Development of guidance for sustainable irrigation use of greywater in gardens and small-scale agriculture in South Africa

Abstract

Greywater is untreated household effluent from baths, showers, kitchen and hand-wash basins and laundry (i.e. all non-toilet uses). More than half of indoor household water is normally used for these purposes and can potentially be intercepted by the householder for additional beneficial uses. Greywater use is practised on an informal basis to supplement irrigation water, either in urban gardens in middle-to upper-income suburbs or in food gardens in lower-income informal, periurban and rural areas. It holds the potential to contribute significantly to food security in poor settlements by providing a source of both irrigation water and nutrients for crop plants. However, there are presently no formal guidelines for the use of greywater in South Africa. This paper presents the rationale and framework of a guidance document for the sustainable use of greywater to irrigate gardens and small-scale agriculture in South Africa, developed under the auspices of the Water Research Commission. The 3 driving principles in developing this guidance were: protection of human health; protection of plants irrigated; and protection of soil and the environment. Risk-management scenarios were developed on the basis of the extent of greywater characterisation. Water-quality constituents for inclusion were selected from among those indicated as presenting a problem in previous studies. Guidance was provided for managing greywater quality, either by mitigation of greywater quality (by practices such as irrigation method, amelioration of soil, leaching of soil and planting of tolerant plant types) or by small-scale biological treatment of greywater. Guidance was also given regarding the volumes of greywater which can be applied, together with factors to adjust these volumes for site-specific conditions.

Challenges and Opportunities for Sustainable Urban Farming in South African Low-Income Settlements: A Case Study in Durban

“…A study by Bakare et al [35] in a Durban community showed a greater willingness to use greywater for toilet flushing and garden purposes at times of drought or water scarcity, and predominantly among younger participants (20-to 29-years-old). Rodda et al [36] evaluated the impact of medium-term sub-surface irrigation of vegetable crops with domestic greywater on soil, plant growth and yield, and microbiological quality of crops. The study concluded that greywater irrigation increased plant growth and crop yield.…”

Supplementary household water sources to augment potable municipal supply in South Africa

“…Furthermore greywater is also a potential source of nutrients for plant growth, particularly for users who cannot afford fertiliser, and the soapy nature of greywater means that under some conditions it may act as a pest-repellent (Rodda et al, 2011). Greywater is, however, inherently variable in quality and as is most likely to be applied on a scale where quality monitoring is not feasible (Rodda et al, 2011). A range of contaminants may cause disease and have a negative impact on the environment.…”

Water security in South Africa: perceptions on public expectations and municipal obligations, governance and water re-use

“…Water re-use in both rural and urban environments is an essential strategy to overcome the looming water scarcity in South Africa (Ghunmi et al, 2011;Rodda et al, 2011); however, the data presented in Table 3 suggest that information on water re-use may not be filtering down to the public. Public awareness around water re-use and its necessity is essential since the threat of water insecurity is further complicated by the interdependency between water, energy and food production and consumption.…”