“It’s a feat! A depollution site of this magnitude, with so many volumes of soil, technical constraints and time, is rare in France. In the teams of the company Séché Environnement, which specializes in the treatment of hazardous waste, satisfaction is evident at the end of the excavation and soil decontamination work. The complex operation was carried out as part of the construction of the future Olympic aquatic center, at Plaine-Saulnier, opposite the Stade de France, in Saint-Denis.
The hunt for hydrocarbons, solvents and heavy metals has been completed on the 12 hectares of what was the former Engie site, historically a major gas production site. In total, 182,000 m3 of earth were disturbed, equivalent to the volume of 66 50-metre swimming pools. Here again, the work exceeded the forecast of 165,000 m3.
And of the 182,000 m3, almost a quarter (50,000 m3) very polluted (tar and hydrocarbons) was evacuated, 40% of which by barge between June and November 2021, from the port of Gennevilliers (Hauts-de-Seine). Around 59,000 m3 of groundwater was also treated and filtered on site.
The development of the future district will be reviewed
“The considerable construction site concerns the only sports equipment left as a lasting legacy of the 2024 Olympics, recalls Patrick Ollier (LR), president of the Métropole du Grand Paris, project owner. We completed the cleanup fifteen days ahead of schedule. It is therefore in less than 14 months that this work of just under 21 million euros was completed.
A performance quoted by Patrick Ollier to once again put an end to concerns about possible delays in the construction of the aquatic center. “It’s a big question that had been asked by detractors: the deadlines, not only do we respect them but we are ahead, he insists. The building permit had been signed a month before the scheduled date and we are on schedule. »
Secured by 90 piles of 17 meters, the size of two and a half football pitches, the huge containment tents dedicated on site to depollution have been dismantled. It was under this tarpaulined metal frame that the technicians, equipped with assisted ventilation masks and wearing disposable coveralls, took charge of the removal by excavator and the evacuation by dump truck of the most contaminated soils located between 3 and 14 m deep.
The construction of the aquatic center for the 2024 Olympics has now begun. On the other hand, the future neighborhood around it, in Plaine-Saulnier, should be overhauled, compared to the elements presented in public consultation, in January 2021 (two-thirds of built-up areas reserved for the tertiary sector, 500 housing units, a body of water …). “We haven’t decided yet,” says Patrick Ollier. There may be fewer offices, perhaps more housing, we don’t know yet. We are going to move to a 1.5 hectare park. But on the general organization, we can not say anything more for the moment. We will see what the city and the territory want, it is a partnership discussion. We are going to develop the project so that it is adapted to our times. »
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