MODELING SEDIMENT-INDUCED DENSITY CURRENTS IN SEDIMENTATION BASINS

The mathematical model introduced here allows one to predict, by direct computation, the behavior of the bottom current and the surface return flow, and simultaneously to determine their distributional effects on the sedimentation process itself. The model consists of conservation equations for fluid mass and momentum and sediment volume, supplemented by a modified form of the k- epsilon turbulence closure model. This paper emphasizes the description of features of the model and the presentation of results for a set of flows that may occur in a typical circular secondary clarifier. These results include the flow pattern, concentration distribution of sediment, the percentage of solids removal, and some examination of turbulence quantities in the basin. Some model sensitivity studies are reported.