Combined sewer overflows (CSOs) introduce microbial contaminants into the receiving water bodies, thereby posing risks to public health. This study systematically investigated the disinfection performance and mechanisms of the combined process of ultraviolet and peracetic acid (UV/PAA) in CSOs with selecting () as a target microbial contaminant. The UV/PAA process exhibited superior performance in inactivating in simulated CSOs compared with UV, PAA, and UV/HO processes. Increasing the PAA dosage greatly enhanced the disinfection efficiency, while turbidity and organic matter hindered the inactivation performance. Singlet oxygen (O), hydroxyl (OH) and organic radicals (RO) contributed to the inactivation of , with OH and RO playing the prominent role. Variations of intracellular reactive oxygen species, malondialdehyde, enzymes activities, DNA contents and biochemical compositions of cells suggested that UV/PAA primarily caused oxidative damage to intracellular molecules rather than the damage to the lipids of the cell membrane, therefore effectively limited the regrowth of . Additionally, the UV/PAA process displayed an outstanding performance in disinfecting actual raw CSOs, achieving a 2.90-log inactivation of total bacteria after reaction for 4 min. These results highlighted the practical applicability and effectiveness of the UV/PAA process in the disinfection of CSOs.

中文翻译：

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通过细胞内氧化作用，利用紫外线/过氧乙酸对合流下水道溢流进行有效消毒，同时保持细胞完整性


合流下水道溢流 (CSO) 将微生物污染物引入受纳水体，从而对公众健康构成风险。本研究系统地研究了紫外线和过氧乙酸（UV/PAA）联合过程在CSO中的消毒性能和机理，并选择（）作为目标微生物污染物。与 UV、PAA 和 UV/H2O 工艺相比，UV/PAA 工艺在模拟 CSO 中表现出优异的灭活性能。增加PAA用量大大提高了消毒效率，而浊度和有机物则阻碍了灭活性能。单线态氧 (O)、羟基 (OH) 和有机自由基 (RO) 导致 的失活，其中 OH 和 RO 起重要作用。细胞内活性氧、丙二醛、酶活性、DNA含量和生化成分的变化表明，UV/PAA主要对细胞内分子造成氧化损伤，而不是对细胞膜脂质的损伤，从而有效限制了细胞的再生。此外，UV/PAA 工艺在对实际原始 CSO 进行消毒方面表现出出色的性能，反应 4 分钟后总细菌灭活率达到 2.90 个对数。这些结果凸显了 UV/PAA 工艺在 CSO 消毒中的实际适用性和有效性。