Ozonation is an established process for advanced wastewater treatment, with a dose-dependent degree of disinfection. It is generally followed by biological post-treatment with the main objective of oxidation by-product abatement. However, there is little research on the impact of the combination of ozonation and biological post-treatment on microbiological quality parameters. This long-term study investigated pilot-scale ozonation with six different filtration processes (4 deep-bed filter systems and 2 vertical flow constructed wetlands) as biological post-treatment. A broad spectrum of microbial parameters has been monitored for a comprehensive evaluation of the disinfection performance. While vegetative bacteria (Escherichia coli and enterococci) were inactivated to a large extent by ozone, spore-forming Clostridium perfringens and viral indicator somatic coliphages exhibited a high ozone tolerance and could only be effectively retained in subsequent filtration steps. Extended hydraulic retention times as well as fine filter materials in post-treatment proved to be beneficial for faecal indicator abatement. In deep-bed filters, coagulant dosing was an additional important factor for the disinfection performance. Post-treatment also played a crucial role in the reduction of the antibiotic resistance gene sul1 and the indicator genes intl1 (mobile genetic element) and 16S rRNA (total bacterial number), whereas inactivation of antibiotic resistant bacteria was dominated by the ozonation process. In summary, the combined disinfection mechanisms of ozonation (chemical) and filtration (physical) resulted in an effective abatement of a wider range of microbial parameters than the individual processes. Regrowth during post-treatment has only been observed for the parameters intact cell counts and Pseudomonas aeruginosa with mean concentration increases of 0.5–1 log units.

中文翻译：

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城市污水臭氧化和生物后处理对微生物质量参数的影响

臭氧化是一种成熟的废水处理工艺，其消毒程度与剂量有关。其后通常是生物后处理，主要目的是减少氧化副产物。然而，关于臭氧化和生物后处理相结合对微生物质量参数的影响的研究很少。这项长期研究调查了使用六种不同过滤工艺（4 个深床过滤系统和 2 个垂直流人工湿地）作为生物后处理的中试规模臭氧化。广泛的微生物参数已被监测以全面评估消毒性能。虽然营养细菌（大肠杆菌和肠球菌）在很大程度上被臭氧灭活，但孢子形成产气荚膜梭菌和病毒指示体细胞大肠杆菌噬菌体表现出高臭氧耐受性，只能在随后的过滤步骤中有效保留。延长的水力停留时间以及后处理中的精细过滤材料被证明有利于减少粪便指示剂。在深床过滤器中，混凝剂剂量是影响消毒性能的另一个重要因素。后处理在减少抗生素抗性基因sul 1 和指示基因intl方面也起到了至关重要的作用。1（移动遗传元件）和 16S rRNA（细菌总数），而抗生素抗性细菌的灭活主要由臭氧化过程控制。总之，臭氧化（化学）和过滤（物理）的组合消毒机制导致比单个过程更广泛的微生物参数的有效减少。仅在参数完整细胞计数和铜绿假单胞菌的平均浓度增加 0.5–1 log 单位时观察到后处理过程中的再生。