EG&G's™ Aerobic Biofiltration System for the Destruction of Hydrocarbon Vapors from Fuel-Contaminated Soils

Site Name:

Patrick Air Force Base

Location:

Florida

Period of
Operation:

1/15/94 to 2/26/94

Cleanup
Type:

Field demonstration

Vendor:

EG&G
Rotron Division
Saugerties, NY

Sponsor:

U.S. Air Force
Center for Environmental Excellence
Technology Transfer Division
Brooks AFB, TX

Technology:
Biocube™ (supplement to SVE)
- Demonstration used an above-ground biofiltration unit, consisting of a proprietary mixture of inorganic and organic substrate containing active bacteria
- Unit removed hydrocarbons by adsorption and biodegradation
- Soil vapors from a horizontal vent well at 4 ft bgs passed through knockout drum and diluted with fresh air to maintain an influent concentration of 1,000 ppm, then passed through a humidifier prior to the Biocube™
- A recirculation loop was installed to allow multiple passes through the biofilter
- Air emissions from the biofilter were passed through vapor-phase carbon prior to discharge; three 55-gal drums were used

Cleanup Authority:
RCRA UST

Contaminants:
Volatile hydrocarbons and BTEX
- Initial soil gas contained TVH of 2,400 ppmv in study area

Waste Source:
Leaks from USTs

Type/Quantity of Media Treated:
Soil vapors
- Average depth to water table is 5 ft

Purpose/Significance of Application:
Treatment of extracted vapors from an SVE system

Regulatory Requirements/Cleanup Goals:
- Test objectives were to remove BTEX - >90% and TVH - >75%, based on an influent concentration of 1,000 ppmv

Results:
- In first 8 days of operation, at a flow rate of 30 scfm, no measurable differences were detected between Biocube™ influent and effluent, and the system was reconfigured
- Maximum removal efficiencies of 90.8% for BTEX and 29.5% for TVH were achieved at very low loading rates and flow rate of 3.2 scfm
- At a 49 scfm flow rate, removal efficiencies were BTEX of 40% and TVH of 18%
- Limitations experienced during the demonstration included a relatively slow system acclimation; vacuum leaks and dilution of process gas; and inaccurate flow measurements

Cost Factors:
- Full-scale cost estimates were not provided based on this demonstration
- Costs provided by other biofiltration vendors showed unit costs of $18.66/kg to $38.06/kg, for TVH influent concentrations of 1,000 to 2,000 ppmv and flow rates of 20 40 scfm

Description:
A field demonstration of the Biocube™ aerobic biofiltration system technology was conducted at Patrick Air Force Base in Florida to determine the effectiveness of the technology in reducing VOCs in extracted soil vapors prior to release to the atmosphere. The BiocubeTM demonstration was tested on the soil vapors extracted from a single extraction well at the Base Exchange service station.

The target removal efficiencies could be achieved only when the flow rate and loading were reduced to impractically low levels. As such, the Biocube™ could not be used as the primary vapor treatment technology when high BTEX and TVH removal efficiencies were required.