United States           Solid Waste and          EPA 510-F-93-020
Environmental Protection     Emergency Response       October 1993
Agency              5403W

Groundwater
Remediation  For
UST Sites

Vacuum Enhanced
Pump And Treat
   Vacuum enhanced pump and treat is a technique that
   uses a surface-mounted vacuum pump to remove
contaminated soil vapors and groundwater simultaneously.
This method increases the rate of pumping, reducing
remediation time. The pumped water and soil vapors
can then be treated with a number of techniques.

Vacuum enhanced pump and treat is most effective when
used in aquifers with medium to low permeability (silts
and clays).

This method offers pumping rates that are 3 to 10 times
greater than conventional pump and treat rates.
Increased pumping rates result in decreased remediation
time.
   Petroleum Types And Constituents

   • Dissolved gasoline and diesel, jet fuel, and
    kerosene

   • Dissolved constituents such as benzene, toluene,
    ethylbenzene, and xylene (BTEX)

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Vacuum Enhanced Pump And Treat
Advantages
limitations
System
Components
Wastestream
Treatment
Parameters to
Monitor1
Cleanup Levels
and Timing2
Costs5
• Controls contaminant plume migration and reduces plume
concentrations
• Increases recovery rate of pumping by 3 to 10 times, reducing
remediation time
• Effective in aquifers with low permeability
• Can remove residuals from dewatered aquifer soils
• Can require treatment of vapors from vacuum pump
• Generates larger volume of water for treatment in a shorter
time than conventional pump and treat
• Requires control of water table fluctuation to minimize
smearing contaminants
• High iron content/hardness can affect water treatment
• Vertical or horizontal extraction wells
• Trenches
• Vacuum blower or pump
• Water pumps
• Aboveground air/water treatment systems
• Vapor treatment options:
• Vapor phase biofilter
• Granulated activated carbon
• Internal combustion engine
• Catalytic oxidation unit
• Thermal incinerator
• Water treatment options:
• Air stripping
• Granulated activated carbon
• Bioreactors
• Vacuum/pressure monitoring at well head, pump, blower
• Airflow rate
• Water discharge rate
• Water levels
• Constituent concentrations in groundwater
• Influent and effluent concentrations from water treatment
system
• Might not achieve maximum contaminant levels (MCLs)
• For an ideal site3, 6 months to 1 year
• For an average site4, 6 months to 2 years
• For an ideal site3, $80,000 to $120,000
• For an average site4, $100,000 to $180,000
• Higher initial costs than some alternatives, but shorter
remediation time might lower total cost
'"Parameters to monitor" are for performance purposes only; compliance monitoring parameters vary by state.
 An Ideal site* assumes no delays in corrective action and a relatively homogenous, permeable subsurface.
4An "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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