Seawater Treatment

PSC S.p.A. Engineering & Contracting (PSC) with its highly specialized personnel has an extensive experience in the treatment of seawater. The treated water can be used for different purposes, such as drinking water production, to feed a demineralization plant (DEMI), for irrigation and other industrial services.

Seawater contains high salinity, total suspended solids, some total organic carbon, algae content, that is not suitable for the industrial service such as drinking, and injection water to enhance the oil production and water boiler feeds.

Here below is described a process flow treatment that PSC can design, to treat seawater:

• Coarse and fine screens as primary treatment to remove the solids as sand, mussels, algae from the seawater, protecting the next process step;
• Granular filters or Ultrafiltration membranes to remove the fine suspended solid particles, reducing the turbidity, colloidal and suspended organic matter, within the allowable limits to desalination steps.
  The selection of this filtration process depends on the seawater intake design, feed water quality, available plant area;
• Nanofiltration or seawater desalination to remove the dissolved organic and dissolved salts. Usually nanofiltration performs enough for water injection service to oil field production. Seawater desalination allows a quality of water to be fed to next polishing ion exchanger or mixed beds or to send to a remineralisation process;
• In the case of the presence of gases, vacuum deoxygenation is used to remove any dissolved gases from seawater such as carbon dioxide and oxygen. Degasification is required for the water injection in oil field production (generally a degasifier tower is used);
• Remineralization step, where hardness salts are added to desalinated water to get a drinking water. The remineralization process can be performed by chemical injections and by limestone dissolving.