pH值对零价铁自养反硝化过程的影响

以零价铁和硝酸盐为基质,通过批量实验和连续流发酵罐实验中铁自养反硝化脱氮速率的测定,研究了铁自养反硝化过程pH值的变化以及pH值对零价铁自养反硝化污泥活性的影响.批量实验采用4个添加污泥的反应瓶,初始pH值分别为6.2、6.7、7.5、8.8和一个初始pH为6.7的未添加污泥瓶.结果表明初始pH值6.7时表现出最高氮素脱除速度,其中未添加污泥的批量瓶pH持续上升至10左右,4个不同初始pH添加污泥的批量瓶的pH值后续均集中在7.5~7.8之间,难以凸显不同pH值对反硝化菌的影响.利用能够控制pH值稳定的连续流发酵罐,通过设立6、6.5、7、7.5、8这5个恒定的pH梯度,对微生物不同pH值条件下的适应性和活性进行观察,结果表明在pH为6.5时污泥活性最大,其氮脱除速率达到1.35mg·(L·h)~(-1).

Effect of pH Value on Autotrophic Denitrification Process of Zero Valent Iron Substrate

Using a substrate with zero valent iron and nitrate, the research determined the change of pH value in the iron autotrophic denitrification process and the effect of pH on zero valent iron autotrophic denitrification activated sludge using batch experiments and a continuous flow fermenter denitrification rate. Batch experiments were carried out with four reactor bottles with sludge addition. The initial pH values were 6.2, 6.7, 7.5, and 8.8, respectively, and there was an initial pH of 6.7 in a bottle without sludge addition. The results showed that the initial pH value of 6.7 obtained the highest nitrogen removal rate. For the bottle without sludge addition, the pH rose to about 10. The pH value of the four batch experiments was concentrated between 7.5-7.8 in the follow-up process, so there was no significant difference in the effects of pH on denitrifying bacteria. However, the pH value in the fermenter can be controlled stably by an acid-base pump. With five pH gradients of 6, 6.5, 7, 7.5, and 8, the adaptability and activity of microorganisms under a constant pH value were observed separately. The sludge activity was the highest at pH 6.5, and the highest nitrogen removal rate was 1.35 mg·(L·h)^-1.