Dissolved Air Flotation (DAF)
Dissolved Air Flotation (DAF) Unit, 4–300 m³/h
- Capacity
- 4–300 m³/h
- Material
- Carbon Steel/Stainless steel
6 models · Air Flotation (DAF)
Dissolved Air Flotation
Dissolved air flotation (DAF) is a clarification process that uses fine air bubbles to float suspended solids, oil, grease and fats to the surface, where they are skimmed off. It is widely used as pretreatment or primary treatment in food processing, slaughterhouses, dairies, paper mills, refineries and textile plants.
Air Flotation (DAF): available models
Dissolved Air Flotation (DAF)
Horizontal-Flow DAF for Paper Mill Wastewater
- Capacity
- 1–100 m³/h
- Power
- 15 kW, 25 kW
Dissolved Air Flotation (DAF)
Compact Ionized DAF Unit, 5 m³/h
- Power
- 3 kW
- Type
- Dissolved Air Flotation (DAF)
Cavitation Air Flotation (CAF)
Cavitation Air Flotation (CAF) Unit, 5–500 m³/h
- Capacity
- 5–500 m³/h
- Power
- 2 kW, 3 kW
Shallow Air Flotation
Shallow Air Flotation Unit
- Capacity
- Sized to project
- Material
- Carbon Steel with Anti-corrosion, Stainless Steel 304
Cavitation Air Flotation (CAF)
Cavitation Aerator / Micro-Nano Bubble Generator
- Power
- 1 kW, 2 kW, 3 kW
- Type
- Cavitation Air Flotation (CAF)
How it works
How dissolved air flotation work
Wastewater is usually dosed with a coagulant and flocculant to form larger flocs. A portion of clarified effluent is recycled, pressurized and saturated with air in a saturation vessel. When this recycle stream is released into the flotation tank at atmospheric pressure, the dissolved air comes out of solution as microscopic bubbles. The bubbles attach to the flocs and oil droplets, lowering their density so they rise to form a float layer. A surface skimmer removes this sludge to a collection hopper, while clarified water exits from below. Cavitation air flotation generates bubbles mechanically, and shallow air flotation uses a shallow, rotating tank design.
Selection guide
How to choose the right model
- 01
Flow rate and hydraulic loading
Size the unit on design flow, including any recycle stream, and on accepted surface loading rates for the application.
- 02
Solids and oil loading
High concentrations of suspended solids, fats or emulsified oil affect tank area, skimmer capacity and chemical demand.
- 03
Chemical conditioning
Most DAF applications need coagulant and polymer dosing. Jar testing on representative wastewater helps confirm chemical choice and dose.
- 04
Type of flotation unit
Conventional DAF suits a wide range of duties, cavitation units offer simpler bubble generation, and shallow flotation saves height and footprint for larger flows.
- 05
Materials of construction
Choose carbon steel with protective coating or stainless steel based on wastewater corrosivity, temperature and site requirements.
Typical applications
- Food and beverage processing
- Slaughterhouses and meat processing
- Dairy and edible oil plants
- Pulp and paper mills
- Petrochemical and refinery wastewater
- Textile and dyeing effluent
- Pretreatment before biological treatment
Learn more
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- Capacity
- 100–1,000 m³/day
- Process
- Drum screen + DAF + screw press
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FAQ
Dissolved Air Flotation: FAQ
What does a DAF system remove?
DAF removes suspended solids, fats, oil and grease, and with chemical conditioning it can also reduce colloidal material and part of the associated COD and phosphorus.
Do DAF systems need chemicals?
Most applications use a coagulant and a polymer flocculant to form flocs that bubbles can lift. Some streams with free oil may float with little or no chemical addition.
What is the difference between DAF and cavitation air flotation?
DAF dissolves air into a pressurized recycle stream and releases it as micro-bubbles. Cavitation air flotation creates bubbles mechanically with an aerator, which avoids a saturation vessel but typically produces larger bubbles.
Where should DAF be placed in a treatment plant?
DAF is usually placed after screening and equalization and before biological treatment. It protects downstream processes from fats, oils and solids shock loads.
Request a quotation
Need air flotation (daf) for your site?
Tell us the flow, the water or sludge you are treating and the result you need. A process engineer sizes the equipment and replies within one business day.