Solute Movement from Fluidized Bed Combustion Waste in Acid Soil and Mine Spoil Columns

Abstract

AbstractFluidized bed combustion waste (FBCW), a by‐product from a specialized coal‐fired power plant, was used as a liming source to determine its impact on solute transport in the soil. The upper 10 cm of 60‐cm‐long acid silt loam soil (pH 4.6) and strip mine spoil (pH 4.1) columns was treated with enough FBCW to raise the pH of the two media to 5.0 and 6.0, and 4.6 and 6.0, respectively. Loadings of Ca, S, and Mg in the upper 10 cm of the pH 6 mine spoil treated were 1,132, 309, and 46 µg/g soil, respectively. Approximately twice these loadings were applied to the upper 10 cm of the acid soil columns. Heavy metal loading rates were very low in all treatments. Columns were leached with 10 cm of water at 10‐day intervals 7 and 14 times. Percolate samples collected from mine spoil columns treated with FBCW showed no evidence of enhanced levels of Al, B, Ca, Cd, Cr, F−, Cu, Fe, Mg, Mn, Ni, P, Pb, SO42‐, Sr, and Zn after 14 leachings. Acid soil columns, containing higher levels of organic matter, had percolate concentrations of Ca, Mg, Mn, and SO42‐ that increased with increasing FBCW liming applications. None of the analyzed constituents showed any evidence of downward migration in mine spoil matrix and only Ca moved downward into the 10‐ to 15‐cm depth of the soil matrix.