In Montreal, Quebec, the Dow-Petromont rehabilitation project, a decade-long process and collaboration between Dow Chemical Canada ULC, Petromont, and WSP Golder, has revolutionized sustainable remediation and technological innovation. With approximately 190,000 cubic meters of soils successfully treated through biopiles, and an additional 35,000 cubic meters of soils undergoing rhizodegradation.

This project was recognized with a prestigious Brownie Award in the Remediate category last year, demonstrating the power of collaboration and cutting-edge solutions in revitalizing contaminated sites.

The Dow-Petromont rehabilitation project addressed the environmental challenges posed by a former petrochemical manufacturing complex and remediated a large-scale biopiling site. In 2010, laboratory treatability tests conducted at Golder’s facilities revealed the difficulty of degrading heavy molecular polycyclic aromatic hydrocarbons (PAHs) under conventional aerobic conditions. This highlighted the need for improved techniques to accelerate biodegradation. Then in 2012, co-composting experiments using high-organic-value manure were carried out to enhance hydrocarbon bioavailability and increase biodegradation temperatures.

The project team included the following:

  • Dow Chemical Canada ULC – Audrey Sidebottom, Remediation Leader and Joanne West, Technology Leader.
  • Petromont – Louis Rail, President and Jean Carpentier, Vice-President.
  • WSP Golder: Jimmy Côté, ing. M.Sc. – Project Director; Kevin Barrest, P.Eng., M.Eng, PMP. – Project Manager; Christian Gosselin, ing., M.Ing. – Site Rehabilitation Specialist; and Denis Duhamel, M.Sc. – Environmental Specialist.

“WSP was involved from the beginning and responsible for all facets of the project spanning a period of more than a decade,” recalls Barrest. “This included the site assessment, pilot testing, interfacing with the governing bodies, design and fabrication of the treatment units, construction of the biopile platforms and managing site operations including all civil works.”

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Following extensive experimentation, the project team embarked on the full-scale biopiling treatment. They identified organic amendments, structuring agents, and the use of surfactants to mobilize PAHs as key factors in enhancing degradation rates. A co-composting system was formed from biopiles built atop an impermeable lined base that was covered with a liner to regulate temperature and optimize contaminant recovery.

To monitor the progress of the treatment, the project team introduced real-time biopile treatment monitoring using telemetry and tablets. This technological advancement provided essential insights and confirmed that the implemented solutions were yielding results.

View from inside the treatment unit. (Credit: WSP.)

Overcoming remediation challenges

“This project did not lack challenges, from the initial characterization which posed significant hurdles and effort given the size of the site and its complex history, to developing a treatment process for highly impacted soil with varying combinations of contaminants and making that strategy work on a large scale,” explains Barrest.

“But given the extended timeline of the program, the team had the opportunity to continually improve the treatment process over subsequent operating seasons to account for persistent contaminants and reduce project consumables, such as filter media for water or air treatment or amendments utilized within the soil treatment process to further reduce our environmental footprint.”

Ensuring environmental preservation, the project implemented protection procedures for endangered species and adopted measures to mitigate potential impacts near wetlands. Additionally, the team utilized the GoldSET tool to conduct a comprehensive analysis, enabling the identification of the most sustainable remediation plan considering environmental, social, and economic factors.

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GoldSET, developed by Golder Associates, is an innovative web-based toolset that optimizes sustainability in project management by evaluating alternatives and monitoring ongoing projects using geospatial, qualitative, and quantitative data. It enables the integration of triple-bottom-line considerations and promotes proactive stakeholder engagement.

Project completion and impact for the industry

After 10 years in the works, the project was completed in 2022, and celebrated the successful treatment of 190,000 cubic meters of soils through biopiling and its successful removal of contaminants from the site. The application of rhizodegradation to 35,000 cubic meters of soil and the on-site management of 18,000 cubic meters of metal-contaminated soil exemplified the project’s comprehensive approach to risk analysis and mitigation.

View of the soil before (left) and after rhizodegradation showing soil destructuration (right). (Credit: WSP.)

This project was a memorable one for Barrest and the entire project team.

“Aside from the obvious technical and sustainability aspects applicable to complex sites, this project has allowed an entire cohort of young environmental professionals to cut their teeth and gain valuable real-world experience that has benefited a multitude of organizations, both in the public and private sectors,” remarks Barrest.

“One aspect that was particularly special about this project was the way in which the team was fully integrated, working hand in hand with our clients and sharing the challenges and wins. This approach gave everyone involved a sense of ownership, the ability to become personally invested in the project and frankly proud to be part of the team.  This personal touch is echoed by the overall success of this project.”

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The Dow-Petromont rehabilitation project serves as a testament to the power of collaboration, technological innovation, and sustainable remediation in addressing environmental challenges. Through experiments, real-time monitoring, and a comprehensive approach to risk management, the project team transformed a brownfield into an environmental success story. With its forward-thinking approach and vision for future redevelopment, this 2022 Brownie Awards winner stands alongside one of many other remarkable and committed project award recipients.

Do you know of an award-worthy brownfield project or project leader? Be sure to submit your nomination for the 2023 Brownie Awards by September 18th. For further information on the Brownie Award categories and past award winners, please visit:

Claire Latham, honour roll student and multimedia storyteller in the making, is entering her third year of the Media Information and Technoculture program at Western University. 


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