What Is a DAF (Dissolved Air Flotation) Unit and How Does It Work?

A DAF (Dissolved Air Flotation) unit is a treatment stage that removes oil, grease, suspended solids and flocculated pollutants by floating them to the surface with micro air bubbles dissolved into the water under pressure.

The principle is simple: part of the treated water is saturated with air in a pressurized tank; when released into the DAF basin the pressure drops and the dissolved air comes out as micron-sized bubbles. These bubbles attach to pollutant particles and lift them; the surface foam is removed by a skimmer.

Coagulation–flocculation is usually applied before DAF; chemically formed flocs float far more easily with the air bubbles. Together they achieve high suspended-solid and oil removal.

It is preferred for streams with high oil and suspended-solid loads — food and dairy, textile, paint, refinery and slaughterhouse effluents. Its compact design handles high flows in a small footprint.

At Argon we manufacture DAF units with stainless-steel bodies, sized to the plant's flow and pollution load, and offer them as an integrated solution together with the coagulation unit.