不同NH_4^+浓度下SBR系统N_2O排放研究

Study on nitrous emission from a SBR wastewater treatment system under different NH_4^+ concentration

研究了不同NH4+浓度下SBR系统脱氮中的N2O排放,并采用PCR-DGGE技术分析了微生物群落特征。结果发现,随着NH4+浓度的提高,氮素转化效率下降,此时脱氮中N2O-N所占比例明显增加,实验条件下N2O-N在脱氮中所占比例在0.25%~6.35%之间;当氮素转化顺利进行时,N2O的排放时期主要在SBR工艺好氧硝化段的同时硝化反硝化阶段,当氮素转化受到抑制时,在好氧硝化段和缺氧反硝化段均有大量N2O排放;不同NH4+浓度下微生物群落会发生相应变化。表明污水脱氮中的N2O排放不仅受氮素转化的影响,同时还受微生物群落结构的影响。

N2O emissions in SBR denitrification process have been studied under different NH4~ concentrations, and PCR-DGGE has been used for analyzing the characteristics of microbial communities. The results show that with the increase of NH4＋ concentrations,the efficiency of nitrogen transformation rate decreases in this SBR system. Meantime,the N2O-N proportion in denitrification increases remarkably. Under the experimental conditions,the proportions of NzO-N in denitrification are ranged from 0.25% to 6.35%. When the nitrogen transformation goes favorably, N20 emission period mainly occurs in SND during aerobic nitrification section in SBR. When the nitrogen transformation is inhibited,there are a large number of N20 emissions in aerobic nitrification section and anoxin nitrification section. And the microbial communities have a corresponding changes under different concentrations of NH4＋. The results indicate that N2O emission in wastewater denitrification is affected by not only the nitrogen conversion efficiency but also the changes in microbial community structures.