Soil vapor extraction systems apply negative pressure (vacuum) to the unsaturated soil, facilitating the removal of contaminated vapors. This vapor stream is typically separated into liquid and vapor, which are then treated separately. The movement of air through the soil also promotes biodegradation of contaminants. Soil vapor extraction (SVE) systems can be used in the remediation of sites with both chlorinated solvents and petroleum contamination.
Negative pressure is created in the extraction wells by a vacuum blower installed in the treatment system. Contaminated vapors from extraction wells are combined into one stream, usually at the treatment system, using a manifold. A vapor/liquid separator then separates the majority of the entrained liquid. The liquid stream is held in the vapor/liquid separator and discharged or treated as required, while the vapor stream is extracted by the vacuum blower. The effluent vapor is either discharged or treated, using activated carbon or an oxidizer, and then discharged.
Considerations in the design of a soil vapor extraction system include: the number of extraction wells, required air flow rate, required vacuum, expected water flow rate, levels of contaminants, and discharge requirements. Various types and sizes of vacuum pumps are available, as are an assortment of vapor-treatment technologies.
Depending on the site conditions and application, soil vapor extraction systems can be combined with air sparge systems, or with pump and treat systems to enhance performance.
Please follow the links to view the various types of equipment used in soil vapor extraction systems.
