污水处理厂不同紫外/氯化组合工艺的消毒效能对比

Comparison of Disinfection Efficiency of Different UV/Chlorination Combined Processes in Wastewater Treatment Plant

污水消毒对于保障生态和人体健康安全具有重要意义,特别是在近期新冠肺炎疫情的严峻形势下,污水消毒及安全排放备受关注。而一味通过提高消毒剂投加量来增强对致病微生物的杀灭效果,会导致高毒性消毒副产物(DBPs)产生量增加,从而对受纳水体带来新的安全风险。鉴于此,以上海市某城市污水处理厂二沉池出水为研究对象,进行了单独氯化、单独紫外、先紫外后氯化、紫外/氯化同时等不同消毒方法的对比分析。研究发现,先紫外后氯化消毒对粪大肠菌群具有更优的灭活效果,灭活率可达到100%,对几种潜在致病菌属的灭活效果最为均衡,并且DBPs生成量更低,其中高毒性二氯乙腈浓度仅为单独氯化和紫外/氯化同时消毒方式的50%左右,说明该方法在微生物灭活和DBPs协同控制方面具有显著优势。

Wastewater disinfection is of great significance to the protection of ecological and human health safety. Especially in the recent severe situation of COVID-19 epidemic, the wastewater disinfection and safe discharge have attracted much attention. However, blindly increasing the dosage of disinfectant to enhance the sterilization efficiency of pathogenic microorganisms will lead to an increase in the formation of highly toxic disinfection by-products(DBPs) and bring new safety risks to the receiving water bodies. The effluent samples from a secondary sedimentation tank of a wastewater treatment plant in Shanghai were disinfected by different methods including chlorination, UV, UV followed by chlorination and simultaneous UV and chlorination, and the disinfection performances were compared. The UV followed by chlorination disinfection had a higher inactivation rate of 100% for fecal coliforms, and its inactivation effects on several potential pathogenic bacteria were the most balanced. In addition, the yield of DBPs was lower, and the concentration of highly toxic dichloroacetonitrile was only about 50% of that of the chlorination disinfection and simultaneous UV and chlorination disinfection, indicating that the UV followed by chlorination disinfection method had significant advantages in the synergistic control of microbial inactivation and DBPs.