The use of selective and direct DAF for removal of particulate contaminants in drinking water treatment

Abstract

Cationic polymers were found to coat bubbles resulting in charge reversal and increasingly positive EPM. Batch bench-scale dissolved air flotation (DAF) studies show promising benefits from the addition of cationic or non-ionic polymers to the saturated recycle line of conventional DAF. In cases where low turbidity, low color waters are being treated, direct DAF compared well with conventional DAF. Polymer addition improved the percentage solids of the float. Anionic polymers were not found to be effective. Further research at the pilot and full-scale is needed to verify these findings.