科研之友
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摘要
The aim of this study is to evaluate the effectiveness of dehydrogenase activities as an early warning indicator in wastewater treatment process under the impact of Cu(II). The substrate removals in sequencing batch reactors (SBR) on different Cu(II) concentrations (0, 5, 10, and 20 mg L-1) were investigated during long-term operation. Meanwhile, the dehydrogenase activities of activated sludge taken from SBR were observed in short-term bioassays. The results indicate that the inhibitory rates of Cu(II) on substrate removal efficiencies increased along with an increment of Cu(II) concentration. The dehydrogenase activities demonstrated similar trend. Logarithmic curves were used to describe the inhibitory effect of Cu(II) on dehydrogenase activities. Positive correlations were then obtained between the substrate removal efficiencies during long-term operation and dehydrogenase activities in short-term bioassays. Thus, 2-(p-iod-phenyl)-3-(p-nitrophenyl)-5-phenyltetrazolium chloride (INT)-dehydrogenase activity test can be applied as an effective method to alert the activated sludge system performance under the impact of heavy metal. In addition, median inhibitory concentration (IC50) by INT-dehydrogenase test after 1-h and 24-h Cu(II) exposure (5.93 mg L-1 for 1 h exposure and 5.45 mg L-1 for 24 h exposure) were obtained. These results showed that IC50 after 24 h of Cu(II) exposure appeared more sensitive to copper than that after 1 h. Therefore, INT-dehydrogenase test after 24 h Cu(II) exposure could be better fit for the early warning of wastewater treatment performance.
