Planning Model for Wastewater Reuse System in South Africa

South Africa is a semi-arid country with limited freshwater resources. Growing urbanization, industrialization and agriculture have placed significant demands on this resource with Water Service Authorities and Providers continually striving to efficiently allocate and optimally manage this resource for the various sectors. A proven measure to help meet increasing demand is the reclamation of wastewater for non potable purposes. Reclaimed water can be used for landscape and garden irrigation, some industrial processes (e.g. cooling, and air conditioning), toilet flushing, dust suppression, some construction water requirements, fire fighting, and environmental enhancement (e.g. maintaining urban stream flows and wetlands). Urban reuse of reclaimed wastewater is often conveyed through a dual distribution system, which comprises one system of pipes for conveying potable water and a second system of pipes for conveying reclaimed water. A variety of dual system configurations currently exist internationally. Effective planning of the reuse system, which considers potential water source(s), the water supply and distribution system, water demand, end user characteristics, water quality requirements and wastewater treatment, should occur in conjunction with the overall urban water system. These planning elements may be integrated and will result in multiple interactions and a variety of design configurations. This paper presents a model for assessing the potential for reclaimed wastewater reuse within a typical South African urban water system.