Barcelona turns sea water into drinking water

Spain, like other countries, has experienced a drop in its natural water reserves. In 2008, in a situation of severe hydric stress, Barcelona adopted reverse osmosis desalination of seawater, one of the specialities of SUEZ. The Catalan authorities entrusted the group with the construction of the largest plant in Europe, and gained a drinking water production capacity of 200,000 m3/day
The mission

Deploy our desalination technologies 

In the mid 2000's, the situation for Barcelona and its surrounding region was a cause for concern. The drinking water reserves required to supply over four million inhabitants had fallen to 20.5% of the normal level. Restrictive measures on water use were implemented and for three months tankers delivered water reserves from Tarragona and Marseille to meet the emergency needs.

Under the national hydrology plans, the Catalonia authorities turned to SUEZ to discuss innovative, sustainable solutions to transform seawater into drinking water.

litres of seawater
when desalinated can produce 45 litres of drinking water 
people in the world are supplied with desalinated drinking water
behind the USA, Spain is the most prolific user of desalination technologies
Our solution

Take the sea as an ally

SUEZ was entrusted with the design and the construction of Barcelona's desalination plant, the largest in Europe. We were therefore able to manage the water supply for urban areas while also:

  • reducing withdrawals from drinking water supplies
  • limiting the use of surface water
  • respecting biodiversity and the marine ecosystem

SUEZ is renowned for its leading edge skills in seawater and brackish water desalination technologies and in the reuse of treated wastewater. The two main technologies implemented in the Barcelona plant were:

  • reverse osmosis for desalination (membrane separation), 
  • ultrafiltration and disinfection processes for the reuse of wastewater.


The results

A reliable, high-technology treatment line

SUEZ implemented a reliable, high-technology treatment line generating high yields, especially for purification operations:

  • Pilot facilities were used to analyse osmosis pre-treatment, the elimination of soluble organic matter and brackish rejections. 
  • Then two 12-metre high towers were built underwater, 2.2 km off the coast. They capture 450,000 m3 of seawater every day.
  • The plant is very energy-efficient due to the reverse osmosis technology. Even better, it can recover and save 50 % of energy consumption. 
  • Environmental issues are also key in this marine environment. Water intake at a depth of 25 metres and the pumping speed limit the intake of living organisms such as fish.


of the region's population is supplied with drinking water from the Barcelona desalination plant
the plant's drinking water production capacity
the amount of salts filtered out by the membrane separation technology (reverse osmosis).