Capturing wastewater nitrogen through METs-assisted dissimilatory nitrate reduction to ammonium (DNRA) using various electron donors: Recent Trends, challenges, and future directions

[Display omitted] •Reaction mechanism of DNRA pathway within vary electron donors were summarized.•Nitrate selectively transformation between denitrification and DNRA was discussed.•Characteristic of key DNRA bacteria in various environments were comprehensively summarized.•MET-assisted DNRA presents a sustainable approach for recycling nitrate-containing wastewater.•Opportunities and challenges were proposed for advancing MET-assisted DNRA development. The rapid increase in population, urbanization, and industrialization have led to the discharge of wastewater with high-concentration of nitrate contaminant. Here we emphasize the intervention point of nitrate fate, dissimilatory nitrate reduction to ammonium (DNRA), and propose a potential strategy to achieve nitrogen recovery. The resource recovery process of applying microbial electrochemical technologies (METs) to traditional energy-intensive wastewater treatment to recover valuable nitrogen products was investigated. This review systematically elucidates the DNRA pathway, focusing on recent trends of METs-assisted DNRA-driven nitrogen recycling and the use of different electron donors in current research. Different types of DNRA functional microorganisms were critically summarized and compared, laying the foundations for applying DNRA keystone species. In addition, the competition and switching mechanism between denitrification process and DNRA process are analyzed in detail, which provides support for DNRA-driven nitrogen recovery by microbial electrochemical technology. Finally, the present challenges and prospects in METs-assisted DNRA for nitrogen recovery are discussed, including enhancement strategies, possible integration with other processes, and the potential application of multi-component substrates.