Research On Formation Of Disinfection By-Products In Ozone Oxidation Of Drinking Water

Traditional water treatment process couldn’t meet the needs of the new Living and Drinking Water Hygiene Quality, due to more and more deteriorative water quality in our country,. Ozone-Biological Activated Carbon (O3-BAC) process is by far one of the most popular treatment technologies used in drinking water treatment. Especially, when the source of water comes from surface water, its efficiency becomes more outstanding than that of traditional drinking water treatment. On the other hand, at highly concentrated bromide in the source water, ozonation process will form the bromide, and brominated disinfection byproducts (Br-DBPs), showing higher toxicity than that of chlorinated disinfection byproducts (Cl-DBPs). Therefore, it is with great significance studying the DBPs formation in the ozone oxidiation of bromide-containing water.The research includes two stages. The first stage is static test performing in the lab. Trihalomethanes and haloacetic acids formation potential concentration and evolution are investigated at different operating conditions (ozone concentration and bromide dosage). The second stage is demonstration project performance in a water plant. Conventional water quality indexes and disinfection byproducts potential (DBPFP) were detected in the effluent of each structure under different operating conditions. Contrast with the traditional process in the same plant shows the effect of ozone and BAC. And by comparison of six working condition, the optimal condition has been determined.The results of the study show that:(1) In laboratory static tests, THMs and HA As formation potential first increase and then decrease along with increasing ozone dosage. When the ozone dosage is2.0mg/L, THMs and HAAs formation potential reach the maximum level.(2) As bromide ion concentration gradually increases in water, the bromo-DBPs production ratio also increases.(3) In water plant, at low ozone dosage (2.0mg/L) bromate production has not exceeded under this condition (10ug/L), and turbidity and organic matter could be well removed.(4) In demonstration project, good inhibition for total THMs and HAAs formation is obtained, while Br-DBPs is not effective controlled. In addition, the O3/H2O2, one of advanced oxidation technologies, is used for the controlling of HAAs and THMs formation, and shows better efficiency for HAAs formation than that of THMs.(5) In comparison with traditional process in the water plant, O3-BAC process shows lower Chlorine demand, THMs and HAAs formation in the effluent.