Recent advances in anodic anaerobic ammonia oxidation in microbial electrolysis cells

Electricity-driven anaerobic ammonia oxidation (anammox) has garnered extensive attention as a novel, up-and-coming ammonium removal technology because of its broad, cost-efficient, and eco-friendly application. However, the anammox occurring in anode did not receive the attention it deserved. The underlying mechanisms, regulatory strategies, and technical and economic potential of anodic anammox technology are still poorly understood. Thus, we discussed the recent advance in anodic anammox, emphasizing the associated bacteria groups, and assessed the technological and economic potential of the process in terms of operating conditions and energy consumption. It was unravelled that the energy consumption of anodic anammox varies from 0.002 to 0.80 ± 0.09 kWh kg⁻¹ N. This review can improve our understanding of anodic anammox and provide a theoretical foundation for future regulation and practical applications.