| Abstract
| - By in situ heating, contaminants can be mobilized byvaporization, modified into a harmless chemical state, orentrapped by soil vitrification. However, effective heatingmay be difficult or impossible by depending solely uponconduction of heat externally applied to a contaminatedtarget layer. Heating a layer internally by passing an electriccurrent through it has been employed in several differentin situ remediation field experiments. We present a three-dimensional computer model of groundwater flow andtransport in an electrically heated, partially saturated, porousregime. Simulations are used to show that the uniformityof heating can be enhanced by increasing the number ofelectrical phases employed in supplying current to theelectrodes. However, a more serious concern for the field-scale application of this internal heating method is thenonuniform heating of the target layer because of largeheating-rate differences between the near-electrode regionand the center of the array. Finally, for a dissolvedsolvent like TCE, we show that ohmic heating is exceptionallyeffective at clearing the layer by vapor-phase partitioning.Once expelled from the low-permeability layer, thesolvent that is not already thermally destroyed by a pyrolyticreaction is available for extraction.
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