DAF — Dissolved Air Flotation

Dissolved Air Flotation (DAF) is a water treatment process that clarifies wastewaters (or other waters) by the removal of suspended matter such as oil or solids.

The removal is achieved by dissolving air in the water or wastewater under pressure and then releasing the air at atmospheric pressure in a flotation tank basin.

The released air forms tiny bubbles which adhere to the suspended matter causing the suspended matter to float to the surface of the water where this layer of sludge is removed by a skimming device. Flocculants and coagulants are often added to improve the performance of the unit.

Dissolved Air Flotation performance depends on the air to solids ratio, and this will vary with different types of suspension as the flotation process is dependent on the surface area of the materials.