Hazardous or toxic waste destruction or containment – Destruction or containment of radioactive waste
Patent
1998-07-07
2000-05-09
Griffin, Steven P.
Hazardous or toxic waste destruction or containment
Destruction or containment of radioactive waste
588 2, 588 15, 588 18, 588 19, 588 20, 588205, 588227, G21F 900, G21F 928, G21F 930, G21F 932, G21F 934
Patent
active
060606355
DESCRIPTION:
BRIEF SUMMARY
This application is a 371 of international application PCT/FI97/00033 filed Jan. 23, 1997.
The present invention relates to a procedure for the treatment of hazardous waste.
Today, hazardous waste is treated in special hazardous waste disposal plants, where hazardous waste is treated in the first place by burning it in high temperatures and effectively so that the gaseous emissions produced can be admitted into the atmosphere and solid emissions can be recycled or removed to dumping places.
However, treatment of hazardous waste at high temperatures is not always an economic solution, and hazardous waste disposal pi-ants have to use fossil fuels to reach sufficiently high temperatures. Further, there are types of hazardous waste, such as radioactive waste, whose disposal by burning is out of the question because of the atmospheric emissions released via combustion.
Specifications U.S. Pat. No. 5,028,452, WO 89/10162, DE 4113440, DE 4336768 and DE 4428418 present procedures for the treatment of hazardous waste with a cold plasma formed by oxygen.
Prior-art methods for waste treatment are generally not applicable for the treatment of radioactive hazardous waste. In the treatment of radioactive hazardous waste, it is important that no emissions should be admitted into the atmosphere or waste water. In some way or another, all radioactive waste has to be finally so stored that no emissions are released into the environment. At present, e.g. in connection with the treatment of the waste water of nuclear power stations using ion-exchange resin, low-activity waste is generated which cannot be burned as such expressly because of the radioactive emissions released during combustion. For final storage of the radioactive waste contained in the resin, the resin has been subjected to a bacterial treatment and the bacterial mass obtained has been mixed in concrete mass for final storage. However, there are difficulties and problems in bacterial treatment of resin and final storage of the mass obtained.
The object of the present invention is to produce a new method for treating radioactive hazardous waste in such a way that hazardous waste can also be treated in lower temperatures and without releasing harmful emissions into the atmosphere.
As for the features characteristic of the invention, reference is made to the claims.
The invention is based on the basic idea, developed in the investigations which have been carried out, of converting oxygen into the form of a cold plasma and feeding the oxygen and waste together. Since oxygen in the form of a cold plasma is very reactive, hazardous waste can easily be oxidized into a harmless form using such oxygen plasma.
Oxygen can be converted into the form of a cold plasma by subjecting it to radio-frequency electromagnetic radiation, preferably with a frequency of 2-14 MHz. If desirable, hazardous waste can also be treated with such electromagnetic radiation.
The treatment of waste with oxygen in the form of a plasma is preferably carried out at a temperature of 60-150.degree. C. If desired, it Is also possible to use temperatures lower or higher than this.
The treatment of hazardous waste with oxygen in the form of a plasma can be carried out in a desired pressure, a negative or a positive pressure. In a preferred embodiment of the invention, the treatment is performed in negative pressure conditions.
The invention is also applicable for the treatment of radioactive waste, e.g. low-activity waste. Low-activity waste is produced e.g. in treatment of the cooling water of nuclear power stations with ion-exchange resin, which is used to remove radioactive substances from the waste water, i.e. to bind them with the resin. Low-activity ion-exchange resin cannon be burned as such because of the radioactive emissions released during combustion. Therefore, the main approach regarding the treatment of such resin has been to place it in final storage. For this purpose, the resin has been fed to bacteria and the bacterial mass obtained has been mixed in concrete mass or final storage. How
REFERENCES:
patent: 3948601 (1976-04-01), Fraser et al.
patent: 4909164 (1990-03-01), Shohet et al.
patent: 5028452 (1991-07-01), Beatty
patent: 5134946 (1992-08-01), Poovey
patent: 5545803 (1996-08-01), Heath et al.
patent: 5882581 (1995-11-01), Gotovchiikov et al.
Taylor, Overview of Thermal Plasma Technology, "Proc. Conf. Electron Beam Melting Refin.", pp. 40-54, 1996.
Peters et al., Treatment Alternatives for Greater-Than-Class C Low Level Waste, 8p, 1990.
Griffin Steven P.
Nave Eileen E.
Valtion teknillinen tutkimuskeskus
LandOfFree
Method for treating hazardous waste does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for treating hazardous waste, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for treating hazardous waste will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1066671