Numerical Investigation of baffle effect on sedimentation anf flow field in sedimentation tank

Sedimentation by gravity is a common, highly applicable separation method for the suspended solid particles of water and wastewater. Sedimentation basin is an important component of every water treatment process. Due to high maintenance costs of these basins, up to about 30% of all costs in a water treatment plant, optimum performance of settling basin is very significant. In order to improve the efficiency of the basin, engineers have proposed various methods, among which, “changing the geometry along with installation of baffle in the basin” is economic and has attracted the attention of researchers. In the present paper, numerical simulation was made by using Flow3D software and RNG k-ε turbulence model for a flow consisting of settlement particles in the rectangular settlement basin by a finite volume method (FVM). This study aims at numerical simulation of the hydraulic flow in settling basins with various baffle configurations, and finally, obtaining the best geometry for the baffle. Considering the relative consistency of the numerical model results and the experimental data, the numerical simulation results were validated using the Flow3D model. The results showed that the flow in the settling basin is severely affected by the baffle. According to the studied models, it is clear that the baffles installed with lower height and closer to the basin inlet and baffles with high height and far away from the basin inlet have the most effective case on the settlement efficiency.