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LNAPL DISTRIBUTION AND HYDROCARBON VAPOR TRANSPORT IN THE CAPILLARY FRINGE
Citation:
Ostendorf, D. W., E. E. Moyer, R. J. Richards, E. S. Hinlein, Y. Xie, AND R. V. Rajan. LNAPL DISTRIBUTION AND HYDROCARBON VAPOR TRANSPORT IN THE CAPILLARY FRINGE. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/R-92/247 (NTIS 93-157550), 1992.
Impact/Purpose:
Information.
Description:
Vertical distributions of water and light nonaqueous phase liquid (LNAPL) from a well document aviation gasoline spill at the US Coast Guard Air Station in Traverse City, Michigan were measured. Two field sampling methods for the determination of LNAPL content were presented. Existing models for the free and residual LNAPL profiles described the data with calibrated error standard deviations ranging from 14 to 23% in magnitude. Field trapping protocol was also developed with sample ports fabricated in the intact core sleeves as part of the trapping method, which yielded total hydrocarbon concentration data consistent with independent data from a tubing cluster. he evaporation of 2,2,4 trimethylpentane and 2,2,5 trimethylhexane vapors from the LNAPL was measured in the laboratory under diffusive and advective conditions to simulate soil venting and sparging. The data and theory suggested that lower soil venting or sparging flow rates were in principle as effective as higher rates in stripping gasoline vapors from contaminated soils. he biodegradation of hydrocarbon vapors in soil microcosms obtained aseptically from the site was also documented. The microcosms featured an exterior water seal design that proved successful in the difficult task of vapor retention, and Michaelis-Menten type kinetics were fit to the data under substrate limiting conditions. The microcosm based kinetics were input to an existing model of coupled hydrocarbon and oxygen transport in an accurate prediction of independent field observations of the vapor concentrations.