Electrochemical membrane bioreactors

Electromembrane bioreactors (eMBRs) integrate electrochemical, biodegradation, and membrane processes into one technology. eMBRs are MBRs integrated with electrochemical processes. The complementary actions of these processes improve the performance of eMBRs, compared to the conventional MBRs, regarding membrane fouling attenuation and retention of solids in the bioreactors. The electrochemical processes in an eMBR complement the biological and filtration processes in MBR by reducing membrane fouling and improving sludge dewaterability. Therefore this technology (eMBR) could ensure better effluent quality compared to individual biological, filtration, or electrochemical processes. eMBRs can also be employed to achieve electrocatalysis and degrade organic contaminants; these types of eMBRs are known as electrocatalytic MBRs (EC-MBRs). Different configurations of eMBRs and EC-MBRs are discussed in this chapter. These configurations include (submerged) aerobic electro-MBR (SEMBR), electroanaerobic MBR, electroosmotic MBR, electro-Fenton MBR, and bioelectrochemical systems coupled with MBR. This chapter deals with the fundamentals, recent advances, strengths, challenges, and opportunities of the different eMBR/EC-MBR systems. Among the different systems, biochemical-based and osmotic-based processes are more attractive, owing to their promising potentials, such as nutrient and solute recovery, electricity generation, production of CH4 and H2, and alleviation of the reverse salt diffusion/salinity accumulation problem in the conventional MBR. Nevertheless, the techno-economic feasibility of this technology needs further investigation because it is not well developed yet for commercial applications compared to the conventional MBR. Practical applications of eMBR/EC-MBR systems should be the focus of future research in terms of their scale-up for large-scale operations, the durability of electrode and membrane materials, and the purity of the final products from these systems.