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基于同位素技术的短程硝化过程N2O产生途径

本站小编 Free考研考试/2021-12-31

中文关键词溶解氧短程硝化氨氧化菌N2O同位素 英文关键词dissolved oxygenpartial nitrificationammonia-oxidizing bacteriaN2Oisotope
作者单位E-mail
杨玉兵北京工业大学环境与能源工程学院, 城镇污水深度处理与资源化利用技术国家工程实验室, 北京 10012418810358155@163.com
杨庆北京工业大学环境与能源工程学院, 城镇污水深度处理与资源化利用技术国家工程实验室, 北京 100124yangqing@bjut.edu.cn
李洋北京工业大学环境与能源工程学院, 城镇污水深度处理与资源化利用技术国家工程实验室, 北京 100124
周薛扬北京工业大学环境与能源工程学院, 城镇污水深度处理与资源化利用技术国家工程实验室, 北京 100124
李健敏北京工业大学环境与能源工程学院, 城镇污水深度处理与资源化利用技术国家工程实验室, 北京 100124
刘秀红北京工业大学环境与能源工程学院, 城镇污水深度处理与资源化利用技术国家工程实验室, 北京 100124
中文摘要 在常温条件下,采用批次试验结合同位素分析技术,研究不同溶解氧(DO)浓度下短程硝化过程N2O的释放量及产生途径.结果表明,不同溶解氧条件下,N2O的释放量与NO2--N浓度显著相关,当NO2--N浓度大于3 mg·L-1,短程硝化过程开始出现N2O的释放,且随着NO2--N浓度的增加而增加.当溶解氧浓度分别为0.5、1.5和2.5 mg·L-1时,N2O的释放量占进水总氮的比例分别为4.35%、3.27%和2.63%,随着溶解氧的升高,N2O的释放量占进水总氮的比例降低.短程硝化过程控制溶解氧在2.5 mg·L-1,既可以提高比氨氧化速率,又可以减少N2O的产生.同位素测定结果表明,当溶解氧为0.5 mg·L-1时,只有AOB反硝化过程生成N2O.但当溶解氧升至1.5 mg·L-1时,有4.52%的N2O通过NH2OH氧化过程生成,AOB反硝化过程生成的N2O占95.48%.继续升高溶解氧到2.5 mg·L-1时,NH2OH氧化过程生成的N2O比例增加至9.11%,AOB反硝化过程生成的N2O占90.89%,溶解氧浓度的改变会影响短程硝化过程N2O的产生途径,避免过高的NO2--N积累,可以减少N2O的产生. 英文摘要 Batch experiments were conducted under normal temperature conditions to study the generation of N2O in the partial nitrification process under different dissolved oxygen concentrations and their production pathways. When dissolved oxygen was 0.5, 1.5, and 2.5 mg·L-1, the proportion of N2O released into the total nitrogen input was 4.35%, 3.27%, and 2.63%, respectively. With increase dissolved oxygen, the proportion of N2O released to total influent nitrogen was reduced. Isotope measurements showed that when dissolved oxygen was 0.5 mg·L-1, only denitrification by ammonia-oxidizing bacteria (AOB) produced N2O. However, when dissolved oxygen increased to 1.5 mg·L-1, the activity of nitrifying bacteria increased, and 4.52% of N2O was generated through a hydroxylamine oxidation process, whereas the N2O generated by AOB denitrification accounted for 95.48%. When dissolved oxygen continuously increased to 2.5 mg·L-1, the proportion of N2O produced by hydroxylamine oxidation increased to 9.11%, and the N2O generated by AOB denitrification accounted for 90.89%. The change in dissolved oxygen concentration affects the N2O production pathway in the short-cut nitrification process, and avoiding excessive NO2--N accumulation can reduce the production of N2O.

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