A Hybrid Approach for Increasing Baffling Factors in Contact Tanks

Abstract

A novel approach using a hybrid combination of internal baffles and industrial packing material is investigated in order to optimize the hydraulic residence time of a 1,500‐gal rectangular concrete tank. Hydraulic residence time, which is commonly classified using the baffling factor (BF), was determined from residence time distribution curves obtained using both computational fluid dynamics (CFD) simulations and physical tracer studies. CFD simulations were used to model two scenarios. The first scenario was a base system consisting of an unbaffled concrete tank, and the second scenario was a two‐baffle system. Computational simulation results were experimentally validated via tracer studies on a full‐scale prototype. Modifications to the two scenarios were then experimentally implemented by locally placing random packing material at regions of high velocity and flow separation. Associated results highlight that the hybrid combination of baffling and packing material yielded substantial gains in the BF over systems using only internal baffles or only inlet modification.