Research Status And Control Methods For Chlorine-Containing Disinfection By Products In Small And Medium Water Plants

During the process of disinfection in drinking water treatment plant(DWTP),disinfectant can reacts with organic matters to generate disinfection by-products(DBPs)This paper investigated 111 small and medium-sized water plants in China to explore the formation and standard-exceeding risk of DBPs,and put forward improvement countermeasures according to the problems found in the investigation process.This paper investigated DWTPs in different river basins and regions,and explored the formation and standard-exceeding risk of DBPs in treated water.The results showed that the DBPs standard-exceeding phenomenon in some DWTPs caused by the deterioration of raw water.Among them,chlorine disinfection DWTPs formed high level DBPs in the Huai River and the Pearl River,and in South China and Southwest China,and trichloromethane,chloral hydrate and trichloroacetic acid showed standard-exceeding phenomenon.Chlorine dioxide disinfection DWTPs formed high level chlorite and chlorate in the Pearl River,the Yangtze River and the Huai River Basin,and in the Central China,South China and Southwest China.In order to deal with the standard-exceeding problems,this study proposed the combined technology of pre-oxidation treatment process and enhanced conventional treatment process,and investigated the control effect on the DBPs formation.The enhanced conventional treatment process optimized the operation parameters of coagulation and filtration process,which improved the control effect of trihalomethane,haloacetic acid and chloral hydrate by 45.4%,38.2%and 31.7%.Compared with the ozone and hydrogen peroxide pre-oxidation,the combined process of permanganate pre-oxidation and enhanced conventional treatment process has the best control effect on the formation potential of trihalomethanes,haloacetic acids and chloral hydrate,the removal rates reached 62.3%,61.0%and 45.8%,respectively.In this study,the feasibility of the combined process applied in the DWTPs was verified by investigating the small and medium-sized DWTPs which adopted the combined process.The results showed that the DWTPs can well cope with the DBPs standard-exceeding phenomenon.The formation of trihalomethane,chloral hydrate,dichloroacetic acid and trichloroacetic acid in the treated water of A DWTP were reduced by 28.2%,50.0%,11.1%and 36.4%,and the formation of chlorite and chlorate in D DWTP were reduced by 16.2%and 21.1%.