This decontamination contract is the largest of its kind in Spain to date. Ten consortia (34 companies) bid for the project.

A total of 800,000 tonnes of waste from old industrial discharges has accumulated on the banks of the pond; it must now be properly removed and treated. This toxic waste is comprised primarily of heavy metals (arsenic, mercury, copper, etc.), organochlorine compounds (DDT, PCB, etc.) and other organic compounds.

This contract is part of a larger project managed by ACUAMED, which involves both construction and decontamination. The contract includes building a 1.6-km barrier consisting of a double wall of sheet piles to separate the site from the Ebro river, thereby avoiding seepage and protecting the watercourse.
Environmental dredging will be used to remove 800,000 tonnes of waste from the pond; it will subsequently be treated in plants to be established on-site.

The waste will be sampled systematically on-site to determine its final destination. Some waste will receive additional decontamination treatment using the following technology:

• Thermal desorption.
• Chemical oxidation.
• Stabilisation.

All of the water removed in dredging will be treated at another plant on-site and then returned to the protected area.

Once the waste has been dehydrated and treated, it will be sent along a 6-km-long conveyor belt to a new landfill, whose construction and management is also part of this project.