Study on the Mechanism of N2O Emission from Biological Nitrogen Removal Process: The Use of Inhibitors

Batch Experiments with the combination use of inhibitors were conducted to identify the mechanism of N₂O emission from anoxic-aerobic sequencing batch reactors (SBR) acclimated under different oxygenation levels. Oxygenation has an important effect on the N₂O emission and most of the N₂O was produced during the aerobic phase, in spite of the oxygenation level. During the anoxic phase, nitrate ammonification was the major producer of N₂O while denitrification performed as a sink of N₂O. During the aerobic phase, both nitrifier denitrification and coupled nitrification-denitrification were responsible for N₂O emission in SBR with low and high oxygenation, while nitrifier denitrification was the major source of N₂O emission in SBR with mid oxygenation.