Abstract: Effect of extracelluler polymer substances (EPS) on the flocculation ability, settleability and surface properties of activated sludge were investigated using a sequencing batch bioreactor (SBR) to treat simulated wastewater when glucose was used as carbon source by adjusting influent concentration of carbon sources in order to change the EPS concentration. The results show that the sludge floc weight capacity (FA) and the flocculation are better when the effluent suspended solids (ESS) is more lower. ESS and sludge volume index (SVI) are increased, and FA and regional subsidence rate (ZSV) are decreased gradually with the increasing EPS, which could result in the lower activated sludge flocculation ability and settleability. EPS is positively correlated with the ESS and the SVI (R2 is 0.9916 and 0.9451, respectively) and EPS is negatively correlated with FA and the ZSV (R2 is -0.9941 and -0.9805, respectively). And furthermore, increasing EPS has an important impact on the surface properties of sludge. The sludge Zeta potential and the relative hydrophobicity (RH) of sludge are decreased when the EPS is improved, which can result in the increase of SVI and ESS and decrease of sludge flocculation ability and Settleability. EPS is negatively correlated with the Zeta potential and the RH (R2 is -0.99 and -0.9979, respectively).

Key words: extracellular polymeric substances, sequencing batch bioreactor, flocculation and settlement, surface properties

摘要： 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。

关键词: 胞外聚合物, 序批式生物反应器, 絮凝沉降性能, 表面性质