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Surface coal mine land reclamation using a dry flue gas desulfurization product: Short-term and long-term water responses

Chen, Liming, Stehouwer, Richard, Tong, Xiaogang, Kost, Dave, Bigham, Jerry M., Dick, Warren A.
Chemosphere 2015 v.134 pp. 459-465
acid mine drainage, arsenic, barium, calcium, chromium, coal, composts, environmental impact, field experimentation, flue gas desulfurization, land restoration, limestone, mercury, mined soils, pH, planting, runoff, sward, water flow, yard wastes, United States
Abandoned coal-mined lands are a worldwide concern due to their potential negative environmental impacts, including erosion and development of acid mine drainage. A field study investigated the use of a dry flue gas desulfurization product for reclamation of abandoned coal mined land in USA. Treatments included flue gas desulfurization product at a rate of 280Mgha−1 (FGD), FGD at the same rate plus 112Mgha−1 yard waste compost (FGD/C), and conventional reclamation that included 20cm of re-soil material plus 157Mgha−1 of agricultural limestone (SOIL). A grass-legume sward was planted after treatment applications. Chemical properties of surface runoff and tile water (collected from a depth of 1.2m below the ground surface) were measured over both short-term (1–4yr) and long-term (14–20yr) periods following reclamation. The pH of surface runoff water was increased from approximately 3, and then sustained at 7 or higher by all treatments for up to 20yr, and the pH of tile flow water was also increased and sustained above 5 for 20yr. Compared with SOIL, concentrations of Ca, S and B in surface runoff and tile flow water were generally increased by the treatments with FGD product in both short- and long-term measurements and concentrations of the trace elements were generally not statistically increased in surface runoff and tile flow water over the 20-yr period. However, concentrations of As, Ba, Cr and Hg were occasionally elevated. These results suggest the use of FGD product for remediating acidic surface coal mined sites can provide effective, long-term reclamation.