Enhanced mineral alteration by petroleum biodegradation in a freshwater aquifer

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

OSTI ID:484972

Hiebert, F K ^[1]; Bennett, P C; Folk, R L; Pope, S R ^[2]

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1. RMT/Jones and Neuse, Inc., Austin, TX (United States)
2. Univ. of Texas, Austin, TX (United States). Dept. of Geological Sciences

Aerobic and anaerobic microbial degradation of petroleum hydrocarbons in shallow aquifers disturbs the geochemical equilibrium between water and mineral phases and accelerates the dissolution and precipitation of minerals. These effect were investigated in an oil-contaminated aquifer near Bemidji, Minnesota, using in situ microcosms with a 14-month reaction period and field column experiments. Minerals recovered from microcosms were studied by scanning electron microscopy (SEM). Groundwater chemistry was characterized before and after the experiment. The in situ microcosms yielded feldspar and quartz grains colonized with a variety of bacteria. On a microscale feldspars, quartz, and, in some cases, calcite dissolved in the immediate vicinity of attached bacteria, even though the saturation indices for these minerals in the bulk groundwater indicated that little to no dissolution should occur. On a local scale the metabolic production of CO{sub 2} and HCO{sub 3} resulting from acetate methanogenesis and the oxidation of aromatic hydrocarbons coupled with iron reduction provided a supply of reactants to the groundwater. Calcite precipitated in a wide variety of spiky morphologies and clay minerals formed on feldspar minerals.

• Sponsoring Organization: National Science Foundation, Washington, DC (United States); Geological Survey, Reston, VA (United States)
• OSTI ID: 484972
• Report Number(s): CONF-950483--; ISBN 1-57477-009-8
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
AQUIFERS
BIODEGRADATION
ENVIRONMENTAL EFFECTS
HYDROCARBONS
IN-SITU PROCESSING
MINERALS
MINNESOTA
OIL SPILLS
OPTIMIZATION
REMEDIAL ACTION
WATER CHEMISTRY