What is Thermal Remediation?
Thermal remediation is a technique for removing or destroying subsurface contaminants through the application of heat.
It is an especially effective treatment option on sites involving hard-to-treat contaminants like NAPLs, where contamination has leached deep below surface, where there is high potential reuse value, or when excavation is not an option. When thermal remediation is utilized in situ (below ground), heat is applied to the treatment zone and, depending on the contaminant, it will enter a gaseous phase that can move more easily through the soil (or if the heat is high enough, the contaminants will be destroyed). To prevent the escape of the contaminant vapor and to remove the contaminant mass from the treatment zone, extraction wells are installed to collect and remove it. Thermal remediation can also be applied ex situ, or in an above-ground pile.
Thermal remediation has emerged as the most reliable in situ technology for the removal of a wide variety of organic contaminants from soil and groundwater. Thermal remediation can achieve the removal of chlorinated solvents, petroleum hydrocarbons, polyromantic hydrocarbons such as naphthalene and coal tars/creosote, pesticides, and PCBs to meet stringent soil and groundwater cleanup criteria. Thermal technologies have a proven track record for treating both dense and light nonaqueous phase liquids (NAPLs) in soil and bedrock, above and below the water table. Thermal remediation can also be applied ex situ using our in-pile thermal desorption (IPTD®) technology.
There are three methods of applying thermal remediation: thermal conduction heating (TCH), electrical resistance heating (ERH), and steam enhanced extraction (SEE). Each can be used individually or in conjunction with one another or other remediation technologies.
TerraTherm, a Cascade Company provides support for evaluation and selection of the correct thermal technology. We also design, build and operate in situ thermal remediation systems using TCH, SEE, ERH, and combinations of the technologies.
Our 70 full-time staff are experienced in managing projects from concept to completion, and can work with consulting firms and clients in whatever capacity we’re needed.
Having worked on hundreds of sites, our team understands that each one comes with its own complexities. We offer unbiased remedy selection and can develop tailor-made solutions for even the most challenging sites by combining multiple technologies.
TerraTherm offers all major thermal treatment options and has decades of experience implementing them.
TCH is the most flexible thermal technology and can be applied in situ or ex situ, to soil or groundwater, and is appropriate for addressing VOCs, SVOCs, PAHs, PCB, dioxins, LNAPL, DNAPL, PFAS and others. TCH is the only in situ thermal technology that can reach temperatures up to or above 350°C.
ERH can be highly effective at sites with relatively uniform soil resistivity. At such sites, ERH electrodes can be installed at wider spacing and heat up times can be shorter. Optimal sites include saturated silts, sandy silts, clayey sands, and some clays. Because ERH relies on soil moisture for conducting electrical current to heat the soil, maximum treatment temperature is limited to approximately 100°C. At this treatment temperature ERH can be used to treat VOCs, CVOCs, LNAPL and DNAPL.
SEE is a highly effective and efficient technology in permeable geologies and can be used for the recovery of free product and the remediation of VOCs. SEE achieves on-site separation and treatment through steam injection into wells and extraction of hot fluids. Steam propagation is a stable and predictable process, governed by heat transfer to the formation and has been studied intensively and utilized for oil recovery and remediation of a wide range of contaminants. SEE is often used in combination with TCH or ERH.
Combined remedies are appropriate for complex sites with limited success with previous remedies.
TerraTherm has the materials, facilities, equipment, personnel and experience to design, build, operate, and complete your thermal remediation project. Our field construction and operations approach has been honed by extensive project experience in numerous worldwide locations and a wide variety of settings.