Automation and Control of the “El Prat” Sea Water Desalination Plant

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.
• 1^st 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.