Review articleFrom electronic consumer products to e-wastes: Global outlook, waste quantities, recycling challenges
Graphical abstract
Introduction
Rapid advancements in material science, manufacturing processes, and electronic products have created global markets with rapid diffusion of technology to consumers. In recent years, the advancements in telecommunication and information technologies have increased globalization, making it possible to develop markets for the new products at scales larger than before in terms of data acquisition, product dissemination, technology application, consumer behavior, and market penetration. Increase in production of consumer products and their distribution to global markets combined with their affordability have created challenges for managing municipal solid waste (MSW), especially for the increasing quantities of discarded electronic consumer products. At the global scale, there are some inconsistencies in the understanding and application of the term electronic waste (e-waste) from both legislation and everyday use perspectives (UN Step, 2014). The applicable US regulations implemented by different states; Swiss Ordinance on the Return, Taking Back and Disposal of Electrical and Electronic Equipment (Swiss ORDEE); and European Union Waste of Electrical and Electronic Equipment (EU WEEE) Directive have some differences in their definition of waste electrical and electronic equipment (WEEE). For example, in the US, large and small household appliances (e.g., refrigerators, microwave ovens, coffee makers, toasters) are not considered as e-waste in most states while they are included under the EU WEEE Directive and the Swiss ORDEE regulations. The EU ORDEE Directive considers medical, surveillance, and automatic issuing machines as e-waste while these are not included under the Swiss ORDEE regulations but considered under separate regulations. Lighting equipment, electric/electronic tools, recreational equipment (e.g., treadmills, slot machines) and toys (e.g., electric train sets) are not included under the Swiss ORDEE regulations (since 2005); however, they included under the EU WEEE Directive. In general, e-waste includes old, end-of-life or discarded appliances using electricity. These include computers, consumer electronics (i.e., computers, LCD/CRT screens, mobile phones), large appliances (e.g., refrigerators, washer/dryers) and similar consumer products which have been disposed of by their original users.
Although both the development and diffusion of new technologies to consumers are occurring at faster rates; development of appropriate technologies and policies that address the management of e-waste are only at the beginning stages. There are limited controls on manufacturing of new products that include considerations for systematic and sustainable utilization of resources while continuing the development of new products, as these factors increase the production costs (Amankwah-Amoah, 2016, Singh et al., 2016). Some of the highly infused technologies have resulted in production of large quantities of e-waste with significant environmental challenges (e.g., lack of infrastructure for materials collection and recovery and associated environmental risks during e-waste handling/recycling) (Garlapati, 2016, Julander et al., 2014, Song and Li, 2014a, Song and Li, 2014b, Feldt et al., 2014).
Both formalized and unregulated regional small scale operations have been established for recovery operations of some metals with relatively high market values (Garlapati, 2016, Ruan and Xu, 2016, Davis and Garb, 2015). However, these operations; especially the uncontrolled entrepreneurial efforts; present challenges for safe handling of materials and work environments (Pinto, 2008, Robinson, 2009, Sepúlveda et al., 2010, Chen et al., 2011, Grant et al., 2013, Song and Li, 2014a, Song and Li, 2014b, Feldt et al., 2014). Tissue samples from residents living near the e-waste handling/processing areas and workers at the e-waste recycling facilities show high levels of pollutants associated with e-waste (i.e., PBBs, PBDEs, PCBs, PCDD/Fs, and heavy metals) (Song and Li, 2014a, Song and Li, 2014b, Wang et al., 2016, Lu et al., 2016). Waste management and chemical use practices at unregulated e-waste recycling operations can contaminate soils, plants and groundwater samples with significant increases in heavy metal concentrations (Zhang et al., 2012, Pradhan and Kumar, 2014).
This study reviews the challenges of managing e-waste; the need for developing controlled mechanisms and infrastructure for collection and recycling in view of the materials sustainability and global environmental quality. The quantities of e-waste have exponentially increased in the last several decades. The issues addressed include increasing e-waste quantities; increasing materials demand for manufacturing high tech products; recycling challenges for e-waste components; and global cross boundary transport of e-waste. The increasing needs for raw materials (especially for rare earth and minor elements) as well as increasing numbers of uncontrolled e-waste recycling operations contribute to the growing concerns for e-waste management. The cross boundary transport of e-waste at the global scale to areas with low labor costs creates environmental problems and health risk concerns at these locations. There is an increasing need for developing effective e-waste accounting mechanisms, waste management programs, and material recovery technologies.
Section snippets
Global outlook and increasing e-waste quantities
During the last 50 years, the world population has doubled, with balance tipping towards urbanization. Over half of the world population now lives in the urban areas. As a result of increasing population, increasing urbanization, and increasing life expectancy; the demands for water and crude oil have more than doubled in the last 50 years (Table 1).
Waste quantities have been increasing globally, however, at different rates in different counties. As presented in Table 2, per capita MSW generation
Materials demand for high tech products
Electronic devices have high demand for materials, especially for rare earth elements (REE) and minor minerals (MM) (Table 4, Fig. 1). Currently, there are no specific technical criteria and metrics for systematic evaluation and comparison of the relative demand of consumer products for materials; at the same time, allow an objective determination of the utilization of natural resources during their production. This creates opportunities for mass production of electronic products while creating
Recovery of materials from e-waste and recycling challenges
The design improvements that increase marketability and durability of high tech products (i.e., embedded systems and printed circuit boards) also create recycling challenges for separation of the components and materials recovery (Table 5). For example printed circuit boards (PCB), lamination of components and embedded systems increase durability of components while reducing their size. However, structurally integrated materials make it difficult for disassembly and recovery of materials. In
Global cross boundary e-waste transport
Management and fate of e-waste in different countries show significant differences between developed and underdeveloped countries. One of the most commonly used waste management options for e-waste is deposition in landfills. The potential incompatibility of materials deposited in landfills creates environments for formation of decomposition products which may be more hazardous and can enhance the mobility of metals and other organic compounds in landfills. Even after closure, landfill sites
Proactive vs reactive strategies for e-waste management
Technological advancements have resulted in rapid improvements in range of consumer products and manufacturing processes which in turn resulted in production and distribution of affordable systems at global scale. The availability and affordability of the new products have created a culture of rapidly changing high tech products, hence, reducing their use times by the consumers. However, from the environmental perspective, the necessary infrastructure and formalized mechanisms are not developed
Conclusions
During the last 50 years, waste characteristics have changed significantly as a result of technological advancements and changes in consumer goods, especially high tech products. Embedded systems, coatings, and amendments used to improve product quality and durability make it difficult to recover materials from the discarded electronic products. Increasing quantities of e-waste and the need for materials for manufacturing new products have increased the need for materials recovery and recycling
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