中高氨氮浓度下黄浦江原水的加氯方式

Chlorination method of raw water from Huangpu river with medium-high concentration of ammonia nitrogen

上海闽行自来水公司第三水厂深度处理工艺后出水的氨氮质量浓度在0.5~1.5 mg/L之间，分别通过折点加氯消毒和氯胺消毒，比较管网运行24 h内的持续消毒效果、细菌灭活率、总有机碳（TOC）、三卤甲烷（THMs）、卤乙酸（HAAs）浓度随时间的变化规律，从而确定最佳消毒方式。实验结果表明：氯胺消毒后余氯的持续消毒效果远强于折点加氯消毒；氯胺消毒短时间杀菌效果虽弱于折点加氯消毒，但维持管网内的杀菌和抑制细菌增长的能力更强；24 h后两者TOC含量相差不大；折点加氯消毒后产生THMs的种类和浓度随时间递增，而氯胺消毒后仅产生三氯甲烷，大大降低了卤代甲烷类消毒副产物的生成量；2种消毒方式后产生的HAAs主要为二氯乙酸和三氯乙酸，占总HAAs的90%左右。

The average concentration of ammonia nitrogen is 0.5-1.5 mg/L in the effluent after the advanced treatment in the Third Water Works of Minhang Water Supply Company. In order to find the optimal disinfection method between break-point chlorination and chloramination, the lasting disinfection effect, bacterial inactivation rate, total organic carbon（TOC）, trihalomethane（THMs） and haloacetic acids（HAAs） within 24 h of pipe work were investigated. The results show that the chloramination has a stronger ability of maintaining sanitary protection throughout the water distribution system than break-point chlorination. The TOC is more or less the same by two disinfection methods after 24 h. The concentrations and kinds of the THMs grow with time after break-point chlorination. However, only trichloromethane is generated after chloramination, which greatly reduces the formation of THMs. The generated HAAs are mainly dichloroacetic acid and trichloroacetic acid after two disinfection methods, which account for about 90% of the total HAAs.