College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China.
J Environ Sci (China). 2011;23(8):1266-73. doi: 10.1016/s1001-0742(10)60566-9.
The changes in the physical characteristics of unconditioned and conditioned anaerobic digested sludge (ADS) biosolids, such as capillary suction time (CST), yield stress, average size and fractal dimensions, were investigated through a CST test, transient and dynamic rheological test and image analysis. The results showed that the optimum polymer dose range was observed when CST or its reciprocal value was employed as an indicator. There were good correlations between the yield stresses determined from both a controlled shear stress test and a strain amplitude sweep test. The yield stress and storage modulus (G') increased as the polymer dose increased in most cases. A frequency sweep test revealed that polymer conditioning could extend the frequency sweep ranges for their elastic behaviors over viscous behaviors as well as the gel-like structure in the linear viscoelastic range. These results implied that more deformation energy was stored in this rigid structure, and that elastic behavior became increasingly dominant with the addition of the polymer in most cases. In addition, both the average sizes and two-dimensional fractal dimensions for conditioned ADS biosolids presented a similar up-climax-down variation trend as the polymer doses increased, whereas the critical polymer doses at the highest average sizes or two-dimensional fractal dimensions, were different. Correlation analysis revealed that the conditioned ADS dewaterability was not correlated with the yield stresses, while the average sizes or the two-dimensional fractal dimensions for conditioned ADS biosolids could be taken as the indication parameters for ADS dewaterability.
通过 CST 测试、瞬态和动态流变测试以及图像分析，研究了未驯化和驯化厌氧消化污泥（ADS）生物固体的物理特性变化，如毛细吸水时间（CST）、屈服应力、平均粒径和分形维数。结果表明，当 CST 或其倒数用作指标时，观察到最佳的聚合物剂量范围。从受控剪切应力测试和应变幅度扫描测试确定的屈服应力之间存在良好的相关性。在大多数情况下，随着聚合物剂量的增加，屈服应力和储能模量（G'）增加。频率扫描测试表明，聚合物调理可以扩展其弹性行为相对于粘性行为以及在线性粘弹性范围内的凝胶状结构的频率扫描范围。这些结果表明，在大多数情况下，更多的变形能储存在这种刚性结构中，并且随着聚合物的添加，弹性行为变得越来越占主导地位。此外，随着聚合物剂量的增加，驯化 ADS 生物固体的平均粒径和二维分形维数均呈现出相似的上升-下降变化趋势，而在最高平均粒径或二维分形维数处的临界聚合物剂量则不同。相关分析表明，驯化 ADS 的脱水性能与屈服应力无关，而驯化 ADS 生物固体的平均粒径或二维分形维数可用作 ADS 脱水性能的指示参数。
