Dissolved Air Flotation Systems

DAF solutions for pre-treatment, biological treatment and tertiary treatment

Dissolved Air Flotation (DAF) has been known as one of the most effective and robust ways to remove suspended solids (TSS), biochemical oxygen demand (BOD5), fats, oils and grease (FOG), phosphorus (P) or nutrients from industrial wastewaters. In response to variations in industrial activity, variations in wastewater and water streams and the ever-demanding customer requirements, Nijhuis Industries has engineered one of the most intelligent and reliable Dissolved Air Flotation systems (i-DAF) available in the North American market.

When selecting a DAF system for your wastewater treatment plant or resource recovery installation, customers typically choose the DAF supplier and equipment based on their industrial experience, quality, performance guarantees and reliability. As a result, Nijhuis has provided more than 3000 Dissolved Air Flotation systems around the world in a variety of industries including; food and beverage production, dairy processing, meat processing, agricultural, oil and gas and municipal markets to just name a few. Furthermore, the Nijhuis i-DAF includes the latest innovations including intelligent design to keep your operational cost (e.g. electrical, chemical and sludge) to a minimum while not impacting treatment performance.

Example of the Nijhuis Dissolved Air Flotation System (type NOF) including the patented i-AERATION system

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Installed DAF system at a poultry processor to treat wastewater


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What is Dissolved Air Flotation and how does Dissolved Air Flotation work?

Dissolved Air Flotation is based on a physical / chemical process, where the injection of air into the water stream with chemical assistance causes the particles/flocks to float to the surface. This floating sludge layer is then automatically and continuously removed by a scraper mechanism. The DAF system will produce a treated effluent virtually free of TSS, FOG and remove a large portion of the BOD.

Depending on the application and the client requirements, the dissolved air flotation unit can be equipped with the Nijhuis Plate Pack Technology which increases the separation area and ensures that even the smallest flocks are removed from the wastewater. Another option is to exclude the plate pack technology and choose Nijhuis Open Flotation Unit Technology to ensure the unit can handle higher solid loadings while still producing a good quality effluent.

Due to the continuous improvements in our patented aeration system, the Nijhuis i-AERATION system and the sludge thickening/scraper system equipped on our DAF systems will result in DAF flotation sludge with a high dry solids content, thereby reducing sludge hauling costs.

What are the Nijhuis Industries Intelligent Dissolved Air Flotation (i-DAF) benefits and features?

  • Maximum TSS, FOG and BOD removal efficiency and reduced energy consumption with the Nijhuis patented i-AERATION system.
  • Reduced installation time as Nijhuis DAF units are shipped as prefabricated units with onboard mounted equipment. Additionally, compact DAF units can be installed in containers, or on a box frame or skid.
  • Suitable for several polluted water types and applications based on the Nijhuis Dissolved Air Flotation material execution.
  • Operational flexibility and reduced sludge disposal with Nijhuis smart level control and sludge scraper system.
  • Reduced footprint with Nijhuis Plate Pack Technology.
  • High solids loading with Nijhuis Open Flotation Technology.

DAF system examples to treat dairy wastewater (picture 1) and food processing wastewater (picture 2)


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Nijhuis Industries Dissolved Air Flotation Systems and Project example for clean and safe water

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Why use and apply Dissolved Air Flotation?

The Dissolved Air Flotation system has proven to be very effective in industrial wastewater pretreatment and has been used in various applications within water, wastewater and desalination applications. To maximize removal of suspended solids and colloidal particles and substances, a flocculator with chemical dosing can be added in front of the DAF. This ensures the polluted water is chemically pretreated before entering the DAF unit thereby providing maximum removal rates (TSS and FOG in excess of 95% is common).

Depending on the application and the clients requirements, a DAF system can be fabricated in stainless steel, or for very large flows, in concrete construction. Most common DAF treatment applications include:

  • Pretreatment for TSS and FOG removal from Industrial wastewater
  • Fats, oils and grease resource recovery
  • Drinking water intake solids removal
  • Water treatment pre-treatment to remove solids and algae blooms
  • Wastewater biological treatment as activated or anaerobic sludge flotation
  • Wastewater tertiary treatment to remove phosphorus and nutrients
  • Pretreatment for Desalination systems
  • Process water production

Nijhuis Dissolved Air Flotation system range:

Click on the product type to get more information on sizes, dimensions, capacity and weight:

  • Compact dissolved air flotation units (IPF / NPF) with plate packs, for low or high capacities per unit.
  • Open dissolved air flotation units (NOF) designed for handling high sludge loadings.
  • Dissolved Gas flotation unit (DGF) using nitrogen-gas or biogas in the aeration system, thus preventing excessive oxygen-levels in the treated water and to meet safety requirements.
  • DAF applications for high capacities (High Rate i-DAF) above 1000 m3/h (4500 gpm) for large scale water production facilities, such as a pre-treatment for surface and sea water.
  • Containerized DAF (ICFF) system based on a plug and play principle, available in boxframe or container configurations ranging from treatment capacities of 5 m3/h to 120 m3/h (25 to 600 gpm).

The Nijhuis Manufacturing Facility (picture 1) and DAF system example at a bacon processing facility (picture 2)


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Let us implement your Dissolved Air Flotation system
for effective solids removal and to keep your operational cost down!

Contact Nijhuis Industries

More than 3000 Dissolved Air Flotation systems installed worldwide

since the 1970's in the food, beverage, meat, dairy, oil and gas, and municipal markets

Dissolved Air Flotation system | Bacon Processing

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Dissolved Air Flotation system | Oil and Gas Industry | Refinery

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Dissolved Air Flotation system | Beef Slaughterhouse

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Dissolved Air Flotation system | Dairy Industry

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Dissolved Air Flotation system | Manure Treatment Industry

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Dissolved Air Flotation system | Plastic Recyling Industry

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Dissolved Air Flotation system | Desalination Industry
Singapore’s fourth desalination plant, the Keppel Marina East Desalination Plant (KMEDP), is unique for its large-scale, dual mode for the treatment of both freshwater from the Marina Bay Reservoir, or seawater.

For the pre-treatment of the seawater, contractor Nijhuis Industries has provided eight high rate dissolved air flotation units for removal of solids.

With a total plant recovery rate of 98%, the Nijhuis DAF units provide a small environmental footprint utilizing Nijhuis plate pack technology. The Nijhuis concrete High Rate i-DAF units have plate packs that make particles/flocks float to the surface with the injection of air.

Large-scale and compact DAF Treatment at the Singapore’s fourth desalination plant, the Keppel Marina East Desalination Plant (KMEDP)

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