N₂O emission and control in wastewater treatment of biological nitrogen removal

Aiming at the increasing concentration of N₂O in the atmosphere year by year, nitrification and denitrification in biological nitrogen removal process are considered as the major sources for N₂O production in wastewater treatment. The emission mechanics, affecting factors such as temperature, pH, dissolved oxygen concentration (DO), SRT and carbon to nitrogen ratio (C/N) of wastewater are discussed in this paper. Finally, the preliminary strategies for N₂O emission control from wastewater treatment of biological nitrogen removal are put forward based on microorganism population optimization and process operation which affect the N₂O production: the maintenance of relative long SRT, high DO concentration during aeration, strict anoxic condition in denitrifying and neutral or alkaline condition.