This article identifies process parameters, develops a conceptual model for estimating organics removal and ozone adsorption efficiencies in bubble reactors, and analyzes the model for sensitivity to the process parameters. According to the model, the efficiencies of removal of organic contaminants in ozone reactors are determined mainly by the reactivity and volatility of the contaminants. The chemical composition of the water, the mass transfer characteristics of the reactor, and operational parameters (flow rates of the gas and water, concentration of ozone in the applied gas stream, and detention time) are identified as process parameters that control the performance of the reactors. Once the methodology has been developed, the model can be used to evaluate different operational alternatives for optimum performance of ozone reactors and to make performance and cost comparisons between ozonation and other processes, such as activated carbon adsorption and air stripping. Includes 13 references, table, figures.