7 Matching Results

Search Results

Advanced search parameters have been applied.

Evaluation of ground freezing for environmental restoration at waste area grouping 5, Oak Ridge National Laboratory, Oak Ridge, Tennessee

Description: A study to evaluate the feasibility of using ground freezing technology to immobilize tritium contaminants was performed as part of the Waste Area Grouping (WAG) 6 Technology Demonstrations initiated by the WAG 6 Record of Agreement. The study included a review of ground freezing technology, evaluation of this technology for environmental restoration, and identification of key technical issues. A proposed ground freezing demonstration for containment of tritium at a candidate Oak Ridge National Laboratory site was developed. The planning requirements for the demonstration were organized into seven tasks including site selection, site characterization, conceptual design, laboratory evaluation, demonstration design, field implementation, and monitoring design. A brief discussion of each of these tasks is provided. Additional effort beyond the scope of this study is currently being directed to the selection of a demonstration site and the identification of funding.
Date: September 1, 1995
Creator: Gates, D.D.
Partner: UNT Libraries Government Documents Department

Mercury removal from solid mixed waste

Description: The removal of mercury from mixed wastes is an essential step in eliminating the temporary storage of large inventories of mixed waste throughout the Department of Energy (DOE) complex. Currently thermal treatment has been identified as a baseline technology and is being developed as part of the DOE Mixed Waste Integrated Program (MWIP). Since thermal treatment will not be applicable to all mercury containing mixed waste and the removal of mercury prior to thermal treatment may be desirable, laboratory studies have been initiated at Oak Ridge National Laboratory (ORNL) to develop alternative remediation technologies capable of removing mercury from certain mixed waste. This paper describes laboratory investigations of the KI/I{sub 2} leaching processes to determine the applicability of this process to mercury containing solid mixed waste.
Date: December 31, 1994
Creator: Gates, D.D.; Morrissey, M.; Chava, K.K. & Chao, K.
Partner: UNT Libraries Government Documents Department

Chemical oxidation of volatile and semi-volatile organic compounds in soil

Description: Subsurface contamination with fuel hydrocarbons or chlorinated hydrocarbons is prevalent throughout the Department of Energy (DOE) complex and in many sites managed by the Environmental Protection Agency (EPA) Superfund program. The most commonly reported chlorinated hydrocarbons (occurring > 50% of DOE contaminated sites) were trichloroethylene (TCE), 1, 1, 1,-trichloroethane (TCA), and tetrachloroethylene (PCE) with concentrations in the range of 0.2 {mu}g/kg to 12,000 mg/kg. The fuel hydrocarbons most frequently reported as being present at DOE sites include aromatic compounds and polyaromatic compounds such as phenanthrene, pyrene, and naphthalene. The primary sources of these semi-volatile organic compounds (SVOCs) are coal waste from coal fired electric power plants used at many of these facilities in the past and gasoline spills and leaks. Dense non-aqueous phase liquids (DNAPLs) can migrate within the subsurface for long periods of time along a variety of pathways including fractures, macropores, and micropores. Diffusion of contaminants in the non-aqueous, aqueous, and vapor phase can occur from the fractures and macropores into the matrix of fine-textured media. As a result of these contamination processes, removal of contaminants from the subsurface and the delivery of treatment agents into and throughout contaminated regions are often hindered, making rapid and extensive remediation difficult.
Date: June 1, 1995
Creator: Gates, D.D.; Siegrist, R.L. & Cline, S.R.
Partner: UNT Libraries Government Documents Department

The removal of mercury from solid mixed waste using chemical leaching processes

Description: The focus of this research was to evaluate chemical leaching as a technique to treat soils, sediments, and glass contaminated with either elemental mercury or a combination of several mercury species. Potassium iodide/iodine solutions were investigated as chemical leaching agents for contaminated soils and sediments. Clean, synthetic soil material and surrogate storm sewer sediments contaminated with mercury were treated with KI/I{sub 2} solutions. It was observed that these leaching solutions could reduce the mercury concentration in soil and sediments by 99.8%. Evaluation of selected posttreatment sediment samples revealed that leachable mercury levels in the treated solids exceeded RCRA requirements. The results of these studies suggest that KI/I{sub 2} leaching is a treatment process that can be used to remove large quantities of mercury from contaminated soils and sediments and may be the only treatment required if treatment goals are established on Hg residual concentrations in solid matrices. Fluorescent bulbs were used to simulate mercury contaminated glass mixed waste. To achieve mercury contamination levels similar to those found in larger bulbs such as those used in DOE facilities a small amount of Hg was added to the crushed bulbs. The most effective agents for leaching mercury from the crushed fluorescent bulbs were KI/I{sub 2}, NaOCl, and NaBr + acid. Radionuclide surrogates were added to both the EPA synthetic soil material and the crushed fluorescent bulbs to determine the fate of radionuclides following chemical leaching with the leaching agents determined to be the most promising. These experiments revealed that although over 98% of the dosed mercury solubilized and was found in the leaching solution, no Cerium was measured in the posttreatment leaching solution. This finding suggest that Uranium, for which Ce was used as a surrogate, would not solubilize during leaching of mercury contaminated soil or glass.
Date: July 1, 1995
Creator: Gates, D.D.; Chao, K.K. & Cameron, P.A.
Partner: UNT Libraries Government Documents Department

Removal of mercury from solids using the potassium iodide/iodine leaching process

Description: Potassium iodide (KI) and iodine (I{sub 2}) leaching solutions have been evaluated for use in a process for removing mercury from contaminated mixed waste solids. Most of the experimental work was completed using surrogate waste. During the last quarter of fiscal year 1995, this process was evaluated using an actual mixed waste (storm sewer sediment from the Oak Ridge Y-12 Site). The mercury content of the storm sewer sediment was measured and determined to be approximately 35,000 mg/kg. A solution consisting of 0.2 M I{sub 2} and 0.4 M KI proved to be the most effective leachant used in the experiments when applied for 2 to 4 h at ambient temperature. Over 98% of the mercury was removed from the storm sewer sediment using this solution. Iodine recovery and recycle of the leaching agent were also accomplished successfully. Mathematical model was used to predict the amount of secondary waste in the process. Both surrogate waste and actual waste were used to study the fate of radionuclides (uranium) in the leaching process.
Date: December 1, 1997
Creator: Klasson, K.T.; Koran, L.J. Jr.; Gates, D.D. & Cameron, P.A.
Partner: UNT Libraries Government Documents Department

Mercury removal from liquid and solid mixed waste

Description: Based on bench-scale laboratory experiments, the following conclusions were reached: Sulfur-impregnated, activated, carbon pellets (Mersorb) can be used to remove mercury (Hg{sup 2+}) to below EPA`s toxic characteristic level (0.2 mg/L). Mersorb works under acid conditions (pH 2) but its capacity is reduced by approximately 50% compared with neutral conditions. Competing ions present in the target waste stream reduced the Mersorb capacity by 50%. Mersorb appears to be economical compared with leading ion exchange resin. KI/I{sub 2} leaching solution can be used to remove up to 99% of Hg in contaminated soil and glass. KI/I{sub 2} leaching solution worked well with several mercury species, including Hg{sup 0}, HgO, HgS, and HgCl{sub 2}. KI/I{sub 2} leaching solution worked well with a wide variety of initial mercury concentrations. Radionuclide surrogate studies suggested that uranium will not partition into KI/I{sub 2} leaching solutions. Cesium may partition into the KI/I{sub 2} leaching solution because of the high solubility of cesium salts.
Date: April 1, 1995
Creator: Gates, D.D.; Klasson, K.T.; Corder, S.L.; Cameron, P.A.; Perona, J.J. & Chao, K.K.
Partner: UNT Libraries Government Documents Department

In Situ Remediation Integrated Program. In situ physical/chemical treatment technologies for remediation of contaminated sites: Applicability, developing status, and research needs

Description: The U.S. Department of Energy (DOE) In Situ Remediation Integrated Program (ISR IP) was established in June 1991 to facilitate the development and implementation of in situ remediation technologies for environmental restoration within the DOE complex. Within the ISR IP, four subareas of research have been identified: (1) in situ containment, (2) in situ physical/chemical treatment (ISPCT), (3) in situ bioremediation, and (4) subsurface manipulation/electrokinetics. Although set out as individual focus areas, these four are interrelated, and successful developments in one will often necessitate successful developments in another. In situ remediation technologies are increasingly being sought for environmental restoration due to the potential advantages that in situ technologies can offer as opposed to more traditional ex situ technologies. These advantages include limited site disruption, lower cost, reduced worker exposure, and treatment at depth under structures. While in situ remediation technologies can offer great advantages, many technology gaps exist in their application. This document presents an overview of ISPCT technologies and describes their applicability to DOE-complex needs, their development status, and relevant ongoing research. It also highlights research needs that the ISR IP should consider when making funding decisions.
Date: June 1, 1994
Creator: Siegrist, R. L.; Gates, D. D.; West, O. R.; Liang, L.; Donaldson, T. L.; Webb, O. F. et al.
Partner: UNT Libraries Government Documents Department