The Soil Washing is a treatment for the remediation of contaminated land, in order to recover valuable part of the medium through a process of physical separation of the pollutant.
The Soil Washing technique can be done either on-site or off-site.
The Soil Washing is based on the principle that contaminants are conveyed through the finest particles present in the soil fractions and consists in performing a real washing (washing) with water, aqueous solutions of surfactants, biosurfactants, or with organic solvents.
The methods on which is based the removal of the contaminants are two:
- complete dissolution of the contaminants in the aqueous extraction solution;
- concentration and eventual dispersion of the contaminants in the extraction solution, in the form of suspended particles.
The Soil Washing technique can be used in combination with the technique to extraction with solvent, especially in the land in which occurs a mixed contamination.