A Hybrid PSO for Optimizing Locations of Booster Chlorination Stations in Water Distribution Systems

Free chlorine residual needs to be maintained in the specified range (between minimum and maximum) in water distribution systems to avoid deterioration of the microbial quality of water, control taste and/or odor problems, and hinder formation of carcinogenic disinfection by-product. Booster chlorination is the addition of chlorine at locations distributed in water networks to maintain the chlorine residuals within a specified range throughout the distribution system. A notion of partial coverage is introduced for locating optimal booster chlorination stations in water distribution systems. It assumes that the water quality at a particular upstream node could be partially inferred by the water sampled at some downstream nodes if it delivers the proportions of water to the sampled nodes that are between the minimum coverage criteria and maximum coverage criteria. An optimization model is formulated in the presence of partial coverage based on the maximum covering location problem. A hybrid PSO, combined with GA algorithms, is proposed to get the solution. The new methodology is then applied to a hypothetical network. The results show that the hybrid PSO has substantial effect on the solution of the location of booster chlorination in water distribution systems.