How Effective are Alternative Ways of Laundry Washing?

ENVIRONMENTAL CHEMISTRY
y
Anke Kruschwitz, Aline Augsburg and Rainer Stamminger
How Effective are Alternative Ways
of Laundry Washing?
Laundry washing consumes resources. It is therefore a clear task
for everyone, especially the industry and the consumer, to try to
reduce the amount of resources needed as much as possible.
Many possibilities and alternatives to the classical cleaning process using a washing machine and a readily formulated detergent
are in discussion and are offered to the consumer. Task of this
study is to investigate the effectiveness of some of these alternative methods to see whether the task to save resources can be accomplished by them. This is done by carrying out washing performance tests in a common household washing machine using
stain monitors and stain strips as indicators for the washing effect
in a 30 8C and 60 8C cotton program and comparing those alternatives (soap nuts, soapwort, two kind of wash-balls) with the use
of regular detergent and washing with pure water. As result it is
shown, that none of the investigated alternative cleaning methods does deliver any washing effect better than the result
achieved with pure water, besides for soapwort that also included
other surfactants. Interesting to note that on most stains the use
of just 50 % of the detergent delivers already a cleaning performance not much lower as 100 % of detergent does provide.
Key words: Laundry washing, soap nut, soapwort, wash ball,
cleaning effect
Wie wirksam sind alternative Arten des Wäschewaschens?
Wäsche waschen verbraucht Ressourcen. Aus diesem Grund ist
es eine allseits akzeptierte, wichtige Aufgabe, diesen Ressourcenverbrauch zu reduzieren. Viele Möglichkeiten und Alternativen zum klassischen Reinigungsprozess in der Waschmaschine,
sowie zu herkömmlichen Waschmittelformulierungen stehen
zur Diskussion und werden dem Endverbraucher zur Erreichung
dieses Ziels angeboten. Ziel der vorliegenden Studie ist es, die
Wirksamkeit einiger dieser Alternativen zu dem klassischen
Waschverfahren zu erfassen, um zu klären, ob durch ihre Anwendung eine Ressourceneinsparung erzielt werden kann. Aus
diesem Grund sind Reinigungsleistungstests in gängigen Haushaltswaschmaschinen in einem 30 8C- und 60 8C-Baumwollprogramm unter Verwendung verschiedener, alternativer Waschmittel (Waschnüsse, Seifenkraut, zwei unterschiedliche Waschbälle)
mit und ohne Einsatz einer herkömmlichen Waschmittelformulierung durchgeführt worden. Die Reinigungswirkung wurde dabei sowohl durch Fleckenmonitore als auch angeschmutzte
Teststreifen gemessen. Als ein Ergebnis zeigt sich, dass keine
der untersuchten Waschmittelalternativen ein besseres Reinigungsergebnis liefert als das Waschen mit reinem Wasser! Ausgenommen davon ist das Waschen mit einem Seifenkraut enthaltenden Waschmittel, welches aber im Wesentlichen auch die
Inhaltstoffe eines herkömmlichen Waschmittels enthält. Weiterhin zeigt sich, dass für die Mehrheit der Anschmutzungen bereits
50 % der empfohlenen Menge der herkömmlichen Waschmittelformulierung bereits eine ähnliche Reinigungsleistung erzielen
wie 100 %.
Stichwörter: Wäschewaschen, Waschnüsse, Seifenkraut, Waschbälle, Reinigungseffekt
Tenside Surf. Det. 50 (2013) 4
1 Introduction
Laundry washing uses a considerable amount of resources.
Pakula has estimated the global energy and water consumption for automatic laundry washing to be at about 100 TWh
of electricity and 20 km3 of water per year [1]. But not only
these resources are needed; also the detergent used is a valuable resource which may also have adverse effects on the local and global environment. Globally the laundry detergent
market is estimated to a value of 77 billion US$ a year [2].
Life Cycle Analysis (LCA) show that by far the most important impact from laundry washing is due to the operation of
the washing machine itself and only a small part is coming
from the detergent. However, for some environmental parameters like the chemical oxygen demand the detergent
contributes significantly [3].
Laitala et al. [4] report that detergents are becoming more
environmentally friendly, mainly due to changes made in
the formulations. Detergent compositions with enzymes
function on lower temperatures, thereby reducing energy
consumption in use. The compact form of detergents reduces the transportation, packaging, chemicals, water and
storage needs resulting in environmental benefits. Additional improvements can be reached by continuing the replacement of harmful chemicals with bio-based, readily degradable ingredients [5]. Parts of the consumer themselves
tend to reduce the amount of detergent used in a washing
process by dosing less detergent as recommended by the
manufacturer. Surprisingly, the 30 % of the consumers
found in a German consumer study which committed to
use less detergent did not show a significant higher level of
dissatisfaction with the washing result [6]. Another alternative to lower environmental effects of washing is to wash at
lower temperature. Here significant saving of energy can be
gained either by accepting lower washing performance or
extending the time the washing program takes [7].
Roy et al. [8] report about the soil washing potential of a
natural surfactant as an attractive alternative to synthetic
surfactants in the remediation of contaminated soils. They
report on their tests of saponins isolated from Sapindus mukurossi, a tree generally grown in tropical regions of Asia.
Saponins in general are complex substances and are essentially glycosides with their aglycones related to either sterols
or triterpenes. Extraction of the fruit pericarp with water has
been the most commonly used method, as well as for scientific as domestic uses such as washing hair and fabric. The
aqueous solution thus obtained can be purified by isolating
the saponin fraction. Their \promising results warrant
further research to establish the usefulness of plant-based
surfactants for soil washing applications."
The effect of using ultrasonic fields for washing is also
frequently reported. Moholkar and Warmoeskerken [9] have
studied the position in the ultrasound field and the gas content of the fabric and of the washing medium on the efficiency of ultrasonic textile washing. The results reveal that
these parameters influence washing efficiency by means of
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Anke Kruschwitz et al.: How effective are alternative ways of laundry washing?
ultrasound wave phenomena and acoustic cavitation. This
study explains the actual physical mechanism of the ultrasonic textile washing process. Some optimization strategies
for a large-scale ultrasonic washing process are also outlined.
Schambil et al. [10] report that Sanyo launched in 2001 an
ultrasonic washer in Japan. They report that according to Sanyo, the use of ultrasonic waves in special wash cycles can
make laundry detergents totally redundant (zero-detergent
cycle). Comprehensive studies of primary and secondary detergency carried out by, among others, the Japanese Soap &
Detergent Association, the Japanese Consumer Affairs Centre and all well-known appliance and washing machine
manufacturers, all point to the conclusion that the performance of the washer is not acceptable in the absence of detergent, according to Schambil et al. Schambil et al. themselves made tests of 18 alternative washing technologies
grouped into solvent-based and solvent-free systems. The
first group contained aqueous, non-aqueous and purely
physical methods. In the group of solvent-free systems,
gases and physical methods were evaluated. The results
published show no details of the achieved results but only
some kind of value benefit analysis of those 18 alternative
washing technologies based on arguments like washing performance, textile care, eco-toxicity, handling, safety and
economy. They conclude that no \alternative wash methods
were identified that could even approach the level of performance of today’s household laundry washing in the foreseeable future\ [10].
Recently, Laitala and Kjeldsberg performed a test of soap
nuts, laundry balls, washing pellets and laundry magnets
[11] and compared the results with washing with conventional compact color detergent, and washing with water
only. The cleaning effect was evaluated according to standard EN 60456:2005 at 40 8C. The results show that the
cleaning effect of the four alternative laundry products was
equal to that of water alone. However, they did use only the
four soils of the IEC standard stain strip which are artificially soiled and aged to remain stable for a longer period
of time.
The question remains open if for some of the alternative
washing technologies benefits can be achieved for at least
some of the common stains to be cleaned. Therefore, it was
the task of this investigation to evaluate in detail the primary
washing efficiency of some commercially available alternative washing technics under realistic household conditions
at different washing temperature with a broad range of common stains.
. Test strips following IEC60456 with stains of sebum, carbon black/mineral oil, blood, cocoa and red wine2. One
part is of pure cotton without stain to allow detecting
some reposition effect. Three strips per test run are
added, each fixed on one towel.
. Stain monitors of various stains with different sensitivity
(Tab. 1) of size 5 cm · 5 cm fixed on a polyester-cotton
fabric3. Three of these monitors were added per test run.
After washing the test monitors were dried and ironed. Later
optical reflection was measured following IEC60456 using a
photometer Datacolor Spectralflash SF600X.
As alternative washing techniques following was used:
. Soap-nuts4 are declared of Asian origin. 6 to 8 halve
shells shall be used according to the instructions given
for washing, placed in the drum within a cotton bag.
No additional detergent is recommended to be used.
. Soapwort5 is presented as a liquid detergent containing
5 – 15 % extract of Soapwort, 5 – 15 % amphoteric surfactants and 5 – 15 % anionic surfactants. Additionally, less
as 5 % of lactic acid for water softening in contained.
For all washing temperatures and water hardness 30 ml
of this detergent is recommended for use.
. Wash-balls6 are balls of 3.7 cm diameter and 25 g weight
and consist of blue rubber. For a load of 3 kg laundry six
balls are added. As it is recommended that those washballs can substitute detergent or make it obsolete, the
balls are tested without and with 50 % of detergent.
. Eco-wash-ball (\ ko-Waschball"7) is a ball of 10.5 cm diameter made of SEBS (Styrol-Ethylen-Butylen-Styrol).
Inside it has 110 g of ceramic balls and allows the water
to penetrate through holes in its outer surface. It is supposed to be used as alternative to commercial detergent
and therefore tested without additional detergent. The
ball is added to the wash load.
Ident-Code3
2 Experimental Procedure
Test were done in a commercially available washing machine1 following IEC60456 methodology [12] using a normal
cotton program at 30 8C and 60 8C and a load of 3 kg cotton
articles (two sheets, four pillow cases and five towels – all
according to IEC60456). The load size was selected to reflect
average consumer like conditions [13]. Water hardness was
selected to be at (2.5 € 0.2) mmol CaO/l. Detergent A* of
IEC60456 was used at a quantity of 76 g for washing with
100 % dosage or 38 g for 50 % dosage or none if the alternative washing method did claim to deliver good washing results without any detergent.
As indication of the washing efficiency two kinds of test
monitors were used:
3
4
5
6
7
1
Miele Softtronic W4466, maximum capacity of 6 kg cotton
264
Stain sensitivity to
wfk10J
tea
bleach
wfk10 K
coffee
bleach
wfk10WB
blueberry juice
bleach
wfk10Z
chocolate
enzyme
EMPA164
grass
bleach, enzyme
wfk10M
motor oil/pigment
general performance
wfk10Li
red wine, temperature
treated
bleach
wfk10T
ketchup
bleach
wfk90PB
blood
enzyme
wfk20D
pigment/sebum
general performance
Table 1
2
Stain type
Stain monitors used and their sensitivity
Supplier: EMPA Testmaterials AG, Mövenstrasse 12, CH-9015 St. Gallen, Switzerland
Supplier: wfk – Testgewebe GmbH, Christenfeld 10, D-41379 Brüggen-Bracht,
Germany
Supplier: Dalimar, Martin Thul, Trierer Straße 30, 54516 Wittlich, Germany
Supplier: W. Ulrich GmbH, Gewerbering 10, 86922 Eresing, Germany
Supplier: Technotrade GmbH & Co., Im Wolfsgraben 3a, 36414 Unterbeizbach,
Germany
Supplier: JOKA international GmbH, Rheinstraße 90, 77743 Neuried-Ichenheim, Germany
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Additionally, a test setup without any detergent and any alternative washing technique in both programs at 30 8C and
60 8C were executed, as well as with 50 % and 100 % amount
of detergent alone. A treatment consisted of three repetitions for each test set-up.
3 Results and Discussion
In a first step the reflectance values of all stain monitors
were measured once and those of the IEC test strips on four
positions. Then the average and standard deviation of all
measured values for a certain soil was calculated (Tab. 2
and Tab. 4). In a next step the measured reflection values
for those treatments with pure water (without detergent
and without any alternative way of washing technique) was
subtracted to achieve a measure of the benefit of this kind of
treatment (Tab. 3 and Tab. 5). The standard deviation of this
difference was calculated following the rules of error propagation. The results show the additional cleaning effect
achieved by the applied detergent and/or alternative washing technique compared to cleaning with pure water in the
same program. As the ability to be cleaned of the individual
stains is different, a comparison may not be done between
different stains, but only between different treatments.
For the 30 8C cotton program the stain monitors (Fig. 1)
show some cleaning effect on all stains for all treatments
where detergent is added (except on tea when only 50 % of
the detergent is used) and no effect (within the standard deviation) when soap nuts and wash-balls are used. The use of
Table 2
Remission values for stain monitors
Table 3
Remission value differences to pure water treatment for stain monitors
Tenside Surf. Det. 50 (2013) 4
the soapwort product shows some cleaning effect, but less
than those achieved with halve the detergent dosage.
These results are similar in the 60 8C cotton program
(Fig. 2) although here the bleachable stains, like tea, blueberry juice, grass, red wine and ketchup show a significant
higher level of cleaning compared to other stains when detergent is used. This may be due to the activation of bleaching components of the detergent at higher temperatures.
Other stains, which are labeled to be not sensitive to bleaching like motor oil, blood and sebum, do not show this increase in cleaning performance when comparing 30 8C and
60 8C treatments. The cleaning efficiency of soapwort does
not show to increase from 30 8C to 60 8C program. Soap nuts
and all kinds of wash-balls do not show a significant difference in cleaning performance compared to the treatment in
pure water. The use of just 50 % of the amount of detergent
delivers for all stains at 60 8C at least half of the additional
cleaning performance (compared to pure water) and in
many cases already much more. The product using soapwort delivers especially for fatty stains like chocolate, motor
oil and sebum some level of cleaning performance, but almost no – compared to pure water – for the other stains.
The IEC stain strip result washed at 30 8C (Fig. 3) show a
high value of reflectance difference to pure water treatment
for the use of 100 % and 50 % of detergent especially for the
blood stain. This reflects the well-known effect that blood
stains are easy to clean under cold or warm water with the
use of enzymes as contained in the used detergent. All other
stains show less cleaning effect and red wine does not show
any effect at all at this temperature. This may be due to the
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Table 4
Remission values for IEC test strip
Table 5
Remission values difference to pure water treatment for IEC test strips
Figure 1 Cleaning performance difference of
various alternative processes to pure water treatment at 30 8C cotton program for various stain
monitors
266
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artificial temperature treatment done for this stain to make
it less easy to remove (s. IEC60456, Annex A.3.1.5). Soap
nuts and wash balls again show no significant cleaning effect compared to a cleaning in pure water and a soapwort
containing product performs not much better. This statement stays also for the treatments in the 60 8C cotton programs. Using detergent at this temperature increases the
cleaning performance for all stains compared to the treatment at 30 8C. More detergent delivers more performance,
especially for the cacao and red wine stain. Even the unsoiled part of the stain strip shows some increased remission of the light when washed with detergent and some decrease when no detergent is in the washing solution. Latter
may be due to some soil re-deposition happening when the
wash solution does not contain components which avoid
this effect. At 608 cotton program (Fig. 4) the effects observed on the test strip are essentially the same on a higher
level of reflectance. The red wine stains show only some reflectance difference to pure water when 100 % of detergent
is used.
Summarising all remission value differences to pure
water treatment for both wash temperatures tests and both
type of stain monitors (Fig. 5 and Fig. 6) allows an overall
comparison of the cleaning efficiency of all alternative washing treatments. All treatments of soap-nuts and both kinds
of wash balls do not show any significant better washing effect as a pure water wash. Wash balls used with 50 % of detergent show the same improvement of the wash result as
test done with this amount of detergent alone. Doubling
the amount of detergent shows some clear increase in soil
removal compared to 50 % detergent usage, especially at
higher temperature of 60 8C. Nevertheless, the cleaning performance delivered with 50 % of detergent may be in many
cases already sufficient for normal household purposes,
even at 30 8C. This may be a better strategy to save the environmental burden coming from laundry washing instead of
investing money in dubious alternative washing procedures.
4 Conclusion
Tests have shown that washing with alternative washing
methods like wash balls or soap nuts do not remove soil better than a wash with pure water. Although tests have been
done only with some examples of the broad offer of such alternative ways of washing, it is believed that no better result
will be achieved by any other of those devices. Soapwort for-
Figure 2 Cleaning performance difference of
various alternative processes to pure water treatment at 60 8C cotton program for various stain
monitors
Figure 3 Cleaning performance difference of
various alternative processes to pure water treatment at 30 8C cotton program for various stains of
the stain strip
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Anke Kruschwitz et al.: How effective are alternative ways of laundry washing?
Figure 4 Cleaning performance difference of
various alternative processes to pure water
treatment at 60 8C cotton program for various
stains of the stain strip
Figure 5 Sum of the cleaning performance
difference of various alternative processes to
pure water treatment at 30 8C and 60 8C cotton program for the sum of the stain monitors
(vertical lines show standard deviation following error propagation calculation)
Figure 6 Sum of the cleaning performance
difference of various alternative processes to
pure water treatment at 30 8C and 60 8C cotton program for the sum of the stain strip
(vertical lines show standard deviation following error propagation calculation)
268
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Anke Kruschwitz et al.: How effective are alternative ways of laundry washing?
mulated in a detergent solution has shown some cleaning
effect, but it is unclear how much is the contribution of the
soapwort itself and how much is coming from the other surfactants. Overall the use of detergent seems to be without
alternative when a cleaning effect of soils shall be achieved.
This does not mean that there are no alternatives:
. When clothes are not dirty, not to wash them may be the
best solution.
. When clothes just smell a little, it may be sufficient to
hang them on a line on fresh air for a while.
. When clothes are only slightly soiled a wash at low temperature (e. g. 30 8C) with a reduced amount of detergent
(e. g. 50 %) may already provide a sufficient cleaning result.
. When clothes are soiled with specific stains, it may be
wise to use a separate stain remover and wash afterwards
with less amount of detergent and at lower temperature.
. Washing machines with real physical alternative washing technologies, like ultra-sonic waves, plastic beets,
electrolytic water and others may come, but will have to
prove their effectiveness with experiments similar like
those presented in this paper.
Acknowledgements
Authors would like to thank EMPA Testmaterialien, Switzerland
and WfK Testmaterialien, Germany for providing the test monitors and Marina Niestrath for her support.
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Soil washing potential of a natural surfactant. Environmental Science & Technology 31(1997) 670 – 675.
9. Moholkar, V. S. and Warmoeskerken, M.: Mechanistic aspects and optimization
of ultrasonic washing. Aatcc Review 2 (2002) 34 – 37.
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Ophüls, A.: Will Detergents Disappear? An Evaluation of Alternative Wash
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11. Laitala, K. and Kjeldsberg, M.: Cleaning effect of alternative laundry products. A
comparison of soap nuts, laundry balls, washing pellets, laundry magnets,
water and regular detergent. Household and Personal Care today 7 – 4 (2012),
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12. IEC60456-2012. Clothes washing machines for household use – Methods for
measuring the performance. Geneva, CH: International Electrotechnical Commission.
13. Berkholz, P., Brückner, A., Kruschwitz, A. and Stamminger, R.: Verbraucherverhalten und verhaltensabhängige Einsparpotentiale beim Betrieb von Waschmaschinen. In: R. Stamminger (Hrsg.) Schriftenreihe Haushaltstechnik Bonn,
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Received: 17. 01. 2013
Revised: 06. 03. 2013
y
Correspondence address
Anke Kruschwitz
Universität Bonn
Institut für Landtechnik
Nussallee 5
53115 Bonn
Tel.: +49-2 28-73-59 55
Fax: +49-2 28-73-25 96
E-Mail: [email protected]
[email protected]
The authors of this paper
Dipl. oecotroph. Anke Kruschwitz studied nutritional science and home economics
from 2002 to 2008 at the University of Bonn. In her diploma thesis she evaluates
the use of different rinse aids for drying performance during automatic dishwashing
process. Having finished the studies with diploma in 2008, she has started working
as a scientific assistant in the Household and Appliance Technology Section of the
University of Bonn. In her PhD thesis, she is investigating the laundry washing process regarding the optimization of resource consumption.
Prof. Dr. Rainer Stamminger, University of Bonn. After 17 years of practical experience in the development of washing machines and dishwasher with AEG Hausgeräte Germany Rainer Stamminger was promoted 2002 as professor for appliance
and process engineering at University of Bonn. Main areas of research at University
are consumer behavior of homework with and without using appliances, new products or features, smart appliances, robots for household application and questions
of sustainability of housekeeping.
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