Cu2+和S2-对反硝化污泥的影响

电镀废水中含络合铜废水的处理主要采用硫化钠破络法，由于原水水质波动，硫化钠投加量难以准确控制，从而导致Cu2+或S2-残留，对后续生物段运行会产生一定的影响。然而，针对这2种离子对反硝化污泥的影响尚未见系统报道。通过小试实验，系统研究了Cu2+和S2-对反硝化污泥的毒性和抑制作用，并通过长期实验考察了反硝化污泥对这2种离子的耐受程度以及污泥性质的变化。结果表明，Cu2+和S2-对反硝化污泥活性的EC50分别为3.15 mg·L-1和14.71 mg·L-1，在相同质量浓度下，Cu2+比S2-具有更强的毒性。长期运行实验结果表明，反硝化污泥对S2-具有一定适应能力，最大承受浓度为20 mg·L-1，而Cu2+耐受能力较差，最大承受浓度仅为1 mg·L-1。同时，Cu2+的连续投加使反硝化污泥的沉降性和脱水性能变差，比阻增大，而S2-的存在对反硝化污泥的沉降性和脱水性能无明显影响。

Influence of Cu2+ and S2- on denitrifying activated sludge

The sodium sulfide method is a key treatment strategy for chelated-copper compounds in electroplating wastewater that is a too complicated process for the complete removal of these compounds,reducing such toxic residues as Cu2+ or S2-. Both of these ions affect biochemical processes,but data on the influences of Cu2+ and S2- on denitrifying activated sludge are relatively scarce,even though these ions may degrade the system performance. In this study,we compared the toxicities and inhibitions of Cu2+ and S2- on denitrifying activated sludge. Moreover,the tolerance of Cu2+ and S2- and the sludge properties were studied by performing long-term experiments. The results showed that the median effective concentrations (EC50) of Cu2+ and S2- for denitrifying activated sludge were 3.15 mg·L-1 and 14.71 mg·L-1,respectively. The observed cumulative effects indicated that the maximum tolerance concentration of S2- for denitrifying activated sludge was 20 mg·L-1 higher than that of Cu2+ (1 mg·L-1). Moreover,the precipitation and dewatering were hindered more by the accumulation of Cu2+ than by the accumulation of S2-.