AWWA JAW46261

A rational model that predicts the air transfer efficiency in the packing layer of dissolved air flotation saturators is described. The model is defined in terms of absolute air concentrations, assumes the Lewis-Whitman two-film theory, and uses the Onda correlations to estimate the mass transfer coefficient. A comprehensive method is proposed for experimentally determining the overall air transfer efficiency of an operating saturator. A series of experiments was performed to partition the overall transfer efficiency into the contributions of top and bottom end effects, of free fall of the water before it reaches the packing, and of the packing itself. The laboratory data show a close agreement of the theoretical model with the measured performance. The model is used to demonstrate the effects of the most important saturator design parameters on the concentration of precipitable air. Includes 11 references, tables, figures.