Factors affecting the formation of DBPs by chlorine disinfection in water distribution system

Abstract

Chlorine is the most commonly used disinfectant in drinking water treatment plants in China. It reacts with natural and anthropogenic organic pollutants in the water distribution system, result-ing in the formation of carcinogenic disinfection by-products (DBPs). In this study, the influences of residence time, pH, chlorine dosage, water temperature, bromide concentration, and pipe material on the formation of DBPs in the water distribution system were investigated. Studies and observations showed that the formation of trihalomethanes (THMs) and haloacetic acids (HAAs) was positively correlated with residence time, chlorine dosage, water temperature, and bromide concentration during the chlorine disinfection, and the main generated DBPs were determined to be dichloro-acetic acid, trichloroacetic acid, and trichloromethane. With the increase of bromide concentration, the generation of Br-DBPs substantially increased. Elevating solution pH posed a promoting effect on THMs production, while exerted an inhibitory effect on HAAs formation. The generation of THMs and HAAs in the water supply network was also affected by pipe material, and the production level followed the order of plastic steel pipe > ductile iron pipe > PE pipe. Through exploring different influencing factors, it provides a reference for the control strategy of DBPs in the water supply network and achieves the purpose of realizing the residents’ drinking water safety.