The City of Saguenay alerted MDDEFP (Quebec’s ministry of sustainable development, environment, wildlife, and parks) to complaints about gas odours inside homes downwind from a service station. MDDEFP ultimately discovered gasoline in the sewer line running underneath these homes. Characterization studies revealed contamination on three residential properties and in and around a municipal street. MDDEFP issued an order to build a contaminant interception trench, draw up a rehabilitation plan, and rehabilitate the contaminated properties.
Since contaminants had migrated under the homes’ foundations, the buildings required supports so that all contaminated soil underneath could be excavated.
Savaria Experts-Conseils was responsible for supervising the work, taking soil and water samples, and monitoring the interception trenches. Once the sites were decontaminated, two multiphase extraction systems were installed between the service station and residential properties to intercept any residual contamination in groundwater and prevent any further contamination from migrating into the rehabilitated properties.
Savaria Experts-Conseils continues to conduct periodic testing of the water treated by the extraction systems as well as gaseous effluents from the installed control wells. In addition, a vapour monitoring program was set up to evaluate the dedicated vapour treatment systems set up in the homes.