Seawater Desalination

Dissolved Air Flotation is playing an increasingly important role in Seawater Desalination Pre-treatment particularly for Reverse Osmosis membrane systems. Algae removal has always been a challenge in the seawater desalination process. KWI’s DAF unit is a proven technology already used in Europe and in the Middle East, as effective pre-treatment upstream of seawater desalination systems. Indeed, Unicell BF (DAF unit) is a robust and simple process to use. Even the stop and start phases do not disrupt its efficiency on algae treatment! Today, there is a constant demand for innovation to improve reliability, reduce CAPEX and OPEX, including the consumption of chemicals from the desalination plant. By bringing together the expertise of KWI, a specialist in pre-treatment by flotation, and ItN, a specialist in ceramic ultrafiltration, we offer an innovative and economical combination:

The DAF system will usually be installed downstream of the seawater intake screens and upstream of the Dual Media/ UF filtration plant. For large flows, KWI offers the Unicell BF (Big Flow) for installation in concrete basins, with our maximum flow being 3000 m3/hr per DAF cell. KWI can also offer a combined DAF filtration system (Flotofilter).

With the unpredictable natural events associated with climate change, we forecast an increase in the number and severity of HAB’s (Harmful Algal Blooms) and red tides around the world. Dissolved Air Flotation is one of the most successful processes for handling both Algae and suspended solids and will contribute to the reduction of organic materials being carried forward to the RO membranes. KWI has a broad experience of supplying both package and large DAF systems to desalination plants in the Middle East, South America and Asia.

Key features and benefits:

  • Outlet turbidity less than 1 NTU
  • TSS removal efficiency: 95%-99%
  • High hydraulic load: maximum 25 m3/(m2.h)
  • High Algae removal efficiency: 95%-98%
  • High sludge concentration: max. 5% of solid content
  • Only seawater resistant materials
  • Low energy and chemicals consumption (High-efficiency DAF)
  • Small footprint


Application sheet

picture gallery