Environment solid waste form

One of the more important factors affecting the isolation of radioactive waste is the rate of release of the radioactivity from the solid waste form to the environment. The most probable mechanism for release and transport of radioactivity from a solid waste form is by leaching of radioactive isotopes with groundwater. The objective of leach-testing various waste forms is to evaluate the rate at which specific hazardous radionuclides migrate from waste if and when the waste form comes in contact with groundwater. In this paper, measurement of leach rates of radioactive waste by a method which incorporates neutron activation is described. 

Our method for measuring leach rates is thought superior to other methods currently in use. Meaningful leach rate data can be obtained using relatively simple laboratory scale equipment coupled with standard NAA techniques. More detailed information can be procured by applying radiochemical separations and more sophisticated counting methods. The experimental technique described here is applicable to the measurement of leach rates for the elements of interest, from any solid waste form, in any potential storage environment. 

Solid effluents arising from metallurgical operations occur principally in two forms fine particulate solids or dusts, and solid wastes. As an example, blast furnace gas may contain up to 170 kg of dust per ton of pig iron produced. Suitable methods must be devised for processing the solid effluents for two reasons (i) to prevent pollution of the environment and (ii) to recover their valuable content, if any. As far as the latter is concerned, reference may be drawn, as an example, to the recovery of rhenium from the exit gas from molybdenite roasting in a multiple-hearth furnace. 

Allhough Ihe ceramification and SYNROC lechnologies are being researched to develop a final waste form for plutonium-contaminated materials, no experiments with plutonium have been performed. The SMITE process is designed for the treatment of solid, inorganic materials. The final waste form will leach in acidic solutions so storage in a basic environment is recommended. 

On the basis of chemical profile, Wood (38) predicted that arsenic, selenium, and tellurium will be methylated in the environment, and lead, cadmium, and zinc will not. Elemental concentration in the aquatic food chain has been reported for As (39), Hg (40), Cd (41), Pb (42), and Cu (43). The biological half-life of methylmercury in fish, for example, is one to two years (44). Pillay et al. (40) implicated heavy coal burning in the mercurial contamination of plankton and fish populations of Lake Erie. Other metals, notably cadmium, have been shown to be incorporated into the grazing grasses surrounding a coal burning source (27). Trace element contamination, therefore, can enter the food chain at various points. Disposal of solid wastes in the form of ash and slag is yet another environmental consideration (45). 

Inbar, Y., Hadar, Y., and Chen, Y. (1992). Characterization of humic substances formed during the composting of solid wastes from wineries. Sci. Total Environ. 113, 35 18. 

Actinide oxides of higher oxidation states, such as UO3 and PUO3, are rarely found in waste streams because they are formed only in a highly oxidizing environment [9]. If formed at all, they may result in oxides such as U3O8, which is a solid solution of UO2... 

Inorganic phosphate ligands are important with respect to the behavior of actinides in the environment and as potential waste forms. There have been a number of experimental studies to determine the equilibrium constants in the actinide-phosphoric acid system, but they have been complicated by the formation of relatively insoluble solid phases and the formation of ternary actinide complexes in solution. 

Of the total quantity of thallium mobilized by industry amounting to about 1600 tons in the United States during 1977, 70% was reemitted to the environment either in the form of air pollution (15%) or as solid waste (55%). Coal burning power plants account for the greater part of this air pollution, but the smelting of copper, zinc, and lead may also result in concentrated local emissions. The remaining 30% is incorporated in the final products, though usually at a lower level than in the raw materials. ... 

U.S.E.P.A. (U.S. Environmental Protection Agency), 1977. Waste Disposal practices and their effects on ground water. U.S. Environ. Prot. Agency, Off. Water Supply—off. Solid Waste Manage. Progr., Rep. to U.S. Congress, edited by D.W, Miller (Rep. also published in book form as Waste Disposal Effects on Ground Water, 1980, Premier Press, Berkeley, Calif., 512 pp.)... 

As a result of the Clean Air Act, the Water Pollution Control Act, and other federal and state laws respecting public health and the environment, greater amounts of solid waste, in the form of sludge and other pollution treatment residues, have been created. Similarly, inadequate and environmentally unsound practices for the disposal or use of solid waste have created increased amounts of air and water pollution and other problems for the environment and health. 

Polystyrene dust and powder formed during production can be a mild irritant to the eyes, skin, and respiratory system. But even for workers in the field, the risk is regarded as being very low. A more serious problem posed by the compound is the risk it poses for the environment. About half of all the polystyrene produced in the United States is used for packaging and one-time use purposes. That is, someone uses the product and then throws it away. Since polystyrene does not readily decompose, it tends to accumulate in landfills and dumps. Some environmentalists point out that large volumes of discarded polystyrene contribute significantly to the nation s solid waste disposal problems. Industry spokespersons, however, point out that polystyrene accounts for less than one percent of all solid wastes. In any case, a number of industries and companies have attempted to reduce the amount of polystyrene used in their products in order to... 

Solid waste generation represents a waste of resources and materials, which can also cause severe environmental impact on land, water and air. It is worth remembering that all pollution is a form of waste. In general, landfill, apart from representing a waste of materials, can potentially have very severe effects on the surrounding environment. These include ... 

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