EXPERIMENTAL OBSERVATION ON EFFICACY OF BROMOCHLOROHYDANTOIN AND CHLORINE DIOXIDE IN DISINFECTION OF DRINKING WATER

In order to know the efficacy of chlorine dioxide and bromochlorohydantoin in disinfection of water and its influencing factors, quantitative germicidal test was carried out. Results: The disinfectant solution containing 0.3 mg/L chlorine dioxide with a 10 min contact time, chlorine dioxide disinfection powder solution with a 20 min contact time and bromochlorohydantoin solution containing available chlorine (bromine) 1 mg/L with a 10 min contact time reduced Escherichia coli contaminating the water to 0 cfu/100ml. The disinfectant solution containing chlorine dioxide 5 mg/L with a 20 min contact time, chlorine dioxide disinfection powder solution with a 10 min contact time and bromochlorohydantoin solution containing available chlorine (bromine) 3 mg/L with a 20 min contact time could reduce coli-group in natural water sample to 0 cfu/100ml. Within the range of the test, the germicidal efficacy of the three disinfectants decreased with decreasing temperature and increasing pH value and organic substance concentration. Conclusion: The 2 chlorine dioxide preparations and bromochlorohydantoin have good efficacy in killing coli-group in drinking water.