A Note on Baffle Orientation in Long Ponds

Abstract

This paper assesses the general idea of implementing transversal baffles to improve hydraulic efficiency of rectangular ponds used in water and wastewater treatment processes. The paper concentrates on long ponds with the length-to-width ratio of 4:1. Three different scenarios of plain (baffle-less) pond and ponds with four transversal and two longitudinal baffles were considered. A two dimensional Computational Fluid Dynamics (CFD) conservative tracer study was performed. Results showed that the longitudinal layout of the baffles yielded to a hydraulic regime closer to the plug-flow condition, while application of limited number of transverse baffles in long ponds showed an adverse effect on the overall hydraulic performance. Such baffles layout yielded to increased dispersion, as well as comparable dead zones in comparison with the plain pond. A three dimensional analysis was also conducted to evaluate the effect of volumetric dispersion, which yielded to the same results. Possible reasons for this phenomenon were discussed. Results suggest that application of limited number of transverse baffles in long ponds needs extra consideration.

Keywords: CFD, longitudinal baffles, long ponds, transverse baffles, water and wastewater