AlternativeAlternativeWater Supply -Water Supply -A Water ServicesA Water ServicesPerspectivePerspective PortfolioPortfolioCommitteeCommittee

14 September 200514 September 2005

DEPARTMENT: WATER AFFAIRS AND FORESTRYDEPARTMENT: WATER AFFAIRS AND FORESTRY

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.

Why Alternative supply?

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 affordable where

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 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•

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 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