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NATURAL ATTENUATION OF FUEL HYDROCARBONS AT MULTIPLE AIR FORCE BASE DEMONSTRATION SITES
Citation:
Kampbell*, D H. NATURAL ATTENUATION OF FUEL HYDROCARBONS AT MULTIPLE AIR FORCE BASE DEMONSTRATION SITES. Presented at First International Congress on Petroleum Contaminated Soils, Sediments, & Water, London, UK, 08/15/2001.
Description:
A major initiative to evaluate monitored natural attenuation(MNA) of ground water contaminated with fuel hydrocarbons began in June 1993 and continued through October 2000. During this time site characterization studies, both initial and follow-up, were conducted at 28 Air Force bases within all ten USEPA regions. Main emphasis at spill sites at gasoline stations, jet fuel operations, fire-training and landfill areas was to evaluate natural degradation mechanisms to reduce dissolved fuel components of benzene, toluene, ethylbenzene, and xylenes(BTEX). A data base on historical loss of contaminants, presence of geochemical degradation processes, and validity of biodegradation models used was assimilated.
Historical ground water data obtained showed that 87 percent of the plumes were either stable or receding. Sulfate reduction was the most prominent attenuation mechanism followed by methanogenesis. Two-thirds of all sites had assimilative capacities that exceeded the dissolved BTEX concentration. The geometric mean of field biodegradation rates was 0.0019/day or about a half-life of one year. Bioplume was used at most sites to predict natural attenuation trends and support development of long term monitoring plans. The average time based on model assumptions required for natural attenuation to achieve Federal ground water quality standards for BTEX was 30 years. The time could be reduced to 15 years if more aggressive remediation was used such as excavation or bioslurping, but total cost estimates would increase from $192K to $816K. Annual sampling was recommended most frequently. The number of long term monitoring wells needed ranged from five to 22 with an average of 11. A case study of a jet fuel spill site will be discussed.
This is an abstract of a proposed presentation and does not necessarily reflect EPA policy.