As part of an industrial remediation project, one of the most technically challenging aspects of the remediation can be soils containing leachable metals, in this case copper and lead, as this soil can be determined to be a hazardous waste under the BC Hazardous Waste Regulations. This presentation will share an on-site solution to chemically immobilize the copper and lead, rendering the soil non-hazardous prior to shipment off-site for disposal. The process starts by excavating the leachable copper and lead soil and stockpiling it into a poly-lined bermed cell. The calcium polysulfide solution required by the mix design is transferred from the reagent storage tank to the stockpiles to be treated using a chemical pump, a flow meter and flexible hoses. Super sacks of Portland cement, as required by the mix design, are added to each stockpile. Excavator mixing is employed to mix the calcium polysulfide and Portland cement into the soil. The excavator operator lifts, turns, and folds the amended stockpile for a minimum of 90 minutes or until the stockpile material is visually homogeneous with respect to color and moisture.

After treatment, samples are collected from the treated stockpile within 24 hours after treatment and submitted for toxicity characteristic leaching procedure copper and lead analysis. Once the metals are determined to be non-leachable, the treated soil can be properly disposed of off-site. This simple and cost-effective solution can be added to a complex part of the overall remediation project.

Chris Brown, Senior Project Manager, Matcon Environmental Ltd.
Chris Brown, B.Sc., PMP, is a senior project manager in the environmental contracting industry with over 20 years of experience in both environmental consulting and contracting. He has held project management roles in businesses specializing in hazardous materials abatement, demolition, site remediation, waste management and environmental investigations.

Since 2010, the Government of Canada has become the owner of several brownfields with major environmental issues with Public Services and Procurement Canada (PSPC) finding itself in the role of manager as the custodial department under the Canada Business Corporations Act (CBCA). Included among these is the old Sambault landfill site. Located on the south shore of Montréal (Montérégie), in Saint-Isidore-La-Prairie, the approximately 150,000 m² site was subjected to illegal waste dumping between 1965 and 1986.

As the site was known to be contaminated and that it might potentially pose risks, PSPC’s Environmental Services (ES) quickly took measures to ensure that the health and safety of the public was not compromised and that due diligence measures were taken regarding the site. Since 2011, several environmental assessments (ESA, phases I, II and III), quality monitoring of the groundwater and surface water, as well as an analysis of the toxicological and ecotoxicological hazards was completed. Studies revealed that the environmental quality of several media exceeded the applicable criteria/recommendations for the property and spurred urgent action to avoid contamination to the water source for local residents by chlorinated solvents.

In conducting this comprehensive environmental analysis, PSPC used an innovative contractual approach in order to make use of the services of a firm specialized in the environment (Consultant) by launching a public call for tenders for a mandate that included all the expected steps of the project including environmental characterizations, the development of site remediation scenarios, the preparation of plans and the supervision of the remediation work. Afterwards, in order to implement the remediation solutions developed by the specialized firm in collaboration with ES, PSPC also had to adopt an unconventional contractual approach. In fact, the remediation work included a Construction component (partially prescriptive and partially objective-based) for the implementation of the environmental mitigation measures, as well as an Operation/Maintenance component for the pumping and treatment system. This contract was awarded through a public call for tenders to a specialized firm.

This presentation will highlight the approaches recommended by PSPC’s ES to ensure the effective and optimal management of the environmental issues identified for this site.

Morgan Le Garrec, Senior Environmental Specialist, Environmental Services Team, Public Services and Procurement Canada
An engineer-geologist with a specialization in hydrogeology and the environment, Morgan Le Garrec has more than 16 years of experience in large project management in the environmental field. After 12 years as an environmental engineering consultant in the private sector, Mr. Le Garrec joined the Environmental Services team at Public Services and Procurement Canada (PSPC) in 2015 where he currently works as the senior environmental specialist.

Background
Located in eastern Michigan, Liberty Park is a brownfield site situated on top of an unstable landfill that has environmental impacts due to incinerator waste that caused many environmental challenges, including vapor intrusion.

Seeing a growing demand for high-end office and industrial warehouse space, Ashley Capital, a leading commercial real estate company, purchased Liberty Park with plans for redevelopment. They recognized that development at this property would require a unique foundation to counter the underlying geological instability and an effective vapor intrusion mitigation (VIM) solution to protect occupants from health hazards.

Approach/Activities
After exploring several VIM options, Ashley Capital decided to implement MonoShield, a regulatory approved, single 30 min layer geomembrane sprayed-seam vapor mitigation barrier system. MonoShield is comprised of an innovative chemically resistant metalized film and nitrile-based asphalt latex that ensures an effective seal against harmful vapors. The nitrile core is used to spray the seams, penetrations, and perimeter. It can be installed 20-30% faster than alternate plastic sheeting or high-density polyethylene (HDPE) systems, has high constructability, and is highly cost-effective. It also eliminates concerns with leaks and tears through the use of the spray nitrile core, puncture resistance base layer and the QA/QC testing conducted (smoke testing) during installation, which is typically not the case with traditional tape and roll systems.

The size of the building (570,000 ft2) also necessitated a solution to mitigate the expense of pumping concrete over long distances. The site was prepared with an 8-inch layer of stone on top of MonoShield followed by building slab. The durability of MonoShield allowed for this construction sequence to be provided. This unique profile provided a buffer area for utilities and a structural component allowing for concrete to be poured directly from a truck inside the building.

Results
This was the first ever application of MonoShield, which was reviewed and approved by Michigan’s Department of Environment, Great Lakes and, Energy (EGLE), as a result of its successful installation, Liberty Park is now pre-emptively protected against harmful vapor intrusion utilizing a technology that was both time and cost efficient.

Ryan Miller, East Region Manager, Land Science® division, REGENESIS, Inc.
Ryan Miller is the East Region Manager of the Land Science® division of REGENESIS, Inc., and is based in northern New Jersey. Ryan’s role includes providing technical support in the design and installation of TerraShield, Nitra-Seal, MonoShield, Geo-Seal and Retro-Coat vapor mitigation systems, and educating the environmental community on the advancements in vapor intrusion barrier technology, implementation, and quality control by making presentations to environmental firms, regulatory agencies, and developers. Ryan has extensive experience in the environmental consulting industry, most recently working as a New Jersey Licensed Site Remediation Professional (LSRP) focusing on brownfield redevelopment projects and specializing in vapor intrusion mitigation. Ryan earned an MBA from Montclair State University and a Bachelor of Science degree in Environmental Studies from Siena College.