text: The feed water to the IGF float tank is often (but not always) dosed with a coagulant (such as ferric chloride or aluminum sulfate) 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 the IGF unit.
  Some IGF unit designs utilize parallel plate packing material to provide more separation surface and therefore to enhance the separation efficiency of the unit.