Estimation of air concentration in dissolved air flotation (DAF) systems using a simple predictive tool

Dissolved air flotation (DAF) has been used for several decades in water treatment systems. It is a unit operation for the separation of solid and semisolid (floc) particles from a liquid phase that has been used for the clarification of potable water. The removal is achieved by dissolving air in the water or wastewater under pressure and then releasing the air at atmospheric pressure in a flotation tank or basin. The increased dissolved air concentration in water at elevated pressure is the fundamental principle that allows the formation of microbubbles. In this article a simple predictive tool is developed to estimate air saturated concentration in dissolved air flotation (DAF) systems. Estimations are found to be in excellent agreement with reported data in the literature with average absolute deviation being around 0.5%. The tool developed in this study can be of immense practical value for process engineers to have a quick check of air concentration in dissolved air flotation systems (DAF) at various conditions without opting for any experimental trials. In particular, water practitioners and process engineers would find the proposed approach to be user-friendly with transparent calculations involving no complex expressions. (C) 2012 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.