Large pilot-scale submerged anaerobic membrane bioreactor for the treatment of municipal wastewater and biogas production at 25 ° C

The aim of this work was to demonstrate the operation of a large pilot-scale submerged anaerobic membrane bioreactor (5.0 m(3)) for biogas production from municipal wastewater at ambient temperature of 25 degrees C. To the best of our knowledge, this is the largest one-stage submerged AnMBR that has ever been reported. This AnMBR realized a hydraulic retention time (HRT) of 6 h and a treatment capacity of 20 m(3) d(-1), obtaining excellent effluent quality with COD removal efficiency over 90% and BOD5 removal over 95%. The biogas yield of the AnMBR was 0.25-0.27 L g(-1) removed COD and 0.09-0.10 L L-1 raw wastewater. The methane content of the biogas was at the range of 75%-81%. The COD and nitrogen mass balance were also identified based on longterm operation. The hollow-fiber membrane module realized a flux of 2.75-17.83 LMH. An online backwash chemical cleaning system helped to lower the transmembrane pressure timely.

Automated summary

This study demonstrated the operation of a large pilot-scale submerged anaerobic membrane bioreactor for biogas production from municipal wastewater, achieving excellent effluent quality with high COD and BOD5 removal efficiencies. The biogas yield and methane content were also determined, and the long-term operation provided insights into COD and nitrogen mass balances. The membrane module showed a high flux and an online backwash chemical cleaning system helped maintain membrane performance.