Modeling of Dissolved Ozone Concentration Profiles in Bubble Columns

Mathematical models previously employed to analyze concentration profiles of dissolved ozone in bubble‐column contactors often assumed either plug flow or complete mixing. In this paper a more realistic model, the axial dispersion model (ADM), was provided to integrate the nonideal mixing, mass‐transfer, and ozone‐decay process as a whole. The effects of various process parameters on the ozone profiles were analyzed numerically. It was found that a group of dimensionless quantities (PeL, Da, StG, and StL) is most convenient in describing the performance of ozone‐contacting systems. The different types of ozone contactors (countercurrent‐flow bubble columns, cocurrent‐flow bubble columns, and reactive contacting chambers) exhibited different patterns of concentration profile; as a result, different approaches are needed to relate their characteristic concentrations to readily observed measurements for predicting the disinfection efficiency. The applicability of the model is illustrated through the analysis of two separate sets of pilot‐scale data. Excellent conformity between the predicted profiles and observations was demonstrated.