School of Environmental Science and Engineering, Donghua University, Shanghai 201620, China.
J Environ Sci (China). 2011;23(5):875-80. doi: 10.1016/s1001-0742(10)60518-9.
Moisture distributions in municipal sewage sludge, printing and dyeing sludge and paper mill sludge were experimentally studied based on four different methods, i.e., drying test, thermogravimetric-differential thermal analysis (TG-DTA) test, thermogravimetric-differential scanning calorimetry (TG-DSC) test and water activity test. The results indicated that the moistures in the mechanically dewatered sludges were interstitial water, surface water and bound water. The interstitial water accounted for more than 50% wet basis (wb) of the total moisture content. The bond strength of sludge moisture increased with decreasing moisture content, especially when the moisture content was lower than 50% wb. Furthermore, the comparison among the four different testing methods was presented. The drying test was advantaged by its ability to quantify free water, interstitial water, surface water and bound water; while TG-DSC test, TG-DTA test and water activity test were capable of determining the bond strength of moisture in sludge. It was found that the results from TG-DSC and TG-DTA test are more persuasive than water activity test.
基于四种不同的方法，即干燥试验、热重-差示热分析（TG-DTA）试验、热重-差示扫描量热法（TG-DSC）试验和水活度试验，对城市污水污泥、印染污泥和造纸厂污泥中的水分分布进行了实验研究。结果表明，机械脱水污泥中的水分是间隙水、表面水和结合水。间隙水占总水分含量的 50%以上。随着水分含量的降低，污泥水分的结合强度增加，特别是当水分含量低于 50%wb 时。此外，还对四种不同测试方法进行了比较。干燥试验具有定量测定自由水、间隙水、表面水和结合水的能力；而 TG-DSC 试验、TG-DTA 试验和水活度试验能够测定污泥中水分的结合强度。研究发现，TG-DSC 和 TG-DTA 试验的结果比水活度试验更有说服力。
