Analysis of Microbial Diversity of Domestic Wastewater at Different Treatment Stages of the A/O Process

KONG Deqi; XU Qian; DING Qiuju; TAN Ruyi; XIAO Shuangyin; HE Yi; CAO Zirui; WEI Jiaxin; SHAO Huanhuan

doi:10.15926/j.cnki.issn1672-6871.2025.01.012

Abstract：Revealing the diversity of wastewater microbial communities within the A/O process system can provide data support for the regulation of the process,which is conducive to the improvement of wastewater treatment efficacy.In this study,the macro-genome sequencing of the wastewater from anoxic tank,aerobic tank and sedimentation tank was performed in a domestic wastewater treatment unit of A/O process in Shuangliu District,Chengdu City,for example,and microorganisms of 213 phyla and 4 477 genera were identified.Through the analysis of the composition of the wastewater flora,it was found that the microbial community composition of the anoxic and aerobic tank wastewater was relatively similar in structure,while there was a significant difference with the sedimentation tank wastewater,and the dominant phylum of the three water samples was Pseudomonadota,with the relative abundance of 46.73%,46.50%,and 46.91%,respectively,followed by Bacteroidota,with the relative abundance of 18.11%,18.03%and 12.45%,and at the genus level,the main dominant genera in both anoxic and aerobic tank wastewater were Nitrospira and Ferruginibacter,while Dechloromonas and Azonexus became the main dominant genera in sedimentation tank wastewater.Functional genes analysis revealed that 23 genes involved in the nitrogen cycling pathway were mainly narG,nirKS and hao,and most of these genes had significantly higher abundance in anoxic and aerobic tank wastewater than in sedimentation tank.The main genera associated with carbohydrate-activating enzymes in the wastewater were Nitrospira,Ferruginibacter,Dechloromonas,Pirellula,Nitrosomonas and Azonexus,which were also the main denitrifying genera,and the enhancement of these genera may help to synchronize the improvement of carbon and nitrogen metabolism of the A/O process.In addition,Pseudomonadota,Actinomycetota,Bacteroidota,Nitrospirota,and Myxococcota are closely related to antibiotic resistance genes,and future research on enhancing the removal of antibiotic resistance genes in the A/O process can be more focused on these groups of microorganisms.The research on improving the antibiotic resistance gene removal ability of A/O process in the future can be started from these microorganisms.