Induced Gas Flotation (IGF) 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 injecting gas bubbles into the liquid in a flotation tank or basin. The small bubbles 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.
Induced Gas Flotation is very widely used in treating the industrial wastewater effluents from oil refineries, chemical plants and similar industrial facilities.
Induced Gas Flotation units in the oil industry do not use air as the flotation medium due to the explosion risk.
The feed water to the induced gas flotation float tank is often dosed with a coagulant to flocculate the suspended matter.
The bubbles may be generated by an impeller, eductors or a sparger. The bubbles adhere to the suspended matter, causing the suspended matter to float to the surface and form a froth layer which is then removed by a skimmer.
The froth-free water exits the float tank as the clarified effluent from unit. Some induced gas flotation unit designs utilize parallel plate packing material to provide more separation surface and therefore to enhance the separation efficiency of the unit.