Combining electrochemical nitrate reduction and anammox for treatment of nitrate-rich wastewater: A short review

Treatment of nitrate-rich wastewater is important but challenging for the conventional biological denitrification process. Here, we propose combining the electrochemical reduction and anaerobic ammonium oxidation (anammox) processes together for treatment of nitrate-rich wastewater. This article reviews the mechanism and current research status of electrochemical reduction of nitrate to ammonium as well as the mechanism and applicability of the anammox process. This article discusses the principles, superiorities and challenges of this combined process. The feasibility of the combined process depends on the efficiency of electrochemical nitrate reduction to ammonium and the conditions in the anammox process to use the reduced ammonium as the substrate to achieve deep nitrogen removal. The article provides a feasible strategy for using the electrochemical reduction and anammox combined process to treat nitrate-rich wastewater. [Display omitted] •High nitrate wastewater was treated by electrochemical reduction-anammox process.•Strategies to improve electrochemical performance focus on electrode materials.•The electric chemoselectivity of NH4+ is the key to construct the combined process.•Both viable electrochemical reduction-anammox processes are proposed.•Challenges and superiorities of electrochemical reduction-anammox process are given.