硝化过程亚硝态氮氧化阶段的N_2O产生情况

Production of Nitrous Oxide from Nitrite Nitrogen Oxidation during Nitrification of Domestic Sewage

为考察生活污水硝化过程的亚硝态氮氧化阶段是否有N2O产生,利用经生活污水长期驯化后的污泥和SBR反应器,在pH值为8、曝气量为60L/h的条件下,研究了不同NO2-N浓度下N2O的产生情况。试验发现,除了氨氧化阶段,NO2-N氧化阶段也是N2O的重要产生源。调节NO2-N浓度分别为81.45、65.29、40.18和16.82mg/L,结果发现随着NO2-N浓度的降低,N2O的产生量和转化率也有所降低,但当NO2-N浓度降低至1.64mg/L时,N2O的产生量和转化率却有所升高。此外,还考察了NO2-N浓度为30mg/L左右时,不同pH下N2O的产生情况。结果表明,随着pH的升高则N2O的产量逐渐减少。综合考虑运行成本和减少N2O生成量的效果,应控制pH值在7以上。

Long-term acclimated sludge and SBR were used to investigate the production of nitrous oxide （ N2 O） from nitrite nitrogen oxidation during nitrification of domestic sewage under the conditions of pH8, aeration rate 60 L/h and different nitrite nitrogen concentrations. Besides ammonium oxidation, nitrite nitrogen oxidation process is an important source of N2O. When nitrite nitrogen concentrations are regulated at 81.45 mg/L, 65.29 mg/L, 40.18 mg/L and 16.82 mg/L respectively, the production and conversion rate of N20 are gradually reduced. However, when nitrite nitrogen concentration is decreased to 1.64 mg/L, the production and conversion rate of N2O are increased. With the increase of pH, the production of N2O is gradually reduced when nitrite nitrogen concentration is 30 mg/L. Taking the operation cost and reduction of N2O emission into account, pH should be controlled at more than 7.