Microbial leaching in environmental clean-up programmes

Microbial leaching is a simple and effective technology for extracting valuable metals from low-grade ores and mineral concentrates. Besides the industrial application for raw materials supply, microbial leaching has some potential for remediation of mining sites, treatment of mineral industrial waste products, detoxification of sewage sludge and for remediation of soils and sediments contaminated with heavy metals. There is no routine treatment for toxic metals dispersed in solid materials, and autotrophic and heterotrophic leaching processes may be considered for environmental clean-up programmes. The problems of bioremediation for heavy metal-contaminated sites are very different from those of bioremediation for organic pollution, but intensive interdisciplinary collaboration in basic and applied research in this economically important field is expected to be very beneficial in the near future. It would be ideal if the bioremediation system maximised the extent and rate of degradation of waste materials, simultaneously minimising the level of toxic substances during the operation. (C) 2001 Elsevier Science B.V. All rights reserved.