Flue-Gas Desulfurization (FGD)
FGD material is derived from the “scrubbers” being installed in the smokestacks as a means to make coal burning more environmentally friendly. The scrubber process produces gypsum. This synthetic gypsum has several applications:

• Wallboard
• Road base constructing
• Cement manufacturing
• Plaster
• Soil additive

*As more plants are installing scrubbers, the amount of gypsum collected is expected to quickly rise.

Summary

Fly Ash is the most commonly used coal combustion waste. Most fly ash is used in the manufacture of Portland cement. In general, coal combustion waste is used for fill material in the construction of roadways or buildings, or as an aggregate substitute.

Attachments:
See annotated bibliography.





Truini, Joe."Study backs filling mines with coal ash."Waste News.11.24(March 13,
2006):4.General OneFile.Gale.Virginia Tech.6 Feb. 2008
A report from the National Resource Council, titled, “Managing Coal Combustion Residues in Mines,” finds that coal combustion waste, primarily coal ash, can serve as infill for old mines as part of the reclamation process. The report stresses that while this practice is generally safe, more oversight is needed to guard against the potential contamination threat. Steps need to be taken to better identity the composition of the coal ash and the Federal government is called upon to establish mine-filling guidelines.

"Editorial: Coal ash sparks bright ideas."Waste News.7.10(Sept 17, 2001):8.General OneFile.Gale.Virginia Tech.6 Feb. 2008
Article cites generic researchers from Ohio and the Dakotas who are experimenting with the use of fly ash on animal feedlots. The destructive nature of vast congregations of animals, coupled with the limited carrying capacity of the ground, leads to feeds which tend to be muddy and susceptible to massive erosion. The intent is to use the ash to harden and stabilize the soils.

Changwoo, Ann and William Mitsch. “Evaluating the use of recycled coal combustion products in constructed wetlands: an ecologic-economic modeling approach.” Ecological Modelling. 150. (2002) 117-140.
Scientists from Ohio State Universty have conducted experiments showing the benefits of using flue-gas desulfurization, a coal combustion waste, for liner material in constructed wetlands for such applications as municipal water treatment. The researchers constructed scale model wetlands and measured the results. Simulations showed increases in phosphorous retention by amounts of 10%, which translates into substantial cost savings.

"Coal ash promotes plant growth."Israel Business Today.6.n257(Dec 27,
1991):5(1).General OneFile.Gale.Virginia Tech.6 Feb. 2008
<http://find.galegroup.com.ezproxy.lib.vt.edu:8080/itx/infomark.do?&contentSet=I
ACDocuments&type=retrieve&tabID=T003&prodId=ITOF&docId=A11861043&source=gale&srcprod=ITOF&userGroupName=viva_vpi&version=1.0>.
The Hebrew University’s agriculture department has found coal ash can be added to the soil for use as a growth additive. When properly mixed with cow manure, the ash becomes a fertile soil base for plants. The findings claim 20%-30% faster growth rates. Professor Yone Chen has hopes of this method being beneficial in areas of nutrient-poor or depleted soils.

United States. Department of Energy, Office of Fossil Energy. Coal Utilization By-
Products. Topical Report Number 24. August 2006.
<http://www.netl.doe.gov/technologies/coalpower/cctc/topicalreports/pdfs/Topical2
4.pdf>
This report was commissioned by the Department of Energy and was put together by the National Energy Technology Laboratory. It provides a detailed breakdown of the major components of coal combustion waste and the specific utilization of the by-products of each group. The report highlights uses for fly ash, bottom ash, flue-gas desulfurization, and boiler slag. The report does not ignore the potential risks of using coal waste, but it mainly glosses over such concerns. It comes to the conclusion that utilization of coal waste is both an economically and environmentally beneficial.