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Alternative Water Supply - A Water Services Perspective Portfolio Committee 14 September 2005. DEPARTMENT: WATER AFFAIRS AND FORESTRY. Why Alternative supply?. MIG Grant. At the retail or WS level, WSAs are increasing facing financial difficulties.
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Alternative Water Supply - A Water Services Perspective Portfolio Committee 14 September 2005 DEPARTMENT: WATER AFFAIRS AND FORESTRY
Why Alternative supply? MIG Grant • At the retail or WS level, WSAs are increasing facing financial difficulties. • Affordability of alternative supply mechanisms, rather than technical limitations are usually the problem. • Grants and improved cost recovery can only provide so much; there is thus a need to improve the efficiency of schemes. • This includes utilising alternative sources of water or means of accessing it and also the efficient use of water.
Desalination Although there are a number of methods, only two have really been used in SA. • Solar distillation • Requires much sunshine. • Has been done successfully at 2 schools (Kerkplaas and Algerynskraal) • Can be implemented in modules. • Appropriate only in very water scarce areas. • Reverse Osmosis • Expensive, but becoming affordablewhere electricity is available
Desalination • Reverse Osmosis (continued) • WRC study due for completion November 2005 • This system is used at Bushman’s River Mouth, Kenton-on-Sea and on Robben Island. • Where diesel generators are used for power, this method becomes very expensive and solar distillation is more appropriate. • There is a huge potential as sea water is unlimited.
Rainwater harvesting • Rainwater is collected from impermeable surfaces, usually a roof, and led to a storage tank. • Water can be passed through a screen and charcoal to purify it. • This technology is simple, there is a sense of ownership and no need to transport the water. • Rain is however unpredictable and large storage tanks may be necessary where the dry season is long. • Although widely used internationally, there has been little use in SA. Genadendal and Kammiesburg are examples. • This is a secondary supply of water, but can substantially reduce the stress on supplies.
Cloud/Mist harvesting • Water droplets are intercepted and collected on vertical panels of shade cloth or nylon mesh placed perpendicularly to the wind. • The droplets fall into gutters at the bottom and are fed into a storage tank. • This system is only suitable for mist prone areas such as mountains or coastlines with cold water. • Easy to construct and maintain • Unfortunately only small amounts of water are produced and the formation of mist is uncertain. • Pilots in SA on W. Coast, at Lepelfontein and in mountainous areas of Limpopo & E. Cape. • There is limited potential for this.
Grey water recycling • Grey water is water used for washing self, clothes & dishes. • Approximately 1500 households have been fitted with recycled mechanisms to irrigate their gardens. Genadendal is an example. • Whilst this will reduces the demand for irrigation water, there will be less returned into the system for downstream users, which may be problematic. • There can be social customs that prevent the use of washing water for gardens.
Water Conservation and Demand Management • Good WCDM practices can substantially reduce the water requirements with relatively little expense, (as was recently presented to you). More importantly they can be self funding. • WCDM deals with issues such as: • Technical aspects (Active & Passive Leakage Control, Water Audit & Mass Balance, Network Audit, Pressure Reduction etc) ; • Social aspects (Education & Awareness programs, etc); • Financial Aspects; and • Institutional & Legislative aspects (Bylaws, including WC/WDM in WSDP).
Other • Virtual Water • This entails growing crops in another country and then importing them back to SA. In essence we are using the other country’s water. • Reduction in evaporation from water in storage • This has been used in Namibia and although tested in SA, with mixed results, has not yet been applied.
Sanitation • Without going into details of sanitation, suffice to say that there are various water saving sanitation technologies. • Systems such as LOFLOS, urine diversion etc. • This can reduce water demand substantially, bearing in mind that one flush of a waterborne toilet can use 10 – 15 liters per flush.
Involvement of WSAs • DWAF is engaging with WSAs through the IDP/WSDP process. • This affords an opportunity to inform Council and officials of the various alternative options, so that they can make informed decisions. • This requires them to consider technical, social, financial and political imperatives. • It is essential that before implementing other options, that they have the capital and operating funds required, and can make allowance for replacement costs.
Involvement of WSAs • Most importantly the WSAs’ must have the capacity to operate and manage the systems. • What could also assist municipalities is to provide appropriate user-friendly guidelines. In this regard the “Guideline on small scale productive uses” currently being drafted will be of assistance. • Benchmarking and lesson sharing between municipalities will be valuable. THANKS