Recent Advances on Ammonia Removal in Micropolluted Water Treatment by Advanced Oxidation Processes: Performance, DBP Formation, and Engineering Application

Ammonia nitrogen (NH 4 + -N) is a key pollutant of concern in micropolluted water. Advanced oxidation processes (AOPs) show an excellent performance in NH 4 + -N removal. Through a literature review and analysis, the mechanisms and performance of AOPs for NH 4 + -N removal are comprehensively summarized. The primary active species for NH 4 + -N degradation in different processes are discussed. The roles of NH 4 + -N in DBP formation by UV-based treatment are elucidated. The current advances and new insights of NH 4 + -N treatment from micropolluted water for practical engineering applications are proposed. Nitrogen species generated via NH 4 + -N-mediated promote the nitrogen-DBP formation during the water disinfection process. In practical applications, UV-based combined processes show promising potential for the removal of DBP precursors NH 4 + -N, whereas differences in NH 4 + -N concentration, complex water backgrounds, water supply pipeline corrosion, regional and seasonal variations, or something should be addressed. It is necessary to deeply investigate NH 4 + -N treatment and fate when considering the application of AOPs in micropolluted water.