A/O工艺N_2O的产生与释放的影响因素

采用A/O工艺,在连续运行条件下,以DO、SRT和硝化液回流比(R)为影响因素,对A/O生物脱氮工艺处理模拟城市生活污水过程中N2O的释放进行了研究。实验结果表明,SRT对A/O工艺N2O释放的影响最大,其次是DO,R的影响最小。N2O转化率随着SRT的升高而降低,当SRT从10 d升高到20 d时,总N2O平均转化率从0.319%下降到0.002%。总N2O转化率随着好氧池DO的升高先降低后有所升高,当DO分别为0.6 mg O2/L、1.2 mg O2/L、2.5 mg O2/L时,反应器的总N2O平均转化率分别为0.306%、0.007%和0.013%。R对N2O释放的影响差异不明显,总N2O平均转化率在300%时最低,为0.007%。N2O释放量最低的工艺运行条件组合是SRT为20 d、DO为1.2 mg O2/L、R为300%。

Influencing factors of nitrous oxide production and emission in A/O process

An A/O reactor was used under a continuous operation condition to study the influence of DO, SRT and nitrification reflux ratio (R) on N₂O emission during artificial sewage treatment. The orthogonal experiment results showed that, SRT owed the greatest influence on N₂O emission in A/O process, followed by DO, and R had a minimum effect. The total N₂O conversion rate in A/O reactor decreased when there was a longer SRT, from 0.319% to 0.002% on average when SRT increased from 10 d to 20 d. As to DO, the average total N₂O conversion rate decreased from 0.306% to 0.007% firstly, and then it increased slightly to 0.013% when DO increased from 0.6 mg O₂/L to 2.5 mg O₂/L, via 1.2 mg O₂/L. No apparent relationship was found between N₂O emission and R, whereas a lowest average total N₂O conversion was found at R of 300%. The optimal combination of the operational conditions was DO for 1.2 mg O₂/L, SRT for 20 d and R for 300%.