[目的]探讨超声波对污泥脱水性能的影响及其机理.[方法]以城市生活污水处理厂的剩余活性污泥为研究对象,对超声波处理时间和声能密度对污泥脱水性能的影响进行研究,并初步探讨超声波改善污泥脱水性能的机理.[结果]随着超声波处理时间的增加,污泥颗粒粒径逐渐变小,污泥CST呈先减小后增大趋势,当超声时间为8 8时达最小值(75.7 s),污泥滤液COD值呈明显上升趋势；随着声能密度的增大,污泥颗粒粒径逐渐变小.但超声时间过长和声能密度过大均可导致污泥脱水性能变差.超声波改善污泥脱水性能可能是由于超声波通过调整污泥结构,促使污泥结构重组,改变污泥中水的存在形态,使污泥中难去除的结合水释出,从而转化成易脱的自由水所致.[结论]该研究可为超声波的工业应用提供一定的理论依据.%[Objective] The aim was to study the effects of ultrasonic on the dehydration function of sludge and internal mechanism. [Meth od ] Taking the residual sludge from a municipal domestic sewage treatment plant as the study object, die effects of ultrasonic time and sound energy density on the dehydration function of sludge were studied firstly, then the internal mechanism of improvement of sludge dehydration function by ultrasonic was discussed. [Result] As the increase of ultrasonic time, sludge particles became smaller, and COD of sludge filtrate went up obviously; meanwhile, the capillary suction time (CST) of sludge increased firstly and then decreased, and the minimum value (75.7 s) appeared when ultrasonic time was 8 s. With the raising of sound energy density, the size of sludge particles went down gradually. Howev er, the over much ultrasonic time and high sound energy density could decrease the dehydration function of sludge. For the possible mechanism of improvement of sludge dehydration function by ultrasonic, it was because that ultrasonic adjusted and regrouped sludge structure, and the hydration water in the sludge was released. [Conclusion] The study could provide certain theoretical foundation for the industrial application of ultrasonic.
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