AWWA JAW64228

Full-scale biofiltration experiments demonstrated that good removal of biodegradable organic matter (BOM) following ozonation could be achieved without compromising particle removal. BOM removal by granular activated carbon (GAC) filter adsorbers and dual-media filters was measured using total organic carbon (TOC) and certain BOM components (carboxylic acids). The authors investigated how filter backwashing with water, water and air scour, and water and air scour at collapse-pulsing conditions affect filter biomass, BOM removal, and particle removal. At 21-24ºC, the media type did not affect BOM removal. At 1-3ºC, GAC provided substantially better removal of oxalate and TOC than did anthracite. For both media types, cold water oxalate removals were significantly impaired, compared with those achieved in warm waters. BOM removal was more resilient than particle removal to changes in backwash protocol. Phospholipid biomass concentration was not directly related to BOM removal by filters. Includes 35 references, tables, figures.