Proven, Patented Process.
The Electro-Thermal Dynamic Stripping Process (ET-DSP™) was created and patented by Mc2 to remediate contaminated soil and groundwater. It involves the introduction of electrical current into the contaminated soil volume via electrodes strategically placed throughout a contaminated zone. The system is designed to use conventional and readily available three-phase power to transfer current to each individual electrode and heat the subsurface. The ET-DSP™ process maximizes the impact of all available heat transfer mechanisms to volatilize contaminants in-situ or to drive them to extraction wells via a guided steam front. Electrical heating increases the temperature of the soil and groundwater by conducting current through the interstitial water that fills the porosity voids in soil.
At any given instant, the electrical current passes from one electrode to another via this interstitial water. This temperature increase raises the vapor pressure of a soil volume, thus facilitating the in-situ removal of contamination by conventional techniques such as vapor extraction. Heating causes several changes in the subsurface conditions. For example, the soil resistivity decreases as the soil temperature increases. ET-DSP™ heating also tends to dry the soil as steam vapors are produced, resulting in soil dehydration. These changes are monitored and controlled continuously by a computer system that adjusts and optimizes electrical current flow through phasing or the measured introduction of moisture into the soil. These adjustments increase the conductivity and efficiency of the heating process. As a result, ET-DSP™ benefits from the 3 dominant mechanisms of heat transfer: conduction, convection, and electrical heating. The application of convective heating, accomplished by injecting water at controlled rates into the ends of the electrodes where the electrical field has the highest density, makes ET-DSP™ a far more effective heating technology than other forms of electro-thermal heating. Without the benefits of convective heat transfer, conventional remediation processes are limited by retardation of the contaminant in-situ, especially in fine sediments and clays. Therefore, primary technologies must be operated for long periods and may not achieve clean up standards in low-permeability soils or where the vapor pressure of the contaminant is low. To date, Mc2 has successfully implemented ET-DSP&trade on over 60 sites achieving clean up goals in each. In all cases, a significant reduction in contaminant was achieved within a period ranging from 3 to 8 months, versus the primary electro-thermal heating methods of potentially years.