Environmental characterization (phase ll, phase lll and additional diagnostics)
When actual contamination risks are identified by a Phase I (historical study and site visit to determine if potentially polluting activities have occurred on the site), the presence of contaminants is confirmed by a Phase II, and their extent is delineated by a Phase III.
Phases II and III of environmental characterization are key stages in the environmental assessment of a site.
Indeed, they allow:
- Determining if contaminants are present, where, in which concentrations, and how far they may have spread in the environment.
- Understanding potential risks to human health and the environment.
- Defining remediation solutions adapted to the context.
- Estimating the budget for the envisaged rehabilitation works.
Phase II involves sampling of soil, groundwater, and other materials (fill, waste materials, sediments, sludges, etc.) collected for laboratory analysis to determine the presence and concentration of potentially hazardous contaminants. If Phase II confirms the presence of contaminants, it may be sufficient to plan remediation works, or it may need to be complemented by a Phase III.
Phase III involves more targeted sampling to determine the horizontal and vertical extent of contamination, which then allows for the identification of remediation solutions adapted to the context and their evaluation against each other.
Several factors are taken into consideration to determine the most appropriate remediation method, including the site geology and hydrogeology, the nature of contaminants and their concentration levels, the volumes of soils involved, site accessibility, time and space constraints, cost of works, access to water and energy, available technologies, pollution generated by the works, neighborhood acceptability of treatment, etc.
For each of Phases II and III, the methodology proposed by VALGO Environment will be as follows:
- Localisation of infrastructures
- Elaboration of sampling strategy
- Sampling of soil, groundwater, and other materials (fill, waste materials, sediments, sludges, etc.)
- Laboratory analysis of samples
- Data interpretation
- Production of a report including a table summarizing the results of laboratory analysis and recommendations for further actions.
Engineering – Custom Solutions
We have an in-house team of engineers specializing in various disciplines (geology, geophysics, hydrogeology, microbiology, chemistry, process engineering, etc.).
In addition, to support our operational teams, we have an internal laboratory that allows us to:
- Analyze the feasibility of a remediation technique for soil, groundwater, or other materials (fill, waste materials, sediments, sludges, etc.).
- Determine the conditions for the implementation of the techniques whose feasibility has been proven.
These skills and know-how enable VALGO Environment to offer its clients expertise in on-site or in situ soil remediation solutions, which are more environmentally-friendly and cost-effective.
In addition to our expertise, we have a geophysical department whose aim is to develop the application of geophysics to contaminated sites and soils. This department also conducts pyrotechnical diagnostics.
All of these competencies allow us to cover the entire value chain of contaminated site remediation, from its characterization to the completion of works, from design to implementation.
Sites rehabilitation (phase lV)
When contamination levels exceed the applicable criteria for the site, environmental rehabilitation works are necessary. This step corresponds to Phase IV of a remediation project
VALGO Environment has the expertise to design and carry out remediation works aimed at restoring the environmental quality of the site in accordance with zoning regulations and the current or intended use of the site.
The works we offer are always based on the results of environmental characterizations (Phases II and III) and comply with regulations and government guidelines. But most of all, they are also tailored to each situation, taking into account site-specific constraints and client needs.
Contaminated soils can be excavated for off-site disposal, treated on-site, or left in place and treated in situ.
For Phase IV, the methodology followed by VALGO Environment will be as follows:
- Initial assessment (analysis of phase I to III)
- Development of the rehabilitation plan
- Planning
- Remediation
- Sampling to control the site meets the requirements
- Laboratory analysis
- Data interpretation
- Preparation of the rehabilitation report
In Situ Remediation
In situ techniques are applied directly into the soil and/or the groundwater to treat contaminants. They do not require excavation. They involve biological, chemical, physical, mechanical, thermal processes, or a combination of these methods.
The in situ remediation solution offered must be tailored to the site and therefore must be established by experts.
The advantages of in situ remediation are numerous:
- Avoids excavation costs
- Avoids soil transportation costs
- Reduces greenhouse gas emissions
- Minimizes site restoration works
- Limits atmospheric dispersion of contaminants
- Addresses contamination issues in depth and large volume
- Avoids soil landfilling, making it a sustainable option as well as an option to be preferred in light of the directives issued by the MELCCFP.
On-Site Remediation
On-site techniques are applied onto excavated soil or groundwater that has been pumped out to treat contaminants. They require excavation but do not require transportation off-site. Like in situ techniques, they involve biological, chemical, physical, mechanical, thermal processes, or a combination of these methods. Each corresponds to a variation of an in situ technique.
On-site treatments avoid soil transportation and are therefore advantageous economically and environmentally (reducing greenhouse gas emissions). On-site remediation also avoids soil landfilling, making it a sustainable option as well as an option to be preferred in light of the directives issued by the MELCCFP.
Off-Site Remediation
Off-site remediation involves the excavation of soils followed by their transportation off-site to a disposal facility, which may either bury or treat them.
Soil Traceability
Since January 1, 2023, all contaminated soils transported off the original site must be tracked through the government traceability system Traces Québec*, in accordance with the Regulation concerning the traceability of excavated contaminated soils (RCTSCE).
Soil traceability involves tracking their movement from the excavation site to their final destination.
VALGO Environment offers its clients the assurance of tracking the evacuation of contaminated soils. This includes opening the project and entering the data on Trace Québec’s Attestra* platform, providing and managing mandatory transport manifests, and collecting official weigh bills to prove that the soil was disposed at authorized centers.
Soil Disposal
For off-site management of contaminated soils, VALGO Environment prioritizes treatment centers. Among them is Enfoui-bec, a company owned by the VALGO Canada group. Their biological treatment platform is a fast, sustainable, and affordable solution for soils containing biodegradable contaminants, making them a preferred partner. VALGO Environment also collaborates with landfill sites such as Gestion 3LB, another subsidiary of VALGO Canada group.
Consult our treatment techniques
Effluent treatment
Whether for industrial clients or construction contractors, VALGO Environment offers mobile effluent treatment solutions.
- Sampling of effluents to be treated for laboratory analysis,
- Analysis of the results and sizing of a water treatment line to meet discharge criteria,
- Supply, mobilization, operation, and maintenance of the mobile treatment system, including control sampling,
- Demobilization of the system and management of waste materials generated during the treatment (sediments, saturated activated carbon, etc.).
Management of sludge and sediments
The sludge generated by industrial processes can accumulate until it is necessary to dredge the basins or lagoons where they settle. Similarly, sediments carried by currents can limit or obstruct navigation and water flow, requiring dredging.
VALGO Environment offers a turnkey service for these sludge and sediment management, whether contaminated or not. It may include:
- Dredging of sludge or sediments (hydraulic or mechanical)
- Cleaning of basins or lagoons
- Particle size sorting in cases where the contamination is linked to particles of a certain size, they are then isolated to valorize the other particles
- Coagulation-flocculation of the fine particles
- Dewatering of the fine particles
- Treatment or pre-treatment of the various granulometry.
Waste Management
In some cases, for industrial by-products that do not find acceptance among accessible disposal facilities, VALGO Environment can develop treatment or pre-treatment processes to lower the levels of concentrations of problematic contaminants so that they comply with the requirements of these facilities.
To this end, VALGO Environment calls on its internal laboratory, which will use a sample of the residue to:
- Analyze the feasibility of a treatment or pre-treatment for the waste.
- Determine the conditions for the implementation of the techniques whose feasibility has been proven.
OUR TREATMENT TECHNIQUES
Biopile
Pile the soil to create a solid biological reactor, in which the biodegradation conditions are optimized (air, nutrients, moisture…)
Chemical Oxidation or Reduction
Injecting a reagent into groundwater that will destroy contaminants or transform them into a less toxic form.
Coagulation-Flocculation
Putting into contact suspended solids (SS) with a coagulant and/or a flocculant to facilitate the settling or separation of SS in an effluent.
Dehydration
Reducing the water content of sludge or sediments using filter bags, a filter press, or a centrifuge.
Dredging
Extracting sludge or sediments deposited at the bottom of a watercourse, water reservoir, or structure that remains submerged.
Excavation of Polluted Soils and Evacuation for Disposal
Excavating with an excavator to extract contaminated soils and subsequently evacuating them to suitable disposal facilities.
Granulometric Separation
Sorting soil fractions based on their diameter (gravel, sand, silt, fines). This technique is used in cases where contamination is linked to one of the fractions, allowing the other fractions to be valorized.
Hydraulic Confinement
Creating a depression by pumping to prevent contaminated water from migrating.
Hydraulic Excavation
Soil suction using a vacuum truck after liquefying them with a water lance.
Lagoon Cleansing
Emptying the lagoons of their contents (effluents, sludge, and sediments) and cleaning their walls.
Landfarming
Activate the microbiological functioning of the soil with agricultural techniques and machines. This technique is very easy to implement but takes up spaces.
Multiphase Extraction
Aspirating up to 3 phases containing contaminants (vapor phase, dissolved phase, and pure phase) for treatment at the surface in specialized equipment.
Permeable Reactive Barrier
Installing a permeable reactive material in a trench excavated in the soil, which will treat dissolved contaminants in groundwater as they flow through it, upon contact with the reactive material.
Physical Confinement
Installing an impermeable barrier to isolate the contaminated soil, preventing the spread of contamination and its contact with the exterior.
Pneumatic Excavation
Soil suction using a vacuum truck after loosening them with a compressed air lance. This technique is only applicable to loosely compacted soils.
Pumping and Treatment
Pumping the water to an on-site treatment unit. Pollutants dissolved in groundwater are extracted from the water through physical, chemical, or biological processes.
Pumping-Skimming
Pumping the pollution floating on the surface of groundwater.
Punctual Excavation with an Auger
Excavating a localized contamination using a mechanical auger. This technique is often used when excavations are located near a building or an infrastructure whose stability would be threatened by conventional excavation methods.
Soil Flushing
Injecting air into the water table to extract dissolved pollutants. This technique is coupled with venting to prevent pushing the pollutant into the atmosphere.
Soil Leaching
Generating water circulation (often supplemented by surfactants) in the soil to extract leachable contamination. The water is then pumped and treated on-site in a suitable unit.
Soil Vapor Extraction
Generating an air circulation in the soil to extract volatile contamination, similar to airing out a room where paint is used, except here the vapors are directed to a vapor treatment system.
Soil Washing
Vigorously stir the soil in a liquid (generally water), and then separate the liquid, to pull different pollutants out of the solid matrix.
Solidification / Stabilization
Incorporating a hydraulic binder or reagent to prevent the migration of contamination, either by physically trapping it in a solid and low-permeability matrix, or by changing the speciation of the contaminant to make it less mobile.
Thermal Desorption In-Situ
Installing heating devices in the soil to volatilize contaminants, which are then aspirated through a network of soil vapor extraction.
Thermopile
Pile the soil, to heat it up and vaporize the contaminants which are then trapped in downstream equipment (condensers, filters…)
Treatment or Pre-Treatment of the Finest Fractions
Treating the dehydrated sludge or sediments to meet the acceptance criteria of a disposal center.