Biorecovery of Metals from Electronic Waste

Abstract

Electronic waste, termed interchangeably as e-waste and/or waste electrical and electronic equipment (WEEE), is the fastest-growing segment of solid waste. The global electronic waste generation has reached 42 million tons in 2014, and is expected to reach 50 million tons in 2020. In addition to being a hazardous waste type, WEEE also includes relatively high concentrations of metals. Modern devices contain up to 60 different elements at various concentrations, encompassing base metals, critical metals, and platinum group metals mixed in a complex matrix of metallic and non-metallic materials. The emergence of numerous new electronic products and occurrence of complex metal mixtures make this waste stream an important secondary source of metals. Improper and informal end-of-life (EoL) processing of electronic waste has detrimental consequences on the environment and public health. Microbial processing of metals from their primary ores is an established technology with many full-scale applications. Bioprocessing of waste materials for metal recovery, on the other hand, is an emerging and promising technology with low environmental impact and high cost-effectiveness. This chapter overviews bioprocessing of electronic waste as a secondary source of metals to recover metals. Additionally, biologically-driven metal extraction technologies, (e.g. bioleaching) and metal recovery techniques (e.g. biomineralisation) are reviewed.