Dissolved Air Flotation (DAF)


Each DAF is shipped prewired and ready for operation. Once power is connected to controls, all the customer has to do is bring feed and chemicals into the system and the separation process begins.


The unique Ellis pivoted Ferris wheel type skimmer minimizes solids accumulation and extends the lifespan of both moving chains and blades.


Unlike competing separation technologies, minor shifts in feed consistency will not upset the separation process within the DAF.

The Ellis Dissolved Air Flotation (DAF) system is a time-tested technology that has been installed in hundreds of facilities. Each DAF is shipped prewired and ready for operation. The low profile DAF is ideal for operations with clearance restrictions. Once power is connected to controls, all the customer has to do is bring feed and chemicals into the system and the separation process begins.

It very efficiently removes fats, oils, and greases (FOG) and suspended solids (TSS) from the wastewater as well as reducing the biological oxygen demand (BOD) and chemical oxygen demand (COD). FOG and TSS removal rates in excess of 95% are common. Some installations report a 99.9% reduction.

How it works


As shown above, the idea of Dissolved Air Flotation is as easy as 1, 2, 3.

1.  Preconditioned feed enters the DAF flowing towards the right (for reference). Most preconditioning is done to stabilize the feed and help solids stick together. This varies for every application. Please see Chemical Conditioning for more information on the various conditioning equipment Ellis has to offer that may improve DAF performance.  Prior to entering the DAF the feed is blended with a recycle line with clean effluent discharge that has been entrained with fine air bubbles. For more information on air distribution options please see Available Features and Options.

2.  Gravity will force any heavy solids that will naturally fall out of suspension to immediately drop towards the bottom of the DAF. The solids are discharged towards the left either with an installed auger or under natural hydraulic force of the liquid in the DAF.

3.  Solids that have coalesced with the air bubbles will float to the surface. These floating solids are scrapped towards the left side of the DAF and collected in a solids chamber. Any clean liquid effluent naturally flows to the opposite side of the DAF under a baffle and into a separate liquid effluent chamber.





DAF Sizing and General information

Model*Base LengthBase WidthUnit HeightUnit Inside WidthWater LevelEmpty Wt. [lbs.]Full Wt. [lbs.]
DAF-2013'-1 1/2"3'-1 1/4"7'-7 1/2"2'-6"5'-11"3,20011,200
DAF-3515'-1 1/2"4'-1 1/4"7'-9 1/2"3'-6"6'-1"4,80017,500
DAF-5517'-7 1/2"5'-1 1/4"7'-11 1/2"4'-6"6'-3"6,90028,600
DAF-8520'-7 1/2"6'-1 1/4"8'-5 1/2"5'-6"6'-9"9,80043,600
DAF-12025'-1 1/2"6'-7 1/4"8'-8 1/2"6'-0"7'-0"13,00068,200
DAF-15029' 1 1/2"7'-1 1/4"8'-11 1/2"6'-6"7'-3"15,00081,500
DAF-18029' 1 1/2"8'-1 1/4"9'-5 1/2"7'-6"7'-9"16,70099,600
DAF-20032'-1 1/2"8'-1 1/4"9'-5 1/2"7'-6"7'-9"18,000110,000
DAF-25035'-1 1/2"9'-1 1/4"9'-11 1/2"8'-6"8'-3"19,500141,000
DAF-33040'-1 1/2"10'-1 1/4"10'-5 1/2"9'-6"8'-9"23,600186,000
DAF-47555'-1 1/2"10'-1 1/4"10'-5 1/2"9'-6"8'-9"31,000255,000

Above information is approximate and subject to change.
*Model number designates floatable surface area (ft²), not hydraulic capacity


  • Algae Removal
  • Animal Food Production
  • Dairy & Mil Byproducts
  • Dyeing & Finishing Textiles
  • Energy Production Byproducts Treatment & Conditioning
  • Food Packaging & Processing Byproducts
  • Frozen Food Processing
  • Groundwater Remediation
  • Heavy Metal Removal
  • Industrial & Commercial Laundries
  • Industrial Floor Wash-down Solids Separation and Conditioning
  • Juice Separation and Conditioning
  • Meat Packing & Processing Byproducts
  • Oil & Petrochemical Production
  • Pre-biologic Pressing Treatment/Conditioning
  • Preparation of Parts for Painting
  • Pulp & Paper Production
  • Secondary Biological Solids Removal
  • Secondary Sludge Thickening (Industrial & Municipal)
  • Steel Mill Production
  • Storm Water Runoff
  • Vehicle & Fleet Washing



Materials of Construction Air Distribution Solids Discharge Auger Solids Float Skimming Intake & Discharge Pumping Controls Freeze Protection Covers & Hatches Effluent Chamber pH Adjustment Intake Heat Conditioning OSHA Safety Guards & Catwalks

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