Deterministic Mechanisms Dominate Bacterial Communities Assembly and Functionality in Industrial Wastewater Treatment System

Microbial communities are responsible for biological treatment of many industrial wastewater, but our knowledge of their diversity, assembly patterns and function is still poor. Here, we analyzed the bacterial communities of wastewater and activated sludge samples taken from 11 full-scale industrial wastewater treatment plants (IWWTPs) characterized by the same process design but different wastewater types and WWTP compartments. We found significantly different diversity and compositions of bacterial assemblages among distinct wastewater types and IWWTPs compartments. IWWTPs bacterial communities exhibited a clear species abundance distribution. The dispersal-driven process was weak in shaping IWWTP communities. Meanwhile, environmental and operating conditions were important factors in regulating the structure of the activated sludge community and pollutants removal, indicating that bacterial community was largely driven by deterministic mechanisms. The core microbial community in IWWTPs was different from that in municipal wastewater treatment plants (MWWTPs), and many taxa (i.e. the genus Citreitalea ) rarely were detected before, indicating IWWTPs harbor unique a core bacterial community. Furthermore, we found that bacterial community composition was strongly linked to activated sludge function. Overall, our study enhances the mechanistic understanding of the IWWTP microbial community diversity, assembly patterns and function, which provides important implications for microbial ecology and wastewater treatment processes.