52 The Future of Water in African Cities
Box 2.7 (continued) Figure B2.7.1 Dual Benefits of Water Fit for Purpose: Reduced Consumption of Fresh Water and Reduced Wastewater Discharge Fresh water source
Fresh water supply
Wastewater from smallscale industry
Wastewater from Durban
MONDI Paper
Wastewater
Wastewater Treatment
Disposal of Wastewater
SAPREF
Refuse of water
Reclaimed Water
[7% (47.50 Ml/d) of city’s current demand]
[Reduction in wastewater discharge @10%]
Source: IWA Water Wiki, 2011.
The eThekwini Water Services developed a strategy to recycle wastewater as an additional water source. A wastewater treatment plant and a recycling plant provide reclaimed water that meets the water quality requirements of the primary clients (a paper mill and a refinery). At operational capacity, the reclamation plant meets 7 percent of Durban’s water demand and reduces the wastewater discharge by 10 percent. As a co-benefit, the industry customers reduce their costs by purchasing reclaimed water rather than high-quality potable water. Source: IWA Water Wiki, 2011.
Diverse Sources Provide Better Water Security Given shrinking water supplies, rising demand and cost, and uncertainty about the future, it is necessary to explore diverse and flexible options for water sources. A broader range of water sources increases the reliability and security of the water supply (Alcamo et al., 2008; Gleick, 2009). Groundwater is the most obvious source to supplement surface water, but other options such as stormwater, greywater, and blackwater should