O₃-BAC深度处理工艺中细菌群落时空分布及动态变化规律

In order to gain insight into the spatiotemporal distribution and dynamic variation of bacterial communities in the O₃-BAC advanced treatment process of drinking water, bacterial communities, which were in effluents of major process units, filter sand and granular activated carbon (GAC) biofilms in an O₃-BAC advanced treatment process plant in the south of China in summer and winter, were investigated using NovaSeq6000 high throughput sequencing technology. The results showed that pH, turbidity, COD_Mn and total plate count in finished water all met the standards for drinking water quality (GB5749-2006). The bacterial diversity in summer was significantly higher than that in winter, while the bacterial diversity in GAC biofilms was higher than that in filter sand biofilms. In addition, the coagulation sedimentation, ozonization and disinfection process units had a significant effect on the diversity of bacterial community. Furthermore, Proteobacteria was predominant in both water and biofilm samples, and the composition of main phyla was roughly the same, but the spatiotemporal variation was observed in the relative abundance of bacterial community at the phylum level and more obvious at the genus level. Additionally, a number of potential pathogens were detected, including Bacillus, Acinetobacter, Pseudomonas and Mycobacterium, and the OTUs number of them in the core microbiome was not affected by seasonal variation. Moreover, water temperature and BDOC were the major water characteristics that influenced bacterial community distribution. In a word, the above results provided evidence of spatiotemporal variation of bacterial communities in the O₃-BAC advanced treatment process, and contributed to microbiological safety assurance of drinking water.