生活污水短程生物脱氮过程中N2O的产生与控制方法

 为降低和控制实际污水处理厂中N2O产生量,通过长期试验和间歇试验对SBR法实际生活污水全程及短程脱氮过程中N2O的主要产生源和影响因素进行了研究.结果表明:生活污水短程硝化反硝化过程中有N2O产生,并且N2O主要产生于短程硝化过程中,即氨氧化过程中,而反硝化作用没有N2O产生,且能够将氨氧化结束时,活性污泥中累积的溶解性N2O进一步还原为N2.短程硝化过程中,N2O产生量随进水氨氮浓度的升高而显著增加.DO浓度对N2O的产生与释放有重要的影响,DO浓度高于2mg/L和低于0.5mg/L N2O产生量均较低.DO低于0.5mg/L时,一方面,降低了曝气作用对N2O的吹脱,延长了N2O在活性污泥中的停留时间;另一方面,在活性污泥絮体内部形成缺氧区,促进了同步硝化反硝化,在硝化作用的同时,加强了反硝化作用对N2O的还原作用,利于N2O的减量控制.

N2O sources and control methods during nitrogen removal from domestic wastewater

To reduce and control of N2O production during wastewater treatment plant, both long-term and batch tests were carried out to investigate main source and pathway of N2O production during nitrogen removal via nitrite from real domestic wastewater in SBR. N2O was produced during nitrogen removal via nitrite from domestic wastewater. N2O was mainly produced during nitritition; whereas, heterotrophic denitrifiers did almost not produced N2O. Furthermore, anoxic denitrification might have the potential of reducing N2O production. During nitritition, N2O production increased obviously with the increase of the influent ammonia concentration. DO concentration also significantly influenced N2O production during nitritition. N2O production were very low when DO concentration were controlled higher than 2mg/L or lower than 0.5mg/L. DO concentration lower than 0.5mg/L reduced N2O stripping of aeration and prolonged the N2O retention time in the activated sludge. Moreover, N2O reduction was enhanced under the DO concentrations lower than 0.5mg/L due to denitrification can be accrued in the anoxic zone of the activated sludge floc.