Halogenated VOC, Refrigerant & Fumigant Remediation Services
What Are Halogenated VOCs, Refrigerants, and Fumigants, and Why Are They a Problem?
Halogenated volatile organic compounds are synthetic chemicals containing chlorine, bromine, fluorine, or another halogen. This broad group includes chlorofluorocarbons, hydrochlorofluorocarbons, hydrofluorocarbons, brominated fumigants such as 1,2-dibromoethane (EDB), and other solvents, refrigerants, aerosol propellants, and specialty chemicals.
Many halogenated VOCs are mobile in soil and groundwater and can persist for decades. Depending on the compound and release, they may dissolve into groundwater, partition into soil gas, sorb to soil, or occur as non-aqueous phase liquid. These sources can create long-term groundwater and vapor-intrusion risks. Some refrigerants also have high global-warming potential, creating concerns beyond site cleanup.
Common Sites with Halogenated VOC, Refrigerant, and Fumigant Contamination
- Refrigerant, aerosol, and chemical-manufacturing facilities
- Cold-storage and industrial refrigeration operations
- Agricultural fumigant formulation, storage, and application areas
- Fire-suppression manufacturing and testing facilities
- Solvent-handling, degreasing, and industrial cleaning operations
- Burn pits, disposal areas, leach fields, and historical waste sites
Thermal Remediation: A Reliable Solution for Halogenated VOC Source Zones
In situ thermal remediation applies heat directly to contaminated soil, groundwater, and rock to accelerate the physical, chemical, and biological processes that remove or destroy halogenated VOCs. Unlike extraction systems alone, thermal treatment can address concentrated sources and contaminant mass stored in low-permeability soils or fractured rock.
TerraTherm selects the treatment temperature according to the contaminant chemistry and cleanup objective. Volatile halogenated compounds and non-aqueous phase liquid can be removed near the boiling point of water, while susceptible compounds such as EDB may be destroyed through thermally enhanced hydrolysis at lower temperatures. Gentle heating can also support biological degradation where the site and contaminant mixture are amenable.
100°C Treatment: Volatilization and Co-Boiling
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Heating to the boiling point of water increases contaminant vapor pressure and mass-transfer rates. Generated steam strips halogenated VOCs from soil and groundwater and transports them toward extraction wells. Where non-aqueous phase liquid is present, co-boiling with water can rapidly transfer contaminants from an immobile liquid phase into a recoverable vapor stream. Recovered vapor, water, and mobile product are separated and treated aboveground.
Thermal treatment is commonly focused on the source zone, where concentrations and mass are highest. Lower-concentration plume areas may then be addressed through a treatment train with biological, chemical, hydraulic, or monitored attenuation approaches. Required energy and operating duration depend on contaminant properties, cleanup goals, soil moisture and organic carbon, groundwater flow, treatment depth, co-contaminants, and heat losses.
Moderate-Temperature Treatment: Thermally Enhanced Hydrolysis
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For susceptible halogenated VOCs, hydrolysis can proceed much faster as temperature increases. EDB is a primary example. Where site-specific kinetics confirm amenability, controlled heating below the boiling point of water can accelerate in situ destruction without relying on volatilization as the primary treatment mechanism.
The treatment design must evaluate reaction kinetics, water chemistry, transformation products, starting mass, and cleanup goals. Vapor control, monitoring, and extraction requirements remain site-specific. After heat-up, less power is generally required to maintain temperature, and below-grade installations may preserve access in active facilities and transportation corridors.
Low-Temperature Treatment: Thermally Enhanced Bioremediation
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Gentle heating can increase biological reaction rates, improve amendment distribution, and increase contaminant availability. Low-profile heaters can warm the target interval while amendments are delivered through nearby or shared installation locations. The optimum temperature depends on the microbial community, amendment system, geochemistry, and target compounds, so performance criteria are established through site-specific testing and monitoring.
Our Heating Solutions for Halogenated VOCs, Refrigerants, and Fumigants
Electrical Resistance Heating (ERH)
ERH passes alternating electrical current through moist soil and groundwater between electrodes. Electrical resistance converts energy to heat within the treatment zone. ERH can support boiling-point removal, thermally enhanced hydrolysis, and low-temperature biological treatment where adequate moisture and electrical conductivity are present.
A robust design evaluates electrical resistivity, moisture, groundwater flow, electrode spacing, and balanced power delivery. Vapor extraction is used for boiling-point treatment, and multiphase extraction may be added where groundwater flow or mobile product requires hydraulic control and liquid recovery.
Thermal Conduction Heating (TCH)
TCH transfers heat from subsurface heaters into surrounding soil and rock by conduction. Because it does not depend on formation moisture or electrical current flowing through the subsurface, TCH can be applied in wet or dry soil and fractured rock. It can cover the full temperature range used for volatilization, hydrolysis, and biological enhancement.
For boiling-point treatment, vapor extraction maintains pneumatic control and captures contaminants. Multiphase extraction may be incorporated where groundwater inflow or mobile non-aqueous phase liquid requires hydraulic control and recovery.
Steam Enhanced Extraction (SEE)
SEE injects steam into permeable saturated formations to deliver heat rapidly, mobilize non-aqueous phase liquid, and strip halogenated VOCs. It is best suited to sands, gravels, permeable fill, and connected fractured-rock systems that distribute steam effectively. Because steam is injected under pressure and condenses as water, a carefully designed extraction network is needed to recover vapor, groundwater, and product and maintain pneumatic and hydraulic control.
SEE is used for boiling-point treatment and is not normally selected for controlled hydrolysis or biological enhancement below 100°C. At heterogeneous sites, SEE can be combined with ERH or TCH so that steam treats permeable intervals while resistive or conductive heating addresses lower-permeability zones.
Will Thermal Work for Your Site?
Tell us about your site and we'll tell you whether thermal treatment applies and which approach fits. If it isn't the right remedy, we'll say so.
How Does Thermal Compare to Other Methods?
Soil vapor extraction, air sparging, groundwater extraction, natural attenuation, and biological or chemical remedies can play important roles. Their performance may be limited by non-aqueous phase liquid, low-permeability soil, fractured rock, nonuniform amendment delivery, unfavorable geochemistry, or long treatment periods.
Thermal remediation increases vapor pressure, diffusion, desorption, dissolution, and reaction rates within the source zone. It can transfer contaminants from liquid and sorbed phases into recoverable forms and accelerate hydrolysis or biological degradation where applicable. Thermal is often most valuable in high-mass source zones, followed by lower-intensity treatment of residual or downgradient contamination.
Choosing the Right Solution
TerraTherm tailors each remedy to the site and cleanup objectives. Our evaluation considers:
- Geology, permeability, and fracture characteristics
- Groundwater flow, recharge, and hydrogeologic conditions
- Treatment depth, geometry, access, and surrounding land use
- Contaminant identity, properties, concentration, mass, and phase distribution
- Amenability to hydrolysis or biological degradation
- Co-contaminants, soil organic carbon, moisture, and electrical resistivity
- Cleanup goals, endpoint metrics, schedule, energy, and extraction requirements
TCH and ERH are strong options for many sites. Selection depends on electrical resistivity, moisture, treatment depth, site heterogeneity, groundwater flow, and bedrock conditions. SEE can be advantageous in sufficiently permeable formations and can be combined with TCH or ERH where high- and low-permeability intervals occur together.
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Why TerraTherm? For a confidential site in the Midwest, TerraTherm used low-temperature ERH to accelerate hydrolysis of EDB, 1,2-bromochloroethane, and 1,2-dichloroethane in soil and groundwater. The approximately 14,387-cubic-yard treatment zone covered 31,077 square feet. A total of 137 electrodes heated the treatment zone to the minimum targeted hydrolysis temperature of 70°C; groundwater and soil results demonstrated that the remedy met the project shutdown requirements. The contingency vapor-extraction system was not operated because monitoring showed that the primary contaminants were being removed through hydrolysis at the targeted temperature, and vapor monitoring did not detect contaminants above action levels within or around the treatment zone. The project demonstrates how contaminant-specific chemistry can be used to achieve treatment objectives at temperatures below boiling. |
Ready to Address Halogenated VOCs, Refrigerants, or Fumigants at Your Site?
TerraTherm applies field-proven thermal technologies and data-driven design to complex source zones. We work with site owners, consultants, industrial operators, and regulators to define the treatment boundary, select the appropriate temperature and heating method, manage groundwater and vapor, and verify that cleanup objectives have been achieved.
TCH Technology Applicability
