pH值对短程反硝化及N2O释放特性影响

Effect of pH values on shortcut denitrification and nitrous oxide emission

以普通活性污泥为种泥,控制COD/N为2,通过逐步提升NO2^-—N浓度(由15上升至200 mg/L)的方式在小试SBR反应器中实现了短程反硝化的启动;稳定运行期间,NO2^-—N的平均去除率达99.5%.在此基础上,通过批式试验考察了不同进水pH值(7.1、8.2和9.3)对短程反硝化及N2O释放特性的影响.结果表明,随着进水pH值的升高,平均反硝化速率由0.087 9上升至0.094 1和0.107 2 mg/(min·gSS);反硝化效率先降后升,分别为98.70、96.52和99.10%;而N2O的释放量随pH值升高呈降低的趋势,pH值为7.1时的释放量分别是8.2和9.3时的2.82和8.04倍.因此,适当提升进水pH值可大幅降低短程反硝化过程N2O的释放量.

Shortcut denitrification was successfully started up in a sequencing batch reactor(SBR)by evaluating nitrite nitrogen concentration from 15 to 200 mg/L.Batch experiments were conducted to investigate the effect of pH values(7.1,8.2 and 9.3)on the denitrification rate and nitrous oxide(N 2 O)emission.The results show that the nitrite removal rate increased from 0.087 9 to 0.094 1 and 0.107 2 mg/(min·gSS),and then decreased with the increase of pH.While the removal efficiency of nitrite firstly decrease from 98.70 to 96.52 and then increased to 99.10%.The amount of N2O emission decreased with the increase of pH values,and the N2O emission amount at pH 7.1 was 7.04 times more than that at pH 9.3.The results demonstrated that the N2O emission can be decreased significantly by increasing the influent pH value during shortcut denitrification.