Biodegradation, vapor extraction, and air sparging in low-permeability soils

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:467731

Aelion, C M; Ray, R P; Shaw, J N ^[1]; Widdowson, M A ^[2]; Reeves, H W ^[3]

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1. Univ. of South Carolina, Columbia, SC (United States)
2. Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Dept. of Civil Engineering
3. Northwestern Univ., Evanston, IL (United States). Dept. of Civil Engineering

Soil vapor extraction and air sparging (SVE/AS) were implemented to remediate a gasoline-contaminated aquifer in the slightly permeable saprolitic soil of the Appalachian Piedmont of South Carolina. Samples from exhaust gases and multilevel soil probes were collected. CO{sub 2} and O{sub 2} were used as indicators of biodegradation. A portable combined hydrocarbon/O{sub 2} meter and a CO{sub 2} meter were used on site to monitor levels of volatile hydrocarbons (HC), CO{sub 2}, and O{sub 2}. Field data were verified in the laboratory by gas chromatography (GC). During the 8-h daily SVE operation, exhaust-gas HC mass extraction rates were greatest at daily startup and were reduced to 1/3 of the initial rates after 1 h of operation and to 1/4 of the initial rates after 8 h of operation. During the rest period after SVE operation, concentrations of BTEX remained stable and O{sub 2} vapor concentrations in the vadose zone did not fall below 19%. Greater biodegradation appeared to occur as a result of SVE/AS. After SVE/AS, CO{sub 2} ranged from approximately 1 to 4%, with greatest CO{sub 2} and most depleted O{sub 2} measured near the water table and coinciding with greatest BTEX concentrations.

• OSTI ID: 467731
• Report Number(s): CONF-950483--; ISBN 1-57477-003-9
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
ALKYLATED AROMATICS
BENZENE
BIODEGRADATION
GAS INJECTION
GASOLINE
IN-SITU PROCESSING
OIL SPILLS
REMEDIAL ACTION
SOUTH CAROLINA
TOLUENE
XYLENES