VALGO Environment was mandated by the city of Carignan (Quebec), which wanted to remediate a site where fill material from road works carried out about ten years earlier had been stockpiled. Its aim was to enable a new construction project at this location. Following a public tender launched by the city of Carignan for the implementation of the works, the contract was awarded to Cap Excavation, in partnership with VALGO Environment.
Issue and Objectives
The fill material to be disposed off-site totalized approximately 66,000 cubic meters (120,000 metric tonnes), part of it containing HC C10-C50 type contaminants, PAHs, and metals up to the level B-C. The fill material was at the surface of the site. VALGO Environment’s objective was to supervise the excavation of the soils down to natural ground, and to organize the loading, the transportation and the disposition of both contaminated and uncontaminated soils off-site. VALGO Environment was also required to implement a traceability system for contaminated soils, in compliance with regulations on excavated contaminated soil traceability.
Solutions provided by VALGO Environment
- Organization of the site in all its “environmental remediation” aspects (development of a 3D contamination model for integration into the GPS system of excavators, planning of excavations based on the capacity constraints of disposal centers and analysis of fills to confirm contamination within a polygon or verify excavation walls and bottoms, etc.).
- Transportation of materials and associated traceability.
- Disposal of excavated materials classified as contaminated to the levels A-B and B-C.
During the excavations, it was discovered that the fill materials differed from those described in the characterization report. There were numerous debris, phragmites, and a higher proportion of clay than anticipated. VALGO Environment promptly adapted to this situation and identified new authorized disposal centers capable of accepting these materials.
Details and key figures
- 80,000 tonnes of fill material evacuated
- Duration: 3 months (from January to March 2023)