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Based on the experimental evidence and th_se simulations, it is probable that the glass displacement events in ISV melts are caused by sudden gas releases. ® Adjacent melts or other media that block vapor transport on three sides of the melt slightly increase (~0.5 psig) the gas pressure beneath the melt. The temperature aJ_dsaturation distributions in the soil are drarnatically affected by such structures. ® Melt growth down the electrodes is likely to be the normal mode of melt progression for fixed electrode tests, This can probably be avoided by dynamically feeding the electrodes downward as the melt advances. • Phase resistance between electrodes in a melt can be accurately predicted by TEMPEST and a simple equation presented in this paper, Melt diameter can be predicted given phase resistance and centerline depth, However, melt growth down fixed electrodes _ be distinguished from an oblate spheroid melt shape using melt centerline depth and phase resistance information.

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The Six‐Phase Soil Heating (SPSH) technology was demonstrated to be capable of heating and remediating low‐permeability soils containing volatile organic compounds (VOCs). Six‐Phase Soil Heating accelerated the removal of VOCs from clay soils, removing over 99 percent of the contaminants in only 25 days. Soil temperature profiles showed that SPSH was successful in heating the targeted clay zone that contained higher levels of soil contamination. The success of SPSH has resulted in its planned use and consideration by potential commercial partners for use at private industrial and other government sites.

Numerical simulation is used to test the effect of several parameters on the water balance and pressure field surrounding a growing hemispherical In Situ Vitrification (ISV) melt. In the current project, a hemispherical annulus of unsaturated soil contained between a growing melt and an impervious wall is modeled. Water vapor vents to atmospheric conditions. The soil is considered a porous media; consequently, fluid velocity can be modeled by Darcy’s equation. The capillary pressure and relative permeability are modeled using the equations derived by van Genuchten. The computer model employs a grid which adapts to the transient boundary of the growing melt. The parameters considered include: initial liquid saturation, soil permeability, and melt growth rate. The combined effect of capillary pressure and permeability is also studied. The variation of these parameters in a Hanford soil are studied for their effect on pressure history at the melt interface and total liquid mass history. Transport of heat and mass in the soil is illustrated graphically in terms of the saturation and pressure fields as well as mass flux of liquid and vapor water.