DAF Technology


Wastewater is generated in each industry and each has unique treatment approaches. Before implementation of best technology for the treatment, considerable study must be done. Detailed potential scenarios for the treatment must be applied in order to minimize the cost for the treatment.

DAF systems are designed to remove suspended solids (TSS), biochemical oxygen demand (BOD5), and oils and greases (O&G) from a wastewater stream. Contaminants are removed through the use of a dissolved air-in-water solution produced by injecting air under pressure into a recycle stream of clarified DAF effluent. This recycle stream is then combined and mixed with incoming wastewater in an internal contact chamber where the dissolved air comes out of solution in the form of micron-sized bubbles that attach to the floccs. The bubbles and contaminants rise to the surface and form a floating layer of material that is removed by a spiral scoop.

Standard supply of the DAF system includes:

  • Construction in high quality stainless steel
  • Quality drive and pump components for long-term reliability
  • Multi-step quality control program
  • Complete start-up and training services
  • Process design assistance
  • Expert technical support before and after installation


Optionally supply of the DAF system includes:

  • Flotation cell with cover
  • Water quality sensors
  • Custom control systems  SCADA


DAF clarifiers are manufactured as round and rectangular tanks. For the round DAF clarifiers KROFTA is implementing ZERO VELOCITY principle. The rotation is synchronized so that the water in the tank achieves ZERO VELOCITY during flotation. This means that the efficiency of the flotation is greatly increased to near the maximum theoretical limits. In practical terms, this allows better clarification in smaller surface areas and in a much shallower tank. The open tank has an approximate depth of 460 mm. Water is processed from inlet to outlet in two to three minutes.

Dissolved air flotation technology compared to sedimentation clarification technology, is much more cost effective, lower engineering design costs, lower installation cost and overall more effective technology. DAF clarifiers are excellent for removing fine suspended solids and for cleaning up water clarity problems. Water after DAF clarifier is excellent for recycling or for discharging to the sewer system.