A depressurization system to treat significant pollution
A former laundry site is currently undergoing a thorough depollution operation following the detection of volatile pollutants, mainly perchloroethylene (PCE) and trichloroethylene (TCE) in the soil.
The intervention was motivated by the presence of impacted ground gases likely to migrate to neighboring buildings via fumes. To remedy this, our teams were commissioned to implement an on-site test to demonstrate the effectiveness of a depressurization system (SDSD).
The technical context was complex: the original concrete slab formed an impermeable barrier promoting the accumulation of volatile compounds under buildings, in a porous soil conducive to gas migration. In order to treat this phenomenon, the solution adopted consisted in drilling the slab to install an under-slab extraction network connected to a treatment unit operating 24/7. In addition, an aerial network has been implemented to avoid congestion on the ground.
In addition, three capture wells positioned at the property line in order to block gas flows in the direction of a neighboring house. Work was also carried out inside it, with the installation of grills ensuring effective air renewal in sensitive rooms.
Preliminary tests carried out at the end of summer 2023 validated the effectiveness of the device, with a reduction in concentrations of around 85% in soil gases. To date, the unit has an operating rate of over 99.99%, thanks to continuous supervision.
The system, active from January 2024 to November 2025, guarantees the sustainable security of the site.