Influence of operational modes and aeration rates on N₂O emission from urban sewage treatment using a pilot-scale sequencing batch reactor.

摘要

Pilot-scale experiments were carried out in a sequencing batch reactor to study the effect of operational modes/conditions of aeration on the emission of N₂O during sewage treatment. The results showed that the flow-based emission factor of N₂O under the aeration mode of 60-min anoxic/60-min aeration decreased from 0.75 to 0.42 g (ton of wastewater)-1 with the aeration rate increasing from 0.6 to 1.2 m3 h-1. This emission factor was lower than that under the aeration mode of 30-min anoxic/90-min aeration, which was 0.61-1.57 g (ton of wastewater)-1 within the same studied range of aeration rate. When the aeration rate was lowered to 0.3 m3 h-1, a smallest emission rate of N₂O of 0.16-0.28 g (ton of wastewater)-1 was observed because of decreased removal efficiencies of NH₄+-N (54.3%-57.8%) with insufficient O₂ supply.