Thermal Remediation

Thermal remediation that permanently destroys the contaminant on site.

Nelson designs and operates one of the largest mobile thermal remediation fleets in the industry. We treat soil, sediment, and groundwater contaminated with PFAS, dioxins, PCBs, hydrocarbons, and other persistent organics, and we destroy the contaminant rather than transferring it to a landfill.

What is thermal remediation

Heat does what biology and chemistry can't.

Thermal remediation is the controlled application of heat to remove or destroy contaminants in soil, sediment, and groundwater. At low to moderate temperatures, contaminants volatilize out of the matrix and are captured for treatment. At sustained high temperatures, the contaminants are molecularly destroyed in a secondary combustion chamber.

Two delivery modes are used in practice. Ex-situ thermal remediation excavates the contaminated material and feeds it through a mobile rotary thermal desorption unit on the site. In-situ thermal remediation heats the contaminated zone in place using electrical resistance heating, thermal conduction heating, or steam injection. Both produce the same outcome: contaminant gone, soil returned to the site.

TechnologyThermal desorptionDirect-fired and indirect-fired systems, temperature bands by contaminant, moisture limits, and how throughput is set.

TechnologyThermal oxidiser systemsBurner design, chamber temperature and residence time, and how destruction-and-removal efficiency is verified.

When thermal is the right remedy

Thermal remediation is the preferred treatment when:

The contaminant resists biological or chemical treatmentPFAS, dioxins, furans, PCBs, weathered hydrocarbons, creosote, pesticides, and explosives are persistent by design. Thermal destruction is one of the few remedies that breaks them at the molecular level.

Closure timelines are tightBioremediation runs on geological time. A mobile thermal desorption unit can treat tens to hundreds of tonnes per day, compressing multi-year remediation schedules into months.

Off-site disposal is restricted or impracticalWhen landfill disposal is restricted by regulation (PFAS, dioxins), prohibited by community agreement, or made uneconomic by haul distance, on-site thermal destruction eliminates the off-site liability entirely.

Contamination is deep, mixed, or heterogeneousIn-situ thermal heats the entire treatment volume regardless of geology, NAPL phase, or contaminant mixture. Pump-and-treat and chemical injection cannot match that uniformity.

The remedy must be permanent and verifiableDestruction-and-removal efficiency (DRE) is measured in real time and submitted to the regulator. There is no monitoring tail, no institutional control, no risk of contaminant rebound.

Our mobile thermal fleet

Mobile thermal desorption units designed for permanent destruction.

Nelson's RS-Series mobile thermal remediation systems are engineered for on-site deployment in the Canadian Arctic, tropical equatorial sites, and everything in between. Each unit pairs a counter-flow rotary thermal desorber with a high-temperature secondary combustion chamber, quench, and baghouse, the complete chain required to convert desorption into permanent destruction.

Throughput ranges from 5 tonnes per hour for surgical treatment of small-volume, high-concentration sites to over 45 tonnes per hour for large-scale remediation programs. Continuous emissions monitoring (CEMS) feeds the regulator's closeout package directly.

See the full mobile fleet and process flow

Thermal remediation in the field

Selected projects.

Bear Hills, Alberta, Top 25 Remediation ProjectMobile thermal desorption of weathered hydrocarbon impacted soil. Treated material returned to the site as engineered fill, with revegetation inside a single growing season.

Tioga, North Dakota, Anatomy of a Cleanup1.2 million tonne pipeline release. Mobile thermal remediation deployed at scale, with verified DRE and complete on-site closure.

Vietnam, Legacy dioxin destructionIndirect thermal desorption applied to legacy dioxin residues. One of the few thermal programs ever executed at this scale in Southeast Asia.

NATO PFAS, Mobile high-temperature destructionSelected by NATO for PFAS-impacted military-base remediation. Mobile thermal destruction sized to AFFF-driven contamination profiles.

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Frequently asked

What is thermal remediation?

Thermal remediation is the use of controlled heat to remove or destroy contaminants in soil, sediment, or groundwater. At low to moderate temperatures, contaminants are volatilized and captured for treatment (thermal desorption). At sustained high temperatures, the contaminants are molecularly destroyed in a secondary combustion chamber. The treated soil is returned to the site as engineered fill, eliminating the liability of haul-and-dispose.

When should thermal remediation be used?

Thermal remediation is the preferred remedy for persistent organic contaminants that resist biological or chemical treatment, including PFAS, dioxins, PCBs, weathered hydrocarbons, creosote, pesticides, and explosives. It is also the right choice when site closure timelines are tight, when contamination is deep or heterogeneous, or when off-site disposal is restricted by regulation or distance.

How is in-situ thermal remediation different from ex-situ?

In-situ thermal remediation heats contaminated soil and groundwater in place, using electrical resistance heating, thermal conduction heating, or steam injection. Ex-situ thermal remediation excavates the soil and treats it through a mobile rotary kiln or thermal desorption unit at a staging area on the site. The choice depends on contaminant depth, building obstructions, and target cleanup levels.

What contaminants can thermal remediation destroy?

Nelson's thermal systems treat the full spectrum of persistent contaminants: PFAS (per- and polyfluoroalkyl substances), dioxins and furans, PCBs, polycyclic aromatic hydrocarbons (PAHs), petroleum hydrocarbons (gasoline through weathered crude), BTEX, chlorinated solvents, creosote, pesticides, and explosives. Treatment temperature and residence time are tuned per contaminant.

Is thermal remediation recognized by regulators?

Yes. High-temperature thermal destruction is identified as Best Available Technique (BAT) under the EU Industrial Emissions Directive and as a preferred treatment for persistent organic pollutants under the Stockholm Convention. The U.S. EPA, Environment and Climate Change Canada, and provincial regulators (Alberta, BC, Saskatchewan, Ontario) accept thermal remediation closure packages backed by destruction-and-removal-efficiency (DRE) verification.

How much does thermal remediation cost?

Unit cost depends on contaminant type, soil moisture, throughput, and site logistics. Permanent on-site destruction is typically competitive with, and often less expensive than, long-haul disposal once transport, landfill liability, and regulatory tail-risk are factored in. Nelson provides site-specific pricing after a no-cost feasibility review.

Capabilities, full mobile fleet & process

In-Situ Thermal Remediation

Thermal Soil Remediation

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