挥发性溴代消毒副产物在不同水处理工艺过程中的变化

Variation of volatile brominated disinfection by-products in different drinking water treatment processes

对中国沿海某市2个自来水厂的常规和深度水处理工艺过程中挥发性溴代消毒副产物的变化规律进行了研究。在选取的7种挥发性溴代消毒副产物中,只有一溴二氯甲烷、二溴一氯甲烷、二溴甲烷和三溴甲烷这4种被检出,除二溴甲烷只在深度水处理工艺过程中被检出外,其余3种化合物在2种不同水处理工艺过程中均有检出。一溴二氯甲烷和二溴一氯甲烷在常规和深度水处理工艺过程中的部分工艺段出水中的检出浓度超过了GB 5749-2006中规定的限值(饮用水中一溴二氯甲烷和二溴一氯甲烷的的浓度限值分别为60μg·L^(-1)和100μg·L^(-1)),应被给予足够的重视。挥发性溴代消毒副产物在常规水处理工艺过程中的检出浓度随水处理工艺流程而逐渐升高,而在深度水处理工艺过程中检出的挥发性溴代消毒副产物(除二溴甲烷外)浓度变化则表现为随水处理工艺流程先轻微降低后大幅升高的趋势。与常规水处理工艺相比,挥发性溴代消毒副产物在深度水处理工艺过程中的检出浓度明显低于其在常规水处理工艺过程中对应工艺段出水中的检出浓度,但对于在常规和深度水处理工艺过程中均被检出的3种挥发性溴代消毒副产物来说,它们的最大值均出现在加氯后出厂水中。

Occurrence and variation of volatile brominated disinfection by-products in conventional and advanced water treatment processes from two drinking water plants in a coastal city in China were studied.Among seven target compounds,only four compounds （bromodichloromethane,dibromochloromethane,dibromomethane and bromoform） were detected.Dibromomethane was only detected in the advanced water treatment process,and the other three compounds were detected in both conventional and advanced water treatment processes.Bromodichloromethane and dibromochloromethane were the prevalent contaminants in both water treatment processes and their concentrations in effluents of some treatment units exceeded the GB 5749-2006 standard limits （60 μg·L^-1 for bromodichloromethane and 100 μg·L^-1 for dibromochloromethane） and should be given sufficient attention in water treatment processes.The concentrations of volatile brominated disinfection by-products in conventional water treatment process gradually increased,while the concentrations of volatile brominated disinfection by-products （except dibromomethane） in advanced water treatment process decreased slightly and then increased significantly.Compared with the conventional water treatment process,the concentrations of volatile brominated disinfection by-products in the advanced water treatment process were obviously lower than those in the conventional wa-ter treatment process.However,for the three volatile brominated disinfection by-products detected in both water treatment processes,their highest concentrations were found in the effluents after chlorination.