The Least Cost Design of Water Distribution Networks Using Water Quality Constraints

Water quality is a very important issue related to people health, but it is not usually considered in water distribution networks (WDNs) design. In this paper, new constraints such as free residual chlorine and the quality performance index are incorporated into the least cost design of water distribution networks. EPANET2 was applied for the hydraulic and quality analysis of water distribution networks. GA was also used to solve the optimization problem. The method was evaluated using a well-known test network. Results showed that inclusion of quality constraints leads to a higher cost. In addition, sensitivity analysis of velocity constraints showed that hydraulic and quality constraints are required for the least cost design of WDNs. On the other hand, the optimum design should satisfy the design criteria at both the start and end of the design period.