Microbial electrochemical technologies assisted nitrogen recovery from different wastewater sources: Performance, life cycle assessment, and challenges

A large amount of chemical energy in wastewater is highly valuable in resource utilization, and nitrogen is one of the key nutrients and contaminants in diverse wastewater. Traditional wastewater treatment technologies focus on removing nitrogen from wastewater, which s not sustainable and consumes a lot of resources and energy. Microbial electrochemical technologies (METs)have been invested to transform conventional energy-intensive wastewater treatment into a resource recovery process for reclaiming valuable nitrogen products. Nevertheless, the engineering application of METs from different real wastewater is still in its infancy due to the complex characteristics of different waste streams. This review broadly concludes the present METs-assisted nitrogen recovery systems and the ammonium recovery performance of different wastewater streams. Additionally, the environmental impact and economic analysis of different METs and end products are presented to demonstrate their application potential. The results show that the microbial electrolysis cell (MEC)has better engineering application compared to microbial fuel cell (MFC), which could reduce the overall environmental burden and infrastructure costs. And coupling the MEC with stripping technology can be a preferable option for ammonia recovery.. Finally, present challenges and prospects in the field of METs-assisted nitrogen recovery are discussed, including scaling up bioreactors, enhancing strategies, and conducting life cycle assessment of the entire recovery process.