Cavitation air flotation (CAF) system for wastewater treatment

We design, manufacture and install cavitation air flotation systems, also known as CAF systems, for industrial wastewater treatment. This is a highly effective wastewater clarification technology, whose operating principle is based on the injection of microbubbles directly into the wastewater without the need for an air flow.

CAF flotation equipment

Our cavitation air flotation system removes suspended solids, oils, grease and colloids from wastewater.

They have a compact and functional design, and are easy to install, operate and maintain, since they do not require air compressors, pumps or pressure tanks for wastewater treatment.

The equipment is rectangular in design and generally occupies little space, so there are usually no problems related to its location at the time of installation.

CAF flotation systems are generally applied as pre-treatments, although we have also carried out installations in which the CAF equipment has acted as a secondary clarification treatment, after a biological process, or as a tertiary treatment in a process that requires a final clarification.

The cavitation air flotation system injects micro bubbles into the wastewater inside the equipment, without the need for prior dissolution of air in the wastewater stream. These microbubbles, once introduced into the aqueous medium, allow the flotation of floatable particles and the sedimentation of solids in the same equipment.

Air is drawn in from outside by specially designed aeration equipment and is introduced pressurized into the equipment where, in contact with the wastewater, micro air bubbles are generated. Suspended solids adhere to the micro bubbles and are floated to the surface where a skimmer system sweeps solids, oils and grease from the surface of the wastewater.

The solids that have sedimented, due to their greater weight, are collected at the bottom of the equipment.

Both floated and settled sludge are directed to a sludge container.

Part of the clarified water is recirculated inside the equipment, thus avoiding the formation of sediments on the equipment surfaces.

Main components of the CAF system

  • Flotation chamber: The interior of the CAF equipment houses a volume of wastewater into which air is injected by blowers. In this chamber micro bubbles are generated and the effect of adherence and flotation of solids takes place.
  • Floated solids skimmer: It is a system of metal plates dragged by a simple and automatic chain mechanism. It drags the sludge made up of floated solids, oils, grease, etc., removing them from the surface of the clarified water.
  • Aeration system: The Aeration System of our CAFs is simple and robust, consisting of an air suction pump and an injector with blower that introduces the air sucked into the chamber of the CAF equipment.

Cavitation air flotation applications

Clarification using CAF systems can be applied in a wide variety of processes and industries:

  • In pretreatment processes, such as primary clarification, generally preceded by a physical-chemical coagulation-flocculation process.
  • As secondary clarification after biological treatment.
  • It is also applied in tertiary treatments, as a final clarification process.

They are adaptable and designed for capacities from 3 m3/h to large capacities of 250 m3/h. CAF technology is a highly efficient process in wastewater from all types of industries:

  • Food processors
  • Slaughterhouses
  • Meat and canneries
  • Chemicals and pharmaceuticals
  • Dairy
  • Production of sugar-sweetened beverages and juices
  • Cosmetics
  • Garbage cans
  • Tanneries
  • Leachate treatment
  • Oil companies
  • Fragrances and essential oils
  • Biodiesel and biomethane
  • Urban wastewater treatment plants


Air cavitation flotation equipment allows the separation of suspended solids, oils, grease and colloids, in addition to considerably reducing the organic load, producing a very high quality clarified product that in most cases complies with the limits for discharge to the local sewage system.

Estimated reduction yields obtained with our CAF system within a complete physicochemical process designed by Sigmadaf:

Total suspended solids
Oils and fats

Advantages of our CAF flotation equipment

Water clarification using an air cavitation flotation system has a number of advantages that make it a very attractive option for the treatment of industrial effluents:

  • Simple installation and operation
  • Fast start-up
  • Compact design
  • Manufactured in high strength and robustness materials: AISI304 or AISI316
  • Allows to treat flow rates from 3 to 250 m3/h
  • No civil works required
  • Minimal maintenance requirements: the recirculation system allows self-cleaning of the equipment.
  • The equipment is custom designed according to the flow rate and solids load.

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