Electrochemically Assisted Anaerobic Digestion Processes: From Enhancement Biogas Production to Recovery of Added-Value Compounds

Traditional anaerobic digestion (AD) is a well-established technology that converts organic matter into biogas. However, its performance is highly sensitive to substrate composition, which can lead to low methane production and high sensitivity to toxic compounds. To overcome these limitations, the integration of AD with electrochemical systems has been proposed in recent years, an approach that has increased process efficiency and stability. This makes AD a much more robust system, allowing for the treatment of a wider variety of waste. Currently, the most relevant electrochemical systems coupled with AD are microbial electrolysis cells (MECs), microbial fuel cells (MFCs), and electrodialysis (ED) systems. MEC enhances biogas or hydrogen production and improves methane quality while also reducing organic discard in the effluent. MFCs, when integrated with AD, offer a way to directly generate electricity from organic waste. Recently, ED has been coupled with AD to recover valuable compounds like volatile fatty acids from fermentation, which not only increases treatment efficiency but also obtains industrially valuable products. This review summarizes recent research on the design and configurations of AD combined with these electrochemical systems.