Impact of Optimized Pump Scheduling on Water Quality in Distribution Systems

Abstract

Pump scheduling can improve performance of water supply systems, but it may have a different effect on water quality. The target of this article is to examine optimized pump schedules’ impact on water quality. EPANET’s quality simulator is applied for modeling water age and chlorine residuals through extended period simulations within two distribution networks: optimized and nonoptimized pumps. Results indicate that optimized pumps, in our case study, can improve water quality in and around the storage tank because they produce shorter tank filling and emptying, but they increase water retention time and reduce disinfectant residuals within most network pipes. Leakage can cause some pipes in the optimized network to have chlorine concentrations under the standard level (0.2 mg/L). In addition, the average rate of chlorine decay for the optimized system (36%) is faster than that of the nonoptimized one (33%) when a reactive contaminant is considered. Overall, these results indicate that hydraulic benefits and water quality must be considered together for pump scheduling problems.