Application of Sewage Sludge and Other Amendments to Coal Refuse Material: I. Effects on Chemical Composition

Abstract

The effects of sewage sludge, lime, and gypsum on the chemical composition of coal refuse material were examined at a Fulton County, IL, land reclamation site. Treatments consisted of a control, 542 dry Mg ha−1 anaerobically digested sewage sludge, 89.6 Mg ha−1 lime, 112 Mg ha−1 gypsum, and combinations of these amendments. Analysis of coal refuse material (0–15 cm) from 1976 to 1981 showed that the sewage sludge + lime treatment was the most effective in maintaining the refuse pH, and in reducing water‐soluble Al and Fe, KCl extractable Al, and total acidity. Gypsum applications decreased the refuse pH and increased water‐soluble Al and Fe, KCl extractable Al, and total acidity. The effectiveness of treatments in reducing total acidity was sewage sludge + lime > gypsum + sewage sludge + lime > sewage sludge > lime > gypsum + sewage sludge > control > gypsum + lime > gypsum. Concentrations of water‐soluble Ca, Mg, and Na reflected the additions of these cations made by various treatments and the contribution of these cations to refuse electrical conductivity (EC). Profile sampling (0–100 cm) in 1976 and 1981 showed a decline in pH, and an increase in water‐soluble Al and Fe and total acidity in 1981 samples from the sewage sludge and gypsum treatments. The changes in the sludge treatment indicate there was a solubilization of metals from the refuse material and sewage sludge with time, as the surface pH (0–15 cm) declined, and a subsequent increase in the total acidity from metals and acidic by‐products leached to the 15‐ to 100‐cm depths of the coal refuse material. In the gypsum treatment, the changes observed in the 1981 profile samples reflected the leaching of H3O+, metals, and acidic by‐products of pyrite oxidation produced by exchange with Ca from the gypsum amendment.

Role of organic amendments on enhanced bioremediation of heavy metal(loid) contaminated soils

“…Biosolids have been similarly blended with lime, other alkali and various salts after biosolid production for improving alkalinity and soil productivity. Lime and gypsum treated anaerobically biosolids post production were used by Pietz et al [164,165] for revegetation of acidic coal refuse material. It was found that the lime + biosolid and gypsum + biosolid treatments reduced soil acidity and dissolved Al and increased plant productivity compared to control and individual amendments.…”

An appraisal of the potential use of fly ash for reclaiming coal mine spoil

“…The interaction of organic matter with soils is enhanced by Ca 2þ , resulting in (i) the additional pH buffering capacity of Ca 2þ present in FA, (ii) its contribution to the flocculation of soil particles and stabilization of soil structure through cation bridging and (iii) sorption of organic matter to mineral surfaces to create a more reactive environment for water, air and nutrient interactions in the soil (Palumbo et al, 2004). Sewage sludge and other mineral amendments, such as lime and gypsum, added along with FA, maintained optimum pH, altered water-soluble organic carbon and EC, and released N, P and K for assimilation by plants during re-vegetation of soil and mine spoil (Pietz et al, 1989).…”

Remediation of fly ash landfills through plantation

“…FA does not inhibit microbial activity and respiration in the case of its application of organic materials, such as swine manure (Vincini et al, 1994); in fact, an improvement in the microbial community content in degraded subsoil due to the amendment with FA has been observed (Schutter & Fuhrmann, 2001). The addition of biosolids and other amendments, including humic acid and fertilizers, to FA has been effective in maintaining the pH of the soil, improving the water-soluble OC content and electrical conductivity, and releasing N, P, and K for assimilation by plants during revegetation of soil (Martens & Beahm, 1976;Pietz et al, 1989). Although the metals content in the plant species grown was not determined in this study, it is possible that the reduction in toxicity of certain metals from FA, along with an increase in the supply of nutrients, is also likely due to the addition of organic amendments (Chu & Poon, 1999;Wong, 1995).…”