- Low temperature thermal desorption system owned by Williams Environmental Inc - direct-heated countercurrent rotary dryer fired by a 49 million BTU/hour burner, feed metering unit, baghouse, thermal oxidizer, and control unit that housed the controls, data logger, and analyzers.
- Average system throughput - 20 to 22 tons/hr
- Residence time - 15 to 20 minutes
- Average soil exit temperature - 800-1000 F
- ROD signed September 1993
Four Seasons Environmental, Inc.
P.O. Box 16590
Greensboro, NC 27416-0590
Telephone: (336) 273-2718
Fax: (336) 274-5798
Remedial Project Manager
EPA Region 5 (SR-6J)
77 West Jackson Blvd.
Chicago, IL 60604-3507
Telephone: (312) 886-4737
PAHs , Pyridine, Benzene
- Soil concentrations as high as 3,794 mg/kg for PAHs, 5,673 mg/kg for pyridine, and 191 mg/kg for benzene
Discharges from wood preserving and coal tar refinery operations
Type/Quantity of Media Treated:
- 3,700 tons of soil treated
- Moisture content - 15 to 30%
Purpose/Significance of Application:
Thermal desorption of soil containing PAHs, benzene, toluene, and pyridine from coal tar refining and wood preserving.
Regulatory Requirements/Cleanup Goals:
- Cleanup goals for soil specified in the ROD:
- Carcinogenic PAHs (benzo(a)pyrene equivalents) - 20 mg/kg
- Pyridine derivatives (510 mg/kg), pyridine (0.7 mg/kg), benzene (0.1 mg/kg), toluene (20 mg/kg)
- Stack gas emissions limits were specified for VOCs of 15 pounds per day
- 28 of 33 batches met the cleanup goals after initial treatment in the desorber. Five batches (about 925 tons of soil) that did not meet the cleanup goal for pyridine were retreated to meet these standards
- Air emissions were monitored during the one run performance test and met applicable emission limits
- The total cost for the thermal treatment application at this site was $1,087,732, including $270,000 in capital cost and $659,130 in O&M costs
- The unit cost for this application was $251/ton based on treating 3,700 tons of soil
The 120-acre Reilly Industries Superfund site (Reilly), previously known as Reilly Tar & Chemical (Indianapolis Plant), is a former coal tar refinery and creosote wood treatment plant located in Indianapolis, Indiana. The site includes the following five waste disposal areas: the Lime Pond area; the Abandoned Railway Trench; the Former Sludge Treatment Pit; the Former Drainage Ditch; and the South Landfill and Fire Pond. The Reilly site was added to the National Priorities List (NPL) in 1984. Contaminants of concern in the soil included PAHs, benzene, toluene, and pyridine, including its derivatives. In September 1993, a record of decision (ROD) was signed for operable unit (OU) 2 to address the contaminated soil and sludge in the disposal areas. The ROD required treatment of 11,000 tons of soil on site using thermal desorption. An explanation of significant differences (ESD) was signed in October 1997 to modify the remedy for OU 2, reducing the quantity of soil to be treated to 3,700 tons
The thermal treatment system used for this application was a low temperature thermal desorption system owned by Williams Environmental Services, Inc. Between November 1996 and January 1997, a total of 3,700 tons of contaminated soil were treated. The presence of elevated BTU and moisture content of the soil limited the amount of material that could be processed through the desorber. Engineering modifications, including blending soil, modifying the desorber to promote heat transfer, and reducing the soil screening cutoff size, did not increase the throughput rate. The vendor was able to treat only about one-third of the contaminated soil originally intended to be treated on site with thermal desorption because of this change in site conditions. The remaining contaminated soil was shipped off site for treatment using a boiler or industrial furnace. The total costs for the thermal treatment application $1,087,732, ($251/ton of soil treated).