The effectiveness of enhancing treatment of water with low turbidity through combined effects of potassium permanganate oxidation, PAM aiding coagulation and sludge recycling was investigated through continuous bench scale studies. Additionally, the mechanism of pollutant removal was discussed. Comparing with ferric chloride coagulation,only recycling sedimentation sludge was ineffective in enhancing treatment of water with low turbidity. PAM with recycled sludge showed positive effects, and the additional potassium permanganate dosing exhibited the best potential of favoring coagulation. It was observed that the optimal potassium permanganate dosage was 0. 4 mg/L. SEM analysis indicated that the floes were loosely formed and the particle diameter was critically low for ferric chloride coagulation process. Comparatively, the addition of PAM and potassium permanganate with recycled sludge facilitated the aggregation of tinny particles onto compact PAM polymer chains, therefore contributing to the formation of compact floes with high particle diameter. The combined employment of recycled sludge, PAM and potassium permanganate showed the best potential of favoring coagulation, mainly through synergistic effects between seeding, polymer bridging and increasing effective collision in mechanism.%通过动态试验考察了高锰酸钾、PAM、回流污泥组合应用强化低浊水处理的效能,并探讨了组合工艺对水中污染物的的去除机制.与投加三氯化铁相比,单纯将沉淀污泥回流不能有效改善低浊水处理效果；将回流污泥和PAM同时投加可以改善处理效果；在投加回流污泥和PAM时,投加KMnO4 可进一步改善混凝效果,KMnO4最佳投加量为0.4 mg/L.电镜扫描结果显示单纯三氯化铁絮凝所形成的絮体粒径小且结合松散,而PAM、KMnO4、回流污泥组合应用可以使许多细小颗粒彼此聚合,絮体粒径增大并且结合致密.从理论上论证了回流污泥、PAM、KMnO4组合应用主要是通过絮凝核心、聚合体架桥、颗粒碰撞等的协同作用来改善混凝效果.
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