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Sunoco Service Station / Massachusetts
During the removal of three gasoline USTs at this 3.4 acre site in 1995, volatile organic vapor (VOV) concentrations were detected above 100 ppm in soil headspace. The site was classified by the DEP as Tier IB in 1996. Between 1995 and 2000, approximately 2,000 cubic yards of impacted soil were removed from the site for recycling and landfill. In August, 2000 a biofeasibility study was conducted which confirmed that butane-utilizing bacteria are present in the groundwater at the site in the proposed treatment zone, and the populations of these bacteria would develop in sufficient numbers to complete full microbial oxidation of injected butane, as well as the cometabolism of benzene, MTBE and other gasoline constituents, the primary contaminants at the site.
The depth to groundwater at the site ranges from 3 to 10 feet below grade. The station property is underlain by brown fine to medium sand and fine to coarse gravel to a depth of approximately 10 feet below grade. The unit locally grades to a dark brown peat with silt to a depth of approximately 15 feet below grade. A layer of light gray silt and clay is encountered from approximately 20 to 25 feet below grade. Groundwater flow direction is radial, with a horizontal hydraulic gradient of 0.043 feet per foot (ft/ft) and groundwater flow velocity estimated to be 1.57 feet per year (ft/yr) across the property. The site is located within both a DEP Approved Zone II, and a Medium Yield Potentially Productive Aquifer. Public drinking water is supplied from several groundwater intake stations north and south of the site. Two nearby surface water bodies are classified as Class B waters, identified as habitat for fish, other aquatic life and wildlife, and for primary and secondary contact recreation. The property is also adjacent to a wetlands area. The site is located within an Area of Critical Environmental Concern with an area of Protected Open Space located within approximately 150 feet of the property.
A total of twelve injection wells were installed on-site, and in October, 2000, GBI installed two butane injection panels equipped with air compressors under a DEP approved RAM Plan. All groundwater sampling was conducted by Handex Corporation for Sunoco.
BUTANE BIOSTIMULATION TECHNOLOGIES
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Results
October 2000
(Pre-Butane Injection)
Xylenes = 2,000 ppb
C5-C8 Aliphatics = 1,900 ppb
C9-C10 Aromatics= 1,700 ppb
Benzene = 850 ppb
Toluene = 830 ppb
MTBE = 370 ppb
January 2001
(Post Butane Injection)
Xylenes = 61 ppb
C5-C8 Aliphatics = 98 ppb
C9-C10 Aromatics= 65 ppb
Benzene = 35 ppb
Toluene = 21 ppb
MTBE = 12 ppb
Contacts:
William Morse, Sunoco Inc
William Brochu, Handex Corporation
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Butane Biostimulation Technologies is a trademark of Global BioSciences, Inc.
Butane Injection System is a trademark of Global BioSciences, Inc.
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