A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science, School of Environment, Resources and Development

Thesis (M.Sc.) - Asian Institute of Technology, 1981

Because of its peculiar design, the rotating disc con tac tor is expected to be a different oxygen transfer system from other aeration devices. Evaluation of the oxygen supply of this particular system requires an insight into the mass transfer processes involved. In this thesis, a model of the oxygen transfer mechanism in rotating contactors is presented. Verification is made by comparison of experiment with theory on the results of rates of increase in oxygen concentrations of the bulk water. Accordingly, general equation which has been successfully employed for determining oxygen transfer coefficients is justified. This approach has not been followed by any previous workers before. The matching of aeration patterns from simulation and experiment validated the model, but, lower values of the transfer rates arise due to the neglection of surface aeration. Assumption of Cs as saturation concentration of oxygen in water in common practice is erroneous as applied to rotating contactors. Nevertheless, the error may be small and correlation of transfer coefficients so obtained with disc rotating velocity and radius is established.