Investigating the Effect of Baffles on the Performance of Rectangular (Gould II Type) Settling Tanks Using a 3-D CFD Model

NYCDEP and City College of New York has developed a 3-D computer model to assess the performance and evaluate alternatives to improve the efficiency of rectangular Gould II type FSTs. Fluent was the base platform for the (CFD) model, for which sub-models of the SS settling characteristics as well as turbulence, flocculation and rheology were incorporated. The goal of this study was to use this tool to assess the internal behavior based on different baffle configurations at the inlet and especially for the 4H7V configuration. This configuration suggests at least from the hydrodynamic point of view a plug flow behavior immediately following the influent baffle. On the contrary the solids coupled model does not predict the same flow pattern due to the dominant density current effect. Following this outcome an additional in-tank baffle at a distance of 10m was added and its effect on the final clarifier performance was investigated.