Heat it All the Way - Mechanisms and Results Achieved using In-Situ Thermal Remediation

In situ thermal remediation technologies have been proven to reach very low soil and groundwater concentrations by eliminating the dense non-aqueous phase liquid (DNAPL) source and reducing dissolved and adsorbed chlorinated volatile organic compound (CVOC) concentrations to near non-detect levels. For chlorinated solvents, vaporization is the dominant mechanism, as vapor pressure and Henry's law constants increase most markedly with temperature. For effective treatment, pneumatic and hydraulic control must be achieved during the heating period, and a clear path for the generated vapors to an extraction system must be provided. If remedial goals are stringent, target temperatures shall be the in-situ boiling point of the soil and groundwater system, such that a phase change to the vapor state is forced by the heating. During operation, detailed temperature monitoring and process sampling is conducted and compared to the performance calculated based on mass and energy balances. Interim and final sediment sampling is used to verify remedial progress and performance prior to site demobilization.