中文摘要：

采用4个平行的序批式反应器，研究了不同pH下活性污泥絮体表面特性和形态结构的变化。结果表明：酸性条件下（pH=4．0，5．5）污泥产生的胞外聚合物总量较多，其中多糖和蛋白质的含量远大于中性（pH=7．0）和偏碱性条件（pH=9．0）。污泥表面Zeta电位随pH的升高而降低；pH对污泥相对疏水性的影响规律并不明显，EPS组成比例较EPS总量本身更易影响污泥表面相对疏水性；此外，在酸性条件下，丝状菌大量生长，导致污泥絮体的平均粒径增大，并且呈现双峰粒径分布，絮体分形维数较低，结构松散；在中性条件下，无明显丝状菌生长，絮体平均粒径减小，分形维数较高，结构致密：偏碱件条件下．吊然沿右出现大量丝状菌，但絮体平均粒径较中性条件略有增大，分形维数相应减小。

英文摘要：

The effect of pH on surface properties and physical structure of activated sludge flocs forming in four sequencing batch reactors was studied. The results show that the amount of EPS at acid condition （pH = 4.0,5.5） is dramatically higher than those of neutral condition （ pH = 7.0） and alkali condition （ pH = 9.0）, especially polysaccharide and protein. Furthermore, Zeta potential of flocs decrease with pH remarkably. Relative hydrophobicity （RH） is not affected by pH evidently, and the proportion of EPS components is more important than the amount for determining RH of sludge flocs. Filamentous microorganisms predominating and resulting in a large flocs size with two peak size distribution at lower pH have been observed by SEM images. Meanwhile, the porous flocs structure with lower fractal dimension form at acid conditions than those forming under higher pH condition. No obvious filamentous microorganisms have been observed at high pH.