Soil vapor extraction

Soil vapor extraction is an in-situ cleanup method that applies vacuum to wells in unsaturated soil, drawing volatile contaminants out as vapor for treatment or disposal.

Vacuum extraction well: A screened subsurface well connected to a vacuum system to draw soil gas toward the surface. It creates the pressure gradient that pulls contaminated vapor from the soil.
Volatile organic compounds: Organic chemicals that readily evaporate under ordinary environmental conditions. Their tendency to enter the gas phase makes them common soil vapor extraction targets.
Soil contamination: The presence of chemicals or other harmful substances in soil at concentrations that can pose risks. Extraction is one response to contamination located in the unsaturated soil.
Air sparging: An in-situ technique that injects air below the water table to strip volatile contaminants into groundwater-zone gas. It targets saturated soil and groundwater, while soil vapor extraction draws gas from above the water table.
Soil gas: The mixture of gases and vapors occupying pore spaces in unsaturated soil. Extracted soil gas carries volatile contaminants from the treatment zone.
Petroleum hydrocarbon remediation: The cleanup of petroleum-derived contaminants in soil and groundwater. Gasoline-range compounds in unsaturated soil can often be removed through vapor extraction.
Groundwater table: The upper surface of groundwater, below which saturated soil or rock occurs. Its depth defines the lower boundary of the zone treated by conventional soil vapor extraction.
Pump and treat: A groundwater remediation method that pumps contaminated water to the surface for treatment. It removes contaminants dissolved in groundwater rather than primarily extracting vapor from unsaturated soil.
Volatilization: The transfer of a substance from a liquid or solid phase into the gas phase. Contaminants must enter the vapor phase to be removed by this method.
Landfill gas extraction: The collection of gases generated by decomposing waste in a landfill. It also uses wells and vacuum, but targets generated landfill gas rather than soil contaminants.

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Environmental remediationRelated: It physically removes volatile compounds from contaminated soil without excavating it.