ABSTRACT
The use of electrical and electronic equipment is increasing at a tremendous rate, and at the same time, this e-waste is one of the fastest-growing waste streams as a result of its decreased life span and use-and-throw culture. Recycling of this waste is important from aspects of both waste treatment and recovery of valuable metals. Hazardous metals in these wastes pose risk to human health and the environment, whereas high concentrations of precious metals make these wastes attractive in terms of economic recycling. Precious metals such as Ag, Au, Pt, etc. are present in these wastes and hence can act as secondary sources of these metals. Pyro- and hydrometallurgical methods create secondary pollution and hence this chapter focuses on the biohydrometallurgical route for recovery from various electronic wastes such as solders, printed circuit boards from computers and mobiles, etc. Various microorganisms involved in the process and their mechanisms of bioleaching are discussed in detail. Also, reactor studies, process optimization, and kinetic studies which help in improving the process efficiency of metal recovery are included in this chapter.
