Dissolved Air Flotation

Dissolved air flotation (DAF) is a physical/chemical waste water treatment process that clarifies waste waters by the removal of suspended solids along oil grease. 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 or 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 it may then be removed by a skimming device. Proper micro-bubble generation and flotation vessel design is key to the performance of a Dissolved Air Flotation unit. Along with the actual equipment design, the chemical program prescribed is very important to the success of the treatment system.

 

DAF units are very widely used in treating the industrial wastewater effluents from poultry and beef processing facilities, industrial laundries, food processing facilities, metal finishing, oil refineries, petrochemical and chemical plants, natural gas processing plants, paper mills, general water treatment and similar industrial facilities. A very similar process known as induced gas flotation is also used for wastewater treatment. Froth flotation is commonly used in the processing of mineral ores. In the oil industry, dissolved gas flotation (DGF) units do not use air as the flotation medium due to the explosion risk. Natural gas is used instead to create the bubbles.