Effect of the addition of organic carbon sources on nitrous oxide emission in anaerobic-aerobic (low dissolved oxygen) sequencing batch reactors

Abstract

The effect of additional organic carbon sources on the production of nitrous oxide (N 2 O) in anaerobicaerobic (low dissolved oxygen) real wastewater treatment system was investigated. In this paper, three laboratoryscale sequencing batch reactors (SBRs) (SBR-1, SBR-2 and SBR-3) were operating under an anaerobic-aerobic (low dissolved oxygen, 0.15-0.45 mg$L -1 ) configuration. The SBRs were 'long-term cultured' respectively with a single municipal wastewater sample, sodium acetate, and a waste-activated sludge alkaline fermentation liquid as the additional carbon sources of real wastewater. Off-gas analysis showed that N 2 O was emitted into the atmosphere during the aerobic (low dissolved oxygen) period in the three SBRs, and the order of N 2 O emission rate was SBR-2 > SBR-1 > SBR-3. It was observed that the higher poly-β-hydroxyvalerate fraction of polyhydroxyalkanoates, the lower glycogen transformation and less nitrite accumulation was in SBR-3, while the opposite behavior was observed in SBR-2. Further research indicated that the interaction of the factors above potentially affected the N 2 O emission in the anaerobic-aerobic (low dissolved oxygen) system.

Nitrous oxide generation in denitrifying phosphorus removal process: main causes and control measures

“…Moreover, N 2 O can contribute to the destruction of ozone layer through reacting with oxygen (O 2 ) to produce nitric oxide (NO) in the stratosphere (Ravishankara et al 2009). It has long been known that biological wastewater treatment is an important source of N 2 O emissions (Kampschreur et al 2009;Li et al 2010;Wunderlin et al 2012). Therefore, it is urgent to identify the causes of N 2 O emission and reduce this phenomenon from biological wastewater treatment process.…”