Remediation techniques

Remediation technologies can be categorized into in-situ or ex-situ methods.

Ex-situ remediation techniques

Ex-situ methods involve excavation and removal of contaminated soil, with subsequent on-site treatment or disposal to landfill.For these types of treatment, the polluted material goes under a pre-selection before the actual decontamination process.
Besides landfill disposal, the most common ex-situ remediation techniques are:
- Physical/Chemical Treatments
recommended for medium and coarse-grained soils, with metal and hydrocarbons contamination; for soils containing volatile organic compounds (VOCs) ; for soils and sludge contaminated by heavy metals, oils, hydrocarbons, vitrification and so on
- Thermal treatments, recommended for soils containing pesticides, hydrocarbons, chlorinated solvents
- Biological Treatments: suitable for soils where it is necessary to add oxygen and specific reducing components to the resident microbes.

In-situ remediation techniques

In-situ methods seek to treat contamination without removing the soils, with clear advantages in terms of environmental impact and material hauling. The in-situ techniques have, when possible, a relatively lower cost in comparison to the ex-situ methods.
The most common ex-situ remediation techniques are:
- Physical/Chemical Treatments; they rely on a process that removes contamination to later treat in on the surface
- Bioremediation, recommended for treating volatile organic compounds, with soil vapor extraction, to later process them on the surface