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污染控制技术及原理

Nitrite accumulation during denitrification with quinoline or indole as the sole carbon source

摘要：分别以喹啉或吲哚为单一碳源和电子供体,硝酸盐为电子受体,对反硝化过程中亚硝酸盐(NO₂^--N)的积累进行了试验研究.结果表明,以喹啉为碳源时,在不同碳氮比(C/N)条件下反硝化过程中均出现明显的NO₂^--N积累;而且其最高积累率随着C/N比增大而降低,当C/N比为2.5时,NO₂^--N最高积累率达93.97%,当C/N比为12.8时NO₂^--N最高积累率为42.31%.而以吲哚为碳源时,在不同C/N比条件下反硝化过程中NO₂^--N积累程度都很低,最高积累率只有4.71%.以喹啉为单一碳源时,亚硝酸盐的还原速率小于硝酸盐的还原速率;而以吲哚为单一碳源时,亚硝酸盐的还原速率大于硝酸盐的还原速率;上述硝酸盐与亚硝酸盐还原速率的不同导致了以喹啉或吲哚分别为碳源时反硝化过程中亚硝酸盐积累率的不同.基于碳源完全降解和完全反硝化的考虑,以喹啉或吲哚为单一碳源时的最佳碳氮比均为6.8.

Abstract：Batch experiments were conducted to investigate nitrite(NO₂^--N) accumulation during denitrification with quinoline or indole as the sole carbon source and electron donor and nitrate(NO₃^--N) as the electron acceptor.Significant NO₂^--N accumulation was observed at all tested C/N ratios when quinoline was used as the sole carbon source,and the maximum NO₂^--N accumulation percentage decreased with the increase of C/N ratio.While the maximum NO₂^--N accumulation percentage reached 93.97% at C/n=2.5,it was only 42.31% at C/n=12.8 when quinoline was used as the sole carbon source.In contrast,NO₂^--N scarcely accumulated when indole was used as the sole carbon source,and the highest NO₂^--N accumulation percentage was only 4.71% at all tested C/N ratios.The nitrite reduction rate was lower than the nitrate reduction rate when quinoline was used as the carbon source,whereas the former was greater than the latter when indole was used as the carbon source.Different reduction rates between nitrate and nitrite led to the different nitrite accumulation percentages during denitrification with quinoline or indole as the sole carbon source.Based on complete degradation of the carbon source and complete denitrification,the optimal C/N ratio was 6.8 when quinoline or indole was used as the sole carbon source.