The Tampa Water Department (TWD) is in the construction phase of a large plantupgrade and expansion for the Hillsborough River Water Treatment Plant. Ozone was selected as the treatment improvement for the plant upgrade since ozone in conjunction with hydrogen peroxide has been reported to significantly reduce taste and odor compounds. This paper reports the results of pilot plant trials conducted to evaluate ozone and various proposed filter media configurations. To assess biological activity, heterotrophic plate count (HPC) analyseswere run on the filter effluent. Four trials were run; two target pH levels and two target peroxide levels were evaluated. Includes tables, figures.