The City of Fort Worth is expanding the Rolling Hills Water Treatment Plant from 160 mgd to 200 mgd capacity. As part of this expansion project, a 200-mgd raw water ozonation facility has been constructed and put into operation. Ozonation was selected to meet current and future regulatory requirements, reduce tastes and odors, and improve overall treated water quality. This paper presents a case study for implementing a new ozonation facility into an existing large-scale plant and addressing the issues and challenges with such a facility. Includes 3 references, tables, figures.