Air sparging is a technology employed on contaminated sites, whereby pressurized air is injected directly into the groundwater. Through direct contact with the injected air, contaminants are stripped from the groundwater. The increased concentration of oxygen in the groundwater and soil also promotes biodegradation of contaminants. This technology can be used in the remediation of sites with both chlorinated-solvents and petroleum contamination.
A consideration in the use of air sparging is the movement of vapors through the soil towards the surface. Air sparge systems are often used in conjunction with soil-vapor extraction systems, creating a negative pressure in the soil to draw the contaminant-laden air out of the ground.
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.
Air sparge/soil vapor extraction systems typically employ a compressor to pressurize ambient air, a heat exchanger to reduce the temperature of the pressurized air stream, and a manifold to distribute the pressurized air stream to any number of injection wells installed on the site. 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 an air sparge/soil vapor extraction system include required air flow rates, air pressure and vacuum, and the number of injection extraction wells. Various types and sizes of compressors are available to satisfy almost any set of requirements.
Please follow the links to view the various types of equipment used in air sparge/soil vapor extraction systems.
