#98-25

Contact: Kara Villamil, or Mona S. Rowe

Released March 25, 1998

 

 

BNL TECHNIQUE LICENSED TO SEAL RADIOACTIVE WASTE

Process Will Help in Cleanup of Contaminated Sites Across U.S.

UPTON, NY - An environmental company has begun packaging radioactive and hazardous industrial waste for safe disposal using a new method developed and patented by the U.S. Department of Energy's Brookhaven National Laboratory.

Envirocare of Utah, which treats and disposes of low level radioactive and mixed wastes, has licensed the BNL technique for full-scale commercial use.

The company's Clive, Utah location processes and disposes of waste generated by industry and government agencies, and by cleanup efforts at contaminated sites around the country. It is the only commercial facility in the U.S. approved by the Nuclear Regulatory Commission for the disposal of mixed waste, which contains both toxic and radioactive components.

"This transfer of technology from the Lab to the private sector means that polluted sites around the country will be cleaned up faster," said BNL's Paul Kalb, a co-inventor of the process.

The approach, called polymer microencapsulation, reduces leaching (leaking) of contaminants into the environment to very low levels from waste that is being stored or disposed of in a landfill. It can be used on virtually any waste, including incinerator ash, sludges and concentrated liquid waste.

The process first converts waste into a powder by drying or shredding it. Then, the waste powder is poured into a machine called an extruder, where it is mixed with a hot, melted form of a non-biodegradable plastic known as polyethylene. Inexpensive and plentiful, polyethylene is also commonly used in shopping bags and milk jugs. Extruders are used widely in the plastic industry.

While the waste and plastic are mixing, a third ingredient may be added to bind up radioactive elements and toxic chemicals in the waste. Then, the mixture is fed into a lined 55-gallon drum, where it cools to form a solid, monolithic waste form. After the polyethylene has cooled and hardened, the waste particles are completely surrounded by plastic.

"Our process can be used on wastes that have been difficult to handle in the past, including mixed wastes that are difficult to treat using conventional methods," said Kalb. "No chemical reaction is needed to seal the waste in the plastic, just cooling and hardening, and the plastic protects the waste from chemical reactions with air, water and environmental conditions that can lead to migration of contaminants."

Other materials already used to contain mixed waste, such as concrete, require a chemical reaction to harden and may interact with the waste, reducing product quality, performance, and durability.

That durability is important to ensure that waste drums in underground areas can withstand the worst possible conditions, such as earthquakes, precipitation, erosion and floods, that might occur over the next 1,000 years.

BNL patented the technique in July 1997, after several years of development in the Lab's Environmental & Waste Technology Center, located in the Department of Advanced Technology and funded by DOE's Office of Environmental Management. Envirocare's non-exclusive license on the patent was signed in December 1997.

Previously, Envirocare, with technical assistance from Brookhaven, commercialized another BNL process called macroencapsulation, which envelopes larger waste particles and pieces in polyethylene using an extruder. That technology was successfully demonstrated in 1996 on 500,000 pounds of lead waste from DOE sites, including 20,000 pounds from Brookhaven.

Brookhaven National Laboratory carries out basic and applied research in the physical, biomedical and environmental sciences and in selected energy technologies. Brookhaven is operated by Brookhaven Science Associates, a nonprofit research management organization, under contract with the U.S. Department of Energy.

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