Contaminated sludge cleanup begins on Spain’s Ebro river to reverse toxic legacy

A 200 million euro clean up operation has started to decontaminate the Flix reservoir on the Ebro River in Tarragona, Spain...

Fcc Web

A 200 million euro clean up operation has started to decontaminate the Flix reservoir on the Ebro River in Tarragona, Spain.

The project has been awarded to Spain’s FCC in 2008 by Acuamed (a company owned by the national government and operated by the Ministry of the Environment).

Up to one million cubic meters of contaminated river sediment will be removed by the project to reverse more than a century of pollution. The pollution arises from toxic waste dumped into the Ebro by a local chlor-alkali plant which began operating in 1897, according to FCC.

It is estimated that the cleanup will take two years and eight months to complete. Project goals are to extract, treat and eliminate the contaminated sludge and subsequently restore the Ebro River and its ecosystem. FCC is responsible for constructing, operating, and dismantling the plant following the completion of the clean-up.

The sludge will be removed and treated in a process that will result in the restoration of the river water to its natural condition. The first step taken was to create a safe treatment location. A 1.3 kilometre-long double wall containment barrier was built to separate the worksite from the riverbed. The worksite was further isolated with the construction of a secant pile wall on the right bank.

The latest stage will see the extraction of about 960,000 cubic metres of sludge contaminated with heavy metals, organochlorides and a certain amount of radioactive elements. This sludge has built up along approximately 1,100 metres of factory wall and extends some 150 metres out into the river. It will be removed by an ecological dredging procedure and treated in the plants that have been set up nearby.

The treatment process will begin with wet sorting, where the materials will be separated and classified. Next the silt will be dehydrated. This dried material will be shipped to a warehouse where it will be stored and analysed so the appropriate treatment can be determined.

Meanwhile, all the water dredged out of the river and extracted during the treatment process will go to a water treatment plant, after which it will be returned to the protected area. Eventually all the material will be shipped to a landfill eight kilometres away that has been built specifically for this project

The project aims to prevent a potential threat to the water supplies of municipalities downstream, as well as the nearby protected Sebes natural reserve.

A fully equipped analytical laboratory has been set up to track the work throughout all its different phases.

The Flix Reservoir decontamination project draws 30% of its funds from the Spanish government and 70% from the European Union Cohesion Fund. There is also a Land Restitution Plan associated with the project, aimed at providing compensation for the people affected by the work.

This associated plan entails another 57 million euros investment, split between the national government (36 million) and the Catalan government (21 million), making for a total investment of over 200 million euros, the biggest investment ever for a decontamination project in Spain, according to the Ministry of Agriculture, Food and the Environment.

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