Retrofitting Media Filters with Immersed Ultrafiltration Membranes for Thornton, CO

Paper summarizes the largest retrofit of conventional granular media filters with low pressure membranes in the world. City of Thornton, CO, conducted pilot testing of five microfiltration MF) or ultrafiltration (MF) membrane systems for a retrofit of membranes into a conventional granular media surface water treatment plant. Subsequently a UF system was selected in a competitive bid for the retrofit of the Columbine Water Treatment Plant. The project increased the capacity of the Columbine WTP from 30 to 50 MGD.