Treatment of real municipal wastewater in a sponge anaerobic baffled reactor with cultivation-based microbial...

Conventional anaerobic baffled reactors often demonstrate inadequate performance in municipal wastewater treatment, necessitating innovations for improved efficiency. This study investigated sponge anaerobic baffled reactor (SABR) for municipal wastewater treatment and identified dominant bacterial strains using 16S rRNA sequencing. SABR, consisting of six compartments each provided with low-cost, porous polyurethane sponge sheet, facilitated biomass immobilization and microbial proliferation to enhance reactor treatment performance. The reactor underwent prolonged mesophilic operation for approximately four months, during which hydraulic retention times (HRTs) were sequentially adjusted between 18 and 6 h. The reactor performed most effectively under 8 h HRT, achieving removal efficiencies of 79% for chemical oxygen demand (COD), 96% for total suspended solids (TSS), 60% for total nitrogen (TN), and 53% for total phosphorus. At this operating conditions, the effluent quality satisfied the permissible discharge limits for COD, TSS, and TN. Microbial characterization identified eight dominant bacterial strains, including one potentially novel strain requiring further taxonomic validation. This study presents SABR as a promising bioreactor for decentralized wastewater treatment; however, further long-term and field-scale studies are needed to confirm its robustness and scalability. Additionally, it opens avenues for further research into the roles of diverse microbial consortia in optimizing anaerobic wastewater treatment processes.