Dissolved Air Flotation Systems-

DAF Solutions for Pre-Treatment, Biological Treatment, and Tertiary Treatment

Dissolved Air Flotation Systems

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 worldwide in various industries, including; food and beverage production, dairy processing, meat processing, agricultural, oil and gas, and municipal markets, to 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.

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.


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

Dissolved Air Flotation is based on a physical/chemical process, where air is injected into the water stream and 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 removes a large portion of the BOD.

Depending on the application and the client’s 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 choose Nijhuis Open Flotation Unit Technology to ensure the unit can handle higher solid loadings while still producing 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.

Why Dissolved Air Flotation?

The Dissolved Air Flotation system has proven very effective in industrial wastewater pretreatment and has been used in various water, wastewater, and desalination applications. To maximize the 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 client’s requirements, a DAF system can be fabricated in concrete construction or, for very large flows, in stainless steel. The 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

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