氨氧化菌混培物在O2/微量NO2下的氨氧化动力学

运用序批式试验，在无分子氧条件下，确定了好氧氨氧化菌的NO₂型氨氧化动力学方程，得到了最大氨氧化速率［q_NO2,max=0.144　mg·(mg·h)^-1］、二氧化氮半饱和常数(k_NO2=0.821 μmol·L^-1）和二氧化氮抑制性常数（k_i=1.721 μmol·L^-1）.在微量NO₂气体中添加2% O₂氧气后，氨氧化速率明显提高，最大氨氧化速率发生在体积分数2% O₂和50×10^-6 NO₂的条件下，达到0.198 　mg·(mg·h)^-1.在21%　O₂和微量NO₂条件下，氨氧化速率继续大幅度提高；在21%　O₂和100×10^-6　NO₂时氨氧化速率达到0.477 　mg·(mg·h)^-1，比无NO₂空气曝气条件下氨氧化速率高3倍.提出了NO₂表观强化氨氧化函数的概念，建立了在O₂和微量NO₂混合气体下的氨氧化动力学方程，利用2%　O₂和微量NO₂条件下的实验结果验证了动力学方程，讨论了NO₂强化氨氧化的机理.

Oxidation Kinetics of Ammonia Oxidizer Mixed Culture Under the Conditions of O2 and Trace NO2 Mixed Gasses

The kinetics of the NO2-dependent ammonia oxidation was developed for ammonia oxidizer mixed culture when there was no molecular oxygen in the batch tests. The kinetics parameters were determined, where the half saturate coefficient of NO2 was 0.821 micromol x L(-1), inhibition coefficient of NO2 concentration was 1.721 micromol x L(-1), and the maximum ammonia oxidation rate were 0.144 mg x (mg x h)(-1). After adding the volume fraction of O2 was 2% to trace NO2, the ammonia oxidation rates increased obviously. The maximum ammonia oxidation rate, 0.198 mg x (mg x h)(-1) occurred under the condition of the mixed gasses containing the volume fraction of O2 was 2% and 50 x 10(-6) NO2. Under the condition of mixed gasses containing the volume fraction of O2 was 21% to trace NO2, the ammonia oxidation rates further increased greatly. The maximum ammonia oxidation rate, 0.477 mg x (mg x h)(-1) occurred when the volume fraction of O2 was 21% and 100 x 10(-6) NO2 in the mixed gas, which is 3 times higher than the general aerobic ammonia oxidation rate. The function for NO2 apparently to enhance ammonia oxidation was suggested. The kinetics model of ammonia oxidation under the conditions of O2 and trace NO2 mixed gasses was developed. The model was validated by the results of ammonia oxidation experiments under the conditions of the mixed gasses containing 2% O2 and trace NO2. The mechanism for NO2 to enhance ammonia oxidation under the conditions of O2 and trace NO2 mixed gasses was discussed.