A Review of Vortex Grit Basin Design

摘要

Due to the challenges associated with sampling, and the low priority often bestowed on gritremoval, good data on grit removal in vortex grit basins is surprisingly rare. A review ofexperimental and full scale plant results, mathematical models and CFD model results wereundertaken with the goal of identifying a common separating mechanism in vortex grit basins.Finding such a mechanism would lead to a mathematical model or equation that can be used forthe design of vortex grit basins. Analysis of grit basins show that centrifugal forces are negligibleand intricate flow patterns do not exist. Sedimentation under the influence of gravity is the mainmechanism for grit removal in vortex grit basins. CFD modeling and the available data supportthis conclusion. Due to the high tangential velocity introduced by the influent flow, someallowance must be made to accommodate the resulting turbulence. Some mathematical modelsinclude such allowance, but the allowance has not been fully quantified. This is a keyrequirement for future research. CFD modeling is a tool that would allow for optimization of gritbasin design, particularly for those parameters, such as outlet configuration, that cannot be easilyincluded in a mathematical analysis. Suggestions are provided for other parameters that form partof vortex grit basin design.