PW06 Life-Cycle Assessment
Exhibit Hall
8:00 AM - Wednesday
(PW047) A Life Cycle Assessment of Coal Combustion Products.
Lindner, Angela1, Babbitt, Callie1, 1 University of Florida, Gainesville, FL, USA
ABSTRACT- Coal-fired electric utilities in the U.S. annually generate almost 110 million metric tons of large-volume coal combustion products (CCPs), including fly ash, bottom ash, boiler slag, and flue gas desulfurization material. CCPs have chemical and physical properties that make them suitable for use in engineering and construction applications. However, these products also contain chemical constituents, mainly trace metals, that cause concern about their widespread reuse or disposal. Currently, only 28%, or 30 million metric tons, of CCPs are diverted from disposal in landfills or surface impoundments for use in applications such as concrete production, structural fill, roofing material, and gypsum wallboard. Despite potential economic and environmental savings from CCP beneficial use, there has been little attention devoted to assessing the life cycle impacts of CCP generation, disposal, and beneficial use. This study presents a life cycle assessment (LCA) of CCPs to determine environmental and human health impacts attributed to coal extraction and preparation, coal combustion, CCP disposal, and CCP beneficial use stages of the life cycle of CCPs produced in Florida. This LCA was extended to compare CCPs to traditionally used virgin raw materials in beneficial uses including concrete, structural fill, soil amendment, road construction, and gypsum wallboard, Results indicate that diverting 50% of all generated CCPs to beneficial uses results in a decrease in all emissions to air, water, and land and all raw material requirements, except limestone, coal, wood, and water. The life cycle stages of coal mining and preparation and coal combustion contributed the most significantly to impacts quantified, including ozone depletion, acidification, eutrophication, resource use, and photochemical smog formation. A comparison of beneficial uses suggests that most concern surrounds CCP use as soil amendment because of increased human health impacts; however, tradeoffs between decreased human health and ecosystem quality impacts and increased resource use were evident for all other beneficial uses.
Key words: beneficial use, coal combustion products, disposal, life cycle assessment