United States           Solid Waste and          EPA510-F-93-017
Environmental Protection     Emergency Response       October 1993
Agency              5403W

Groundwater
Remediation For
UST Sites

In Situ Air Sparging With
Soil  Vapor Extraction
  In situ air sparging with soil vapor extraction (SVE) is
  a technique for removing dissolved volatile contaminants
from groundwater. The technique injects air into the
saturated zone. The air forms bubbles that rise into the
unsaturated zone, carrying trapped and dissolved
contaminants. Extraction wells in the unsaturated zone
capture sparged air. If necessary,  the air can then be
treated using a variety of vapor treatment options.

This technique is most effective in homogenous, permeable
aquifers. Performance data for this technique are limited.

In situ air sparging with soil vapor extraction is a rapid
remediation technique that can reduce contamination
levels in six months. It is also able to quickly remove
volatile organic compounds (VOCs) from below the
groundwater table.
   Petroleum Types And Constituents

   • Gasoline and diesel

   * Volatile organic compounds (VOCs) such as
     benzene, toluene, ethylbenzene, andxylene(BTEX)
 U S WOTKENTAl PROTECTION

 I ^ii'KtSS AVENUE

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In Situ Air Sparging With Son Vapor Extraction
Advantages
Limitations
System
Components
Wastestream
Treatment
Parameters to
Monitor1
Cleanup Levels
and Timing2
Costs3
• Rapidly reduces volatile organic compounds (VOCs) from
below groundwater table
• Can enhance and accelerate effectiveness of soil vapor
extraction (SVE) and downgradient pumping
• Removes primarily volatile constituents
• Effectiveness is limited in low permeability or
heterogeneous media
• Difficult to control air distribution in groundwater
• Can promote vapor and plume migration
• Limited performance data are available; contaminant
levels may rebound over time
• Vertical or horizontal extraction and injection wells
• Trenches
• Vacuum pump, compressor, or blower
• Aboveground vapor treatment equipment (optional)
• Vapor treatment options (if needed):
• Vapor phase biofUter
• Granulated activated carbon
• Internal combustion engine
• Catalytic oxidation unit
• Thermal incinerator
• Vacuum/pressure monitoring at the wellhead, pump,
compressor, blower, and observation points
• Airflow rate
• Vapor concentrations
• Dissolved oxygen
• Water levels
• Constituent concentrations in groundwater and soil
• Generally achieves maximum contaminant levels (MCLs)
for volatile constituents
• For an ideal site3, ~90% reduction in 6 months to 1 year
• For an average site4, ~90% reduction in 6 months to 2
years
• For an ideal site3, $60,000 to $180,000
• For an average site4, $120,000 to $200,000
'"Parameters to monitor" are for performance purposes only; compliance monitoring parameters van; by state.
3An 'ideal site* assumes no delays in corrective action and a relatively homogenous, permeable subsurface.
4 An "average site" assumes minimal delays in corrective action and a moderately heterogeneous and permeable subsurface.
5Costs include equipment, and operation and maintenance.

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