Much research has been conducted to improve sludge dewaterability and reveal its dewatering process. However, to date, two key issues remain unsolved: (1) the difficulty of dewatering sludge and (2) why suitable chemical conditioning can improve sludge dewaterability. This study is focused on addressing these two problems using a rheological analysis. Flow and dynamic measurements were performed to investigate the rheological properties of three types of sludge samples (raw sludge, acid-conditioned sludge, and Fenton-conditioned sludge) with different dewatering performances and a total solid content (TS) range of 20–62 g/L (2–6.2 wt %). The measured data were fitted to predict the rheological behaviors of the sludge at moderate and high TS values (15–50 wt %). A horizontal analysis and comparison of the rheological characteristics of the sludge samples indicated that rheological properties of the sludge exhibited a strong dependence on the solids content of the raw and treated sludge. An increase in the solids content significantly strengthened the solid-like properties and increased the deformation resistance, causing the sludge to become more resistant to flow and resulting in lower flowability of the sludge system; this provided an explanation for the difficulty in sludge dewatering. A vertical comparison and analysis of the rheological behavior of the sludge samples addressed the second key issue and indicated that a suitable conditioning method such as acid and Fenton oxidation conditioning had positive effects on the evolution of the rheological parameters of the sludge; namely, the conditioning resulted in weaker viscoelastic properties and better flowability. These results provide insights into the fundamental mechanism of sludge dewatering through rheological analysis.

中文翻译：

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使用流变学分析法对废活性污泥脱水过程进行补充深度分析

为了改善污泥的脱水性并揭示其脱水过程，已经进行了许多研究。然而，迄今为止，仍未解决两个关键问题：（1）污泥脱水的难度；（2）为什么进行适当的化学处理可以改善污泥的脱水性。这项研究的重点是使用流变分析解决这两个问题。进行流量和动态测量以研究三种具有不同脱水性能和总固体含量（TS）范围为20–62 g的污泥（原始污泥，酸处理污泥和Fenton处理污泥）的流变特性。 / L（2–6.2重量％）。测得的数据适合于预测在中等和较高TS值（15-50 wt％）下污泥的流变行为。对污泥样品的流变特性进行的水平分析和比较表明，污泥的流变性质表现出对原始和处理后污泥固体含量的强烈依赖性。固含量的增加显着增强了固体状，并提高了抗变形性，使污泥变得更不易流动，并导致污泥系统的流动性降低。这为污泥脱水的困难提供了解释。垂直比较和分析污泥样品的流变行为解决了第二个关键问题，并表明合适的调节方法（如酸和Fenton氧化调节）对淤泥流变参数的演变具有积极影响；即 调节导致较弱的粘弹性和更好的流动性。这些结果通过流变分析提供了对污泥脱水的基本机理的见解。