The Use of Rheology for Sludge Characterization
The Use of Rheology for Sludge Characterization
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DOI：
10.2166/wst.1982.0120
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发表时间：
1982-06
影响因子：
2.7
通讯作者：
H. W. Campbell;P. Crescuolo
中科院分区：
文献类型：
--
作者：
H. W. Campbell;P. Crescuolo
对各种厌氧消化的污水污泥进行了流变学测量，以评价流变学在描述化学调节对污泥物理特性的影响方面的潜在用途。该研究的目的是评估化学调节方法对流变学测量的影响；确定粘度计系统对仪器变量变化的响应；以及评估流变学和其他物理性质之间的相互关系。所有的流变学测量均使用同轴旋转粘度计。对各种测试程序的评估表明，添加化学调节剂的方法和旋转粘度计的加速率都可以显著改变流变图的形状。确定了一种建议的方法，并对选定的样品进行了一式三份的分析，以测试程序的重复性。现有的数学模型不能充分描述在污水污泥中观察到的各种流动行为模式。由于定义和计算的问题，屈服应力和表观粘度的概念也具有有限的价值。一个称为“瞬时粘度”的参数被定义为流动曲线的导数，它更适合于描述污泥的特性。探讨了化学条件、颗粒大小分布与外加剪切的关系。随着聚合物投加量的增加，污泥颗粒更容易发生剪切破碎。颗粒尺寸减小的程度是剪切速率和剪切保持时间的函数。
Rheological measurements were conducted on a variety of anaerobically digested sewage sludges to evaluate the potential use of rheology in describing the effects of chemical conditioning on the physical characteristics of sludges. The objectives of the study were to evaluate the influence of the method of chemical conditioning on rheological measurements; to determine the response of the viscometer system to changes in the instrument variables; and to evaluate interrelationships between rheology and other physical properties. All rheological measurements were made using a coaxial rotational viscometer. Evaluation of a variety of test procedures identified that both the method of adding chemical conditioners, and the acceleration rate of the rotational viscometer, could significantly alter the shape of the rheograms. A suggested methodology was identified and selected samples were analyzed in triplicate to test the reproducibility of the procedures. Existing mathematical models do not adequately describe the variety of flow behaviour patterns observed with sewage sludge. The concepts of yield stress and apparent viscosity also have limited value due to problems of definition and calculation. A parameter termed the “instantaneous viscosity”, defined as the derivative of the flow curve, is suggested as being more suitable for describing sludge behaviour. The relationships between chemical conditioning, particle size distribution and applied shear were explored. As polymer addition increased, the sludge particles became more susceptible to shear breakup. The extent of particle size reduction was a function of the rate of shear and the time during which the shear was maintained.