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The Global Challenge of E‐Waste Generation
... According to the Global E-waste Monitoring 2020 report, the amount of e-waste produced increased from 9.2 Mt in 2014 to 53.6 Mt in 2019. Accordingly, it is predicted that the amount of e-waste is increasing globally, from approximately 61 million tons in 2023 to 74.7 million tons in 2030 [1,2]. The amount of e-waste, the fastestgrowing type of solid waste, constitutes approximately 5% of the annual solid waste produced worldwide [3]. ...
... There are three different criteria for the normalization procedure: (i) the bigger the better, (II) the smaller the better, and (III) the more normal the better [49]. In this study, (2) The bigger the better S∕N = − 10 log 10 1 n ...
This study focused on determining the optimum conditions for the maximum recovery of base and precious metals from printed circuit boards of end-of-life desktop computer motherboards using Taguchi-based grey relation analysis. In the first stage of the two-stage study, optimum conditions were investigated for the dissolution of base metals (copper and zinc) in waste printed circuit boards under high-pressure leaching. The dissolution of base metals was performed based on the L25 orthogonal array designed by Taguchi method. In the second step, designed according to Taguchi L9 orthogonal array to recover gold and silver from the solid remaining from the pressure-leaching process. Optimum combinations of parameters in both stages were determined using the multi-criteria optimization technique grey relationship analysis. In the experiments carried out in the determined optimum combinations, 99.62% of copper, 98.76% of zinc, 99.15 of silver and 85.82% of gold in waste printed circuit boards were recovered.
Graphical Abstract
... Despite these challenges, the field of metal recovery from E-waste presents numerous opportunities for innovation and growth. Advances in technology, such as the development of more efficient and selective leaching agents, the use of artificial intelligence and machine learning for optimizing recovery processes, and the integration of renewable energy sources into recycling operations, hold the potential to enhance the efficiency and sustainability of metal recovery [45], [46]. Moreover, the increasing demand for critical and precious metals in emerging technologies, such as electric vehicles, renewable energy systems, and advanced electronics, is likely to drive further investment and research in this area. ...
The increasing generation of electronic waste (E-waste) poses significant environmental and economic challenges, but it also presents an opportunity for resource recovery, particularly through the extraction of valuable metals. This...
Waste electrical and electronic equipment (WEEE) presents the dual characteristic of containing both hazardous substances and valuable recoverable materials. Mainly found in WEEE plastics, brominated flame retardants (BFRs) are a component of particular interest. Several actions have been taken worldwide to regulate their use and disposal, however, in countries where no regulation is in place, the recovery of highly valuable materials has promoted the development of informal treatment facilities, with serious consequences for the environment and the health of the workers and communities involved. Hence, in this review we examine a wide spectrum of aspects related to WEEE plastic management. A search of legislation and the literature was made to determine the current legal framework by region/country. Additionally, we focused on identifying the most relevant methods of existing industrial processes for determining BFRs and their challenges. BFR occurrence and substitution by novel BFRs (NBFRs) was reviewed. An emphasis was given to review the health and environmental impacts associated with BFR/NBFR presence in waste, consumer products, and WEEE recycling facilities. Knowledge and research gaps of this topic were highlighted. Finally, the discussion on current trends and proposals to attend to this relevant issue were outlined.
Copper ores, end-of-life electric and electronic equipment and car electronics can contain, besides Cu, substantial amounts of geochemically scarce companion elements. Geochemically scarce elements have an upper crustal abundance of <0.025 (weight)%. In view of resource conservation and reduction of pollution there is a case for near-zero waste processing. Improving the generation of ore concentrates and use of kinetic and thermodynamic data regarding smelting and converting can increase the production of geochemically scarce elements in the pyrometallurgical processing of copper ores. Reprocessing of copper ore processing residues can serve the generation of geochemically scare elements and the clean-up of matrix materials. Modularization of products, closed-loop take-back, including deposit-refund, systems for end-of -life products, and changes in the pre-processing thereof can be conducive to improved recovery of geochemically scarce elements from end-of-life electric and electronic equipment and car electronics. A comparatively large variety of geochemically scarce elements originating in end-of-life products can be recovered when in smelting lead and copper serve as collectors. Substantial research and development work is needed to optimize the co-production of geochemically scarce elements by hydrotechnology from copper ores and (mined) end-of-life products and to assess the potential of solvochemistry. There is technical scope for significant progress in the direction of near-zero waste processing in processing copper ores and (mined) end-of-life products, but for the realization of near-zero waste processing there are hurdles to be overcome related to marketability of outputs, safe handling of hazardous elements and company behavior. Also, the techno-economic potential of hydrotechnology and solvochemistry in extracting copper ores, copper ore processing residues and end-of-life products is uncertain. In view thereof, the feasibility near-zero waste production of copper and its geochemically scarce companion elements from copper ores and end-of-life electric and electronic equipment and car electronics is uncertain.
The composition of widespread electronic devices (mobile phone, computer mouse, keyboard, web-camera, monitor)
was studied by manual dismantling. The material flow analysis was conducted for e-waste components. For
the case study of Ukraine, five devices under investigation contain over 4 thousand tons / year resources. Most of
them (first of all, plastic and metal) can be easily recovered. The content of chemical elements in the components
of the electronic devices was determined by X-ray fluorescence analysis. Taking into account the mass of electronic
waste generated in Ukraine, the resource potential of metals was estimated. Most of metals are concentrated in
mobile phones and monitors (about 2000 tons/year). Apart from common metals, silver, molybdenum, vanadium,
rubidium, zirconium, antimony, yttrium, rhodium, bismuth, and gallium were also found.
Electronic e-waste (e-waste) is a growing problem worldwide. In 2019, total global production reached 53.6 million tons, and is estimated to increase to 74.7 million tons by 2030. This rapid increase is largely fuelled by higher consumption rates of electrical and electronic goods, shorter life cycles and fewer repair options. E-waste is classed as a hazardous substance, and if not collected and recycled properly, can have adverse environmental impacts. The recoverable material in e-waste represents significant economic value, with the total value of e-waste generated in 2019 estimated to be US $57 billion. Despite the inherent value of this waste, only 17.4% of e-waste was recycled globally in 2019, which highlights the need to establish proper recycling processes at a regional level. This review provides an overview of global e-waste production and current technologies for recycling e-waste and recovery of valuable material such as glass, plastic and metals. The paper also discusses the barriers and enablers influencing e-waste recycling with a specific focus on Oceania.
Spatial variations and mobility of mercury (Hg) and Hg associations with other potentially toxic elements (PTEs) were studied in soil samples from Alaba, the largest e-waste recycling site in Nigeria and West Africa. Total Hg concentration was determined in surface soil samples from various locations using cold vapour atomic absorption spectrometry (CVAAS) following microwave-assisted acid extraction, while sequential extraction was used to determine operationally defined mobility. The concentrations of the PTEs arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), manganese (Mn), mercury (Hg), nickel (Ni), lead (Pb) and zinc (Zn) metals were determined using inductively coupled plasma mass spectrometry (ICP-MS) following microwave-assisted digestion with aqua regia. Total Hg concentration ranged from < 0.07 to 624 mg/kg and was largely dependent on the nature and intensity of e-waste recycling activities carried out. Mobile forms of Hg, which may be HgO (a known component of some forms of e-waste), accounted for between 3.2 and 23% of the total Hg concentration, and were observed to decrease with increasing organic matter (OM). Non-mobile forms accounted for >74% of the total Hg content. In the main recycling area, soil concentrations of Cd, Cd, Cu, Hg, Mn, Ni, Pb and Zn were above soil guideline values (Environment Agency in Science Report, 2009; Kamunda et al., 2016). Strong associations were observed between Hg and other PTEs (except for Fe and Zn) with the correlational coefficient ranging from 0.731 with Cr to 0.990 with As in April, but these correlations decreased in June except for Fe. Hazard quotient values > 1 at two locations suggest that Hg may pose health threats to people working at the e-waste recycling site. It is therefore recommended that workers should be investigated for symptoms of Hg exposure.
With the development of dark polymers for industrial sorting technologies, economically profitable recycling of plastics from Waste Electrical and Electronical Equipment (WEEE) can be envisaged even in the presence of residual impurities. In ABS extracted from WEEE, PP is expected to be the more detrimental because of its important lack of compatibility. Hence, PP was incorporated to ABS at different rates (2 to 8 wt%) with a twin-screw extruder. PP was shown to exhibit a nodular morphology with an average diameter around 1–2 µm. Tensile properties were importantly diminished beyond 4 wt% but impact resistance was decreased even at 2 wt%. Both properties were strongly reduced as function of the contamination rate. Various potential compatibilizers for the ABS + 4 wt% PP system were evaluated: PPH-g-MA, PPC-g-MA, ABS-g-MA, TPE-g-MA, SEBS and PP-g-SAN. SEBS was found the most promising, leading to diminution of nodule sizes and also acting as an impact modifier. Finally, a Design Of Experiments using the Response Surface Methodology (DOE-RSM) was applied to visualize the impacts and interactions of extrusion temperature and screw speed on impact resistance of compatibilized and uncompatibilized ABS + 4 wt% PP systems. Resilience improvements were obtained for the uncompatibilized system and interactions between extrusion parameters and compatibilizers were noticed.
More than 200 kg real waste electrical and electronic equipment (WEEE) shredder residues from a German dismantling plant were treated at 650 °C in a demonstration scale thermochemical conversion plant. The focus within this work was the generation, purification, and analysis of pyrolysis oil. Subsequent filtration and fractional distillation were combined to yield basic chemicals in high purity. By means of fractional distillation, pure monocyclic aromatic fractions containing benzene, toluene, ethylbenzene, and xylene (BTEX aromatics) as well as styrene and α-methyl sty-rene were isolated for chemical recycling. Mass balances were determined, and gas chromatography mass spectrometry (GC-MS) as well as energy dispersive X-ray fluorescence (EDXRF) measurements provided data on the purity and halogen content of each fraction. This work shows that thermochemical conversion and the subsequent refining by fractional distillation is capable of recycling WEEE shredder residues, producing pure BTEX and other monocyclic aromatic fractions. A significant decrease of halogen content (up to 99%) was achieved with the applied methods.
Resource efficiency strategies are emerging on policy agendas worldwide. Commonly, resource efficiency policies aim at decreasing losses at the waste management stage and, thus, diverge from public interest in more comprehensive resource efficiency measures that include a focus the earlier material life cycle stages. Just in recent years, improvements in the lifetimes of products and increased repair and reuse ability have become policy objectives in some countries. However, the effectiveness of policy measures is usually not assessed, even though it is crucial to support informed policy‐making and efficiently decrease the environmental impact of resource use. In this paper, we provide such an assessment for the copper cycle, the third most consumed metal with sharply increasing demand. Under current practices, in Western Europe and North America, 50% and 44% of the losses by 2050 occur at end‐of‐life collection, and only 2% of losses take place at the recovery stage; in Middle East and Africa for 19% and 54%, respectively. By 2050, most copper would be lost in China with a proportion of 58%. We evaluate the resource efficiency by quantifying the two key parameters, circularity and longevity, that is, how often and how long the material is in use in the anthroposphere. Our results show that the current global longevity of high‐grade copper is 47 ± 2.5 years, and a copper atom is used in 2.1 ± 0.1 applications on average. Ambitious political measures across the life cycle can increase longevity by 85% and circularity by 45%.
Conducting polymers are extensively studied due to their outstanding properties, including tunable electrical property, optical and high mechanical properties, easy synthesis and effortless fabrication and high environmental stability over conventional inorganic materials. Although conducting polymers have a lot of limitations in their pristine form, hybridization with other materials overcomes these limitations. The synergetic effects of conducting polymer composites give them wide applications in electrical, electronics and optoelectronic fields. An in-depth analysis of composites of conducting polymers with carbonaceous materials, metal oxides, transition metals and transition metal dichalcogenides etc. is used to study them effectively. Here in this review we seek to describe the transport models which help to explain the conduction mechanism, relevant synthesis approaches, and physical properties, including electrical, optical and mechanical properties. Recent developments in their applications in the fields of energy storage, photocatalysis, anti-corrosion coatings, biomedical applications and sensing applications are also explained. Structural properties play an important role in the performance of the composites.
Recycling of electric and electronic waste products (e-waste) which amounted to more than 50 million metric tonnes per year worldwide is a massive and global operation. Unfortunately, an estimated 70-80% of this waste has not been properly managed because the waste went from developed to low-income countries to be dumped into landfills or informally recycled. Such recycling has been carried out either directly on landfill sites or in small, often family-run recycling shops without much regulations or oversights. The process traditionally involved manual dismantling, cleaning with hazardous solvents, burning and melting on open fires, etc., which would generate a variety of toxic substances and exposure/hazards to applicators, family members, proximate residents and the environment. The situation clearly calls for global responsibility to reduce the impact on human health and the environment, especially in developing countries where poor residents have been shouldering the hazardous burden. On the other hand, formal e-waste recycling has been mainly conducted in small scales in industrialised countries. Whether the latter process would impose less risk to populations and environment has not been determined yet. Therefore, the main objectives of this review are: 1. to address current trends and emerging threats of not only informal but also formal e-waste management practices, and 2. to propose adequate measures and interventions. A major recommendation is to conduct independent surveillance of compliance with e-waste trading and processing according to the Basel Ban Amendment. The recycling industry needs to be carefully evaluated by joint effort from international agencies, producing industries and other stakeholders to develop better processes. Subsequent transition to more sustainable and equitable e-waste management solutions should result in more effective use of natural resources, and in prevention of adverse effects on health and the environment.
The investigation on the transboundary shipment of used and waste electrical and electronic equipment from developed countries is a well-studied subject with regard to the environmental and health impacts in the destination countries when it reaches end-of-life. Prior research has ranked Ireland the 8th highest source of used electrical and electronic equipment (UEEE) into Nigeria, with roll-on roll-off (RoRo) vehicles as the largest carrier (Odeyingbo 2017). This study presents the first comprehensive port of origin estimation of UEEE export shipments from Ireland in RoRo vehicles. This was obtained by using a ‘person in the port’ involving vehicle and enforcement document inspections at the Ringaskiddy port in Cork, Ireland. By scaling sampling data to annual shipment figures, it was estimated that 17,319 kg of UEEE are currently exported from Ireland annually and that around 1 in 5 vehicles exported contain UEEE. Additionally, the type of UEEE and frequency of shipments show certain equipment are high in demand at destination country. By using the Nigerian second-hand websites, the annual shipments were valued at approximately €147,225. The results obtained from this study suggests a significant reduction in UEEE exported from previous studies and highlights an opportunity for further research in additional ports of origin, as well as the examination of the shipping process, cost, and verification of functionality. Additionally, the straightforward methods provide better understandings of UEEE flows as this is significant to all stakeholders concerned with the regulation, enforcement, and safety of UEEE shipment.
Stratospheric ozone depletion and global temperature elevation resulting from the discharge of refrigerants from conventional cooling systems have demonstrated to be a menace to animal kingdom around the globe. International pacts viz. Montreal and Kyoto Protocols were designed and enforced on technologically developed and developing countries to restrain the manufacture and consumption of these halogen-laden man-made working mediums bearing significant Ozone depleting potential (ODP) and Global warming potential (GWP), followed by phasing out the relative impact of these climate gases out entirely as early as possible. In response to the Kigali agreement to the Montreal Protocol, momentous researches are being carried out across the globe with a compulsion to find green refrigerants proficiently operating in innovative refrigeration techniques in meeting the growing demands, harmonizing the paradigm shift. This paper authenticates the hitches related to the orthodox halogenated entrants and critically reviews the reported literatures in the past few decades for the choice of credible substitutes considering environmental, economic and energy competent aspects. The present review emphasizes on the feasibility of the most suitable long term surrogate for the cooling system based on the thermo-physical properties of various refrigerants.
The objective of this study is to assess the feasibility of a sustainable “reverse logistics” processes of the cell phone manufacturing industry in Brazil. To this end, it carried out a case study on a cell phone refurbishment company that is responsible for the reconditioning of cell phones; the company also receives returned cell phones from one of the largest cell phone manufacturers in Brazil. Another company collects waste from the refurbishing process and recycles the precious metals and plastic from the electronic electronics components. A number of propositions were made and confirmed through an interview conducted with the owner of the refurbishment company. It is concluded that the main reasons for the return of the product are the “buy back” process, irreparable and at the end of life cell phones. And from cell phones received from the manufacturer, it is estimated that about 15% of the products are returned to the market without remanufacturing, 15% are used for the salvaged components, and 70% are reconditioned for return to the market. The refurbishing process proved to be profitable because the annual cash flow approached USD 2.5 million and generated a profit of USD 226 thousand for the refurbishment company and prevents a discard of 4.5 tons/year of EEW, which gives an efficiency of 88% of all the cell phone manufactured by the company. Thus, the reverse logistics chain of the cellular manufacturing industry in Brazil has proved to be very sustainable, with zero net EEW.
Polybrominated diphenyl ethers (PBDEs) are released from the recycling process of PBDE-containing waste printed circuit board (WPCB), but studies on the mechanism of PBDE emission and migration are limited. In this study, PBDE concentrations in particulate matter (PM), dust, and fumes collected in a pilot-scale workshop for the WPCB de-soldering process were measured, and PBDE emission after gas treatment was estimated. The results showed that the mean concentrations of ∑8PBDEs in TSP and PM2.5 in the workshop were 20.3 ng/m3 (24.7 μg/g) and 16.1 ng/m3 (115 μg/g), respectively. In practice, the fumes containing gaseous and particulate PBDEs were treated by the combination of alkaline solution absorption and activated carbon adsorption. Compared to PBDE concentration in workshop floor dust (2680 ng/g), PBDE concentrations in solution scum (68,000 ng/g) and hood inside dust (20,200 ng/g) were condensed. The concentrations of ∑6PBDEs at the stack outlet (416 pg/m3) after gas treatment were lower than those in the stack pipe (1310 pg/m3) and hood inside (7440 pg/m3). The PBDEs in fumes were removed through physical adsorption of alkaline solution and activated carbon, and solution scum constituted the main mass discharges of PBDEs. The emission factor of PBDEs at the stack outlet was 47.3 ng ∑6PBDEs/kg WPCB. As a result, the WPCB de-soldering process is an important source of PBDE pollution, and gas treatment of solution absorption and activated carbon adsorption can reduce PBDE emission to some extent.
The effective management of solid waste, including waste electrical and electronic equipment (WEEE) in developing countries poses significant challenges. This paper reports on the development and utilization of a multi-criteria tool to improve the management of WEEE in Agbogbloshie, in Ghana. The tool was able to successfully evaluate key economic, social and environmental factors faced by workers and to suggest areas for improvement. In particular, the evaluation and comparison of different scenarios suggested that the best solution is the evolution from informal to formal management of WEEE, with workers provided with personal protective equipment, and the introduction of refurbishment activities, with the sale of components in the second-hand market. While it would require further use in other contexts, the tool could be adapted and employed for a range of other waste streams and in other developing countries.
The production of electrical and electronic equipment is a fast-growing industrial sector, which also results in growing generation of waste electrical and electronic equipment (WEEE). An efficient separation is a prerequisite in order to achieve a high recyclability of WEEE plastics and produce pure types of plastics. The scope of the paper is to investigate the influence of particle size on the recyclability of post-shredding plastic fractions from WEEE pre-processing. For this purpose, different shredding technologies for WEEE, their output particle size, the sorting technologies and their required input particle size were investigated and compared. Sample analysis of plastic flakes provided from pre-processors is performed. The results show that the different sorting technologies require different particle size ranges for efficient separation. Three scenarios were investigated in order to identify optimal output particle sizes for improved plastic recycling. The results suggest that a particle size between 10–20 mm increases the sorting efficiency and thus recyclability of the plastic fractions and minimizes the losses into fines. Further recommendations to pre-processors and recyclers include improving the communication between the end-of-life actors, to standardize the particle size range (10–20 mm) as well as not to dispose the fine fraction but to find recyclers operating appropriate fines sorting technologies.
In this paper, a review of the most recent technologies for indium recovery from waste flat panel displays is provided. Differently from the other fractions obtained after primary dismantling (such as plastic casings, printed circuit boards, metallic fractions and the fluorescent lamps) which have assessed recycling routes, the indium-containing panels are currently not properly treated and indium recovery from this residual fraction at industrial scale is still a challenge. Indium has been included in a list of "critical raw materials" by the European Commission and its recovery from secondary sources is gaining increasing attention among the scientific community. Its recovery is mostly performed at laboratory scale via pyro-and hydrometallurgical techniques and a very few examples of pilot-plant solutions can be found in the available literature. FPDs represent a source of valuable materials: besides indium, they contain glass and the polarizing films, which recovery could lead to both economic and environmental advantages. Suggestions for improvement are here provided to close the loop of flat panel displays recycling, in accordance with the principles of Circular Economy.
At present, waste mobile phone is considered to be one of the fastest-growing obsolete items in the stream of electronic waste (e-waste). Toxic substances such as heavy metals and brominated flame retardants (BFRs) have been widely added to plastics used in electrical and electronic equipment (EEE). The recent technological revolution in electronic appliances combined with high and growing consumption has caused a huge generation of waste electrical and electronic equipment (WEEE). Therefore, e-waste plastics are considered to be one of the fastest-growing waste streams globally. In this study, we examined the hazardous substances in the plastic components of waste mobile phones and then applied the USEtox life cycle impact assessment (LCIA) model to determine the impacts on human health. Specifically, various plastic parts separated from waste mobile phones (n = 20) were collected and then, we used standard tests to characterize the heavy metals and brominated flame retardants. The mean and range of the results are 2207.7 μg/kg (503.9-11569.9 μg/kg) for Pb, 91.6 μg/kg (8.8-464.4 μg/kg) for Cd, 13.7 μg/kg (1.6-58.9 μg/kg) for Be, 7203.3 μg/kg (117-69813 μg/kg) for Sb, 471.3 μg/kg (143.4-2351.3 μg/kg) for As, 1.5 mg/kg (2.1-12.5 mg/kg) for Hg and 523.7 mg/kg (27.1-3859 mg/kg) for Cr. The BFRs-a sum Polybrominated Biphenyls, Polybrominated Diphenyl Ethers and Hexabromocyclododecane-were not detected except for two samples, which was an average of 234.5 μg/kg for nona-BDE and deca-BDE. The total bromine (Br) concentration varied from 0 to 471 mg/kg (average value of 87.9 mg/kg) , while Tetrabromobisphenol A (TBBP-A) showed an average concentration of 214.3 μg/kg. In the case of potential human health risks, Hg contributed the major risk for carcinogens and non-cancer disease in the plastics, but the contribution of Pb was also significant. In the case of eco-toxicity, Cr posed the most significant risks in the plastics. Overall, the results show that the toxic substances are below the limit values of substances regulated in the RoHS Directive in China and Europe. However, the results of LCIA highlight the growing importance to avoid the open burning practices of e-waste plastics that contain Hg, Pb, Cr ad Sb. Additionally, the results set a new database for the e-waste plastics recycling industry and provide information for ecodesign in EEE production.
The informal e-waste recycling sector has potential for both harmful environmental releases and environmental benefits associated with avoided emissions from recovered materials. Four household appliances (washing machine, refrigerator, Cathode Ray Tube (CRT) television, fan) were selected for a combined Material Flow Analysis and Life Cycle Assessment (LCA) analysis of their end-of-life treatment. Data collection took place in an informal e-waste recycling community in Thailand, recording the weight of materials recovered for each appliance, along with the number of each appliance recycled for one entire village. The LCA determined the avoided emissions and damages (human health, ecosystem quality, climate change, and resource use) per kg material recovered, per product, and for an entire recycling community, with a benefit of 2.7 to 25.4 kg CO2 eq avoided per product piece. Informal e-waste recycling appears relatively efficient in material recovery and economically beneficial. Recyclers recovered 93% or more of the original mass of the products. Just over 460,000 kg of waste devices were processed each year, with a net value added of 2.1 million Thai Baht. Each year, the normalized environmental net benefits amount to 0.2 DALYs for human health, 60,000 kg CO2 eq in climate change impacts, and nearly 400,000 MJ in avoided resource damages each month. Informal e-waste recycling was found to have net benefits in terms of avoided emissions, in particular due to recovery of PCBs, copper, steel and plastic with the exception of improper disposal of hazardous materials of lead in landfilled CRT screens and burned cables.
Polybrominated diphenyl ethers (PBDEs) are flame retardants widely used to manufacture several commercial plastic products. The major homologue in commercial PBDE mixtures are listed in the Stockholm Convention on Persistent Organic Pollutants and are scheduled for global elimination. Hence, to understand more about unintentional contamination of plastic recycling stream by restricted PBDEs, we examined 540 small plastic consumer products (1139 components after dismantling), including children's toys, purchased in 18 countries (mainly Japan) between 2015 and 2019. Handheld X-ray fluorescence analysis revealed that 219 plastic components (19% of the total samples) contained bromine at a concentration of ≥30 mg kg⁻¹. Chemical analysis of these bromine-positive components revealed that 109 pieces (9.6% of the total), mainly those made of black-colored plastic, contained PBDEs at concentrations ranging between 35–10,000 mg kg⁻¹, with the maximum contribution from decabromodiphenyl ether (decaBDE). These PBDE concentrations were insufficient to impart flame retardancy, suggesting that the recycled plastic used to manufacture these consumer products probably originated from electronic waste, the manufacture of which was the primary use of commercial decaBDE mixtures. PBDEs were also found in secondary raw plastic materials and their final products obtained in India in 2019, demonstrating that plastics containing decaBDE end up in products where they serve no functional purpose. To contribute to the circular economy, the recycling of plastic waste in end-of-life products should be promoted. However, urgent action is needed to prevent plastic additives of concern, including PBDEs, from entering new products used in daily lives, particularly those used by children.
Glass is a material inextricably linked with human civilization. It is also the product of an energy intensive industry. About 75%–85% of the total energy requirements to produce glass occur when the raw materials are heated in a furnace to more than 1500 °C. During this process, large volumes of emissions arise. The container and flat glass industries, which combined account for 80% of total glass production, emit over 60 million tonne of CO2 per year. However, environmental issues relating to the glass industry are not just limited to the manufacturing stage, but also from raw materials extraction, which impacts local ecosystems and creates other environmental challenges associated with tailing ponds, waste disposal and landfills. This systematic review poses five questions to examine these issues and themes: What alternatives exist to abate the climate effects of glass and thus make the full life cycle of glass more sustainable? What are the key determinants of energy and carbon from glass? What technical innovations have been identified to make glass manufacturing low to zero carbon? What benefits will amass from more carbon-friendly process in glass manufacturing, and what barriers will need tackling? To examine these questions, this study presents the findings of a comprehensive and critical systematic review of 701 studies (and a shorter sample of 375 studies examined in depth). A sociotechnical lens is used to assess glass manufacturing and use across multiple sectors (including buildings, automotive manufacturing, construction, electronics, and renewable energy), and options to decarbonize. The study identifies a number of barriers ranging from financial to infrastructural capacity, along with high potential avenues for future research.
Uncontrolled electronic-waste recycling processes have induced serious
environmental pollution and human health impacts. This paper reviewed studies on
the wide range of toxic chemicals through the use of primitive recycling techniques,
their transfer to various ecological compartments, and subsequent health impacts.
Results indicated that local food items were heavily polluted by the pollutants
emitted, notably heavy metals in vegetables, rice, fish and seafood, and persistent
organic pollutants (POPs) in livestock. Dietary exposure is the most important exposure pathway. The associations between exposure to e-waste and high body
burdens of these pollutants were evident. It seems apparent that toxic chemicals
emitted from e-waste activities are causing a number of major illnesses related to
cardiovascular, digestive and respiratory systems, according to the information
provided by a local hospital (Taizhou, an e-waste recycling hot spot in China). More
epidemiological data should be made available to the general public. It is envisaged
that there are potential dangers of toxic chemicals passing on to the next generation
via placental transfer and lactation. There is a need to monitor the development and
health impacts of infants and children, born and brought up in the e-waste sites.
With the digital revolution across the world, including in low- and middle-income countries (LMICs) like Bangladesh, the global burden of electronic waste (e-waste) is increasing. Consequently, the environmental and human health implications of informal e-waste recycling practices in LMICs are becoming a cause for concern. Here we report the indoor dust and air contamination from e-waste derived heavy metals in the e-waste recycling shops in Dhaka, the capital of Bangladesh. Representative heavy metals including Pb, Cu, Ni, Cr, and Mn were measured in dust and air samples collected from three different e-waste shops located in two different sites in Dhaka. Concentrations of these heavy metals were found to be as much as orders of magnitude higher in the e-waste sites than in areas with no e-waste recycling activities. The geo-accumulation index (Igeo) calculated for these metals also indicated moderate to severe pollution of the e-waste shops, especially for Pb and Cu. The calculated health quotient (HQ) and hazard index (HI) for these metals indicate towards potential severe health risk of the workers due to the release and exposure to Pb from the e-wastes. These results emphasize the need for more direct evidence of contaminant exposure, body burden, and health impacts of the e-waste workers in Bangladesh, along with the need for interventions to ensure the health and safety of these workers.
Sustainable management of waste electrical and electronic equipment (WEEE) offers a significant opportunity for resource recovery. However, the generation of plastics in WEEEs and the environmental impacts related to subsequent recycling have not been well addressed. This study estimates the generation volumes of plastics that are recycled from five typical kinds of WEEEs in China and analyzes the environmental performance of WEEE plastics recycling using life cycle assessment (LCA). The results show that recycled plastics from WEEEs increased from 231.6 kt in 2010 to 565.8 kt in 2018, by an average rate of 11.8% per year, with acrylonitrile-butadiene-styrene (ABS), polypropylene (PP) and polystyrene (PS) being the three main components. In 2018, the estimated total electricity consumption and greenhouse gas emissions caused by Chinese WEEE plastics recycling reached 238.6 million kWh and 712.1 kt CO2 eq, primarily due to energy consumption, transportation and WEEE disassembling processes. Based on the results, we find that recycled plastics from WEEEs demonstrate better performance on most environmental aspects except for ozone depletion as compared to the production of virgin plastics. The ongoing ozone-depleting emissions imply an urgent need for additional actions to minimize potential refrigerant leakage in WEEE plastics recycling. This study provides essential information about the existing WEEE plastics recycling practices in China and offers valuable implications to enhance the recycling of plastic materials from WEEEs and achieve sustainable WEEE management.
The management of waste electrical and electronic equipment (WEEE) represents one of the main environmental challenges on a global scale, due to the rapid growth of this type of waste and the risk it poses to both human health and the environment. Decision makers depend on reliable estimates of the generation of WEEE and the quantification of its environmental impact. However, limited data regarding the amount of equipment in use, annual sales, and the lifespan of electrical and electronic equipment pose important limitations to this assessment. In response to this challenge, this paper develops a combined dynamic material flow analysis and life cycle assessment approach to estimate the volume of end-of-life refrigerators in Colombia and measure their environmental impact. First, the dynamic MFA model is developed to calculate the number of end-of-life refrigerators between 1935 and 2050. Then, the environmental impact is estimated using the CO2 emissions generated in each of the pathways of final disposal at the end of the refrigerators’ useful life. The results highlight the importance of the formal refrigerator recycling system in Colombia, since this achieves a saving of approximately three million tonnes of CO2 emissions during the period of evaluation. They also show that delivering refrigerators to informal recyclers or throwing them into open-air dumps or bodies of water generates a considerable environmental impact in comparison. Additionally, these alternative scenarios imply the loss of more than two hundred thousand tonnes of recyclable material.
Spent fluorescent lamps glass (SFLG) waste, manually and mechanically processed in a lamps waste treatment plant, was used to partially replace up to 50 wt% Portland cement (PC). Both waste types exhibited similar pozzolanic activity. The mortars containing up to 35 wt% SFLG met the specifications for other pozzolanic materials (e.g. fly ash) and, after 90 curing days, their compressive strength values were similar to or higher than those of the 100% PC sample (58.8 MPa). Our results provide an alternative reutilization process for this hazardous waste to reuse SFLG as-received (no washing to reduce mercury) and contributes to less PC use.
A huge increase of waste of electrical and electronic equipment (WEEE) is observing everywhere in the world. Plastic component in this waste is more than 20% of the total and allows important environmental advantages if well treated and recycled. The resource recovery from WEEE plastics is characterised by technical difficulties and environmental concerns, mainly related to the waste composition (several engineering polymers, most of which containing heavy metals, additives and brominated flame retardants) and the common utilisation of sub-standard treatments for exported waste.
An attributional Life Cycle Assessment quantifies the environmental performances of available management processes for WEEE plastics, those in compliance with the European Directives and the so-called substandard treatments. The results highlight the awful negative contributions of waste exportation and associated improper treatments, and the poor sustainability of the current management scheme. The ideal scenario of complete compliance with European Directives is the only one with an almost negligible effect on the environment, but it is far away from the reality. The analysed real scenarios have strongly negative effects, which become dramatic when exportation outside Europe is included in the waste management scheme. The largely adopted options of uncontrolled open burning and illegal open dumping produce huge impacts in terms of carcinogens (3.5·10+7 and 3.6·10+4 person⋅year, respectively) and non-carcinogens (1.7·10+8 and 2.0·10+6 person⋅year) potentials, which overwhelm all the other potential impacts. The study quantifies the necessity of strong reductions of WEEE plastics exportation and accurate monitoring of the quality of extra-Europe infrastructures that receive the waste.
Nowadays, old electrical and electronic gadgets are being replaced constantly by newer versions resulting in huge amounts of waste electronic and electrical products that are collectively termed e-waste. It is estimated that 95% of e-waste recycling in India is done by the informal sector at the cost of their health and the environment. Very little data and no descriptions of recycling processes in the formal sector in India were available in the literature. The objective of this study was to evaluate the status of formal and informal e-waste recycling facilities in India. Seven authorized e-waste handling facilities in West Bengal, Maharashtra, Karnataka and Delhi were visited and most were involved in dismantling work only. In all cases, metals, plastic and glass are recovered from e-waste in compliance with environmental legislation. Challenges faced by the formal sector include lack of awareness among people and very few collection centers throughout the country. Quantification of e-waste generated in India was difficult as imported second-hand electrical and electronic gadgets cannot be separated for electronic waste. There is no mechanism for collecting data regarding e-waste generation in the states or at the Central government level. It is likely that published estimates are based on the indigenous production and import of electrical and electronic goods. The current installed e-waste handling capacity of 11 × 10⁵ tons/year of e-waste in the country is woefully inadequate and needs to be enhanced as the minimum requirement is estimated to be 22 × 10⁵ tons/year of e-waste.
Liquid crystal monomers (LCMs), widely used in liquid crystal displays, have been recognized as a class of potential emerging pollutants in the environment. However, their atmospheric fate and toxicity involved in the atmospheric transformation have been rarely investigated. Herein, we employed quantum chemical calculation and computational toxicology to systematically investigate the âOH-initiated oxidation kinetics and mechanism of three LCMs (4-cyanophenyl 4-ethylbenzoate (CEB), 4-cyano-3-fluorophenyl 4-ethylbenzoate (CEB-F), and 4-cyano-3,5-difluorophenyl 4-ethylbenzoate (CEB-2F)) in the atmosphere, and the toxicity of CEB-2F (as an example) during transformation. The calculated gaseous rate constants and half-lives for CEB, CEB-F, and CEB-2F at 298 K were in the range of (0.9-1.4) × 10-12 cm3 molecule-1 s-1 and 5.7-8.9 days, respectively, suggesting that these LCMs had atmospheric persistence and long-range transport potential. The transformation products (TPs) of CEB-2F were found to be similar to those experimentally determined in âOH oxidation of particulate LCMs. Furthermore, some TPs were predicted to exhibit enhanced toxicity compared with the parent LCM, indicating that much attention should be also paid to their risks besides the original LCMs. These results would be helpful for the LCM regulation and provide guidance on their development and safe application.
Humanity has come to depend on synthetic, factory made gases that have extremely significant global warming potential. Fluorinated greenhouse gases, or F-gases, such as hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulfur hexafluoride (SF6), and nitrogen trifluoride (NF3) have been termed “super pollutants” and “super greenhouse gases” given their severe and powerful impact on the climate. They are the most potent greenhouse gases known to modern science, with global warming potentials far greater than carbon dioxide, some up to almost 24,000 times more so. Troublingly, they are also the fastest growing class of greenhouse gas emissions around the world, especially in developing countries. Research suggest that almost 40% of their emissions by 2050 will fall outside the scope of international agreements such as the Paris Accord, Montreal Protocol and Kigali Amendment. Without comprehensive and sustained interventions, uncontrolled growth in F-gas emissions could offset all of the gains made by the Clean Development Mechanism of the Kyoto Protocol, or the cornerstone of existing international climate governance, the Nationally Determined Contributions of the 2015 Paris Accord. This review asks: What options are available to mitigate the environmental impacts of F-gases and thus make their manufacturing or disposal far more sustainable? What technical solutions and innovations exist to make their industrial usage low to zero carbon? What benefits will accrue from F-gas mitigation, and what barriers will need addressed? It undertakes a comprehensive and critical review of more than 140,000 sources of evidence, and a short list of 855 studies on the topic. It utilizes a sociotechnical lens that examines the manufacturing and use of F-gases across multiple sectors (including refrigeration, electronics manufacturing, non-ferrous metals processing, and applications in consumer goods) and components of its lifecycle (including not only manufacturing, but also use, disposal and destruction). We find that there are several policies and regulations that can be employed to address this already serious and growing climate change challenge.
Waste electrical and electronic equipment (WEEE) comprises a globally important waste stream due to the scarcity and value of the materials that it contains; annual generation of WEEE is increasing by 3–5% per annum. The effective management of WEEE will contribute critically to progress towards (1) realisation of the United Nations’ Sustainable Development Goals, (2) a circular economy, and (3) resource efficiency. This comprehensive review paper provides a critical and contemporary examination of the current global situation of WEEE management and discusses opportunities for enhancement. Trends in WEEE generation, WEEE-related policies and legislation are exemplified in detail. Four typical future WEEE management scenarios are identified, classified and outlined. The European Community is at the forefront of WEEE management, largely due to the WEEE Directive (Directive 2012/19/EU) which sets high collection and recycling targets for Member States. WEEE generation rates are increasing in Africa though collection and recycling rates are low. WEEE-related legislation coverage is increasing in Asia (notably China and India) and in Latin America. This review highlights emerging concerns, including: stockpiling of WEEE devices; reuse standards; device obsolescence; the Internet of Things, the potential for collecting space e-debris, and emerging trends in electrical and electronic consumer goods. Key areas of concern in regard to WEEE management are identified: the partial provision of formal systems for WEEE collection and treatment at global scale; further escalation of global WEEE generation (increased ownership, and acceleration of obsolescence and redundancy); and absence of regulation and its enforcement. Measures to improve WEEE management at global scale are recommended: incorporation of circular economy principles in EEE design and production, and WEEE management, including urban mining; extension of WEEE legislation and regulation, and improved enforcement thereof; harmonisation of key terms and definitions to permit consistency and meaning in WEEE management; and improvements to regulation and recognition of the informal WEEE management sector.
The rise of electronic waste (e-waste) generation around the globe has become a major concern in recent times and its recycling is mostly focused on the recovery of valuable metals, such as gold, silver, and copper, etc. However, e-waste consists of a significant weight fraction of plastics (25 – 30%) which are either discarded or incinerated. There is a growing need for recycling of these e-waste plastics. The majority of them are made from high-quality polymers (composites), such as acrylonitrile butadiene styrene (ABS), high impact polystyrene (HIPS), polycarbonate (PC), polyamide (PA), polypropylene (PP) and epoxies. These plastics are often contaminated with hazardous materials, such as brominated flame retardants (BFRs) and heavy metals (such as Pb and Hg). Under any thermal stress (thermal degradation), the Br present in the e-waste plastics produces environmentally hazardous pollutants, such as hydrogen bromide or polybrominated diphenyl ethers/furans (PBDE/Fs). The discarded plastics can lead to the leaching of toxins into the environment. It is important to remove the toxins from the e-waste plastics before recycling. This review article gives a detailed account of e-waste plastics recycling and recovery using thermochemical processes, such as extraction (at elevated temperature), incineration (combustion), hydrolysis, and pyrolysis (catalytic/non catalytic). A basic framework of the existing processes has been established by reviewing the most interesting findings in recent times and the prospects that they open in the field recycling of e-waste plastics.
Electronic products are an essential part of modern society, but their importance has perhaps never been as palpable as when the COVID-19 pandemic forced almost every aspect of human interaction to go online. However, the pandemic also revealed that the supply chains that provide crucial raw materials for manufacturing electronics are increasingly vulnerable to social, geopolitical, and technical disruptions. These vulnerabilities are likely to escalate in the future, due to global health crises, natural disasters, and global political instability, all of which will be magnified by looming climate change impacts. This study investigates potential supply chain disruption risks in the electronics sector by applying metrics that capture supply, demand, socio-political, and environmental risks in a multi-criteria framework to almost 40 metals and minerals that provide critical functionality to electronic products. Results illustrate that the material risks varied with the potential nature of the disruption. For example, in scenarios where disruptions led to price volatility or weakening of environmental regulations, highest risks were observed for precious metals such as gold, rhodium, platinum, and palladium. On the other hand, in scenarios where disruptions led to supply pressures or geopolitical tensions, cobalt, gallium, and key rare earth elements exhibited the highest risks. These metals are characterized by energy-intense manufacturing and highly concentrated geographic production, suggesting that recycling and supply chain diversification may alleviate some of the identified risks. The analysis also considers trade-offs that may occur across social, economic, and environmental dimensions. For example, cobalt, a critical component in lithium-ion batteries, has significant social impacts due to production concentration in the Democratic Republic of the Congo. Shifting production to other regions may alleviate these risks but introduce new concerns about economic and environmental impacts.
Waste electrical and electronic equipment (WEEE) comprises a globally important waste stream due to the scarcity and value of the materials that it contains; annual generation of WEEE is increasing by 3–5% per annum. The effective management of WEEE will contribute critically to progress towards (1) realisation of the United Nations’ Sustainable Development Goals, (2) a circular economy, and (3) resource efficiency. This comprehensive review paper provides a critical and contemporary examination of the current global situation of WEEE management and discusses opportunities for enhancement. Trends in WEEE generation, WEEE-related policies and legislation are exemplified in detail. Four typical future WEEE management scenarios are identified, classified and outlined. The European Community is at the forefront of WEEE management, largely due to the WEEE Directive (Directive 2012/19/EU) which sets high collection and recycling targets for Member States. WEEE generation rates are increasing in Africa though collection and recycling rates are low. WEEE-related legislation coverage is increasing in Asia (notably China and India) and in Latin America. This review highlights emerging concerns, including: stockpiling of WEEE devices; reuse standards; device obsolescence; the Internet of Things, the potential for collecting space e-debris, and emerging trends in electrical and electronic consumer goods. Key areas of concern in regard to WEEE management are identified: the partial provision of formal systems for WEEE collection and treatment at global scale; further escalation of global WEEE generation (increased ownership, and acceleration of obsolescence and redundancy); and absence of regulation and its enforcement. Measures to improve WEEE management at global scale are recommended: incorporation of circular economy principles in EEE design and production, and WEEE management, including urban mining; extension of WEEE legislation and regulation, and improved enforcement thereof; harmonisation of key terms and definitions to permit consistency and meaning in WEEE management; and improvements to regulation and recognition of the informal WEEE management sector.
In this study, a method to evaluate the environmental effects of household refrigerators is newly developed in terms of life cycle climate performance (LCCP). The energy consumption model of the refrigerator is developed with three types of typical single evaporator refrigerators. The operation ratio of the evaporators, which is critical for calculating the energy consumption of dual evaporator refrigerators, is determined using experimental results of serial, bypass, and parallel-circuit cycle refrigerators. The LCCP results show that the system performance and equipment manufacturing emissions are dominant factors in lifetime CO2 emissions. Therefore, energy- and material-related factors, such as refrigerator cycle options, refrigerator material, insulation, and power sources, are primarily investigated. For cycle options, CO2 emissions can be reduced by 14.7% using a two-stage cycle. For condenser materials, CO2 emissions can be reduced by 2% to 2.5% using aluminum instead of steel. For insulation, the total emissions can be reduced by up to 7.7% by applying vacuum insulation panels on each side of the refrigerator. When 20% renewable energy is supplied, the total emissions are expected to be reduced by 13% in the baseline, 19.9% in the parallel-circuit cycle, and 26% in the two-stage cycle.
Although fluorescent lamps (FL) are extensively used worldwide, recycling rates in some countries are still low. If disposed of inappropriately and broken, FL can cause soil contamination. Hg toxicity in FL is extensively discussed in the literature; however, few studies address the other toxic metals present in the phosphorous powder of FL (PPFL). This paper presents a characterization of the environmental mobility with sequential extraction scheme (SES) of Cd, Cu, Hg, Mn, Ni, Pb, and Zn in PPFL, and modeling the potential risks to human health, in case of direct disposal in soils. An after thermal treatment waste was used for safety reasons. The SES method included five fractions, and the quantification was performed by flame atomic absorption spectrometry. Human health risk assessment (HHRA) was conducted using RISC4® software. The PPFL showed the following mobility sequence: Cu (85%) > Ni (81%) > Hg (80%) > Zn (77%) > Cd (75%) > Mn (6%) > Pb (2%), which suggests that Cu, Ni, Zn, and Cd, besides Hg, could be of environmental concern in terms of availability. HHRA showed the potential hazard of Cd, for both children and adults, in the hypothetical scenario of vegetable ingestion, considering vegetables grown in soils contaminated with FL waste. The thermal treatment does not completely remove Hg from the matrix, and the residual Hg still poses a risk to children. These results show that Hg and Cd can be hazardous to humans and reinforce the importance of the correct disposal and treatment of PPFL.
53 metallic elements from smartphones were investigated with regard to metal prices, metal production, and content in comparison to mined ores. The metal content of the 7.42 billion smartphone devices sold from 2012 to 2017 could theoretically maintain the global supply for 91 days for Ga, 73 days for Ta, 23 days for Pd, 14 days for Au, and 6 days for REE. The pure metal value of a single smartphone device for the investigated metals currently sums to 1.13 US from 2012 to 2017 with the highest value of 1.32 US $ in 2012. The Au content is low (16.83 mg per device), yet constitutes the highest value with a current share of approximately 72% of total value for all measured metals, followed by Pd (10%). Approximately 82% of total metal value can be recycled with current standard recycling methods for Au, Cu, Pd, Pt, which only comprise 6 wt% of the total device. The printed circuit board (pcb) contains 90% of the measured Au, 98% of Cu, 99% of Pd, 86% of In, and 93% of Ta. The Au, Pd, Cu, Pt, Ta, In, Ga contents in a smartphone pcb are significantly higher than the metal content in currently mined ores. Magnets contain 96% of the measured REE and 40% of the measured Ga, with higher concentrations than ores for REE and Ga. For Co and Ge, metal content in smartphones (w/o batteries) is lower than in ores.
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The export of e-waste from industrialized to developing countries has led to the formation of a large-scale informal e-waste recycling sector in Accra, Ghana. During recycling processes, workers are exposed to several hazardous substances, such as heavy metals. As a common component of e-waste, inorganic arsenic can be released during e-waste recycling processes. The aim of this study was to assess the exposure to inorganic arsenic species in e-waste workers compared to a control group. N = 84 e-waste workers and n = 94 control subjects were included in this analysis. Inorganic arsenic species were determined in urine samples using HPLC-ICP-MS. E-waste workers showed higher median concentrations of As(III), As(V), MMA, DMA and the sum of inorganic arsenic in comparison to the control group. More than 80% of the e-waste workers exceeded the acceptable concentration (14 μg/L), which was significantly higher in comparison to the control group (70%). The tolerable concentration (40 μg/L) was exceeded in 17.2% of the participants, meaning a statistically relevant risk of developing cancer due to arsenic exposure throughout their (working) life. In conclusion, the exposure to inorganic arsenic is not only a problem of informal e-waste recycling, but a major public health concern that needs further investigation.
Due to the lenient environmental policies in developing economies, mercury-containing wastes are partly produced as a result of the employment of mercury in manufacturing and consumer products. Worldwide, the presence of mercury as an impurity in several industrial processes leads to significant amounts of contaminated waste. The Minamata Convention on Mercury dictates that mercury-containing wastes should be handled in an environmentally sound way according to the Basel Convention Technical Guidelines. Nevertheless, the management policies differ a great deal from one country to another because only a few deploy or can afford to deploy the required technology and facilities. In general, elemental mercury and mercury-bearing wastes should be stabilized and solidified before they are disposed of or permanently stored in specially engineered landfills and facilities, respectively. Prior to physicochemical treatment and depending on mercury's concentration, the contaminated waste may be thermally or chemically processed to reduce mercury's content to an acceptable level. The suitability of the treated waste for final disposal is then assessed by the application of standard leaching tests whose capacity to evaluate its long-term behavior is rather questionable. This review critically discusses the main methods employed for the recovery of mercury and the treatment of contaminated waste by analyzing representative examples from the industry. Furthermore, it gives a complete overview of all relevant issues by presenting the sources of mercury-bearing wastes, explaining the problems associated with the operation of conventional discharging facilities and providing an insight of the disposal policies adopted in selected geographical regions.
The possibility of a pyrolysis process as a mean of recycling the residual plastic rich fraction (WEEE residue) derived from of a material recovery facility has been evaluated. The unknown product composition of WEEE residue has been supposed through coupled thermal – infrared analysis and ultimate analysis and resulted as PP 3 wt%, PBT 3 wt%, PVC 4 wt%, styrene-based polymers (principally ABS) 50 wt%, thermosetting resins (principally, epoxy/phenolic resins) 24 wt%, inorganic fraction (principally fiber glass) 16 wt%. DSC experiments showed that the overall energy, defined as the degradation heat, needed in order to completely degrade WEEE residue was about 4% of the exploitable energy of the input material. The effect of temperature and different zeolite catalysts were investigated, in particular in terms of yield and quality of the produced oils during the pyrolysis process. Produced oils were potentially exploitable as fuels and almost all catalysts improved their quality. The best performance was reached by NaUSY(5.7) with the second highest production of light oil and the greatest total monoaromatics yield, plus 12 wt% in comparison to thermal pyrolysis experiments. Furthermore, light oil produced by NaUSY(5.7) has one of the best LHV (36 MJ/kg) and no halogenated compounds were detected by GC–MS analysis. Char or pyrolytic gas combustion could supply the energy required for the thermal degradation of WEEE Residue.
African countries are among the prime destinations of electronic waste (e-waste) also called Waste of Electrical and Electronic Equipment (WEEE), and have been challenged with the management of its environmental and health impacts. This paper was carried out to understand the e-waste sector and policy responses in selected African countries. Data for the study were generated from sources; such as policy documents, legislations and literature. Findings show that the import of WEEE is on rising in Africa while landfill and incineration continued to be widely used handling approaches. Countries studied lack WEEE specific national policies and stringent policy instruments to enforce proper collection and recycling systems. Despite the start-ups in emerging recycling operations, a major gap is that informal e-waste actors dominate the e-waste chain from collection to material extraction and refurbish activities through rudimentary tools that cannot detect toxic elements. Tackling the problem demands integrated multi-actor interventions with multiple stakeholders to reduce WEEE inflow on one hand, and ramping up safe recycling capacity on the other hand.
Implications:
The article attempts to explain the electronic waste problem in African countries, the nature of existing policy responses and limitations, and ways forward to address policy gaps. Electronic waste is a global problem but with local impacts with the hazardous substances it contains. Because E-waste is still not well recognized health and environment threat, less attention is given for the problem especially in African countries making the uneducated youth more vulnerable to toxic elements. The epistemic community, hence, is supposed to write about it and develop knowledge so that evidences for policy decision making would grow. The focus is on Africa because the problem needs special attention. E-waste has been dumped in Africa for long time and people who work with such waste are mostly uneducated and vulnerable to toxic substances. This problem requires certain attention in the scholarly and policy community at the international level.
Lighting waste represents a significant source of rare earth elements (REE) and critical metals (CM), which are vital to low-carbon technologies. This research examines the environmental impacts of recovering REE (Yttrium and Europium) from linear fluorescent fixtures and CM (Gallium) from linear LED fixtures, as well as the implications of technology transition (e.g., from fluorescent to LED) and replacement decisions (i.e., extended use, modular replacement/retrofits, and full replacement) on waste management. An LCA is conducted by modeling 1 million lumen-hours of service from an 8 ft T8 linear fixture across 16 pathways representing multiple replacement and waste management options. The study finds that recovering REE and CM from lamp waste via hydrometallurgical methods generally result in more environmental impacts than the primary production of the recovered materials. Per kg recovered, the global warming impact is 74 kg and 3,687 kg CO2eq for REE and Ga, respectively. The high impacts for Ga recovery are due to Ga's low concentration (0.234 w/w%) in the LED waste. Intermediate results at the end of life stage show that recycling common metals (e.g., aluminum, copper, and sometimes steel) from fixtures can reduce or even completely offset the impacts of specialty metal recovery. Based on the end results, a mature technology like fluorescent fixtures can benefit from both extended use and modular product designs. The best strategy is to prioritize energy efficiency (e.g., by upgrading to new LED) and to choose full luminaire (lamps, electronics, and fixture) upgrades, which offer higher system efficacies, over retrofits (lamps and electronics only).
This paper addresses the determinants of metal recycling rates. The literature on recycling flows is scarce and does not directly address the issue of achieving a high recycling rate. In addition, extant literature has not quantified the recycling rate response to metal prices. Therefore, this paper explores factors that affect the recycling rate of different metals embodied in computers. We examine the effects of metal price, metal concentration in products, relative concentration ratio (i.e., primary vs. secondary supply), and embodied metal value on the recycling rate. Although the results reveal a significant effect of metal price on the recycling rate, the marginal response is low across different models (ordinary least squares, generalized linear model, fractional response model with endogenous regressor, and left-censored Tobit). This effect is not surprising and is in line with extant literature on recycling flows. Unfortunately, for most unrecycled metals, achieving a minimum embodied value is unlikely, as it would require a median price increase by one or two order of magnitude. In addition, it seems that the recycling rate is more elastic to other technical factors, such as the metal concentration in products or the relative concentration ratio. While the findings suggest important public policy implications, more data and interdisciplinary research are required to support these preliminary results.
Electronic waste (e-waste) is a rising global environmental and health inequity issue. Rapid and excessive manufacture and use of electronics is causing global e-waste buildup. While there is an opportunity to recover important and/or expensive resources (e.g., recovery of plastic, copper, gold, and platinum) via recycling, these discarded electronics contain many hazardous contaminants including heavy metals (e.g., lead, chromium, copper, mercury, nickel, zinc) and organic compounds (e.g., halogenated flame retardants). Each of these chemicals has been linked with adverse health effects, i.e., respiratory diseases, impairment of central nervous systems, carcinogenesis, and others. Because proper and safe e-waste recycling is expensive, informal recycling abounds, and illegal flows of e-waste (~60–90% of globally produced e-waste) occur from high- to low- and middle-income countries (LMICs). The informal repair and recycling of electronic devices in LMICs often occur without implementing proper protective measures for the workers or their environment. Commonly, e-waste repair/recycling workers are from poor and marginalized populations and in many cases, represent highly susceptible groups, such pregnant women and children. In this chapter, we discuss how the technological advancement of the electronics field has given rise to a worldwide problem.
This paper examines the creation and disposal of e-waste using an ecosystem framework that invites a critical examination of people (e-waste workers), business owners, consumers in communities, as well as broader policies, in order to identify the strengths and weaknesses in the transactional processes between these systems. The study is based in Pakistan, which is the 26th largest producer of e-waste, but is also the recipient of e-waste from other exporting nations. Survey results indicate local generation of electronic waste (extrapolated) is some 281 million in terms of equipment or 1790 kilo-tonnes (2018–2019). The paper illuminates the often hard to measure and less visible ‘upstream’ considerations, such as volumes and attitudes of consumers that drive buying and disposing decisions. For example, consumer preference for brand-new, low quality and cheaply priced equipment traps the community in a short-term gain and unrealised long-term pain cycle, as the negative effects are felt downstream in the environment and by workers involved in disposal. The study also identifies storage as a preferred option for obsolete items, usually because of a lack of suitable disposal options. The effect however is to effectively divert discarded equipment into landfill, with attendant costs to the environment or generate another pain cycle by exposing workers to toxic materials when processing e-waste using informal methods. Identifying transactional upstream processes in the ecosystem will enable responsive action to reduce and redirect consumer contributions to the burgeoning challenge presented by e-waste. The study also reveals high levels of consumer awareness and a willingness also to pay for e-waste recycling if a formal e-waste collection and recycling system was available.
Over the past few decades, electronic devices of all kinds, and especially consumer electronics, have evolved in function and composition, in parallel to increasing manufacture and use. There is great potential for recovering economic value and reducing environmental impact by recycling devices and extracting various elements. However, there are few studies that comprehensively identify the elemental content of electronic devices or electronic waste. In the present study, consumer electronics and components (hard drives, ethernet hubs, portable media players, printers, answering machines, mobile phones, Digital Versatile Disc (DVD) players, computer wiring, and printed circuit boards) and electronic waste (low-grade scrap from one commercial recycling facility) were analyzed for rare earth, precious and critical metals. The overall procedure included size reduction, microwave assisted digestion, and Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) analysis. Fifty-six elements were quantified or detected in these devices: 14 rare earth elements, six platinum group metals, 20 critical metals, and 16 other elements, including some precious metals. A single device could include a wide range of elements: 48 metals were quantified in the computer hard drives. The estimated economic value of the metals in each device ranged from 454 USD (hard drives). The variety of metals in electronic devices suggests that end-of-life management strategies should focus on recycling and recovery, which also decreases the overall environmental impacts of the devices, especially associated with mining and refining metals.
The rapidly growing fleet of electric vehicles contributes to transforming transport but presents challenges for managing spent lithium-ion batteries in the coming decades. Recently in Joule, Chen et al. reviewed the advantages and limitations of existing lithium-ion-battery recycling processes. To scale rapidly, recycling must be profitable, even for low-cobalt batteries.
This study presents a methodology designed for selecting, from an environmental point of view, the best end-of-life scenario for electric and electronic equipment which breaks before the end of its life span. To this end, the environmental impact of the life cycle of the equipment is evaluated for two different end-of-life scenarios: repair & reuse vs. replacement. As a case study, the proposed methodology is applied to a representative sample of nine categories of small household electric and electronic equipment (120 appliances). Repair & reuse scenarios consider the life span and the typical failures and repairs associated with each electric and electronic equipment category and the use of the repaired equipment until the remaining life span after its breakage. Replacement scenarios also consider the life span associated to each electric and electronic equipment category and the replacement of the broken equipment by an equivalent during the remaining life span after its breakage. The environmental impact obtained for both scenarios for each small household electric and electronic equipment category is compared in order to identify the best end-of-life scenario. To do so, the life cycle assessment methodology is applied, using CML and ReCiPe as midpoint- and endpoint-impact assessment methods, respectively. The results indicate that for all the analysed categories, the repair & reuse scenarios generally prove environmentally better than replacement scenarios, as Directive 2012/19/EU promotes. However, for some types of failure, e.g. those related to motors or printed circuit boards, if the failure occurs at the end of its life span, replacement is a better option than repair & reuse, since the environmental impact of the repair activities is not offset by the environmental benefits of extending the useful life until the end of the life span.