短程硝化启动运行中功能菌群变化研究

Variation of functional bacteria during start-up and operation of partial nitrification process

【目的】短程硝化-厌氧氨氧化是可实现的最短生物脱氮工艺,短程硝化是实现该工艺的重要环节和必要条件。【方法】采用序批式反应器(SBR)来实现短程硝化过程的启动和稳定运行,并对该过程中的相关功能菌群变化进行检测分析。【结果】通过控制低DO浓度(<1 mg/L)和逐步提高氨氮进水负荷,可抑制氨氧化细菌(NOB)菌群增殖并促进亚硝酸氧化菌(AOB)菌群规模显著扩大,实现短程硝化过程的启动和稳定运行。在氨氮进水负荷为0.055 kg/(m3.d)时,平均氨氮去除容积负荷和污泥负荷可达到0.043kg/(m3.d)和0.16 kg/(kg.d),平均亚硝酸盐积累率可达到83.4%。在短程硝化启动和稳定运行过程中,NOB菌群密度从2.0×105CFU/mL降至1.5×104CFU/mL,相对丰度从5.51%降至2.14%;AOB菌群密度从4.5×104CFU/mL增加至1.5×107CFU/mL,相对丰度从0.18%增加至7.25%。【结论】AOB菌群规模的扩大是实现短程硝化和氨氮去除能力提高的主要原因,同时较高的进水氨氮浓度和负荷也会造成亚硝化活性的抑制。

[Objective] Partial nitrification-anammox is considered as the shortest process for biological nitrogen removal and partial nitrification is the important part of this process.[Methods] The variation of functional bacteria during start-up and stable operation of partial ni-trification process was investigated in a SBR bioreactor in this study.[Results] The results indi-cated that ammonia-oxidizing bacteria（AOB） population was expanded significantly and ni-trite-oxidizing bacteria（NOB） population was inhibited when DO concentration was controlled lower than 1 mg/L and ammonia loading of the influent increased gradually.As a result,start-up and stable operation of partial nitrification process was realized.When ammonia volumetric loading of the influent was 0.055 kg/（m3？d）,the average ammonia removal volu-metric loading and sludge loading were 0.043 kg/（m3？d） and 0.16 kg/（kg？d）,respectively.In addition,the average nitrite accumulation rate was 83.4% at this time.AOB population density and relative abundance increased from 4.5×104 CFU/mL to 1.5×107CFU/mL and from 0.18% to 7.25%,respectively,during start-up and stable operation of partial nitrification process.At the same time,NOB population density and relative abundance decreased from 2.0×105 CFU/mL to 1.5×104 CFU/mL and from 5.51% to 2.14%,respectively.[Conclusion] The expansion of AOB population was responsible for realization of partial nitrification and ammonia removal.High am-monia concentration and loading also caused the activity inhibition of partial nitrification.