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Reverse Osmosis (RO) Desalination plants

Physical desalination processes allow to separate water from a saline solution using mechanical energy instead of thermal energy. The most diffuse method of physical desalination is the reverse osmosis (RO).

Since 1988, Fisia Italiampianti has completed several RO Desalination plants, both from seawater and brackish water, in several countries. The Company aims to contribute to sustainable growth of RO technology, improving know-how and competences. To this end, Fisia Italimpianti realized a pilot plant in Genoa Port for the optimization of the process and to control the fouling phenomena. RO system, become the preferred choice for the new installations, and is made up of the following four basic phases:

  • Pretreatment
    Fine filtration and the addition of acid or other chemicals to inhibit precipitation and the growth of microorganisms;
  • High-pressure pump
    It supplies the pressure needed to enable the water to pass through the membrane and have the salts rejected. This pressure ranges from 15 to 25 bar (225 to 375 psi) for brackish water and from 54 to 80 bar (800 to 1,180 psi) for sea water.
  • Membrane assembly
    It consists of a pressure vessel and a membrane that permits the feed water to be pressurized against the membrane. The membrane must be able to withstand the entire pressure drop across it. The semi-permeable membranes vary in their ability to pass fresh water and reject the passage of salts.
  • Post-treatment
    The potable water quality required is reached by means of remineralization plant using CO2 and limestone.