生物膜同步硝化反硝化脱氮过程中N_2O的产生量及机理分析

The N_2O Production and Mechanism Analysis of Simultaneous Nitrification and Denitrification in Biofilm Reactor

为了考察生物膜同步硝化反硝化脱氮过程中氧化亚氮(N2O)的释放量,以碳纤维为填料,采用SBR反应器研究了实际生活污水生物膜同步硝化反硝化过程中N2O释放量并对其产生机理进行了分析.在低溶解氧水平(0.2～1.5 mg/L)下系统同步硝化反硝化率维持在79%以上.在4个溶解氧水平0.2、0.4、1.0、1.5 mg/L下,每去除1 g氨氮N2O释放量分别为0.005、0.025、0.021、0.025 g,远低于短程硝化反硝化系统N2O释放量.1个反应周期内,N2O释放量随NH4+-N氧化而增加,NH4+-N氧化结束后,N2O释放量急剧减少.在曝气状态下,N2O释放速率与ρ(COD)呈现了较好的相关性.分析发现,生物膜同步硝化反硝化系统中N2O主要是由异养硝化和好氧反硝化产生.

Lab scale SBR （Sequencing Batch Reactor） filled with carbon fibre is used to investigate the N2O production of simultaneous nitrification and denitrifieation and the mechanism of the N2O production is also discussed. The results show that the efficiency of simultaneous nitrification and denitrification keeps above 79%. When Dissolved Oxygen （DO） is 0.2,0.4,1.0,1.5 mg/L, the N2O production is 0. 005,0. 025,0. 021,0. 025 g/g N-removed, respectively, which is lower than the production of short-cut nitrification. In one cycle, the N2O production increases with the oxidation of NH4^＋-N. When the oxidation of NH4^＋-N finished, the production of N2O decreases sharply. During aeration, the correlation between the N2O production rate and p（COD） concentration is found. After analysis, heterotrophic nitrification and aerobic denitrification are suggested to be the main source of N2O.