Disposal coal combustion wastes

The level of natural versus man-made emissions to the environment are of a similar magnitude. SoH erosion is the major contributor of natural emissions with zinc mining, zinc production facHities, iron and steel production, corrosion of galvanized stmctures, coal and fuel combustion, waste disposal and incineration, and the use of zinc fertilizers and pesticides being the principal anthropogenic contributors. 

Donahoe, R. J. (2004). Secondary Mineral Formation in Coal Combustion Byproduct Disposal Facilities Implications for Trace Element Sequestration. In Giere, R. Stille, P. (eds) Energy, Waste, and the Environment a Geochemical Perspective. Geological Society, London, Special Publications, 236, 641-658. 

Coal combustion wastes characterization, reuse and disposal... 

Coal will continue in the foreseeable future as a major source of energy, and thus coal combustion waste will continue to be generated. However, problems associated with near-surface and shallow disposal of combustion products have already arisen and, as the geochemical footprint of disposal sites continues to spread, affecting surface and groundwater quality, disposal practices are likely to increasingly attract critical attention. 

The description of the workings of the control technologies is beyond the scope of this article. However, it is worth noting that many of these technologies create substantial amounts of solid or liquid waste that needs to be disposed of properly. For example, in the USA the total amount of fly ash produced from coal combustion alone is about 57 Mt/y (Kalyoncu 2000). About one-third is utilized as secondary raw material (e.g., for aggregate and asphalt), but the rest is usually disposed of in landfills. The wet and dry scrubbers for S02 control produce a sludge or dry waste that finds little secondary use, and a large amount is disposed in landfills. 

The disposal of coal combustion residues must take into account the nature and amount of the products to be disposed, as well as the nature of the disposal environment. It is a characteristic of coal utilization that many historic wastes exist that lack, or almost totally lack, characterization data. Only in recent decades, with concern over the environmental impacts of present and future accumulation of wastes, have characterization studies been made. The principal types of waste are described in Table 5. 

Rai, D., Mattigod, S. V., Eary, L. E. Ainsworth, C. C. 1988. Fundamental approach for prediction pore-water composition in fossil fuel combustion wastes. In McCarthy, G. J., Glassf.r, F. P., Roy, D. M. Hemmings, R. T. (eds) Fly Ash and Coal Conversion Byproducts Characterization, Utilization and Disposal (Symposium Proceedings VI13). Materials Research Society, Pittsburg, PA, 317-324. 

A positive result of TDF use in waste wood boilers is that facilities are able to bum sludge and waste wood more successfully, decreasing the likelihood of solid waste disposal problems. Results from a series of waste wood boiler performance tests using ASMS codes concluded that use of TDF supplementally in hog-fuel boilers enhances combustion of wood waste, and enables disposal of biological sludge in conjunction with wood waste without necessitating use of other fossil fuels such as coal.2 No applicable environmental limits were exceeded during these tests.2... 

Acenaphthene is a component of crude oil and a product of combustion, which may be produced and released to the environment during natural fires. Emissions from petroleum refining, coal tar distillation, coal combustion, and diesel fueled engines are the major contributors of acenaphthene to the environment. Acenaphthene is used as a chemical intermediate and may be released to the environment via manufacturing effluents and the disposal of manufacturing waste by-products. Because of the widespread use of acenaphthene in a variety of products, acenaphthene may also be released to the environment through landfills, municipal waste... 

Estimates for usage of coal in the U.S.A. for the year 1980 range up to S-IO metric tons (t) (Surprenant et at, 1975). Waste products from coal combustion include fly ash and bottom ash. Projected production of these ashes in 1980 is estimated at 75 10 t (Faber et al., 1976). Disposal of the ash material is one of the major environmental problems associated with the use of coal-fired power plants. 

Many of the elements that cause concern are trapped within the fly ash after coal combustion and sometimes in the bottom ash by-products. Coal beneficiation processes prior to utilization may serve as a means of reducing the levels of at least some trace elements. Elements of concern that occur at significant levels in the processing residues may give rise to waste disposal or control problems such as leaching into the natural environment via ground or surface water infiltration. 

Another issue related to waste disposal arose because of the oxidation of pyrite that produces acidic compounds, which, with other toxic materials, can be leached into the local water supply. Simultaneously, heat produced from such chemical reactions led to spontaneous combustion of coal particles in the waste tips (Guney, 1968 McNay, 1971). The potential hazards from spontaneous combustion in the spoil heaps can be substantially reduced by controlled tipping, site selection, as well as compaction of waste. 

FOODS AND FUELS (SECTION 5.8) The fuel value of a substance is the heat released when one gram of the substance is combusted. Different types of foods have different fuel values and differing abilities to be stored in the body. The most common fuels are hydrocarbons that are found as fossil fuels, such as natural gas, petroleum, and coal. Renewable energy sources include solar energy, wind energy, biomass, and hydroelectric energy. Nuclear power does not utilize fossil fuels but does create controversial waste-disposal problems. 

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