Disinfection is a sanitary treatment present in both drinking water and wastewater treatment plants aimed at removing pathogenic microorganisms able to damage the human health. The focus of this study is to apply Computational Fluid Dynamics (CFD) to study and to improve the disinfection efficiency through the optimization of the hydrodynamics inside the disinfection tank. Numerous literature studies have shown that water flow inside traditional multichamber tanks is highly turbulent because of the development of large as well as small vortices in which flow velocity decreases or even vanishes (dead zones). These turbulent phenomena are responsible of an increase of the real residence time, compared to the theoretical one, causing poor disinfection and the development of unwanted by-products. In the present analysis, Large Eddy Simulation (LES) is used to simulate three-dimensional turbulent flow and disinfectant transport in different contact tanks using a structured finite-volume discretization. The results show how the baffles’ geometry, as well as the design of technical and construction details, influences the hydraulic retention time of the disinfectant, varying the disinfection efficiency. In particular, the creation of horizontal baffles inside the vertical baffle chambers reduces the free space and extends the flow path. This reduces both short circuits and recirculation zones bringing the flow closer to the ideal plug-flow condition.

消毒是饮用水和废水处理厂中都存在的一种卫生处理，旨在去除能够损害人类健康的病原微生物。这项研究的重点是应用计算流体动力学（CFD）来研究并通过优化消毒罐内的流体动力学来提高消毒效率。许多文献研究表明，传统的多室水箱内部的水流非常湍流，这是因为无论大小涡旋的发展，流速都会降低甚至消失（死区）。与理论上的相比，这些湍流现象导致实际停留时间的增加，从而导致消毒效果差和产生不需要的副产物。在目前的分析中，大涡模拟（LES）用于通过结构化有限体积离散化来模拟三维湍流和消毒剂在不同接触罐中的传输。结果表明，挡板的几何形状以及技术和结构细节的设计如何影响消毒剂的水力停留时间，从而改变消毒效率。特别地，在垂直挡板室内形成水平挡板减小了自由空间并延长了流动路径。这减少了短路和再循环区域，使流量更接近理想的塞流状态。以及技术和结构细节的设计会影响消毒剂的水力停留时间，从而改变消毒效率。特别地，在垂直挡板室内形成水平挡板减小了自由空间并延长了流动路径。这减少了短路和再循环区域，使流量更接近理想的塞流状态。以及技术和结构细节的设计会影响消毒剂的水力停留时间，从而改变消毒效率。特别地，在垂直挡板室内形成水平挡板减小了自由空间并延长了流动路径。这减少了短路和再循环区域，使流量更接近理想的塞流状态。