Chlorine Decay Simulation in Water Distribution System Using EPANET

Abstract

Chlorine is used as a disinfectant in the water treatment process so that treated water is delivered safely to consumers. However, chlorine concentration decays when water flows from the treatment plant to the supply point, due to the reaction with natural organic matter and the inner surface of the pipe. Low chlorine concentration may encourage bacteria re-growth, while high chlorine concentration can result in the formation of harmful chemical components. Therefore, this study aims to simulate the complex process of chlorine decay using EPANET. This exercise enables the determination the chlorine concentration dosage required to maintain the desired requirement given by the World Health Organization (WHO) and the Ministry of Health, Malaysia (MOH). A successful model with an extended period of simulations of 72 hours enable the mapping of spatial and temporal variations of flow and residue chlorine concentrations at all links and nodes. Constant chlorine dosage of 3.96 mg/l at node R1 has successfully satisfy the requirement given by WHO and MOH. The residue chlorine concentrations at the nodes and links in the water distribution system also depends on the water usage at node 5, the size of service reservoir and service tank and distance from the reservoir.

Chlorine Decay Simulation in Real Water Distribution System Using Epanet Program

“…This software has been utilized by several researchers since the 1990s to estimate the amount of chlorine that remains in the water distribution system after chlorination. The EPANET software is developed based on the basic principles of energy conservation and continuity equations, where continuity equations show that the algebraic sum of the flow rate in a pipe meeting at a node along with any external flow is zero [23].…”