Wett B, Demattio M, Becker W
Institute of Environmental Engineering, University of Innsbruck Technikerstr. 13, A-6020 Innsbruck, Austria.
Water Sci Technol. 2005;51(10):65-73.
The purpose of this paper is an experimental and model assisted investigation of the capabilities of a dewatering system for sewage sludge for decentralised sites. Laboratory and field tests are performed with different initial conditions and the influences of filter medium, initial height, initial total suspended solids, temperature and relative humidity are discussed. The experimental work shows the feasibility of geotextile media for dewatering high water content sewage sludge and that the textile structure is of secondary importance. The specific filter resistance of the sludge cake is found to be the most significant factor in dewatering applications. The mathematical description of the dewatering process is based on the superposition of two models, the Conventional Filtration Theory for the filtration phase and the BT-model for the drying phase. Feasibility and limits of the theoretical approach are evaluated by means of a comparison between measurements and simulated data of cyclic reloading tests. It is found that a better filtration efficiency is achieved at higher TSS and at lower initial height of the slurry layer. Due to the viscosity decrease, a higher temperature enhances not only evaporation, but also filtration rate.
本文的目的是对分散式场地污水污泥脱水系统的性能进行实验和模型辅助研究。在不同初始条件下进行了实验室和现场测试，并讨论了过滤介质、初始高度、初始总悬浮固体、温度和相对湿度的影响。实验工作表明了土工织物介质用于脱水高含水量污水污泥的可行性，且织物结构的重要性次之。发现污泥饼的比过滤阻力是脱水应用中最重要的因素。脱水过程的数学描述基于两个模型的叠加，即过滤阶段的传统过滤理论和干燥阶段的BT模型。通过循环加载试验的测量数据与模拟数据的比较，评估了理论方法的可行性和局限性。结果发现，在较高的总悬浮固体含量和较低的浆料层初始高度下可实现更高的过滤效率。由于粘度降低，较高的温度不仅提高了蒸发速率，还提高了过滤速率。
