CANON工艺中N_2O的释放途径及影响因素

N_2O Release Pathways and Influencing Factors in CANON Process

N_2O是一种强温室气体,而污水脱氮是N_2O释放的重要人为源。污水生物脱氮过程不仅增加了N_2O的释放潜能,且极有可能从水中转嫁到大气中。CANON作为一种新型脱氮工艺,在处理高氨氮废水时有其独特的技术优势,已广泛用于实际污水处理中,但是进一步的研究发现,该脱氮过程中N_2O的释放量却不容乐观。在微生物机理上,分别从短程硝化、厌氧氨氧化以及反硝化阶段分析N_2O可能的产生途径,并对NH_4^+-N、NO_2^--N、曝气量等关键影响因素进行了讨论。在综合分析CANON中N_2O的产生机理和影响因素的基础上,提出优化系统运行控制条件,避免NO_2^--N的积累和低DO浓度,培养适应高NO_2^--N浓度的微生物种群,实现N_2O的减量化。

As a kind of powerful greenhouse gas, most of N2O could be released from nitrogen re- moval from wastewater. Wastewater biological nitrogen removal process not only increases the potential for N2O emission but also transfers N2O from wastewater to atmosphere. As a new denitrification process, CANON process has its unique technical advantages in the treatment of ammonia-rich wastewater. So it has been widely used in practical wastewater treatment field. While, CANON process could not be taken as a perfect technology for wastewater treatment due to a lot of N2O emissions. From the microbial bio- chemical transformation mechanism in CANON process, the N2O release pathways were investigated after analysis of the shortcut nitrification, denitrification and anaerobic ammonium oxidation stage. And then, the key factors such as NH4＋ - N, NO2- - N, aeration flow were discussed. After comprehensively ana- lyzed the mechanism and influencing factors of N2O emission from CANON, the optimal operating condi- tions of CANON were put forward to avoid NO2- - N accumulation and low level of DO. And furthermore, the functional microorganism population was cultivated to adapt to high NO2- -N concentration and to re- duce N2O.