&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

-------
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

-------