Studies on Trace Element Levels in Kiwira Coal Waste for Sustainable Utilization for Energy in Tanzania

Coal waste includes tailings, coarse rejects and coal washery disposed in piles and tailing dams. Waste coal in pile is heterogeneous in composition and variations occur horizontally and vertically. These coals pose inherent safety hazards, acid mine drainage conditions resulting in environmental impacts. Little data in physical and chemical properties is available for these wastes. In this paper environmental characterisation study was carried out to determine toxic trace elements in the coal wastes (such as As, Cd, Cr, Ni, Pb, Sb and Se) and to establish their acid generation potential to the environmental impacts at the surrounding. In order to determine the composition of the material present at any specific condition within the pile, four samples were taken from different four locations. The softer, more friable materials tend to be concentrated in the interior of the pile, while the harder, higher ash and sulphur content materials accumulate along the edges in the piles. At the centre of the pile (S3) has found to be with lower in moisture and ash content, but higher in heating value. Material at the outer edge of the pile (S1 and S4) is larger in size with higher moisture, ash contents and toxic trace element above the limit of regulatory standards.