Shellfish farming

The COLDEP process allows to solve the main technical limits encountered by shellfish purification systems in shellfish installations :

  • Presence of bacteria and viruses in water

  • Abundance of small particles < 30 μm which are not captured by conventional filters and reduce the effectiveness of UV treatments

  • Decrease in dissolved oxygen concentration in the water

  • Accumulation of CO2 dissolved in water

  • Energy costs of solutions to these problems



Particle extraction

The microbubbles created in the system trap impurities during their ascent and create a foam at the top of the column. This scum is sucked up by the vacuum with the particles that are trapped in it :

  • The particles extracted are those measuring between 0.3 and 100μm that are not trapped by conventional systems.
  • In addition to the particles, a large proportion of the dissolved organic matter is extracted.
  • It is possible to extract continuously or only a few hours a day.
  • The energy consumption is between 20 and 30 W/m3 of treated water.






Particle extraction by the COLDEP system also traps bacteria and viruses :

  • The bacterial load is reduced by 99.9%
  • The quantity of viruses in the water is divided by 1000.


Compatibility :

The COLDEP process can also be coupled with and reinforces traditional water treatment technologies :

  •  Water clarification up to 97% transmittance ensures optimum efficiency of UV treatments

  • The extraction function removes the degraded particles that UV and ozone treatments neutralise but leave in the environment.



 echange gazeux coldep

Dissolved gas management 

The bubbles combined with the vacuum created at the top of the column allow for unparalleled aeration and degassing efficiency :

  • The oxygen level in the water is maintained above 90 % saturation

  • More O2 can be injected into the downstream of the column with 98 % dissolution

  • In one pass of the water through the column, the amount of CO2 is reduced by 50 %

  • The energy consumption is between 3 and 5 W/m3 of treated water.

Professional opinion :


SANCHEZ LOGO ROND NB 20200220 1100574

"Our new building includes 230m3 of shellfish purification tanks, for a total volume to be treated of 430m3 recovered directly from the Thau Lagoon. The initial plans included conventional pump technology, sand filters and UV treatment. Exchanging this package for the COLDEP system alone allowed us to reduce power consumption by a factor of eight, and to achieve superior water quality performance in filtration, purification and oxygenation."

Guy Sanchez
Director general











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