The volume of flue gas desulfurization (FGD) by-products is expected to increase as a result of continued stringent federal and state regulations requiring significant reductions in sulfur oxide and other pollutants. Simultaneously, the agricultural profile of Illinois is changing to meet the demand for more ethanol. Changes in fertilization methods and crop rotation, coupled with environmental requirements to upgrade to clean-burning coal systems, could link the agricultural and power-generation markets in the state of Illinois in the form of FGD by-products utilized as fertilizer additives. Previous studies have shown that treating manure with coal combustion by-products, such as those from FGD, can provide beneficial results in stabilizing manure phosphorus and increasing yields. Many studies have, however, not focused on the mineralogical and chemical composition of FGD by-products when mixed with manure and the possible environmental impacts from the leaching of potential groundwater contaminants. The main objective of this project was to characterize and compare samples from three separate coal-fired power plants in Illinois to investigate the mineralogical and chemical composition of different ratios of FGD by-products to swine manure. The mineralogical properties of the FGD samples were determined by X-ray diffraction methods. Chemical composition was determined by inductively coupled plasma spectroscopy-mass spectroscopy and whole-rock X-ray florescence after the FGD by-product–manure mixtures were subjected to a Standard Test Method for Shake Extraction of Solid Waste with Water. When the samples were exposed to water, bassanite was converted to gypsum. Chemical analysis demonstrated that the ratio of FGD by-products to manure could determine the concentrations of soil nutrients such as phosphate or calcium that would have a direct impact on crop variables such as root growth, crop yield, crop health, or growth rates. The concentrations of aluminum, cadmium, cobalt, chromium, molybdenum, nickel, lead, antimony, and zinc in the 18-hour and 26-day laboratory extracts were at or less than the analytical detection limits. Arsenic was not detected in any of the extracts. Selenium was present, but in trace amounts near the analytical detection limits. The reaction pH values of the sample mixtures suggested that potential groundwater contaminants would be relatively insoluble. Considering the chemical and mineral characteristics of the FGD by-product–manure mixtures, however, it is still difficult to accurately predict environmental interactions in an open system. Additional work is needed before FGD by-product–manure mixes can be applied in commercial agricultural practices.
|Original language||English (US)|
|Title of host publication||Proceedings of the 47th forum on the Geology of industrial minerals|
|Publisher||Illinois State Geological Survey, Prairie Research Institute|
|State||Published - 2015|