Technology Development & Applications Group
Waste Treatment Technologies
 Brookhaven National Laboratory (BNL) has developed a low density
polyethylene encapsulation process for low-level radioactive,
hazardous, and mixed wastes that provides greater long-term
stability than products from conventional solidification
technologies. Polyethylene is an inert, low permeability,
thermoplastic material that is highly resistant to chemical attack,
microbial degradation and radiation damage.
The process uses a
modified single screw extruder to mix, heat, and extrude the
material(s) into appropriate containers where it cools and hardens
into a solid waste form which can be disposed. Alternatively, the
material can be processed using a kinetic mixer, which uses
frictional energy to melt the polymer.
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 Microencapsulation -
Polyethylene, when heated above its melting point, is combined with
dry waste to form a homogenous mixture that is allowed to cool into
a monolithic solid waste form in which small waste particles are
interspersed within the polymer matrix.
The encapsulation technology
can be applied to a variety of DOE and commercial mixed wastes,
including nitrate salts (shown in the figure to the left), sludges,
incinerator ash, ion exchange resins and sodium sulfate/boric acids.
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 Macroencapsulation - Molten polyethylene is poured into a waste
container in which large pieces of waste material have been
suspended or supported. Upon cooling the polyethylene forms a solid
layer surrounding the waste.
The Environmental Protection Agency
(EPA) has identified polymer macroencapsulation as the Best
Demonstrated Available Technology for radioactive lead solids and
mixed waste debris. The photograph on the right shows a typical
bench-scale sample of lead wool macroencapsulated in polyethylene.
 Sulfur polymer cement, developed by the U.S. Bureau of Mines in
1972, is a thermoplastic material that is easily melted to a low
viscosity liquid at 120°C. BNL has developed an encapsulation
process that can be used to soldify incinerator fly ash in sulfur
polymer cement.
The process involves using a dual-action mixer to
simultaneously heat the waste and binder with several additives to
form a homogenous mixture which simply cools into a solid monolithic
waste form without the need for chemical reactions. As much as 2.5
times more incinerator fly ash can be solidified in sulfur polymer
cement than in hydraulic cement and with improved compressive and
tensile strength properties.
Sulfur Polymer Stabilization/Solidification (SPSS) is a two stage
process developed and patented by BNL to specifically treat a broad
range of mercury wastes including elemental mercury and mercury
contaminated soil, sludge and debris. The process first reacts
the mercury to form stable mercury sulfide, with a lower vapor
pressure and solubility than untreated mercury. During the
second stage, the stabilized mercury is heated along with SPC to
form a homogeneous molten mixture that is then cooled to form a
solid matrix of encapsulated, stabilized mercury. The final
product is similar to the mineral cinnabar, which is how mercury is
found in a stable form in the environment. BNL licensed the
SPSS technology to Newmont Mining Corp. for use in treating mercury
that is generated as a result of their gold mining operations.
For more information about this technology;
More...
Thermosetting Resins
The Environmental and Waste Management Group at Brookhaven National
Laboratory (BNL) has been developing and characterizing innovative
thermosetting polymers for waste management uses for several
decades. BNL has developed and characterized thermosetting polymers
for encapsulation of hazardous, mixed, and radioactive waste, and
for container materials.
These materials cover broad ranges of
chemical and physical durability, performance, viscosity, and cost.
The polymers selected are innovative materials with desirable
properties in both their fluid, and solid states. This makes them
suitable for applications where impermeability, chemical
resistivity, high strength, and long-term durability are required.
More...
Low Temperature Glass
BNL has proposed using promising new low-temperature glasses and
glass-ceramics based on advanced phosphate formulations for the
treatment of low-level waste and mixed waste. High temperatures
(1200-1500°C) required for vitrification using borosilicate glass
are a major drawback because volatilization of certain isotopes and
heavy metals can occur. Alternative glass compositions have been
prepared with melt temperatures between 450 and 900°C and improved
durability. More...
Last Modified: June 18, 2008
Please forward all questions about this site to:
Linda Satalino
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