Quality of harvested rainwater and application of point of use. WRC 2014.

The main aim of this project was to determine the microbiological and chemical quality of harvested rainwater and people's perceptions on the use of rainwater. In addition this study was aimed at evaluating options for treatment of the collected rainwater. First the microbiological and chemical quality of rainwater collected in existing DRWH tanks was determined. Rainwater samples were collected from domestic rainwater harvesting tanks (DRWH) in a sustainable housing development in Kleinmond, South Africa. Water samples were collected on eight occasions from 29 tanks during the period of March to August 2012. The chemical and microbial parameters were compared to drinking water standards stipulated by the South African and Australian Quality Guidelines. A survey of users perceptions on rainwater harvesting was conducted. The social research project was aimed at developing a better understanding of public perceptions, including the degree of acceptance of DRWH, and the way in which the harvested rainwater is utilised. More specifically, quantitative and qualitative data were collected in order to describe the following: (1) the condition of the tank; (2) the users’ knowledge of the DRWH system, including its operation and maintenance; (3) whether the user would be willing to pay for repairs (if required); (4) perceived benefits and risks associated with DRWH; (5) level of satisfaction with DRWH; (6) and views on municipal water. In addition, demographic data on the respondents were gathered, viz. gender, age, highest level of education, household size and employment status, in order to provide a socio-economic background description of the study population. Finally, different point of use treatment systems (mainly filtration and solar pasteurization systems) were evaluated for their effectiveness in treating the harvested rainwater to produce water that meets drinking water quality standards.

Authors: Dobrowksy P.H.; van Deventer A.; Lombard M.; De Kwaadsteniet M.; Khan S. & Cloete T.E.

Organisations: Stellenbosch University; Water Research Commission

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The impact of wastewater irrigation by wineries on soils, crop growth and product quality. WRC 2014.

Winery wastewater should be treated to specific quality standards, where after it could be stored in irrigation dams, and used for irrigation of crops. Until now, the impact of this practice has, however, not been studied comprehensively. Thus, to know the impact of irrigating with winery wastewater on the chemical composition and physical structure of the soil, grapevine performance, and wine quality, is indispensable. It is envisaged that irrigating vineyards with irrigation water with added winery wastewater might alter the wine character and overall quality, compared to vineyards irrigated with raw irrigation water. In this regard, a research project to investigate the possible use of augmented winery wastewater for vineyard irrigation was initiated and funded by the Water Research Commission with co-funding by Winetech. The general objective of the project was to investigate the sustainable use of winery wastewater for irrigation of vineyards with respect to the effect on soils, vineyard performance and wine quality. The project was a multidisciplinary study which evaluated the impact of augmented winery wastewater on soils, vineyard performance and wine quality, if any, due to poor water quality as the main objective. The possibility of re-cycling winery wastewater for vineyard irrigation was investigated in a field trial near Rawsonville in the Breede River Valley.

Authors: Myburgh P.A. & Howell C.L.

Organisations: ARC

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Modelling the Fate of Pesticides: Primary Processes, Non-Point Source Data Collection and Guidelines. WRC 2012.

This project developed an integrated modeling approach to the prediction of agricultural NPS pollution from field- to catchment-scale for phosphorous, nitrogen, pesticides and sediments. A project team consisting of four individual Task Teams, comprising of one or more specialists within each of the domains of agricultural nutrients, sediments, pesticides, field-scale bio-physical modelling, catchment-scale bio-physical modelling, and agricultural economics, report on their activities in a series of five reports, namely: • WRC Report No TT 516/12 entitled Modelling Agricultural Non-Point Source Pollution and Economic-Environmental Trade-offs of Control Measures. • WRC Report No 1516/1/12 entitled Modelling Nitrogen and Phosphorus Dynamics in Cropping Systems at the Field Scale. • WRC Report No 1516/2/12 Modelling the Fate of Pesticides: Primary Processes, Non-Point Source Data Collection and Guidelines • WRC Report No 1516/3/12 Modelling Nutrient and Sediment Dynamics at the Catchment Scale • WRC Report No 1516/4/12 Modelling Economic-Environmental Trade-Offs of Agricultural Non-Point Source Pollution Control Measures.

Authors: Jovanovic N.Z.; Petersen C.; Bugan R.D.H. & van der Walt E.

Organisations: ARC - Plant Protection Research Institute; CSIR Natural Resources and the Environment

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Modelling economic-environmental trade-offs of Agricultural non-point source pollution control measures. WRC 2012.

This project developed an integrated modeling approach to the prediction of agricultural NPS pollution from field- to catchment-scale for phosphorous, nitrogen, pesticides and sediments. A project team consisting of four individual Task Teams, comprising of one or more specialists within each of the domains of agricultural nutrients, sediments, pesticides, field-scale bio-physical modelling, catchment-scale bio-physical modelling, and agricultural economics, report on their activities in a series of five reports, namely: • WRC Report No TT 516/12 entitled Modelling Agricultural Non-Point Source Pollution and Economic-Environmental Trade-offs of Control Measures. • WRC Report No 1516/1/12 entitled Modelling Nitrogen and Phosphorus Dynamics in Cropping Systems at the Field Scale. • WRC Report No 1516/2/12 Modelling the Fate of Pesticides: Primary Processes, Non-Point Source Data Collection and Guidelines • WRC Report No 1516/3/12 Modelling Nutrient and Sediment Dynamics at the Catchment Scale • WRC Report No 1516/4/12 Modelling Economic-Environmental Trade-Offs of Agricultural Non-Point Source Pollution Control Measures.

Authors: Matthews N.; Grové B. & Görgens A.H.M.

Organisations: University of Free State, department of Agricultural Economics; Aurecon

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Sustainable use of greywater in small-scale Agriculture and gardens in South Africa. WRC 2010.

This project was undertaken to provide guidance regarding the conditions under which greywater use should be allowed or propagated and to provide guidance to users about its sustainable use in small-scale agriculture and gardens. Two main products were produced, viz a user friendly Guidance Document and a supporting Technical Background Document which captures the technical information on which the Guidance Document is based and describes the extensive process that was followed to develop the Guidance Document. The Guidance Document is aimed at Municipalities, NGOs and informed members of the public who wish to implement greywater irrigation. The focus of the Guidance Document is to minimise the risks of • illness in handlers of greywater and greywater-irrigated produce, or consumers of greywater-irrigated produce. • reduction in growth or yield of plants/crops irrigated with greywater. • environmental degradation, especially reduction in the ability of soil irrigated with greywater to support plant growth.

Authors: Rodda N.; Carden K. & Armitage N.

Organizations: University of Cape Town; University of KwaZuIu-Natal

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Rapid enzymatic detection of organochlorine pesticides in water. WRC 2010.

Interest in environmental issues has highlighted the problem of pesticides in the environment, prompting a need for effective methods of detection. Pesticides detected in water and sediments include pyrethroids, organochlorines (DDT, DDE), organophosphates and carbamates. Current methods can offer detection; however, they have limitations. Enzymatic methods offer a simpler, more rapid and cost effective alternative. Enzyme inhibition by pesticides can be monitored using assays, the degree of inhibition being proportional to the concentration of pesticide. Such enzymes include alkaline phosphatases (ALP). However, only a limited number of contaminants have been tested using enzymatic methods and there is therefore a need to determine the effect of a range of contaminants on enzyme activity. This study showed that ALP was not an effective target for a biosensor for pesticides, however Cd, Hg, Ni and Zn were investigated and had a dramatic effect on the ALP, increasing its relative activity by 200% even at low concentrations. ALP activity was enhanced in the presence of environmental samples (Eastern Cape rivers), indicating the potential presence of metal ions. Therefore ALP is more suitable as an target for the detection and monitoring of metals in water.

Authors: Pletschke B.; Cockburn .; Adebiyi P. & van Dyk J.S.

Organisations: Rhodes University

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Predicting the environmental impact and sustainability of irrigation with coal mine water. WRC 2007.

Mining in South Africa generates large volumes of mine wastewater that have the potential to adversely affect an already scarce water resource if not properly managed (Tanner et al., 1999). The type of wastewater emanating from mines depends largely on the chemical properties of the geological materials that come into contact with the water (Thompson, 1980). The concentrations of salts and other constituents frequently render such waters unsuitable for direct discharge to the river systems, except in periods of high rainfall when adequate dilution capacity is present and controlled release is permitted by the regulatory authorities (Pulles et al., 1996). Mine water treatment is a possible solution to prevent or minimize the pollution of water resources. However, it has become very expensive to treat the water to a condition acceptable for release into natural watercourses.

Authors: Annandale J.G.; Beletse Y.G.; De Jager P.C.; Jovanovic N.Z.; Steyn J.M.; Benadé N.; Lorentz S.A.; Hodgson F.D.I.; Usher B.; Vermeulen D. & Aken M.E.

Organisations: University of Pretoria, University of KwaZulu-Natal; Institute for Ground water Studies; University of the Free State; Anglo Coal Environmental Services

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