The aqueous solution of a model textile reactive dye, C.I. Reactive Blue 15, was ozonated in a semi-batch reactor. Results of kinetic study showed that ozonation of the aqueous reactive dye was a pseudo-first-order reaction with respect to the dye. The apparent rate constant increased with both the applied ozone dose and temperature, but declined logarithmically with initial dye concentration. It was also found that the volumetric mass transfer coefficient of ozone increased linearly with initial dye concentration, applied ozone dose and temperature, respectively. The experimental data further indicated that ozonation effectively removed chemical oxygen demand (COD) and enhanced the biodegradability of the aqueous dye solutions. (C) 2007 Elsevier B.V. All rights reserved.