Separation technologies/processes hazardous wastes

Because all depolymerization processes will generate waste that may be classified as hazardous waste or at least chemical waste, it will always be economically preferable to separate as much non-PET material from the PET material as is practical. Traditional bottle washing procedures can produce used bottle flake that is clean enough to be used to make more bottles or somewhat less clean and less expensive material. Technologies have been proposed to dissolve the polyester scrap in appropriate solvents to separate PET from other materials such as cotton fiber or magnetic tape components [19]. 

Following biological degradation, the extract is exposed to photochemical degradation, which removes uranium from solution as polyuranate. The metals and uranium are captured in separate treatment steps, allowing for the separation of wastes into radioactive and nonradioactive waste streams. This treatment process does not create additional hazardous wastes and allows for the reuse of the contaminated soil. The technology has been the subject of bench-scale tests and is not currently commercially available. 

In a compendium of technologies used in the treatment of hazardous waste (42) technologies are categorized into physical treatment, chemical treatment, biological processes, thermal destruction, and fixation/stabilization processes. Separation technologies are contained entirely within the physical treatment processes section. Those technologies addressed are ... 

According to the vendor, only particles from about 2 mm to 50 p,m in size can be processed by magnetic barrier separation. Some bench-scale studies suggest that high feed rates decrease separation efficiency. Materials undergoing magnetic barrier separation must then be processed by some treatment technology before the hazardous component of the waste can be disposed. 

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