Waste from electronic equipment

Shredded circuit boards. Circuit boards are metal boards that hold computer chips, thermostats, batteries, and other electronic components. Circuit boards can be found in computers, televisions, radios, and other electronic equipment. When this equipment is thrown away, these boards can be removed and recycled. Whole circuit boards meet the definition of scrap metal, and are therefore exempt from hazardous waste regulation when recycled. On the other hand, some recycling processes involve shredding the board. Such shredded boards do not meet the exclusion for recycled scrap metal. In order to facilitate the recycling of such materials, U.S. EPA excluded recycled shredded circuit boards from the definition of solid waste, provided that they are stored in containers sufficient to prevent release to the environment, and are free of potentially dangerous components, such as mercury switches, mercury relays, nickel-cadmium batteries, and lithium batteries. 

To illustrate the concept of external (or damage) cost, we can first look at the emissions from Waste of Electric and Electronic Equipment (WEEE) to the air. The different points leading to the evaluation of emission s impact are the following [36] ... 

Isolating agent in small capacitors Cl < 42% Closed Waste from electric and electronic equipment/ household waste Possible in state-of-the-art sorting plants... 

Friege H (2012) Resource recovery from used electric and electronic equipment alternative options for resource conservation, Waste Mgt Res 30(9)... 

EEA - European Environmental Agency (2003) Waste from electric and electronic equipment -quantities, dangerous substances and treatment methods. http //eea.eioneLeuropa.eu/Public/irc/ eionet-circle/etc waste/library l=/working j>apers/weeepdf/ EN 1.0 a=d. Accessed 12 Nov 2010... 

Based on the values of Cpcdd/fs [46], Ccipahs [38], and CBfrs in e-waste, the annual mass emissions of selected PCDD/F and C1PAH congeners and BFRs from e-waste are estimated (Table 3). The lowest annual mass emission of PBDEs is about 82,207 tons/year, with 70,607 tons/year from importation and 11,600 tons/ year from domestic generation (Table 3). Nona- and deca-BDEs are the most important congeners as they are the major constituents of BRFs in electronic equipment [77]. In addition, the annual mass emissions of PBBs, TBBPA, and PBPs are also estimated with the same procedure (Table 3). Obviously, importation is responsible for the majority of annual mass emissions of e-waste-derived organic pollutants in China (Table 3). 

Convention on Control of Transboundary Movements of Hazardous Wastes and their Disposal and 69 ratified the ban on all kinds of hazardous waste export from wealthy OECD-countries to non-OECD countries, large amounts of waste electrical and electronic equipment (WEEE) are shipped overseas for recycling, the majority to China as reported by Brigden et al. [2] and Puckett et al. [3], lesser quantities to India and Western Africa reported by Kuper and Hojsik [4]. WEEE contains a variety of harmful substances like endocrine disruptors and persistent organic pollutants (POPs). Additionally, hazardous substances may be formed during informal recycling. This often practised informal treatment without proper equipment for metal extraction and labour safety heavily affects the environment and human health of workers and the inhabitants of whole stretches of land. 

The introduction of EU directives on Waste Electrical and Electronic Equipment and Reduction of Hazardous Substances has highlighted the need for precise and repeatable elemental analysis of heavy metals in the plastics production process. X-ray fluorescence (XRF) spectroscopy has emerged as the most economical and effective analytical tool for achieving this. A set of certified standards, known as TOXEL, is now available to facilitate XRF analyses in PE. Calibration with TOXEL standards is simplified by the fact that XRF is a multi-element technique. Therefore a single set of the new standards can be used to calibrate several heavy elements, covering concentrations from trace level to several hundred ppm. This case study is the analysis of heavy metals in PE using an Epsilon 5 XRF spectrometer. 

The German Environmental Ministry is reported to have attacked European proposals to ban substances such as specific flame retardants in forthcoming regulations for recycling electrical and electronic equipment. Initial proposals from the EU Commission on the disposal of waste electrical and electronic equipment, include a phaseout of PBDEs, despite preliminary findings under EU risk assessment that there is no need for risk reduction from the two types, decaBDE and octaBDE mainly used in such equipment. The Ministry is said to be concerned at the excessively prescriptive and restrictive system being proposed, and that substance restrictions should not be addressed in waste legislation, but should be based on life cycle risk assessments. 

Lymberidi, E. (2001). Towards Waste-Free Electrical and Electronic Equipment. The examples are cited from Tadatomo Suga, University of Tokyo, Good practice on the substitution of heavy metals in... 

R. Balart, L. Sanchez, J. L6pez, and A. Jimenez, Kinetic analysis of thermal degradation of recycled polycarbonate/acrylonitrile-butadi-ene-styrene mixtures from waste electric and electronic equipment,... 

P.A. Tarantili, A.N. Mitsakaki, and M.A. Petoussi, Processing and properties of engineering plastics recycled from waste electrical and electronic equipment (WEEE), Polym. Degrad. Stab., In Press, Accepted Manuscript, 2010. 

The environmental impact of waste disposal and of chemical use in Europe has led to three legislative actions that, in today s global economy, greatly affect flame-retardant use and research. These actions go by the acronyms of RoHS (Reduction of Hazardous Substances), WEEE (Waste Electrical and Electronic Equipment), and REACH (Registration, Evaluation, Authorisation, and Restriction of Chemical substances). These actions are discussed in detail in Chapter 22, but need to be mentioned here as they are clear examples of how changing regulations affect flame-retardant use, selection, and new fire-safety developments. The first one, RoHS, refers to how new items are manufactured, and specifically bans chemicals and elements of environmental and toxicological concern in Europe. One fall-out item of RoHS is the move from a lead-based solder on circuit... 

Schlummer, M., Maurer, A., et al (2006) Report recycling of flame-retarded plastics from waste electric and electronic equipment (WEEE). Waste Management and Research, 24(6) 573-583. 

Today important flows of plastics originate in mandatory recycling schemes, such as those imposed by take-back obligations on packaging, End-of life vehicles, or waste electric and electronic equipment (WEEE). For such materials, the drive for collection and recycling is not normally economic, but mandatory. In snch cases, there is often a dump fee, to be paid for farther processing a stream of waste plastics into recycled products. The value of such fees varies from some 50 /tonne for injection into blast fnmaces in the European Community to as much as 50-100 kYen ( 370-750 /tonne)... 

Waste from electrical and electronic equipment arises at the sorting plant, where the frame, the printed circuit board PCB, the cathode ray tube, etc. are separated for recycling. The remaining plastics fraction is in part flame-retarded, hence contains brominated and antimony compounds. The number of WEEE recycling plants is growing, so that the logistics are no longer a major problem. 

H. Boerrigter, Implementation of Thermal Processes for Feedstock Recycling from Plastic Waste of Electrical and Electronic Equipment, Netherlands Energy Research Foundation, Report ECN-C-00-114, 2000. 

On Earth, heat travels by conduction, convection, and radiation. However, conduction and natural convection are almost entirely nonexistent in the vacuum of space. Radiation is the primary method of heat transport in space. Space-based electronics that need to be kept cold are attached to radiators that face deep space and radiate excess heat into space. These electronics (i.e., space based phased-array-radar and laser systems) and radiators are thermally insulated from the rest of the spacecraft. Cooling is achieved through surface thermal radiation to deep space. Space-based electronics thermal management encompasses not only the removal of waste heat, but also the conservation of heat to provide a benign environment for the instruments and on-board electronic equipment. 

Leaching and electrolysis processes can be used for metal recovery from waste electrical and electronic equipment. Metals such as Ag, Au, Cu, Pb, Pd, Sn, are dissolved from shredded electronic scrap in an acidic aqueous chloride electrolyte by oxidizing them with aqueous dissolved chlorine species. In the electrochemical reactor, chlorine is generated at the anode for use as the oxidant in the leach reactor and the dissolved metals are deposited from the leach solution at the cathode. The very low concentrations of the precious metal ions require the use of porous electrodes with high specific surface areas and high mass transport rates to achieve economically adequate reactor productivities and space-time yields [72]. 

Other items such as medical devices and meters that use plastic parts are exempt from the RoHS requirement until such time as the EU sees fit to come up with specifications before including them. Waste Electrical and Electronic Equipment (WEEE) are defined as those requiring electricity or electromagnetic fields to operate them and most of the modern equipment contains plastics to some extent. 

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