酸性条件下NO_(2)-型反硝化富集N_(2)O的影响因素  

Factors Influencing Nitrous Oxide Enrichment during Nitrite Denitrification under Acidic Conditions

作　　者：孔海霞 吝力 吕永涛[2,3] 朱传首 张旭阳 王磊 KONG Hai-xia;LIN Li;LüYong-tao;ZHU Chuan-shou;ZHANG Xu-yang;WANG Lei(Xi’an Branch,North China Municipal Engineering Design&Research Institute Co.Ltd.,Xi’an 710018,China;School of Environmental and Municipal Engineering,Xi’an University of Architecture and Technology,Xi’an 710055,China;Key Laboratory of Membrane Separation of Shaanxi Province,Research Institute of Membrane Separation Technology of Shaanxi Province,Xi’an 710055,China)

机构地区：[1]中国市政工程华北设计研究总院有限公司西安分公司,陕西西安710018 [2]西安建筑科技大学环境与市政工程学院,陕西西安710055 [3]陕西省膜分离技术研究院陕西省膜分离重点实验室,陕西西安710055

出　　处：《中国给水排水》2024年第23期57-63,共7页China Water & Wastewater

基　　金：陕西省重点研发计划项目(2022SF-268);陕西省重点产业链(群)项目(2022ZDLSF06-05)。

摘　　要：N_(2)O是潜在的可再生能源,反硝化过程中N_(2)O的富集可为其能源回收提供依据。接种反硝化污泥后,通过降低进水pH至5.0,7.17%的NO_(2)-可转化为N_(2)O。在此基础上,利用批式试验分析了酸性条件(pH为5.0~7.0)和NO_(2)-浓度(10~90 mg/L)对反硝化及N_(2)O释放的影响。结果表明,随着pH的降低及游离亚硝酸(FNA)浓度的升高,N_(2)O净产率均呈现先升后降的趋势,当pH为5.8且NO_(2)-浓度为50 mg/L时(FNA为0.84 mg/L),N_(2)O转化率达到最大值42.56%。利用微电极进一步研究发现,在pH为5.5~7.0条件下,N_(2)O的还原速率随pH的降低及FNA浓度的升高呈降低趋势,且当存在FNA时,降低的幅度增大。综上,酸性条件和FNA均能抑制N_(2)O还原酶的活性,且后者是主要抑制剂。因此,过低的pH及过高的FNA浓度抑制了N_(2)O的产生,导致其净产率下降。Nitrous oxide(N_(2)O)represents a promising renewable energy source,and the accumulation of N_(2)O during the denitrification process can serve as a foundation for its energy recovery.Following the inoculation of the denitrifying sludge,7.17%of nitrite was transformed into N_(2)O by reducing the influent pH to 5.0.Building upon this foundation,the impacts of acidic conditions(pH 5.0-7.0)and nitrite concentration(10-90 mg/L)on denitrification and N_(2)O emissions were systematically evaluated through batch experiments.As pH decreased and free nitrous acid(FNA)increased,the net production rate of N_(2)O initially rose before subsequently declining.At a pH of 5.8 and a nitrite concentration of 50 mg/L(with FNA at 0.84 mg/L),the N_(2)O conversion rate peaked at 42.56%.Subsequent investigations utilizing microelectrodes revealed that the reduction rate of N_(2)O diminished as the decrease of pH and the increase of FNA concentration within the range of pH 5.5 to 7.0,and a more pronounced decrease observed in the presence of FNA.In summary,both acidic conditions and FNA served as inhibitors of N_(2)O reductase activity,with the latter identified as the primary inhibitor.Consequently,excessively low pH and elevated FNA concentration impeded the production of N_(2)O,leading to a reduction in its net production rate.

关 键 词：反硝化 酸性条件 游离亚硝酸 氧化亚氮 

分 类 号：TU992[建筑科学—市政工程]