Use of Optimization Technique for Optimal Scheduling of Booster Chlorination in Drinking Water Distribution Systems

Abstract

Chlorine concentration is an important parameter used to assess the quality of water supplied by a distribution network. in contrast to conventional methods that apply disinfectant only at the treatment works or source, booster disinfection reapplies disinfectant at strategic locations within the distribution system to compensate for the losses that occur as it decays over time. Booster disinfection strategy can reduce the mass of disinfectant required to maintain a detectable residual at points of consumption in the distribution system, which may lead to reduced formation of disinfectant by products such as Trihalomethanes also. The aim of present study is to formulate an optimization model using Liner Programming in Excel by coupling the results of residual chlorine obtained using EPANET software for selection of location of Booster chlorination stations as well as to optimize the Chlorine mass rate injections for the steady state flow conditions. Results from application of the formulated model suggest that schedule minimizes the total dose required to satisfy residual constraints of 0.2 mg/L (IS 10500-1991) at all the locations within distribution network as compared to conventional chlorination in which chlorine is applied at source only. The use of optimization method to select the scheduling of Booster stations can be used as the decision-making tool for the water supply authority for the selection of location and number of booster station along with the application of chlorine mass rate to maintain the residual chlorine as 0.2 mg/ L at all the locations in Drinking Water Distribution system.