微波/超声波对污泥粒度与水分的影响

脱水是污泥处理的重要工艺，预处理技术可以改变污泥脱水特性，促使污泥含水率的降低。在总结国内外污泥脱水特性表征的基础上，对超声、微波和超声微波组合方法处理后的污泥进行实验，分析在不同的条件下，污泥的毛细吸水时间（capillary suction time，CST）、粒度分布、水分的变化情况，并根据差示扫描量热仪（differential scanning calorimetry，DSC）测试结果计算出结合水的含量。研究结果表明：在微波作用时间为180 s时效果最好，污泥的CST为5.8 s，d50为5.423 μm；超声作用30 s时效果最好，污泥的CST为12.1 s，d50为4.509 μm；在超声与微波组合作用下微波时间为60 s、超声时间为30 s时，污泥的CST为12.8 s，d50为3.731 μm。在此3种作用条件下，DSC图谱中峰值出现较早，峰值处热流分别为3.428、4.343和4.268 W·g-1。分析结果表明，经预处理后的污泥脱水特性向着有益于脱水的方向改变，粒度分析与DSC能够表征污泥含水率的变化情况。

Analysis of particle size distribution and water content on microwave/ultrasound pretreated sludge

Dewatering is a necessary process of sludge treatment and resource. Pretreatment technology can effectively improve the dewaterability of sludge and increase the water content. After summarization of the recent local and international sludge treatment technologies, we adopted the microwave, ultrasound, and microwave and ultrasound combination techniques to pretreat sludge, with different microwaving times, analyzed particle size distributions, and sludge water contents. The bound water content could be calculated from the measuring results. The results indicated that the pretreatment effect was satisfactory when the microwave time was 180 s, CST was 5.8 s, and d50 was 5.423 μm. When the ultrasound time was 30 s, the CST was 12.1 s, and d50 was 4.509 μm. After microwaving for 60 s and ultrasound for 30 s, in combination, the CST was 12.8 s and d50 was 3.731 μm. The research focused on DSC analysis of the sludge results, which showed a peak appearing earlier in these three conditions, with the heat flux rate being 3.428, 4.343, and 4.268 W·g-1, respectively. These data indicate that the pretreatment technology has a superior dehydration effect, and that analysis of the particle size distribution and DSC could characterize the water content changes.