Solutions for seawater pre-treatment

UNICELL BIG FLOW (UNC BF) for Seawater Desalination Pre-Treatment

UNICELL BF is KWI´s high-performance Dissolved Air Flotation (DAF) clarifier, developed for Seawater Desalination Pre-Treatment.

  • Designed to treat large seawater flows
  • Only seawater-resistant materials
  • In-house developed, highly efficient aeration unit
  • High removal rates
  • Low energy consumption
  • Low chemical consumption
  • Fully automated operation

UNICELL BF is a tailormade and customized Seawater DAF and able to treat up to 3,000 m3/hr per unit. For larger flowrates a specifically engineered multicell arrangement ensures a compact design with low footprint and high removal rates.

For large seawater flows UNICELL BF is the proper technology to remove low-density particulate matter such as e.g. Algal Organic Matter (AOM), Total Suspended Solids (TSS), turbidity or oil and grease. DAF operates with small, low density flocs and specifically light particles.


Our experiences in seawater pre-treatment


Optimization of the Pre-Treatment before Filtration and Reverse Osmosis through extensive removal of algae resp. Algal Organic Matter (AOM)

Filtration membranes are exposed to mainly two fouling mechanisms:

  • Biofouling is caused through bacterial growth on the membranes surface, which is generally supported by Transparent Exopolymer Particles (TEP) that form sticky layers and provide the right environment for biological growth.
  • Particulate Fouling means the deposition of algal particulates on the membranes along with other organic colloids and materials. Supporting nutrients for bacterial growth, particulate fouling triggers the biofouling mechanism.

Finally fouling layers will lead to a systematic decrease of membrane performance. This means a reduction of permeate flux (conversion rate) or consequently an increase of pump pressure to maintain water production.

Consequently backwashing resp. Cleaning in Place (CIP) will be necessary to remove fouling layers and recover membrane performance. But as the fouling layer normally is only partially removable through its sticky nature, permeability will decrease progressively over time. This addresses the non-backwashable type of fouling.

Unicell BF benefits for Membrane Operation

  • Energy Savings: As AOM is reduced there will be less fouling and hence less pressure loss through the membranes. Consequently, less pump power maintains water production.
  • Chemical Savings: As AOM is reduced there will be less need for backwashing of the membranes. As Transparent Exopolymer Particles (TEP) are removed by DAF – TEP form a sticky supporting layer for other AOM and cause biofouling – the non-backwashable type of fouling is reduced as well.

DAF provides a smooth removal process with low shear input. Thus, algal cell lysis is prevented and the release of fouling organics and algal toxins is mostly avoided.

>>> The Removal of AOM through KWIs UNICELL BF – DAF system will lead to an extension of the overall membrane lifecycle.

Smart DAF for Smart Control

  • Fast response to Harmful Algal Blooms (HAB)
  • System optimization
  • Remote analysis and support