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 ELI ECO LOGIC INTERNATIONAL, INC.
(Thermal Desorption Unit)

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:

ELI Eco Logic International, Inc.'s (Eco Logic), thermal
desorption unit (TDU) is specially designed for use with Eco
Logic's gas-phase chemical reduction reactor.  For further 
information on the reduction reactor, see the profile in the
EPA-SITE program profiles document, 7th edition, Demonstration 
Program (Completed Projects Section).

The TDU consists of an externally-heated bath of molten tin metal
(heated with propane) in a hydrogen gas atmosphere.  Tin is used
for several reasons:  tin and hydrogen are non-reactive; tin's
density allows soils to float on the molten bath; molten tin is a
good fluid for heat transfer; tin is nontoxic in soil; and tin is
used as a bath medium in the manufacture of plate glass.

Contaminated soil is conveyed into the TDU feed hopper, where an
auger feeds the soil into the TDU.  A screw feeder provides a gas
seal between the outside air and the hydrogen atmosphere inside
the TDU.  The auger's variable speed drive provides feed rate
control.  Soil inside the TDU floats on top of the molten tin and
is heated to 600 degrees Celsius, vaporizing the water and
organic material.  Decontaminated soil is removed from the tin
bath into a water-filled quench tank.  The water in the quench
tank provides a gas seal between the TDU's hydrogen atmosphere
and the outside air.  A scraper mechanism removes desorbed soil
from the quench tank into drums.

After desorption from the soil, the organic contaminants are
carried from the TDU to Eco Logic's proprietary gas-phase
reduction reactor.  In the reactor, the organic contaminants
undergo gas-phase chemical reduction reactions with hydrogen at
elevated temperatures.  This reaction converts organic and
chlorinated organic contaminants into a hydrocarbon-rich gas
product.  After passing through a scrubber, the gas product's
primary components are hydrogen, nitrogen, methane, carbon
monoxide, water vapor, and other lighter hydrocarbons.  Most of
this gas product recirculates into the process, while excess gas
can be used as supplemental fuel or compressed for later analysis
and reuse as supplemental fuel.  Refer to the profile of the Eco
Logic gas-phase reduction process for a more complete
description.

WASTE APPLICABILITY:

The Eco Logic TDU, when used with the gas-phase chemical
reduction reactor, is designed to desorb soils and sludges
contaminated with hazardous organic contaminants such as poly-
chlorinated biphenyls (PCB), polynuclear aromatic hydrocarbons,
chlorinated dioxins and dibenzofurans, chlorinated solvents,
chlorobenzenes, and chlorophenols.  The combined technologies can
easily handle wastes with high water content since water is a
good source of hydrogen.

STATUS:

In October and November 1992, a SITE demonstration of the Eco
Logic Process, including the TDU, was conducted at the
Middleground Land-fill in Bay City, Michigan, under a Toxic Sub-
stances Control Act research and development permit.  The formal
test program consisted of processing soil containing an average
627 parts per million (ppm) PCBs.

Further research and development over the last 18 months has
focused on optimizing the process for commercial operations and
improving the design of the soil/sediment processing unit. 
According to the vendor, the TDU design cur-rently under
construction has achieved excellent results in laboratory-scale
tests, with soils and sediments desorbed from high ppm to percent
levels down to low parts per billion levels.

A commercial-scale unit of the gas-phase chemical reduction
process, combining the reductive reactor and TDU (SE-25), has
been constructed with a design capacity of 100-300 tons per day
of contaminated soil or sediment and 20 tons per day of PCB
askarel fluid.  The cost of processing these waste streams is
estimated at $400 and $2,000 per ton, respectively.  The first
SE25 system has been exported to Australia for the destruction of
200 tons of obsolete pesticides.  A second  SE25 system will be
ready for commercial use in North America by the end of 1994.

DEMONSTRATION RESULTS:

During testing in Bay City, Michigan, the Eco Logic TDU achieved
the following:

>  Destruction efficiencies (DE) for PCBs from the soil of
   93.5 percent in run 1 and 98.8 percent in run 2.
   DE for hexachlorobenzene (a tracer com-pound) from the
   soil of 72.13 percent in run 1 and 99.998 percent in run
   2.
   
>  PCB destruction and removal efficiencies (DRE) for the
   combined TDU and reduction reactor system of 99.9999
   percent for run 1 and 99.997 percent for run 2. PCB
   throughput for run 2 was below the target value, so a DRE
   of 99.9999 percent could not be achieved.

FOR FURTHER INFORMATION:

EPA PROJECT MANAGER:
Gordon Evans
U.S. EPA
Risk Reduction Engineering Laboratory
26 West Martin Luther King Drive
Cincinnati, OH 45268
513-569-7684
Fax: 513-569-7620

TECHNOLOGY DEVELOPER CONTACT:
Jim Nash
ELI Eco Logic International Inc.
143 Dennis Street
Rockwood, Ontario, Canada
N0B 2K0
519-856-9591Fax: 519-856-9235
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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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