Prediction of chlorine concentration in various hydraulic conditions for a pilot scale water distribution system

Chlorine compounds are widely used in water distribution systems to prevent waterborne diseases. Maintaining a sustainable level of residual chlorine in domestic tap water is important to ensure the quality of drinking water. In this study, we designed and fabricated a pilot-scale water distribution system to explore the relationship between the hydraulic conditions and the temporal variation in chlorine concentration. Various hydraulic conditions were introduced during operation, and temporal variations in chlorine concentration were recorded. The existing chlorine models that are used for water distribution systems can be categorized into three distinct groups. A genetic algorithm was used to calibrate the parameters of the various models and hydraulics. Regression analysis under turbulent conditions indicated that the fitted parameters from several chlorine models significantly were correlated with Reynolds numbers. The parameter space of several chlorine decay models was configured in conjunction with the hydraulic condition, and parameters were modeled under various flow conditions. Validation of the chlorine decay models under turbulent flow condition (Reynolds numbers of 15,000-40,000) showed good agreement (R² > 0.8) with the experimental observations obtained from the pilot plant system.