Treatment of Solid Waste Containing Metals by Biological Methods

Methods for the treatment of hazardous wastes are based on two main approaches: either hydrometallurgy or pyrometallurgy. Biological methods are considered viable environmental-friendly technologies and have been developed in the last years and have been associated with lower cost and energy requirements, in comparison with nonbiological processes. In these methods, it is important to find suitable microorganisms to degrade organic substances under favorable conditions to complete the treatment. The advantages of biotechnological treatment of hazardous wastes are biodegradation or detoxification of a wide variety of hazardous substances using natural microorganisms, as well as the availability of a wide range of biotechnological methods for the total destruction of these wastes without the production of secondary hazardous derivatives. However, to intensify the biological treatment, it is a necessary requirement to add nutrients and acceptors of electrons, including the control of the optimal conditions. Thus, biotechnology provides a solution for the ecological degradation of harmful heavy metals and toxic chemicals. The main purpose of this chapter is to present and discuss the biological methods used in the treatment of solid waste containing metals and the advantages and disadvantages of each method.