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STATUS OF EPA/DOE MOU TECHNICAL WORKGROUP ACTIVITIES: HG WASTE TREATMENT
Citation:
Randall*, P M. STATUS OF EPA/DOE MOU TECHNICAL WORKGROUP ACTIVITIES: HG WASTE TREATMENT. Presented at EPA/DOE Memorandum of Understanding on Mixed Waste Treatment Workshop, Salt Lake City, UT, 4/27/2001.
Description:
EPA's Land Disposal Restrictions program currently has technology-specific treatment standards for hazardous wastes containing greater than or equal to 260ppm total mercury (Hg) (i.e., high Hg subcategory wastes). The treatment standards specify RMERC for high Hg subcategory wastes and IMERC if the high Hg subcategory wastes contain organics. RMERC requires retorting or roasting in a thermal processing unit, while IMERC specifies incineration. Both of these standards are based on the premise of recovering the Hg for recycle. In the case of radioactively-contaminated Hg, when the Hg is receovered, it is typically still radioactive and therefore cannot be recycled. EPA requires that this recovered radioactively contaminated Hg undergo additional treatment, specifically amalgamation, prior to disposal. The DOE TRU and Mixed Waste Focus Area (TMFA) and the Mg Working Group (HgWG) chartered under the TMFA are working with EPA to validate technologies that can directly treat radioactively contaminated high Hg subcategory wastes without removin the Hg from the waste. To date under this program a waste soil brom Brookhaven National lab (BNL) containing approximately 4,800 ppm of Hg and radioactive contaminants has been successfully treated by several different vendors to meet a Hg Toxic Characteristic Leaching Procedure (TCLP) treatment goal of 0.025 mg/l or less. These treated waste forms are now undergoing additional evaluations using new analytical protocols, developed by Vanderbilt University. The data generated will be compared to the standard TCLP results. These new protocols provide another mehodology to determine how the treated waste form will behave in a variety of disposal environments. To supplement the data on treatment of soils, EPA needs additional data for stabilization of high Hg subcategory waste sludges. A new project began to treat a Hg surrogate sample at 5000 ppm. BNL will provide support to the EPA and TMFA efforts to validate immobilization processes by preparing samples for evaluation. The samples will be prepared using the SPSS process on a simulated, non-radioactive sludge contaminated with five forms of Hg, including elemental. The University of Cincinnati (UC) will supply ingredients to BNL for the simulated sludge. After BNL prepares the samples, they will be returned for testing under proposed new analytical protocols as well as the standard TCLP method. The data gathered from the demonstration of treatment of this sludge should then provide EPA with enough information to support a revision to allow stabilization of high Hg subcategory wastes. Also, EPA will use the results in their efforts to revise and LDR treatment standards for Hg-bearing hazardous wastes.