Analysis of disinfectant decay in a water supply system based on mathematical model

The purpose of the water supply system (WSS) is to provide best quality water to consumers. Water composition changes throughout whole WSS, including water production subsystem and water distribution subsystem (WDS) and is caused by variety of factors, that is, quality of raw water, efficiency of treatment method, and quality of the treated water feeding the pipe network. Additionally, water quality in the WDS depends on the following factors: way of storage and transport and technical condition of pipeline and domestic water installations. To ensure good microbiological water quality at every point of the system, water has to be disinfected. Changes in tap water quality should be monitored to undertake an effective precaution to minimize a risk of secondary microbial water contamination. However it is not possible to perform a continuous control of tap water parameters at WDS due to the size and structure of the water pipe network. For this reason, it is necessary to use mathematical models to simulate changes to quality parameters of water in WDS. In this work, three simulations of chlorine decay in the WDS were carried out. Collected data on chlorine decay were used in a special analysis to define areas of risk for secondary water contamination. Simulations were carried out using EPANET for Silesian region WSS.