DAF – Dissolved Air Flotation

Category: Potable water

Flotation units with dissolved air allow to accelerate the separation of water and suspended solids. Compact and simple of use, they make it possible to recover at the same time floated and settling particles, and produce rejections with strong content of dry matter.


  • Simple to use
  • Compact construction
  • Capacity for treatment: 2 to 30 m3/h according to the models
  • Low cost of maintenance
  • Recovery of the solids on the surface and at the bottom of the flotation unit
  • Single system of drainage of the recovered solids

How it works

The aim of Physico Chemical treatment is to agglomerate the fine particles like certain soluble pollutants, which have difficulty in settling naturally or are in a dissolved state. These particles are coagulated into stable solids called “flocs” which allow the separator either settle them at the base of the DAF tank and remove them or alternatively float them to the surface where they are scraped off and removed from the liquid.

To reduce floor space required, Lamella packs are inserted into the tanks, and sludge is removed and dewatered further by belt filter presses. Pipe flocculators are mounted on the side of the tank or wall of the building. Whitewater is created and inserted at the inlet side, to ensure all light particles are floated to the surface. For FOG separation, DAFs are often used without the need for chemical addition.