Why Now is the Right Time to Consider Thermal Remediation for Your Site

For decades, environmental consultants and engineers have sought a remediation technology that safely delivers predictable, high-success outcomes across a wide range of sites from simple to complex and for a wide range of contaminants. With over 750 projects successfully completed worldwide, thermal remediation has consistently demonstrated its ability to clean up contaminant source zones, above and below the water table, in silts, sands, clays and even fractured bedrock, and at sites with both low and high permeability and groundwater flux zones. 

But what makes this technology so reliable? And what factors determine whether it’s the right fit for your contaminated site? 

This blog explores how thermal remediation works, the factors that contribute to its high success rate, and why it continues to be a preferred solution for complex remediation projects. 

Why Thermal Remediation Works

Success in environmental remediation is defined by meeting project scope and cleanup objectives, whether that means achieving regulatory standards, securing site closure, or ensuring long-term environmental safety. Thermal remediation stands out due to its ability to reliably remove volatile and semi-volatile organic compounds (VOCs and SVOCs), including chlorinated solvents, PAHs, PCBs, dioxins, creosote/coal tar, and even PFAS. 

The fundamental mechanism behind thermal remediation is the application of heat to the subsurface, which either mobilizes contaminants by volatilizing them and converting them into a recoverable gas phase or results in degradation and destruction of the contaminants. For the volatilization mechanism, once contaminants are in the vapor form, they are extracted from the subsurface through a vapor recovery system and treated using a variety of vapor-phase sorption and destruction technologies, thus ensuring complete removal. For destructive mechanisms, the contaminants can be completely mineralized to H2O, CO2, and CO or partially degraded to form shorter chained, more volatile compounds that are removed in the vapor phase and extracted for treatment.   

Additionally, thermal remediation is known for its: 

• Versatility – Effective across a wide range of contaminants and geological conditions, including fractured rock and low-permeability soils. 
• Predictability – The technology has been applied to hundreds of sites with consistently successful outcomes. 

Key Factors That Influence Viability

To ensure its high success rate, several factors that influence the effectiveness of thermal remediation need to be considered during the design and implementation phases: 

Site Conditions 

• Geology and Hydrogeology – Thermal remediation can be applied in sands, silts, clays, and fractured rock. However, permeability plays a key role in determining the best thermal technology. 
• Groundwater Flow – Sites with high groundwater velocity (greater than one foot per day) may require additional hydraulic control, such as multi-phase extraction wells or physical barriers (sheet pile or slurry walls), and/or the use of Steam Enhanced Extraction (SEE, a combination of steam injection and aggressive groundwater and vapor extraction to maintain pneumatic and hydraulic control). 

Contaminant Type and Concentration 

Thermal remediation is highly effective for VOCs, SVOCs, PAHs, PCBs, dioxins, petroleum hydrocarbons, creosote and coal tars, and even mercury and PFAS. 

However, different contaminants require different heating targets: 

• VOCs (e.g., chlorinated solvents): ~100°C (boiling point of water) 
• PCBs, PAHs, and dioxins: 300–400°C 
• PFAS and mercury: 350–450°C 

Some contaminants undergo co-boiling, which lowers the temperature required for effective volatilization, accelerating the cleanup process.  For example, PCE DNAPL will boil at 87°C when in contact with water, whereas PCE in a beaker by itself boils at 121°C. The co-boiling mechanism means that heating a site to 100°C will result in the effective removal of any DNAPL and the dissolved and sorbed phases of the contaminants, resulting in the effective remediation of recalcitrant contaminant source zones.  

Technology Selection & Implementation 

Thermal remediation includes three primary technologies, each suited to different site conditions: 

• Thermal Conduction Heating (TCH) – Uses heating elements to distribute heat through conduction, which is effective above and below the water table and in the full range of soil types including fractured rock. 
• Electrical Resistance Heating (ERH) – Applies alternating current through electrodes to heat soil. Current flow is dependent on the presence of water, so it is best for sites with moist soils and where the treatment zone is primarily below the water table. 
• Steam Enhanced Extraction (SEE) – Injects steam to heat high-permeability zones and accelerate contaminant removal. SEE is a good choice for sites with high groundwater flux zones. 

At complex sites, multiple technologies can be combined to ensure complete treatment. For example, at sites with low to moderate groundwater flux zones and high groundwater flux zones, TCH or ERH can be combined with SEE to effective heat and treat the site.  

Structural and Utility Considerations 

• Beneath Buildings & Utilities: Thermal remediation can be applied under active buildings (e.g., dry cleaner sites in strip malls or manufacturing facilities) using protective measures like insulation and cooling loops to protect underground utilities and angled drilling to address access limitations and avoid disrupting foundations. 
• Geotechnical Considerations: Proper technology selection and system design can address most geotechnical concerns and mitigate any impacts to structures and utilities due to settlement. Proper characterization of subsurface geotechnical properties is a prerequisite for addressing geotechnical concerns. 

Why Thermal Remediation is Gaining Adoption 

Thermal remediation is not just a niche technology—it has become a widely recognized approach for addressing high-mass contamination sites and Superfund projects: 

• Over 10% of all in-situ Superfund remedies (2018–2020) included thermal remediation.(U.S. EPA, 2023) 
• As of 2023, around 20 Superfund sites have undergone treatment with thermal technologies. (U.S. EPA, 2023) 
• It is estimated that over 750 sites have been treated using thermal remediation as of 2025, and that 25 to 30 sites are currently being treated each year. 

With its proven success rate and ability to handle complex contamination challenges, thermal remediation continues to be a preferred solution for environmental consultants, project managers, and engineers. Whether targeting chlorinated solvents, PAHs, or even emerging contaminants like PFAS, this technology provides a comprehensive, predictable, and highly effective approach to site remediation. 

If you’re considering thermal remediation for your site, partnering with experienced professionals can help ensure the best possible outcome. 

Want to see if thermal remediation is the right fit for your site? Our experts can help assess feasibility and guide you through the process. Let’s talk! 

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