Your challenges
Maximizing treatment performance and operational flexibility in limited spaces.


Unstable performance with varying water types
Traditional dissolved air flotation (DAF) systems often struggle with fluctuating flows and different water types. There’s a need for a solution that is robust, adaptable, and effective for fresh, salt, and brackish water applications.

Frequent clogging and high maintenance
Many conventional systems suffer from clogging and require frequent maintenance due to inefficient aeration systems. A clog-free, reliable aeration solution is essential to minimize downtime and operational costs.

Limited footprint with high-quality demands
Achieving high effluent quality while maintaining a small footprint requires advanced skimming and separation technologies that offer stable and efficient performance.
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How does it work ?
The NSI HR-DAF is a dissolved air flotation system designed to efficiently separate suspended solids, fats, oils, and grease from water, even under fluctuating flow conditions based on the unparalleled ‘Nijhuis dissolved air flotation’ expertise.
The process
The HR-DAF is engineered using a combination of patented and optimized components:
- Aeration system: Water is pressurized and saturated with air. When released into the flotation tank, it forms fine microbubbles ranging between 30 to 60 microns. These bubbles attach to suspended particles, causing them to rise to the surface.
- Integrated plate pack: Inside the tank, an inclined plate pack stabilizes the laminar flow of water, increasing the separation surface area and improving particle flotation and clarification efficiency. This allows the system to handle much higher hydraulic loads (over 40 m³/m²/h) than conventional dissolved air flotation systems.
- 3-wheel skimmer system: At the water surface, a unique 3-wheel skimmer gently removes the flotation sludge layer, guiding it towards a dedicated beach area. This ensures consistent removal of solids and minimal backflow of floating materials.
- Smart effluent valve: This valve maintains a constant water level inside the DAF, even when flows fluctuate. It also allows the floating layer to be fully removed before system shutdown, helping prevent residual solids buildup and simplifying cleaning.
- Clog-free operation: The patented aeration system ensures consistent bubble formation without clogging, reducing maintenance requirements and downtime, which is especially valuable in variable or difficult water conditions.
Applications
The NSI HR-DAF is a versatile flotation solution used in a variety of water and wastewater treatment applications, providing reliable performance in different operational environments.
- Drinking water production: Removing suspended solids, algae, and organic matter from raw water sources such as rivers, lakes, and reservoirs.
- Desalination plants: Pre-treatment and post-treatment in seawater desalination processes, ensuring the removal of fine solids and improving the lifespan of membranes and downstream equipment.
- Municipal wastewater treatment: Enhancing primary, secondary, and tertiary treatment processes by removing fats, oils, grease, and suspended solids, improving overall plant efficiency and effluent quality.
- Industrial wastewater treatment: Managing effluent from industries such as food and beverage, dairy, oil and gas, textiles, and chemicals, where high concentrations of organic matter and suspended solids require effective separation.
- Sludge thickening: Concentrating sludge solids before further treatment or disposal, reducing sludge handling costs and improving process efficiency.
Customer benefits
The NSI HR-DAF combines wide applicability with high-quality effluent, clog-free aeration, operational flexibility, enhanced sludge removal, and a compact design that delivers superior separation performance at reduced footprint and cost.


Widely applicable
Applicable to large-scale desalination, drinking water and wastewater treatment plants.

High-quality effluent
Delivering clean, high-quality effluent while minimizing operational costs and footprint.

Clog-free aeration
Patented clog-free aeration generates fine 30–60 micron bubbles, preventing clogging, reducing maintenance, and ensuring continuous, reliable operation.

Operational flexibility
A smart effluent valve keeps the water level constant under fluctuating flows, allowing complete flotation layer removal before shutdown.

Enhanced sludge removal
The unique 3-wheel skimmer system ensures efficient and gentle removal of flotation sludge, improving sludge handling and effluent quality.

Reduced footprint & improved separation
The integrated platepack increases the effective separation area, enabling hydraulic loading rates over 40 m³/m²/h, outperforming typical dissolved air flotation systems in a smaller space.

Key figures
""The NSI High-Rate DAF is a compact, scalable, and clog-free flotation solution that combines operational flexibility with outstanding separation performance." "
NSI High-Rate DAF
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Frequently asked questions
What differentiates the High-Rate DAF from conventional DAF systems?
The HR-DAF offers clog-free aeration, a smart effluent valve, and an integrated platepack for improved separation rates, handling higher hydraulic loads in a smaller footprint.
Can it handle fluctuating flows or different water types?
Yes. It is designed for fresh, salt, and brackish water, with smart systems maintaining performance and water levels even under variable flow conditions.
How does the 3-wheel skimmer improve performance?
It gently removes the flotation layer with minimal backflow, ensuring consistent sludge removal and maintaining optimal effluent quality.
What are the operational benefits of the clog-free aeration system?
It prevents clogging, reduces maintenance, and ensures continuous bubble production for reliable flotation performance.
How compact is the HR-DAF compared to conventional systems?
Thanks to the integrated platepack, it offers hydraulic loading rates over 40 m³/m²/h — far above typical DAF systems — enabling higher capacity in a smaller space.
Where is HR-DAF already in use?
Installations include Singapore’s Marina East Desalination Plant, Mexico’s Madin Dam, Ivory Coast LWTP, and Uganda’s Ggaba WTP.