Use of polymeric scouring agent as fluidized media in anaerobic fluidized bed membrane bioreactor for wastewater treatment: System performance and microbial community

New attempts using polymeric media with a tubular shape consisting of polyvinylidene fluoride (PVDF) were made as fluidized agent for anaerobic fluidized bed membrane bioreactor (AFMBR) in wastewater treatment. The AFMBR added with PVDF media was operated at room temperature and hydraulic retention time (HRT) from 4 to 16 h to investigate membrane fouling, organic removal efficiency, and microbial structure. Results showed that the PVDF media reduced membrane fouling effectively due to their scouring actions to clean the membrane. Transmembrane pressure (TMP) was maintained less than 0.1 bar during the operational period. More than 90% of chemical oxygen demand (COD) removal was achieved, yielding 10 mg/L of COD in membrane permeate. The energy required to operate the AFMBR using PVDF media was only 1.09 × 10⁻² kWh/m³. The electrical energy produced by AFMBR was 0.246 kWh/m³, which is much higher than that required for system operation. Microbial community analysis based on 16S rRNA gene sequencing showed that the microbial community on PVDF biofilm was distinct from that in the suspended microbes. Importantly, it was found that dominant propionate-catabolizing bacteria on PVDF media include Desulfobulbus and syntroph Syntrophobacter while the key methanogenic player shifted from hydrogenotrophic Methanolinea to acetoclastic Methanothrix during the operation.