S/N质量比对硫化物自养反硝化过程N_2O还原与积累的影响

Effect of S/N ratio on N_2O reduction and accumulation during sulfide-driven autotrophic denitrification

利用成熟硫化物自养反硝化活性污泥,采用微电极系统探讨初始S/N比率对N_2O还原与积累释放的影响。研究结果表明,在硫化物自养脱氮过程中,提高初始S/N有效缓解了不同氮还原酶之间的电子竞争,不仅明显提高了N_2O与NO_3^-的降解速度,而且能避免了NO_2^-、FNA以及N_2O的积累。其中,N_2O的积累量与FNA的积累量正相关且变化倍数接近,表明FNA的存在可能会明显抑制N_2O还原酶活性;而硫化物在一定范围内提高浓度,不仅不会对硫化物自养反硝化脱氮过程产生抑制,反而会促进自养反硝化过程的进行,降低N_2O的积累释放。

The effect of initial S/N mass ratio on the N_2O reduction and accumulation by sulfide-driven autotrophic denitrification sludge was studied using microsensor system.Results showed that the high S/N mass ratio effectively relieved the electron competition among nitrate,nitrite and N_2O reductases.High sulfide stimulated N_2O and nitrate reduction,subsequently reducing nitrite,FNA and N_2O accumulation.The accumulation of N_2O was strongly correlated with the accumulation of FNA,indicating that FNA can bind to the active sites of N_2O reductase and cause competitive inhibition of N_2O reduction.In this study,we confirmed that sulfide stimulated（rather than inhibited） N_2O reduction during sulfide-driven autotrophic denitrification.