Our quality commitment
Work methods and procedures are checked constantly using a quality control program. This control is applicable to all stages of the process, as well as to laboratory analyses, research, waste treatment, etc.
Thermal soil treatment unit
The soil treatment unit uses thermal desorption technology to extract organic contaminants from soil. The contaminants collected are then destroyed at a very high temperature. Finally, the purified gases are cooled and filtered, and their residual acidity is neutralized. These facilities have a minimum efficiency rate of 99.99%.
The maximum-security containment cells at the Grandes-Piles Centre can receive soil with a level of contamination below the standards of Annex 1 of the Regulation respecting the burial of contaminated soils (RESC). Cells are dug into the layer of clay itself. There must be at least three metres of clay below the cells. This impermeable clay constitutes a natural shield, preventing contaminants from seeping into groundwater. But the protection doesn't end there. The bottom and sides of the cells are covered in two high-density polyethylene membranes separated by a geodrain.
Additionally, cells are surrounded by a watertight, vertical wall made of liquefied clay. Cells are equipped with a leachate collection pump system. Pumped water is collected in basins and treated.Once full, cells are capped using two watertight geomembranes and two geotextiles covered with sand and topsoil. A venting system is installed.See a cross-section diagram of a cell.
The water treatment facilities consist of five basins and a water treatment plant. The basins are dug in the clay layer. The bottom and sides are covered in a watertight high-density polyethylene membrane.
The water treatment process consists of several steps:
- adjustment of pH if necessary
- Gaf filter
- sand filter
- filter for organic compounds
- activated carbon filter
- carbon filter for mercury
Once treated, water is kept in a basin while undergoing analysis. If the water quality does not meet the required criteria, the water is retreated. Once it meets standards, water is discharged into the surface water system.
The Grandes-Piles Centre benefits from exceptional hydrogeological conditions. It is built on flat land consisting of a layer of sand 0.3 to 3 metres thick. Beneath the sand layer, there is an impermeable clay layer that may be up to 27 metres thick. This clay layer forms a natural barrier between the containment cell and the water table.