&EPA
United States
Environmental Protection
Agency
EPA/540/MR-92/002
February 1992
SUPERFUND INNOVATIVE
TECHNOLOGY EVALUATION
Demonstration Bulletin
The Carver-Greenfield Process
Dehydro-Tech Corporation
TECHNOLOGY DESCRIPTION: The Carver-Greenfield
(C-G) Process (Figure 1) is a physical process that
separates hazardous oil-soluble organic contaminants
from sludges, soils, and non-aqueous liquids. The
process involves adding to the waste a "carrier" oil,
which removes hazardous organics from contaminated
solid particles and concentrates them in the oil phase.
In most applications, a food-grade oil with a boiling
point of about 400°F is used as the carrier oil.
Typically, 5 to 10 pounds of carrier oil per pound of
solids is used. First, carrier oil is added to the waste in
a mixing tank. The mixture is then transferred to a
high-efficiency evaporator where the water is removed.
Next, the dry mixture is fed to a centrifuge that
separates the oil from the solid particles. After final
centrifuging, any residual carrier oil is removed by
hydroextraction, a de-oiling process that uses hot
nitrogen gas to separate oil from solids. The final
solids product typically contains low percentages of
water and oil. In the full-scale system, recirculated oil
is distilled to recover carrier oil, which is subsequently
reused.
By-products from the process include: (1) a
concentrated mixture of the extracted oil-soluble
compounds, (2) a water product virtually free of solids
and oils, and (3) a clean, dry solid.
WASTE APPLICABILITY: The C-G Process can be
applied to wastes containing water and organic
contaminants. Commercial C-G Process plants have
been used to treat materials with high water content,
Vent to
Treatment
\
F«ed ' • f»
Sludge/Soil/ J^
Waste Vacuum
Pump
Condenser
Carrier Oil Vapor-and Steam
o
Dry
Solids
Product
i r
T m Q Recovered ,
Light
O Oil Soluble
Components
Extracted
O OD Soluble
Compofivnts
^ \j \ju i^wiwwiw
Compofivnts
\
Figure 1. Flow Diagram of the Carver-Greenfield Process
^ Printed on Recycled Paper
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such as meat rendering waste, municipal sewage
sludge, paper mill sludge, brewery treatment plant
sludge, pharmaceutical plant waste, and leather dyeing
waste. The system cannot process large particles. If
necessary, waste feed should be pretre$ted using a
grinder to a maximum particle size of about 1/4 inch.
The process can treat wastes with oil-soluble contents
ranging from parts per million (ppm) levels up to 75
percent. Because the process is based on a dewatering
technology, it can treat waste streams containing up to
99 percent water.
DEMONSTRATION RESULTS: The process was
demonstrated on drilling muds excavated from the PAB
Oil Superfund site in Abbeville, Louisiana. The
demonstration was conducted in August 1991 at a
U.S. EPA research facility in Edison, New Jersey. A
trailer-mounted C-G unit treated about 640 pounds of
drilling mud wastes in two separate test runs ,_..
Table 1. Demonstration Results
Test Run #1
Operation of the system:
• generated a treated solids product that passed
Toxicity Characteristic Leaching Procedure (TCLP)
criteria for volatiles, semivolatiles, and metals
• successfully separated the feed stream into its
constituent water, oil, and solids fractions
• removed 94 to 96 percent of the oil from the
solid fraction (see Table 1)
• produced a dry final solids product containing less
than 1 percent carrier oil
FOR FURTHER INFORMATION:
EPA PROJECT MANAGER:
.Laurel. Staley, . _^
U.S. EPA
Risk Reduction Engineering Laboratory
26 West Martin Luther King Drive
Cincinnati, Ohio 45268
513-569-7863
FTS: 684-7863
Test Run #2
Parameter
Solids
Indigenous Oil
Water
Carrier Oil
Feed, %
52.4
17.5
21.8
N/D1
Solids
Product, %
96.6
1.45
N/D1
0.93
Feed, %
52.4
7.28
34.7
N/D1
Solids
Product, %
98.3
0.85
N/D1
0.89
Percent Oil Removal2 95.9
1N/D: Not Detected.
2Percent removal is based on the solids fraction of the influent feed.
94.3
United States
Environmental Protection
Agency
Center for Environmental
Research Information
Cincinnati OH 45268
BULK RATE
POSTAGE & FEES PAID
EPA
PERMIT No. G-35
Official Business
Penalty for Private Use $300
EPA/540/MR-92/002
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