N_2O Production during Nitrogen Removal via Nitrite from Domestic Wastewater: Main Sources and Control Method

摘要

Nitrite has been commonly recognized as an important factor causing N_2O production, which weakened the advantages of nitrogen removal via nitrite. To reduce and control N_2O production from wastewater treatment plants, both long-term and batch tests were carried out to investigate main sources and pathways of N_2O production during nitrogen removal via nitrite from real domestic wastewater. The obtained results showed that N_2O production during nitrogen removal via nitrite was 1.5 times as much as that during nitrogen removal via nitrate. It was further demonstrated that ammonia oxidization were main source of N_2O production during nitrogen removal from domestic wastewater; whereas, almost no N_2O was produced during nitrite oxidization and anoxic denitrification. N_2O production during nitrogen removal via nitrite decreased about 50% by applying the step-feed SBR, due to the effective control of nitrite and ammonia, the precursors of N_2O production. Therefore, the step-feed system is recommended as an effective method to reduce N_2O production during nitrogen removal via nitrite from domestic wastewater.