10. Ex situ thermal desorption

Thermal desorption is the application of heat to extract volatile and semi-volatile pollutants from the soil by volatilization (figure 10 ). This technique is increasingly competitive with incineration.

• Principle

  Once the contaminated soil has been excavated, thermal desorption involves introducing it into a desorption unit (commonly known as a "furnace"), where it is heated to temperatures generally ranging from 150 to 540°C. This temperature increase serves two purposes:

  • promote the desorption of contaminants strongly adsorbed on soil particles,

  • increase the vapor pressure of low-volatility compounds so that they can be volatilized...