The volumetric mass transfer coefficient (K_La) for ozone was determined for various operational conditions in a novel ozonation-ceramic membrane system. Four operational parameters, water flow rate, gas flow rate, inlet gaseous ozone concentration and water temperature were considered. K_La values were higher at high water flow rates, because of the increased turbulence created under high flow conditions. K_La values were higher at high gas flow rates, because of the greater interfacial surface area of the bubbles at high gas flow and the increased turbulence created the air bubbles. Initially the K_La value found for the system increased with the ozone gas concentration, however, at the highest ozone gas concentration studied the K_La value decreased, possibly because the diffusion of gaseous ozone becomes rate limiting under these conditions. The water temperature had little effect on the K_La value over the temperature range from 10 °C to 30 °C. A mathematical model was developed to describe the concentration profiles of dissolved ozone in the ozonation-membrane system. Over a wide range of operating conditions there was a good agreement between the predicted and experimental data.
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