[Meta-analysis of Microbial Communities in the Activated Sludge of Wastewater Treatment Plants Under Different...

Microbial communities in wastewater treatment plants(WWTPs) are very important for water purification in the context of public drinking water safety and environmental health. Therefore, it is necessary to explore the trends in microbial community structure and diversity in sewage treatment plants and their main environmental impact factors under different climates in China. Based on high-throughput sequencing techniques, a meta-analysis was conducted to screen the 16S rRNA genes in an open database. We analyzed the trends in microbial community structure and diversity in WWTPs under three climate types(Dwa, Cfa, and Cwa) in China. We then constructed cohesion models to examine the core microbial taxa and their interactions within the communities. We also used a piecewise structural equation model(PSEM) to examine the effects of different climate types on microbial community structure. The three climate types significantly affected the structure and diversity of the microbial communities, with patterns correlated with influent pH, mixed liquid temperature, conductivity, and nitrogen concentrations(P<0.05). Based on the PSEM analysis, the β-diversity of the microbial communities was directly correlated with latitude, while α-diversity was indirectly correlated with latitude through conductivity and water temperature. Based on the cohesion modeling, microbial community stability was the highest under Dwa climate followed by the Cfa climate. This could be explained by a small subset of highly connected taxa capable of withstanding disturbance, indicating an important stability role. In contrast, the stability of the microbial communities under the Cwa climate was low, and no species with strong negative cohesion were observed. Overall, the structure, diversity, and stability of microbial community in WWTPs were found to be sensitive to climate, and the responsive mechanisms of α-diversity and β-diversity with respect to latitude were distinct.