AWWA ACE63169

This slide presentation outlines a pilot study for dissolved air flotation (DAF) pretreatment at the City of Boulder, Colorado's Reservoir plant which resulted in full scale installation. Objectives of the piloting process were: to achieve better or similar raw water quality; and, to determine the best technology based on operator attention, chemical manipulation, sensitivity to flow variation and turbidity spikes, and start up to equilibrium. Piloting approach criteria outlined in the presentation included: location of Betasso Water Treatment Plant in the foothills above Boulder, Colorado; proposed backwash recycle; process piping; instrumentation/operation; ballasted sand pilot; DAF pilot; Lamella Plate Settler pilot; and pilot installation. Pilot results included: influence of chemicals; water quality performance; and, process differences. Based on pilot results, DAF was chosen. Full scale DAF performance is outlined, focusing on: operation strategy; performance based on 5 years of data (Oct 2001 to Feb 2006); and, operational feedback. Full sale DAF operation impacts, full scale general operator observations, and success and recommendations are outlined. Includes tables, figures.