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Automation and control of the "El Prat" sea water desalination plant

Estación Desaladora de Agua Marina

The desalination plant in El Prat is the Europe´s largest desalination facility to supply human as well as in terms of constructive and technological solutions adopted, complying with stringent environmental premises.

General plant data

  • Sea water desalination plant design flow: 200,000 m3/day
  • Unit flow: 4,200 m3/hour
  • Intake: 5+1 pumps
  • Number of signals: 29,874
  • Desalination process by reverse osmosis
    • Conversion factor: 45%
    • Salinity of seawater: 39,700 ppm
    • Salinity of product: 110 ppm
    • Salt removal performance: 99.7%


SICE carried out the supply, installation and start-up of the automation and control systems of the desalination plant, through a SCADA control system and redundant PLCs. For this, the company accomplished detailed engineering, supply of materials, manufacturing of telecontrol cabinets, installation, software application development, commissioning, final documentation and customer training.

The works and facilities that form the desalination plant are:

  • Seawater catchment with open intake, by submarine outfall formed by two pipes of 1,800 mm (diameter) and 2,200 m (length).
  • Seawater pumping station, located on El Prat beach.
  • Seawater drive to the desalination plant, with a pipeline of 2,400 mm (diameter) and 3,100 m (length).
  • Chambers of mixture and flocculation, with addition of chemical reagents.
  • Clarification by flotation.
  • 1st stage filtration with covered filters.
  • Microfiltration with cartridge filters.
  • Pumping of high pressure by feeding to reverse osmosis racks.
  • Reverse osmosis in ten semipermeable membrane frames contained in pressure tubes.
  • Energy recovery through pressure exchange systems.
  • Post-treatment with remineralization.
  • Water tank product and pumping to the Fontsanta distribution tank.
  • Evacuation of the reject brine to the emissary of the Llobregat WWTP.
  • Effluent treatment with mixing and flocculation, decantation, thickening, dehydration and sludge evacuation.
  • Electrical and control systems.


Significant challenges on this project include:

  1. Project Management: Coordination of the project with Degrémont and AGBAR (Joint Venture), including documentation, review and approval.


  1. Cabinets and supplies: Detailed engineering for construction of control cabinets. Equipment supply (Siemens and cabinet components). Manufacture of control cabinets Control cables (Profibus DP and PA, modbus and fiber optics)


  1. Development: Control software developed (from the customer functional specifications). Integration of equipment buses to the control system (based on the manufacturer specifications).


  1. FAT, installation, commissioning and testing: Exhaustive testing FAT for the control cabinets and communications bus with PLCs. Control buses connection. Commissioning and startup of the system. Delivery of the system.


  1. Training and final documentation: Operator training and final documentation.