Leachability of trace elements in coal and coal combustion wastes

Leaching of trace elements from coal and coal combustion waste (CCW) products from a coal-fired power plant, burning coal from the Appalachian and Illinois basins, was studied using deionized (DI) water as a lixiviant to resemble natural conditions in waste disposal sites exposed to dilute meteoric water infiltration. Samples of bottom ash, fly ash, and feed coal were collected from two combustion units at monthly intervals, along with a bulk sample of wastes deposited in an on-site disposal pond. The units burn different coals, one a high-sulfur coal (2.65 to 3.5 weight percent S) and the other, a low-sulfur coal (0.6--0.9 eight percent S). Short-term batch leaches with DI water were performed for times varying from a few minutes to 18 hours. Select fly ash samples were also placed in long-term (> 1 year) flow-through columns.