氨氮浓度对CANON工艺功能微生物丰度和群落结构的影响

Assessment of the Effect of Influent NH_4^+-N Concentration on the Abundance and Community Structure of Functional Bacteria in CANON Process

为了研究CANON工艺在常温低氨氮基质条件下的宏观运行效能及微观生态系统,通过调节曝气量和水力停留时间(HRT)实现了CANON工艺在不同进水氨氮浓度下的稳定运行,并基于PCR-DGGE和荧光定量PCR方法,分析了氨氮浓度对反应器中氨氧化细菌(AOB)和厌氧氨氧化菌(ANAMMOX菌)群落结构及丰度的影响.结果表明,较高氨氮环境中总氮去除负荷在1.0 g·(L·d)-1以上,当氨氮浓度降至100 mg·L-1时,总氮去除负荷明显降低.进水氨氮浓度对AOB的群落结构有重要影响,而对ANAMMOX菌群落影响较小.AOB和ANAMMOX菌的丰度随氨氮浓度的降低而减少,而亚硝酸盐氧化菌(NOB)的丰度随氨氮浓度的降低而增加,这可能是导致系统脱氮效果下降的主要原因.因此,需要通过一定的调控手段,减少AOB和ANAMMOX菌的损失,抑制NOB的生长,以便维持系统在低氨氮条件下的脱氮性能.

To investigate macroscopic performance and microcosmic ecosystem of CANON process in low ammonium concentration at room temprature,a steady-operation CANON reactor was achieved in different ammonium concentrations by adjusting aeration and hydraulic retention time（HRT）,and the effect of ammonium concentration on the abundance and community structure of functional bacteria was analyzed using PCR-DGGE and real-time PCR.The results indicated a high TN removal loading of over 1.0 g·（L·d）-1 in relatively high ammonium which was significantly reduced with the ammonium concentration of 100 mg·L-1.The community structure of ammonium oxidizing bacteria（AOB） changed sharply with the decrease of ammonium concentraion,which was not the same as anaerobic ammonium oxidizing bacteria（ANAMMOX bacteria）.Besides,the abundance of the two functional groups of bacteria reduced while the population of nitrite oxidizing bacteria（NOB） rose with the decrease of ammonium,which might be the main reason for the reduction of nitrogen removal efficiency.Consequently,some strategies are needed to reduce the loss of AOB and ANAMMOX bacteria and inhibit the growth of NOB so as to maintain the nitrogen removal performance in low ammonium concentration.