Areas of expertise Site Remediation

Sanexen’s mission is to assist companies and organizations dealing with contamination issues to determine and find the most cost-effective solutions that are best adapted to their needs.

Although environmental issues are often complex, our scientists and specialists remain up to date on new investigation and remediation methods and are therefore able to adequately meet clients’ specific needs while adhering to the most stringent environmental regulations.

Sanexen works closely with residential, commercial and industrial developers, as well as with engineers and architects involved in land planning and development. Through partnerships of this nature, we are able to perform environmental studies and prepare site remediation strategies that significantly reduce the risks associated with a property’s environmental liabilities.

Sanexen’s Site Remediation Department implements specific water, soil, sediment and residue treatment measures on client properties.


FeuilleEnvironmental Site AssessmentsFeuilleRemediation based on Risk AssessmentFeuilleIn Situ TreatmentFeuilleBuilding DecontaminationFeuilleWater TreatmentFeuilleTurnkey DecontaminationFeuilleBiopile - Soil Treatment

Environmental Site Assessments

Sanexen conducts Phase I and II environmental site assessments on industrial, commercial and residential sites. These types of studies are designed to create a portrait of the environmental situation for a specific site or activity at any given time.

In order to depict the most accurate portrait possible, our experts use a variety of techniques and methods:

  • Environmental site assessments (Phase I and II)

  • Expert certifications (Division IV.2.1 of the EQA)

  • Hydrogeological studies and modelling

  • Waste classification

The data collected , during the environmental assessments is used as a basis for the elaboration of the decontamination strategy and to establish the cost of the work. 

Sanexen also offers support for the obtention of environmental authorizations and permits (e.g.: MELCCFP, municipal, etc.), as well as the review of environmental aspects as related to the sale or acquisition of a property

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Remediation based on Risk Assessment

Sanexen, a recognized leader in the area of toxicological risk assessment, has performed a large number of remediation projects on this basis.

In Quebec, the Environment Quality Act specifies provisions regarding the management of contaminated properties based on the risk assessment approach. By limiting the decontamination work to the areas presenting a risk to human health or the environment, this approach often leads to the re-use of contaminated sites which, due to prohibitive costs, may not otherwise be remediated. Similar legislation exists in other provinces and states around the world.

Risk assessment is part of an environmental management process based on risks. The advantages of this approach are numerous:

  • Risk assessment addresses site-specific conditions; these conditions can greatly influence the risks to which persons or living organisms are exposed;
  • Risk assessment identifies real risks arising from contamination, even when no standards (criteria or guideline) for a given substance or pathogenic agent exist; accordingly, this approach is often safer than using arbitrary generic standards;
  • Risk-based management is often considerably less expensive than the more traditional approach based on meeting generic standards.

Multiple solutions for brownfields, urban fringes and industrial site redevelopment have thereby been devised, thus rendering large-scale residential development projects and recreational or commercial urban planning development economically viable.

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In Situ Treatment

Sanexen has conducted a large number of in situ remediation projects using several proven and innovative technologies.

Among the various projects completed by Sanexen, certain issues have involved R&D aspects – an area for which Sanexen is renowned.

Most in situ projects are highly technical in nature and call for in-depth knowledge of the discipline in question. Sanexen's personnel have a solid experience in the development of remediation strategies and the implementation of proven and efficient treatment systems. The technical approach leads to the attainment of the established remediation objectives within pre-set financial parameters and timetables.

The following is a partial list of treatment processes used:

  • Chemical oxidation of petroleum hydrocarbons
  • Elimination of gasoline by forced aeration (sparging), extraction of volatile compounds and catalytic oxidation
  • Injection of a bacterial consortium in coarse-grained soils contaminated by light hydrocarbons
  • Steam injection and multi-phase extraction to remove heavy fuel oil from fractured rock
  • Recovery by pumping chlorinated solvents in the form of dense non-aqueous phase liquids (DNAPL), including the installation of a Waterloo-type barrier – the largest DNAPL project performed in Canada to date
  • Multi-phase extraction and in situ biotreatment to eliminate furnace fuel oil, at a depth of 20 meters, in a dense urban area
  • Washing of coarse-grained soils by warm water circulation to remove hydrocarbons and metals
  • Volatilization and extraction of PCEs present as DNAPL beneath a building
  • Controlling off-site migration of heavier-than-water contaminants (TCE, DCE) by pumping, treatment and injection of additives to create conditions favourable to contaminant biodegradation
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Building Decontamination

Environmental decontamination in buildings requires a thorough knowledge of characterization methods as well as decontamination processes that can be used on various matter such as concrete, wood and metallic finishes.

Sanexen has carried out numerous decontamination projects, for both Canadian companies and government organizations, involving waste segregation, the use of innovative clean-up procedures, dismantling contaminated equipment and off-site management of recyclable materials and waste.

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Water Treatment

Sanexen designs, builds and operates treatment units for ground, run-off, wash and process water. They possess several mobile units capable of functioning at flow rates varying from 20 to 5,000 L/min.

ULTRASORPTION®, developed by Sanexen, who holds exclusive rights to this recognized process, enables the removal of toxic organic compounds (including PAHs, PCPs, PCBs, PCDDs and PCDFs) from water. Since 1985, this process has been used successfully in a wide variety of projects to treat millions of litres of contaminated water.

Sanexen also adapts these units to treat other types of contaminants such as surfactants, solvents, petroleum products (diesel fuel, oil, gasoline and grease), acids, metals, etc.

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Turnkey Decontamination

Sanexen also manages turnkey-type remediation projects for its clients. This approach facilitates project planning eliminating uncertainties during diverse remediation.

Our professionals are able to assist clients in all phases of project analysis and to implement remediation strategies that attain the desired technical objectives while taking into account the most advantageous cost/benefit factors.

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Biopile - Soil Treatment

Sanexen uses biopile technology to reduce hydrocarbon concentrations in excavated soils. More than 1,000,000 metric tonnes of soils have been successfully treated using this method, at times in challenging conditions such as those in Northern Canada. Biopile technology has proven highly instrumental in achieving optimal cost-effectiveness.

Biopile technology

This technology draws on aerobic biodegradation to form treatment piles or “cells”, stimulating the microbial content already present in the soils. Stimulation is accomplished by increasing moisture and adding nutrients such as nitrogen and phosphorous to the soils. Through aerobic microbial activity, petroleum-based compounds adsorbed in soil particles are broken down, reducing their concentrations.

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