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

The present invention provides a process for extracting halogenated organic compounds from contaminated materials, such as soil, using a solvent extraction method that is compatible with radiolytic dehalogenation. The process involves using a mixture of short chain alkanes and a radiolytically advantageous solvent to desorb the halogenated compound from the soil. The solvent is then separated from the soil and subjected to ionizing radiation to cause dehalogenation of the halogenated compounds. The invention also provides an apparatus for delivering a uniform ionizing radiation dose to a fluid. The technical effects of the invention include efficient removal of halogenated compounds from contaminated materials and the use of a solvent extraction method that does not interfere with radiolytic dehalogenation.

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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