Dissolved Air Flotation (DAF)


  • To eliminate tiny suspended solids
  • Under pressure, dissolved air being fed into wastewater
  • Then releasing air into float tank at atmospheric pressure
  • Resulting formation of air bubbles which stick to suspended solids
  • Floating bubbles will be removed by skimming devices
  • Reduced carbon footprint as chemicals are not involved to leave any trace

Compared to conventional grease arrestors, dissolved air floatation (DAF) tank is a much more effective device for the removal of oil and grease (OG), and fine suspended solids (SS) from the trade wastewater. In industries such as food manufacturing or related to periodic caustic discharges, pre-treatment procedure using DAF treatment method is proven to be the most adequate among other simple passive pre-treatment devices.

Micro fine air bubbles produced within the DAF chamber will conglomerate with the contaminants which are insoluble in water, and the combination will float to the surface, forming a sludge top layer. This layer will then be removed by a scrapping or skimming device, leaving the purified water to be discharged to the sewer or to enter a secondary treatment device.

It is optional to perform chemical dosing within the DAF vessel, depending on the nature of the wastewater. Some industry with heavy loads of contaminants might need addition of chemicals or polymers to improve the sedimentation or filterability of small particles.

One of the biggest advantage of using DAF tank is the flexibility of the design and to accommodate changes in source flow and loadings. The contaminant loadings and clients’ requirement determine the design. The size of a DAF can be designed based on the contaminant loads, hence this equipment would not take up too much space or use up unnecessary energy.