Abstract:
Anaerobic Membrane Bioreactors (AnMBRs) combine the advantages of anaerobic processes and MBR technology to increase effluent quality and recover energy. However, these systems are associated with several operational challenges such as membrane fouling and loss of dissolved methane which increase operation and energy expenses. In this study, a new system configuration was developed that combines an anaerobic fluidized membrane bioreactor (AnFMBR) with a Microbial Electrolysis Cell (MEC) and tested for the treatment of synthetic wastewater. The effects of electrochemical reactions in the AnFMBR-MEC were examined in terms of Chemical Oxygen Demand (COD) removal, biogas generation, fouling potential, and microbial community characteristics. The startup of the AnFMBR-MEC system was 25 days faster than the AnFMBR alone. While both reactors exhibited a high COD removal (~90%), the new AnFMBR-MEC system enhanced the average methane yield by 56%. In addition, the new system reduced membrane fouling with a maximum transmembrane pressure value nearly 6.5 folds lower than that exhibited by the AnFMBR. Similar bacterial community existed in both reactors but with different abundance and localization. In the AnFMBR-MEC, Direct Interspecies Electron Transfer was possibly the dominant route for acetate consumption due to the abundance of Geobacter and Methanosarcina on granular activated carbon and in suspension. Taken together, the new AnFMBR-MEC system provides a promising technology for recovery of resources (reclaimed water for non-potable reuse and energy) from wastewater.
