DECLARATION 2 PUBLICATIONS
1. INTRODUCTION
1.3 Drivers for re-use
Nationally, the re-use of greywater is unlikely to solve problems of water scarcity as the volumes involved are relatively small in the overall picture. In eThekwini however, approximately 60% of the potable water sold is used domestically (S. Moodliar 2009, pers.
comm.7), so widespread re-use could have an influence on the local need for increased spending on water purchases and infrastructure such as impoundments, reservoirs and piping.
For individual households and even small communities, water re-use can mean the difference between food security and malnutrition. EThekwini Municipality has increased the cost of water by approximately 10% for the 2010 – 2011 financial year and this will impact poor households in spite of the current level of 9kL free water per household (EThekwini, 2010).
7 S. Moodliar, eThekwini Water and Sanitation, P.O. Box 1038, Durban 4000
Table 1.1: Reported numbers of indicator bacteria in greywater (Adapted from Ottoson and Stenström, 2003 as used in WHO, 2006a). Different values for greywater were given by the various authors and reflect different conditions and habits
Greywater origin
Numbers of indicator bacteria (log numbers / 100 mL) Total coliforms Thermotolerant
coliforms
Escherichia
coli Enterococcus
Bath, hand basin 4.4 1.0 – 5.4
Laundry 3.4 – 5.5 2.0 – 3.0 1.4 – 3.4
Shower, hand basin 2.7 – 7.4 2.2 – 3.5 1.9- 3.4
Greywater 7.9 5.8 2.4
Shower bath 1.8 – 3.9 0 – 3.7 0 – 4.8
Laundry, wash 1.9 – 5.9 1.0 – 4.2 1.5 – 3.9
Laundry, rinse 2.3 – 5.2 0 – 5.4 0 – 6.1
Greywater 7.2 – 8.8
Hand basin, kitchen
sink 5.0 4.6
Greywater, 79%
shower 7.4 4.3 – 6.9
Kitchen sink 7.6 7.4 7.7
Greywater 5.8 5.4 4.6
Worldwide, there is a movement towards addressing the increased demand for water while at the same time trying to cope with the decreasing availability of clean, inexpensive water sources. In the past, water was often viewed as a renewable but finite resource, but it has been suggested (Turton, 2008) that it is in fact a flux with almost infinite options for use, limited only by innovation. This means that previously, water was regarded as a stock item which was used in various ways and eventually became depleted much as the feedstock in an industrial process. What Turton (2008) suggests is that water can be used and treated for re-use in an almost endless cycle. Across the globe, advances have been made in exploiting hitherto untapped sources, developing new industrial practices which use less water in production, reducing demand through pricing structures and in recycling (Forster, 1997). In the urban environment, particularly in Africa, the demand for water can be high and where poor communities are involved, the financial burden of increased pricing can become intolerable, with such communities sinking into extreme poverty. As such, these communities need to investigate ways of using water as fully as possible and to their greatest benefit, before disposal.
According to Winter et al., (2008a; 2008b) it can be assumed that greywater accounts for virtually all the water brought onto an un-sewered site and that the volumes and quality involved increase with increasing affluence. Erikson et al., (2003) and Friedler and Hadari
(2006) suggest that 50 to 80% of the water going to waste is accounted for by greywater, excluding kitchen waste, while Siegrist et al., (1976) assessed a level of 65% and Brown (2009) suggests a level of 60%. Re-use of such water could therefore have a marked impact on the finances of an impoverished household even though, at the levels officially supplied to such areas, it might not have an impact on water savings in the South African national context.
Many countries, notably China, India and others in the east, have for centuries recycled and re- used domestic effluents successfully (Mara and Cairncross, 1989; Ahmed et al., 2003).
According to Adewumi et al., (2006) the attitude of the public in South Africa towards water re-use still needs to be thoroughly assessed as there is resistance.
In the Chinese case, greywater has been viewed as a resource delivering both vital water and nutrients rather than as an unpleasant waste requiring removal (Mara and Cairncross, 1989).
According to Redwood (2008), greywater re-use in developing countries is most often linked to improving domestic food security. Re-use also lends itself to the informal settings often encountered in the developing world.
It is now generally accepted worldwide that there is climate change which has led to more extreme weather patterns. These in turn have resulted in increasing frequencies of drought and floods and a concomitant decrease in food crop production (Stockle et al., 1992; Rosenzweig et al., 2002; Jones and Thornton, 2003). In addition, in many parts of the developing world, there has been a shift from subsistence farming to growing cash-crops, most recently crops for the production of bio-fuel, and this, along with prolonged droughts and severe floods, may have contributed to increased food scarcity and increasing food prices (Woods Institute, accessed July 2010).
Countries such as Sweden and Denmark have addressed the issues of water re-use nationally and there is a functioning system for delivery of greywater to commercial agriculture (Ottoson and Stenström, 2003). This greywater has been treated before reuse. This is largely not the case in the developing world, where greywater re-use is still generally restricted to use by the generating household or, at most, the immediate small community (Morel and Diener, 2006).
With rising food costs worldwide and the advent of child- or elderly relative headed households as a result of the AIDS pandemic, such home or community use can however have a marked impact on communities, both financially and in terms of nutrition and health. This is especially true in South Africa where 17% of the population aged 15 to 49 lives with AIDS and there are an estimated 1.91 million AIDS orphans (StatsSA, 2009). However, for re-use to be successful in the South African setting, a change in perceptions of sanitation practices and the use of water containing human wastes needs to occur (Friedler and Hadari, 2006; Adewumi et al., 2008).