Cu^(2+)和Zn^(2+)对活性污泥生长动力学的影响

Growth kinetics of activated sludge in batch culture in the presence of Cu^(2+)and Zn^(2+)

Cu2 + 和 Zn2 + 是污水处理工艺中经常遇到的金属离子 ,文章利用序批式实验研究了活性污泥在 Cu2 +和 Zn2 + 作用下的生长模式。尽管微量的 Cu2 + 和 Zn2 + 对微生物的生长有益 ,但当它们达到一定的质量浓度时 ,均会对微生物的生长速率和 COD的去除速率产生抑制作用。实验结果表明 ,活性污泥的产量在 Cu2 + 的质量浓度为 1～ 2 0 mg/L时均有所减少 ;而 Zn2 + 的质量浓度只有超过 5 mg/L时 ,才能使污泥产量降低 ,当 Zn2 + 的质量浓度等于或低于 5 mg/L时 ,它反而轻微促进微生物的生长速率和 COD的去除速率。总体而言 ,根据微生物的比生长速率、基质比去除速率、活性污泥产率以及 COD的去除效率等各方面的对比研究 ,结果表明 ,Cu2 + 的毒性比 Zn2 +

The growth kinetics of activated sludge in batch culture in the presence of Cu^(2+)and Zn^(2+), which are the most common metal ions in wastewater treatment process,is investigated in this study. Though Cu^(2+) and Zn^(2+) in trace concentration are beneficial to the growth of microorganisms, they bring about inhibition effect on the growth kinetics at high concentration. Cu^(2+) inhibited the microorganism growth rate and the chemical oxygen demand(COD) removal rate,and consequently, decreased the yield of activated sludge at all tested concentration ranging from 1 mg/L to 20 mg/L. Zn^(2+) inhibited the microorganism growth rate, the COD removal rate and the yield of activated sludge at concentration over 5 mg/L; but at 5 mg/L, or less, it enhanced the microorganism growth rate and the COD removal rate slightly. Overall, Cu^(2+) was more toxic than Zn^(2+) according to their effect on the relative specific growth rate of microorganisms,the relative specific COD removal rate,the yield of activated sludge as well as the COD removal efficiency.