SVOC & PAH Remediation
What Are SVOCs and PAHs and Why Are They a Problem?
Semi-volatile organic compounds (SVOCs) are a diverse class of chemicals characterized by lower volatility and higher boiling points than VOCs. Polycyclic aromatic hydrocarbons (PAHs), a significant subgroup of SVOCs, are composed of multiple fused aromatic rings and are commonly associated with coal tar, creosote, and petroleum residues. Both SVOCs and PAHs present substantial remediation challenges due to their persistence, toxicity, and strong affinity for soil organic matter.
Even at low concentrations, compounds such as benzo[a]pyrene and naphthalene pose significant risks to human health and the environment. Regulatory cleanup standards for these compounds are stringent, often requiring treatment down to parts-per-million or even parts-per-billion levels.
Common Sites with SVOC and PAH Contamination
- Former manufactured gas plant (MGP) sites
- Wood treatment and preservation facilities using creosote
- Petroleum refineries and bulk storage areas
- Railroad maintenance yards and transportation corridors
- Industrial fill, demolition debris, and landfill sites
Why Traditional Methods Often Fall Short
Non-thermal remediation approaches such as bioremediation, soil washing, excavation, and chemical oxidation frequently struggle with SVOCs and PAHs due to low bioavailability, strong sorption to soils, and chemical stability. These methods often result in partial mass removal, extended remediation timelines, and persistent long-term liabilities.
Thermal Remediation: Proven Performance for SVOCs and PAHs
TerraTherm’s thermal technologies apply controlled high temperatures to mobilize and extract SVOCs and PAHs from soil matrices. At elevated temperatures, some compounds may also undergo partial thermal degradation in situ. The majority of contaminant mass is volatilized, captured, and destroyed through vapor-phase treatment systems, resulting in significant overall mass reduction.
Our Solutions
Thermal Conduction Heating (TCH)
TCH is the only thermal technology that can heat soil and sediment to temperatures in the range required to effectively treat SVOCs and PAHs (300 to 400°C). Heating soil and sediment to these temperatures facilitates the volatilization and in situ destruction of SVOCs and PAHs. TCH relies on thermal conduction of energy from a heater into the surrounding soil or rock. TCH provides highly uniform and predictable heating because the thermal conductivity of most sites only varies by a factor of 2 to 3. Vapor extraction wells are required to maintain pneumatic control and recover volatilized COCs during treatment
In-Pile Thermal Desorption (IPTD®)
IPTD uses TCH to provide ex-situ thermal remediation of soil and sediment, treating any organic contaminant, including SVOCs and PAHs, and streamlining material handling while eliminating the need for off-site disposal of contaminated soils and sediment.
IPTD is highly flexible and easily customizable to optimize treatment of any soil volume, large or small. It involves placing contaminated soil and/or sediment within an engineered above-ground, fully covered and insulated treatment pile structure, and then heating the soil to the required temperature to destroy and/or remove the contaminants over periods of several weeks to several months. The design temperature and treatment period depend on the contaminants and remedial goals. For treatment of soil contaminated with SVOCs and PAHs, treatment temperatures between 300 and 400°C are typically required.
IPTD is a good fit for shallow soil contamination, excavated soil, or IDW when off-site disposal is not an option. On-site IPTD can be a cost-effective option for the total treatment of contaminants like PFAS, PCBs, dioxins, TPH, SVOCs, and PAHs, which eliminates the long-term liability of disposal of the soil in a landfill. Importantly stringent soil standards can be achieved even for recalcitrant contaminants like chlorinated pesticides.
IPTD has been used to treat soil volumes as low as 50 cy and up to 70,000 cy. The size of the pile depends on the volume of material to be treated, space available, electrical power available, and desired schedule.
How Does Thermal Compare to Other Methods?
Choosing the Right Solution
Each site requires a customized approach. TerraTherm engineers evaluate key factors, including:
- Soil type and permeability
- Contaminant depth and extent
- The mix of heavy versus lighter SVOCs and PAHs
- Presence of co-contaminants such as BTEX, PCP, or dioxins
- Regulatory timelines and performance goals
TCH is often preferred for treating persistent, high-molecular-weight PAHs in tight soils. ERH or SEE may be more appropriate for lighter compounds in moist or permeable subsurface. IPTD is a strong option for shallow, excavatable source zones requiring complete and controlled high treatment.
Regulatory Trends and Cleanup Goals
Remediation of SVOCs and PAHs typically follows USEPA SW846 Method 8270E for sample analysis. Cleanup standards continue to tighten due to increased awareness of health and ecological risks. State and federal agencies increasingly recognize thermal remediation as a preferred approach for achieving aggressive performance standards quickly and reliably.
Ready to Address SVOCs and PAHs at Your Site?
TerraTherm brings deep experience and field-proven thermal solutions to sites impacted by SVOCs and PAHs. Our systems are designed to achieve permanent results, reduce long-term liability, and support regulatory closure and site reuse.
Talk to a Thermal Remediation Expert
Explore Our SVOC & PAH Remediation Technologies:
TCH Technology Applicability
