Technology:
Stabilization
- Stabilization reagents involved addition of water and then cement to form a grout mixture; the mixture was then blended with sodium metasilicate and cured for two days
- Bench- and pilot-scale tests were conducted, at high and low waste loadings
- Pilot-scale tests were conducted in drums using a vertical in-drum mixer
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Cleanup Authority:
Not identified
Contacts:
Thomas B. Conley
Oak Ridge National Laboratory
Telephone: (423) 241-1839
Fax: (423) 241-2973
E-mail: tbc@ornl.gov
William Owca
DOE Idaho Operations Office
Telephone: (208) 526-1983
Fax: (208) 526-5964
E-mail: owcawa@inel.gov |
Contaminants:
Heavy metals, Volatile Organics, and Radionuclides
- Mercury concentration was 230 mg/kg; TCLP 0.0399 to 0.184 mg/L
- DCE concentration was 11,000 mg/kg, vinyl chloride 220 mg/kg, methylene chloride 12,000 mg/kg
- Radionuclides included plutonium and strontium |
Waste Source:
Nuclear processing operations |
Type/Quantity of Media Treated:
Sludge and Laboratory Wastes
- Four 55-gallon drums containing 1,253 lbs of sludge
- Three containers of lab packs from analysis of the sludge |
Purpose/Significance of Application:
Demonstrate stabilization of low level mercury in radioactive wastes |
Regulatory Requirements/Cleanup Goals:
- Land Disposal Restrictions for heavy metals (such as mercury - 0.025 mg/L) and organics
- Envirocare Waste Acceptance Criteria (WAC) for disposal |
Results:
- At low waste loadings, mercury concentrations were reduced to values ranging from 0.00127 to 0.0169 mg/L, below the LDR standard of 0.025 mg/L; at high waste loadings, mercury was reduced to values ranging from 0.0024 to 0.0314 mg/L one sample contained mercury above the LDR standard
- Several organic compounds and radionuclides were higher than the LDR standards or Envirocare WAC after treatment, including 1,1,1-trichloroethane, 1,1-dichloroethane, methylene chloride, lindane, DDE, heptachlor epoxide, and methoxychlor, strontium, and americium
- The vendor indicated that these results re-emphasized the importance of accurate characterization data; the high levels of organics were not expected based on the original characterization data provided by LANL
- Bench-scale tests showed mercury met LDR level in all 3 low load and 2 of 3 high load samples |
Cost Factors:
- Projected costs for a full-scale stabilization system using this technology were not developed |
Description:
Sludge was generated at the Phase Separation Pits of the TA 35 facility of the Los Alamos National Laboratory (LANL) by addition of a caustic solution to the condensate and particulates removed from laboratory fume hood exhausts by the phase separators. The sludge and laboratory wastes from analysis of the sludge, were a mixed waste due to the presence of radionuclides, heavy metals, and RCRA-listed organic compounds.
Bench- and pilot-scale tests of the GTS Duratek process were conducted to stabilize the contaminants in the sludge and laboratory wastes. The GTS Duratek process includes addition of water, cement, and sodium metasilicate. The stabilized product met the LDR standard for mercury in all but one high load test sample. However, several VOCs, pesticides, herbicides, and radionuclides did not meet the LDR standards or Envirocare WAC after treatment. This result was attributed to inaccurate characterization data of the waste streams, which did not show the relatively high levels of organics. |
