亚硝酸盐对外碳源反硝化过程N2O还原的影响

本试验通过批次试验考察了亚硝酸盐对外碳源反硝化过程N2O还原的影响.结果表明NO2--N初始浓度为5.92~35.23mg/L时,随着NO2--N浓度的增加,反硝化过程中N2O的积累量逐渐增加;当NO2--N浓度为35.23mg/L时,NO2--N还原量的46.26%被转化为N2O.通过对比试验得出,N2O还原酶与亚硝酸盐还原酶对电子的竞争和游离亚硝酸(FNA)对N2O还原酶的抑制会导致N2O比还原速率下降,造成反硝化过程N2O积累.基于上述试验结果提出,污水处理厂可通过调控运行条件控制NO2--N浓度,降低反硝化过程的N2O的产生与释放;也可以通过短程硝化提高NO2--N浓度,促进反硝化过程N2O的积累,再通过N2O氧化甲烷减少N2O排放,同时提高产能37%.

The effect of nitrite on N2O reduction during denitrification process using external carbon source

In this study, the effect of nitrite on N2O reduction during denitrification using external carbon sources was investigated in batch tests. The results showed that N2O accumulation grew with increase of the initial nitrite concentration at levels of 5.92~35.23mg/L. Specially, when NO2--N was 35.23mg/L, the N2O produced accounted for 46.26% of the total reduced nitrite. By contrast, the N2O accumulation during denitrification was attributed to the decrease of specific reduction rate due to the synergistic reactionof the free nitrous acid (FNA) inhibition and the electron competition between N2O reductase and nitrite reductase. These findings suggest that the N2O emission control could be achieved by decreasing nitrite concentration through the operation optimization. Moreover, N2O could be used to oxidize methane for increasing energy production by 37% and reducing N2O emission, which could be achieved by increasing nitrite concentration via nitritation.