Optimizing Dosage and Location of Chlorine Injection in Water Supply Networks

Disinfection of the water in the drinking water supply network is usually done by injecting chlorine to the treated water before it is pumped into the network for distribution. However, such an injection process may not be sufficient to ensure that the chlorine residual throughout the network is within the standard limits. Usually, the residual chlorine is reduced as water moves through the pipe network, due mainly to its reaction with a variety of materials in the bulk water and from the pipe wall. Reduction in residual chlorine in the water supply network may lead to degradation of water quality and, thus, poses potential microbial risks to humans. To meet water quality standards, it is recommended to maintain residual chlorine throughout the water supply network within the desirable levels. This paper presents an optimization model based on the hydraulic simulation model (EPANET) and mixed integer linear programming technique for optimal locations and scheduling of booster chlorination in a real water supply network located in Al-Khobar, Saudi Arabia. The results demonstrate better performance with reduced doses of chlorine when booster chlorination is applied to the water distribution network. The findings may assist in reducing chlorine doses, which is likely to reduce human exposure to potentially harmful disinfection by-products in drinking water.