Chemical Composition of Leachate of Dairy Manure Mixed with Fluidized Bed Combustion Residue
1999
Elrashidi, M. A. | Baligar, V. C. | Korcak, R. F. | Persaud, N. | Ritchey, K. D.
This study was initiated to investigate the hypothesis that using Fiuidized Bed Combustion (FBC) residue to stabilize a dairy feedlot surface (DFS) could enhance element attenuation and minimize the environmental impact on water quality. The laboratory leaching experiment included FBC, dairy manure (DM), and DM/FBC treatments. The leaching process consisted of 10 weekly additions of distilled water, each of 460 mL. Using FBC with DM decreased the concentration of most elements (e.g., P, N, K, Ca, Al, Si, Fe, Mn, Cu, Zn, Pb, Cd, Co, Cr, Ni, As, and Se) in the leachate. A decrease ranging from 5.6 to 100% was obtained. The presence of high concentration of dissolved organic matter (DOM) is believed to enhance element attenuation by FBC minerals (e.g., Feo, and Al-oxides). Several mechanisms involved in this process are proposed: (i) formation of insoluble metal-organic complexes; (ii) sorption of soluble organic and inorganic species on mineral surfaces; and (iii) precipitation of soluble inorganic species. These mechanisms are discussed in relation to each of the measured elements. On the other hand, using FBC with DM appeared to increase the concentration of B (235%), S (47.3%), and Mg (36.5%) in the leachate. Reactions of DOM with FBC minerals to form soluble organic complexes were suggested to explain B and S increases. The increase in leached Mg could be attributed to the presence of SO²⁻₄. Our results provide evidence that using FBC to stabilize DFS has the advantage of immobilizing a large portion of most elements present in DM leachate.
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