16 show the histograms of the free
chlorine concentrations as distributed across the entire country at the point of treatment and at the
point of use.
60
120.00%
50
100.00%
Frequency
Cumulative %
Frequency
40
80.00%
30
60.00%
20
40.00%
10
20.00%
Free Chlorine mg/l
Fig. 3.9 Free Chlorine Histogram for all Provinces at Point of Treatment
41
4
M
or
e
3.
5
3
2.
5
2
1.
5
1
0.
9
0.
8
0.
7
0.
6
0.
5
0.
4
0.
3
0.00%
0.
2
0.
1
0
It was noted that many operators were not aware of the chlorine dose added in the raw water after
filtration and in most of the plants the flow rate of the intake water was not known. Many of the
plants either overdosed the chlorine or under chlorinated the drinking water and this led to chlorine
values outside the recommended limits (Appendix 3.3).
Frequency
Frequency
Cumulative %
60
120.00%
50
100.00%
40
80.00%
30
60.00%
20
40.00%
10
20.00%
0
0.00%
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8 0.9
1
1.5
Free Chlorine mg/l
2
2.5
3
3.5
4
More
Fig. 3.10 Free Chlorine Histogram at Point of use across all Provinces
3.3.5.2 Microbiological compliance
It is important to note that the quality of water reaching consumers depends not only on operating
conditions at the treatment plant but also on changes that can occur in the distribution system.
During the survey period, it was noted that final drinking water of the highest quality might be
leaving some plants but its condition deteriorated to some extent before it reached the consumers
(Appendix 3.4). Given sufficient time, the chlorine residual concentration decreased to a very low
level that did not comply with the South African standard. High turbidity in the finished water, old
pipes, breaks in distribution pipelines, biofilm growth, sludge accumulation in the storage reservoirs
and the availability of nutrients for microbiological growth could be among the factors that
accelerate the chlorine residual decay of final drinking water at the point of use (Momba et al.,
2000).
To ensure the absence of bacterial pathogens, the drinking water should be free of faecal
organisms. The primary bacterial indicator recommended for this purpose is the coliform group of
organisms (DWAF, 1996; WHO, 2004; SANS 241, 2005). Total and faecal coliforms are used
much more than any other indicator group for monitoring drinking water quality because they
address both health and treatment efficiency objectives. Although as a group, they are not
42
exclusively of faecal origin, they are universally present in large numbers in the faeces of human
and other warm blooded animals. The presence of faecal coliforms in treated water indicates poor or
inadequate treatment of drinking water. Higher concentrations of faecal coliforms in treated water
indicate a high risk of contracting waterborne disease, even if small amounts of the water are
consumed (DWAF, 1996).
Figures 3.17-3.18 and Appendix 3.4 illustrate the microbiological quality of water supplied
by plants surveyed. It must however be stressed that these results were once off surveys which were
repeated in some provinces. Due to logistics and the costs involved, repeated analyses could not be
done over the entire country. Despite these shortcomings it must be emphasized that once off
surveys are a good indicator of the microbiological quality of the water produced by the plants
surveyed. In many instances this was also the first time water samples from these all treatment
plants were being analyzed and this is an indicative of major shortcomings in the legislation in
South Africa. Recent developments within DWAF do however show that there is now increased
emphasis on monitoring of drinking water quality. The Delmas incident in South Africa in 2005
resulted in 600 cases of typhoid, five documented deaths, and 3300 cases of diarrhoea. Escherichia
coli were found in one of the town’s reservoirs and the lack of treatments, especially chlorination,
was found to be a major contributing factor to the tragedy (Water Wheel, November/December
2005).
In Mpumalanga, 95% of the plants at the point of treatment and 84% at point of use
complied with the South African water quality standard in terms of total colifoms. Seventy four
percent of the plants were within the limits recommended by South African standards in terms of
faecal coliforms at both the point of treatments and the point of use. Total coliform counts ranged
between 0 and 380 cfu/100 ml at the point of treatment and between 0 and 180 cfu/100 ml at the
point of use, while faecal coliform counts ranged between 0 and 3 cfu/100 ml at the point of
treatment and between 0 and 12 cfu/100 ml at the point of use.
In Limpopo, 64% of the plants at the pint of treatment and 94% at point of use of the plants
complied with the South African recommended standard in terms of total coliforms. The total
coliform counts ranged between 0 and 3.6 × 103 cfu/100 ml at the point of treatment and between 0
and 250 cfu/100 ml at the point of use. In terms of faecal coliforms, 73% and 88% of the plants
complied with South African drinking water recommended limits at the point of treatment and at
the point of use, respectively.
Faecal coliform counts ranged between 0 and 60 cfu/100 ml and
between 0 and 7 cfu/100 ml at the point of treatment and at the point of use, respectively.
43
Total Plants Surveyed
Faecal Coliform Compliance (%)(<1 cfu/100 ml)
Total Coliform Compliance (%) (<10 cfu/100ml)
120
200
180
173
100
160
140
80
o
f
P
l
120 a
%
n
t
100 s
60
80
40
60
53
20
N
o
40
33
S
u
r
v
e
y
e
d
28
19
11
20
17
12
0
0
Limpopo
Mpumalanga
Free State
North West
KZN
Eastern Cape
Western Cape
RSA
Name of Province
Fig. 3.11 Bacteriological Compliance at the Point of Treatment
In the North-West province, 76% of the samples from the plants at point of treatment and 53% at
the point of use complied with the South African recommended limits in terms of total coliforms.
Total coliforms ranged between 0 and 83 cfu/100 ml at the point of treatment and between 0 and
288 cfu/100 ml at the point of use. A total of 94% and 83% of the plants were found within the
recommended limits for faecal coliforms at the point of treatment and at the point of use
respectively. Faecal coliform counts ranged between 0 to 5 cfu/100 ml and between 0 to 13 cfu/
100 ml at the point of treatment and at the point of use, respectively.
44
Total Coliform Compliance (%) (<10 cfu/100ml)
Faecal Coliform Compliance (%)(<1 cfu/100 ml)
Total Plants Surveyed
120
200
180
174
100
160 N
o
140 o
f
80
120 P
l
a
n
100
t
s
%
60
80
40
60
53
40
20
33
28
19
11
S
u
r
v
e
y
e
d
20
17
13
0
0
Limpopo
Mpumalanga
Free State
North West
KZN
Eastern Cape
Western Cape
RSA
Name of Province
Fig. 3.12 Bacteriological Compliance in Distribution System
The microbiological data of the plants visited in the Free State province resulted in 100%
compliance with the SANS Standard in terms of total coliforms and faecal coliforms at the point of
treatment. At the point of use 92% compliance was obtained in terms of total coliforms and 85%
compliance in terms of faecal coliforms. The above non-compliance represented two points in the
distribution system and it must be noted that overall the plants in the Free State were producing
excellent water quality.
In KwaZulu-Natal, 57% of the plants at point of treatment complied with the SANS
Standard in terms of total coliforms and 61% complied in terms of faecal coliforms. At the point of
use, 64% plant compliance was obtained in terms of total and faecal coliforms. Total coliform
counts ranging up to 866 cfu/100 ml were detected at one site at the point of treatment with
corresponding faecal coliform counts of 53 cfu/100 ml. At the point of use an alarmingly high total
coliform count of 2419 cfu/100 ml was detected at one of the sites with a corresponding faecal
coliform count of 36cfu/100 ml. The primary cause of this failure was due to either lack of
chlorination facilities or under-dosing of chlorine.
In the Eastern Cape Province, at the point of treatment 28% of the plants complied with the
SANS standard in terms of total coliforms and 34% complied in terms of faecal coliforms. At the
point of use 20% of the plants complied in terms total coliforms and 29% complied in terms of
faecal coliforms. Total coliform counts ranging up to 240 cfu/100 ml were noted at the point of
treatment of one of the plants and 223 cfu/100 ml at one of the points in the distribution system. A
maximum faecal coliform count of 25 cfu/100 ml was detected at one of the points of treatment
while 98 cfu/100 ml was noted at one of the points in the distribution system.
45
In the Western Cape, at the point of treatment 50% of the plants complied in terms of total
coliforms and 25% complied in terms of faecal coliforms. In the distribution system, there was 25%
compliance in terms of both total and faecal coliforms. Total coliform counts ranged between 0 and
59 cfu/100 ml at the point of treatment and between 1 and 67 cfu/100 ml at the point of use, while
the faecal coliform counts ranged between 0 and 25 cfu/100 ml and between 0 and 50 cfu/100 ml at
the point of treatment and at the point of use, respectively.
Compared to other provinces, the Eastern Cape Province produced the lowest potable
drinking water quality in terms of both total and faecal coliforms while the Free State produced the
best drinking water quality. These results confirm the poor microbiological quality of the drinking
water in the Eastern Cape that was also noted by Momba and co-workers (2004) in a previous study
conducted in the Alice Water Treatment plant.
3.3.6
Control and monitoring
Water treatment plant operators are all aware that the characteristics of the raw water they are
treating changes from time to time. While the quality of borehole water tends to remain fairly
constant, the quality of raw water extracted directly from rivers can change drastically, especially in
terms of suspended solids. Even the change in temperature from winter to summer can also
influence the treatment of drinking water (e.g. it is harder to form floc in cold water than in
summer). Furthermore, there are variations in water demand which may require changes in raw
water flow rate. Consequently, operators need to make adjustments to the operation of the plant
from time to time in order to meet changing treatment requirements. They also need to check that
the adjustments made are consistent with the desired effect (Momba and Brouckaert, 2005).
In Limpopo and Mpumalanga, most of the operators and supervisors interviewed did not
have a good knowledge of the flow rate at which their plants were being operated. Generally the
chemical dosing rates were determined by experience. Very few knew what their chemical dose
rates were or how to calculate them. Coagulant doses were adjusted manually, usually based on the
appearance of the floc and sometimes also based on the taste of the water when alum was used.
Chlorine doses were set manually and some plants were overdosing chlorine. Nearly all of the
plants reported that an external monitoring group (the District Municipality, BNK, MMP or some
private company) visited the plants approximately once a month although most plants complained
about a lack of feedback from the external monitors. Most of the plants were partially automated
which facilitated the operator's work and limited some overdosing errors and ensured that remote
reservoirs were kept full. In Mpumalanga, most plants had instruments to measure turbidity, pH and
46
chlorine residual although these were not always used. The maintenance of equipment in some
plants was not taken into account.
In the North-West Province, 60% of the plants were equipped with raw water flow meters;
however readings were only recorded in plants owned by Water Boards and in three of the
municipal owned plants. It was noted that 66% of the plants had jar stirrers on-site; however these
were only used in four of the plants. Less than 20% of the supervisors and operators knew the
required chemical dosing rates or how to calculate them. Chemical dosages were adjusted based on
the appearance of the floc and the colour of the finished water. All the plants were measuring
chlorine residuals, however less than half of them were measuring turbidity and pH. Only one plant
was testing the general chemical and microbiological quality of water. Four municipal plants were
monitored by local health inspectors; however the plant staffs were not getting any feedback on the
water quality results. Nearly all of the plants reported that an external monitoring group visited the
plants approximately once a month, but they did not know what kind of tests they were doing and
they were not getting any feedback. The Botshelo water owned plants were equipped with a
telemetry system and Supervisory Control And Data Analysis (SCADA) system for the monitoring
of the whole plant.
In the Free State, some of the operators and supervisors interviewed knew the flow rates at
which their plants operated but very few knew what their chemical dose rates were or how to
calculate them. Seventy percent of the plants had the instruments to measure turbidity, pH and
chlorine residual. Fourteen percent of the plants measured chlorine only, and 14% do not have any
on-site monitoring programme. All of those plant operators interviewed were aware of the
importance of measuring these parameters but were typically unable to persuade the municipality to
buy the instruments (however, basic instruments usually came with major upgrades). A number of
supervisors were using swimming pool test kits to measure pH and chlorine. Coagulant doses were
adjusted manually usually based on the appearance of the floc. However in one case, the dosage of
the flocculants was automatically controlled by an ion charge analyzer. Chlorine doses were also set
manually. In one case the Supervisor at a plant was reluctant to increase the chlorine dosage even
though the chlorine levels in the town were low. All of the plants visited during the survey period
were monitored by an external monitoring group (CSIR) on a monthly basis.
In KwaZulu-Natal, 15% of the plants had functioning raw water meters, 10% had installed
meters but were non-functional, and operators indicated that the meters had been non-functional for
many years. Lack of maintenance of equipment was reported in 80% of the plants. Seventy percent
of the plants were not able to calculate the chemical doses and the operators were running the plants
by visual observation of the clarifier overflow. Only 20% of the plants had on-line instruments for
47
measuring turbidity and pH and 70% had bench scale equipment for measuring pH, turbidity and
chlorine. On-site jar test equipment was recorded in 5% of the plants, however only 2% were
capable of conducting a jar test. None of the plants were undertaking chlorine demand tests on site.
External Process Audits were undertaken at 30% of the plants and involved a detailed assessment of
the plant optimization. These plants were mainly plants managed by Water Boards such as Umgeni
Water and Umhlatuze Water. Seventy percent of the plants were measuring process parameters and
capturing onto daily log-sheets, however limited quality control of this data was practiced. At plants
managed by Water Boards, Process Technicians visited the plants at least once a month to assist
with optimization of the plant. The Process Technicians were responsible for a number of plants and
rotated their service between the plants. In the larger Water Boards, Process Engineers and Process
Scientists were available at short notice for trouble shooting process problems as well as to follow
up on water quality failures. Supervisors and Works Managers were only available at 20% of the
plants that were visited.
In the Eastern Cape Province, 50% of the operators and supervisors interviewed knew the
flow-rates at which their plants operated, 78% did not know the chemical doses used or how to
correlate the required dose to the flow rate, 46% had the instruments to measure turbidity, pH and
chlorine residual, 3% of the supervisors were using swimming pool test kits to measure pH and
chlorine, 95% of the plants reported that an external monitoring group visited the plants
approximately once a month; however most plants complained about a lack of feedback and 20% of
the plants were partially automated.
In the Western Cape, all the plants were equipped with raw water flow meters. Most of the
operators reported that raw water flow was adjusted if there was high demand of water or during
rain seasons. The majority of the plants owned jar stirrers. Almost all the plants were measuring
chlorine residuals and pH, however less than half of the plants were measuring the turbidity of the
water. Some of the plants were testing the general chemical quality of water and only one plant was
testing E. coli onsite. Nearly all of the plants reported that an external monitoring group visited the
plants approximately once a month and they were getting feedback. More than a half of the plants
visited during the study period were equipped with a SCADA and telemetry system to monitor the
whole plant.
To provide a guide for a simple log sheet system for effective control and monitoring, the
Tables presented below are suggested. The purpose of this type of log is to record all process
changes that take place on the plant. This helps to ensure that sufficient information is recorded to
pass onto the next operator that comes on shift. Typical details that would be recorded include,
Time of arrival on plant, condition of the plant on arrival, reservoir levels, record of person visiting
48
the plant, reasons for making process control changes, etc.
TABLE 3.1
Date
Time
EXAMPLE OF A PROCESS CONTROL SHIFT LOG SHEET
Plant Name:
Operator Name:
Raw water
Turbidity
Raw water
pH
Coagulant
Dose
Clarifier
turbidity
Chlorine
dose
Final water
chlorine
Lime
dose
06H00
08H00
10H00
12H00
14H00
16H00
18H00
20H00
22H00
00H00
02H00
04H00
TABLE 3.2
EXAMPLE OF FILTER WASHING AND CLARIFIER SOLIDS MANAGEMENT
Date
Plant Name:
Operator Name:
Time
Filter No
Backwash Volume Used (m3)
Clarifier No
Time Desludged
06H00
6
53.5
3
5 minutes
08H00
10H00
12H00
14H00
16H00
18H00
20H00
22H00
00H00
02H00
04H00
49
Final
water
pH
TABLE 3.3
EXAMPLE OF DAILY OPERATOR LOG
Date
Plant Name
Operator Name
Time
Description of Situation in the plant
06H00
Arrived on plant – everything in order, final water turbidity 0.3 NTU,
final chlorine 1.2 mg/l, final pH 8.4
06H35
Call received from City Engineer – Water shortage in city reservoir –
started pumps to city
07H10
Raw water turbidity increased from 45 NTU to 90NTU – undertook jar
test – optimum dose of 11 mg/l – set plant on new dose
08H30
3.4
New dose working well – good clarifier overflow turbidity
RECOMMENDATIONS FROM THE SURVEY
It is concluded that although ownership of the plants belonged to 4 categories owners such as the
District/Local Municipalities, DWAF, DOH and private companies (Water Board), over 80% of the
plants were noted to be owned by the District Municipalities. In addition, about 84% of the small
water treatment plants in the designated provinces abstracted their raw water from surface water.
Conventional water treatment processes were generally employed; over 80% of the small water
treatments employed the rapid gravity and pressure filtration systems. Chlorine gas was observed to
be the most common disinfectant used (69%), followed by sodium hypochlorite (15%) and calcium
hypochlorite (14%). Furthermore, a substantial number of the small water treatment plants engaged
operators with limited technical understanding of the treatment processes, leading to either an
overdose or an under-dose of coagulant and chlorine. Generally in terms of microbiological
parameters employed, Free State and Eastern Cape Provinces produced the safest and poorest water
quality respectively.
Finally some of the small water treatment plants were devoid of basic
monitoring equipment such flow meter, pH meter, jar test apparatus, turbidity meter, chlorine meter
and colorimeter. These have led to lack of flow rate, turbidity, pH and chlorine residual
measurements.
It is strongly recommended that the following operational practices be implemented:
1. All small water treatment plants must be provided with basic functioning raw and final
water flow meters installed.
2. Accurate records of flow into and out of the plant must be recorded on a daily basis or
whenever a change in flow rate is made.
50
3. All the treatment plants must acquire jar stirrer apparatus to determine the optimum dose of
the coagulants. Jar tests must be conducted at least once per week or when the raw water
quality changes.
4. Plant operators must monitor pH at various points in the plant for coagulation control. The
turbidity of the final water must be monitored and falls within Class 1. This can only be
achieved if the operators target a filtrate turbidity of < 1NTU.
5. The chlorine dose has to be applied proportionally to the plant flow rate. To ensure effective
disinfection, measurement of the chlorine demand of water is highly recommended.
6. For a monitoring programme to be effective, each small water treatment plant must be
equipped with a jar stirrer, turbidity meter, pH meter and a chlorine meter. A programme for
monitoring the physico-chemical (at least pH, temperature, turbidity and free chlorine
residual) and bacterial (coliform bacteria, especially faecal coliform) quality of water at the
point of treatment and various sites of the distribution systems must be established.
51
CHAPTER IV
WATER QUALITY CHANGES IN THE DISTRIBUTION SYSTEM
The distribution system is often vital in determining the final quality of potable water.
Deterioration of drinking water quality during storage or in distribution systems is one of the major
difficulties experienced by potable water supplies worldwide (Momba et al., 2000). The proper
understanding, characterization and prediction of water quality behavior in drinking water
distribution systems are critical in meeting regulatory requirements and ensuring customers oriented
expectation. Realizing that the water quality after treatment deteriorates with time, the distributor
cannot always guarantee the quality at the end of the distribution network. Moreover the reservoirs
which are an important part of the distribution network represent the final point at which the water
quality can be modified before it reaches the consumer (Momba et al., 2000).
This part of the study provides a reference compendium on parameters affecting the quality
of final treated drinking water in the distribution systems of three small water supplies (Seymour,
Fort Beaufort and Alice). The Fort Beaufort, Seymour and Alice water treatment plants are all
located in the Nkonkobe Municipality, in the Eastern Cape Province of South Africa. The Fort
Beaufort plant has the highest number of distribution reservoirs (26) serving 15 villages in its
distribution system. The water distribution system of Seymour consists of two storage reservoirs
located in the water treatment plant and an associated primary and secondary distribution network.
The Alice water treatment plant was selected to evaluate the effectiveness of previous operator
training that had been conducted at the plant in 2004.
4.1
METHODOLOGY
To identify the major problems resulting in water quality changes in distribution systems, an on-site
evaluation of the operating conditions at Fort Beaufort, Seymour and Alice water treatment plants
in the Eastern Cape Province was conducted by visual inspection, interviews and use of
questionnaires from October 2005 to November 2005.
4.1.1 Measurement of the flow of raw water and coagulant dose
The flow rates were recorded and in the absence of the flow meter (Seymour did not have a flow
meter while the one for Alice was malfunctioning at the time of the visit), the flow of the raw water
was calculated using the existing 90° V notch weir according to Kawamura (1991). For a 90o Vnotch weir, the total flow rate ( Q) is related to the height of the crest over the weir (H) as follows:
52
Q (m3/s) = 1.40 H2.5
The jar test was used to determine the optimum dose of the coagulant.
4.1.2
Physicochemical and Microbiological Analysis
Physicochemical parameters determined on-site included: chlorine concentrations, pH, temperature
and turbidity. The initial chlorine dose and free chlorine residual concentrations were determined at
the point of the treatment and in the distribution networks using a multi parameter ion specific
meter (Hanna-BDH laboratory supplies). The pH, temperature and the turbidity were measured at
each step in the treatment processes and in the distribution networks using a pH meter, thermometer
and a microprocessor turbidity meter (HACH company, model 2100P) respectively.
For microbiological analysis, water samples were collected according to standard
procedures using sterile bottles, which contained sodium thiosulphate (ca 17.5 mg/l), placed in
cooler boxes and transported to the laboratory for analysis within 2 to 4 h after collection. Standard
methods were used to quantify total and faecal coliforms and heterotrophic plate count bacteria.
4.2
RESULTS AND DISCUSSION
4.2.1
Distribution networks
Schematic diagrams of the Fort Beaufort and Alice distribution systems are shown in Fig. 4.1 and
4.2, respectively.
The Fort Beaufort plant had three main reservoirs (No1-3) with a combined capacity of
6.3 Ml. These reservoirs were filled by high lift pumping of the clear water (Fig. 4.1). From the
main reservoirs, water was fed by either gravity or pumping to a number of service reservoirs. The
topography of the distribution allowed gravity feed from service reservoirs.
The Seymour plant had two storage reservoirs with a total capacity of about 400 m3.
Reservoirs, ventilation, scour valves and overflows were adequately designed. However, there were
no bulk sale meters or reservoir level indicators. The water was supplied by gravity to the
community in which the service levels were mainly yard and house connections. During interviews,
operators reported that the locations of the scour valves in the network were not known. Hence the
network could be flushed and it was suspected that the reservoirs had high levels of silt.
53
R8
Hillside
R1
PS2
R3
R5
Bhofolo
R2
WW
PS2
PS3
R9
R9
New town
Fort Beaufort
Town
Fig. 4.1 Schematic diagrams of the Fort Beaufort Distribution Network (WW – Water Works,
R1 – Rectangular balancing reservoir [2.3 ML], R2 - Circular Reservoir near plant [2.0 Ml], R3 –
Circular reservoir near plant [2.0 Ml], R4 – Hillside reservoir, R5 – Reservoir feeding Ntobela, R7 –
Bhofolo Reservoirs [2.5 Ml supply], R8 – Ntobela Reservoir supplying 14 Satellite reservoirs, R9 –
Newtown Reservoir, PS1 – Pump station No 1, PS2 - Pump station No 2, PS3 - Pump station No 3,
R1-3 – Has 1.6 Ml/d supply).
The Alice Plant had a capacity of 7 Ml/d. Five of the town’s seven reservoirs, including the main
reservoir were gravity fed. Float valves regulated the flows into the reservoirs and they operated
essentially at 100% capacity under normal conditions. The flow to Ntselamanzi and Mavuso
reservoirs was augmented by pumping which was initiated automatically based on the signals from
level sensors in their reservoirs.
54
S a m p lin g p o in ts
AW TP
Pum p
S ta tio n
M e te r
1 ML
B a la n c in g
Tank
M e te r
M a v u so
2 .5 M L
M a v u so
V illa g e
G o lf C o u rse
D e v e lo p m e n t
M a in
6 ML
A lice
N ew
H appy
R e st
0 .7 M L
D a v id so n P rim a ry
M a in L in e
M e te r
H a p p y R e st
H illc re st
F o rte
F la ts
N tse la m anzi
1 .5 M L
M e te r
M e te r
M e te r
Pum p
S ta tio n
O ld
H appy
R e st
0 .2 M L
C lin ic
V ic to ria
E a st
C lin ic
0 .6 M L
V ic to ria
E a st
N tse la m a n z i
V illa g e
U FH
Fig 4.2 Schematic diagrams of the Alice distribution network
4.2.2
Water Treatment Plant operation conditions
4.2.2.1 Fort Beaufort water treatment plant
The Fort Beaufort water treatment plant abstracted its intake water from Kat River. The raw water
turbidity varied between 60 and 70 NTU, but reached 100 NTU during the rainy season. The flow
rate of the raw water measured by an ultrasonic flow meter varied between 66 and 80 l/s during the
investigation. The accuracy of the flow meter checked by measuring the height over the V-notch
weir was found to be acceptable (0.069 m3/s = 69 L/s). After coagulation with a blended polyamine,
water passed through two circular clarifiers. Settled water was then filtered in seven rapid gravity
filters followed by final chlorination. The supplier was the only person who made adjustments to
the chemical dose. The standby dosing pump had been removed for repairs a year ago.
A jar test done during the study period confirmed a dosage of 45 ml/30 s which was
adequate for the flow of 66 l/s. Dosing took place downstream of a weir proving good mixing
energy. Of concern was the fact that the operators were not in a position to measure the applied
dose while a jar stirrer was available on-site.
Calculations undertaken showed that the clarifier surface loading rates ranged between 1.8
and 2.21 m/h which was well above the design rate of 1 m/h. Sludge removal valves were
malfunctioning and the clarifier overflow turbidity ranged between 8 and 10 NTU, well above the
guideline of 5 NTU.
55
Filtration rates were found to be between 1.2 and 1.4 m/h well below the design of 5 m/h. This
impacted on the turbidity of filtered water which was above 1 NTU. Gas chlorination was used for
disinfection. One chlorinator was available with no standby. There were no emergency stocks of
HTH. At the time of the visit the chlorinator was not working and a makeshift HTH dosing system
was in use, however there was no means of measuring the dose.
A the point of treatment, the Fort Beaufort chlorine dosing unit available read a dosing rate
of 1.2 kg/h (333.3 mg/s). The dosage in mg/l from the plant inflow when chlorine gas was being
dosed corresponded to 5.05 mg/l. Typical dosages usually do not exceed 1.5 - 2.0 mg/l. The high
dosage calculated could be due to the following reasons: i) the dosing equipment being
malfunctioning and ii) high chlorine demand of the water. The average free chlorine residual
concentration was therefore ≤ 1.5 mg/l.
4.2.2.2 Seymour Water Treatment Plant
The Seymour water treatment plant abstracted its intake water from Kat River. The raw water had
the turbidity values ranging between 50 and 70 NTU. The raw water flow measurement took place
at the head of waterworks and was found to be functional. At the time of visit, an average inflow
rate of 5.38 l/s was recorded. A blended polymeric coagulant was dosed at a weir followed by the
baffled flocculation basin and the horizontal flow rectangular sedimentation basin. The Surface
Loading Rate (SLR) of the sedimentation tanks was found to be 0.3 m/h well within the guideline
of 1 m/h. One dosing pumps was available with no standby and coagulant control was done by the
suppliers. No jar stirrer was available at the plant, but the jar tests undertaken during the study
period indicated that the dose was adequate (8.5 ml/60 s) for the flow rate of 5.38 l/s. Following
slow sand filtration, the water was chlorinated before distribution. The two slow sand filters were
operating at 0.3 m/h which was just on the upper limit for these types of filters. Filtered water had
turbidity values below 1 NTU. Filter cleaning was done monthly and the procedure was in-line with
standard practice.
On-site electrolytic chlorination using salt as a feed was used for disinfection. Operators
could not calculate the applied dose. During the visit, the chlorine dosage could not be determined
as the operation and the specification manual for the equipment were not available. However, the
free residual chlorine determined from the in-plant reservoir was 0.5 mg/l. According to the
operators, occasional shortages of salt were common. No emergency or backup HTH stock was
available. Bench pH, chlorine and turbidity meters that cost about R20 000 each were available but
were surprisingly not in use due to the lack of batteries.
56
4.2.2.3 Alice Water Treatment Plant
Raw water was abstracted from a dam, and after coagulation with a polymer the water passed
through a flocculator and horizontal sedimentation tanks. This was followed by filtration through
two valveless filters and gas chlorination. Raw water turbidity at the time of the assessment was
20 NTU. An ultrasonic flow meter was used to measure the flow rate of the raw water over a Vnotch at the head of works. The flow rate of raw water was 75 l/s and jar tests confirmed that the
applied dose was correct (15 ml/30 s). Flocculation was poor and the poor flow distribution was
overloading some of the sedimentation tanks.
The chlorination system for Alice water treatment plant was similar to that of Fort Beaufort.
Residual chlorine levels at the point of treatment ranged between 0.24 and 0.89 mg/lL after the
contact tank.
4.2.3
Drinking water quality in the distribution systems
4.2.3.1 Turbidity compliance
Figure 4.3 summarizes the turbidity results obtained in the Fort Beaufort distribution system. None
of the water samples had the turbidity values below 0.2 NTU, with 27% of the samples having a
turbidity ≤ 0.5 NTU. Most of the samples (86%) had turbidity values below 1 NTU with only 6%
being above 2.5 NTU. An uncharacteristically high turbidity was observed once from the Henrietta
control point (49.3 NTU), which was suspected to be a consequence of a damaged pipe along the
route.
In Seymour distribution networks, the turbidity of the drinking water at the various sampling
points varied very markedly in the range of 0.55 to 27 NTU. Figure 4.4 shows that none of the
samples had turbidity values below 0.2 NTU, 13% of the samples were below 0.5 NTU, 67% of the
samples had turbidity greater than 1 NTU and 14% had turbidity higher than 5 NTU.
Figure 4.5 depicts a histogram of turbidity in the Alice distribution system. The data show
that none of the samples had turbidity below 0.2 NTU; 58% of the samples had turbidity values
≤ 1.0 NTU and 30% of the samples had turbidity values higher than 2.5 NTU. This indicates that
the consumers were receiving unsafe water and the primary reasons for this were poor plant
management as there was always a shortage of the primary coagulant and chlorine at this water
works.
57
35
120.00%
30
100.00%
25
Frequency
Cumulative %
Frequency
80.00%
20
60.00%
15
40.00%
10
20.00%
5
0
0.00%
0.1
0.2
0.5
0.75
1
1.5
NTU
2
2.5
5
10
More
Fig. 4.3 Histogram of Turbidity in the Fort Beaufort Drinking Water Distribution System
8
120.00%
7
100.00%
6
Frequency
Cumulative %
80.00%
Frequency
5
4
60.00%
3
40.00%
2
20.00%
1
0
0.00%
0.1
0.2
0.5
0.75
1
1.5
2
2.5
5
10
More
NTU
Fig. 4.4 Histogram of Turbidity in the Seymour Drinking Water Distribution System
8
120.00%
7
100.00%
6
Frequency
Cumulative %
80.00%
Frequency
5
4
60.00%
3
40.00%
2
20.00%
1
0
0.00%
0.1
0.2
0.5
0.75
1
1.5
2
2.5
5
10
More
NTU
Fig. 4.5 Histogram of Turbidity in the Alice Drinking Water Distribution System
58
4.2.3.2 Free chlorine residual concentration and microbiological characteristic in the
distribution systems
Fort Beaufort - Figure 4.6 depicts a histogram of the free chlorine concentrations and it was noted
that 28% of the results were below 0.1 mg/l, indicating that there was a large reduction in the
concentration of free chlorine residual from the treatment plant which supplied water with a free
chlorine residual concentration up to 1.5 mg/l. Ninety two percent of the samples had free chlorine
concentrations below 0.5 mg/l and were thus within the recommended levels of between 0.3 and 0.6
mg/l (Water Research Commission, 1998).
No coliform bacteria were observed in the in-plant reservoirs of the Fort Beaufort water
treatment plant during the study period. However in the distribution system, 60% of the samples
had less than 10 cfu/100 ml total coliforms. Of concern was the 7% of the samples that had more
than a 100 cfu/100 ml total coliforms (Fig. 4.7). Figure 4.8 shows a histogram of the faecal
coliforms in the Fort Beaufort system, where 4% of the samples had five or more faecal coliforms,
due to the depletion of chlorine residuals in the distribution networks.
In general 88% of the water samples had more than the DWAF (1996) limits of 100 cfu/mL
HPC (Fig.4.9). These results were an indicative of low chlorine residuals, possible regrowth of
bacteria and poor maintenance of the distribution system.
59
Figure 4.6: Fort Beaufort Free Chlorine Histogram
Figure 4.7 Fort Beaufort Total Coliform Histogram
Cumulative %
Frequency
25
F re q u e n c y
20
100.00%
20
120.00%
100.00%
80.00%
Cumulative %
Frequency
15
120.00%
25
80.00%
15
60.00%
60.00%
10
10
40.00%
5
40.00%
5
20.00%
0
0.00%
0.1
0.2
0.5
0.75
1
1.5
2
2.5
20.00%
0
0.00%
0
More
1
10
100
Free Chlorine
500
1000
Mor e
Figure 4.9 Fort Beaufort Histogram of Heterotrophic Plate Counts
Figure 4.8 Fort Beaufort Faecal Coliforms Histogram
60
120.00%
30
50
100.00%
25
Frequency
100.00%
20
Cumulative %
80.00%
40
80.00%
Frequency
Frequency
Frequency
200
Tot al Colif or m
Cumulative %
30
60.00%
20
40.00%
10
20.00%
0
1
5
10
15
20
15
60.00%
10
40.00%
5
20.00%
0
0.00%
0
120.00%
0.00%
100
More
1000
10000
100000 1000000
More
Heterotrophic plate count
Faecal Coliform Bins
Figs 4.6-4.9 Histograms of Free Chlorine Residual and Indicator Bacteria in the Fort Beaufort Drinking Water
Distribution System
Seymour - In terms of free chlorine, the Seymour histogram (Fig. 4.10) shows that 20% of the
samples had a free chlorine concentration below 0.1 mg/l, a further 20% had concentrations
between 0.1 and 0.2 mg/l. Overall all the water samples had a concentration below 0.5 mg/L, while
two samples had concentrations of 0.75 and 1.0 mg/l respectively.
Eight of the 14 water samples analysed (60%) had no total coliforms, however 22% had 10
or more total coliforms (Fig.4.11). Figure 4.12 depicts the Seymour histogram for faecal coliforms
which shows that 12 of the 14 samples (85%) had no faecal coliforms whereas only two samples
had five or more.
In terms of faecal coliforms, this system showed the most promising results and was an
indicative of the smaller distribution network associated with shorter retention times. In terms of
HPC, Fig. 4.13 shows that 12% of the samples had HPC densities greater than 105 cfu/ml, 50% of
the samples had more than 104 cfu/ml HPC and 58% had more than 103 cfu/ml. Overall 65% of the
60
water samples did not meet the guideline value of 100 cfu/ml also showing that the distribution
network was in need of a good clean out.
Figure 4.11 Histogram of Total Colif orms in the Seymour
Distribution System
Figure 4.10 His togram of Free Chlorine in the
Seym our Dis tribution Sys tem
6
Frequency
Cumulative %
100.00%
100.00%
7
80.00%
4
40.00%
2
1
20.00%
0
0.00%
0.1
0.2 0.5 0.75
1
1.5
2
80.00%
6
60.00%
3
5
60.00%
4
40.00%
3
2
20.00%
1
0
2.5 More
0.00%
0
1
10
Free Chlorine
14
5
100.00%
95.00%
4
80.00%
3
60.00%
2
40.00%
80.00%
1
20.00%
75.00%
0
90.00%
6
85.00%
4
2
0
15
20
Cumulative %
100.00%
8
10
1000 More
120.00%
Frequency
Frequency
Frequency
10
5
500
6
Cumulative %
12
1
200
Figure 4.13 Histogram of HPC in Seymour Distribution
System
105.00%
0
100
Total Colif orm
Figure 4.12 Histogram of Faecal Colif orms in
Seymour Distribution System
Frequency
Cumulative %
Frequency
8
Frequency
Frequency
5
120.00%
9
120.00%
7
More
0.00%
100
Faecal Colif orm
1000
10000 1000001000000 More
Heterotrophic plate count
Fig 4.10 - 4.13 Histograms of Free Chlorine Residual and Indicator Bacteria in the Seymour Drinking Water
Distribution System
Alice - Figure 4.14 shows that 27% of the samples had residual free chlorine concentration below
0.1 mg/l, 62% below 0.2 mg/l and none of the water samples having more than 1.0 mg/l. In terms of
total coliforms (Fig. 4.15), 27% of the water samples had no coliforms with 56% having more than
the recommended limit of 10 cfu/100 ml. Of major concern was the fact that 6% of the
aforementioned samples had more than 200 cfu/100 ml, representing a major health risk to the
community.
61
Figure 4.14 Histogram of Residual Free Chlorine in
Distribution system
8
120.00%
7
Frequency
Cumulative %
6
120.00%
100.00%
6
Frequency
80.00%
4
60.00%
3
40.00%
2
80.00%
5
60.00%
4
3
40.00%
2
1
0
0.1
0.2
0.5
0.75
1
1.5
2
2.5
20.00%
1
0.00%
0
20.00%
0.00%
0
More
1
10
Figure 4.16 His togram of Faecal Coliform s in
the Alice Dis tribution Sys tem
12
200
500 1000 More
Figure 4.17 His togram of HPC in Alice
Dis tribution Sys tem
120.00%
10
7
Frequency
60.00%
4
40.00%
2
100.00%
8
80.00%
6
Cumulative %
Frequency
9
100.00%
8
120.00%
10
Cumulative %
Frequency
100
Total Colif orm
Free Chlorine
Frequency
Cumulative %
Frequency
7
100.00%
5
Frequency
Figure 4.15 Histogram of Total Colif orm in Alice
Distrbution System
80.00%
6
60.00%
5
4
40.00%
3
2
20.00%
20.00%
1
0
0.00%
0
1
5
10
15
20
0
More
0.00%
100
Faecal Colif orm
1000
10000 1000001000000 More
HPC
Fig 4.14 - 4.17 Histograms of Free Chlorine Residual and Indicator Bacteria in the Alice Drinking Water
Distribution System
The faecal coliform histogram of the Alice distribution system in Figure 4.16 shows that 55% of the
samples had no faecal coliforms present, however 34% of the samples had more than one faecal
coliform. Of the aforementioned samples, 6% had more than 5 faecal coliforms confirming the
major consumer risk mentioned above. In terms of HPC in Alice (Figure 4.17), 6% of the samples
had more than 104 cfu/ml, 17% had more 103 cfu/ml and 50% of the samples had more than the
recommended limit of 100 cfu/ml.
Based on the chlorine rates at the dosing points and the concentrations of free residual
chlorine in networks systems, relationships were then established between both points. When in
operation, the plant chlorination systems always provided sufficient residual chlorine for areas near
the main reservoirs. For the areas that were far away from the main reservoirs, the plant chlorination
systems usually provided sufficient residual free chlorine on the days of supply/pumping to the
service reservoirs. The dosages at the plants were not sufficient enough to combat the depletion of
62
free chlorine residual in most reservoirs when the final water was detained for more than 24 h. This
was attributed to the chlorine consumption by floc/sediment accumulations in most reservoirs.
Moreover, it was found that the reservoir designs were generally adequate. They were
equipped with overflows, air vents and drainage facilities. The operation of reservoirs, however,
seemed to be inadequate. Although the plant chlorination systems gave adequate dosage at the point
of dosing, these dosages were not sustained in the distribution systems.
4.3
CONCLUSIONS
In general, the assessment of the quality of drinking water in distribution systems of Fort Beaufort,
Seymour and Alice revealed that most of the sampling points in distribution systems did not comply
with the required standards in terms of indicator bacteria such as heterotrophic plate counts, total
coliforms and faecal coliforms. This was a reflection of the inconsistency in the plant operations,
which made impossible for the plants to ensure sustainable production of good quality of drinking
water. Several factors could be responsible for this phenomenon:
i) The design and operational of the flocculation processes were not optimized at all plants.
This led to inadequate floc formation for the sedimentation process.
ii) The monitoring and adjustment of chemical dosages (coagulants and chlorine) were not
conducted on-site; operators should be capacitated to adjust dosing rates with respect to inflow and
quality changes
iii) Filtration process monitoring and control was not optimized. The filtration rate of the
SSF in Seymour was 100% higher than the accepted upper limit.
In all the plants, there was no standby dosing pumps for the coagulants and disinfection
chemicals. The stocking of disinfection chemicals was not sustainable and lack of on-site water
quality data which should assist in making critical decisions and also estimations in times of
emergency.
The above factors in water treatment plants impacted on the effectiveness of the disinfection
process in the distribution systems and the following major problems were recorded:
i) the
distribution system of the pipe network did not show acceptable levels of residual free chlorine and
ii) most of the chlorine dosed at the treatment plant was consumed by the floc sludge that
accumulated in the reservoirs and the deposits that were present in the distribution pipe network.
4.4
RECOMMENDATIONS
To improve disinfection efficiency in Fort Beaufort, Seymour and Alice drinking water treatment
plants, this study suggests the following recommendations:
63
Floc sludge removal need to be done twice for the Seymour WTP and adequate flocculation
basins need to be introduced at the Fort Beaufort WTP. The quality of inflow to each filter should
be monitored to prevent overloading the filtration process and the quality of the effluent be
monitored from each filter. The concept of filtering-to-waste must be investigated after the
backwashing of the slow sand filters at Fort Beaufort and Seymour. The effectiveness of these
filters with respect to turbidity removal within 1 to 2 h after backwashing was usually low and the
filtered water should then be sent to waste until turbidity levels become acceptable (< 1 NTU).
The reservoirs need to be maintained and cleaned regularly to ensure that there is no sludge
accumulation. The sludge consumes the disinfectant thus reducing the residual chlorine and
compromising the reliability of the disinfection in the network. Some reservoirs showed leakages.
Replacement of screens on vents needs to be done annually. The pipe network system needs to be
drained or flashed as required to remove deposits that also consume disinfectants. Scour valves for
various sections of the network must be located and put to use.
A comprehensive water quality monitoring programme needs to be developed and supported
by the Municipality. Water distribution networks need to be documented in order to understand and
optimize their operation. At the time of visit, network drawings could not be obtained and there
were no records of pressure and bulk water meter readings. Record keeping and interpretations need
to be enhanced at all plants as this would assist in taking critical operation, maintenance and
management decisions.
Operators should be trained to perform key tasks such residual monitoring, adjustment of
chemical dosages, flow measurements and visual analysis of the water quality from each unit
process, independently. Each shift should have two operators; this is important to reduce the
consequences of accidents and also for morale and motivation purposes.
The Alice case is clearly one of a loss of team towards compliance of the operational
procedures, having been beneficiary of a training programme in the past year that significantly
improved the plant’s performance and the quality of the final water produced (Momba et al., 2004;
2005). This underscores the need for a regular auditing of the plants performance to ensure
continuous improvement and safe drinking water.
64
CHAPTER V
MANAGEMENT ISSUES AFFECTING THE EFFICIENCY OF DISINFECTION
IN SOUTH AFRICAN SMALL WATER TREATMENT PLANTS
5.1
INTRODUCTION
The capacity of any water treatment plant to provide acceptable drinking water quality mainly
depends on the performance of each functional unit in the plant including coagulation-flocculation,
sedimentation, filtration and disinfection. Management and administration of water treatment plants
also play an important role in determining the quality of the final water. In urban areas, drinking
water quality complies with the South African National Standards (SANS) 241 Drinking Water
Specification (2005). This water, therefore, does not pose a significant risk to public health over a
lifetime of consumption. The difficulties experienced in training and retaining adequately skilled
people to run water treatment plants in impoverished rural municipalities, as well as lack of
revenues needed to hire experienced managers and to maintain and upgrade water supplies have
been among the major hurdles to providing safe and clean drinking water in these areas. Inadequate
manpower training and periodic updating of knowledge and skills affect institutional capacity to
implement sustainable water resource management. Poor maintenance practices, inadequate
improvement in working conditions and poor water programme monitoring are hallmarks of
inadequate manpower training or institutional capacity. This chapter therefore seeks to explore
management issues facing safe and reliable water supply in rural areas and some peri-urban areas of
South Africa.
5.2
METHODOLOGY
A survey of management issues of 181 small water treatment plants across seven provinces of
South Africa (including Limpopo, Mpumalanga, North-West, Free State, KwaZulu-Natal, Eastern
Cape and Western Cape) was conducted from June 2004 to December 2005. The survey started
with a short introductory meeting following by interview with the plant operators, superintendents
and supervisors of the plants. Information concerning management issues such as the training of
the operators, their salaries, benefits, decision making, maintenance practices and financial capacity
(for the purchase of chemicals/upgrading of infrastructure), data recording, documentation and
communication were sought through the use of questionnaires. The above-mentioned plant staffs
present at the time of survey were interviewed individually.
65
5.3
RESULTS AND DISCUSSION
5.3.1
Poor Maintenance Practices
Lack of maintenance of equipment was noted to be a major management problem. About 60% of
the SWTP operators interviewed in all the provinces studied (Eastern Cape, Free State, Western
Cape, Mpumalanga and Limpopo Provinces) mentioned that equipments were not regularly
maintained. This led to periodic equipment failures and the consequences of poor water quality.
Indeed some operators asserted that the culture in most SWTPs was a culture of repairs or
replacement of equipments and not maintenance of equipment. Several factors have been implicated
to fan the poor maintenance culture. Such factors included lack of technical skills and appropriate
training, inadequate or lack of relevant experience, inadequate funds and personnel. For example in
North-West, Western Cape, Free State, KwaZulu-Natal, Eastern Cape, Mpumalanga and Limpopo
Provinces, between 5.88-46.30% of the operators reportedly had educational qualifications of
standard 8, 42-62% with Matric (with the exception of KwaZulu-Natal – 80%) whereas
0-53% were enrolled in post Matric qualifications. The implications of these trends are enormous
because they typify the shortcomings and potential dangers in the water delivery system due to lack
of appropriate qualification and training. The in-service training component is exemplified by the
fact that in all the SWTPs studied, in the respective provinces, about 7-63% of the operators had not
undergone relevant and appropriate training to enable them acquire technical skills for the job
(Table 5.1).
The main role of operators is to control the equipment and processes that remove or destroy
harmful chemical compounds and micro-organisms from the water. This role is therefore mired in
controversy because most of the operators lack technical knowledge of the equipment and technical
processes. Some operators were not aware of how to determine flow rates, chlorine dosage or even
the concept of chlorination as well as maintenance of technical equipments, measurement and
documentation of processes. Above all, they lacked computational skills in an era of a rapidly
changing information technology system. The ripple effects of these shortcomings can not therefore
be ignored and should indeed be placed in the context of the reported management problems in
some Local Government Authorities (LGAs) in South Africa.
66
TABLE 5.1
SOME NON-TECHNICAL ISSUES IMPACTING ON QUALITY OF WATER SERVICES DELIVERY IN SMALL
WATER TREATMENT PLANTS IN SOUTH AFRICA
Province
Operator’s qualification (%)
Std 8
Matric
Post
Experience (years) (%)
<5
5-10
11+
Matric
Salary (pm) (%) (Rand)
1000-
3000-
5000
2000
4000
+
Training %
Yes
No
LP
28 .0
56.0
22.0
32.0
34.2
38.0
32.3
41.0
16.0
53.0
47.0
MP
23 .0
51.0
20.0
29 .3
33.0
31.0
30.0
44.3
14.2
56.0
44.0
NW
18.37
61.22
20.41
37.50
34.38
28.12
36.59
48.78
14.63
50.0
50.0
FS
39.13
60.87
0
27.28
36.36
36.36
35.70
57.15
7.15
75.0
25.0
KZN
5.88
80.39
13.73
32.26
25.81
41.94
30.43
47.83
21.74
36.84
63.16
EC
46.30
42.60
11.10
30.51
23.73
45.76
26.0
66.0
8.0
36.73
63.27
WC
10.53
36.84
52.63
28.57
38.10
33.33
12.50
50
37.50
92.31
7.61
5.3.2
Training and Capacity Building
Lack of technical skill has been highlighted as one of the major challenges to sustained quality
water provision. Potential areas for capacity development include technical, managerial, marketing
and public relations. This challenge underscores the need for upgrading and training of personnel
but this has not been actively pursued by SWTPs in all the provinces studied (Table 1). For better
coverage of the training programme, a training of training model could be used. This training
should be task specific and guided by the contents of related policy documents and guidelines such
as the Water Services Act – 1997, Strategic Framework for Water Services and Guidelines for
Compulsory National Norms and Standards for Water tariff. The need for training is underscored by
the inability of plant operators to calculate chlorine doses and calibrate or maintain equipments
(Momba et al., 2004a; b; Momba et al., 2005b; c). This issue is compounded by shortage of human
resource capacity in over 70% of SWTPs visited in the designated provinces.
Coordinated efforts should equally be put in place to maximize the human resource capacity
available in water provision support systems in the provinces. Such efforts could be achieved
through strategic partnerships with relevant support agencies. Such partners could include academic
institutions, research bodies, community social networks, CBOs, NGOs and relevant government
departments. Partnership with research and academic institutions also offers opportunities for
technical assistance and manpower through internship programmes where suitably prepared
students and research fellows can take part in water supply activities (Momba and Brouckaert,
67
2005; Momba et al., 2005c). Capacity building should therefore cover a range of issues such as
technical, social, finance, managerial and institutional (WHiRL, 2003).
Specific technical needs of the treatment plants could include development of computational
skills for plant operators, dosing calculations, calibration, operation and maintenance of technical
equipments, measurement and documentation of processes and the interpretation of records or
reports, measuring flow rate and use of instruments.
5.3.3 Poor Working Conditions
Poor working conditions were also cited to hamper water services delivery. Poor working
conditions were reflected as lack of comprehensive Medical Aid Scheme for operators, inadequate
in-service training and capacitation, lack of motivation of operators by senior management,
bureaucratic processes and poor salaries. In terms of salaries, about 12% - 37% of the operators
earned between R1 000 and R2 000 per month while 40% to 66% earned between R3 000 and
R4 000 per month and less than 40% earned above R5 000 in the SWTPs studied in the designated
provinces (Table 5.1).
In the wake of inflation, a salary range of between R1 000 and R2 000 for a staff member
with over 10 years of working experience on the same job may not be adequate. Further salary
increases are contingent on additional education attainments but this is apparently unattainable
because job entry qualifications were rudimentary and current schemes for upward educational
mobility or in-service capacitation are either non-existent or not implemented in some of the
SWTPs visited across the designated provinces. This creates a situation of frustration and burnout
due to lack of relevant education, training, skills development and performance of routine duties
over years and poor incentives.
5.3.4
Insufficient financial capacity
South Africa promotes free access to a safe and reliable source of water. The implementation of this
policy operates by placing deferential tariffs on the rich to cater for the indigents. This policy
challenges the capital requirement for water service operation and maintenance given the chances of
inadequate production cost recovery. The viability of this policy and possible service expansion are
predicated on the number of the rich who can afford to pay for water supply and sanitation as well
as continued government commitment. Inadequate budgeting and financing was also noted to
hamper service delivery in SWTP studied in the province. In virtually all the SWTPs in the
designated provinces studied, inadequate funding for operational and implementation activities was
mentioned as huge drawbacks for effective and efficient water services delivery. For example,
68
inadequate funding will affect maintenance culture, adequate stocking of water treatment chemicals,
repairs and replacement of faulty equipments, recruitment of personnel to tackle routine and
emergency issues. Although personnel interviewed were not aware of the level of funding or
budgeting for SWTPs, they were unanimous in asserting that funding was grossly inadequate or
mismanaged because, in most cases, operational activities were delayed or obviated due to lack of
funds.
Results of the survey have shown that chlorine is commonly used in small water treatment
plants. To improve for example the chlorination efficiency in water sector, estimated costs was
calculated taking into account the size and the design of the plant as well as the type of the
disinfectants. These estimated costs are illustrated in Tables 5.2-5.11.
5.3.5
Inadequate community involvement
Poor involvement of local communities was noted to be rampant at sub-national water service
provision levels. Community participation could inform technology choices, quality of service,
project citing and management structures. Experiences from community projects support that
community participation and involvement is critical to quality improvement and project
sustainability. Personnel from SWTPs mentioned that they did not interact regularly with their
respective communities to ascertain currency in problems encountered, concerns and to proffer
solutions. At best, they asserted that community involvement were informal and not coordinated.
Inadequate community involvement causes a lapse in relaying information on water quality,
management issues that may affect water distribution and inability to avoid or manage community
concerns and displeasures before they spill into protest actions or crises situations.
Sensitizing management practices to the above challenges is critical to their resolution and
the enhancement of safe and reliable water supply. On this note, the above factors solicit peculiar
management strategies and priorities.
5.3.6
Streamlining Duties and Job Description
Although the job profiles of the role players in the water services delivery are clearly defined (Table
4.12), respondents at the various SWTPs maintained that the organogram was not often adhered to
and this results in perceived overlap of activities. The significance of the organogram is that it
facilitates accountability, efficient tracing of possible causes of system failures and precision in
response. For instance, in the event of poor maintenance resulting to system failures, factors such as
lack of funding or skills or negligence at a particular level of water distribution could be easily
69
implicated. This framework would ultimately suggest clear cut ways of dealing with the identified
problems.
The need for streamlining duties and responsibilities is reiterated by the potential dangers of
dereliction of duty due to reported overlap of responsibilities of water plant operators and
supervisors. It is important to highlight that the lack of manpower challenges the streamlining of
duties and functions, as already discussed elsewhere in this chapter. Recruitment and retention of
competent staff is hence vital. Figure 5.1 below illustrates a typical organogram for water service
production.
To facilitate the performance of the roles and responsibilities above, competent individuals
should be recruited to serve in the various positions; position specific roles and responsibilities as
well as organisational chain of command should be clearly stated to respective employees.
Employees should also be conversant with disaster and emergency plans as well routine operational
activities.
District Municipality (WSA)
Local Municipality (WSP)
Municipal Manager
Manager Engineering Services
Supervisor
Maintenance Department
Operator/Shift Worker
Operator/Shift Worker
Plant 1
Plant 2
Fig. 5.1 Organogram for Water Service management
70
5.3.7
Poor Recording, Documentation and Communication
Beyond the mechanical components in safe water supply, maintaining the quality of water supply is
equally affected by the availability of adequate stocks of water treatment chemicals. For instance,
an interruption in the supply of coagulants or disinfectants was the case in some SWTPs studied
either due to system failures or unavailability would constitute a major emergency. To avoid this
danger, proper recording of the rate of use of the various chemicals and actual stock taking by water
treatment plant operators and timely replenishment is essential. This should also be closely
monitored by higher authorities. However, respondents of the various SWTPs studied noted poor
recording and documentation by different levels of management as the principal causes for stock
depletion or interruption of supply of chemicals, reagents and equipments. In most cases, operators
lacked knowledge of the exact inventory of chemicals, reagents and equipments. This lack of
knowledge will obviously lead to various stock depletions, with ripple effects on quality of service
delivery.
In the event of the distribution of unsafe water, appropriate emergency plan should be
instituted to avert or minimize the effect of the poor water quality. Such plans would initially
consist of emergency prevention measures which are mostly related to plant maintenance, strikes
and sabotage, natural disasters, equipment failures, ensuring adequate supply of chemicals, and
various measures to protect the water treatment and distribution systems. Unfortunately over 50%
of the operators were not aware of the existence of emergency prevention methods. This was
generally attributed to poor communication between operators and management or operators and
consumers. In fact poor water quality is not communicated to consumers. Suspected poor water
quality or other problems should be communicated to the community and management in order to
avoid disease outbreaks as was recently reported in Delmas, Mpumalanga. Effective
communication ensures buy-in of relevant stakeholders, community sensitization and awareness
and building of strategies to address pertinent issues such as the need to boil water or to treat water,
by ant other method, in households for suspected poor water quality.
5.3.8 Emergency plans
The plan should equally have a detailed description of the role and responsibilities of the different
participants in water service provision (from the district WSA to plant operators/shift workers and
community members). Efficient communication protocols should also be built into the emergency
and routine plans. Such communication protocols should include internal communication
procedures and public communication procedures.
Outside emergency situations, communication between water service providers and the
71
public is critical in ensuring quality service. Through this, community participation and
empowerment are facilitated. The sustainability of water supply projects is promoted by proper
communication. Different community communication methods include education and awareness
programmes, efficient consumer complain channels and emergency warning systems. It has been
reported that internal and external communications were not in their best in most SWTPs (WHiRL,
2003).
5.4
RECOMMENDATIONS
Given the above water resource management improvement priorities, there is a need to conduct
competency assessments and appropriate training programmes for water service providers and
regulators. The training programmes should also cover roles and responsibility clarification,
information and communication systems. The development and implementation of operational
checklists and protocols are equally essential to ensure timely ordering of materials (particularly
chemicals) and the maintenance of equipment. Increased funding to SWTPs as well as enhancement
of working conditions of personnel is also recommended. An urgent adoption of suitable water
quality management protocols by the WSAs is critical for quality improvement and assurance.
72
TABLE 5.2
CALCIUM HYPOCHLORITE CAPITAL COSTS
Typical
Calcium Hypochlorite (HTH) Dosing System
No.
Basis for design
Size
Process flow rate
2.50
Ml/d
Chlorine dose required
7
mg/l Cl2
No of days per year
365
Daily consumption
17.50
kg/d Cl2
Solution strength
5
% (m/v)
No. batches prepared per day
1
Volume solution required per day
0.35
m3
Tank diameter (assume diameter 1 m)
1
m
Area of tank
0.79
m2
Height of tank
0.45
m
Allow free board of 0.3 m
0.30
m
Total height of tank
0.75
m
Required
Cost (R)
Estimated cost on 1 m3 tank
No.
Number of tanks required
Unit Cost
Required
Cost
Preparation tank size
1
Cost of preparation tank
R5 000
2
R10 000
Baffles for make up tank
R2 000
2
R4 000
Constant head tank size
0.02
Cost of constant head tank
R5 000
2
R10 000
Axial flow mixers
R15 000
2
R30 000
20 mm PVC pipework
1 000
1
R1 000
Electrical
10 000
1
R10 000
Fitting and installation
20 000
1
R20 000
m3
m3
Total capital costs
R85 000
73
TABLE 5.3
CALCIUM HYPOCHLORITE OPERATING COSTS
Design Flow Rate
Process
Ml/d
Units
50
kg drums
(incl VAT)
16.00
R/kg
Purity % Cl2
68%
%(m/m)
Unit cost (R/kg) as chlorine (Cl2)
23.53
R/kg Cl2
Dose
7
mg/l Cl2
No. days per year
365
Daily consumption
17.50
kg/day
Annual consumption as chlorine (Cl2)
6387.50
kg/year
Annual consumption as chlorine (Cl2)
6.39
tons per year
Annual cost Rands per year
150 294.12
R/year
Cost per kl
16.47
Cents/kl
Calcium hypochlorite unit of supply
Unit cost (R/kg) calcium hypochlorite as delivered
TABLE 5.4
TOTAL OPERATING COSTS FOR CALCIUM HYPOCHLORITE DOSING SYSTEM
Fixed Capital Costs
Item description
Total
Purchased equipment (installed)
R85 000
Civil & structural
R5 000
Total fixed capital investment
R90 000
Operating costs
Item Description
R/y
cents/kl
Direct chemical cost
R150 294
16.47
Maintenance
R5 000
0.55
Direct operating costs
R155 294
17.02
Depreciation
20%
Fixed charges: depreciation (20%)
R18 000
1.97
Total annual operating costs
R328 588
36.01
74
TABLE 5.5
DESIGN OF TYPICAL SODIUM HYPOCHLORITE DOSING SYSTEM
Average daily inflow
Ml/d
2.5
Average inflow
Ml/y
913
Chlorine dose
mg/l
7
Chlorine dose
kg/Ml
7
Chlorine consumption
tons p/a
6.39
Mass balance
Min
Average
Max
Inflow
Ml/d
1.50
2.50
3.00
Chlorine dosage
mg/l
7.00
7.00
7.00
Chlorine dosage rate required
kg/d Cl2
10.50
17.50
21.00
NaOCl specific gravity
kg/l
1.05
1.05
1.05
Sodium hypochlorite - available
% (m/v)
10.00
10.00
10.00
chlorine sold as 13-16%, but loses
strength very quickly - use 10 % as
average
Sodium
hypochlorite
dosage l/d
105.00
175.00
210.00
hypochlorite
dosage l/h
4.38
7.29
8.75
Min
Average
Max
required
Sodium
required
Storage capacity
NaOCl consumption
l/d
105.00
175.00
210.00
NaOCl consumption
m3/d
0.11
0.18
0.21
Maximum supplier off-line time
D
15.00
15.00
15.00
1.58
2.63
3.15
Min
storage
required
cap. m3
Required
Minimum bulk tank size
Tanker load (as 12% delivered but m3 NaOCl
2
calculations based on 10% as it
loses strength quite quickly)
Safety factor
0.25
Tank size for accepting delivery
m3
2.50
Equivalent chlorine delivered
kg Cl2
200.0
75
TABLE 5.6
OPERATING COSTS OF TYPICAL SODIUM HYPOCHLORITE DOSING SYSTEM
l
25
Cost as delivered
R/l NaOCl
R2.40
Sodium hypochlorite
R/kg NaOCl
R2.29
Sodium hypochlorite empty container price
R/l container
R57.00
Contribution of cost of container to overall price
R/l container
2.28
Sodium hypochlorite total price as delivered
R/l NaOCl
R4.68
Chlorine total price as delivered
R/kg Cl2
R46.80
Chlorine cost (delivered)
R/ton Cl2
R46 800
Chlorine cost per annum
R/y
R298 935
Total inflow (based on average inflow)
Ml/y
912.50
Chemical costs R/annum
R298 935
Direct annual operating costs
R308 935
Total annual operating costs
R317 455
76
TABLE 5.7
FIXED CAPITAL AND ANNUAL OPERATING COSTS OF SODIUM
HYPOCHLORITE DOSING SYSTEM
Item Description
No. of
Unit Cost
Total
Purchased equipment (installed)
R15 800
Bulk storage tanks, 2 m3 GRP
2
R3 ,000
R6 000
Day tank, 0.1 m3, GRP
1
R800
R800
Dosing pumps
2
R4 000
R8 000
Piping & fittings (PVC, C16)
R1 000
Electrical & instrumentation
R6 800
Level transmitter
2
R3 000
R6 000
Installation
1
R800
R800
Civil & structural
R20 000
Bund & plinth
1
R4 000
R4 000
Total fixed capital investment
R42 600
Annual Operating Costs
R/y
cents/kl
Chemical cost of available chlorine
R298 935
32.76
Maintenance
R10 000
1.10
Direct operating costs
R308 935
33.86
Fixed charges : depreciation (20% pa)
R8 520
0.93
Total operating costs
R317 455
34.79
77
TABLE 5.8
GAS CHLORINATION OPERATING COSTS
Gas Chlorination Design Parameters
Quantity
Units
Unit cost (R/kg)
12.00
R/kg
Treated water flow rate
2.50
Ml/d
Purity (% Cl2)
100.00
%(m/m)
Dose (mg/l Cl2)
7
mg/l Cl2
Dose (kg/Ml)
7
kg/Ml
Daily chlorine gas consumption
17.50
kg/d
No of days per year
365
d/y
Annual consumption
6387.50
kg/y Cl2
Annual cost
R76 650
R/y
Cost per kl
8.40
cents/kl
Size of chlorinator
0.7
kg/h
78
TABLE 5.9
Description
GAS CHLORINATION SYSTEM – CAPITAL COST
Quantity Unit Rate
Amount
Cylinder manifold
2
R5 000
R10 000
Chlorinators, one duty and one standby.
2
R15 000
R30 000
Chlorine leak detector and alarm system dual sensor
1
R20 000
R20 000
chlorinator including connections
2
R4 000
R8 000
Heating & lagging
1
R5 000
R5 000
and chlorine injection sets, complete per spec.
1
R10 000
R10 000
1 Set breathing apparatus (gas respirators)
1
R20 000
R20 000
2 No. chlorine cylinders, 65 kg each filled
2
R8 400
R16 800
Scales
2
R10 000
R20 000
Exhaust fan, wall mounted capacity including controls
1
R15 000
R15 000
pipe, isolation valve and floor drainage system
1
R4 000
R4 000
1 No. first aid kit
1
R1 000
R1 000
1 Set warning and instruction signboards
1
R1 000
R1 000
4 No. filter cartridges for breathing apparatus.
4
R600
R2 400
2 No. chlorine gas injector.
2
R2 600
R5 200
4 No. set of 'O' rings for vacuum and dosing unit.
4
R4 100
R16 400
Duty/standby operating water booster bumps for
Supply, delivery, installation and testing of the
chlorination pipework, valves, fittings, water take-over
Emergency shower including eyewash, water supply
Spare Parts and Repair Fittings
Total
R184 800
79
TABLE 5.10
TOTAL OPERATING COSTS FOR GAS CHLORINATOR
Fixed Capital Costs
Item Description
Total
Purchased equipment (installed)
R184 800
Civil & structural
R10 000
Total fixed capital investment
R194 800
Operating costs
R/yr
cents/kl
Chemical cost
R76 650
8.40
Maintenance
R10 000
1.10
Direct operating costs
R86 650
9.50
Fixed charges: depreciation (20%)
R38 960
4.27
Total operating costs
R125 610
13.77
TABLE 5.11
COST COMPARISON OF DISINFECTION ALTERNATIVES
Gas/liquid
Sodium
Calcium
Chlorination
Hypochlorite
Hypochlorite
Capital cost
R194 800
R317 455
R90 000
Direct operating Cost (c/kl)
9.50
33.86
17.02
Maintenance (c/kl)
1.10
1.10
0.55
Total operating cost (c/kl)
13.77
34.79
36.01
80
TABLE 5.12
ALLOCATION OF DUTIES AND RESPONSIBILITIES FOR
PERSONNEL IN WATER SECTOR
Position
Duties and Responsibilities
Plant operator
Conduct daily water treatment activities in
treatment plants
Supervisors
Oversee
plant
activities
and
operations;
procurement of materials; requisition for repairs
and maintenance and process control. Plant
operators are answerable to them
Water or engineering service manager
Staff training; ensure water sufficiency, monitor
the viability of treatment plants, co-ordination of
plant maintenance, and handling of consumer
complains, promotion norms and standards,
sharing of information from external sources.
Supervisors are answerable to them.
Municipality manager
Responsible for water safety, communication
with the public on water issues.
81
CHAPTER VI:
GENERAL CONCLUSIONS AND RECOMMENDATIONS
In general, the majority (over 80%) of the small water treatment plants surveyed in the designated
provinces were owned by the district municipalities. Virtually, the designed capacity of these plants
varied between 1 and 60 Ml/day; the smallest had 100 m3/day and the largest had 120 Ml/day. The
small water treatment plants abstracted their raw water from either surface or ground water or a
combination of both water sources with greater preponderance for surface water sources (over
84%).
Water treatment practices were noted to be the conventional type, mainly coagulation,
flocculation, sedimentation, filtration and disinfection. Two types of coagulants, namely
polyelectrolyte and alum, were commonly used by the variance water treatment plants across the
provinces studied. Rapid gravity filtration, pressure filter and slow sand filtration systems accounted
for 60%, 23% and 9% of the filtration systems across the provinces. Although disinfection practices
were commonly used by the majority of the plants, the most predominant types employed were
chlorine gas (69%) followed by calcium hypochlorite (14%). Chlorine dioxide, sodium bromide and
ozone were least used.
Over 50% of the various small water treatment plants investigated did not comply with the
SANS (2005) Class I (< 1 NTU) and Class II (1-5 NTU) recommended turbidity values. The
recommended target range of 0.3-0.6 mg/l free chlorine residual concentrations at the point of use
were not met, indicating the possibility of microbial contamination and its ripple effect on disease
transmission. It is concluded that about 70% of the small water treatment plants surveyed complied
with the SANS (2005) criteria of microbiological safety of drinking water, vis-à-vis total and fecal
coliforms.
Operational problems affecting the efficiency of small water treatment plants included: i)
inability to appropriately determine the flow rate, chemical dosage and turbidity, ii) lack of
chlorine residual at the point of use and lack of water quality monitoring.
Management issues affecting the efficiency of small water treatment plants included: i) lack
of skilled operators and inadequate training operators, ii) poor maintenance practices, iii) inadequate
improvement in working conditions and iv) poor water programme monitoring.
To produce safe drinking water and enhance the profile and quality of service delivery of
small water treatment, this study recommends the following:
Operational practices must be implemented in all small water treatment plants. Operators
82
need to make adjustments to the operation of the plant from time to time in order to meet changing
treatment requirements.
Flow meters should be installed at all small water treatment plants for periodic monitoring
of flow rates and for accurate determination of chemical dosages such as coagulants and chlorine.
All small water treatment plants should be endowed with basic microbiological and physicochemical equipment for monitoring of water quality parameters.
Evaluation and monitoring programmes should be done routinely as quality control
measures.
Adherence to a maintenance culture and increased budgetary allocation and in-service
training of the operators should be prioritized.
83
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88
Appendix 1
Section A: Plant Number
A01
Plant No.
A02
Database #
OFFICE USE ONLY
Section B: General Information
B01
Plant name
B02
Previous plant name
(if changed during
the past 10 years)
B03
Owner name
B04
Owner type
Municipal
DWAF
Other gov.
Urban
Peri-urban
Rural
Private
Postal address
B05
B06
Postal code
B07
Town / nearest town
B08
Locality
B09
Province
B10
Coordinates
B11
Contact person
B12
Telephone
B13
Fax
B14
E-mail
NS
EW
Section C: Plant Manager / Supervisor
C01
Name
C02
Qualifications
C03
Experience
yrs
Section D: Valid Date
D01
Survey Date
89
Farm
Park
Other (specify)
Section E: Plant History
E1
Year built
E2
Designer / supplier
E3
Age of plant
E4
Year upgraded
E5
Designer / supplier
E6
Age of upgrading
E7
Description of
upgrading
yrs
Section F: Capacity
F1
Design capacity
Ml/day
F2
Inflow
Ml/day
F3
Current flow
Ml/day
F4
Losses
F5
Population served
F6
DWAF Classification of
plant
Don't
know
Outflow
Ml/day
Don't
know
%
Don't
know
People
Section G: Raw water characteristics
Turbidity
G1
G2
Raw water type
(can be one or more
than one)
Raw water source
G3
Name of source
G4
Abstraction method
G5
G6
Colour
Salinity
Raw water turbidity
G8
Raw water pH
G9
Raw water colour
Algae
Alkalinity
x
Iron
Manganese
Nitrate
Fluoride
Other (specify)
Dam
River
Spring
Borehole
Sea
x
Presence of treated
wastewater
Presence of industrial
effluent
G7
Pollution
NTU
mg/l as Pt/Co / Hazen /
colour units
90
G10
Raw water alkalinity
mg/l as CaCO3
G11
Raw water conductivity
G12
Chemical properties
(mg/l)
G13
chlorophyll a
ug/l
G14
Raw water DOC
mg/l
G15
Taste and odour
TON
G16
Temperature
G17
DO
G18
Other (specify)
mS/m
TDS
Iron
Fluoride
Manganese
Nitrate
Hardness
°C
Section H: Treatment methods and chemicals, coagulation and disinfection
H1
Main
treatment
process
(can be more
than one)
Turbidity
removal
Colour
removal
Desalination
Stabilisation
/softening
Algae
removal
Nitrate removal
Fluoride
removal
Manganese
& Iron
removal
Taste &
odour
removal
Other (specify)
Chlorination
Ozonation
Aeration
Solids
removal
Other (specify)
H2
Pretreatment
processes
H3
Coagulation
H4
Coagulation
Condition
H5
Flocculation
H6
Visible Floc
Yes
No
pH adjustment
chemical
Lime
Soda ash
CO2
Other (specify)
Alum
Ferric
chloride
Ferric
sulphate
Poly-electrolite (specify)
PAC
Aluminium
Sodium Alum
Other (specify)
Hydraulic (open channel)
Good
Poor
Hydraulic (open channel)
Hydraulic (static in-line)
Good
Poor
Mechanical
Good
Hydraulic (pipe flocculation)
H9
Coagulant
type
91
Poor
Mechanical
H7
H8
Disinfection
H10
Cost of
Coagulation
System
H11
Installation Cost
H12
Maintenance Cost
H13
H14
H15
Dosing Pump
Make
Dosing Pump
Model
Dosing Pump
Model
H16
Dosing Point
H17
Dose mg/l
H18
H19
Condition of
Equipment
Power
Consumption
Watts
H20
H21
Flocculant type
H23
Disinfection/
Oxidation type
H24
Cost of
Disinfection
System
H25
Installation Cost
H26
Maintenance Cost
H27
H28
H29
Dosing Point
H31
Dose mg/l
H33
H34
H35
H36
Poor
Poor
Good
Liquid
Solid
Aeration
Chlorination
Dosing Pump
Make
Dosing Pump
Model
Dosing Pump
Model
H30
H32
Good
Condition of
Equipment
Power
Consumption
Watts
Backup
Disinfection
Disinfection
Contact Chamber
Poor
Good
Baffling
92
Specify type
Ozonation
Potassium
Permanganate
Hydrogen
peroxide
Other
(specify)
H37
Disinfection
Demand
H37
Settling type
H38
H39
H40
Flotation type
Horizontal
Upflow
Dissolved
air
Induced
air
Roughing
Rapid
sand
CATRIGE
BAG
Act Carbon
Act
Alumina
Filter type
Adsorption type
H41
Disinfection
chemical
H42
Stabilisation
chemical
H43
Advanced
treatment type
Chlorine
(gas)
Chlorine
(liq)
Lime
Soda ash
Sludge
blanket
N/A
SLOW
SAND
GRAITY
SAND
N/A
Chlorine
(solid)
Other
(specify)
Pulsator
High rate
UPFLOW
PRECOAT
OTHER (SPECIFY)
Ultraviolet
CO2
Limestone
RO
NF
Other
(specify)
Ozone
Other (specify)
X
IX
ED
UF
MF
Section J: Residuals management
J1
Methods of treatment
J2
Method of disposal
J3
Recycling
Coagulant
recovery
Recycling
of
residuals
streams
Discharge
to sewer
Drying bed
Sludge
dam
Sewer
Settling
Thickening
Other
(specify)
Land application
Section K: Operation
Fully
equipped
Partially
equipped
Basic instr.
Only
K1
Laboratory details
K2
Analyse acc to SABS
YES X
No
Don't Know
K3
Frequency of on-site
monitoring
Turbidity
Residual
chlorine
pH
93
None
Colour
Metals
Hardness
M: monthly, 2: every 2
months, 3: every 3 months,
A: annually W: once
weekly, D: once daily
Microbiological
Other (specify)
None
Turbidity
Frequency of
external monitoring
K4
M: monthly, 2: every 2
months, 3: every 3 months,
A: annually W: once
weekly, D: once daily
Residual
chlorine
pH
Microbiological
Colour
M
NAME OF COMPANY/
AUTHORITY
K5
Number of operators
required
Fulltime
Daytime
Part-time
K6
Number of actual
operators
Fulltime
Daytime
Part-time
K7
Operator
Qualification
Number of actual
Operators
Number of Support &
Maintenance Staff
K9
Plant Operation
Manual Available on
Plant
K10
Hardness
Other (specify)
K5
K8
Metals
NQF2 - Std 8
NQF2
NQF4
NQF5
NQF4 - Std 10 (Matric)
Std 5
Mech Tech
Elec Tech
NQF5 - Matric + 2
Proc Tech
Workshop Tools
Available on Plant
Available in Municipal Stores
Section S: Staff Retention
Operator 1
S01
Salary
S02
Experience on this
plant - Years
S03
Experience as an
Operator incl other
plants
S04
Do the operators
udergo training ?
S05
Training Provider
S06
Frequency of
Operator 2
Operator 3
Yes
Internal
External
6 mths
12 mths
94
24 mths
Operator 4
Operator 5
Training
S07
Type of Training
S08
Automation
S09
External monitoring
(Name of Company /
Authority)
Technical
Admin
Management
Fully
Partial
Manual
Section T: Filtration
T01
No of Filters
T02
Type of media
T03
Media Size
T04
Filter type
T05
T06
Flow Pattern onto
Filter
Frequency of
Backwash
T07
Recycle
T08
Automated
Section R: Costs
R01
Original Capital
Cost of Plant
R02
Chemical
treatment Costs
R03
R04
Human
Resource Costs
Maintenance
Costs
Per Annum
Per m3
Per Annum
Per m3
Per Annum
Per m3
Section V: Water Quality of Treated Water
V01
Treated water
turbidity
V02
Treated water pH
V03
V04
Treated water
Free Chlorine
Treated water
alkalinity
NTU
mg/l as Pt/Co / Hazen /
colour units
mg/l as CaCO3
95
Financial
Telemetric
V05
Treated water
conductivity
V06
Chemical
properties (mg/l)
V07
chlorophyll a
ug/l
V08
Treated water
DOC
mg/l
V09
Taste and odour
TON
V10
Temperature
V10
DO
V10
Other (specify)
Total Coliforms
(CFU/100 ml)
Fecal Coliforms
(CFU/100ml)
Standard Plate
Count (CFU/100
ml)
V11
V12
V13
mS/m
TDS
Iron
Fluoride
Manganese
Nitrate
Hardness
°C
Section W: Water Quality of Distribution System
W01
W02
W03
W04
W05
W06
W07
Sample Taken
From
Distribution water
turbidity
Distribution water
pH
Distribution water
Free Chlorine
Distribution water
alkalinity
Distribution water
conductivity
Shop
Garage
Clinic
Other
(specify)
NTU
mg/l as Pt/Co / Hazen /
colour units
mg/l as CaCO3
mS/m
TDS
Iron
W08
Chemical
properties (mg/l)
W09
chlorophyll a
ug/l
W10
Distribution water
DOC
mg/l
W11
Taste and odour
TON
W12
Temperature
W13
DO
W14
Other (specify)
Fluoride
°C
96
Manganese
Nitrate
Hardness
if available
Appendix 3.2
Water Treatment Processes and Equipment
The Disinfection processes and equipment used by the small water treatment plants in
Waterberg, Sekhukuni, Capricorn, Mopani, Vhembe (Limpopo Province) and Ehlanzeni,
Nkangala (Mpumalanga Province) Districts and local municipalities.
Mpumalanga
District
Municipality
(Local
Municipality)
Name of
Plants
(Owner type)
Water source
Treatment
processes
(Disinfection
practices)
Equipment
Lydenburg
(Municipality)
Surface water
Sabie
(Municipality)
Ground water
Coagulation,
Flocculation,
Stabilisation,
Sedimentation,
Filtration,
Chlorination
Chlorination
Sud floc
Open channel flocculators,
Lime
Circular settlers,
Rapid gravity sand filters,
Chlorine gas, Alldos pumps
Alldos pump
Nelspruit
(Private:
Biowater's)
Surface water
Coagulation,
Stabilisation,
Flocculation,
Sedimentation,
Filtration,
Chlorination
White river
(Municipality)
Surface water
Coagulation,
Flocculation,
Stabilisation,
Sedimentation,
Filtration,
Sudfloc
Lime
Open channel flocculators,
Circular settlers,
Rapid gravity sand filters,
Aldos pumps, Chlorine gas
Telemetric control panel,
Basic laboratory
instruments
Sudfloc,
Open channel flocculators,
Lime
Circular settling tanks,
Rapid gravity sand filters,
Pressure filters,
Chlorine gas,
Basic laboratory
instruments
Ferric chloride,
Static mixing
Lime
Circular settling tank
Pressure filters
HTH
Ferric chloride,
Open channel flocculators,
Soda ash,
Circular settling tanks,
Rapid gravity sand filters,
Aldos pumps, Chlorine gas
Basic laboratory
instruments
Ehlanzeni
(Thaba Chweu)
(Mbombela)
Chlorination
White river C E
(Municipality)
Surface water
Hazyview
(Municipality)
Surface water
Coagulation,
Flocculation,
Stabilisation,
Sedimentation,
Filtration,
Chlorination
Coagulation,
Flocculation,
Stabilisation,
Sedimentation,
Filtration,
Chlorination
97
Malelane
(Municipality)
Surface water
Coagulation,
Flocculation,
Stabilisation,
Sedimentation,
Filtration,
Chlorination
Matsulu
(Private:
Biowater's)
Surface water
Coagulation,
Flocculation,
Stabilisation,
Sedimentation,
Filtration,
Chlorination
Nka Nyamazane
re
(Municipality)
Surface water
Coagulation,
Flocculation,
Stabilisation,
Sedimentation,
Filtration,
Chlorination
Nka Nyamazane
old
(Municipality)
Surface water
Coagulation,
(Emalahleni)
Witbank
(Municipality)
Surface water
Coagulation,
Flocculation,
Stabilisation,
Sedimentation,
Filtration,
Chlorination
Sud floc,
Open channel flocculators,
LIME, Mechanic feeders,
Circular settling tanks,
Rapid gravity sand filters,
Aldoz pumps, Chlorine gas,
Telemetric control panel,
Basic laboratory equipment
(Highlands
local)
Belfast
(Municipality)
Surface water
Coagulation,
Flocculation,
Stabilisation,
Sedimentation,
Filtration,
Chlorination
Sud floc, Seiko pump
Open channel flocculators,
LIME, Mechanic feeder,
Horizontal settling tanks,
Rapid gravity sand filters,
Soni X100 pumps, Chlorine
gas, Telemetric control
panel,
Dullstroom
(Municipality)
Surface water
Coagulation,
Flocculation,
Stabilisation,
Sedimentation,
Filtration,
Chlorination
Polyelectrolyte,
Open channel flocculators,
LIME,
Horizontal settling tanks,
Rapid gravity sand filters,
HTH
Manual control
(Nkomazi)
Flocculation,
Stabilisation,
Sedimentation,
Filtration,
Chlorination
Sud floc 3450
Open channel flocculators,
Lime,
Horizontal settling tanks,
Rapid gravity sand filters,
TEKNA pumps, Chlorine
gas,
Sud floc 3450,
Open channel flocculators,
Lime,
Horizontal settling tanks,
Rapid gravity sand filters,
TEKNA pumps, Chlorine
gas, Telemetric control
panel
Sud floc 3450,
Open channel flocculators,
LIME
Horizontal settling tanks,
Rapid gravity sand filters,
Aldoz pumps, Chlorine gas,
Telemetric control panel,
Fully equipped laboratory
Sud floc 3450, PFINZTAL
DN632N.
Open channel flocculators,
LIME
Horizontal settling tanks,
Pressure filters,
Aldoz pumps, Chlorine gas,
Telemetric control panel,
Nkangala
98
Machadodorp
(Municipality)
Surface water
Coagulation,
Flocculation,
Stabilisation,
Sedimentation,
Filtration,
Chlorination
Sud floc 3456,
Open channel flocculators,
LIME,
Horizontal settling tanks,
Rapid gravity sand filters,
pumps, Chlorine gas,
Manual operation
Waterval Boven
(Municipality)
Surface water
Coagulation,
Polyelectrolyte U 3800,
TEKNA 400 pump,
Open channel flocculators,
LIME,
Horizontal settling tanks,
Rapid gravity sand filters,
TEKNA pump, Chlorine
gas,
Flocculation,
Stabilisation,
Sedimentation,
Filtration,
Chlorination
(Steve Tshwete
local)
Middelburg
(Municipality)
Surface water
Coagulation,
Flocculation,
Stabilisation,
Sedimentation,
Filtration,
Chlorination
Sud floc,
Open channel flocculators,
LIME,
Circular settling tanks,
Rapid gravity sand filters,
Prominent pumps, Chlorine
gas,
Kruger Dam
(Municipality)
Surface water
Coagulation,
Flocculation,
Stabilisation,
Sedimentation,
Filtration,
Chlorination
Sud floc,
Open channel flocculators,
LIME, Mechanic feeders,
Circular settling tanks,
Rapid gravity sand filters,
Aldoz pumps, Chlorine gas,
Telemetric control panel,
Presidentsrus
(Municipality)
Surface water
Coagulation
Flocculation,
Stabilisation,
Sedimentation,
Filtration,
Chlorination
Sud floc, HELDEL pump
Open channel flocculators,
LIME,
Circular settling tank,
Pressure filters,
HTH
Hendrina
(Municipality)
Surface water
Coagulation
Aluminium chloride, Milton
Roy pump
Open channel flocculators,
LIME,
Horizontal settling tank,
Rapid gravity sand filters,
Chlorine gas, Wallace and
Tierman pump
Flocculation,
Stabilisation,
Sedimentation,
Filtration,
Chlorination
99
Limpopo Province
Vhembe
district
Municipality
(Messina local)
Messina
(DWAF)
Coagulation
Surface water
Flocculation,
Stabilisation,
Sedimentation,
Filtration,
Chlorination
(Makhado)
Makhado
(Municipality)
Tshakhuma
Regional
(DWAF)
Tshakhuma
(DWAF,
BioWaters)
Tshedza
(DWAF)
Mutshedzi
(DWAF)
Tshifhire
(DWAF)
(Thulamela)
Vondo
(DWAF)
Coagulation
Flocculation,
Stabilisation,
Sedimentation,
Filtration,
Chlorination
Surface water
Coagulation
Surface water
Flocculation,
Stabilisation,
Sedimentation,
Filtration,
Chlorination
Coagulation
Flocculation,
Stabilisation,
Sedimentation,
Filtration,
Surface water
Surface water
Chlorination
Coagulation
Surface water
Flocculation,
Stabilisation,
Sedimentation,
Filtration,
Chlorination
Coagulation
Surface water
Flocculation,
Stabilisation,
Sedimentation,
Filtration,
Chlorination
Coagulation
Surface water
100
Aluminium sulphate ,
ALDOS pump
Open channel flocculator
Lime
Rapid gravity sand filters
Chlorine gas, HTH,
Polyelectrolyte, Milton Roy
pump
Lime
Open channel flocculator,
Rapid gravity sand filters
Chlorine gas
Ferric Floc HC 500,
ALDOS pump,
Open channel flocculators
Lime
Rapid gravity sand filters
Chlorine gas, HTH
Static mixer
Open channel flocculator
Lime
Rapid Gravity Sand Filters,
Pressure filters,
HTH, HYDROCARE pump
Polyelectrolyte,
HYDROCARE pump
Open channel flocculator
Soda ash
Horizontal settlers
Pressure filters
HTH
Aluminium sulphate,
ALDOS pump,
Pen channel flocculator
Lime
Flocculation,
Stabilisation,
Sedimentation,
Filtration,
Chlorination
Rapid Gravity Sand Filters
Chlorine gas and HTH
Polyelectrolyte, Hydrocare,
ALDOS pump
Static mixers
Soda ash
Horizontal settlers
Pressure filters
HTH
Coagulation
Flocculation,
Sedimentation,
Filtration,
Polyelectrolyte
Open channel flocculator
Horizontal settlers
Rapid gravity sand filters
Dzingahe
(DWAF)
Phiphidi
(DWAF)
Surface water
Chlorination
Coagulation
Surface water
Flocculation,
Stabilisation,
Sedimentation,
Filtration,
Chlorination
Coagulation
Flocculation,
Stabilisation
Sedimentation,
Filtration,
Chlorination
Damani
(DWAF)
Malamulele
(DWAF)
Coagulation
Flocculation,
Stabilisation
Sedimentation,
Filtration,
Chlorination
Coagulation
Surface water
Surface water
Flocculation,
Stabilisation
Sedimentation,
Filtration,
Chlorination
Mudaswali
(DWAF)
Surface water
Dzindi
(DWAF)
Surface water
Coagulation
Flocculation,
Stabilisation
Sedimentation,
Filtration,
Chlorination
Coagulation
Flocculation,
Stabilisation
Filtration,
Chlorination
Mhinga
(DWAF)
Coagulation
Surface water
Flocculation,
Stabilisation
Filtration,
Chlorination
Shikundu
(DWAF)
Coagulation
Surface water
Flocculation,
Stabilisation
Filtration,
Chlorination
101
Chlorine gas, HTH
Aluminium sulphate,
Syberg74 Rahier
Static mixers
Lime
Circular settling tank
Pressure filters
HTH
Polyelectrolyte, Hydro-care
AC 500, Milton Roy pump
Open channel flocculators
Lime
Horizontal settling tank
Rapid Gravity Sand Filters
Chlorine gas, HTH,
Wallace and Tierno pumps
Alu Floc,
Open channel flocculators
Lime
Rapid Gravity Sand filters
Chlorine gas, HTH
Ferric Floc HC 500,
ALDOS D76327
Open channel flocculators
Lime
Rapid Gravity Sand Filters
Chlorine gas, HTH,
CONTROL MATIC M20
pump
Telemetric control panel
Aluminium sulphate
Pipe flocculation
Lime
Circular settling tank
Pressure filters
HTH, SEIKO pump
Aluminium chloride,
DESAPRO MILTON ROY
pump
Static Mixers
Soda ash
Pressure filters
Chlorine gas, C103 GECO
ALLDOS
Polyelectrolyte
(Hydrocare), Milton Roy
G020 -611M pump
Static mixer
Soda ash
Pressure filters
Chlorine gas, HTH,
ALDOS C103 GECO
Polyelectrolyte,
HYDROCARE, ALDOS
S/NO2/16562
Open channel flocculators
Lime
Rapid Gravity Sand Filters
Chlorine gas, Chlorinator
Inc
(Mutale local)
Mutale
(DWAF,
Municipality)
Surface water
Tzaneen
(Municipality)
Surface water
Coagulation
Flocculation,
Stabilisation,
Sedimentation,
Filtration,
Chlorination
Polyelectrolyte, Hydrocare
CEP 153/39/NM
Open channel
Lime
Horizontal settlers
Slow sand filters
Chlorine gas, HTH
Mopani
district
(Greater
Tzaneen local)
George’s Valley
(Municipality)
Coagulation
Flocculation,
Stabilisation
Sedimentation,
Filtration,
Chlorination
Coagulation
Flocculation,
Stabilisation
Sedimentation,
Filtration,
Chlorination
Coagulation
Flocculation,
Stabilisation
Sedimentation,
Filtration,
Chlorination
Surface water
Nkowankowa
(DWAF)
Surface water
Semerela
(DWAF)
Surface water
Coagulation
Flocculation,
Stabilisation
Sedimentation,
Filtration,
Chlorination
Thapane
(DWAF)
Surface water
Coagulation
Flocculation,
Stabilisation
Sedimentation,
Filtration,
Chlorination
Nkambako
(DWAF)
Surface water
Letsetele
(Municipality)
Surface water
Coagulation
Flocculation,
Stabilisation
Sedimentation,
Filtration,
Chlorination
Coagulation
Flocculation,
Stabilisation
Sedimentation,
102
Ferri floc
Open channel floculators
Lime
Rapid sand filters
Chlorine gas, HTH
Ferri floc, Seiko pump
Open channel flocculators
Lime
Rapid Gravity Sand filters
Chlorine gas
Polyfloc, Encore 100 Pump
Open channel flocculator
Lime
Horizontal settling tanks
Rapid gravity sand filters
Chlorine gas, HTH,
Wallace and Tienan pump
Poly Floc, ENCORE 100
pump, Static mixer
Open channel flocculators
Soda ash
Horizontal settlers
Pressure filters
Chlorine gas, HTH,
Wallace and Tienan pump
Telemetric control panel
Poly Floc, ENCORE 100
PUMP,
Open channel floculators
Soda ash
Horizontal settlers
Rapid gravity sand filters
Chlorine gas, HTH,
Wallace and Tienan pump
Poly Floc, ALDOS pump
Open channel flocculators
Lime
Horizontal settlers
Rapid gravity sand filters
Chlorine gas, HTH
Aluminium sulphate,
ALDOS pump
Open channel flocculators,
Lime
Horizontal settlers
Capricorn
(Polokwane
Filtration,
Chlorination
Rapid gravity sand filters
Chlorine gas, HTH
Pietersburg
(Polokwane
Municipality)
Surface water
Coagulation
Flocculation,
Sedimentation,
Filtration,
Chlorination
Seshego
(Municipality)
Surface water
Maratapilu
(DWAF)
Surface water
Coagulation
Flocculation,
Sedimentation,
Filtration,
Chlorination
Coagulation
Flocculation,
Sedimentation,
Filtration,
Chlorination
Poly, ELATRON pump,
Open channel flocculation,
Horizontal settling tanks
Rapid gravity sand filter,
Chlorine gas, WALLACE
and TIENAN pump
Poly, Prominent pump
Open channel flocculators
Horizontal settling tanks
Rapid gravity sand filters
Chlorine gas, HTH
Polyelectrolyte
Open channel flocculators,
Horizontal settling tanks
Slow sand filters
HTH
(Modimole
local)
Nylstroom:
Modimole
(Municipality)
Surface water
Coagulation
Flocculation,
Stabilisation,
Sedimentation,
Filtration,
Chlorination
Ferric floc, Prominent pump
Open channel flocculators,
LIME,
Horizontal settling tank,
Rapid gravity sand filters,
HTH,
(Bela Bela local)
Bela Bela
(Municipality)
Surface water
Coagulation
Flocculation,
Stabilisation,
Sedimentation,
Ferric floc, Prominent pump
Open channel flocculators,
LIME,
Horizontal settling tank,
Circular settling tank
Rapid gravity sand filters,
HTH, Cartridge filling,
ECO JET 130 pump
local)
Waterberg
Filtration,
Chlorination
(Mogalakwena
local)
Potgietersrus
(Mokopane)
Surface water
(Thabazimbi
local)
Thabazimbi
(Municipality)
Surface water and
ground water
Chlorination
Chlorine gas, Prominent
pump
(Mookgopong
local)
Naboomspruit
(Municipality)
Surface water
Coagulation
Flocculation,
Stabilisation,
Sedimentation,
Filtration,
Chlorination
Polyelectrolyte, ASA Water
pump
Open channel flocculator,
Lime, mechanic feeder,
Horizontal settling tanks
Slow sand filters
Chlorine gas, Wallace and
Tienan pump
Burgersfort
(Municipality)
Surface water
Coagulation
Flocculation,
Ferri Floc, SECO pump
Pipe flocculator
Sekhukuni
District
(Greater tubatse
local)
103
Sedimentation,
Filtration,
Chlorination
Coagulation
Tubatse
(Praktiseer)
(Municipality)
Surface water
Ohrigstad
(Municipality)
Steelpoort
(Municipality)
Ground water
Chlorination
Chlorination
Ground water
No treatment
Flocculation,
Sedimentation,
Filtration,
104
Horizontal settling tanks
Rapid gravity sand filters
Chlorine gas, Wallace and
Tienan pump
Aluminium Chloride,
Milton Roy pump
Open channel flocculators
Horizontal settling tanks,
Rapid gravity sand filters,
Slow sand filters
Chorine gas, Choroquip
HTH, SERA C21 pump
Plant
Water source
North West Province.
Disinfection
Equipment
practices
Bloemhof
Surface water-river
Coagulation
Surface water-river
Flocculation
Sedimentation
Filtration
Chlorination
Pre-chlorination
Christiana
Aquafloc 1090&3070
ALLDOS pump and Kemix mixer systems
Circular scraper clarifier
Coagulation
Pudumong
Surface water-river
Dissolved Air
Flotation
Sedimentation
Filtration
Chlorination
Coagulation
Slow sand filters
Chlorine gas, ALLDOS oxygraph 304 pump
Chlorine gas ALLDOS pump
Powdered Activated Carbon &ALLDOS Premus
serie pump
DAF system
Horizontal settling tanks
Slow sand filters
Chlorine gas &ALLDOS pump
Aluminium chloride & ALLDOS Primus serie
pump
Open channel flocculator
Flocculation
SchweizerReneke
Lichtenburg
Groot Mariko
Surface water-dam
Ground waterboreholes
Surface water-river
Sedimentation
Filtration
Chlorination
Coagulation
Flocculation
Sedimentation
Dissolved Air
Flotation
Filtration
Chlorination
Chlorination
Solid removal
Coagulation
Circular scraper clarifier
Slow sand filters
Chlorine gas - AllDOS
Sud-floc3TL & ALLDOS pump
Open channel flocculators
Horizontal settling tanks
DAF system
Slow sand filters
Chlorine gas& ALLDOS pump
Chlorine gas & ALLDOS primus serie pump
Leave strainer
Sudfloc3484 & ALLDOS pumps
Soda ash and dry chemical feeder
pH stablisation
Flocculation
Sedimentation
Filtration
Chlorination
Pela
Surface water-dam
Coagulation
pH stabilization
Flocculation
Sedimentation
Chlorination
Filtration
105
Pipe flocculation system
Upflow settlers
Pressure filters
Chlorine gas & S10K Wallace and Terran pump
Aluminium sulphate and ultrafloc 5082, ALLDOS
primus serie pumps
Soda ash
Pipe flocculation system
Cyclone clarifiers
Granular HTH & ALLDOS pump
Rapid sand filters
Madikwe
Surface water -dam
Coagulation
pH stabilisation
Flocculation
Sedimentation
Chlorination
Mmabatho
Surface water-dam
Filtration
Solid removal
Coagulation
pH stabilisation
Mafikeng
Itsoseng
Koster
Swartruggens
Ground waterboreholes and springs
Ground waterboreholes
Surface water –dam
and ground waterboreholes
Surface water-dam
Surface water-river
DAF system
Rapid sand filters
Chlorine gas & ALLDOS pumps
Coagulation
Ultrafloc & ALLDOS pump
Hydraulic (Open channel) flocculators
Horizontal settling tanks
Rapid sand filters
Chlorine gas & ALLDOS pump
Flocculation
Sedimentation
Filtration
Chlorination
Coagulation
Flocculation
Sedimentation
Filtration
Chlorination
Coagulation
Flocculation
Dissolved Air
Flotation
Sedimentation
Filtration
Chlorination
Hartbeespoort
Surface water - dam
Ventersdorp
Ground water- spring
Potchefstroom
Surface water - dam
Leave strainer
Ferric chloride and ALLDOS pump
Soda ash-dry chemical feeders
Circular scraper clarifier
Flocculation and
sedimentation
Dissolved Air
Flotation
Filtration
Chlorination
Screening
Filtration
Chlorination
Chlorination
pH stabilization
Madibeng
Calcium chloride and ultra-floc – ALLDOS pumps
Soda ash
Pipe flocculation system
Upflow settlers
Granular HTH – ALLDOS pump
Pressure filters
Coagulation
Flocculation
Dissolved Air flotation
Filtration
Chlorination
Filtration
Chlorination
Coagulation
106
Pressure filters
Chlorine gas and ALLDOS pumps
Chlorine gas and ALLDOS pumps
Ferric chloride and ALLDOS pump
Lime and dry chemical feeders
Pulsators
Horizontal settling tanks
Pressure filters
Sodium hypochlorite& ALLDOS pumps
Aluminium chloride U3400, Plaestol 611BC and
Powdered Activated carbon- ALLDOS pumps
Open channel flocculators
DAF system
Pulsator Clarifiers
Rapid sand filters
Chlorine gas –ALLDOS pump
Aluminium chloride-U3500 and Powdered
Activated carbon- ALLDOS dosing pump
Open Channel Flocculators
DAF system
Rapid sand filters
Chlorine gas –Regal dosing pumps
Slow sand filters
Chlorine gas- Hydrogas chlorinator
Ferric chloride- ALLDOS pump
Flocculation
Chlorination
Sedimentation
Filtration
Chlorination
107
Open channel flocculators
Chlorine gas- ALLDOS pump
Circular scraper clarifiers
Rapid gravity sand filters
Chlorine gas-ALLDOS pump
Free State Province
Local
Municipality
Plants
Water source
Disinfection
practices
Equipment
HarrismithWilge Plant
Wilge River
Botanical
plant
Dam and Wilge
River
Phumelela
Warden
Dam
Phumelela
Memel
Dam
Coagulation,
Flocculation,
Sedimentation,
Filtration,
Chlorination
pH correction
Coagulation,
Flocculation,
Sedimentation,
Filtration,
Chlorination
pH correction
Coagulation,
Flocculation,
Sedimentation,
Filtration,
Chlorination
pH correction
Coagulation,
Flocculation,
Sedimentation,
Filtration,
Chlorination
Villiers
River
Polyelectrolyte
Open channel flocculation,
Horizontal flow clarifiers,
Rapid gravity sand filters,
Chlorine gas, dosing pump
Dry lime feeder
Polyelectrolyte
Flocculation in clarifier,
Radial flow clarifier,
Rapid gravity sand filters,
Chlorine gas, dosing pump
Dry lime feeder
Polyelectrolyte
Open channel flocculation,
Horizontal flow clarifier,
Rapid gravity sand filters,
Chlorine gas, dosing pump
Dry lime feeder
Polyelectrolyte
Open channel flocculation,
Vertical flow clarifier,
Dual media pressure filters,
Chlorine gas, Alldos
chlorinator
Polyelectrolyte (Prominent
pumps)
Open channel flocculation,
Horizontal and vertical flow
clarifiers,
Rapid gravity sand and
pressure filters,
Ecometric gas chloronator,
Dry lime feeder
Polyelectrolyte (ACL
pump)
Open channel flocculation,
Radial flow clarifier,
Rapid gravity sand filters,
Wallace and Tienan gas
chlorinator
Dry lime feeder
Polyelectrolyte (Alldos
pumps)
Open channel flocculation,
Horizontal flow clarifiers,
Rapid gravity sand filters,
Ecometric gas chloronator,
Dry lime feeder
Polyelectrolyte (Alldos
pump)
Pipe flocculation,
Vertical flow clarifier,
Dual media pressure filters,
Maluti-A-Phofung
Coagulation,
Flocculation,
Sedimentation,
Filtration,
Mafube
Metsimaholo
Chlorination
pH correction
Coagulation,
Flocculation,
Sedimentation,
Filtration,
Chlorination
pH correction
Tweeling
River
Frankfort
River
Coagulation,
Flocculation,
Sedimentation,
Filtration,
Chlorination
pH correction
Oranjeville
Dam
Coagulation,
Flocculation,
Sedimentation,
Filtration,
Chlorination
108
pH correction
Ngwathhe
Parys
River
Koppies -
River
Vredefort -
River
Pre-chlorination
Coagulation
Flocculation
Sedimentation
Filtration
Chlorination
pH correction
Coagulation
Flocculation
Sedimentation
Filtration
Chlorination
Edenville
Coagulation,
Flocculation,
Sedimentation,
Filtration,
Chlorination
Borehole
Disinfection
109
Calcium, hypoChlorite gas;
Alldos pump
Soda ash; Alldos pump
Sodium hypochlorite pump
Ployeletrolyte (Alldos
pump)
Flocculation in clarifiers,
Radial flow clarifier,
Rapid gravity sand filters,
Sodium hypochlorite pump
Dry lime feeder
Polyelectrolyte (Alldos
pump)
Open channel flocculation,
Horizontal and vertical flow
clarifiers,
Rapid gravity sand filters,
Sodium hypochlorite pump,
Alldos pump
Polyelectrolyte (pump)
Open channel flocculation,
Horizontal flow clarifiers,
Rapid gravity sand filters,
Sodium hypochlorite Alldos
pump
Sodium hypochlorite
chemical pump
Plant
KwaZulu- Natal
Water source
Disinfection practices
Equipment
Assegaai
Belgrade
Bethesda (umkuze)
Ceza
Enyokeni
Frischgewaagd
Greytown
Hlanganani
Hlokozi
Itshelejuba
Ixopo
Jozini
Kwazibusele
Manguzi
Pongola River
Belgrade Dam
Umkuze River
Vungu River
Usuthu Spring
Pongola River
Merthley Lake & Spring
No info
No info
Borehole
Sodbux Dam
Jozini Dam
Kwazibusele Borehole
Shengeza River/Gezisa
Spring/Borehole
Chlorination (Sodium hypo)
Chlorination (Sodium hypo)
Chlorination (Sodium hypo)
Chlorination (Sodium hypo)
Chlorination (Sodium hypo)
Chlorination (Sodium hypo)
Chlorination (gaseous Cl2)
No info
No info
Chlorination (Sodium hypo)
Chlorination (gaseous Cl2)
Chlorination (gaseous Cl2)
No info
Chlorination (Sodium hypo)
1 Dosing pump
2 Dosing pumps
1 Dosing pump
1 Dosing pump
1 Dosing pump
1 Dosing pump
1 Chlorinator & Injector
No info
No info
1 Dosing pump
1 Chlorinator & Injector
1 Chlorinator & Injector
No info
1 Dosing pump
Mbazwana
Middeldrift
Mpungamhlophe
Mseleni
Mtwalume
Nongoma
Pongola
Richmond
Thulasizwe
Hospital
Tongaat Hullet
Ulundi
Sibaya Lake
Tugela River
White Umfolozi River
Sibaya Lake
Mtwalume River
Vuna Dam
Pongola River
River/Spring
Sikhulule River
Chlorination (Sodium hypo)
Chlorination (Sodium hypo)
Chlorination (Sodium hypo)
Chlorination (Sodium hypo)
Chlorination (gaseous Cl2)
Chlorination (gaseous Cl2)
Chlorination (Sodium hypo)
Chlorination (gaseous Cl2)
Chlorination (Sodium hypo)
1 Dosing pump
2 Dosing pump
1 Dosing pump
1 Dosing pump
1 Chlorinator & Injector
1 Chlorinator & Injector
1 Dosing pump
1 Chlorinator & Injector
1 Dosing pump
Tongaat & Emone Rivers
Ulundi weir (on White Umfolozi
River)
No info
No info
No info
No info
Chlorination (gaseous Cl2)
No info
1 Chlorinator & Injector
Chlorination (gaseous Cl2)
Chlorination (Sodium hypo)
Chlorine dioxide
No info
Dosing pump
Dosing pump
Umbumbulu
Vulamehlo
Wild Coast
110
Eastern Cape Province
District
Municipality
Cacadu
Name of
Plants
(Owner type)
Water source
Treatment
processes
(Disinfection
practices)
Equipment
Graaff -Reinet
Ground water and
Surface water
Coagulation,
Flocculation,
Sedimentation,
Filtration,
Chlorination
Aberdeen
Groundwater
Willowmore
Ground water
ChlorinationSodium hypochlorite
Coagulation,
Sud floc
Open channel flocculators,
Horizontal settlers,
Rapid gravity sand filters,
Chlorine gas,
Chlorochol 14383 dosing
pumps
Hypochlorite dosing pumps
- HPVM
Sud floc 3450 & Lime
UMP model 1620
Open channel flocculators,
Horizontal settling tank,
Slow sand filters
ALLDOS pumps
Flocculation,
Sedimentation,
Filtration,
Chlorination
Pearston
Ground water
Chlorination
Somerset East
Surface water
Coagulation,
Flocculation,
Sedimentation,
Chlorination
Cookhouse
Coagulation,
Surface water
Sedimentation,
Filtration,
Chlorination
Joubertina
Coagulation,
Surface water
pH Adjustment
Flocculation,
Stabilisation,
Sedimentation,
Filtration,
Chlorination
Louterwater
Surface water
Kareedouw
Surface water
Hankey
Surface water and
ground water
111
Filtration,
Chlorination
Pre-Filtration,
Secondary filtration
Chlorination
Coagulation,
Flocculation,
Sodium Hypochlorite,
Electrical pumps for
abstraction
Ultrafloc 3500, Milton Roy
dosing pump- CEG020515H
Open channel flocculators,
Upflow Settlers,
Chlorine gas, ALLDOS
pump
Ultrafloc 3500, POMPA
dosing POMPA HPVM
1004 FP
230 VAC
Open rapid sand filters,
ALLDOS pump
Telemetry system employed
Powdered activated carbon
dosed by ALLDOS pump
and Lime dosed dry
chemical feeders
Open channel flocculators,
Circular scrapper settlers
Pressure filters
Chlorine gas,
Ecometrics stries 480 pump
Pressure filters
HTH- hypochlorite filters
Lime stone filters,
Pressure filters
Sud Ultrafloc 3500
Open channel flocculators,
Sedimentation,
Filtration,
Chlorination
pH stabilization
Patensie
Surface water and
ground water
Coagulation,
Chlorination
Flocculation,
Sedimentation,
pH stabilization
Filtration
Humansdorp
Jeffreys bay
Coagulation and pH
stabilization
Flocculation,
Sedimentation,
Filtration
Chlorination
Pre-treatment- Solid
removal
Chlorination
Ozonation and pH
Stabilization
Filtration
Ozonation
Coagulation,
Flocculation,
Sedimentation,
Chlorination
Filtration
Ground water
Bathurst
Surface water
Port Alfred
Surface water
Coagulation,
Flocculation,
Sedimentation,
Filtration,
Chlorination
Sea Field
Surface water
Coagulation,
Albany water
board
Amathole
Surface water and
ground water
Idutywa
Elliotdale
Sedimentation,
Chlorination
Filtration
Coagulation and pH
Stabilisation,
Flocculation,
Sedimentation,
Filtration,
Chlorination
Surface water
Coagulation and pH
Stabilisation,
Flocculation,
Sedimentation,
Filtration,
Chlorination
Surface water
Coagulation,
Chlorination
Surface water
112
Horizontal settling tanks,
Rapid g sand filtersvalveless,
ALLDOS pumps
Lime,
Polyelectrolyte and
ALLDOS coagulant dosing
pump
ALLDOS pumps
Open Channel
Horizontal settlers
Lime
Conventional Sand filters
Alum and Lime
Open Channel flocculators
Horizontal settlers
Slow sand filters
Conventional Sand filters
Filtration with net
ALDOS pump, Ozone
generator and caustic
Soda
Pressure Filters
Ozone generator
Ferifloc 820- ALLDOS
pump
Pipe flocculation
Horizontal settlers
ALLDOS pump
Pressure Filters
Ferifloc 820- ALLDOS
pump
Open channel flocculators
Horizontal settlers
Slow sand filters
HTH
Ferrifloc-Microprecessor
dosing pump
ALLDOS pump
Pressure filters
Alum and Soda ash
Open channel
Horizontal settlers
Rapid sand filters-valveless
HTH and HTH dosing
pumps
Alum and Soda ash
Open channel
Horizontal settlers
Rapid sand filters-valveless
HTH and HTH dosing
pumps
Alum
HTH and HTH dosing
Butterworth
Surface water
Flocculation,
Sedimentation,
Filtration,
pumps
Open channel flocculator
Horizontal settlers
Slow sand filter
Coagulation,
Alum and Primco 735
dosed by dry screw feeder
and Prominent dosing pump
Upflow settlers
Rapid sand filters
Advanced seventrew series
capital contracts Model 480,
chlorine gas
Profloc 150, ALLDOS
P150 pump
Pipe flocculation
Horizontal settler
(swimming pool)
Pressure filters
HTH, CMSIC pulse meter
Diomite filters
HTH and Milton Roy
CEP053
HTH and Siemens dosing
pump
Sudfloc 3890 & 475 and
Milton Roy A 952-86
Circular settling tanks
Pressure filters
Sodium hypochlorite
generated onsite
Sud floc 3899, and
ALLDOS 205
Sedimentation,
Filtration,
Chlorination
Cintsa
Coagulation,
Surface water
Flocculation,
Sedimentation,
Kei Mouth
Surface water
Morgans Bay
Surface water
Filtration,
Chlorination
Filtration,
Chlorination
Prechlorination
Coagulation,
Sedimentation,
Filtration,
Chlorination
Hagahaga
Pre-Sedimentation,
Coagulation
Flocculation,
Sedimentation,
Filtration,
Chlorination
Surface water
Komga
Surface water
Cathcart
Surface water
Pre-Sedimentation,
Coagulation and pH
stabilization
Flocculation,
Sedimentation,
Disinfection
Coagulation
Flocculation,
Sedimentation,
Filtration,
Disinfection
Adelaide
Coagulation
Surface water
Flocculation,
Sedimentation,
Filtration,
Chlorination
113
Pipe flocculators,
Radial flow settlers,
Pressure filters,
HTH and CMSIC pulse
meter
Radial flow settlers,
Alum and soda ash – dry
chemical feeders
Open channel flocculator
Radial flow settlers,
HTH
Sud floc 3880, and Concept
plus pump CNPA0704
Open channel flocculator
Horizontal settling tanks
Rapid gravity sand filters
Chlorine gas and Hydrogas
pump
Sud floc 3456, and
ALLDOS pump
Open channel flocculator
Horizontal settlers
Rapid gravity sand filters
Chlorine gas and ALLDOS
pump
Bedford
Surface water and
ground water
Coagulation
Flocculation,
Sedimentation,
Filtration,
Chlorination
Chris Hani
Cradock
Coagulation
Surface water
Flocculation,
Sedimentation,
Filtration,
Chlorination
Queenstown
Coagulation
Surface water
Flocculation,
Sedimentation,
Chlorination
Sada
Coagulation
Surface water
Flocculation,
Sedimentation,
Filtration,
Chlorination
Cofimvaba
Coagulation
Surface water
Flocculation,
Sedimentation,
Filtration,
Chlorination
Dordrecht
Surface water
Coagulation
Flocculation,
Sedimentation,
Filtration,
Chlorination
Macubeni
Surface water
Coagulation
Flocculation,
Sedimentation,
Filtration,
Chlorination
pH stabilization
Ngcobo
Coagulation
Surface water
Flocculation,
Sedimentation,
Filtration,
Chlorination
All saints hospital
Coagulation and pH
Surface water
114
Zetafloc A100 Etatran DS
dosing pump
Open channel
Horizontal flow settlers
Rapid gravity sand filters
Sodium hypochlorite and
CMSIC pulse meter
Sud floc 3456, and
ALLDOS pump
Pipe flocculation
Vertical flow sedimentation
tanks
Rapid gravity sand filters
Chlorine gas and advance
chlorinator 480
Primco 735 and ALLDOS
dosing pump
Open channel flocculation
Horizontal settlers
Chlorine gas sucked by the
propeller
Polyfloc 5075 and
Promonent dosing pump
Open channel flocculation
Horizontal settling tanks
Rapid sand filters
Chlorine gas -ALLDOS
pump
Ultrafloc 3100 and
ALLDOS dosing pump
Pipe flocculation,
Radial flow settlers,
Rapid valveless sand filters
HTH- ALLDOS dosing
pump
P101 and ALLDOS dosing
pump
Open channel flocculation
Upflow settlers
Rapid Gravity Sand Filters
Chlorine gas and advances
chlorinator
Ultrafloc500 Prominent
dosing pump
Open channel flocculation
Horizontal settlers
Pressure filters
Chlorine gas and ALLDOS
pump
Lime
Polyelectrolyte (unknown)ALLDOS pump
Pipe flocculation
Horizontal and Upflow
settlers
Rapid Sand Filtersvalveless
HTH- ALLDOS dosing
pump
Alum and lime. Alum dosed
adjustment
Molteno
Flocculation,
Sedimentation,
Filtration,
Chlorination
Coagulation
Flocculation,
Sedimentation,
Filtration,
by constant level feeder and
lime by dry feeder
Open channel flocculators
Horizontal
Pressure filters
HTH level feeder
Ultrafloc. Prominent dosing
system
Mechanical stirrer
Vertical flow sedimentional
tanks
Rapid Sand Filtersvalveless
Chlorine gas and ALLDOS
dosing pump
M7005 NS ALLDOS pump
Open channel flocculation
Horizontal and Upflow
settlers
Pressure Filters
Chlorine gas and ALLDOS
dosing pump
M7005 NS ALLDOS pump
Pipe flocculation
Upflow settlers
Pressure Filters
Chlorine gas and ALLDOS
dosing pump
Horizontal settlers
Chlorine gas and ALLDOS
dosing pump
Pressure Filters
Flocculation,
Sedimentation,
Filtration,
Chlorination
Coagulation
Surface water
Flocculation,
Sedimentation,
Filtration,
Chlorination
Ukwakhahlamba
Maclear
Surface water
Coagulation
Flocculation,
Sedimentation,
Filtration,
Chlorination
Sonwabile
Surface water
Coagulation
Ugie
Surface water
Lady Grey
Surface water
Coagulation
Flocculation,
Sedimentation
Filtration,
Sudfloc 3860, ALLDOS
Pipe flocculation
Upflow settlers
Pressure Filters
Aliwal North
Surface water
Coagulation
Ultrafloc 5100 and
ALLDOS dosing pump
Open channel flocculation,
Horizontal settlers and
Radial flow,
Slow sand filters and
pressure filters
Chlorine gas and ALLDOS
dosing pump
Profloc 3860, ALLDOS
Open channel
Horizontal settlers
Rapid gravity sand filters
Chlorine gas and ALLDOS
dosing pump
Profloc 3860, ALLDOS
Open channel flocculation
Horizontal
Pressure Filters
HTH dosed manually
Ultrafloc, ALLDOS pump
Flocculation,
Sedimentation,
Filtration,
Chlorination
Burgersdorp
Surface water
Coagulation
Flocculation,
Sedimentation,
Filtration,
Chlorination
Barkley East
Surface water
Elliot
Surface water
Coagulation
Flocculation,
Sedimentation,
Filtration,
Chlorination
Coagulation and pH
Stabilisation
115
OR Tambo
Umtata
Flocculation,
Sedimentation,
Filtration,
Chlorination
Coagulation and pH
Stabilisation
Surface water
Flocculation,
Sedimentation,
Mqanduli
Surface water
Tsolo
Surface water
Ngqeleni
Surface water
Filtration,
Chlorination
Coagulation and pH
Stabilisation
Flocculation,
Sedimentation,
Filtration,
Chlorination
Coagulation and pH
Stabilisation
Flocculation,
Sedimentation,
Filtration,
Chlorination
Coagulation and pH
Stabilisation
Flocculation,
Sedimentation,
Chlorination
Lutsheko
Surface water
Coagulation and pH
Stabilisation
Flocculation,
Sedimentation,
Chlorination
Libode
Surface water
Coagulation
Flocculation,
Sedimentation,
Filtration,
Chlorination
Umzimvibu
Coagulation
Surface water
Flocculation,
Stabilisation
Sedimentation,
Filtration,
Chlorination
Bulolo
Coagulation and pH
Stabilisation
Flocculation,
Sedimentation,
Chlorination
Surface water
116
Open channel floculators
Horizontal settlers
Rapid valveless sand filters
Chlorine gas and ALLDOS
Zetafloc LP226 and Lime
dosed by ALLDOS pump
and dry chemical feeders
Open channel floculators
Upflow settlers
Diatomceous filter and
Rapid Gravity Sand filters
Chlorine gas and ALLDOS
Alum and Soda ash dosed
by manually
Open channel flocculation
Horizontal setters
Slow Sand filters
HTH dosed manually
Sudfloc and Soda ash dosed
by CMSIC pulse meter
Open channel flocculation
Horizontal settlers
Pressure filters
HTH dosed by CMSIC
pulse meter
Alum and Lime dosed
manually
Open channel flocculation
Horizontal settlers
HTH dosed manually
Zetafloc LP226 ALLDOS
pump
Open channel floculators
Upflow settlers
Diatomceous filter and
Rapid
Chlorine gas and ALLDOS
Polyelectriolyte (Not
known) dosed by prominent
pump
Open channel flocculators
Horizontal settlers
Slow sand filters
Bromine tablets (potabrom)
Polyelectriolyte (Not
known) dosed by prominent
pump
Open channel flocculators
Upflow settlers
Pressure filters
HTH dosed by ALLDOS
pump
Profloc 3890, and lime
dosed
Open channel flocculation
Upflow settlers
Rapid gravity sand filters
Chlorine gas
Mt Ayliff
Surface water
Mt Frere
Surface water
Chlorination,
Coagulation and pH
Stabilisation
Sedimentation,
Filtration
Screening
Coagulation and pH
Stabilisation
Flocculation,
Sedimentation,
Filtration,
Chlorination
117
HTH, Alum and lime dosed
manually
Radial settlers
Rapid valveless sand filters
Polyfloc 5015 dosed by
prominent dosing pump and
lime
Open channel flocculator,
Horizontal settlers
Rapid conventional filters
Chlorine gas.
Western Cape Province
Local
Municipality
(Owner)
Plettenberg Bay
Knysna
Name of
Plants
Water source
Plettenberg
Bay
Surface water
(river and Dam)
Rheenendal
Surface water
Knysna
Surface water
(river and Dam)
Ruigter
Surface water
Treatment
Process
Disinfection
practices
Coagulation,
Flocculation,
Sedimentation,
Flotation,
Filtration,
Disinfection
Stabilization
Coagulation,
Flocculation,
Sedimentation,
Filtration,
Disinfection
Coagulation,
Flocculation,
Sedimentation,
Filtration,
Disinfection
Stabilization
Coagulation,
Flocculation,
Stabilization
Sedimentation,
Filtration,
Disinfection
George
George
Surface water (Dam)
Coagulation,
Flocculation,
Sedimentation,
Filtration,
Disinfection
Stabilization
Mossel Bay
Wilderness
Surface water
(River)
Klein Brak
River
Surface water (Dam)
Great Brak
River
Surface water (Dam)
118
Coagulation,
Flocculation,
Sedimentation,
Filtration,
Disinfection
Stabilization
Coagulation,
Flocculation,
Sedimentation,
Filtration,
Disinfection
Stabilization
Coagulation,
Flocculation,
Sedimentation,
Equipment
Alum (ALLDOS) and PAC
Open channel flocculation,
Horizontal settlers,
DAF
Rapid gravity sand filters,
Chlorine gas, ALLDOS
lime (Dry chemical feeders)
Alum (ALLDOS)
Open channel flocculation,
Horizontal
Gravity sand
Chlorine gas ALLDOS
Alum, Gravity feed
Open channel flocculation,
Horizontal
Gravity sand
Chlorine gas ALLDOS
Lime
(Alum and Polyelectrolyte)
Milton Roy Series GTM
Open channel flocculation,
Lime
Horizontal settlers
Pressure filters and rapid
sand filters
Chlorine gas and ALLDOS
Ferric Chloride (ALLDOS)
Polyelectrolyte
Open channel flocculation,
Horizontal
Rapid sand filters,
Horizontal
Chlorine gas,(Wallace and
Tienan, regulator)
Lime
Alum (ALLDOS)
Pipe flocculation,
Horizontal
Rapid sand
Chlorine gas ALLDOS
Soda Ash
Alum (ALLDOS)
Open channel flocculation,
Horizontal
Rapid sand filters,
Chlorine gas, Venture
system
Lime (Marlin and Watson)
Alum (ALLDOS)
Open channel flocculation,
Horizontal
Filtration,
Disinfection
Stabilization
Sandhoogte
Surface water (Dam)
Coagulation,
Flocculation,
Sedimentation,
Filtration,
Disinfection
Stabilization
Fremersheim
Surface water (Dam)
Coagulation,
Flocculation,
Sedimentation,
Filtration,
Disinfection
Stabilization
Langeberg
Riversdale
Surface water (Dam)
Albertinia
Ground water
(Borehole)
Still Bay
Ground water
119
Coagulation,
Flocculation,
Sedimentation,
Filtration,
Disinfection
Stabilization
Coagulation,
Flocculation,
Sedimentation,
Filtration,
Disinfection
Stabilization
Coagulation,
Filtration,
Disinfection
Rapid sand filters,
Chlorine gas (Venture
system)
Lime
Alum (ALLDOS)
Open channel flocculation,
Horizontal
Rapid sand filters,
Chlorine gas, Venture
system
Lime (Marlin and Watson)
Ultrafloc 3800 (Milton roy
CEP043-531NM)
Open channel Flocculation
Upflow settlers
Pressure filters
Sodium hypochlorite
(ALLDOS)
Soda Ash
Alum (ALLDOS)
Open channel flocculation,
Horizontal
Slow sand
Chlorine gas (ALLDOS)
Lime and Soda Ash
Alum
Pipe flocculation,
Upflow
Upflow
Chlorine gas (ALLDOS)
Soda Ash
Ultrafloc 3500 (Poly)
Siemens
Pressure
Ozonation
Malelane
Matsulu
KaNyamazane
regional
KaNyamazane
old plant
Sabie
White river
regional
White river
Country estate
Nelspruit
Hazyview
Lydenburg
Plant
Final
0.82
0.7
1.77
10.9
0.18
0.82
0.32
1.56
7.15
1.81
Raw
28.5
26
87.4
86.7
0.19
10.09
3.17
53.7
18.6
2.88
0.79
0.62
1.33
0.37
0.17
0.21
4.13
POU
0.61
1.3
2.41
Turbidity (NTU)
16.4.5
10.3.2
50.0
60.2
20.4
5.6
21.4
Raw
31.2
25.0
27.8
18.0
11.5
52.1
92.1
18.4
9.1
28.6
Final
32.2
33.1
24.4
20.5
12.8
52.5
167.2
16.7
8.5
27.1
POU
35.3
34.5
24.6
Conductivity (PS/m)
120
7.89
8.05
7.98
6.9
8.00
8.13
7.96
Raw
8.06
8.05
7.94
8.1
7.62
7.30
9.1
7.81
9.37
7.94
Final
7.83
7.53
8.06
pH
8.03
7.77
7.81
7.84
7.76
7.63
8.07
POU
7.93
7.82
8.29
19.2
23.3
15.4
20.8
17.2
21.5
25.3
Raw
25
26.3
25.4
22.3
25.4
15.6
21.4
19.4
21.1
24.2
Final
27.1
27.7
26.2
24.2
24.4
16.0
23.4
20.1
25.2
22.3
POU
25.3
31.1
25.7
Temperature (oC)
Ehlanzeni district Municipality
Mpumalanga Province
0.38
0.68
2.13
0.16
0.25
1.4
1.6
0.46
4
3.36
Chlorine
dosage
(mg/l)
62
3.09
6
2
5.6
6
10
26
12
57
Current
flow
(Ml/D)
0.35
0.50
2.12
0.14
0.24
1.32
1.65
0.15
0.48
0.23
0.10
0.18
0.51
0.14
Residual
Chlorine
(mg/l)
Final POU
0.27
0.21
2.48
0.51
1.75
0.59
Physico-chemical Quality of Raw Water and Treated Drinking Water in Various Surveyed
Plants
Appendix 3.3
Machadodorp
Waterval Boven
Belfast
Dullstroom
Hendrina
Middelburg
(Vaalbank)
Middelburg
(Kruger Dam)
Presidentsrus
Witbank
1.02
3.60
2.22
5.55
1.57
0.66
0.32
138.3
66.6
29.4
0.59
144.8
66.8
27.8
148.3
67.2
36.8
POU
6.6
13.1
35.9
10.8
16.8
71.0
25.1
Final
11.1
14.3
34.8
4.6
16.5
73.0
Raw
10.4.9
12.5
36.1
4.4
16.2
68.9
POU
16.3
11.5
4.23
3.70
0.62
0.71
Final
18.8
4.80
0.85
1.94
0.58
0.48
Raw
28.9
17.2
24.4
4.30
4.91
4.96
121
8.23
7.82
7.03
Raw
8.10
8.01
9.04
9.05
7.28
7.75
pH
8.15
7.51
7.06
Final
7.41
7.84
7.66
7.86
7.93
7.90
8.15
7.72
7.54
POU
8.12
7.77
7.76
7.01
7.97
7.70
24.5
23
21.8
Raw
18.1
21.2
20
23.6
18
21
24.6
26
21.5
Final
23.7
25.6
18
22
18
22
24.4
24.3
20
POU
23.7
26.5
17
21
18
24
Temperature (oC)
Nkangala District Municipality
Conductivity (mS/m)
Turbidity (NTU)
0.25
3
1.55
Chlorine
dosage
(mg/l)
1.3
0.4
1.56
0
0.54
1.03
0.8
120
6.2
3.6
3.4
5.76
10
17.7
46.2
Current
flow rate
0.2
0.22
0.29
Final
1.11
0.15
1.5
0.08
0.51
0.02
0.12
0.08
0.11
POU
0.1
0.37
0.07
0.04
0.52
0.11
Residual
Chlorine
Semerela
Thapane
Nkambako
George’s
valley
Tzaneen
Nkowankowa
Vondo
Phiphidi
Dzingahe
Damani
Mudaswali
Dzindi
Mutshedzi
Tshedza
Tshifhire
Tshakhumare
Tshakhuma
Makhado
Musina
Shikundu
Mhinga
Malamulele
Mutale
Plant
Final
0.95
0.93
2.05
1.34
17.3
0.5
1.61
3.2
3.25
1.04
1.47
1
1.03
0.25
1.55
19.3
0.68
POU
0.71
0.40
1.4
0.81
10.2
0.69
1.78
6.6
2.2
0.67
1
1.2
1.03
0.35
2.53
1.02
0.46
Final
10.3
0.76
1.19
0.41
0.49
1.08
Raw
33.6
5.17
18.8
2.19
4.70
7.19
0.48
1.58
POU
7.52
0.98
0.94
0.48
Turbidity (NTU)
Raw
2.18
2.25
5.29
8.93
25.2
4.88
3.2
21.8
6.62
2.41
3.51
18.8
3.2
15.2
8.93
19.3
3.32
Turbidity (NTU)
POU
45
82.2
92.4
42.8
135.2
4.76
6.32
7.01
7.03
3.51
6.25
28.4
79.2
14.9
16.8
15.6
81.0
73.0
94.0
Raw
9.37
14.6
24.2
49.4
Final
10.3
14.6
22.1
73.2
110.1
115
Raw
7.55
7.02
7.83
6.46
7.36
6.9
7.5
7.16
7.15
7.32
7.05
7.25
7.5
7.23
7.71
7.37
7.82
Final
7.67
7.17
7.58
6.57
7.25
7.0
6.8
6.89
7.07
7.56
7.1
7.72
7.5
7.23
8.01
7.47
7.90
pH
POU
7.61
7.14
7.72
6.83
7.24
7.2
7.0
6.93
7.07
7.66
7.18
7.68
7.13
7.35
8.14
7.15
8.00
Raw
27.4
25.7
27.9
31.0
29.6
24
21.2
20
19
18.2
19.2
19
28.9
21
22
20
31.4
Final
27.7
27.5
32
24.6
29.0
23.4
20
21
18.1
18
18
20
29
20
27
20
28.4
110.8
113.6
POU
11.0
13.9
22.1
110.8
122
6.93
7.96
Raw
7.29
7.29
8.18
7.64
8.93
9.45
Final
6.8
6.8
8.05
9.27
pH
9.21
9.23
POU
6.66
6.66
8.02
9.21
30.1
29.3
Raw
23
25
26.5
30.1
30.5
29.6
Final
22
25
26
30.5
24.7
29.0
POU
23.4
25.8
26.3
24.7
Temperature (oC)
POU
28
29.6
31.7
29.6
26.7
26.2
22
20.5
19.6
18.7
19.1
22
29
21.6
26.2
21
30.4
Temperature (oC)
Mopani district municipality
Final
37.1
39.5
121.8
45.5
136.5
7.38
6.65
6.7
7.28
6.44
6.21
28
66.7
14.9
17.8
14.7
91.2
Conductivity (PS/m)
Raw
34.1
86.9
120.5
40.5
152
5.48
6.63
5.9
6.51
5.92
5.84
25.9
66.3
14.7
14.2
14.8
76.2
Conductivity (PS)
Vhembe District Municipal
Limpopo Province
0.1
0.133
0.4
1.38
1.39
0.7
Chlorine
dosage
(mg/l)
0.35
0.24
0.37
0.52
0.75
0.9
0.34
1.54
0.27
0.28
1.2
0.8
0.4
1.2
0.06
0.6
0.35
Chlorine
dosage
(mg/l)
6
25
1
1
6.9
7.9
Current
flow
(Ml/D)
24
1.9
0.3
2.3
0.8
4
16
0.78
2.07
30
18
12
20
10
37
18
3.5
Current
flow
(Ml/D)
0.1
0.13
0.27
0.12
Residual
Chlorine
(mg/l)
Final POU
0.4
0.12
1.3
0.8
0.56
0.50
0.3
0.24
Residual
Chlorine
(mg/l)
Final POU
0.19
0.27
0.19
0.02
0.06
0.05
0.52
0.22
0.51
0.08
0.82
0.7
0.3
0.17
1.5
0.13
1.5
0.5
0.6
0.57
1.0
0.2
0.6
0.34
0.23
0.1
0.4
0.21
0.04
0.04
1.2
0.06
0.13
0.08
Maratapilu
Pietersburg
Seshego
Burgersfort
Ohrigstad
Tubatse
(Prakteseer)
Steelpoort
Bela Bela
Thabazimbi
Nylstroom
(Modimole)
Naboomspruit
Potgietersrus
(Mokopane)
Letsetele
0.39
0.37
2.46
0.4
4.70
6.2
1.2
0.35
POU
1.74
0.63
1.05
Final
1.81
0.26
1.19
POU
6.92
0.26
1.08
Raw
24.4
1.68
96.6
Final
0.60
0.65
1.95
POU
0.50
0.74
0.50
Turbidity (NTU)
Raw
61.9
0.3
23.1
Turbidity (NTU)
Final
2.01
0.38
1.90
Raw
5.97
0.81
17.5
Turbidity (NTU)
5.73
982
41.0
45.4
POU
254
80.4
271
Raw
33.8
45.2
29.2
7.73
28.5
28.6
7.61
8.2
Raw
7.81
7.49
6.81
6.5
8.4
Final
9.26
7.99
7.01
pH
6.8
8.26
POU
8.84
7.73
7.5
POU
36.8
45.6
26.5
Raw
7.56
7.82
8.50
Final
8.48
7.73
8.11
pH
POU
8.02
8.07
8.2
Final
36.4
57.7
41.2
POU
35.4
58.2
47.0
123
Raw
7.92
8.85
8.37
Final
8.62
8.93
7.86
pH
POU
8.16
8.71
8.02
26
25.5
25.6
Raw
22.3
27
25.4
25
24.6
Final
23.5
29
25.6
Raw
23.1
20.1
21.8
Final
22.5
20.2
22.5
Raw
24.2
23.6
25.1
Final
24.5
23.7
23.8
POU
24.6
22.4
22.8
Temperature (oC)
POU
23
20.5
23
Temperature (oC)
26.2
25.5
POU
27
27.5
25.2
Temperature (oC)
Capricorn district Municipality
Final
47.9
45.7
26.1
Conductivity (PS/m)
Raw
20.7
45.9
25.4
9.64
Sekhukuni district Municipality
42.5
42.0
Final
97.2
78.8
81.5
Conductivity (PS/m)
94.2
37.2
Raw
63.8
94.6
53.9
7.83
Waterberg district municipality
153.5
Conductivity (PS/m)
116.5
0.16
0.21
0.34
Chlorine
dosage
(mg/l)
0.29
0.23
0.35
Chlorine
dosage
(mg/l)
0.92
0.28
0.1l
0.42
0.32
Chlorine
dosage
(mg/l)
0.87
0.6
17.2
3.6
Current
flow
(Ml/D)
3.9
0.5
13.7
Current
flow
(Ml/D)
2.6
-
5.86
5.8
5.76
Current
flow
(Ml/D)
1
0.37
1.01
0.11
Residual
Chlorine
(mg/l)
Final POU
0.12
0.08
0.15
0.08
0.28
0.16
Residual
Chlorine
(mg/l)
Final POU
0.27
0.22
0.18
0.22
0.25
0.21
2.3
0.21
Residual
Chlorine
(mg/l)
Final POU
0.11
0.2
0.39
0.24
0.27
0.16
0.8
1.68
2.03
1.81
2.11
18
Pela
24.4
Final
14.5
0.64
5.28
13.8
POU
11.8
6.59
1.34
Raw
16.8
16.0
33.3
Final
0.81
1.03
1.54
POU
0.78
2.63
4.32
Turbidity (NTU)
Raw
50.3
167
33.7
Madibeng
Hartbeespoort
Temba
0.86
0.35
POU
3.78
0.37
1.51
4.76
Turbidity (NTU)
Final
4.27
2.01
0.52
4.11
Raw
50.2
15.9
9.17
4.11
Turbidity (NTU)
Madikwe
Koster
Swartruggens
Bloemhof
Christiana
Potchefstroom
SchweizerReneke
Ventersdorp
Itsoseng
Plant
28.5
31.3
POU
72.0
89.9
16.1
53.7
Raw
31.5
24.4
40.7
7.32
7.58
Final
7.39
7.32
7.66
8.36
7.77
7.35
POU
7.42
7.43
7.58
8.29
25.0
19.7
Raw
23.0
28.4
24.4
28.5
19.4
20.3
Final
25.7
27.1
25.0
27.7
8.54
POU
12.3
4.3
52.9
7.46
Raw
7.8
8.1
8.05
6.39
Final
8.07
7.65
7.05
pH
7.1
POU
8.1
7.63
7.42
23.4
Raw
26.0
24.0
29.2
Final
35.7
18.3
40.7
POU
37.3
23.6
39.4
124
Raw
7.9
8.5
8.17
Final
7.61
8.98
7.61
pH
POU
7.64
8.62
7.57
24.2
POU
26.2
25.0
20.0
Raw
26.0
25.9
26.8
Final
26.0
26.3
25.8
POU
26.1
27.3
24.8
Temperature (oC)
24.5
Final
25.9
24.4
26.0
Temperature (oC)
25.0
22.2
POU
25.5
30.4
24.7
27.1
Temperature (oC)
Eastern District Municipal
8.54
Final
12.3
8.1
33.9
Conductivity (PS)
8.38
Raw
11.8
16.5
42.9
7.6
7.26
Raw
8.25
8.36
8.04
8.15
pH
Rustenburg District Municipality
25.3
30.5
Final
76.5
59.6
16.6
50.6
Conductivity (mS/m)
24.1
29.4
Raw
46.7
50.3
17.1
23.0
Conductivity (PS/m)
Southern District Municipality
North West Province
3
4.8
3
Chlorine
dosage
(mg/l)
Chlorine
dosage
(mg/l)
3.5
3.5
Not
Working
8.3
1.37
9.6
6.2
Not
Working
2.1
3.85
Chlorine
dosage
(mg/l)
48
10.35
40
Current
flow
(Ml/D)
1.1
24.0
2.0
3.4
Current
flow rate
9
0.9
5.7
3.5
20
4.01
Current
flow
(Ml/D)
0.19
0.02
0.89
POU
0.62
0.23
0.00
Residual
Chlorine
(mg/l)
Final POU
1.45
0.03
0.52
0.07
1.92
0.59
3.52
Final
2.6
1.74
0.00
Residual
Chlorine
1.98
0.11
Residual
Chlorine
(mg/l)
Final POU
0.12
0.00
3.19
0.23
0.52
0.07
0.19
0.08
Pudumong
1.4
11
Mafikeng
Mmabatho
1.18
2.14
Final
12.9
1.98
1.78
POU
11
Raw
9.13
Final
1.05
POU
2.31
Turbidity (NTU)
Raw
14.2
Groot-Marico
Turbidity (NTU)
29.2
44.1
POU
13.2
Raw
63.9
7.5
8.94
Raw
7.88
8.74
7.98
Final
7.85
8.03
7.6
POU
7.85
27.3
25.6
Raw
25.3
24.4
26.1
Final
25.5
Final
61.9
POU
62
125
Raw
8.24
Final
7.86
pH
POU
7.75
Raw
26.3
Final
27.6
POU
27.0
Temperature (oC)
25.0
23.0
POU
24.5
Temperature (oC)
Buphirima District municipality
27.5
43.2
Final
12.5
Conductivity (PS/m)
32.7
46
Raw
12.7
pH
Central District Municipality
Conductivity (PS/m)
2
Chlorine
dosage
(mg/l)
Not
Working
3.5
2.8
Chlorine
dosage
(mg/l)
10
Current
flow
(Ml/D)
42
20
0.9
Current
flow
(Ml/D)
0.69
0.12
Residual
Chlorine
(mg/l)
Final POU
0.91
0.08
2.88
1.66
Residual
Chlorine
(mg/l)
Final POU
0.00
0.00
Assegaai
Belgrade
Bethesda
Ceza
Enyokeni
Frischgewaagd
Greytown
Hlanganani
Hlokozi
Itshelejuba
Ixopo
Jozini
Kwazibusele
Manguzi
Mbazwana
Middeldrift
Mpungamhlophe
Mseleni
Mtwalume
Nongoma
Pongola
Richmond
Thulasizwe
Tongaat Hullet
Ulundi
Umbumbulu
Vulamehlo
Weenen
Wild Coast
Plant
23.1
25.8
23.3
315
0.11
17.5
23.4
4.84
28
0.20
5.00
4.36
0.17
9.15
0.89
1.52
1487
2.4
N.D
1610
70.6
8.5
4.5
49.7
829
No info
28
ND
2.75
1.22
0.87
27.3
11.3
0.28
10.4
0.21
2.46
7.19
2.37
0.94
0.82
0.1
7.95
0.88
0.99
1.15
1.08
0.22
7.20
3.22
2.47
2.41
0.34
0.77
0.23
1.40
1.13
0.48
Final
1.62
0.2
1.41
6.51
0.42
11.1
0.14
2.52
6.06
0.77
1.21
0.71
0.13
7.67
1.15
1.19
1.36
1.48
0.25
7.38
3.21
1.34
2.60
0.5
0.61
0.34
1.09
ND
0.49
POU
Turbidity (NTU
Raw
11.8
26.9
154
5.79
63.6
5.58
6.79
7.46
7.41
13.1
ND
31.4
18.5
24.81
60.6
21.4
19.9
59.4
ND
27.5
8.44
5.74
4.19
14.6
21.7
No info
10.1
ND
20.9
Raw
12.5
27.8
119
7.19
62.4
5.71
7.45
9.42
7.51
13.7
23.4
31.5
19
27.5
62.3
22.1
20.2
60.6
22.8
28.6
8.87
9.44
5.24
18.1
20.8
15.2
11.5
ND
23.2
Final
126
12.1
28.7
64.3
7.06
61.8
5.89
7.78
10.2
7.56
13.8
22.6
31.8
18.9
27.7
62.5
22.3
21
61.4
23.1
28.4
9.01
9.56
5.18
19.6
20.3
15.8
11.6
ND
23.7
POU
Conductivity (mS/m)
6.88
7.5
7.77
7.35
8.03
7.28
7.05
7.69
10.1
6.99
7.00
8.15
6.34
6.59
7.66
7.6
7.94
7.78
ND
7.55
7.59
7.32
6.55
7.62
7.64
No info
7.41
ND
7.5
Raw
6.83
7.68
7.8
7.34
8.09
7.35
7.02
7.67
7.48
6.96
7.12
7.92
6.4
6.60
7.99
7.87
7.99
8.06
ND
7.28
7.36
7.01
6.92
7.73
7.52
7.43
7.85
ND
7.49
Final
pH
KwaZulu-Natal Province
6.86
7.68
8.36
7.42
8.15
7.36
6.6
7.8
7.48
6.96
7.23
7.94
7.5
7.67
8.26
7.97
7.81
8.14
7.5
7.38
7.26
7.54
7.04
7.72
7.65
No info
7.81
ND
7.65
POU
0.68
0.00
0.00
1.7
0.00
0.51
<0.10
0.01
<0.01
1.09
<0.10
0.84
<0.40
0.51
0.72
<0.10
0.00C
0.63
<0.10
2.20+
1.67
0.70
1.23
<0.10
1.24
0.50
<0.10
0
ND
Final
0.00
0.00
1.85
0.39
0.00
0.14
<0.10
0.04
<0.1
1.71
<0.10
0.00
<0.20
0.17
0.97
<0.10
0.00 C
0.09
<0.10
2.20+
0.60
0.20
0.20
<0.10
0.65
0.10
<0.10
ND
ND
POU
Residual (mg/l)
Plettenberg
bay
Knysna
Rheenendal
Ruigter
George
Wilderness
Sandhoogte
Friemersheim
Kleinbrak
River
Great River
Riversdale
Still Bay
Albertinia
Plant
2.02
1.09
0.95
6.66
3.93
0.80
29.2
11.9
1.03
78.0
0.73
0.39
1.06
0.12
0.6
1.02
2.32
0.95
1.09
0.97
7.1
1.03
0.87
0.66
1.39
0.52
3.23
1.71
11.7
18.2
1.62
1.47
1.27
12.1
POU
0.80
Final
0.71
Raw
2.11
Turbidity (NTU)
6.75
6.48
6.35
6.5
7.13
6.97
6.49
7.01
7.18
4.53
4.61
5.26
Raw
4.9
7.5
7.40
11.10
8.69
7.68
6.83
7.12
6.52
10.23
8.95
8.11
Final
10.24
pH
7.06
8.81
9.99
9.5
8.99
7.13
8.88
7.9
9.63
9.48
8.57
POU
9.78
17
14.4
14.8
19.8
23
23
12.3
14
12.6
13.8
12.7
14.2
Raw
25
127
20.4
13
14.7
16.4
23
14.6
14.5
13.4
14.7
13.8
13.8
Final
14.8
17.3
15.4
16.9
14.7
14.6
16.1
16.2
16.7
15.2
14.5
15.1
POU
15.5
Temperature
(oC) m)
5
3.2
4
1.5
11
0.67
4
60
2
5
1
30
27
Design Capacity
(Ml/day)
Ehlanzeni district Municipality
Western Cape Province
2.5
3.2
1
7
0.4
1.9
6.6
1.5
3.6
2.88
23
25
Current
flow
(mg/l)
1.4
4.86
1.26
1.32
2.9
2.14
2.5
1.54
1.28
1.32
2.1
2.3
Chlorine
dose
(mg/l)
0.21
0.67
0.09
1.07
0.31
1.26
0.56
0.27
1.04
0.06
0.32
0.13
0.15
0.00
0.12
0.20
0.14
0.89
0.22
0.42
0.18
0.11
Residual
Chlorine
(mg/l)
Final POU
0.1
0.14
Malelane
Matsulu
KaNyamazane
regional
KaNyamazane old
plant
Sabie
White River regional
White River Country
estate
Nelspruit
Hazyview
Lydenburg
Plant
0
0
0
132
38
24
128
0
0
0
15
83
220
0
7
0
18
80
95
0
0
0
0
0
0
0
0
0
0
0
0
0
7
0
180
72
120
204
0
64
0
7.7 × 104
180
Total Coliforms (cfu/100 ml)
Raw
Final
POU
220
0
22
90
0
0
64
0
0
Heterotrophic Plate Counts (cfu/ml)
Raw
Final
POU
432 × 104
3.8 × 102
22
1.0 × 103
0
0
2.0 × 103
0
0
Ehlanzeni District Municipality
Mpumalanga Province
132
38
24
18
80
95
64
0
0
0
0
0
0
0
0
0
0
0
2
0
0
Faecal coliform (cfu/100 ml)
Raw
Final
POU
220
0
12
90
0
0
64
0
0
Microbiological water quality data for the district municipalities of Mpumalanga and
Limpopo Provinces of South Africa
Appendix 3.4
Machadodorp
Waterval Boven
Belfast
Dullstroom
Hendrina
Middelburg
(Vaalbank)
Middelburg (Kruger
Dam)
Presidentsrus
Witbank
72
92
40
100
129
84
7.2 ×104
0
0
0
1
0
2.2 × 106
7.5 × 107
0
400
2.9 × 104
1.8 × 106
6.5 × 103
Total Coliforms (cfu/100 ml)
Raw
Final
POU
51
0
14
480
8
0
780
0
0
89
7
0
200
0
0
70
3
2
Nkangala District Municipality
Heterotrophic Plate Counts (cfu/ml)
Raw
Final
POU
1.94 × 104
0
170
3.6 × 105
79
4
3.84 × 106
2
0
7.2 × 104
85
20
2.56 × 105
1
0
1.2 × 103
180
82
10
360
132
0
2
3
0
8
5
Faecal coliform (cfu/100 ml)
Raw
Final
POU
44
0
5
156
2
0
72
0
0
5
2
0
13
0
0
27
2
0
Semarela
Thapane
Mudaswali
Nkambako
George’s Valley
Tzaneen
Nkowankowa
Letsetele
4.3 × 103
800
3.6 × 103
0
250
0
130
Total Coliforms (cfu/100 ml)
Raw
Final
POU
1.8 × 104
0
0
3.4 × 103
0
0
1.4 × 103
0
0
370
70
10
460
92
5
700
80
0
1.7 × 103
10
0
1.8 × 104
48
0
Mopani District Municipality
3 × 103
140
Heterotrophic Plate Counts (cfu/ml)
Raw
Final
POU
5.2 × 105
0
0
6 × 102
0
0
3.8 × 104
120
0
7.2 × 103
260
30
4.6 × 105
7.8 × 103
79
4.2 × 105
3.1 × 104
3
3.6 × 104
170
20
3.6 × 106
8.0 × 103
10
6.5 × 103
2.0 × 103
6.2 × 105
1.6 × 104
Total Coliforms (cfu/100 ml)
Raw
Final
POU
570
28
10
250
21
5
2.5 × 103
172
0
200
0
0
2.1 × 103
0
0
5 × 102
0
0
1.3 × 104
0
0
0
0
0
0
0
0
0
0
0
0
0
0
5 × 102
0
0
1.4 × 103
0
0
Vhembe District Municipal
Heterotrophic Plate Counts (cfu/ml)
Raw
Final
POU
5.7 × 104
2.5 × 103
280
4 × 103
2.7 × 103
1.7 × 103
5
1 × 10
180
14
1.1 × 104
0
0
7 × 103
0
0
0
0
0
5.6 × 106
0
0
0
0
0
0
0
0
0
0
0
2 × 102
0
0
3.2 × 105
0
0
4 × 102
0
0
Mhinga
Malamulele
Mutale
Vondo
Phiphidi
Dzingahe
Damani
Dzindi
Mutshedzi
Tshedza
Tshifhire
Tshakhumare
Tshakhuma
Makhado
Shikundu
Plant
Limpopo Province
0
0
0
0
Faecal coliform (cfu/100 ml)
Raw
Final
POU
0
0
0
0
0
0
680
0
0
220
1
0
150
0
0
60
0
0
330
0
0
1.1 × 103
23
0
2.1 × 103
610
Faecal coliform (cfu/100 ml)
Raw
Final
POU
500
12
5
150
0
1
138
15
0
100
0
0
102
0
0
0
0
0
4.5 × 103
0
0
0
0
0
0
0
0
0
0
0
0
0
0
3.8 × 105
0
0
7.8 × 103
0
0
Maratapilu
Pietersburg
Seshego
Burgersfort
Ohrigstad
Tubatse (Prakteseer)
Steelpoort
Bela Bela
Thabazimbi
Nylstroom
(Modimole)
Naboomspruit
Potgietersrus
(Mokopane)
0
0
Total Coliforms (cfu/100 ml)
Raw
Final
POU
7.5 × 104
30
75
160
20
0
1.2 × 104
0
0
0
Heterotrophic Plate Counts (cfu/ml)
Raw
Final
POU
1.6 × 104
39
1.8 × 105
0
0
3.4 × 104
279
130
131
Total Coliforms (cfu/100 ml)
Raw
Final
POU
270
2
2.4 × 103
0
0
1.9 × 103
0
40
Capricorn District Municipality
Heterotrophic Plate Counts (cfu/ml)
Raw
Final
POU
5.4 × 105
180
112
204
34
24
2.1 × 104
26
0
0
Sekhukuni District Municipality
0
3
2.5 × 103
1.9 × 103
0
0
9.0 × 105
4.5 × 103
240
72
Total Coliforms (cfu/100 ml)
Raw
Final
POU
600
20
0
2.2 × 104
6
0
820
16
2
Waterberg District Municipality
Heterotrophic Plate Counts (cfu/ml)
Raw
Final
POU
2.8 × 104
240
20
1.5 × 105
7
2
5.7 × 104
96
16
0
0
0
0
Faecal coliform (cfu/100 ml)
Raw
Final
POU
100
0
80
0
0
210
0
7
Faecal coliform (cfu/100 ml)
Raw
Final
POU
448
3
4
7
1
2
200
1
0
0
250
60
Faecal coliform (cfu/100 ml)
Raw
Final
POU
100
2
0
660
3
0
610
60
0
Wilge
Botanical
Warden
Vrede
Memel
Villiers
Tweeling
Frankfort
Oranjeville
Koppies
Parys
Vredefort
Edenfort
Plant
-
0
0
0
0
0
0
0
0
0
0
0
0
0
132
0
0
0
5
12
0
0
0
0
0
0
0
0
0
Total coliforms (cfu/100 ml)
Raw
Final
POU
Free State Province
Raw
-
0
0
0
0
0
0
0
0
0
0
0
0
-
0
0
0
3
5
0
0
0
0
0
0
0
0
0
Faecal Coliforms (cfu/100 ml)
Final
POU
Putumong
Groot Marico
Mafikeng
Mmabatho
Madibeng
Hartbeespoort
Temba
Madikwe
Koster
Swartruggens
Pela
Bloemhof
Christiana
Potchefstroom
Schweizer-Reneke
Ventersdorp
Itsoseng
Plant
83
0
2
9
0
4
123
0
5
70
0
32
16
0
3
16
37
0
4
31
3
8
4
3
288
2
17
0
1
31
0
5
3.8×102
133
0
15
Buphirima District Municipality
Total coliforms (cfu/100 ml)
Raw
Final
POU
278
14
402
Central District Municipality
Total coliforms (cfu/100 ml)
Raw
Final
POU
5.9×102
6.0×102
3.3×102
Eastern District Municipality
Total coliforms (cfu/100 ml)
Raw
Final
POU
8.1×102
8.8×102
133
262
Rustenburg District
Total coliforms (cfu/100 ml)
Raw
Final
POU
5.6×102
5.0× 02
3.0×102
4.9×102
9.0×102
2.9×102
Total coliforms (cfu/100 ml)
Raw
Final
POU
Southern District Municipality
North West Province
Raw
Raw
0
0
0
5
0
0
13
0
0
0
0
2
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
23
0
1
Faecal Coliforms (cfu/100 ml)
Final
POU
35
3
30
Faecal Coliforms (cfu/100 ml)
Final
POU
0
0
0
Faecal Coliforms (cfu/100 ml)
Final
POU
65
30
24
38
Faecal Coliforms (cfu/100 ml)
Final
POU
60
30
64
36
0
0
0
4×102
24
Raw
Raw
Raw
Faecal Coliforms (cfu/100 ml)
Final
POU
Assegaai
Belgrade
Bethesda
Ceza
Enyokeni
Frischgewaagd
Greytown
Hlanganani
Hlokozi
Itshelejuba
Ixopo
Jozini
Kwazibusele
Manguzi
Mbazwana
Middeldrift
Mpungamhlophe
Mseleni
Mtwalume
Nongoma
Pongola
Richmond
Thulasizwe
Tongaat Hullet
Tugela Estate
Ulundi
Umbumbulu
Vulamehlo
Wild Coast Sun
Plant
Raw
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
134
0
0
0
44
82
44
0
32
866
0
ND
0
No info
0
0
16
435
0
1
0
2
ND
0
No info
ND
0
0
11
1
1
0
6
0
125
0
ND
ND
ND
0
ND
0
ND
0
0
2419
2419
0
ND
0
0
ND
0
No info
ND
0
ND
ND
ND
Total coliforms
Final
POU
Raw
KwaZulu-Natal Province
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
0
0
0
0
30
0
0
5
53
0
ND
0
No info
0
0
0
9
0
ND
0
0
ND
0
No info
ND
0
0
1
0
Faecal Coliforms
Final
POU
0
0
0
0
36
0
ND
ND
ND
0
ND
0
ND
0
0
4
3
0
ND
0
0
ND
0
No info
ND
0
ND
ND
ND
Idutywa
Elliotdale
Butterworth
Cintsa
Kei Mouth
Morgans Bay
Hagahaga
Cathcart
Adelaide
Bedford
Graaff-Reinet
Aberdeen
Willowmore
Pearston
Somerset East
Cookhouse
Joubertina
Louterwater
Kareedouw
Hankey
Patensie
Humansdorp
Jeffreys Bay
Port Alfred
Sea Field
Boesmanrivier
Plant
12
ND
1
ND
64
11
9
132
14
17
5
3
1
6
81
6
15
5
3
16
82
19
17
227
22
23
13
4
4
18
122
11
476
216
273
207
ND
175
ND
41
346
167
135
89
11
ND
9
27
32
68
19
22
153
22
29
183
23
19
15
13
146
52
Amathole District Municipality
Total coliforms (cfu/100 ml)
Raw
Final
POU
69
ND
8
ND
ND
73
63
427
30
304
22
34
46
63
123
16
Total coliforms (cfu/100 ml)
Raw
Final
POU
Cacadu District Municipality
Eastern Cape Province
Raw
5
ND
0
ND
15
0
6
12
1
6
3
0
0
1
11
0
7
1
1
4
21
0
12
91
3
7
5
2
0
2
19
0
98
19
25
0
ND
4
ND
17
25
25
2
0
6
0
9
4
ND
3
4
9
6
0
9
98
0
6
0
7
10
11
Faecal Coliforms (cfu/100 ml)
Final
POU
13
ND
1
ND
ND
5
43
101
6
27
19
5
0
17
25
0
Faecal Coliforms (cfu/100 ml)
Raw
Final
POU
Umtata
Mqanduli
Tsolo
Mngqeleni
Lutsheko
Libode
Umzimvubu
Bulolo
Mt Ayliff
Mt Frere
Maclear
Sonwabile
Ugie
Lady Grey
Aliwal North
Burgersdorp
Barkley East
Elliot
Cradock
Molteno
Queenstown
Sada
Cofimvaba
Dordrecht
Machubeni
Ungcobo
All Saints Hospital
2
84
7
68
14
100
0
11
13
3
ND
18
73
26
140
8
55
40
Raw
2
0
40
13
13
32
32
27
23
0
62
8
18
7
41
32
519
411
09
220
69
171
212
632
157
156
136
150
56
89
51
17
36
72
240
27
0
223
ND
ND
101
12
71
142
420
103
2
OR Tambo District Municipality
Total coliforms (cfu/100 ml)
Raw
Final
POU
320
75
252
87
234
194
236
169
Raw
Ukwakhahlamba District Municipality
Total coliforms (cfu/100 ml)
Raw
Final
POU
Raw
237
ND
66
268
321
378
298
354
215
Chris Hani District Municipality
Total coliforms (cfu/100 ml)
Raw
Final
POU
0
16
0
6
0
0
0
7
2
0
16
0
6
6
0
0
8
7
4
0
8
0
0
0
3
7
9
0
ND
0
0
0
3
5
80
92
160
20
4
6
31
20
174
32
25
18
17
2
1
0
3
2
4
0
38
27
15
5
2
0
15
4
7
0
Faecal Coliforms (cfu/100 ml)
Final
POU
27
30
15
11
29
0
13
19
Faecal Coliforms (cfu/100 ml)
Final
POU
32
ND
5
22
17
16
13
20
19
Faecal Coliforms (cfu/100 ml)
Final
POU
Plettenberg bay
Knysna
Rheenendal
Ruigte
George
Wilderness
Sandhoogte
Friemersheim
Kleinbrak Rivier
Great River
Riversdale
Still Bay
Albertinia
Plant
6.6×102
9.4×102
1.1×102
1.3×102
5.9×102
7.5×102
5.2×102
2.4×102
1.02×102
2.05×102
3.0×102
ND
2.6×102
137
59
39
34
12
11
1
2
0
8
9
12
ND
8
67
34
20
30
13
8
3
1
13
14
17
ND
26
Total coliforms (cfu/100 ml)
Raw
Final
POU
Western Cape Province
3.3×102
3.3×102
3.3×102
3.3×102
3.3×102
3.3×102
3.3×102
3.3×102
3.3×102
3.3×102
3.3×102
3.3×102
3.3×102
7
0
25
0
0
0
0
0
0
10
0
ND
12
9
50
35
22
47
2
0
0
8
25
0
ND
28
Faecal Coliforms (cfu/100 ml)
Raw
Final
POU