Coal-Burning Byproduct Has Agricultural Use

October 4, 2005

WOOSTER, Ohio — Synthetic gypsum, a byproduct of burning coal, may have use in agriculture as a fertilizer and soil amendment, according to Ohio State University researchers.

An ongoing three-year project, led by Ohio State University soil scientist Warren Dick, has shown a 16 percent yield increase in alfalfa using synthetic gypsum as a sulfur fertilizer source. Preliminary data has shown a slight increase in corn yields when synthetic gypsum was applied at rates sufficient to supply 30 pounds per acre of sulfur.

"Coal is the No. 1 energy source in the United States and Ohio is a major coal-burning state for electricity," said Dick, a School of Natural Resources soil science professor with the Ohio Agricultural Research and Development Center. "It's important for us to find uses for products generated from burning coal that are not only cost effective but also continue to encourage environmental stewardship."

Almost 90 percent of coal burned in the United States is used to generate electricity, and coal-fired power plants produce approximately 52 percent of the nation's total electrical output. Approximately 122 million tons of coal combustion products are generated each year. Synthetic gypsum is created when coal containing sulfur is burned and the sulfur-bearing gases formed are removed by reaction with a chemical scrubber — process known as flue gas desulphurization (FGD).

Per the 1990 Clean Air Act, coal-burning industries, such as power utilities, continue to work toward reducing sulfur gas emissions, the leading cause of acid rain. Environmental control equipment to remove sulfur gases is expensive. However, manufacturing and agricultural uses exist for FGD gypsum that can help offset some of the cost, explains Dick.

Gypsum is commonly used in the production of wallboard, or sheet rock, and as a cement additive. Dick, along with other university, industry and state agency cooperators, has been researching uses for synthetic gypsum for over a decade. The mineral, like its natural counterpart, has a wide range of agricultural and horticultural benefits and was commonly used as early as the time of Benjamin Franklin who conducted several experiments with gypsum.

"Synthetic gypsum is a good source of sulfur for plants, especially for forages which require high amounts of sulfur," said Dick.

Sulfur, among other benefits, helps in chlorophyll formation, improves root growth and overall production. Gypsum is moderately soluble in water and a good source of calcium and sulfur, and it is these properties that make it a "conditioner" for building soil structure and improving water and air movement.

In addition to conducting agronomic research with forages, Dick is also exploring the potential benefits of coal combustion products in the nursery industry using fly ash, bottom ash, gypsum, or a combination of the products with compost to grow container plants.

"The goal is to see if we can take these coal-burning products and recycle them in a way that is cost-effective and beneficial to both the producer and end-user," said Dick.

The research projects are being funded through a variety of sources, including the Ohio Agricultural Research and Development Center, Ohio Coal Development Office, AgSpectrum Company, U.S. Department of Energy, FirstEnergy Corporation, Cinergy Corporation, American Electric Power Corporation, and the U.S. Department of Agriculture's Binational Agricultural Research and Development Fund (BARD).

 

Author(s): 
Candace Pollock
Source(s): 
Warren Dick