Examining the Effects of Longitudinal Inclined Plates and Perforated Inlet Baffle on the Settling Efficiency of a Rectangular Sedimentation Tank: A Computational Fluid Dynamics Study

The effects of longitudinal inclined plates and perforated inlet baffle on the settling efficiency and the overall hydrodynamics of a rectangular sedimentation tank are investigated using computational fluid dynamics. Five new cases of modified geometry have been thoroughly analyzed for this study. To simulate the multiphase flow, the Euler-Lagrange method is adopted by using the Discrete Phase Model. Experimentally obtained particle size distribution data of a potable water treatment plant and an industrial wastewater treatment are used to examine the effectiveness of the modifications in improving the settling efficiency. The longitudinal inclined plates are found to be highly effective in increasing the settling efficiency by increasing the settleable area, while the perforated baffle is found to be useful in dissipating the kinetic energy from the influent and helps in achieving plug-flow conditions in the sedimentation tank. It was also found that the controlled recirculation currents may be beneficial for settling fine particles.