AAO工艺联合臭氧削减污水中微量有机污染物及遗传毒性

近年来,微量有机污染物(OMPs)的环境赋存及风险越来越受到学者的重视,而城市污水厂出水作为向水环境释放OMPs的重要污染源,应被加以监测和管控.以小试厌氧/缺氧/好氧工艺联合臭氧(AAO-O_3)为研究对象,考察了污水中14种OMPs在组合工艺中的迁移转化规律及遗传毒性的削减.结果表明,活性污泥系统对于大多数OMPs的去除效果不佳,去除率低于50%,而后续臭氧可以弥补其不足.AAO-O_3组合工艺可以保证多数OMPs去除率在90%以上.芳香性结构的取代基中含有酚羟基(—OH)、胺基(—NH2)、甲氧基(—OCH3)的OMPs易于在臭氧过程中降解.遗传毒性结果表明,污水和二级出水都存在一定致突变风险,二级出水经过臭氧处理之后,遗传毒性去除率达到98%,污水厂出水对水环境风险大大降低.

Reduction of Wastewater Organic Micro-pollutants and Genotoxicity in a Hybrid Process Involving Anaerobic-anoxic-oxic and Ozonation Treatments

In recent years, researchers have drawn greater attention to the occurrence, fate, and risk of organic micro-pollutants (OMPs) in the environment. Effluent from municipal wastewater treatment plants (WWTPs) are an important source for the release of OMPs into aquatic environment and should be monitored and controlled. The migration and transformation of 14 selected OMPs and their reduction of genotoxicity after treatment by a hybrid process of anaerobic-anoxic-oxic (AAO) and ozonation were investigated. Results showed that the activated sludge process was poor in removing most OMPs, with removal rates of less than 50%. However, ozonation improved OMPs removal, and the hybrid process could reduce most of the OMPs by more than 90%-with OMPs containing phenolic, aniline, and anisole groups in their aromatic structures showing particular vulnerability to attack by ozone. The results of genotoxicity analyses showed that the wastewater influent and secondary effluent exhibited genotoxicity to an extent, and ozonation reduced the genotoxicity of secondary effluent by 98%, thus largely reducing the environmental risk posed by OMPs in WWTP effluent.