SOIL REMEDIATION OF A FORMER POWER PLANT SITE IN TULITA, NORTHWEST TERRITORIES

• Main Authors: Yvan Pouliot, Nicolas Moreau, Eric Thomassin-lacroix
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Northwest Territories; Canada; Great Bear Lake; Tulita; Sahtu Region
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.498.6062; http://www.esaa-events.com/remtech/2005/pdf/Paper39.pdf

The Dene Hamlet of Tulita is located east of the Great Bear Lake, at the junction of the Mackenzie and Great Bear Rivers, in the Sahtu region of the Northwest Territories. For 22 years, this Hamlet hosted a power generating plant whose operations, together with some accidental petroleum hydrocarbon (PHC) spills, caused a high level of soil contamination, specifically in the peat layer found in the soil. The dismantling of the former power plant and subsequent decommissioning of the site required that the site be remediated. Project challenges stemmed from the high level of soil contamination (up to 185,000 mg/kg in the peat layer) and the remote location of the community, which is only accessible by plane and barge during the short summer season. As the site was located in the center of the Hamlet, efforts were made to minimize the project impacts (odours, noise, dust, safety) to the surrounding community members. The project commenced in June 2002. The remediation guidelines used were Canada-Wide Standards (CWS) for PHC in soil, from the Canadian Council of Ministers of the Environment (CCME). In order to achieve the remediation objectives established for this project, Biogenie used its proprietary treatment process, the In situ Biopile. A volume of 8,100 m3 was treated inside the land treatment area (LTA) at an average depth of 3.0 m below ground surface. At the start of the project, the average PHC (Fractions 1 to 4) concentration was 12,500 mg/kg (n = 26). After 14 months of treatment, this concentration was reduced to 2,496 mg/kg (n = 27) representing an average removal rate of 80%. This paper outlines each major stage of the project, focusing mainly on the technical and human challenges that were encountered and how they were overcome.