化工学报 ›› 2015, Vol. 66 ›› Issue (3): 1133-1141.DOI: 10.11949/j.issn.0438-1157.20141165

• 能源和环境工程 • 上一篇    下一篇

短程硝化过程中NO2-对NH4+及NH2OH氧化产生N2O的影响

刘越1, 彭轶1, 李鹏章1, 侯红勋2, 彭永臻1   

  1. 1 北京工业大学北京市水质科学与水环境恢复工程重点实验室, 北京市污水脱氮除磷处理与过程控制工程技术研究中心, 北京 100124;
    2 安徽国祯环保节能科技股份有限公司, 安徽 合肥 230088
  • 收稿日期:2014-08-01 修回日期:2014-11-06 出版日期:2015-03-05 发布日期:2015-03-05
  • 通讯作者: 彭永臻
  • 基金资助:

    住建部2014年科学技术项目计划(2014-K7-022);高等学校博士学科点专项科研基金(优先发展领域)项目(20111103130002)。

Effect of NO2- on N2O production by NH4+ and NH2OH oxidation during nitritation process

LIU Yue1, PENG Yi1, LI Pengzhang1, HOU Hongxun2, PENG Yongzhen1   

  1. 1 Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, China;
    2 Anhui Guozhen Environmental Protection Energy-saving Technology Limited Liability Company, Hefei 230088, Anhui, China
  • Received:2014-08-01 Revised:2014-11-06 Online:2015-03-05 Published:2015-03-05

摘要:

N2O是一种强效的温室气体,而污水生物脱氮过程是N2O产生的一个主要人为来源。在本研究中,向生物处理出水中投加NH4+、NH2OH及NO2-,研究了NO2-对NH4+及NH2OH氧化过程中N2O产生的影响。试验结果表明,NH4+及NH2OH氧化过程的最初30 min内(总反应时间180 min)产生的N2O占总N2O产生量的25%以上。在NH4+或NH2OH氧化完成前的30 min内,N2O的净产生量仅有0.2 mg·L-1。NH2OH的氧化是短程硝化开始阶段产生N2O的途径,此后NH4+或NH2OH氧化为AOB提供还原NO2-电子,引起的反硝化作用是产生N2O的主要途径。在实际生活污水短程硝化试验过程中,由于部分COD的存在,在低氧条件下,可能会出现异养菌的反硝化作用。同时,由于氧气及NO2-对氧化亚氮还原酶(NOS)的抑制,使得在生活污水进行短程硝化时,N2O的净产量比上述出水试验时增加了17%以上,总产量最高达到了11.07 mg·L-1。这一途径对N2O产生的贡献也是不容忽视的。

关键词: 短程硝化, NO2-, NH2OH氧化, 异养反硝化

Abstract:

Nitrous oxide (N2O) is one of the most important greenhouse gases, about 265 times stronger than carbon dioxide (CO2), and it may also destroy the ozone layer. In the biological wastewater treatment process, autotrophic nitrification has been thought to be the major source of N2O production. So it becomes increasingly important to prevent N2O emission from sewage treatment. In this study, by adding NH4+, NH2OH and NO2- to the effluent, the effect of NO2- on N2O production by NH4+ and NH2OH oxidation during the nitritation process was investigated in a laboratory batch-scale system with activated sludge for treating domestic wastewater. Within the first 30 min of NH4+ and NH2OH oxidation process (total test time:180 min) N2O accounted for more than 25% of the total production. As NH4+ or NH2OH was consumed completely, the amount of N2O net production reduced to less than 0.2 mg·L-1 in the last 30 min. Furthermore, the concentration of NO2--N could affect N2O production. The increase of NO2--N would promote generation of N2O. The maximum total N2O net production was 6.86 mg·L-1 when the concentration of NO2- was 60 mg·L-1. NH2OH oxidation played a key role in N2O production at the very beginning of the experiment while nitrifier denitrification became a main pathway later. When the domestic sewage was treated under DO limited conditions, due to the presence of COD, there might occur heterotrophic denitrification during the aeration phase. However, oxygen and NO2- had strong inhibition on the activity of nitrous oxide reductase (NOS), consequently N2O could not be reduced to N2 completely. It led to more than 17% N2O was produced and the maximum total net production reached 11.07 mg·L-1. Hence, the contribution to N2O produced by denitrification could not be ignored during the domestic wastewater treatment. Besides co-existence of NH4+ and NH2OH could significantly increase N2O production and this process also emitted more N2O when the concentration of NO2- was increased.

Key words: nitritation process, nitrite, NH2OH oxidation, heterotrophic denitrification

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