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Superfund Innovative Technology Evaluation (SITE)

 EPA/540/AR-92/002

Note: EPA no longer updates this information, but it may be useful as a reference or resource.

 

The Carver-Greenfield Process Dehydro-Tech Corporation Applications Analysis Report
August 1992

This report evaluates the Dehydro- Teech Corporation's Carver-Greenfield (C-G) Process and focuses on the technology's ability to separate waste mixtures into their constituent solid, organic, and water fractions while producing a solid residual that meets applicable disposal requirements. This report presents performance and economic data from the U.S. Environmental Protection Agency Superfund Innovative Technology Evaluation (SITE) demonstration and three case studies.

The C-G Process separates hazardous solvent-soluble organic contaminants (indigenous oil) from sludges, soils, and industrial wastes. The process involves adding waste to a solvent which extracts hazardous organics from contaminated solid particles and concentrates them in the solvent phase. In most applications, a food-grade hydrocarbon with a boiling point of about 400 "F is used as the solvent. Typically, 5 to 10 lb of solvent per lb of solids are used. First, the waste is added to the solvent in a mixing tank. The mixture is then transferred to a high-efficiency evaporator where the water is removed by vaporization. Next, the dry mixture is fed to a device that separates the solvent from the solid particles. Subsequent extractions of the dry solids may be made with clean recycled solvent, After final separation by centrifuging, any residual solvent is removed by hydroextraction, adesolventizing process that uses hot nitrogen gas or steam to separate the solvent from the solids. The final solids product typically contains low percentages of water (<5 %) and solvent (<1%). In the full-scale system, spent solvent containing indigenous oil is distilled to separate the indigenous oil from the solvent. The solvent is subsequently reused in the process. Products from the process include (1) clean dry solids, (2) a water product virtually free of solids and indigenous oil, and solvent and (3) extracted solvent-soluble compounds (indigenous oil).

The C-G Process demonstration was conducted as a part of the SITE Program at the Risk Reduction Engineering Laboratory's Releases Control Branch facility in Edison, New Jersey, using drilling mud waste from the PAB Oil Superfund site in Abbeville, LA. During the demonstration, the C-G Process pilot plant experienced no major operational problems. During startup and shakedown, the system exhibited minor, repairable problems.

The system generated a treated solids product that passed Toxicity Characteristic Leaching Procedure (TCLP) criteria for volatiles, semivolatiles, and metals. The system successfully separated the feed stream into its constituent water, indigenous oil, and solids fractions, and produced a dry final solids product containing less than 1% solvent.

Potential wastes that might be treated by this technology include industrial residues, Resource Conservation and Recovery Act wastes, Superfund wastes, and other wastes contaminated with organic compounds. The technology is especially applicable to wastes with high water content. A brief overview of the results from the C-G Process case studies, which discuss wastes treated by the technology, is presented in Appendix D.

Economic data indicate that the cost of treating wastes similar to those treated in the SITE demonstration, including disposal of residuals, is about $523 per wet ton of feed, of which $221 is C-G Process technology-specific and $302 is site-specific. Of the $302 per ton site-specific cost, about $240 per ton is for the incineration of indigenous oil separated from the feed.

Contact

Laurel Staley

Risk Mangement Research | Air and Climate Change Research | Water Research | Ecosystems Restoration Research | Land Risk Management Research | Technology: Sustainable Technologies Research, Environmental Technology Verification Program (ETV), and Technology Assessments

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