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The COLDEP process resolves the main technical limitations encountered by water recirculation systems in fish farms:

  • Decrease in the oxygenation level of the water.
  • Acidification of water, due to too much CO2 dissolved.
  • Abundance of small particles <30µm which are not captured by conventional filters, which clog drum filters and reduce the effectiveness of UV treatments.
  • Energy cost of the solutions implemented to solve these problems.
particulate extraction - water clarification - biosecurity

Treatment of fish water in SAR

Microbubbles created in the system trap impurities as they rise and create a froth at the top of the column. This foam which is sucked up by the vacuum carries with it the particles, then trapped inside. These extracted particles are between 0.3 and 30 µm and are not trapped in conventional systems.

Maximum concentration of suspended solids in treated water

Electricity consumption per m³ of treated water


Reduction of bacterial load

Less viral load

Particle extraction by the COLDEP system also makes it possible to trap bacteria and viruses, thus ensuring the biosecurity of breeding waters. Water clarification also helps to ensure optimal UV efficiency. In addition to particles, a large part of dissolved organic matter is extracted: lhe COLDEP process makes it possible to extract geosmin from water and therefore reduce the presence of off-flavors. There is the possibility of extracting continuously or only a few hours a day.

Dissolved gas management

Regulation of O concentration2, CO2 and N2

The bubbles associated with the vacuum created at the top of the column make it possible to achieve unequaled aeration and degassing efficiency. In addition, the COLDEP process makes it possible toprevent any risk of nitrogen oversaturation.


Minimum oxygen saturation level


Reduction of the quantity of CO₂ in a single pass

CO2 graph
Particulate extraction

Elimination of off-flavors

Thanks to its ability to extract the smallest particles from the water, including dissolved matter, the COLDEP technology provides a solution to the off-flavor problems that have a heavy impact on salmon, sturgeon and very large trout farms.

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  • By removing the geosmin directly from the production basins, the refining and current channel periods can be significantly reduced.
  • In addition to saving time and material, this increases production safety.
  • It is possible to couple the system with ozone or UV production for even better water quality.
The opinion of professionals


At ACIPENSER we have 200 m3 holding tanks for female sturgeons to optimize the taste of their caviar. Before the installation of the COLDEP column, we occasionally encountered off-flavor problems on our caviar. Thanks to the combination of airlift filtration and ozone treatment we were able to remove these unwanted tastes and obtain a constant quality of caviar.

Alexander Warrior

General manager, ACIPENSATE