Combined Disinfection Process of Chlorine Dioxide and Chloramine in Drinking Water Treatment

Raw water was taken from the filtrated water of a waterworks in Tianjin and disinfected by the combined process of chlorine dioxide and chloramine.The variation of residual disinfectants within a given time after the combined disinfection with different dosages as well as the disinfection effect and the persistent disinfection ability of the combined process were investigated using chemical analysis and biological tests.After the combined disinfection with different dosages of chlorine dioxide and chlora-mines,the total bacteria and coliform counts can meet the requirement of the Standards for Drinking Wa-ter Quality.Chloramine dosage has a significant influence on total residual chlorine and residual chlorine dioxide,while chlorine dioxide dosage has not a significant influence on its residual quantity.The com-bined disinfection of chlorine dioxide and chloramine is effective and persistent when chlorine dioxide and chloramine are at low dosages.