In view of high toxicity, environmental mobility, non-biodegradability and stability of heavy metals, their removal becomes an absolute necessity. It is known that legal standard on environmental control are becoming strict and as a result the discharge of heavy metal into aquatic bodies is being rigorously controlled. So it is necessary to remove heavy metals from wastewater before discharge into the water and onto land. There are several methods used for the removal of heavy metals from waste discharges. In practice, the choice of one type of treatment versus another depends on several factors, including the form and concentration of metals in the wastewater, other constituents present, the extent of removal desired, environmental regulations pertaining to the discharge of the treated wastewater, associated capital and operating costs and the amount of sludges or residues generated and their disposal costs (Beszedits and Netzer, 1986). Now a days, chemical precipitation, membrane separation, electrolysis, ion exchange and adsorption are the widely used methods for the removal of heavy metals from wastewater. A brief discussion of these methods is given in the following sections.

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