Process for the treatment of mixed wastes
AssigneeChemical Waste Management, Inc.
InventorsGreg Gilles, Matt Husain
Life of this patent
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Abstract
A process is presented for treating and detoxifying mixed wastes, especially those containing volatile chemically oxidizable organics, nonvolatile inorganics and radioactive pollutants. The process combines an efficient extraction system, a filtration step, and evaporation system to concentrate the pollutants originally present in the mixed waste and a catalytic oxidation reaction to convert the volatilized organic and inorganic pollutants. A condensate product is obtained that is recycled internally to provide a closed system that discharges only inert gases and treated solid products.
Claims16
A process comprising:
- continuously treating mixed waste containing solids contaminated with radionuclides, volatile chemically oxidizable pollutants, and nonvolatile pollutants comprising toxic metals, in combination, the steps of:
- (a) mixing the mixed waste and an extractant solution at conditions sufficient to effect the mass transfer of at least a porion of the radionuclides, volatile chemically oxidizable pollutants, and nonvolatile pollutants from the solids present in the mixed waste to the extraction solution;
- (b) removing the solids from the mixture of step (a) initially present in the mixed waste;
- (c) mixing the solids from step (b) with a treated water stream;
- (d) filtering and pressing the mixture from step (c) to form a filter cake and a dilute contaminant liquid stream;
- (e) recycling the dilute contaminant liquid stream to the mixture of step (a);
- (f) removing a contaminated liquid stream comprising the radionuclides, volatile chemically oxidizable pollutants, and nonvolatile pollutants from the mixture of step (a);
- (g) continuously concentrating the radionuclides and nonvolatile pollutants in the contaminated liquid stream by continuous evaporation that simultaneously produces a first stream comprising the concentrated radionuclides and nonvolatile pollutants and a second water rich vapor phase stream substantially free of minerals, dissolved solids and metals, and comprising the volatile chemically oxidizable pollutants originally present in the contaminated liquid stream;
- (h) removing the first stream comprising concentrated radionuclides and nonvolatile pollutants;
- (i) contacting substantially all of the second stream with a solid oxidation catalyst in the presence of steam at gas phase oxidation conditions to convert the volatile chemically oxidizable pollutants, thereby producing a gaseous reaction product comprising steam and incondensible gases, the solid oxidation catalyst comprising an inorganic oxide support containing at least one metal oxide;
- (j) condensing and scrubbing the steam from step (i) to produce the treated water stream;
- and,
- (k) recycling the treated water from step (j) for mixing with the solids from step (b) and with the mixed waste and extraction solution of Step (2).
Dependencies are inferred from the claim text.