What is DAF?

DAF stands for Dissolved Air Flotation, a water treatment process that clarifies wastewater by removing suspended matter such as oils, solids, and other contaminants. The process involves dissolving air in the water or wastewater under pressure and then releasing the air at atmospheric pressure in a flotation tank or basin. The released air forms tiny bubbles that adhere to the suspended matter, causing it to float to the surface of the water, where it can be removed by a skimming device.

Key Components and Steps of DAF

Pre-treatment: Wastewater is often pre-treated to adjust pH levels and add coagulants or flocculants that help bind the suspended particles together.
Air Dissolution: Air is dissolved in the wastewater under pressure in a saturation tank.
Release and Flotation: The pressurized water is released into the flotation tank. As the pressure is released, the dissolved air comes out of solution and forms microbubbles.
Attachment: The microbubbles attach to the suspended particles, causing them to rise to the surface.
Skimming: A skimming device removes the floated material from the surface of the water.
Discharge: The treated water, now clarified, is discharged from the bottom of the tank.

Applications of DAF

Municipal wastewater treatment: To remove solids, oils, and grease.
Industrial wastewater treatment: Used in industries such as food and beverage, pulp and paper, oil and gas, and chemical processing.
Pretreatment systems: Before biological treatment processes or membrane filtration.
Sludge thickening: To concentrate sludge and reduce its volume.

DAF is valued for its ability to handle a wide range of wastewater types and its effectiveness in removing fine particles and oils that are difficult to separate using other methods.