High Vacuum

Definition

• Applies a high vacuum (>15" Hg) to a vertical or horizontal well in low permeability soil matrices.
• Induces air to flow through the soil matrix void spaces toward the well(s), extracting contaminants from the subsurface as a vapor.
• Partitions volatile and semi-volatile contaminants into the vapor phase and extracts them from the soil matrix.

Application

• Volatile and semi-volatile compounds, including: Chlorinated solvents (PCE, TCE, DCE, etc.), petroleum hydrocarbons (gasoline, jet fuel, etc.), Stoddard Solvent, mercury and many others.
• Soil matrices of silts and clays and bedrock in widely varying geologic settings and at depths up to 300 feet.
• Typical soil permeability range of 0.001 to 10 millidarcies (equivalent to 10E-8 to 10E-4 cm/s hydraulic conductivity).

Unique Characteristics

• Allows the application of the vacuum extraction process in lower permeability soil matrices that have been typically considered impractical for vacuum extraction
• Stresses low permeability soils, creating advective flow pathways through high vacuum and vacuum desiccation.
• In situ technology minimizes site or property disturbances. Can be performed under existing buildings and structures.
• Increases the number of subsurface paths for advective versus diffusive flow, resulting in increased contaminant mass removal and accelerated remediation.

Case Studies

• Service Station, Monroe, LA
• Metals Fabracation Facility, CT

Technical Papers

• Integrated Pneumatic Soil Fracturing System/Vacuum Extraction For Remediation of Low Permeability Soils
• In Situ Bioremediation in Low Permeability Silt and Clay Soils