Studies on DBPs and Bromate Control by Ozone Combined Processes in Drinking Water
|School||East China University of Science and Technology|
|Course||Environmental Science and Engineering|
|Keywords||disinfection ozone combined processes THMs HAAs bromate|
With the rapid development of social economy, the water pollution of downstream Huangpu River is becoming increasingly aggravated, which seriously threatens the safety of drinking water. The conventional process applied by one water supply plant in Shanghai to treat this water source had difficulty to meet the national standard change of water quality, and then the concentrations of DBPs. such as THMs and HAAs, exceeding the national standard frequently occurred during disinfection process. In this paper, the qualities of water source of downstream Huangpu River and effluent from pilot sand filtration were comprehensively evaluated, and the treatment effect of combined processes of O3-BAC and O3/H2O2-BAC on filtered water was systematicly studied. The conclusions were as follows:The monthly mean value of raw water DOC in second half year of 2010 was ranged from 4.90 to 5.31mg/L. Because the removal ability of the DBPs precursor by conventional pretreatment process was limited, the concertration range of DBPFP in filtered water was up from 250 to 330μg/L. It was indicated that ozone combined process had good effect on the removal of organic contaminants and DBPs precursor in filtered water through pilot test with half-year. The optimal dosage of O3 for O3-BAC process was 2.0mg/L and the removal efficiencies of DOC, UV254,THMFP and HAA5FP in carboned effluent were 41%.64%.36% and 47%, respectively. Moreover. O3/H2O2-BAC process promoted the removal efficiency of DBPFP further and the generated amount of bromate was also controlled effectively. The concertration of bromate in carboned effluent basically maintained at 1 to 2μg/L. With the optimal dosage of O3 and ratio of H2O2/O3 for this process were 2.0mg/L and 0.5. the removal efficiencies of DOC. UV254, THMFP and HAA5FP in carboned effluent were 52%,70%,51% and 55%, respectively.The pilot test results showed that the treatment effect of O3/H2O2-BAC process was better than that of O3-BAC process on whole. Consequently, the optimal process conditions of ozone combined process to the advanced treatment of downstream water in Huangpu River were confirmed that O3=2.0mg/L, H2O2/O3=0.5.