Disposal technologies

Landfill methods are considered the most economical and environmentally acceptable way of disposing of solid wastes throughout the world. Even with the implementation of waste reduction, recycling, and transformation technologies, disposal of residual solid waste in landfill will still remain an important component of an integrated solid waste management strategy.4... 

Production Technology. Processes for extraction of P2O3 from phosphate rock by sulfuric acid vary widely, but all produce a phosphoric acid—calcium sulfate slurry that requires soHds-Hquid separation (usually by filtration (qv)), countercurrent washing of the soHds to improve P2O3 recovery, and concentration of the acid. Volatilized fluorine compounds are scmbbed and calcium sulfate is disposed of in a variety of ways. 

Haemonetics Bowl Technology. Haemonetics disposable bowl technology has evolved from the original plasma separation chamber. The two principal shapes of bowls are the Latham bowl and the blow-molded bowl (Fig. 4). 

California and Minnesota have placed restrictions on the disposal of fluorescent light tubes, which contain from 40—50 mg of mercury per tube, depending on size. After batteries, fluorescent lamps are the second largest contributor of mercury in soHd waste streams in the United States (3,14). A California law classifies the disposal of 25 or more fluorescent lamp tubes as hazardous waste. In Minnesota, all waste lamps generated from commercial sources are considered hazardous waste. Private homes are, however, exempt from the law (14). Other states have proposed similar regulations. Several companies have developed technologies for recovering mercury from spent lamps (14). 

Other wastes are expected to arise from the decontarnination and decommissioning of existing nuclear faciHties. These include reactors at the time of life extension or at the end of their operating life. Whereas technologies are available for waste disposal, as of this writing (ca 1995) there is much pubHc resistance to the estabHshment of disposal faciHties. 

Fig. 4. Integrated vault technology for low level waste disposal where A represents waste containers that are placed in concrete overpacks and sealed with grout B, closed modules covered with a multiple-layer earthen cover, to direct water away from modules, and short rooted vegetation for erosion control and C, overpacks placed in reinforced concrete modules which are closed with a reinforced concrete roof Courtesy of Chem-Nuclear Systems, Inc.

Future technology developments in paraffin alkylation will be greatly influenced by environmental considerations. The demand for alkylate product will continue to increase because alkylate is one of the most desirable components in modern low emission gasoline formulations. Increased attention will be focused on improving process safety, reducing waste disposal requirements, and limiting the environmental consequences of any process emissions. 

Concerns over safe handling of radioactive materials and issues around the cost and disposal of low level radioactive waste has stimulated the development of nonradiometric products and technologies with the aim of replacing radioactive tracers in research and medical diagnosis (25). However, for many of the appHcations described, radioactive tracer technology is expected to continue to be widely used because of its sensitivity and specificity when compared with colorimetric, fluorescent, or chemiluminescent detection methods. 

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