Dissolved Air Flotation

What is it?

An Air flotation process is used when settlement alone would not address some parameters the client has a consent to discharge limit on.

Such as Fat, Oil and Grease which would naturally float. In turn, this would also address COD/BOD.

The aim of a DAF system is to get micro-bubbles trapped into the flocs generated during flocculation to raise their buoyancy making the flocs float at the surface.

The micro-bubbles are generated by surpressed (or compressed) air, mixed with clean water (also referred as “white water”) and injected into the raw flocculated effluent feed.

A scraper skims the surface of the floated effluent to collect the sludge which can then be dewatered on a filter press, screw press or centrifuge.

The rapidly settling particles, collected at the bottom of the DAF unit, can also transferred to the sludge dewatering station.

The clarified water is extracted from the DAF to be directed to the next process step or straight to discharge if the discharge limits allow us to.

DAF can typically be used as a preliminary physico-chemical treatment or as a final separation after an aerobic digestion.


Working in partnership with KWI , who has over 60 years experience installing DAF systems, we can provide you with a full turnkey solution to your effluent plant.


What makes


... by the range of industrial pollutions we can address : pH, heavy metals, cyanides, hexavalent chromium, BOD, "Hard" COD, Fat Oil & Grease, suspended solids, sulphates, phosphorous, nitrates, Ammonia, and anything you can think of to challenge us.

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... by picking the right technology for the right problem to provide the client with a guarantee of performance. Here are some of the processes we cover : Coagulation, Neutralisation, Flocculation, Oxidation, Reduction, Flotation, Settlement, Filter press, Screw press, Centrifuge, Ion exchange resin, Membranes technologies etc.

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Case studies

... Solving tricky problems for our customers is what gives us the edge and the enjoyment - We relish a challenge. Explore our case studies of previous projects

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