• Coal Ash Resources Research Consortium
• Stabilizing Feedlots Using Coal Ash
• Environmental Evaluation for Utilization of Ash in Soil Stabilization

Background
CAEEC is a cooperation among industry, government, and the research community to work together to solve CCB- related problems and promote the environmentally safe, technically sound, and economically viable utilization and disposal of CCBs.

Objectives
To improve the technical and economic aspects of coal combustion by-product (CCB) management.

Description
CARRC tasks fall into three general categories:

1. Member-prioritized research tasks,
2. Technical and administrative tasks, and
3. Special projects that support CARRC objectives and strengthen and increase the availability of sound technical data for CARRC use.

Preliminary Results

• Mercury
  For the past 17 years, CARRC has been generating and assembling important data on mercury content and release from CCBs.
• Coal Ash Properties Database
  To house results, CARRC developed the Coal Ash Properties Database (CAPD), which contains identification and characterization information on more than 800 CCB samples from throughout the world, primarily derived from member samples.
• ASTM Method Development
  Each year, CARRC remains involved in American Society for Testing and Materials (ASTM) method development, including ash leaching method development.
• Advanced Methods for CCB Characterization
  CARRC researchers developed advanced methods for CCB characterization, including x-ray diffraction and computer-controlled scanning electron microscopy (CCSEM).
• Buyer's Guide to Coal Ash-Containing Products
  Developed in 2000, the Buyer's Guide lists commercially available ash-containing products and promotes the importance of coal ash utilization.
• Topical Reports
  CARRC publishes topical reports on key issues in the ash industry.  Recent reports include:
  • Review of Handling and Use of FGD Material, 2002
  • Ammoniated Ash Annotated Bibliography, 2001
  • Feedlot Stabilization Using Coal Combustion By-Products:  An Annotated Bibliography, 2000

Status
The Coal Ash Resources Research Consortium (CARRC) will continue to work toward its primary goal to solve ash-related problems and promote the environmentally safe, economic utilization and disposal of coal combustion by-products (CCBs).  Secondary goals include the generation of scientific and engineering information regarding regulations and specifications for coal combustion fly ash, the development of improved characterization methods for coal by-products, the demonstration of new or improved coal ash use applications, and technology transfer.

Feedlots Stabilizing Using Coal Ash

"The project proves that coal ash can significantly improve animal-feeding areas, resting areas and equipment traffic areas," said Debra Pflughoeft-Hassett, manager of the Coal Ash Resources Research Consortium (CARRC) at the EERC. "Our goal was to provide farmers and ranchers with a safe, cost-effective method to improve feeding areas and pen conditions. We believe we’ve accomplished this goal."

Once this application is approved for general use, it’s estimated that more than 2 million tons of ash could be used annually in the northern Great Plains. Currently, only about 8 percent of coal ash produced each year in the northern Great Plains is utilized, leaving nearly 3 million tons to be disposed of annually.

Environmental Evaluation for Utilization of Ash in Soil Stabilization

Background
Coal combustion by-products (CCBs) are produced in large volumes at coal-fired power plants.  CCBs include fly ash, bottom ash, boiler slag, and flue gas desulfurization materials.  These materials have been shown to have advantageous properties for engineering, construction, and manufacturing applications.  CCBs, especially fly ash, have properties that are beneficial for pavement and floor slabs, reduction of shrink-swell properties of soils, and as stabilizers in aggregate road base construction and asphalt recycling.  EPRI and DOE realize that both the engineering and environmental performance of CCBs must be demonstrated and documented for CCBs to be fully accepted as a commercially viable option for soil stabilization applications.  These entities provided support for a laboratory and field investigation on the environmental performance of regionally available fly ash for soil stabilization.

Objectives
The overall goal was to evaluate the potential for release of constituents into the environment from ash used in soil stabilization projects.

Description
The Minnesota Pollution Control Agency (MPCA) approved the use of coal ash in soil stabilization, indicating that environmental data needed to be generated.  The project was designated to evaluate the environmental performance of regional coal fly ash in typical soil stabilization applications with an emphasis on addressing issues raised by the regulatory community.  To determine the types of environmental risk associated with the use of coal combustion fly ash in soil stabilization, the effort included laboratory evaluations of fly ash composition, a field demonstration to evaluate runoff quality, and laboratory leaching of stabilized soil samples from full-scale soil stabilization projects.  Xcel Energy and Mineral Solutions, Inc., chose eleven commercial sites and one field-scale demonstration site to demonstrate the environmental and engineering performance of ash in soil stabilization.  Leachate generation was performed in the laboratory using several leaching protocols, including short-and long-term batch shake-leaching procedures.  A field demonstration of soil stabilization was used to collect runoff samples generated from a simulated rainfall event.

Preliminary Results
Data were assembled from extensive laboratory and field demonstrations to prepare a comprehensive report on the environmental aspects of fly ash use in soil stabilization.

Status
Project is completed.  This study confirms the outcome of similar studies that fly ash, if used properly, is not a hazard to the environment when used for soil stabilization at the addition concentration used in the sites for this project.  Results of the runoff testing would lead one to the conclusion that stabilization with ash might be recommended method.