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Impact of Leaching Conditions on Constituents Release from Flue Gas Desulfurization Gypsum (FGDG) and FGDG-Soil Mixture
Citation:
Koralegedara, N., S. Al-Abed, M. Arambewela, AND D. Dionysiou. Impact of Leaching Conditions on Constituents Release from Flue Gas Desulfurization Gypsum (FGDG) and FGDG-Soil Mixture. JOURNAL OF HAZARDOUS MATERIALS. Elsevier Science Ltd, New York, NY, 324(PART A):83-93, (2017). https://doi.org/10.1016/j.jhazmat.2016.01.019
Impact/Purpose:
Flue Gas Desulfurization Gypsum (FGDG) has been used for many beneficial purposes. However, the leaching of heavy metals from FGDG into the environment is of great concern. Even though a number of studies have been performed regarding the application of FGDG containing products for agricultural purposes, only few studies considered heavy metal leaching from the FGDG to soil and ground water sources. The main objective of this work was to study heavy metal leaching from FGDG that can potentially be used as a soil amendment under different management scenarios. This is the first study that used newly approved EPA leaching methods to assess metal leaching from FGDG and amended soils, and provides many details about metal leaching under different environmental conditions and at a high application rate, which addresses the worst case scenario. Even though FGDG used in this study contained many toxic heavy metals, only Se, B, Ba, Mn, Mo, Sr and Zn were released under all the tested environmental conditions. The data from this study will be useful to the FGDG industry, agriculture, and government agencies to determine the proper approach for using FGDG as a soil amendment.
Description:
The interest in using Flue Gas Desulfurization Gypsum(FGDG) has increased recently. This study evaluates the leaching characteristics of trace elements in "modern" FGDG (produced after fly ash removal) and FGDG-mixed soil (SF) under different environmental conditions using recently approved EPA leaching methods (1313-1316). These methods employ various pH and liquid-solid (LS) ratios under a batch leaching, column percolation and diffusion controlled release scenarios. Toxicity Characteristic Leaching Protocol (TCLP) and Synthetic Precipitation Leaching Protocol (SPLP) were used for comparison. The data obtained from new EPA methods provide broad insight into constituent release from FGDG and SF when compared to TCLP and SPLP. The release of toxic elements such as Hg, As, Pb, Co, Cd and Cr from SF was negligible. High release of B from FGDG was observed under all tested conditions; however, its release from SF was low. Both FGDG and SF released se under all pH conditions (2-13) and LS ratios (1-10) in low concentrations (0.02-0.2 mg/L). The data from this study could be used to investigate potential use of "modern" FGDG for new beneficial land applications.
URLs/Downloads:
DOI: Impact of Leaching Conditions on Constituents Release from Flue Gas Desulfurization Gypsum (FGDG) and FGDG-Soil Mixture
http://dx.doi.org/10.1016/j.jhazmat.2016.01.019
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