Technology:
In Situ Bioremediation using ORC®
- The UST was removed and soil was excavated in two areas at the site prior to application of ORC®
- A total of 140 lbs of ORC® was injected in the excavated areas
- The one time application of ORC® was performed on August 31, 1998, with an injection depth of 20 - 25 feet (ft) below ground surface (bgs)
- Seven monitoring wells were located around the excavation areas
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Cleanup Authority:
RCRA UST
Site Contact:
Youman's Gas & Oil
P.O. Box 399
Hollywood, SC 29449
Telephone: (843) 889-2212 | State Contact:
Scott McInnis
South Carolina Dept. of Health
and Environmental Control
2600 Bull Street
Columbia, SC 29201
Telephone: (803) 898-4350
Fax: (803) 898-4330
E-mail: mcinniwa@columb26.dhec.state.sc.us |
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Contaminants:
MTBE, BTEX, Naphthalene
- MTBE concentrations as high as 2,230 ug/L
- BTEX concentrations as high as 28,600 ug/L for toluene
- Naphthalene concentrations as high as 134 ug/L |
Waste Source:
Leaks from an underground gasoline storage tank (UST) |
Type/Quantity of Media Treated:
Groundwater
- Average depth to groundwater is 9 feet below ground surface (bgs)
- Average hydraulic gradient is 0.006 ft/ft with a calculated seepage velocity of 0.473 feet per year |
Purpose/Significance of Application:
Use of in situ bioremediation using ORC® to treat MTBE in groundwater |
Regulatory Requirements/Cleanup Goals:
- Site-specific target levels (SSTLs) were established by SCDHEC for MTBE, BTEX constituents (benzene, toluene, ethylbenzene, and xylenes), and naphthalene
- SSTLs for well MW-0 were: MTBE - 239 ug/L; benzene - 4,150 ug/L; toluene - 21,400 ug/L; ethylbenzene - 1,700 ug/L; xylenes - 11,700 ug/L; and naphthalene - 557 ug/L
- SSTLS for well MW-5 were: MTBE - 115 ug/L; benzene - 4,020 ug/L; toluene -2,900 ug/L; ethylbenzene - 460 ug/L; xylenes - 2,380 ug/L; and naphthalene - 170 ug/L |
Results:
- According to SCDHEC, cleanup goals at the site were met in November 1998
- Results of the January confirmation sampling event showed that the SSTLs had been met for MTBE, BTEX, and naphthalene in wells MW-0 and MW-5, with concentrations of MTBE and naphthalene below detection limits in both wells
- Concentrations of BTEX constituents were reduced by 99% in well MW-5, and by as much as 95% (benzene) in well MW-0
- The SCDHEC reported that the corrective action was completed on July 24, 2000. |
Cost Factors:
- The total cost for the cleanup at this site was $21,000
- The South Carolina Petroleum Cleanup Fund awarded the contract for the cleanup at this site as a fixed-price, lump sum with no change orders; no additional information on cost breakdown was available. |
Description:
The Cordray's site is the location of a former gasoline service station. In 1987, leaks from a gasoline underground storage tank (UST) resulted in contamination of soil and groundwater at the site with MTBE, BTEX, and naphthalene. A 550-gallon UST was removed in 1987 and a Corrective Action Plan (CAP) was implemented in April 1998 under Subtitle I of the RCRA program. The CAP included excavation of soil and in situ bioremediation of groundwater using ORC®. Soils were excavated in two areas, with ORC® injected into the excavated areas.
On August 31, 1998, a one time application of 140 lbs. of ORC® was performed in the excavated areas, at an injection depth of 20 - 25 ft bgs. Cleanup goals at the site were met in November 1998, and confirmed during a January 1999 confirmation sampling event. Concentrations of MTBE and naphthalene were reduced to below detection limits in wells MW-0 and MW-5; concentrations of BTEX constituents were reduced by 99% in well MW-5, and by as much as 95% in well MW-0. According to SCDHEC, the corrective action was completed on July 24, 2000. In addition, the SCDHEC indicated that the cleanup was completed within the predicted time, and the use of a fixed price contract (total cost of $21,000) was less costly than a time and materials contract. |
