United States
                Environmental Protection
                 Solid Waste and
                 Emergency Response
October 1993
Ground water
Remediation  For
UST Sites
In Situ Bioventing
Combined With  Low
Flow Air Sparging
                 In situ bioventing combined with low flow air sparging
                 (biosparging) stimulates the aerobic biodegradation of
                organic contaminants in groundwater by delivering
                oxygen to the saturated and unsaturated zones. The oxygen
                is delivered at a slow rate to encourage biodegradation
                rather than volatilization.

                Biosparging degrades volatile organic compounds (VOCs)
                in place, reducing the need for subsequent vapor
                treatment and the costs of remediation. This technique
                is most effective in permeable aquifers.
                   Petroleum Types And Constituents

                   * Fresh or weathered gasoline, diesel, jet fuel,
                    kerosene, motor oil, fuel oil, lubricating oils,
                    and crude oils

                   * Volatile organic compounds (VOCs) such as
                    benzene, toluene, ethylbenzene, and xylene (BTEX);
                    and residual semivolatile organic compounds
                    (SVOCs) such as polynuclear aromatic

  In Situ Bioventing Combined With Low Flow Air Sparging
 Degrades volatile organic compounds (VOCs) in place
 Reduces air emissions and subsequent need for vapor
 Effectiveness is limited in low permeability or
  heterogeneous media
 Difficult to control air distribution in groundwater
 Limited performance data available
 Vertical or horizontal extraction and injection wells
 Vacuum pump, compressor, or blower
 Aboveground vapor treatment (optional)
  Vapor treatment options (might be needed for high
  concentrations of contaminants):
     Vapor phase biofllters
     Granulated activated carbon
     Internal combustion engine
     Catalytic oxidation unit
     Thermal incinerator
  Parameters to
  Vacuum/pressure monitoring at the pump, compressor,
  blower, and observation points
  Airflow rate
  Dissolved oxygen
  Water levels
  Constituent concentrations in groundwater
  Cleanup Levels
  and Timing2
 Generally achieves maximum contaminant levels (MCLs)
  for volatile constituents
 New application; to date, few sites have been fully
 Estimates for an ideal site4, $60,000 to $180,000
 Estimates for an average site3, $120,000 to $200,000
 Costs vary depending on vapor treatment costs and
  treatment time
'"Parameters to monitor" are for performance purposes only; compliance monitoring parameters vary by state.
3Costs include equipment, and operation and maintenance.
4An Ideal site" assumes no delays h corrective acton and a relatively roiiogenous, permeable subsurface.
5An "average site* assumes minimal delays in corrective action and a moderately heterogeneous and permeable subsurface.