A mathematical model was developed for identification of the most important mechanism leading to nitrous oxide (N2O) accumulation in denitrifying activated sludge systems. The activated sludge model No. 2d (ASM2d) was extended to include intermediate three steps of the denitrification process. The formation and accumulation of nitric oxide (NO) was assumed to be very low in the performed laboratory experiments. These experiments focused on the combined effects of different electron acceptors (nitrite, nitrate) and with different types of external carbon sources (acetate, ethanol) on the behaviors of polyphosphate accumulating organisms (PAOs) and “ordinary” heterotrophs. The accumulation of N2O was noticeable when the ratio COD/N ratio was low resulting in the limitation of N2O reductase activity. Nevertheless, during the test with ethanol and nitrate no accumulation of N2O was observed. Modeling results confirmed that high nitrite (NO2) concentrations caused inhibition of the nitrous oxide reductase (N2OR) activity leading to high accumulation of N2O. The proposed expanded model ASM2d accurately described the experiments and it could be used to estimate N2O emission during the denitrification process.
Authors
Additional information
- Category
- Aktywność konferencyjna
- Type
- publikacja w wydawnictwie zbiorowym recenzowanym (także w materiałach konferencyjnych)
- Language
- angielski
- Publication year
- 2015
