By injecting steam, soil and groundwater are heated. The heating causes an increase of the evaporation and solubility, and hence the mobility of the contamination. A mixture of phases (steam, air, water and pure product) is extracted through filters and is treated aboveground. Extracted soil vapor and groundwater are treated with techniques such as condensation, stripping, adsorption on active carbon and thermal oxidation.
Steam injection is applicable for volatile compounds, such as CVOC, BTEX and mineral oil. Steam injection is applicable for both the saturated and unsaturated zone in a moderate to well drained soil. In heterogeneous soils, layers with a high organic matter content extend the remediation period because of slow desorption. Steam injection is generally applied to the source of the contamination.
The duration of this technique is several weeks to months. The disturbance of the site is relatively high. Large surface facilities are needed (purification filters, steam generator) and there is a risk of overheating cables and pipes.
Related cases and HIP-pilots
Related cases: Amsterdam: mineral oil, BTEX **