This paper analysed geometries and flows in household slow sand filters (HSSFs) through computational fluid dynamics (CFD) to evaluate the hydrodynamics of filters. Four HSSFs in full scale were studied with a capacity to produce 48 L.d^-1 each with diameters of 190 mm and 250 mm and with a filter medium depth of 0.5 m. The hydrodynamics of the four mathematical models of the HSSFs was validated using the experimental residence time distribution (RTD). The Kruskal Wallis non-parametric test indicates that the results of the experimental RTDs and the simulated RTDs did not show significant differences, therefore the mathematical models represent the physical models, which requires a detailed 3D analysis of the flow in the filters. The results showed that the HSSFs have a flow close to plug flow reactor. Internal recirculation zones were not found, nor short-circuit ones; however, dead zones were verified at the base of the filter with volumes below 3% when compared to the total volume of the filtering and draining layers, not necessary to make changes in geometry. The results of the computational simulation showed that the continuous filters had a smaller velocity variation and the filters with smaller diameter presented a reduction in dead zones when compared to the filters with larger diameters operated in the same flow regime. The study focused on the hydraulic aspects of HSSFs, but it is noteworthy that the choice of the type of operation to be adopted by families that use this type of treatment depends on studies that assess the efficiency of water treatment filters that were not considered in this work.

本文通过计算流体动力学 (CFD) 分析了家用慢砂过滤器 (HSSF) 的几何形状和流量，以评估过滤器的流体动力学。研究了四个全尺寸 HSSF，其生产能力为 48 Ld ^-1直径分别为 190 mm 和 250 mm，过滤介质深度为 0.5 m。使用实验停留时间分布 (RTD) 验证了 HSSF 的四个数学模型的流体动力学。Kruskal Wallis 非参数检验表明，实验 RTD 和模拟 RTD 的结果没有显着差异，因此数学模型代表物理模型，这需要对过滤器中的流动进行详细的 3D 分析。结果表明HSSFs具有接近活塞流反应器的流动。没有发现内部回流区，也没有发现短路区；然而，与过滤层和排水层的总体积相比，过滤器底部的死区体积低于 3%，无需更改几何形状。计算模拟结果表明，连续过滤器具有较小的速度变化，与在相同流态下运行的较大直径过滤器相比，较小直径过滤器的死区减少。该研究侧重于 HSSF 的水力方面，但值得注意的是，使用这种处理方式的家庭所采用的操作类型的选择取决于评估水处理过滤器效率的研究，这些研究未在此考虑工作。