Microbial community changes in a full-scale wastewater treatment system with a rotating biological contactor integrated into anaerobic-anoxic-oxicoxic processes

The objective of this study was to investigate the changes of microbial communities in different treatment units of a full-scale wastewater treatment plant (WWTP) equipped with a serially combined rotating biological contactor (RBC) and anaerobic-anoxic-oxic-oxic (A²/O²) processes. Highthroughput sequencing results showed that functional communities including Methylotenera, Nitrospiraceae, Terrimonas, Zoogloea, Lysobacter, and Rhodobacter were the most dominant communities in the treatment system. The sequencing results demonstrated that the microbial communities along the different treatment units showed distinct community profiles. Additionally, dominant functional communities with Methylotenera and Methanolobus were significantly enriched on RBC films compared to those in the activated sludge of the RBC treatment unit, indicating that the RBC plays essential functions in the WWTP. In general, thoroughly screening the microbial communities in WWTP equipped with RBC and A²/O² and monitoring the changes over seasons contributed to maintain and adjust the wastewater treatment system in case of decayed treatment efficiencies. Besides, our work could guide us to rapidly set up a new similar WWTP.