The roles of typical emerging pollutants on N₂O emissions during biological nitrogen removal from wastewater

N₂O as a potent greenhouse gas often generates in the biological nitrogen removal (BNR) processes during wastewater treatment, which makes BNR become an important greenhouse gas emission source. The emerging pollutants (EPs) are ubiquitous in wastewater and they have shown to influence the BNR processes. However, the deep discussion on potential impacts of EPs on N₂O emissions during BNR is rare. Moreover, the experimental parameters for EPs investigation in most of literatures are generally not in line with real-world BNR processes, which calls for deep elucidating the roles of EPs on N₂O production and emission. In this work, a critical review summarizes the existing literature about influences of typical EPs on N₂O emissions and associated mechanisms during BNR, and it discusses the impacts of some easily overlooked factors, such as real EPs environmental concentrations, EPs bioaccumulation, and multiple EPs coexistence on N₂O emissions. This review will provide an insight into exploring and mitigating threats posed by typical EPs on N₂O emissions.