ATG Inc. Awarded U.S. Patent for Innovative Waste Vitrification System
ATG Inc., a leading provider of low-level radioactive waste treatment services, has been awarded a waste treatment technology patent by the United States Patent Office for its new waste vitrification system. ATG received U.S. Patent Number 5,809,91for the invention, which is called the Multi-Zone Waste Processing Reactor System. ATG is a radioactive and hazardous waste management company that offers comprehensive thermal and non-thermal treatment solutions for low-level radioactive waste and low-level mixed waste. Typically, the waste products treated by ATG are generated by the DoD, the DOE, and commercial entities like nuclear power plants. However, ATG also handles waste from medical facilities and research institutions, both in the United States and overseas.
The new system is a multi-zone reactor system based on employing plasma or joule effect heaters to destroy organic matter and glassify the inorganic constituents. Glass is the most stable form for the safe disposal. The system employs the new technology for the treatment of heterogeneous solid wastes, such as hazardous and radioactive solid and liquid wastes. In addition, the new technology can be used to treat municipal garbage and municipal sewage.
What makes this system different from other systems is that this is not an incinerator. Rather, it is a high-temperature thermal device that makes glass. Depending on the materials being cleaned-up, this system can reduce the volume of the material by as much as 200 to 1. Further, the mass of the tainted materials can be reduced by as much as 10 to 1, 25 to 1, or even 50 to 1, depending ion the type of material.
According to ATG Waste Management Services president Bill Hewitt, "our utility customers describe it as a robust system that meets their particular needs. Overall it's a really environmentally friendly system. The effluents that come out are extremely clean and the glass that comes out the best form of waste to handle."
The system has been developed to allow a great deal of flexibility to the users. Depending on what the customers needs might be, the system can adapt to those particular needs. This is due largely to the fact that there are three basic components to the system.
The first component and central part of the system is the glass melter, which went online in September of 1997. The second component, which went online in August, is the bulk-processing unit. The third component is called Gas Vitrification unit or GASVIT. A unique property of this system is that the waste gasses all come together and are treated through the same train. This type of processing classifies some of the materials from the gas waste.
In the first part of the SAFGLAS system, waste enters the glassmelter and is destroyed and the gases go into the quencher. The quenching agent in the quencher is high-purity water. The 35-micron droplets come out of the second zone melter at 2,000ºF and hit the quencher. This drops the temperature to about 500ºF in a fraction of a second. The importance of this rapid temperature drop is that it the waste gets quenched so quickly that no dioxins form. The waste then goes from the quenching tower to the baghouse for micron-level filtration. Finally the waste gas goes through two sets of high-efficiency particulate attenuation (HEPA) filters in series. Each set of HEPA filters removes 99.97% of the particles which are 0.3 microns or larger. In addition, before exiting the system, the waste gasses go through carbon filters, a series of monitors, and are then released. By the time the system is through with the waste gases, the gases are cleaned up by a factor of about a million. Since the system treats low-level waste, this is a highly effective system.
The bulk processing unit of ATG's SAFGLAS system, the second part of the system, is unique in that this bulk processor cooks the waste in its own containers. This reduces the volume of the waste and the remainder can then be returned to the company contracting or be disposed of. This design offers two benefits to users. The first benefit is that this system permits the waste to be mitigated without letting it get, mixed with any other waste. This makes the result easier to catalog and control. In addition, many companies are very nervous about the prospect of their waste getting mixed with waste from other companies. Safety, reporting, and liability issues of mixed waste make the no-mix concept very attractive to SAFGLAS users. The other advantage is the elimination of presorting. Typically, when waste comes into a facility there is a large amount of person-power involved in the presorting of materials. Because the bulk processor cooks the waste in its own containers this whole step in the process is eliminated, saving time and money. Finally, all of the gasses from the bulk-processing unit go right into the melter.
The third and final component of the system, the GASVIT uses both plasma and joule heating systems. Joule heating involves the use of electrodes in molten glass, which does conduct some current and creates heat. The GASVIT starts with a plasma torch in the gas section of the unit and then goes to the joule heating in the glass below. In addition, both of these heating systems are housed in the same container.
A significant advantage of the ATG GASVIT is that unlike other systems it can handle metals. At the end of the cycle, metals introduced into the GASVIT are just emptied out with all of the other materials. In addition, the GASVIT has been designed to handle highly-corrosive materials such as PVC, which becomes hydrochloric acid when melted and Teflon, which becomes hydrofluoric acid when melted.
At the terminal point of the GASVIT there is a small scrubber that removes corrosive gasses. This also creates a benefit. While similar waste mitigation units need to have the entire unit scrubbed, this system requires only that the GASVIT unit be scrubbed. This substantially mitigates the volume of secondary waste created in the processing.
The technology incorporated into the company's SAFGLAS thermal treatment system located at ATG's Richland, Washington operating facility has been operating successfully in the treatment low-level radioactive waste since October of last year.
"This patent reinforces our lead over the competition in providing new technologies for the safe and economical treatment of radioactive waste," says Doreen Chiu, CEO of ATG Inc. "The patent fortifies our SAFGLAS vitrification technology and may create domestic and international royalty opportunities. SAFGLAS is one of the nation's only commercially proven vitrification processes for treating radioactive waste, " adds Ms. Chiu.
For more information contact ATG Inc. 510-490-3008