基于同位素技术的短程硝化过程N_2O产生途径  

N_2O Production Pathways in Partial Nitrification Based on Isotope Technology

作　　者：杨玉兵 杨庆 李洋 周薛扬 李健敏 刘秀红 YANG Yu-bing, YANG Qing, LI Yang, ZHOU Xue-yang, LI Jian-min, LIU Xiu-hong(National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124, China)

机构地区：[1]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

出　　处：《环境科学》2018年第11期5051-5057,共7页Environmental Science

基　　金：北京市自然科学基金项目(8182012)

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N_2O的释放量及产生途径.结果表明,不同溶解氧条件下,N_2O的释放量与NO_2^--N浓度显著相关,当NO_2^--N浓度大于3 mg·L^(-1),短程硝化过程开始出现N_2O的释放,且随着NO_2^--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,N_2O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,N_2O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N_2O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N_2O.但当溶解氧升至1. 5 mg·L^(-1)时,有4. 52%的N_2O通过NH_2OH氧化过程生成,AOB反硝化过程生成的N_2O占95. 48%.继续升高溶解氧到2. 5 mg·L^(-1)时,NH_2OH氧化过程生成的N_2O比例增加至9. 11%,AOB反硝化过程生成的N_2O占90. 89%,溶解氧浓度的改变会影响短程硝化过程N_2O的产生途径,避免过高的NO_2^--N积累,可以减少N_2O的产生.Batch experiments were conducted under normal temperature conditions to study the generation of N2 O 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 N2 O released into the total nitrogen input was 4. 35%,3. 27%,and 2. 63%,respectively.With increase dissolved oxygen,the proportion of N2 O 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 N2 O. However,when dissolved oxygen increased to 1. 5 mg·L^-1,the activity of nitrifying bacteria increased,and 4. 52% of N2 O was generated through a hydroxylamine oxidation process,whereas the N2 O generated by AOB denitrification accounted for 95. 48%. When dissolved oxygen continuously increased to 2. 5 mg·L^-1,the proportion of N2 O produced by hydroxylamine oxidation increased to 9. 11%,and the N2 O generated by AOB denitrification accounted for 90. 89%. The change in dissolved oxygen concentration affects the N2 O production pathway in the short-cut nitrification process,and avoiding excessive NO2^--N accumulation can reduce the production of N2 O.

关 键 词：溶解氧 短程硝化 氨氧化菌 N2O 同位素 

分 类 号：X703[环境科学与工程—环境工程]