Executive Summary
AEL completed a Phase Two Environmental Site Assessment (ESA) and a full-depth, remedial excavation program at a remote, decommissioned microwave tower facility in Northern Ontario. The goal of the project was the restoration and return of the land leased to the client by the local First Nation community.
Prior investigation had identified soil contamination associated with leaking aboveground fuel storage tanks. A groundwater plume of petroleum compounds had impacted a large area around the site. AEL assumed the role of on-site environmental consultant part-way through the project. AEL conducted a Phase Two Environmental Site Assessment (ESA) and complete soil remediation following partial remedial work by a prior consulting firms over the previous decade.
A thorough review of existing material was conducted upon taking control of the remedial aspects of the project. Groundwater control was identified as the root cause of previous costly project delays. Our team of experts implemented a comprehensive groundwater management plan built around a pump-and-treat system to manage contaminated water entering the excavation.
To meet the unique constraints of remote remedial work, AEL developed a custom soil management plan based around high-frequency and affordable on-site testing certified by low-frequency laboratory analysis. This management strategy reduced delays and costs, allowing the project to be completed under-budget within 18 months of AEL’s first arrival onsite.
Introduction
This case study took place on a fly-in/winter road-accessed remote location in Northern Ontario. Due to the origins of this property, the site was being returned to its rightful owners, the local First Nation community. AEL was welcomed aboard to complete environmental work at the decommissioned microwave tower facility.
Problem
Previous environmental work at the site had revealed contamination associated with leaking aboveground storage tanks, resulting in petroleum hydrocarbon impacts (PHCs), volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), and metals in soil and groundwater.
AEL noted that groundwater had not been adequately controlled during previous remedial efforts. The site was located between a wetland and lake, resulting in complex groundwater flow and highly saturated flowing sand conditions.
Solution
The pumping and dewatering system was developed, tested, and later installed to prevent contaminated groundwater from entering the excavation pit. Afterwards, AEL was free to address the remaining contaminated soil.
The remediation process involved an on-site water treatment program. With excavation supervision screening of samples using UVF spectrograph on-site, AEL was able to minimize sampling costs and quickly characterize the site. Confirmatory samples were then sent to a certified laboratory for verification of findings. Regular drone surveys of the site were also completed during excavation, allowing for the interpretation of valuable site data to help accurately guide excavation. With AEL’s expert guidance, the excavation of and disposal of 2,700 cubic metres of contaminated soil was completed and the site closed, with long-term monitoring to follow.
Impact
This unique project was a tremendous success for everyone involved. Throughout the entire investigative and remedial process, our team was committed to attending regular meetings with clients and representatives, along with First Nations Leaders. All issues were discussed in consultation with these project partners, including the status of remedial work, budgets, and time management by on-site testing. Findings were always discussed with First Nation leadership to address the concerns of the local band while also meeting regulatory compliance. In the end, we managed to significantly reduce timelines and budget requirements. Consequently, the client was able to close the site much earlier than initially projected by previous consultants.
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