DAF (Dissolved Air Flotation)

DAF is a process for the removal of fine suspended material from an aqueous suspension.
DAF provide the needed energy for effective flotation in the form of extremely fine air bubbles which become attached to suspended material to be removed.
The attraction between the air bubbles and particles is a result of absorption forces that are a function of the characteristic of the particle surface, or physical entrapment in the particle.
This attachment of bubbles to the particle “reducing” the increase the effectiveness of the dissolved air flotation process.
The most reliable and positive producing bubbles of the proper size to dissolve air into water under pressure and then reduce the pressure of the solution.
As the pressure is reduced, the air comes out of solution in the form of micro-bubble.
The flotation process includes saturation with air, pumped through the relevant pump at pressure of 4-5 bar into part of the water previously treated.
The water air-mix is then piped at atmospheric pressure into the final part of the flocculation reactor with the water to purify.
In the processing zone of the flotation unit, for the brusque pressure drop, tiny air bubbles are instantaneously formed and slowly rise, taking the suspended parts with them, along with the flocculant reagent flakes.
Air and solids gather on the surface in the form of dense foam, which is removed with a scraper.
A lamellar structure, installed immediately under the surface of floctation unit, favors the separation of the flocculate, drastically reducing the density of the effluent water.
The sewage is piped from the lower part of the flotation unit to spillway.
The lamellar type separation system makes it possible to use a high specific flow, while maintaining a high separation performance and therefore the dimension of the plant will be very compact.


  • smaller plants of the common clarifies
  • retention time of water equal to 30 min
  • reducing the use of the chemicals
  • mud extracted exceeds 4-5%
  • excellent flotation slurry
  • low energy consumption
  • reduction of fat present in the water