Optimal Design of Water Distribution System Considering Water Quality and Hydraulic Criteria Using Multi-objective Harmony Search

Abstract

AbstractThe objective of the water distribution system (WDS) is to supply water from sources to consumers with safe water quality, stable water quantity, and appropriate water pressure under normal as well as abnormal conditions. To satisfy these objectives, there is a minimum pressure required for each WDS. In addition, to supply safe water, the World Health Organization has stipulated that residual chlorine standards should be maintained at 0.2–5.0 mg/L. However, the change in residence time, pressure, and flow rate can affect the design factor depending on the usage pattern. Even if the network size of WDS is similar, the shape of WDS affects hydraulic and water quality characteristics, such as not meeting the minimum pressure required by WDS. Therefore, in this study, branched type, hybrid type, and looped type were classified to consider the types and size of WDS. The objective functions applied the maximum system resilience and the minimum design cost. The optimal solution compared with the optimal design considering only pressure as the constraint and the optimal design considering the pressure and residual chlorine concentration simultaneously. The derived optimal design will meet the system’s resilience and the economic, water quality, hydraulic aspects, and it will increase the usability of customers.KeywordsOptimal design of water distribution systemsMulti-objective harmony searchWater quality and hydraulic indices