Land Application Effects of a High-Calcium, Dry Flue Gas Desulfurization By-Product on Trace Elements in Runoff from Natural Rainfall

Abstract

Due to low cost and large abundance, coal continues to be one of the major energy sources for electricity generation in the USA. The dry desulfurization of flue gases during coal combustion produces a by-product that may be potentially useful as a soil amendment. However, the influence of dry flue gas desulfurization (DFGD) by-products on trace element losses with runoff from treated fields has not been well investigated. The objective of this study was to evaluate the effects of land application of a high-Ca, DFGD by-product on trace elements lost in runoff from natural rainfall events. The by-product was applied once on May 18, 2015 at 9 Mg DFGD ha−1 to small plots of a highly weathered Ultisol under managed-grassland land use in northwest Arkansas. Runoff was collected following each runoff-producing precipitation event for 1 year. Seasonal (i.e., summer (May to August), fall (August to November), winter (November to February), and spring (February to May)) runoff, annual runoff, runoff pH, and electrical conductivity did not differ significantly between DFGD treatments. Seasonal flow-weighted mean Ni concentrations and seasonal V loads were significantly greater in runoff when amended versus the unamended control when compared during at least one 3-month season by 44.5 and 86.9% for Ni and V, respectively. Based on the results of this study, it appears that land application of a high-Ca DFGD by-product at rates ≤ 9 Mg ha−1 has minimal effects on trace elements in runoff.