Advancing membrane bioelectrochemical reactor (MBER) with hollow-fiber membranes installed in the cathode compartment

BACKGROUND: Synergistic cooperation between membrane technology and microbial fuel cells (MFCs) creates a membrane bioelectrochemical reactor (MBER) that can produce electricity directly from organics while maintaining a high-quality effluent. This study aims to advance the MBER concept with hollow-fiber membranes installed in a cathode compartment for alleviating membrane fouling. RESULTS: The MBER achieved 90% removal of the chemical oxygen demand (COD), and 69% removal of the total inorganic nitrogen; the turbidity of the membrane permeate was mostly below 2 NTU. The operation of this MBER theoretically consumed 0.09 kWh m^-3, significantly lower than the energy consumption in membrane bioreactors (MBRs). The energy production in the MBER was 0.011-0.039 kWh m^-3 from the synthetic solution, or 0.032-0.064 kWh m^-3 from the cheese wastewater. The Coulombic efficiency varied between 10 and 30%, affected by the substrate type and loading rates. CONCLUSIONS: The MBER with ultrafiltration membranes installed in the cathode greatly improved membrane performance with a constant low trans-membrane pressure (which drives water through the membrane) during the testing period, when treating either a synthetic solution or real wastewater from a cheese plant. The MBER technology has potential advantages in energy consumption/production compared with MBRs, and may offer better handling of operating conditions than AnMBRs.