Biological Removal and Recovery of Metals from Waste Streams and Process Waters

Waste streams and process waters frequently contain metals of economic importance. Recovery of these resources would help to secure the supply of metals for industry and domestic consumption. Contaminants are also often a problem for further treatment of these waste streams and effluents, and need to be destroyed or removed to overcome potential pollution hazards. The development and optimisation of methods in biohydrometallurgy have opened new opportunities for the processing of low-grade waste materials and metal-containing effluents with potential for metal recovery. Bioleaching has been successfully applied in full-scale operations for reprocessing mine tailings and removing contaminants from concentrates, and promising results have been obtained for metallurgical waste and industrial residues. Biological treatment of process waters via bioprecipitation and biosorption has been used successfully in laboratory to full-scale operations to recover transition metals and remove contaminants from both acid mine drainage waters and mineral-processing effluents. Biological methods can also be selective and applicable for mine waters where metal concentrations are relatively small. The biological systems described in this chapter are flexible and can be integrated with chemical systems to overcome issues of metal and salt/solute toxicity. The combination of biological and chemical methods for metal recovery from secondary resources can help to secure metal supply and support the principle of zero-waste generation.