Resource guidelines for greywater use and management Dr Kirsty Carden, University of Cape Town 18 April 2016 Water Research Commission project K5/2592 Development of resource guidelines for greywater use and management
1 Agenda for workshop 1. Welcome and introductions 2. Background to project – status quo / definitions 3. Identification of thematic areas / issues to be addressed 4. Introduction to greywater resource guidelines 5. Way forward / closure
2 Strategic planning “ South Africa is a ‘ water-stressed ’ country, bordering on water scarce…water may become a binding constraint on development, at least in some parts of the country. There is a need for urgent attention to be given to the management and conservation of water resources, especially in stressed water catchments … Addressing supply and demand in the context of unevenly distributed and variable resources is a matter of central importance in national planning. ” (National Planning Commission, 2011) ‘In many parts of the country, we are fast approaching the point at which all of our easily accessible freshwater resources are fully utilised. All South Africans must recognise this situation so that necessary steps are taken to assess current and future demands for water. This will not be an easy task, but with the necessary resolve to plan and implement the required interventions, a secure water future can be achieved.’ – NWRS2, 2013, page 4
3 National surface water storage levels http://niwis.dwa.gov.za/niwis2/SurfaceWaterStorage
4 Predicted total water withdrawals (Source: Hedden, 2016)
5 Resilience-based water management Evolution from the 1990s to present day realisation WSUD SuDS Green and blue water with social IWRM / and ecological IUWM interactions Integrated blue and green water Integrated blue Resilience based, Blue water water addressing the Adding land need to sustain interactions, An economic Sector approach surface runoff and rainfall, capture dominated by approach to infiltration to food, resource value, economics and freshwater and cross scale energy, and engineering, including interactions and ecosystem emphasis on environmental feedbacks services flows supply Adapted from Rockstrom et al., 2014
6 Diversifying household water sources Precipitation Evapo-transpiration Rainwater Harvesting Groundwater Reduced volumes of runoff Greywater reuse Increased Infiltration Reduced Municipal potable water demand Stormwater Reduced wastewater Harvesting discharge
7 Household greywater - What is it? Greywater is untreated wastewater from baths, showers, kitchen and handwash basin, and laundry (i.e. household wastewater excluding toilet waste) Class 1: Bathroom greywater – showers, basins, baths Class 2: Laundry greywater – laundry basins and washing machines Class 3: Kitchen greywater – kitchen sinks and dishwashing machines Only applies to serviced settlements 7
8 Greywater recycling Source: Ana Delétic
9 Simple home-based greywater systems Photos courtesy: Kevin Winter
10 Combined rain- and greywater harvesting
11 Greywater and food security
12 Greywater and food security (2) Photos courtesy: Khanyisa Projects
13 Greywater tower gardens
14 Draft National Sanitation Policy (2016)
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16 Quality issues
17 Greywater management in informal settlements
18 Greywater management in informal settlements
19 Timeline of greywater research
20 Project aims Address (and mitigate) the risks associated with the management and use of domestic greywater, and support the wider uptake of this practice in South Africa, in order to realise diverse benefits such as: • building resilience into the water supply system; • managing water demand; • reducing volumes of greywater to wastewater systems; • reducing diffuse pollution loads from un-serviced settlements
21 Technical background report • Definition of terms and concepts • Role of greywater management in water supply and food security • Applicable regulations / policy / guidelines on greywater use and management • Existing greywater use and management systems • Recommendations for sustainable greywater use and management
22 Greywater guidelines • Greywater quantity / quality and fitness for use / application • Managing risks and uncertainty in greywater use / reuse • Use of greywater to supplement irrigation activities • Greywater management options, including: treatment, disposal and reuse • Planning for (municipal) programme implementation
23 Method • Compile relevant research findings • Survey greywater system users at household scale • Local and national stakeholder workshops • Review of legislative and health aspects • Focus group discussions • Develop guidelines, including simple ‘operations and maintenance’ information, as well as strategic technical background document
24 Thematic areas to be addressed • Health aspects • Legislative issues • Risk management / quantification • Socio-cultural issues • Appropriate applications / uses • Key design considerations
25 Health aspects • Is greywater a health risk? • What are the pathways to infection? • What preventative barriers are there? • What about treatment options? • Is hygiene education important?
Health aspects of re-use of household wastewater (greywater) Dr Jo M Barnes Division of Community Health Faculty of Health Sciences University of Stellenbosch TYGERBERG
27 Household greywater - What is in it? • Soaps, detergents, fabric softeners • Hair products (shampoo, hair conditioner) • Toothpaste • Medicines • Disinfectants • Pesticides • Dyes • Cosmetics • Lint and other fibres • Food particles as well as fats, oils, blood • Human waste products: saliva, sweat, body oils, hair, blood, and some urine and faecal matter
28 Greywater is NOT a “safe” substance • Contains bacteria, viruses, parasites - pathogens able to cause disease in humans or animals • Species and total counts vary widely according to climatic conditions, season, sanitation technology available, sanitation habits of the people living in the dwelling and the disease incidences in the area • Potential re-use of greywater is as much a public health issue as it is a water conservation priority Implementation involves balancing risks 28
29 International restrictions on re-use (1) • Water used to wash articles contaminated with faeces should not be used • Greywater should not be allowed to leave the boundaries of the property and should under no circumstances be allowed to enter the stormwater system • Provision must be made for the safe disposal of excess greywater into the sewage system during rainfall or when too much greywater is produced for the garden to absorb • Greywater should never be allowed to pond or pool where mosquitoes can breed or where it can develop foul smell • “Fail -safe" disposal system required – PRECAUTIONARY PRINCIPLE to be applied 29
30 International restrictions on re-use (2) • Never apply to edible crops • Withhold from areas where children play, such as lawns – as children are highest risk group for acquiring infection. • Withhold if anybody living on the premises is suffering from diarrhoea, ear or skin infections, etc. • Warm water should be stored in a holding tank to cool down. Use within 24 hours; otherwise the bacterial load will rise too high for safety. • Everybody living on the premises where gardens are irrigated with greywater should wash their hands without fail before eating or drinking. 30
31 Realities in developing countries • Far larger proportion of population poverty-stricken • Burdens of disease predominated by infectious diseases • 40% of women aged 25 - 35 HIV + in South Africa • Very poor sanitation - high infection pressure • Direct link between food and contaminated water • Populations more inclined towards 'civil disobedience' due to lack of enforcement of regulations 31
32 Who is most at risk of water-related disease? • Newborns, babies and children • Pregnant women and their developing foetuses • Old people • Individuals with compromised immunity such as those with TB, HIV/AIDS • Persons who are chronically malnourished • Patients on long-term medication • Persons with pre-existing chronic diseases such as diabetes, kidney failure, liver failure • Persons who abuse alcohol or other drugs = Large proportion of SA population
33 Risks related to irrigating edible crops • Never apply directly to edible crops - especially not to vegetables eaten raw or lightly cooked, such as in salads • Avoid for root crops such as carrots, since pathogens accumulate in the topsoil and in the roots • Irrigation carried out under plastic sheeting or buried under the soil surface significantly reduces crop risks, but microbial contamination still persists • Survival of E. coli O157:H7 was greatest in soil under rooted grass - moderate decline occurred only after 130 days. Edible crops should only be irrigated with greywater when risk of disease becomes less than the risk of hunger. 33
34 Reuse of greywater already happens Different liability when officially sanctioned - when initiated by citizens themselves they carry the risk 34
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