RÉALISATION

Characterization and Environmental Rehabilitation

Client:

Car dealership

Objective:

This project comes as part of a change of activity on the site

Scope of work:

A Phase 1, was first performed by Terrapex on this site occupied by a car dealership and a mechanical repair garage associated with the dealer’s activities. Phase 1 revealed that the site was occupied by several buildings housing commercial and industrial activities in the past. Following the recommendations of the Phase 1, an environmental characterization Phase 2 study was conducted. Boreholes have been converted into observation wells. The characterization identified the presence of contamination by petroleum hydrocarbons, PAHs and metals in soils and groundwater with concentrations above the allowed levels for commercial zoning as well as the presence of a large volume (20 000 m³) of residual materials. The site is considered a non-registered disused disposal site. The ultimate goal of the customer is to build buildings for commercial use, the project was realized within the framework of Article 65 of the Law on Environmental Quality (building on a abandoned landfill).

An additional environmental characterization for verification of biogas concentrations combined with a risk analysis as well as monitoring the quality of groundwater has been made following the Phase 2 because of the problems related to the residual waste and contamination of groundwater. Methane concentrations in excess of the legal limit were measured in the horizon of residual materials.

For all governemental approvals, Terrapex set up a rehabilitation plan including a building decommissioning plan, an application for permission to build on a landfill and design mitigations measuresfor the presence of biogas and recommendation of the risk analysis study. Terrapex supervised the work of environmental rehabilitation of the site following the rehabilitation plan approved for MDDELCC. In all, some 6800 M.T. of soil contaminated with petroleum hydrocarbons C10-C50 were sent to a treatment center. The majority of the contamination was at a depth of 7 meters to 11 meters. The methods of mitigations biogas were implemented under the supervision of Terrapex. During this work, advantageous technical solutions were made by Terrapex the benefit of the customer for the design of the retaining walls. Terrapex also provided oversight during the implementation of building foundation piles.

Finally, Terrapex contributed to obtaining government grants under the ClimatSol program. Terrapex has been present from the beginning to the end of the construction project.

SPECIAL CONSIDERATIONS: The  site was occupied for many years by various industrial and commercial activities generating a  diversity of contamination and waste streams. Consequently, the project involved several regulatory levels for cessation of activity, for the change of activity and the risk analysis of the residual wastes.