污水生物与深度处理技术对新型含氮消毒副产物及前体物的控制

Study on the control of emerging nitrogenous disinfection by-products and precursors by biological and advanced treatment for wastewater reclamation

典型含氮消毒副产物(N-DBPs,包括亚硝胺、卤乙腈和三氯硝基甲烷)的控制是污水回用过程中需关注的重点.本研究对采用不同生物处理工艺的污水厂进行生化池进出水中N-DBPs的存在水平分析,并选取其中一个污水厂的二级出水进行不同深度处理(粉末活性炭吸附、臭氧氧化、高铁酸盐氧化、二氧化氯氧化),研究其对N-DBPs及其前体物的去除.结果表明,生物处理过程会导致亚硝胺的生成.深度处理工艺中,粉末活性炭会催化亚硝胺的生成,臭氧氧化则会直接生成亚硝胺.选择的深度处理工艺对亚硝胺前体物均有去除,其中粉末活性炭和二氧化氯对二甲基亚硝胺和总亚硝胺的控制效果较好.但氧化工艺对卤乙腈(HANs)和三氯硝基甲烷(TCNM)的前体物影响不一,高铁酸盐对两者的前体物均有显著去除,二氧化氯会增加污水在低浓度氯胺处理时HANs的生成,臭氧氧化则会增加TCNM在后氯胺化过程中的生成.研究结果推动了污水深度处理技术的发展并为相关研究提供了理论指导.

The control of typical nitrogenous disinfection by-products(N-DBPs, including nitrosamines, haloacetonitriles and trichloronitromethane) is a major concern in wastewater reuse. In this study, the presence levels of N-DBPs in the influent and effluent of biochemical treatment in wastewater treatment plants(WWTPs) with different biological treatment processes were analyzed.The secondary effluent of one of the WWTPs was selected to investigate the removal of N-DBPs and their precursors in different advanced treatments(powdered activated carbon adsorption, ozone oxidation, ferrate oxidation, and chlorine dioxide oxidation). The results showed that the biological treatment process resulted in the generation of nitrosamines. For the advanced treatment processes,powdered activated carbon(PAC) catalyzed the generation of nitrosamines, while ozone oxidation formed nitrosamines directly. The selected advanced treatment processes showed different degrees of removal of nitrosamine precursors, with PAC and chlorine dioxide providing better control of Nnitrosodimethylamine and total nitrosamines. However, the oxidation processes had mixed effects on the precursors of haloacetonitriles(HANs) and trichloronitromethane(TCNM). Ferrate(Fe VI)showed significant removal of precursors of both HANs and TCNM, while chlorine dioxide increased the formation of HANs in the effluent treated with low concentration of chloramine.Ozonation increased the generation of TCNM during post-chloramination. The results promote the development of advanced wastewater treatment technologies and provide theoretical guidance for related research.