Process for the Solvent Extraction for the Radiolysis and Dehalogenation of Halogenated Organic Compounds in Soils, Sludges, Sediments, and Slurries

Abstract

A process of extracting halogenated organic compounds, and particularly PCBs, from soil, sediment, slurry, sludge and dehalogenating the compounds contacts a contaminated soil sample with an extraction medium of a mixture of an alkane and a water miscible alcohol. The organic compounds dissolve in the extraction medium which is separated from the soil by passing water upwardly through the soil. The extraction medium floats to the surface of the water and is separated. Thereafter, the extraction medium containing the halogenated organic contaminants is subjected to ionizing radiation to radiolytically dehalogenate the compounds.

Description

CROSS-REFERENCE TO RELATED APPLICATION [0001] This application is a continuation application of U.S. application Ser. No. 10 / 386,181, filed Mar. 11, 2003, which is a divisional application of U.S. application Ser. No. 09 / 637,005 filed Aug. 14, 2000, now U.S. Pat. No. 6,568,879, which is a divisional application of U.S. application Ser. No. 09 / 168,894 filed Oct. 9, 1998, now U.S. Pat. No. 6,132,561 which claims the benefit of U.S. Provisional Application No. 60 / 062,820 filed Oct. 13, 1997.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT [0002] The U.S. government may have certain rights in this application pursuant to Contract No. DE-AC07-94ID13223 between the U.S. Department of Energy and Idaho National Engineering Laboratory.APPENDIX [0003] Not applicable. FIELD OF INVENTION [0004] The present invention relates to a process for extracting halogenated organic compounds, and particularly poly-chlorinated-biphenyls (PCB's) from soils, sludges, sediments and slurries, an...

AI Technical Summary

Benefits of technology

[0017] A further object of the present invention is to provide a method of floating the desorbed halogenated compounds and alkane-alcohol mixture to the top of a contaminated volume of solid particulate material that can include soil, sediment, slurry, or sludge so that the alkane-alcohol mixture and contaminant can be removed from the solid particulate material. Thereafter, the mixture containing the contaminants is collected and subjected to ionizing radiation so that radiolytic dehalogenation of the halogenated compounds occurs.

[0018] Another object of the present invention is to provide a method for subjecting the halogenated compounds to ionizing radiation with continuous mixing so that a highly uniform radiation dose is applied with high utilization efficiency of the radiation source's output power. Still another object of the present invention is to provide a method for the efficient radiolytic dehalogenation of the halogenated organic compounds obtained by a solvent extraction / flotation method.

Problems solved by technology

PCB's and other halogenated organic compounds are hazardous contaminants in soils, sludges, sediments and slurries.

While the manufacture of PCB's is now prohibited in the United States, the size of the environmental burden in water, sediments, soil, disposal sites, and in electrical transformers is large.

Moreover, as a result of manufacturing operations, spills and the disposal of electrical equipment, large areas of soil and sediment are also contaminated with PCB's.

However, it suffers from high cost and public resistance because of residues and stack emissions that may be contaminated with hazardous products of incomplete combustion or combustion by-products.

Biological treatment of PCB's is limited to relatively low PCB concentrations, may act very slowly, and may generate hazardous treatment by-products.

Also, biological treatment has not been proven effective for all PCB congeners.

These techniques may have high cost and do not generally avoid the environmental and practical disadvantages of thermal or chemical destruction methods.

Moreover, toxic oxidation byproducts such as dioxin and dibenzofurans are not generated by the reduction reaction in organic solutions.

Although the radiolytic dechlorination of PCB's in solution has been well proven, the radiolytic dechlorination of PCB's in soil may require large doses.

The large doses lead to higher cost for the treatment process.

This process has the disadvantage of requiring large doses of radiation.

Both of these approaches result in higher cost for treatment.

Flipping the target to be treated is most commonly performed on solid targets and has not been effectively done with multi-component liquids except in recirculating systems in which the material makes many passes.

The lack of an inexpensive and easily implemented means to obtain dose uniformity has resulted in a higher cost of treatment.

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