COMPUTER SIMULATION OF HYDRODYNAMIC BEHAVIOR IN OPTIONAL PONDS WITH BAFFLING

Abstract

Wastewater facultative ponds are used extensively to provide wastewater treatment in Brazil. While understanding the hydraulics of facultative ponds is critical to their optimization, there is a poor understanding of the behavior of the flow that exists within them. The objective of this study is to apply Computational Fluid Dynamics (CFD) modeling on waste stabilization ponds with many configurations including baffling. From the comparison of the results the following conclusions were drawn: (1) the flow for the geometry without baffles was characterized by high levels of short-circuiting and large re-circulation regions; (2) the use of baffles creates flow fields in the tanks which reduce short-circuiting and the re-circulating regions. Particularly, the results show that ponds with two longitudinal baffles are more effective in terms of hydrodynamic behavior because the use of baffles creates flow fields with significant volumes of "plug flow" and the regions with very low velocities are significantly diminished. Keywords: facultative ponds; baffling; hydrodynamic behavior; hydraulics