COMPARISON OF DISSOLVED AIR FLOTATION AND DIRECT-FILTRATION

Direct filtration with and without pre-ozone, and dissolved air flotation and filtration were evaluated for clarification of high quality reservoir water in Greenville, South Carolina, USA. Goals of the study included production of low turbidity filtered water and control of algae, iron and manganese, and disinfection byproduct precursors. The dissolved air flotation treatment train gave much longer filter runs than direct filtration, when both processes met the 0.10 NTU goal for filtered water quality. Use of pre-ozone was beneficial for direct filtration. Removal of TOC, DBP precursors, and iron and manganese were similar for both processes.