碱性印染废水的pH对活性污泥的影响及其控制

Control and Effects of pH of Printing and Dyeing Wastewater on Activated Sludge

采用好氧活性污泥法处理高pH(9.10-12.59)的印染废水，以活性污泥有效负荷的变化反映活性污泥降解有机物能力的变化，以污泥沉比、污泥容积指数和出水悬浮物浓度的变化反映活性污泥絮凝性能的变化。试验条件下，进水pH≤10．5不会对活性污泥性能产生明显抑制；进水pH≥11．1、水力停留时间（HRT）＜16h时，活性污泥性能受到抑制，污泥出现离散，通过延长HRT可以减轻或消除抑制；进水pH11.6，即使HRT达到24h，也不能消除抑制。通过调节进水pH,增大HRT等措施，控制混合液的pH小于9．4，则可避免因pH过高而导致的活性污泥抑制。得出因pH变化而导致的活性污泥离散模型，据此可判断污泥的活性及其变化趋势。

Aerobic activated sludge oxidation was utilized to treat printing and dyeing industrial wastewater with high pH (9.10~12.59) in a lab-scale experiment. Effective sludge loading (SL) was applied to indicate the degradation capacity of activated sludge, while the ratio of sludge volume with mixed liquor(SV), sludge volume index (SVI) and effluent suspended solid (SS) were used to describe the sludge flocculability. Under the experiment conditions, influent pH≤10.5 had hardly any effects on the activated sludge, which began to disperse and be inhibited under the conditions of influent pH≥11.1 and HRT<16h. Sludge bulking resulted from high pH could be avoided by adjusting influent pH and prolonging HRT to control mixed liquor pH below a limit of 9.4. However, it could not be avoid even HRT was over 24h under influent pH 11.6. A physical model was present to describe activated sludge dispersion resulted from high influent pH. The model, in which four stages of activated sludge development was divided, can be used to analyze sludge activity and sludge degradation.