二级出水中亚硝胺类消毒副产物分布及臭氧化特性

在污水深度处理过程中，臭氧氧化通常用来去除二级出水中的难降解有机物，提高后续深度处理工艺的处理效率。针对臭氧氧化对二级出水中亚硝胺类消毒副产物的作用，以城市污水厂二级出水为研究对象，采用固相萃取及超高效液相串联三重四级杆质谱联用仪作为分析测试手段，对二级出水中亚硝胺类消毒副产物的分布及臭氧化特性进行研究。结果表明，二级出水中7种亚硝胺类物质浓度由大到小依次为NPYR、NDIP、NDBA、NDMA、NMEA、NDPA和NDEA，均值分别为250、45.96、31.17、28、4.92、4.71和2.15 ng·L-1。随着臭氧投加量的提升，臭氧氧化会使二级出水中的亚硝胺类物质含量增加，特别是NPYR、NDIP、NDBA和NDMA 4种物质；但亚硝胺类物质的生成势却随之降低，且在臭氧氧化作用下亚硝胺的生成势降低量明显高于其自身的增加量，臭氧投加量越大，二者之间的差异越明显。臭氧氧化导致亚硝胺生成势的降低作用可以减少后续深度处理工艺及消毒过程中该类物质的生成，有利于保障再生水的回用安全。

Distribution and ozonation characteristics of nitrosamines in wastewater treatment plant effluent

Ozonation is usually applied to remove refractory organic matter from wastewater treatment plant (WWTP) effluent during wastewater reclamation, and improve the efficiency of downstream treatment process. Because of the effect of ozonation on nitrosamine disinfection by-products formation in WWTP effluent, the distribution and ozonation characteristics of nitrosamine disinfection by-products were investigated using solid phase extraction and UPLC MS/MS. The results show average concentrations of NPYR 250 ng·L-1, NDIP 45.96 ng·L-1, NDBA 31.17 ng·L-1, NDMA 28 ng·L-1, NMEA 4.92 ng·L-1, NDPA 4.71 ng·L-1 and NDEA 2.15 ng·L-1 in the WWTP effluent. Furthermore, although ozone oxidation can increase the concentrations of nitrosamines in WWTP effluents, especially NPYR, NDIP, NDBA and NDMA, the nitrosamine formation potential decreases with the increase of ozone dosage. Moreover, the magnitude of reduction of the nitrosamine formation potential was more significant than its further increment. The difference between these two effects is more notable at high ozone dosages. Thus, ozonation can enhance the removal of the nitrosamine formation potential, which can reduce the formation of nitrosamine disinfection by-products during downstream advanced and disinfection processes to guarantee the safety of the reclaimed water.