Nutrient removal and recovery from wastewater by microbial fuel cell-based systems

Large amounts of nitrogen are contained in different types of real wastewater, which have great potential for resource recycling. Microbial electrochemical technologies (METs) are a promising approach for capturing various nitrogen forms (inorganic ammonia, nitrate/nitrite, and organic nitrogen) from wastewater while recovering the nitrogen resources. METs-assisted nitrogen recovery technology combines separation units and downstream recovery units (e.g., membrane technology, stripping technology, and struvite precipitation) to enable energy-efficient nitrogen conversion and recovery, demonstrated across urine, digestate, and landfill leachate. Life cycle assessments reveal METs’ environmental benefits over traditional methods, yet electrode/material costs and functional microbiota optimization require attention. However, METs-assisted nitrogen recovery technology still faces challenges in engineering application, system stability, and cost-effectiveness, particularly for real wastewater with complex contaminants. In the future, METs-assisted nitrogen recovery technology should strive to expand its application to more fields of high-nitrogen wastewater treatment, especially for the wastewater rich in high nitrate nitrogen and organic nitrogen forms. With the systematic optimization and construction of the system and the elaborate design of functional microbial consortia, it is possible to further reduce the operating costs while enhancing the efficiency of nitrogen recovery. Bridging lab-scale innovations to engineering applications will unlock METs’ potential in sustainable wastewater management and circular resource economies.