Domestic wastewater ozonation:: A kinetic model approach

Film theory has been applied to model the ozonation kinetics of a domestic wastewater. The model has been applied to the ozonation in a bubble column where gas and wastewater were fed countercurrently. Because the wastewater composition was not explicitly known, an index of its pollution (i.e., COD) has been taken as the parameter to study the chemical reaction kinetics. The kinetic model considers the fluid dynamics of liquid and gas phases flowing through the ozonation contactor. The axial dispersion and the tanks in series models for non-ideal flow were used for this objective. Additionally, ozone mass transfer parameters were evaluated from experimental data. The kinetic model predicts reasonably well the remaining COD at the given experimental conditions. However, deviations were observed between the experimental and calculated dosage of ozone, probably due to contributions of free radical reactions, which have not been considered in the proposed hypothesis.