The role of microbial electrolysis cell in urban wastewater treatment: integration options, challenges, and prospects

Microbial electrolysis cell (MEC) is an anaerobic biological process for the conversion of organics in wastewater into renewable energy in the form of hydrogen or methane. However, MEC cannot be used as a standalone technology for urban wastewater treatment, and post-treatment or integrated processes are required to meet water reuse and discharge limits. Recent advances in material science and the discovery of new microorganisms capable of extracellular electron transfer to the electrodes have widened the integration opportunities of MEC in mainstream and side-stream urban wastewater treatment. This review addresses recent developments in the integration of MEC with other processes such as membrane filtration, anaerobic ammonium oxidation and anaerobic digestion, as well as discusses current challenges and new integration opportunities.