- Thermal treatment system was a low temperature thermal desorption (LTTD) system.
- System included a feed system, rotary dryer, baghouse, wet quench, air mix chamber, and granulated activated carbon beds.
- Countercurrent rotary dryer, approximately 31 feet long and 6.5 feet in diameter, was direct-fired using a 32 million BTU/hr burner.
- Excavated soil was screened to 2 inches in diameter.
- System processed an average of 15 tons of soil/hr, with a typical soil exit temperature of 975°F.
- Off-gas was passed through a baghouse to remove particulates, cooled using flash evaporation of water in a spray tower quench chamber, passed through a mist eliminator, cooled in an on-line mix chamber where ambient air was added, and reheated prior to being sent to the carbon beds.
- Treated soil was combined with baghouse dust and water, discharged to a soil stacking area, and finally sent to a verification holding area for sampling.
EPA Region 4
61 Forsyth St., S.W.
Atlanta, GA 30303-8960
Telephone: (404) 562-8942
Organochlorine and organophosphorus pesticides including DDT, toxaphene, methyl parathion, and ethylene dibromide, as well as inorganics.
Pesticide formulation and packaging.
Type/Quantity of Media Treated:
Purpose/Significance of Application:
Use of thermal desorption to treat soil contaminated with pesticides and inorganic contaminants
Regulatory Requirements/Cleanup Goals:
- Cleanup goals were - DDT - 94 mg/kg; Toxaphene - 29 mg/kg; Methyl Parathion - 17 mg/kg; Ethylene Dibromide - 0.006 mg/kg
- Maximum stack gas total hydrocarbon (THC) levels were limited to 118 parts per million by volume (ppmv)
- Emissions had to meet state ambient air concentration levels for organic emissions
- Carbon beds removal efficiency >90%
- 10,424 tons of soil were treated in 18 batches
- All but one batch met the cleanup goals after initial treatment in the thermal desorber (the batch that was out of compliance met cleanup goals after the second treatment)
- Treated soil was backfilled on site
- There were no exceedances of the state ambient air limits
- Results of analyses of the removal efficiency of the carbon beds indicated that changeout of the carbon beds was not necessary
- Actual costs for this application - $1,058,230, including $566,184 for capital costs and $492,046 for O&M costs
- Unit cost of $102 per ton, based on 10,424 tons of treated soil
The THAN site, in Albany Georgia, operated from the 1950s until 1982 to formulate and package pesticides. Operations at the site resulted in contamination of soil and groundwater. The site was listed on the National Priorities List in 1989. During remedial investigations, it was discovered that the groundwater plume from the THAN parcel had migrated beneath an adjacent property owned by Larry Jones (Jones Property). The 5-acre Jones Property was the site of a former pesticide formulation and packaging facility (operated from 1964 to the 1970s). EPA divided the THAN site into two operable units (OU). OU1 addresses soil and groundwater from the original THAN site (western parcel). OU2 addresses soil contamination at the Jones Property (eastern parcel). This report addresses the remediation of OU2.
A record of decision (ROD) for OU2 was signed in 1996. The ROD specified excavation of contaminated soil and treatment using low temperature thermal desorption. Contaminants found in soil at the Jones Property included organochlorine and organophosphorus pesticides including DDT, toxaphene, methyl parathion, and ethylene dibromide, as well as inorganics. From October to November 1999, thermal desorption treated 10,424 tons of pesticide-contaminated soil to below cleanup goals. All but one batch met the cleanup goals after the initial treatment in the thermal desorber. The batch that was out of compliance met cleanup goals after the second treatment. All treated soil was backfilled on the site. The cost for thermal desorption at this site was $1,058,230 or $102 per ton of soil treated.