分段进水SBR短程生物脱氮过程中N_2O产生及控制

Formation and controlling of N_2O during short-cut biological nitrogen removal process using pulsed-feeding SBR

利用SBR,控制曝气量为60 L/h,利用在线pH曲线控制曝气时间,成功实现了短程生物脱氮过程,并考察了不同进水方式下SBR运行性能及N2O产量。结果表明,分段进水能够有效降低短程生物脱氮过程中外加碳源投加量。在原水进水碳氮比较低时,采用递增进水量的进水方式,能够有效降低生物脱氮过程中NO-2积累量,从而降低系统N2O产量。1次进水、2次等量进水和2次递增进水方式下,生物脱氮过程中N2O产量分别为11.1、8.86和5.04 mg/L。硝化过程中NO-2-N的积累是导致系统N2O产生的主要原因。部分氨氧化菌(AOB)在限氧条件下以NH+4-N作为电子供体,NO-2-N作为电子受体进行反硝化,最终产物是N2O。

Using a lab-scale batch sequencing reactor（ SBR）,advanced nitrogen removal from municipal wastewater and stabilizing short-cut nitrification and denitrification,as well as N2O emission,were investigated by on-line pH controlling. The aeration rate was controlled at 60 L/h. It revealed that by step-feeing pattern,less N2O was emitted and less external carbon for denitrification was required. The increasing feeding mode was efficient for reducing the NO-2 accumulation and N2O emission when organic carbon in the influent was insufficient. The N2O-N emission were 11. 1,8. 86 and 5. 04 mg/L for one-time feeding,two equal feeding and two increasing feeding mode respectively. The accumulation of NO-2-N during nitrogen removal process contributed to the production of N2O. The denitrification process of AOB under low DO level might be the cause of N2O production in which NO-2 was used as electron acceptor and NH＋4 as electron donor.