Environmental remediation of the former Pétromont site

Varennes, Québec

Englobe was tasked with the decontamination of the site surrounding

the former Pétromont petrochemical plant in Varennes. Between 2014

and 2024, Englobe treated 701,665 m

3

of contaminated soil and fully

rehabilitated this 85,000 m

2

site — one of the largest projects of its kind in

Québec history.

To achieve this, Englobe used biopiles, a unique and innovative

technological and design approach based on onsite treatment using

indigenous microorganisms and in-house-developed water, air and soil

treatment technologies. Essentially, biopiles is a biological oxidation

treatment technique in which indigenous fungi and bacteria are grown

onsite through a precise calibration of parameters (humidity, PH, nutrients

and more), and then encouraged to feed on the various contaminants

present in the soil.

This method signif icantly reduced the project’s environmental footprint

and resource use. The onsite treatment of nearly 1.2 million tonnes of soil,

drawn from an area the size of 88 football f ields, resulted in nearly 32,900

fewer semi-trailer truck trips for contaminated soil disposal and backf ill

soil delivery. As a result, only 4,000 metric tonnes of soil – less than 1%

of the total volume treated — were transported of f-site for appropriate

disposal. A secondary benef it to this approach was a considerable

reduction in transportation-related nuisances such as noise, dust and

traf f ic, which helped protect the quality of life for residents.

Inspired by circular economy tenets, Englobe also reused the concrete

recovered during excavation to f ill the project’s construction needs, and

leveraged water treatment technologies to eliminate the need for an

external water supply. These measures resulted in considerable cost

savings for the project and a marked reduction in resource use.

Recipient of the 2025 Canadian Consulting Engineering

Excellence Award

Introduction Environment Social Governance Appendix

23

Environmental remediation

ELEVATING CLIENT COLLABORATIONS – Sustainable service of ferings

Varennes, Québec

Learn more about this project.