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

Ammonia nitrogen (NH4+-N) is a key pollutant of concern in micropolluted water. Advanced oxidation processes (AOPs) show an excellent performance in NH4+-N removal. Through a literature review and analysis, the mechanisms and performance of AOPs for NH4+-N removal are comprehensively summarized. The primary active species for NH4+-N degradation in different processes are discussed. The roles of NH4+-N in DBP formation by UV-based treatment are elucidated. The current advances and new insights of NH4+-N treatment from micropolluted water for practical engineering applications are proposed. Nitrogen species generated via NH4+-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 NH4+-N, whereas differences in NH4+-N concentration, complex water backgrounds, water supply pipeline corrosion, regional and seasonal variations, or something should be addressed. It is necessary to deeply investigate NH4+-N treatment and fate when considering the application of AOPs in micropolluted water.