Cu2+、Zn2+对生物脱氮系统的影响

Cu²⁺和Zn²⁺是污水处理工艺中经常遇到的金属离子。在驯化好的活性污泥系统中，研究了金属离子Cu²⁺和Zn²⁺在0～100 mg/L浓度下对活性污泥生物脱氮系统的影响。试验发现Cu²⁺＞5 mg/L、Zn²⁺＞30 mg/L时，对硝化过程具有明显的抑制作用，在同样浓度的试验条件下Cu²⁺对硝化过程的抑制作用比Zn²⁺大。Cu²⁺≤0.5 mg/L时对反硝化过程具有一定的促进作用，有助于提高TN的去除效果；Cu²⁺＞0.5 mg/L时，对反硝化产生抑制作用，随着浓度的增加，TN去除率逐渐下降。Zn²⁺不影响反硝化过程，仅在大于30 mg/L时，对硝化过程产生抑制作用。重金属Cu²⁺对生物脱氮系统的影响明显强于Zn²⁺。

Effects of Cu2+ and Zn2+ on the biological nitrogen removal system

Cu²⁺and Zn²⁺ are the most common metal ions in wastewater treatment process. In this paper, the effects of Cu²⁺ and Zn²⁺ on the biological nitrogen removal system have been assessed for a range of metal ion concentration from 0 to 100 mg/L on the basis of good activated sludge system. When Cu²⁺ was more than 5 mg/L and Zn²⁺ was more than 30 mg/L, which was found to have inhibiting effect on biological nitrogen based on tests. Tests were performed on the same concentrations of ion, it was found that the inhibitory effect on nitrification of Cu²⁺ was stronger than Zn²⁺. Copper had some promoting effect on denitrification while Cu²⁺ was less than 0.5 mg/L and was helpful to improve the removal rate of TN. But when Cu²⁺ was more than 0.5 mg/L, the inhibitory effect on denitrification may be produced by copper. The removal rate of TN would gradually decrease with the increase of concentration of Cu²⁺. Zinc showed no inhibitory effect on denitrification, but inhibitory effect on nitrification at the concentrations of Zn²⁺ above 30 mg/L. The results revealed that the effect of Cu²⁺ on the biological nitrogen removal system was stronger than that of Zn²⁺.