In-Situ Thermal Desorption

The thermal desorption technology is applicable for removing volatile or semi-volatile organic contaminants. Veolia introduces thermal conductivity heating (TCH) whose temperature is higher than electrical resistance heating (ERH) and steam enhanced extraction (SEE). The target temperature is above 500 ℃, which is able to efficiently heat up intermediate to low permeability soil, also is insensible to geological inhomogeneity.

Technical principle:
  • As soil is heated, volatile contaminants in the soil are vaporized or destroyed by a number of mechanisms, including:
    (1) evaporation into the subsurface air stream introduced by application of vacuum, (2) steam distillation into the water vapor stream, (3) boiling, (4) oxidation, and (5) pyrolysis
  • Depending on the depth of treatment, an array of either thermal blankets or vacuum/heater wells are used;
  • Produced vapors are treated with an air pollution control system to remove residual contaminants that have not been destroyed in situ.

Technical advantages:
  • Achieves high clean-up standards
  • Fast remediation – 99% removal in 3-6 months;
  • Wide range of target compounds, soil and underground water can be treated at the same time;
  • Applicable beneath buildings.

Applicable contaminated sites:
  • Applicable for sites which cannot be excavated;
  • Organic contaminated sites such as petrochemical industry, underground tank farm, lumber mills and pesticides warehouse, and etc.