Remediation professionals often select TCH for the treatment of VOCs, SVOCs, PCBs and PFAS. TCH involves heating wells to many hundreds of degrees Celsius. The heat propagates radially away from the heater wells at a rate usually less than an inch a day. Within the heating front, there is enormous (often more than 99%) contaminant mass removal, while beyond the front, there is minimal remediation. The tighter the heater well spacing, the faster a site will clean up. Typically, TRS spaces heater wells between 6 to 12 feet apart.
As the maximum temperature of water is its boiling temperature, TCH will desiccate the matrix where temperatures exceed the boiling point of water. Thus, soil moisture content has a profound impact of TCH energy requirements. While the boiling point of the contaminant and the percent mass removal will affect the remediation energy requirements, the more important design considerations are recharge, heater well density and time to meet the remediation goals.
TRS typically recommends ERH for VOC remediation and TCH for SVOC, PCBs and PFAS remediation. TRS can apply both technologies at a site to provide a low-cost solution using a unique, patent-pending invention, called the HybridHeater™ technology, which provides ERH and TCH in a single borehole, allowing TRS to target energy delivery efficiently, affording a cost-effective remediation solution.
When applying a single ISTR technology, it is sometimes difficult to achieve an optimal temperature in a permeable unit with fast-moving groundwater. Using the TCH portion of the HybridHeater™ technology, TRS can direct more energy to that zone.
Suppose you have VOCs in overburden and fractured crystalline bedrock, such as granite. As the granite has extremely low primary porosity, virtually all the contamination will be in the fractures. Although ERH can target the contamination in the overburden and fractures, the granite will remain cool. A simple solution is to heat the overburden with ERH and the rock with the TCH element. Providing both technologies in a single borehole can reduce costs dramatically.
TRS has developed a patent-pending, flexible heater element, called the FlexHeater™ technology. It is better, faster and less expensive than currently available TCH systems. The inventive design of the FlexHeater™ technology allows TRS to deliver varying amounts of heat vertically in discrete intervals in the heater well. Imagine putting a Slinky into a 2" pipe. The Slinky is a single wire, which, in our case, we can heat to about 900° Celsius. Although the wire is a single temperature, the Slinky-like design allows us to vary coil density throughout the entire length of the pipe. The greater the coil density, the greater the energy input to the formation.
Suppose you had a layer of PCBs at four feet below ground surface (bgs) and coal tar at the top of bedrock at 30 feet bgs. TRS could install the FlexHeater™ element so that we deliver more energy at the four and 30-foot horizons than at other depths. Once we clean those strata, TRS can easily pull out the element, quickly reconfigure it and put it back into the well.
Because of our ability to adjust the temperature profile of the FlexHeater™ system during scheduled breaks in operations, TRS will complete projects faster. TCH heater wells require essentially zero operation and maintenance - only periodic amp checks to verify that they are functioning.
Another advantage of the FlexHeater™ technology is how extremely easy it is to handle and ship. Our employee-owners can adjust the vertical temperature profile upon installation. As our heater element will fit inside a two-inch direct-push casing, installation costs are the lowest in the industry. Combined with completing projects faster, as described above, the FlexHeater™ technology can provide a low cost TCH solution.
TRS Thermal Conduction Heating (TCH)
TRS HybridHeater™ technology
TRS FlexHeater™ technology