The Effect of Ozone Gas-Liquid Contacting Conditions in a Static Mixer on Microorganism Reduction

Abstract

Abstract The effect of gas-liquid contacting conditions in a static mixer on ozone transfer efficiency and reduction of Bacillus subtilis spores was studied in an experimental ozone contactor. An empirical mathematical model was developed that related the transfer efficiency in the experimental system to the superficial liquid velocity in the mixer, the gas-liquid flow rate ratio and the height of the down-stream bubble column. Spore reduction was determined primarily by the dissolved ozone concentration-time (Cavgtm) product in the reactive flow segment and was independent of the gas-liquid contacting conditions in the static mixer. In an integrated ozone contacting system, the static mixer should be designed to maximize ozone mass transfer while the reactive flow segment should be designed for efficient microorganism reduction. Keywords: OzoneStatic MixersBacillus subtilis SporesMicroorganism ReductionTransfer EfficiencyHydrodynamicsMass Transfer