Papers by Author: M. Katzschner

Abstract: An enhanced entry of heavy metals and metalloids into ground and surface water was observed in the historical hard coal mining areas of the districts of Zwickau and Lugau/ Oelsnitz in Saxonia, Germany. Heavy metals and metalloids like Mn, Co, Ni, Zn, As and Cd are enriched in the surface waters of the district. This environmental impact is observed even though a recultivation of some of the dumps occurred partially already 50 years ago. In this study, preliminary microbial and geochemical characterizations of samples from drilling cores in different depths of a dump site, of surface and ground water samples, and of sediments are described. Thiobacillus denitrificans appeared to be a dominating species in these moderately acidic environment especially where there is nitrate infiltration and inflow, respectively, due to agricultural use of the adjacent area. Some of the sediment samples also contained high counts of iron- and sulfate-reducing bacteria due to the organic detritus on the sediment surface.

Abstract: Electrical and electronic equipment (EEE), e.g. printed circuit boards, contain substantial amounts of metals, e.g. Cu, Pb and Sn. The objective of this work was to investigate the bioleaching of a material, originating from a technical waste processing facility, as one possible way of a complete separation of the metals from the polymer carrier. During the leaching experiments the mechanism of the leaching process was investigated, and biofilms and precipitates were analyzed by microscopical (SEM) and spectroscopical methods (EDX, XRF, XRD). The enhanced formation of exopolymer layers seems to promote the precipitation of secondary mineral particles beneath and the sorption of particles from the suspension on the layer surface.