EPS对活性污泥絮凝沉降性能与表面性质的影响

采用序批式生物反应器（SBR）处理模拟废水，在葡萄糖作为碳源的条件下，调整进水碳源浓度改变系统内EPS含量，考察EPS的变化对活性污泥絮凝沉降性能及其表面性质的影响。结果表明，出水悬浮固体浓度（ESS）愈小，污泥絮体重絮能力（FA）越大，絮凝效果愈好。随着EPS的增加，ESS和污泥容积指数（SVI）升高，FA和ZSV降低，导致活性污泥絮凝性能和沉降性能下降。EPS与ESS呈正相关，EPS与FA呈负相关（R2分别为0.9916和-0.9941），EPS与SVI呈正相关性，EPS与区域沉降速率（ZSV）呈负相关性（R2分别为0.9451和-0.9805）。同时，EPS的增加对污泥表面性质产生重要影响，EPS的增加导致污泥表面Zeta电位下降，污泥相对疏水性RH逐渐降低。Zeta电位的下降和RH的降低直接引起SVI和ESS增大，导致污泥絮凝沉降性能下降。EPS总量与Zeta电位和RH的相关性系数R2分别为-0.99、-0.9979。

Effect of EPS on flocculation-sedimentation and surface properties of activated sludge

Effect of extracellular polymer substances(EPS)on flocculation-sedimentation and surface properties of activated sludge were investigated in a sequencing batch bioreactor(SBR)for treatment of simulated wastewater at various EPS concentration which was achieved by adjusting concentration of influent glucose as carbon source.The results show that when EPS is increased from 100 mg·L-1 to 500 mg·L-1,sludge volume index(SVI)is improved from 68.55 ml·g-1 to 164.35 ml·g-1,and suspended solids(ESS)in effluent from 4.4 mg·L-1 to 46.6 mg·L-1.There is positive correlation between EPS and ESS as well as SVI(R2 is 0.9916 and 0.9451,respectively).And meantime,the sludge floc weight capacity(FA)is decreased from 44.8% to 17.9% and regional subsidence rate(ZSV)from 11.2 m·h-1 to 3.2 m·h-1.There is negative correlation between EPS and FA as well as ZSV(R2 is-0.9941 and-0.9805,respectively).Furthermore,the sludge Zeta potential is decreased from-12.09 mV to-37.21 mV and relative hydrophobicity(RH)from 44.11% to 19.31%,and there is negative correlation between EPS and Zeta potential as well as RH(R2 is-0.9524 and-0.9979,respectively).