Remediation of the site of a former service station through an in-situ passive treatment

The municipality of Val-Joli is part of the Regional County Municipality (RCM) of Val-Saint-François, in the Estrie administrative region. It has 1,600 residents and a total surface area of about 90 square kilometres. The site to be rehabilitated includes a commercial and residential building along with a parking area. Due to its convenient location, this site was formerly occupied by a service station with an adjacent convenience store. Studies have shown the presence of gas-related surface contamination as well as contamination underneath the building, which prevents the completion of economically viable projects.

The goal of this pilot project is to rehabilitate the property into commercial/residential rental spaces through a treatment for contaminated soils that uses a new in-situ technology. The technique selected combines high-capacity and high-purity activated carbon (drinking water approved) with complementary amendments. Through biotic or abiotic processes, these amendments will make it possible to treat the contaminants, which will be balanced by activated carbon. The use of activated carbon is relevant in cases where contaminants are being slowly discharged into the soil or when the contamination affects underground water. This is an innovative passive technique that is being applied for the first time in Quebec; it is also cheaper than conventional methods. It will be replicable in other municipalities or other privately owned sites. A rehabilitation plan using the technique proposed for the decontamination of the former service station site was approved by the ministère de l'Environnement et de la Lutte contre les changements climatiques (Quebec Department of the Environment and the Fight Against Climate Change, or MELCC).

Innovative aspects

• The selected treatment technology (activated carbon) is being applied for the first time in Quebec.
• The activated carbon-based in-situ treatment could allow smaller municipalities to decontaminate sites at a lesser cost and with fewer environmental impacts.

Replicability

The replicability and the ability to learn lessons and share knowledge are very good. The pilot project has a high replicability potential for Quebec and the municipality of Val-Joli since there are many orphan sites requiring decontamination or rehabilitation. This technology could be a very interesting option for small- and medium-sized municipalities that are often dealing with the problem of buildings with contaminated subsoil (municipal garages) or streets with several contaminated structures.

Environmental benefits

• Rehabilitated surface water, underground water or soil: 320 m3
• Volume of contaminated soil reused on-site: 200 m3
• Area made available for reuse: 0.086 ha

Economic benefits

• Increase in the site’s value and economic potential
• Increase in municipal cash flows (property taxes)

Social benefits

• Revitalization of the community through the renewal of the site
• New housing units and commercial rental spaces