Abstract:rination disinfection system upgrade project of a water plant in a national development zone in Jiangsuwas taken as the research object. Sodium hypochlorite was used instead of liquid chlorine as disinfect⁃ant. The disinfectant consumption, residual chlorine and disinfection by-products using liquid chlorineand sodium hypochlorite were compared. The results showed that there was no significant difference inthe effect of reducing turbidity and removing residual chlorine using these two disinfectants. With thesame treatment effect, the average chlorine consumption of sodium hypochlorite and liquid chlorine were14.71 kg/kt and 1.47 kg/kt, respectively. Disinfecting with liquid chlorine and sodium hypochlorite, themean values of THMs were 379 μg/L and 253 μg/L, respectively. Compared with liquid chlorine disin⁃fection, sodium hypochlorite disinfection process reduced the production of disinfection by-products. Close-