Thermal treatment is a process for cleaning contaminated soil in which the soil is heated to a high temperature. This destroys the pollutants in the soil through chemical and physical processes or converts them into non-toxic substances. Thermal treatment can be divided into several steps:

1. Pre-treatment
   In this step, the soil is sorted and coarse impurities, such as large stones or roots, are removed. This ensures that the soil is heated evenly.
2. Heating
   In this step, the soil is heated to a temperature of around 200 to 400 degrees Celsius using special heating technology. There are various methods for this, such as the flow-through method or the fluidised bed method. The flow-through method works with continuous soil transport and even heat distribution, while the fluidised bed method heats the soil through air movements in a fluidised bed.
3. Cooling
   Once the floor has been heated sufficiently, it is cooled to prevent damage to the floor. For example, water or air can be used as a coolant.
4. Analysis
   After thermal treatment, the soil is analysed for the residual concentration of pollutants. This involves checking whether the pollutants have been completely broken down by the thermal treatment or whether there is still residual contamination.

The advantage of thermal treatment is that it is also suitable for heavily contaminated soils and a high level of remediation can be achieved in a short time. However, the costs of thermal treatment are comparatively high and a lot of energy is required to heat the soil. In addition, some undesirable by-products can also be produced, such as nitrogen oxides or dioxins.

Overall, thermal treatment is a promising method for remediating contaminated soil, especially when other methods are not sufficient or a quick result is required. However, the feasibility and cost-effectiveness of the process should be checked before use.