Cr~(6+)对活性污泥活性及有机物去除速率的影响

通过检测活性污泥系统的电子传递活性以及COD的去除速率,研究了Cr~(6+)对污泥活性以及有机物降解速率的影响,并探讨了两者之间的关系.研究结果表明:5 mg·L~(-1)的Cr~(6+)即会对系统产生明显影响,Cr~(6+)对污泥活性和COD去除率的抑制作用随其质量浓度的增大而增强;当Cr~(6+)质量浓度达到25 mg·L~(-1)时,污泥的INT和TTC-电子传递(TTC-ETS)活性以及有机物降解速率都表现为大幅的下降,下降比例分别为46.98%、54.18%以及64.47%.Cr~(6+)抑制污泥TTC-ETS活性的IC_(50)小于抑制INT-ETS活性的IC_(50),表明TTC-ETS活性反映Cr~(6+)毒性作用的灵敏性大于INT-ETS活性.此外,INT和TTC-ETS活性与有机物降解速率之间也均存在显著的正相关性,说明两者都是表征Cr~(6+)对有机物去除速率影响的灵敏参数.

Impacts of Cr~(6+)on the activity of activited sludge and the organic matter degradation rate

The impacts of Cr~(6+)on the activity and organic matter degradation rate of activited sludge, as well as relationship between them were studied by the determination of electron transport system(ETS) activity and COD removal rate. The results indicated that significant effects would occur when the dosage of Cr~(6+) is 5 mg/L. And the negative effects of Cr~(6+) on the activity and COD removal rate increased with the increase of Cr~(6+) concentration. In case of the Cr~(6+) concentration of 25 mg/L, the decreasing ratio of INT andTTC-ETS activity and the COD removal rate were 46.98%, 54.18%, and 64.47% respectively. The median inhibitory concentration(IC_(50)) of Cr~(6+) measured via TTC-electron transport system(TTC-ETS) activity was less than that of INT-electron transport system(INT-ETS) activity, indicating that the activity of INT-ETS to Cr~(6+) was less sensitive than that of TTC-ETS activity. Addtionally, significant positive correlations could be found between the organic matter degradation rate and the INT-ETS activity, as well as the TTC-ETS activity, in activated sludge system. Thus, the INT and the TTC-ETS activity were both effective parameters for characterizing the activity of activated sludge affected by Cr~(6+).