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From Power Plant to Peanut Production

September 06, 2017   By Susan Jackson in Environmental Stewardship

Gypsum produced at a Santee Cooper generating station is applied to peanut plants at a farm in Orangeburg County.

Synthetic gypsum is formed when fossil-fueled power plants use their flue-gas desulfurization (FGD) systems to remove sulfur dioxide from the stack gases.

Using a process referred to as “scrubbing,” stack gases are fed through calcium carbonate (i.e. limestone) to eliminate impurities and environmental concerns. When the sulfur dioxide is removed, synthetic gypsum is formed.

The majority of the synthetic gypsum at Santee Cooper’s Cross Generating Station was dewatered and trucked to a wallboard facility where it is used to make drywall. However, some of the synthetic gypsum wasn’t able to be dewatered so it had been sent to a lined wastewater pond.

In 2016, Santee Cooper began excavating this quality gypsum from the pond and stacking it in large stockpiles. After allowing it to dry naturally and extensive testing, it was decided that this gypsum could be used for agriculture. After receiving approval from the S.C. Department of Environmental Control and a license from Clemson University, Santee Cooper began marketing this gypsum to Cameron Agriculture in Orangeburg County where it was used for agriculture. 

Because natural gypsum and synthetic FGD gypsum have the same chemical composition, having an available supply of “local” gypsum is very good for South Carolina farmers. Without a local supply, the gypsum would have to be transported into the state which increases traffic, carbon-dioxide emissions, and possibly the cost of the gypsum. 

From April 2016 through June 2017, Cameron Agriculture helped Santee Cooper recycle more than 150,000 tons of synthetic gypsum from Cross Station. Much of this was used by the agricultural community to increase crop yields, and specifically for peanut production is South Carolina.   

Gypsum provides an excellent source of calcium and sulfur for plant nutrition and improves crop yields. When gypsum is applied to soil, it allows water to move into the soil which increases the water-use efficiency of crops. It also helps reduce runoff and erosion because gypsum helps keep the phosphorus and other nutrients from leaving farm fields.   

One of the best parts of this recycling effort was the direct improvement to South Carolina farmland. However the very best part was…the peanuts!