Technology:
Composting
- Treatment structure was 33,000 ft2 modular building
- Included systems for leachate collection, aeration, inoculum growth and application, and wastewater treatment
- Ambient air was drawn down through soil pile
- Operating parameters included soil oxygen and moisture contents, pH, and nutrient levels
- Each batch of soil was treated to less than the cleanup goals within 14-30 days
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Cleanup Authority:
CERCLA
- ROD Date 3/29/90
- PRP Lead
SIC Code:
4953 W (Waste processing
facility, miscellaneous) | Point of Contact:
Mark Fite
USEPA Region 4
Atlanta Federal Center
100 Alabama St., S.W.
Atlanta, GA 30303
(404) 562-8927 |
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Contaminants:
Organic compounds volatiles, halogenated; volatiles, nonhalogenated (BTEX); semivolatiles, halogenated and semivolatiles, nonhalogenated (PAHs)
- Total VOC concentrations ranged from 0.022-38.27 mg/kg
- Total PAH concentrations ranged from 0.578-367 mg/kg
- PCP concentration ranged from 0.058-51 mg/kg |
Waste Source:
Waste Treatment Plant |
Type/Quantity of Media Treated:
Soil
- 19,705 tons of soil
- Lakeland loamy sand
- TPH 300-600 mg/kg
- Moisture content 8 |
Purpose/Significance of Application:
Full-scale application of composting to treat VOC- and PAH-contaminated soil |
Regulatory Requirements/Cleanup Goals:
- Total PAHs (sum of 17 specific constituents) less than 50 mg/kg
- Total xylenes less than 1.5 mg/kg; benzene less than 10 mg/kg; TCE less than 0.05 mg/kg; DCE less than 0.07 mg/kg; and PCP less than 50 mg/kg |
Results:
- Cleanup goal met for all constituents, with total PAHs in treated soil ranging from 3.3-49.9 mg/kg
- Of the 58,559 tons of soil excavated, only 19,705 tons exceeded cleanup goal and thus required treatment |
Cost Factors:
- Actual costs of $7,736,700 were reported by the PRP Steering Committee
- The cost for activities directly attributed to treatment was not provided separately from the total project cost, and therefore a unit cost for treatment was not calculated |
Description:
The Dubose Oil Product Co. Superfund site is a former waste treatment, recycling, and disposal facility that operated from 1979 to 1981. Operations performed at Dubose included thermal treatment of waste oil, petroleum refining wastes, oil-based solvents, and wood treatment wastes; steam heating of spent iron and pickle liquors; and rock salt filtration of waste diesel fuel. During a remedial investigation (RI), soil at the site was found to be contaminated with PAHs at concentrations ranging from 0.578 to 367 mg/kg total PAH, PCP ranging from 0.058 to 51 mg/kg, and VOCs ranging from 0.022 to 38.27 mg/kg.
A Record of Decision (ROD) was signed for this site in March 1990. Composting was selected in the ROD instead of in situ biological treatment because it was identified as easier to control and more reliable, and because it was believed that monitoring would be easier to perform. The composting system used at Dubose consisted of a treatment structure, a leachate collection system, an aeration system, an inoculum growth and application system, and an on-site wastewater treatment system. Contaminated soil was treated in batches, with each batch containing from 660 to 2,310 tons of soil. For most of the batches, soil depth ranged from 4.0 to 4.25 feet. Composting activities were performed from May to November 1993, and site restoration activities were completed by August 1996.
All 359 soil grids in the compost system met the soil cleanup goals established for Dubose. For total PAHs, before-treatment concentrations ranged from 50.8 to 576.2 mg/kg, while after-treatment concentrations ranged from 3.3 to 49.9 mg/kg (average - 19 mg/kg). For PCP, before-treatment concentrations ranged from 7.67 to 160 mg/kg, while after-treatment concentrations ranged from 16.5 to 36.3 mg/kg. The primary removal mechanism identified for VOCs in this application was volatilization, while for PAHs it was bioremediation. Several lessons were learned about operation of the composting system during this application. For example, the vendor indicated that applying an inoculum mixture with a fire hose provided for adequate diffusion of soil moisture. |
