Severn Trent Water are currently undertaking an extensive capital programme to enhance water treatment facilities at many of its major works. This paper describes the various aspects of the Birmingham Water Treatment Plant Redevelopment Strategy with specific emphasis on the factors that lead to the selection of dissolved air flotation (DAF) as a main stage of clarification and subsequent construction of the largest DAF plant in the world. The design, construction and operation of the plant are reviewed with particular attention to water quality and the use of carbon dioxide within the process stream to produce a stable treated water.