United States
Environmental Protection
Agency
SUPERFUND INNOVATIVE
TECHNOLOGY EVALUATION
Demonstration Bulletin
Minergy Glass Furnace Technology
Minergy Corporation
Technology Description: The Glass Furnace Technology (GFT)
was developed by Minergy Corporation (Minergy), of Waukesha,
Wisconsin. Minergy originally developed vitrification technologies
to process paper mill sludge into glass aggregate that could be
sold as a commercial product. Minergy modified a standard glass
furnace to melt and treat river sediment containing polychlori-
nated biphenyls (PCBs). The technology was evaluated during a
U.S. Environmental Protection Agency Superfund Innovative Tech-
nology Evaluation (SITE) Program demonstration at the Minergy
facility in Winneconne, Wisconsin, in August 2001. The SITE
program evaluated the technology's ability to treat sediment
containing PCBs and metals to form a product with beneficial
reuse. Because the GFT melter requires the river sediment to be
greater than 90 percent solids prior to loading it into the melter,
the SITE program also evaluated a bench-scale dryer technology
as a secondary activity. The sediment for this evaluation was
dredged from the Lower Fox River, dewatered, and filter-pressed.
The PCS concentration of sediment fed into the GFT unit ranged
up to 36 parts per million (ppm) by weight.
In the GFT process, dried sediment is fed into the GFT hopper
above the feeder mechanism. The feeder conveys the sediment
continuously into the main section of the melter. At the furnace
temperature of 2,900° Fahrenheit, the sediment's organic portion
is destroyed, and the inorganic portion does not burn, but melts,
forming molten glass. The molten glass flows through the fur-
nace into the forehearth, where it is stabilized. That glass then
flows through an opening at the end of the forehearth and drops
into a water-filled quench tank. Exhaust gases flow from the
furnace through a flue. For the demonstration, air-sampling equip-
ment extracted glass-furnace emissions from this flue for labora-
tory analyses.
Minergy claims that the GFT process offers advantages over
incineration and other vitrification technologies. An incinerator
would require large quantities of fuel for treatment of low-or-
ganic-content sediments. In addition, typical waste incineration
generates large amounts of ash that require landfilling. Unlike
other vitrification technologies, GFT is designed to melt materials
that have no fuel value. Other vitrification systems typically re-
quire very high energy consumption. GFT is based on commer-
cial glass-making technology, which operates in a more energy
efficient manner. The GFT uses oxy-fuel burners, combining
natural gas and purified oxygen to create intense flames above
the glass pool.
Dried PCB-contaminated Feeder conveys the sediment
sediment placed in hopper continuously into the mam
section of the melter
Fiue
l»
Melter ma In section
Feeder mechanism
Forehearth
sourc* Mhar^owp
Waste Applicability: Minergy claims that the GFT process is
capable of treating PCB-contaminated sediment containing inor-
ganic contaminants, including mercury. Sediment contamination
is a relatively common problem throughout the Great Lakes
Basin, with sediment removal generally being the most common
remediation method. Currently, the public, particularly on a local
scale, is reluctant to accept placing PCS- and mercury-contami-
nated sediments in landfills. The public has also expressed a
desire to further explore remediation technologies that remove or
destroy contaminants whenever possible. The GFT potentially
can help address the problem of landfilling contaminated dredge
materials. Providing environmentally acceptable and cost-effec-
tive disposal of contaminated sediment would allow for more
publicly acceptable and effective cleanups.
Demonstration Approach: This technology was evaluated dur-
ing two sampling events: (1) an event associated with the opera-
tion of the bench-scale dryer, conducted January 24 to 28, 2001;
and (2) an event associated with the operation of the melter,
conducted August 14 to 17, 2001. The bench-scale dryer evalua-
tion involved sampling and analysis of the sediment prior to and
after drying, as well as sampling and analysis of effluent gas and
condensate water generated in the drying process. The melter
evaluation involved sampling and analysis of sediment prior to
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melting, glass aggregate product generated, quench water, and
furnace exhaust. System operating conditions were monitored
during both events.
The primary objectives of the SITE demonstration were:
• To determine the treatment efficiency (TE) of PCBs in
dredged-and-dewatered river sediment when processed
in the Minergy GFT.
• To determine whether the GFT glass aggregate product
meets the criteria for beneficial reuse under relevant
federal and state regulations.
In addition, the following secondary objectives were intended to
provide additional information that will be useful in evaluating the
technology.
• Determine the unit cost of operating the GFT on dredged-
and-dewatered river sediment.
• Quantify the organic and inorganic contaminant losses
resulting from the drying process.
• Characterize organic and inorganic constituents in all GFT
process input and output streams.
Demonstration Results: The preliminary results of the demon-
stration are summarized in the table. The bench-scale dryer was
evaluated by sampling and analyzing composite samples of sedi-
ment before and after the drying process. This evaluation was
designed to determine the amount, if any, of contaminants lost
during the drying process. Concentrations of mercury going into
the dryer averaged 0.92 ppm. Post-drying mercury levels aver-
aged 0.87 ppm. During the demonstration, the glass furnace
processed about 200 pounds of dried sediment per hour for 122
consecutive hours, processing a total of 25,800 pounds of dried
sediment and generating about 16,200 pounds of glass aggre-
gate product. PCS and mercury concentrations of sediment fed
into the system during the evaluation averaged 28.1 ppm and
0.72 ppm, respectively. PCS and mercury concentrations in the
glass aggregate product were below laboratory method detection
limits.
Key findings from the demonstration, including complete analyti-
cal results, operating conditions, and a cost analysis, will be
published in an Innovative Technology Evaluation Report.
Preliminary Treatment Efficiency
Calculations Table (Solids Only)
Sampling
Event
Bench-
scale
Dryer
Melter
Compound
PCBs
Mercury
PCBs
Mercury
Average Inlet
Concentration
(ppm)
1.49*
0.92
28.1
0.72
Average
TE
(%)
10.1
5.4
>99.9
>65
"Average dryer concentration based on a subset of 20 congeners.
For Further Information:
Marta K. Richards, SITE Project Manager
EPA Office of Research and Development
National Risk Management Research Laboratory
26 West Martin Luther King Drive
Cincinnati, Ohio 45268
Telephone: (513) 569-7692
FAX: (513) 569-7676
E-mail: richards.marta@epa.gov
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