The Use of Different Chlorine Decay Models in Different Materials of Pipelines in Water Distribution System

Abstract

There are four kinds of chlorine decay models used in water distribution system: Traditional Pseudo-first-order Reaction Model, Two-order Model, Two-stage Model and First-order Model based on the mass transmission. They've got respective form when modeling the residuals of chlorine. This study used water distribution system in a city of North China as object, with the water information itself, comparing the wall constant (kw) of ordinary cast iron pipes, nodular cast iron pipes, stainless steel pipes and polyvinyl chloride (PVC) pipes to analyze the influence of different materials of pipelines. The results showed that pipe material significantly influenced chlorine decay rates in the following order: ordinary cast iron > nodular cast iron > polyvinyl chloride (PVC)> stainless steel. Meanwhile, this paper emphasized more appropriate chlorine decay models applying to different pipe materials. Based on this, this paper also pointed out that choosing a more reasonable residual chlorine model, combined with the local water distribution system conditions, should also benefit water quality monitoring and regulation.