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 RESOURCES CONSERVATION COMPANY
(B.E.S.T. Solvent Extraction Technology)

This vendor is participating in the EPA Superfund Innovative 
Technology Evaluation (SITE) Program.  The following technology 
profile has been reproduced from the SITE Technology Profile 
document, 7th edition.  The SITE profile has been supplemented by 
MVA Consulting Inc. using information obtained from the vendor or 
from other SITE publications, referenced at the end of this file. 

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TECHNOLOGY DESCRIPTION:

Solvent extraction treats sludges, sediments, and soils
contaminated with a wide range of hazardous contaminants
including polychlorinated biphenyls (PCB), polynuclear aromatic
hydrocarbons (PAH), pesticides, and herbicides.  The waste matrix
is separated into three fractions:  oil, water, and solids.  As
the fractions separate, organic contaminants are concentrated in
the oil fraction.  For example, PCBs are concentrated in the oil
fraction, while metals are separated into the solids fraction. 
The volume and toxicity of the original waste is thereby reduced,
and the concentrated waste streams can be efficiently treated for
disposal.

The B.E.S.T. technology is a mobile solvent extraction system
that uses amines (usually triethylamine) to separate organics
from soils and sludges.  Triethylamine is hydrophobic above 20
degrees Celsius (oC) and hydrophilic below 20 ¿C.  This property
allows the process to extract both aqueous and nonaqueous compounds 
by simply changing the solvent's temperature.

Because triethylamine is flammable in the presence of oxygen, the
treatment system must be sealed from the atmosphere and operated
under a nitrogen blanket.  Before treatment, the waste material's
pH must be raised to greater than 10 so that triethylamine may be
conserved and recycled.  The pH may be adjusted by adding sodium
hydroxide.  Pretreatment also includes screening the waste to re-
move particles larger than 1 inch in diameter.

The B.E.S.T. process begins by mixing and agitating the cold
solvent and waste in a cold extraction tank (see figure below). 
Solids from the cold extraction tank are then transferred to the
extractory dryer vessel.  Hydrocarbons and water in the waste
simultaneously solubilize with the triethylamine, creating a
homogeneous mixture.  As the solvent breaks the oil-water-solid
emulsions in the waste, the solids are released and settle by
gravity.  The solvent mixture is decanted from the solids and
centrifuged to remove fine particles.

The solvent-oil-water mixture is then heated.  As the mixture's
temperature increases, the water separates from the organics and
solvent.  The organics-solvent fraction is decanted and sent to a
solvent evaporator, where the solvent is recycled.  The organics
are discharged for recycling or disposal.  The water passes to a
steam stripping column where residual solvent is recovered for
recycling.  The water is typically discharged to a local
wastewater treatment plant.

The B.E.S.T. technology is modular, allowing for on-site
treatment.  The process significantly reduces the hydrocarbon
concentration in the solids.  B.E.S.T. also concentrates the
contaminants into a smaller volume, allowing for efficient final
treatment and disposal.

WASTE APPLICABILITY:

The B.E.S.T. technology can remove hydro-carbon contaminants,
such as PCBs, PAHs, pesticides, and herbicides from sediments,
sludges, or soils.  System performance can be influenced by the
presence of detergents and emulsifiers, low pH materials, and
reactivity of the organics with the solvent.

STATUS:

The B.E.S.T. technology was accepted into the SITE Demonstration
Program in 1987.  The SITE demonstration was completed in July
1992 at the Grand Calumet River site in Gary, Indiana.  The
following reports are available from EPA:

>  Applications Analysis Report
     (EPA/540/AR-92/079)

>  Technology Evaluation Report - Vol I
   (EPA/540/R-92/079a)

>  Technology Evaluation Report - Vol II,
   Part 1 (EPA/540/R-92/079b)

>  Technology Evaluation Report - Vol II,
   Part 2 (EPA/540/R-92/079c)

>  Technology Evaluation Report - Vol II,
   Part 3 (EPA/540/R-92/079d)

>  Technology Demonstration Summary
   (EPA/540/SR-92/079)

The first full-scale B.E.S.T. unit was used at the General
Refining Superfund site in Garden City, Georgia.  Solvent
extraction is the selected remedial action at the Ewan Property
site in New Jersey, the Norwood PCBs site in Massachusetts, and
is also the preferred alternative at the F. O'Connor site in
Maine.

The demonstration showed that the B.E.S.T. process could remove
greater than 99 percent PCBs (treated solids contained less than
2 milligrams per kilogram PCBs) found in river sediments without
using mechanical dewatering equipment.  Comparable removal
efficiencies were noted for PAHs.

FOR FURTHER INFORMATION:

EPA PROJECT MANAGER:
Mark Meckes
U.S. EPA
Risk Reduction Engineering Laboratory
26 West Martin Luther King Drive
Cincinnati, OH  45268
513-569-7348
Fax: 513-569-7676

TECHNOLOGY DEVELOPER CONTACT:
Lanny Weimer
Resources Conservation Company
3630 Cornus Lane
Ellicott City, MD  21042
410-596-6066
Fax: 410-465-2887
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Sources of information in this profile:

EPA Superfund Innovative Technology Evaluation Program 
        Technology Profiles Seventh Edition, November 1994. 
        EPA/540/R-94/526.


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