Sustainable wastewater management through nitrogen-cycling microorganisms

Nitrogen-cycling microorganisms play essential roles in biological wastewater treatment, where nitrogen is removed with substantial energy and chemical consumption and greenhouse gas emissions. The discoveries of new nitrogen-cycling microorganisms paved the way for a remarkable paradigm shift from energy-negative and carbon-positive to energy-positive and carbon-neutral wastewater management. This Review reflects on the trajectory of these microbial discoveries and summarizes the technological progress enabled by them thus far. By bridging the gap between environmental microbiologists and water engineers, who are both interested in these new nitrogen-cycling microorganisms but with different focuses and expertise, this Review acknowledges the challenges encountered and illuminates the exciting future ahead. The continued close collaboration between scientists and engineers will keep redefining the landscape of wastewater management.