TerraTherm offers Electrical Resistance Heating (ERH). ERH has been widely applied and proven effective for free product recovery and enhanced vapor extraction at sites with volatile contaminants such as VOCs, CVOCs, and NAPLs, and is applied at low and moderate temperatures.
When electric current is passed through the soil, the resistance it encounters causes the soil and fluids to heat up. The current flows from one electrode to another, primarily through the soil water. Once the water boils off, electrical conductivity becomes negligible and heating ceases; thus, water is added at each electrode to keep them from drying out. Heat-up with Electrical Resitance Heating is limited to the boiling point of water. McMillan-McGee’s ET-DSP technology is an advanced version of Electrical Resistance Heating.
Electrodes are installed in wells throughout the contaminated soil and groundwater volume. The electrode array is connected to a Power Delivery System unit that uses standard, readily available three-phase power from the grid. The process begins by passing current between electrodes causing the soil temperature to rise. This increased temperature results in the volatilization of contaminant compounds into the vapor phase for removal with vapor extraction techniques.
Comprehensive computer controls are used to regulate and optimize the thermal response of the target formation.
ET-DSP features efficient energy delivery, convective heat transfer in permeable settings, uniform temperature distribution, and digital real-time monitoring. These features are not found in previous generations of Electrical Resistance Heating technologies. ET-DSP project cycles are also shorter because of its rapid installation process and quick achievement of target temperatures.
- Superior energy delivery and heat transfer achieved through custom-built electrodes that provide higher output and improved control;
- More effective energy delivery and subsurface heating provided by real-time computerized power controls for each electrode;
- Convective energy delivery is available in permeable settings, making it possible to generate and inject steam for additional heating and contaminant flushing; and,
- Safety and process transparency are enhanced for both the project team and client with real-time Digital-at-the-source temperature and monitoring.