Microorganisms in removal of heavy metals: Mechanisms, evaluation and case studies

• Published in: Bioprocess Sciences and Technology
• Main Author: 2-s2.0-84891990321
• Format: Book chapter
• Language: English
• Published: Nova Science Publishers, Inc. 2011
• Online Access: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84891990321&partnerID=40&md5=31f7158ec367170d59d3a85e0c72506a

The continuing presence of heavy metals both in the solid and liquid industrial wastes is of great concern. Currently practiced methods to remove heavy metals include landfill, cementation and incineration (for solid wastes) while carbon adsorption, ion exchange, filtration, precipitation, neutralization and solvent extraction are normally used for liquid waste. Even though these technologies offers cheap and efficient mode of waste management, the generation of large volumes of toxic sludge, the liberation of obnoxious gases and the possibility of chemical spillage makes it imperative to have an alternative treatment technique. The exploitation of microbial ability to survive in harsh environments such as wastewaters polluted with heavy metals is an alternative solution for heavy metals removal. These microbes would normally nullify the toxicity of heavy metals via the combination of one or more of the following processes; oxidation, reduction, accumulation or adsorption. However, before any attempt of using this technology at the industrial scale, various process arrangements need to be investigated at the laboratory, pilot and semi - commercial scales. Testing should also be carried out using simulated heavy metal solutions followed by the real industrial wastes. Besides this, the overall heavy metal biotransformation process can be elucidated using instrumental analysis such as using electron microscopy (metal deposition/translocation/accumulation, formation of microbial biofilm), EDAX (intracellular/extracellular metal deposition), EPR (paramagnetic condition, useful to justify biooxidation/reduction process), UV - vis, XAFS, voltammetry and FTIR (involvement of functional groups from the microbes in metal binding). © 2010 Nova Science Publishers, Inc. All rights reserved.