乙酸钠为碳源时的污水反硝化规律研究

Characteristics of Denitrification Process with Sodium Acetate as Sole Carbon Source

利用序批式反应器,以CH3COONa为唯一碳源,对反硝化污泥进行了50 d的长期驯化。之后,利用缓冲溶液将反硝化过程中pH值的上升幅度控制在0.5范围内,研究了不同碳氮比下的反硝化规律。结果表明,无论碳源是否充足,反硝化过程中硝酸盐氮和亚硝酸盐氮的变化趋势基本相同,即反硝化过程中均会出现亚硝酸盐氮积累且随后逐渐消失的现象。硝酸盐氮还原完毕时,亚硝酸盐氮会出现最大积累量,同时反硝化速率出现拐点,速率开始明显加快。当碳氮比从1.0增加到3.7时,反硝化速率明显增加。反硝化菌可过量吸附CH3COONa,因此在以CH3COONa为外加碳源进行反硝化时,即使CH3COONa投加过量,出水COD值也能维持在较低水平。

Activated sludge for denitrification was incubated for 50 days with sodium acetate as the sole carbon source in a sequencing batch reactor. The characteristics of denitrification process were studied under different carbon/nitrogen ratios with buffer solution adding to control the variation of pH in the range of 0.5. The results show that trends of nitrate nitrogen and nitrite nitrogen changes during denitrification are the same under different carbon/nitrogen ratios. Nitrite nitrogen is accumulated and disappeares during denitrification. When nitrate reduction is finished, the amount of accumulated nitrite nitrogen reaches its climax. Meanwhile, a point of inflection for denitrification occurs, and the denitrification rate becomes greatly increased. When the carbon/nitrogen ratio is increased from 1.0 to 3.7, the denitrification rate is significantly increased. During denitrification, sodium acetate is adsorbed excessively. This indicates that even superfluous sodium acetate is added into a denitrification reactor as external carbon source, COD concentration can keep low in the effluent.