Reclamation of Deep Mine Refuse Banks With Municipal Sewage Sludge

Abstract

Municipal sludge was applied on a deep mine anthracite refuse bank at rates of 80 and 108 dry Mg/ha to facilitate vegetation establishment. A monitoring system was installed to determine the effects of the sludge applications on the quality and growth of the vegetative cover, chemical properties of the soil, and chemical and bacteriological quality of the groundwater. Data collected over a 5-year period indicate that the addition of sludge improved the physical and chemical condition of the black, highly acidic refuse material and promoted establishment and continued growth of a complete vegetative cover. Sludge applications resulted in slight increases in some trace metal concentrations in the surface soil and in the vegetation. However, soil concentrations were within the normal range found in U.S. soils. Vegetation foliar trace metal concentrations were well below plant tolerance levels and no phytotoxicity symptoms were ever observed. In general, the sludge applications had no significant adverse effect on the chemical or bacteriological quality of groundwater. The results indicate that single applications of stabilized municipal sludge, applied at rates up to 108 dry Mg/ha with lime, can be used in an environmentally safe manner to revegetate coal refuse banks in the Appalachian mining region, with a cover that is self-maintaining for the 5-year period mandated under the federal Surface Mining Control and Reclamation Act of 1977.