PRIMARY CFD SIMULATION FOR URBAN WASTEWATER TREATMENT WITH SECONDARY SEDIMENTATION TANK

摘要

The need to treat wastewater is a major concern for Chinese city. Secondary sedimentation tank is used widely in wastewater treatment. However, few literatures are about the flow in secondary sedimentation tank. Therefore, the flow dynamics in a secondary sedimentation tank is studied in this paper. The solid-liquid two-phase laminar flow in the tank is modeled with three-dimensional two-fluid model. By using CFD, the velocity profile and solid concentration distribution are given. The volume concentration of solid varies with the difference of the radial and axial distances. The contours of solid concentration are compared between the tanks with baffle and without baffle. These results provide useful information for the design of the tank.