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Other in-situ Thermal Methods

Other methods of in-situ thermal treatment are resistive heating and conductive heating, which like steam work on the basis of introducing heat into the treatment zone.

Other methods of in-situ thermal treatment are resistive heating and conductive heating, which like steam work on the basis of introducing heat into the treatment zone. Resistive heating uses high currents applied between electrodes to heat soil in a similar manner to that of a light bulb element. The temperatures generated by this type of system can see soil being heated to temperatures in excess of 100oC.

Conductive heating is a much more simple system that uses heater elements, the analogy on this occasion would be the element in a kettle. Conductive heating is often used in low permeability soils that have greater conductive properties. It can also be used in tandem with steam injection to provide a greater overall targeting of the subsurface. The heater elements can reach temperatures in excess of 300oC.

Both of these systems can be more effective in lower permeability, clay rich soils due to the better conductive properties of this media. Consideration must be given to Health and Safety and design of the recovery systems used to capture and extract mobilised contaminants. These recovery systems are similar to those designed in the steam enhanced recovery section.