Technology:
- Thermal Desorption (ex situ)
- High vacuum, indirectly heated rotary retort that removes volatiles from non-volatile matrices
- Air and sweep gases eliminated from retort, minimizing gas exhausted to atmosphere
- Vacuum of at least 25 inches Hg and moderate temperature maintained during operation
- Heat indirectly applied within an insulated firebox fueled by natural gas, diesel oil, or propane
- Following drying phase, temperature raised to a target value, typically in the range of 600-750°C, and held there for a predetermined period
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Cleanup Authority:
Not identified
Contacts:
Technical Project Manager
Jim Brower
Brookhaven National Laboratory
(631) 433-7513 (phone)
(631) 344-6134 (fax)
E-mail: brower@bnl.gov | DOE-ID Program Director
William Owca
Transuranic and Mixed Waste Focus Area Manager
U.S. Department of Energy
Idaho Operations Office
850 Energy Drive
Idaho Falls, Idaho 83401-1563
(208) 526-1983 (phone)
(208) 526-5964 (fax)
E-mail: owcawa@id.doe.gov |
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Contaminants:
Mercury |
Waste Source:
Contaminated soil retrieved from remedial excavation activities of the Animal/Chemical Pits on site and mixed waste from various DOE operations |
Type/Quantity of Media Treated:
Mixed waste; 3,050 lbs, consisting of soil and waste carcasses |
Purpose/Significance of Application:
To evaluate effectiveness of using the SepradyneTM-Raduce system for removing and recovering mercury from a mixed waste matrix |
Regulatory Requirements/Cleanup Goals:
Total mercury concentrations in residuals below 10 ppm
- Universal treatment standards (UTS) of 0.025 mg/L leachable mercury as determined by TCLP tests
- MACT standard of 40 µg/m3 for mercury emissions |
Results:
System treated mixed waste with a maximum mercury concentrations of 5,510 ppm.
- Final residuals from the process had total mercury levels ranging from 0.55 to 8 ppm
- Leachable mercury levels were 0.008 mg/L or less based on TCLP tests
- Emission of mercury averaged between 1 and 14 µg/m3 throughout system operation |
Cost Factors:
Based on the demonstration, the projected unit cost to treat waste at full-scale using the Sepradyne™-Raduce system is approximately $0.90 per lb. This estimate is based on a processing rate of 1,000 lb/hr, and assumes operation at full capacity over 10 years. Capital costs are estimated to be $1,500,000. The unit cost includes disposal costs of the associated waste streams (estimated to be $1,000/m3 for solids, $0.10/gal for wastewater, and $25/gal for organics), and excludes decontamination and decommissioning costs. |
Description:
BNL is a DOE facility located in Upton, New York. The Laboratory conducted remedial excavation activities of the Animal/Chemical Pits on site in 1997, generating mixed waste with elevated concentrations of mercury. A field demonstration using the SepradyneTM-Raduce system was conducted to evaluate the effectiveness of the system in removing and recovering mercury from the mixed waste matrix.
The field demonstration involved treating 3,050 lbs of mixed waste consisting primarily of soil and waste carcasses. The goals of the demonstration were to reduce total mercury concentrations in the treatment residuals to below 10 ppm, reduce leachable mercury concentrations to below 0.025 mg/L TCLP, and reduce air emissions of mercury to below 40 µg/m3. Analysis of the data after the demonstration was complete showed that total mercury levels ranged from 0.55 to 8 ppm, TCLP leachable mercury levels were 0.008 mg/L or less, and air emissions of mercury averaged between 1 and 14 µg/m3 throughout operation of the system. These data indicated that the project goals and regulatory requirements were met. The projected unit cost for treating mercury-containing mixed waste using the Sepradyne™-Raduce system is $0.90 per lb, assuming a processing rate of 1,000 lb/hr and full-scale operation over a period of 10 years. This cost includes disposal costs and excludes decontamination and decommissioning costs. Data collected during the demonstration showed that the process was able to provide a final product with a 23% weight reduction. Based on visual inspection, the volume reduction was estimated at approximately 40 to 50%. |
