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Achieving Resource Conservation in Electronic Waste Management: A Review of Options Available to Developing Countries



Innocent Chidi Nnorom, Oladele Osibanjo and Stanley Onyedikachi Nnorom
 
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ABSTRACT

Large quantities of waste electronic devices (e-waste) at their end-of-life, generated internally or imported illegally from developed countries, are currently being managed in the developing countries, through low-end means such as crude backyard recycling and disposal at unlined landfills or open dumps. The extension of the lifespan of electronic devices through reuse options such as repair, reconditioning and remanufacturing should be a priority in the management of electronic waste in developing countries considering the near absence of state-of-the-art recycling facilities in these countries. Life extension through product and component reuse is especially critical to electronic products because in recent years, electronics have increased in technological complexity, with new product innovations and ever shortening product life expectancy. For many products, environmentalists assume that reuse is environmentally beneficial because it replaces the manufacturing and purchase of new goods. However, on the contrary, manufacturers may oppose this type of reuse for the same reason. There is an urgent need to control the trans-boundary movement of electronic scrap especially to countries without established recycling facilities. Importations of secondhand electronics make such devices available to those who cannot afford new products. However, an international method of testing and certification is needed to ensure that exported secondhand devices are functional. Establishment of formal recycling facilities for e-waste in the developing countries will ensure resource reutilization with both economical and ecological gains. This study reviews options available in working towards eco-efficient management of e-waste in developing countries in the light of the present low-end management practices.

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  How to cite this article:

Innocent Chidi Nnorom, Oladele Osibanjo and Stanley Onyedikachi Nnorom, 2007. Achieving Resource Conservation in Electronic Waste Management: A Review of Options Available to Developing Countries. Journal of Applied Sciences, 7: 2918-2933.

DOI: 10.3923/jas.2007.2918.2933

URL: https://scialert.net/abstract/?doi=jas.2007.2918.2933

INTRODUCTION

Management of electronic waste has emerged as a global challenge since the last decade. The adoption of effective policy instruments and Extended Producer Responsibility (EPR) and the provision of reuse/recycling infrastructure have resulted in improved management practices in the developed countries. This is however not the case in developing countries. In most developing countries, an entire new economic sector has emerged and revolves around trading, repairing and material recovery (recycling) of electrical and electronic devices (e-waste) generated internally or imported illegally (Streicher-Porte et al., 2005; Liu et al., 2006; Hageluken, 2006a). Environmental concern about a product has gradually become a driving force for business activity in the form of extended producer responsibility and environmental labeling. Due to increased attention for producer responsibility and take-back of products, especially in developed countries, the environmental performance of end-of-life (EoL) processing of products as well as economic considerations have become important (Huisman and Stevels, 2002). While many of the social and environmental concerns of high-tech companies apply to both domestic and overseas operations, these issues are heightened in developing countries, where communities lack sufficient environmental regulation and enforcement, waste management infrastructure and protection of workers’ rights (Haugen, 2002). The problems specific to e-waste management in developing or industrializing countries have been identified and discussed (Widmer et al., 2005; Hicks et al., 2005; Streicher-Porte et al., 2005; Finlay, 2005; Liu et al., 2006; Osibanjo and Nnorom, 2007).

Concerns over the increasing generation of Waste Electrical and Electronic Equipment (WEEE) in the developed countries and the hazardous materials content of this waste group has led to a focus on extended producer responsibility in the form of the Waste Electrical and Electronic Equipment (WEEE) Directive in Europe and similar regulations/legislations in Asia (e.g., Japan, Taiwan) and North America aimed at product take-back for appropriate End-of-Life (EoL) management. The main objectives of these regulations include:

Reduction of waste arising from EoL electrical and electronic equipment (EEE).
Improvement and maximization of recycling, reuse and other forms of recovery for EoL EEE.
Minimization of the impact upon the environment from the treatment and disposal of EoL EEE.

Unfortunately, a large portion of European and North American electronic scrap is exported to Asia and Africa where e-scrap is mostly treated in backyard operations, using open sky incineration, cyanide leaching and simple smelters to recover mainly copper, gold and silver-with comparatively low yields-and discarding the rest (Hageluken, 2006a; BAN, 2002, 2005; Greenpeace, 2005; Schwarzer et al., 2005). Informal material recovery activities provide jobs and economic opportunities in the developing countries. This however poses risks to humans and the environment. In countries of these regions where the crude processes have not caught up, such as Nigeria, these waste items are disposed with municipal solid waste at open dumps, into surface water bodies and at unlined landfills, which are not monitored. Besides the tremendous adverse environmental and health effects in these regions, this also means a huge and mostly irreversible waste of resources. Hageluken (2006a) observed that it is particular irony if materials that had been collected e.g., in Europe under the WEEE Directive aiming to foster the environmentally sound reuse/recycling and to preserve resources finally ends up in such a recycling environment.

Eco-efficient management of WEEE requires the reuse of EoL EEE in the form of repair, reconditioning and remanufacturing and the recycling of un-reusable components. Reuse of electronic devices and parts are crucial in closing the loop for these items in the developing countries through extended product life and waste reduction. Formal recycling is required to check crude extraction processes, waste of scarce resources through disposal of WEEE with municipal solid waste and the attendant environmental pollution that results from such management practices. Recycling is the method of reuse most clearly established within public consciousness, where it is inextricably linked with the concept of waste reduction. While recycling reduces virgin material use, they do still require additional energy to be used to reform them into manufactured products. There is also the issue of recycling waste/slag management and air/soil pollution. Industries are also wary of reusing recycled materials/components because such items can have variable quality issues attached. Despite these challenges, recycling appears to be the best substitute in e-waste management in terms of technology and economic feasibility. However, state-of-the-art recycling facilities for e-scrap are rare in the developing countries. Hence reuse options should be considered prior to the establishment of formal recycling facilities in the developing countries.

Considering the near absence of effective recycling facilities for e-scrap in the developing countries, this paper reviews the relevance of value-added reuse of EoL products through repair, reconditioning and remanufacturing as tools in extending the life of electronic devices. These reuse options results in the reduction of the quantities of e-waste generated at least in the short-to-medium term.

E-WASTE MANAGEMENT IN DEVELOPING COUNTRIES

Definition and categories of WEEE: Electrical and electronic equipment cover a broad spectrum of products used by businesses and consumers. As defined in the WEEE directive (2002/96/EC), EEE includes equipment that are dependent on electric current or electromagnetic field in order to work properly and include equipment for generation, transfer and measurement of such currents and fields. It applies to products that are designed for use with a voltage rating not exceeding 1000 volts for alternating current and 1500 volts for direct current (Van Rossem, 2002; Yla-Mella et al., 2004; Widmer et al., 2005). Subcategories of these equipment are: large household appliances (refrigerators, washing machines, microwaves etc.), small household appliances (vacuum cleaners, toasters, coffee machines etc.), IT and Telecommunication equipment (computers, printers, copying machines, telephones, facsimiles etc), consumer equipment (radio sets, television sets, audio amplifiers, musical instruments etc.), lighting equipment (luminaries, discharge lamps, etc.), electrical and electronic tools (drills, saws, etc.), toys, medical equipment systems (radiotherapy equipment, nuclear medicine, cardiology, etc.), monitoring and control instruments (smoke detectors, heating regulators, etc.) and automatic dispensers (for hot drinks, solid products, etc.) (Milojkovic and Litovski, 2002). The division of WEEE into the above 10 categories of waste under EU WEEE Directive is shown in Table 1.

Table 1: Categories of WEEE according to the EU WEEE Directive
Image for - Achieving Resource Conservation in Electronic Waste Management: A Review of Options Available to Developing Countries
*: With the exception of large-scale stationary industrial tools, **: With the exception of all implanted and infected products, Source: Antrekowitsch et al. (2006)

EoL management activities in developing countries: A greater percentage of waste electrical and electronic devices collected for EoL management in developed countries are diverted to the developing countries (BAN, 2002, 2005; Greenpeace, 2005). In the developing countries there is a high level of reuse and repair activities for these imported devices. This returns some of the obsolete EEE to a second life. The unserviceable/ unusable EEE or modules are usually disassembled (incomplete disassembly) for component retrieval for use in repair activities. E-waste in the developing countries are usually managed through low-end means such as open burning, disposal with municipal waste at unlined landfills and into surface water bodies and through crude backyard informal recycling activities. The environmental implications of the informal crude material recovery activities taking place in some Asian countries are enormous and have been documented by Greenpeace, Basel Action Network (BAN) and other Non-Governmental Organizations (NGOs). These activities have not yet caught-up in Africa, except in South Africa where there is recycling activities for EoL WEEE.

There is fear that if and when the crude material recovery technologies, currently wrecking havoc in some Asian countries, are introduced into Africa, the environmental pollution from such activities in Asia may be a child’s play. The developed countries, especially European countries and Japan have state-of-the-art recycling facilities for WEEE and are even importing selected components of WEEE (especially, printed wiring board) for material extraction.

The reasons behind the present low-end management of WEEE and/or existence of ineffective informal WEEE processing sector in the developing countries include:

The unwillingness of consumers to handout their EoL goods. This is because consumers view their waste as a resources and income-generating opportunity.
There is a general reluctance to pay for waste recycling and disposal services, particularly when consumers can make money by selling their old and broken appliances.
There is a lack of awareness among consumers, collectors and recyclers of the potential hazards of WEEE.
Lack of funds and investment to finance improvements in e-scrap recycling.
Absence of infrastructure for the recycling or appropriate management of e-scrap following the principles of sustainable development.
Absence or ineffective take back programs for EoL WEEE.
Absence of legislation dealing specifically with e-waste or ineffective /lax implementation of existing regulations on the trans-boundary movement of e-waste (Osibanjo and Nnorom, 2007; Hicks et al., 2005; Finlay, 2005).

ISSUES IN THE MANAGEMENT OF EoL ELECTRONICS

Producer responsibility and sustainable development: The escalating growth in consumer waste in recent years has started to threaten the environment. Product recovery is mainly driven by the escalating deterioration of the environment and aims to minimize the amount of waste sent to landfills by recovering materials and parts from old or outdated products by means of recycling and reuse.

The need for sound management of EoL consumer electronic products arises from the global goal of achieving sustainable development. Product remanufacturing, parts reuse and materials recycling are advocated for obtaining both resource conservation and waste reduction. Sustainable development in turn gave birth to many areas of research in academia, introduced new concepts in industrial design and even resulted in legislation (e.g., WEEE and RoHS Directives) which help to implement the concept of sustainable development (Campbell and Hasan, 2003). The European Commission has highlighted the environmental impacts associated with EEE by preparing two complimentary directives: the Waste from Electrical and Electronic (WEEE) Directive and the Restriction of Hazardous Substances (RoHS) Directive. The WEEE Directive aims at increasing the rates of recovery or recycling and hence minimizing the amount of EEE being put on landfills at EoL. The WEEE Directive sets precise recovery rates and recycling targets and focuses on an increased reuse of components, materials and substances. Such new concept for reuse affects economical, environmental and social aspects in a positive way. Besides take-back and safety aspects, the WEEE Directive will regulate re-use and recovery rates. The rates of re-use and recycling of components, parts and substances will range from 50 to 75% and the recovery rates will even range from 70% up to 80% depending on the kind of EEE (Herrmann et al., 2002). The RoHS Directive prescribes that the use of certain substances be prohibited in most EEE applications. These substances include: lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls (PBB) and polybrominated diphenyl ethers (PBDE). The implementation of the WEEE Directive has raised awareness of issues surrounding the manufacture, use and disposal of EEE and together with other initiatives to address general waste and encourage recycling will contribute to meeting sustainability goals (Darby and Obara, 2005). The European ICT industry has established processes to successfully complying with the requirements of the WEEE and RoHS Directives and there are indications that existing business initiatives are trying to extend these practices to the rest of the world (IST, 2005).

Presently, the key area of on-going intensive research is design-for-EoL (DfEoL), which has emerged as a key component of design for environment. This targets special EoL management techniques such as,

Design for product-life-extension through upgrade or refurbishment.
Design for component recovery and reuse through disassembly.
Design for recyclability.
Design for use of secondary components and materials.
Design for identification, separation and proper handling of toxic and hazardous materials (Rifer and Stitzhal, 2002; Campbell and Hasan, 2003).

Due to increased attention for producer responsibility and take-back of products, the environmental performance of EoL processing of products as well as economic considerations have become important. EoL processing of consumer goods can serve several goals. These include:

Reduction of materials going to landfill; minimizing landfill volume.
Recycling of materials in order to keep maximum economical and environmental value.
Reduction of emission of environmentally relevant substances; including leaching from landfill sites and incineration slag etc. (Huisman et al., 2002).

In 1999, Norway became the first country in Europe to pass legislation setting up a free take-back system for all discarded electrical and electrical products. The economic burden of this take back system or extended producer responsibility is placed on the producer/ importer. Consumer and professionals/companies can deliver discarded electrical and electronic products to the retailer, who is required to accept them free of charge and pass them on through the system for treatment, recycling and/or disposal (Ronningen, 2002).

Essentially, producer responsibility is an indirect European Commission legislative-based policy designed to ensure that market pressures are harnessed to achieve environmental protection through the management of EoL EEE. It is hoped that producer responsibility will also allow all WEEE to be diverted away from municipal landfill by ensuring that appropriate EoL management structure are set in place and that reduction of waste at source will be facilitated through better design.

Extended producer responsibility makes producers responsible for their EoL products so that they have an incentive to design their products for dismantling, with recyclable materials and reusable components. Economics may not encourage EoL products to be seen as assets, so legislation (such as the EU WEEE and RoHS Directives) is needed to force take-back.

Reverse logistics: An important concern in EoL management for electronic products is to connect the equipment owners with potential buyers who may be interested in their EoL items, whether for reuse, component retrieval or material recovery.

Reverse logistics is the movement of the goods from a consumer towards a producer in a channel of distribution. Reverse logistics is the process of planning, implementing and controlling the efficient, cost effective flow of raw materials, in-process inventory, finished goods and related information from the point of consumption to the point of origin for the purpose of recapturing value or proper disposal. A reverse logistics defines a supply chain that is redesigned to efficiently manage the flow of products or parts destined for remanufacturing, recycling, or disposal and to effectively utilize resources (Ravi et al., 2005; Hu et al., 2002).

With the obsolescence rates of EEE on the rise, an important question that remains to be answered is what can be done to these EoL EEE both from economical and environmental points of view. Due to shortening of product life cycles for products like consumer electronics, the recovery of value from these consumer goods, after use, is becoming a necessity. Several options are available in the management of WEEE. These include temporary storage, reuse of products and components, recycling, landfilling and incineration. If offsetting of the increasing demand of landfills is to be done, enhanced efforts for EoL product reuse and/or recovery (recycling) are needed, which directly requires the reverse logistics activities. Reverse logistics provides many opportunities to reuse and create value out of this nearly omnipresent asset (Ravi et al., 2005).

Before recovery or other appropriate EoL management for WEEE can take place, the products must be collected from the consumers a reversal of the logistics system that distributed the products to the consumers. Products take-back is of great importance and is faced with challenges considering that it requires the participation of several subjects generally not connected among themselves. These challenges are enormous in societies where no stringent regulations and environmental protection tradition exists.

Reverse logistics systems available in the management of WEEE include curbside pickup, the consumer taking recyclables to a central collection point or returning them to the retailer as part of a deposit/refund system (Lave et al., 1999).

Management options for EoL consumer goods: Products go out of use for essentially two reasons: functional obsolescence (they physically fail and need repair) or fashion obsolescence (they loose their appeal due to new products appearing in the market with different/additional features). Planned obsolescence is one way in which capitalist markets generate demand for new sales (King et al., 2004).

Recovering products at their EoL from consumers diverts wastes disposed in landfills and results in recapturing asset value from the recovered products. The five common options for material recovery from EoL products are: repair, refurbish, recycle, cannibalization and remanufacturing.

Repair and reuse-this return used products in working order.
Refurbishing this brings the quality of returned products up to a specified level by disassembly to the modular level, inspection and replacement of broken modules. Refurbishing could also involve technology upgrading by replacing outdated modules or components with technologically superior ones.
Remanufacturing this brings used products up to quality standards that are as rigorous as those for new products by complete disassembly down to the component level and extensive inspection and replacement of broken/outdated parts.
Cannibalization this aims at recovering a relatively small number of reusable parts and modules from used products, to be used in any of the three operations mentioned earlier.
Recycling the purpose of which is to reuse materials from used products and parts by vigorous separation processes and reusing them in the production of original or other products (Parlikad and McFarlane, 2004; Parlikad et al., 2003).

In addition, parts and materials that could not be recovered by any of the above five operations will be disposed appropriately. More than one of these options may be chosen for any particular product, i.e., a certain proportion of components maybe reused and the rest may be recycled, incinerated for energy recovery or disposed. Although reuse is completely different from recycling, reuse can have significant environmental and economic benefits (Thomas, 2003a). Product reuse is the preferred option in the end-of-life management of electrical and electronic devices.

If the rebuilding of the product is not extensive, i.e., if few parts are to be replaced, either of the terms reconditioning or refurbishing is used. Reconditioning/ refurbishing is also used when the product is only remanufactured to its original specifications. Lindahl et al. (2006) observed that remanufacturing is becoming the generic term for the process of restoring discarded products to useful life. The EoL management option adopted is usually determined after considering several factors. Factors such as cost, labor, availability, returning flow volume and optimal disassembly level determine which recovery process is feasible (Ritchey et al., 2001).

Recycling is currently the most common form of recovery in e-waste management. Recycling consists of disassembling a product to material level, sorting the material and transforming them into a reusable form.

Factors driving material recovery: Product recovery activity has gained increasing importance because it is considered a way of reducing waste. The main driving force for end-of-life product recovery includes: market restrictions, recapturing hidden economic value and government legislation (Ritchey et al., 2001; Gungor and Gupta, 1999; Lim et al., 2005).

Market restrictions refer to after-market sales. The Original Equipment Manufacturer (OEM) may want to inhibit other firms from reclaiming its products and reselling them under the OEMs name. To accomplish this, the OEM must reclaim the products, thus restricting the after-market for third party firms.
Recovery due to market restrictions currently occurs only on a small scale. Recapturing hidden economic value fails to provide adequate profit motivation at current landfill disposal rates in the developed countries. Firms that recover EoL products for this purpose in an attempt to resell the materials or parts a second time rarely see enough profit to justify the costs of the recovering process.
Government regulation, for example, the EU WEEE Directive, is typically the driving force behind product recovery by companies. There are environmental regulations enforced by the government in several countries (based on the polluter-pays-principle) charging manufacturers with responsibility for the entire product life cycle, including their safe disposal.

The customers expectation of green products is another factor to consider. It has been observed that customers are showing preference for environmentally conscious firms and products and are willing to pay for a better environment (Lim et al., 2005). It is well known that recovering WEEE for reuse and recycling conserves resources and feedstock that supply steel, glass, plastic and precious metals. Such recycling also avoids air and water pollution as well as greenhouse gas emissions associated with materials production and manufacturing. For these reasons, the number of regulatory and voluntary initiatives aiming to increase EoL reuse and recycling is increasing around the world (Hula et al., 2003).

RE-USE OPTION FOR EoL ELECTRONICS

Extended producer responsibility has motivated OEMs research towards resource use limitation, pollution prevention and waste avoidance through ecological (green) design, reuse, remanufacturing and efficient recycling (Schwarzer et al., 2005). There are two common ways of electronic products recovery, namely: Remanufacturing and demanufacturing. Remanufacturing focuses on rebuilding the product whereas demanufacturing focuses on disassembling products and recovering value wherever practicable (Lim et al., 2005). Product recovery includes collection, disassembly, cleaning, sorting, repairing bad components, reconditioning, testing, reassembling and testing. Recovered parts/products are used in repairs, remanufacturing of other products and components (Nakashima, 2006). The decision of how to treat an obsolete equipment or WEEE and which recycling route is most appropriate should be made ecologically and economically as best as is possible (Herrmann et al., 2002). The hierarchy for waste treatment recommended by the EU WEEE and other regulations so as to improve closing the products loop is: first avoid waste; if not avoidable, re-use of components, parts and materials is preferred; then material recovery or at least energy recovery has to take place before finally, disposition or landfilling may take place (Herrmann et al., 2002). Under the WEEE Directive, specific definitions apply to reuse, recovery and recycling.

Reuse means any operation by which WEEE or components thereof are used for the same purpose for which they were conceived.
Recycling means the reprocessing in a production process of the waste material for the original purpose or for the other purposes but excluding energy recovery.
Recovery means (physical) recycling of materials plus the recovery of energy as heat e.g., after feeding organic parts of waste into an incineration process (Hageluken, 2006b).

The main goal of product reuse is to extend the product life of the equipment, thus diverting it from landfills. Reuse options such as repair, reconditioning and remanufacturing requires product dismantling/ disassemble.

EoL product disassembly: Several decision variables must be considered when determining the maximum environmental benefit that can be achieved for a given economic cost when a product reaches its EoL. These variables include the extent of disassembly, the disassembly sequence (if disassembly occurs) and the EoL fate for removed components as well as the product remainder not disassembled (Hula et al., 2003). Virtually all the EoL options available for the management of WEEE require some form of disassembly. Disassembly involves the removal of components and specific materials from the products. Das and Yedlarajiah (2002) visualized disassembly as a multi-step process or plan, intended to unlock the inherent value of a product. Disassembly process is strongly influenced by the demand on modules that consists of multiple parts.

Disassembly is a labor intensive task and the cost of disassembly is proportional to the effort that must be expended to remove components. The optimal disassembly decision balances the cost of disassembling a product against the value of components removed, environmental liabilities and the residual material value in the product (Sodhi and Reimer, 2001).

In general, current demanufacturing facilities manually disassemble or dismantle products. Demanufacturing presents several problems for automated processing: product identification, a wide variety of possible products even within a particular product type, unknown configurations due to consumer alterations, jammed components, missing components and damaged components. Kuren (2002) observed that automated demanufacturing approach requires generalized design information for product families in order to maximize success of the system.

Disassembly can be partial (product not fully disassembled) or complete (product fully disassembled). In addition, disassembly can be destructive (focusing on material rather than component recovery), or non-destructive (focusing on components rather than materials recovery). Since the process of disassembly is complex as well as labor-intensive, it tends to be very expensive (Nakashima, 2006; Parlikad and McFarlane, 2004).

Extensive research has been conducted at optimizing disassembly (Gungor and Gupta, 1999; Lambert, 2002; Hula et al., 2003; Spengler et al., 2002). The most attractive research on disassembly process is in the use of robots. However, robotic disassembly is cost prohibitive (Chiodo et al., 2002). The automated assembly of electronic equipment is well advanced. Unfortunately, full (semi) application of automation disassembly for recycling of electronic equipment is full of frustration (Cui and Forssberg, 2003). Only a few pilot projects for automated disassembly are operational and majority of disassembly of EEE are carried out manually. Disassembled components and modules can be used by the OEMs, third-party remanufacturers, business entities within the reuse/service/maintenance cycle and the material reclaimers (recyclers) (Kumar et al., 2005).

Disassembly plays a crucial role in achieving sound management of WEEE. Disassembly is not equivalent with inverse assembly (complete disassembly). In contrast with assembly that has to be carried out completely, disassembly, because of both technical and economic constraints, cannot usually be performed to the full extent. Lambert (2002) observed that complete disassembly is not possible because of irreversible connections and economic constraints resulting from disassembly costs that are disproportional to the revenues that can be obtained by the recovery of the involved parts.

Das and Yedlarajiah (2002) observed that several valuable revenue streams can be generated from product disassembly. These include:

Separate the product into parts or subassemblies so as to increase the material yield of the downstream shredding/reclamation process.
Reclaim parts with high reuse values.
Reclaim and safely dispose of parts with hazardous content (e.g., batteries, mercury switches).
Reclaim parts with high calorific value for downstream incineration and possible energy recovery (e.g., plastics).
Destruction of parts and components to prevent unauthorized parts resales and therefore protecting intellectual property.
Reclaim parts for direct entry into material reuse channels (e.g., glass parts).

Repair: Repairing a product is the process of rectifying a number of given faults with a product and returning it to useful service. It also includes the elimination of secondary damage such as worn components or cosmetic damage (i.e., dents) (Barker and King, 2006). The most logical approach to closing the loop on products is simply to repair and extend the products life. Repairing is simply the correction of specified faults in a product. Generally, the quality of the repaired products is inferior to those of remanufactured and reconditioned alternatives. The consumer decision during the use phase of a product whether to repair, pass on or throw items away accordingly affect product life spans and thus the rate of waste generation.

Repairing a product appears to be a simple concept. However its practice is low especially in developed countries and little research has been undertaken to understand this closed loop option (King et al., 2004). Repairing restores only damaged or faulty components and do not provide similar guarantees as new products. The high rate of repair of EEE in the developing countries extends the lifespan of electronic products thereby reducing the quantity of WEEE generated in the short-term.

Maintenance is required to preserve a product in a workable condition during use and proper maintenance will minimize the decline of product performance during its life. Usage issues that are controlled by the consumer during use (or indirectly by the designer) include: i) product loading and usage cycles and ii) product maintenance and servicing. The actual loading experienced during use of a product will have a significant effect on the product condition, which determines the amount of work required to utilize the product or its components in a new use (reuse) cycle (Kumar et al., 2005).

Recondition: Reconditioning involves less work content than remanufacturing, but more than that of repairing. This is because reconditioning usually requires the rebuilding of major components to a working condition that is generally expected to be inferior to that of the original model. All major components that have failed or that are on the point of failure will be rebuilt or replaced, even where the customer has not reported or noticed faults in the components (King et al., 2004). While this produces a product restored to full working order, the product is clearly second-hand (Barker and King, 2006).

The fact that a reconditioned product is clearly not new and thus not offering the latest functionality or aesthetic styling of new product means that it has the same market acceptance issues to products that have been repaired (King et al., 2004). However greater product performance is guaranteed. Reconditioning offers a suitable product to people on benefits and low income families who would otherwise find such goods unaffordable. Reconditioning is not the same as remanufacturing; remanufacturing occurs when the product is discarded as an end-of-life product. For example, reconditioning of a refrigerator might include recharging the refrigerant, polishing the exteriors/interiors or fixing defects in the refrigerator. However, remanufacturing may include the reconditioning step, replacing damaged components, followed by rigorous testing as if the refrigerator was a new product (Kumar et al., 2005). Another difference is that in remanufacturing, the specifications of the old product may be upgraded to bring it close to the specifications of a new product. For example, the old ozone depleting refrigerant could be replaced with a more ozone-friendlier alternative.

Remanufacturing: Remanufacturing is the reuse of components and assemblies of returned products to produce new or similar products of equal or superior quality and reliability. It encompasses collection, sorting, disassembly, cleaning, replacing and/or repairing defective components, testing, reassembling and inspecting the product in order to return it to “like-new” condition (Gungor and Gupta, 1999; Barker and King, 2006). Remanufacturing reduces virgin material cost and utilizes less energy than recycling, thereby increasing its profit potential as a recovery process. Another benefit of remanufacturing is that it enables manufacturers to discover weaknesses in the product structure and materials thus identifying areas needing improvement. One major obstacle in this scenario is that not all products are remanufacturable (Ritchey et al., 2001). Remanufacturing as a reuse option has been extensively studied (Nasr and Thurston, 2006; Lindahl et al., 2006; Lopez-Ontiveros et al., 2003; Barker and King, 2006; King et al., 2004; King and Burgess, 2005; Ritchey et al., 2001).

Two approaches to executing remanufacturing process were identified by Ritchey et al. (2001).

First, the returned products are disassembled to part level; the parts tested, necessary upgrades performed and reassembled into a new product with the same parts as before.
The second approach is to disassemble the product to part level, test all parts and place those that pass the test into the production assembly line.

The specific remanufacturing steps to be undertaken depend on market requirements i.e., the quality of the incoming product or subassembly or component and the consumer expectation. The economic challenges of remanufactured products and the consumer attitude toward remanufactured products where discussed by Michaud and Llerena, (2006).

Remanufacturing is often thought of as a highly complex recovery system, giving rise to the popularity of recycling. There are numerous variables contributing to the feasibility of remanufacturing;

Return flow.
Collection costs.
Inventory costs.
Disassembly cost.
Technological feasibility, labor cost.
Cost of testing.

Each of these costs plays a role in determining the profitability of remanufacturing. A review of these variables was presented by Ritchey et al. (2001). Actually any product may be remanufactured if it can be disassembled and cleaned, if its components can be repaired or replaced so that the original function and performance level are kept, if there is enough demand for the product and if the whole process is economically viable (Michaud and Llerena, 2006). It has been observed that the labor cost to remanufacture an EoL product must be less than or equal to the cost of manufacturing a new item in order for remanufacturing to be feasible (Ritchey et al., 2001).

Remanufactured products possess an added value as they are brought to OEMs performance specifications at least from the customers perspective and are presumed equivalent to new products. Remanufacturing of products is also an information feedback source for the OEMs, as the customers views especially with respect to reliability and durability are obtained.

Image for - Achieving Resource Conservation in Electronic Waste Management: A Review of Options Available to Developing Countries
Fig. 1: The hierarchy of secondary market production processes (Ijomah, 2002)

Figure 1 shows the three operations of repair, reconditioning and remanufacturing on a hierarchy based on the work content that they typically require. Also presented in the diagram are the performance that should be obtained from the operations and the value of the warranty that they normally carry (King et al., 2004). Compared to repair and reconditioning, remanufacturing involves the greatest degree of work content and as result its products have superior quality and reliability. This is because remanufacturing requires the total dismantling of the product and the restoration and replacement of its components (King et al., 2004). Moreover, these activities are carried out at the OEM accredited centres. The cost of remanufacturing a product depends on the state of the product. Remanufacturing of cellular phones and computers are briefly reviewed.

Cellular phone: It has been observed that in order to meet required recovery rates (set by the EU WEEE Directive), manufacturers must decide whether they will pursue material recycling processes or remanufacturing processes to enable the reuse of phones or components (Seligar, 2003). While the required recycling rates can hardly be met economically by material recycling of cellular phones of current design, remanufacturing of cellular phones is developing into a reasonable alternative. In fact, third party remanufacturers have identified the collection and treatment as a competitive business field and are already making profit from selling remanufactured cellular phones in emerging and less developed markets. With an annual sales volume of over 3 million remanufactured phones in 2003, Seligar (2003) noted that the US third party remanufacturers have proven that cellular phone remanufacturing is a competitive business field. The challenges and principle processes necessary for cellular phone remanufacturing were also discussed by Seligar (2003).

Computers: Many multinational companies are involved in the refurbishment of used EEE and the reuse of recovered components. Milojkovic and Litovski (2002) observed that IBM is actively involved in these activities, with about twenty foundries established by the company where used computers are collected, dismantled and recovered components sorted and refreshed (refurbished) for reuse. Within the period 1994-1997, IBM recycled 30,000t of computer products. These results in economical and ecological gains, as financial gains are made and environmental pollution mitigated. Within the company, $50 million was saved from use of refurbished components, $10 million gained from sales of used components to retailers around the world and $2 million from sale of materials extracted after recycling (Milojkovic and Litovski, 2002).

Recycling Materials recoverable from WEEE: The composition of e-scrap depends strongly on the type and the age of the scrap. For example, scrap from IT and telecommunication systems contain a higher amount of precious metals than scrap from household appliances. In older devices, the content of noble metals is higher but also the content of hazardous substances is higher than in newer devices (Antrekowitsch et al., 2006). E-waste contains considerable quantities of valuable materials such as precious metals. Early generation PCS used to contain up to 4 g of gold each; however this has decreased to about 1 g today (Widmer et al., 2005).

Electronic scrap is composed of a ratio of approximately 40:30:30 of metal, plastics and refractory oxides, respectively. The typical metal scrap consists of copper (20%), iron (8%), tin (4%), nickel (2%), lead (2%), zinc (1%), silver (0.2%), gold (0.1%) and palladium (0.005%). Polyethylene, polypropylene, polyesters, polycarbonates and phenol formaldehyde are typical plastic components. Sodhi and Reimer (2001) observed that as at mid 1999, one ton of electronic waste, processed efficiently, could yield up to US $9193.46. The main source of revenue from electronic scrap is from gold. Even though gold constitutes only 0.1% of the material content of e-scrap, more than 85% of revenue derivable from e-scrap is from it (Sodhi and Reimer, 2001).

Recycling options: Recycling consists of disassembling a product to material level, sorting the materials and transforming them into a reusable form. However, it has been observed that recycling does not retrieve the highest economic value for a product at its EoL (Ritchey et al., 2001). Recycling, in spite of the positive effects, might add to environmental pollution if waste is not properly pre-treated and disposed and if the recycling facilities are not state-of-the-art facilities equipped with pollution abatement equipment.

Campbell and Hasan (2003) classified computer recycling business activities into two categories: disassembly companies and processing companies. Disassembly companies are companies that collect computers from the end users and depending on the functionality of the equipment, 1) resell them on “as is” basis, or 2) disassemble and reconfigure them to resell system and components. Processing companies are a step downstream of disassembly companies and have the capabilities to process disassembled parts to eventually recover raw materials (e.g., precious metal recovery). Additionally, processing companies, depending on the scope of businesses may perform some or all of the steps performed by the disassembly companies. Depending on EoL recycling policy adopted, recycling companies can generate revenue from selling refurbished appliances, components and recycled raw materials, as well as charging fees to producers or customers (Hicks et al., 2005). Antrekowitsch et al. (2006) observed that the existing processes for recycling of electronic scrap are not optimized in an economical and ecological way. The following methods for the treatment of electronic scrap were reviewed by Antrekowitsch et al. (2006):

Mechanical separation.
Thermal treatment.
Hydrometallurgical treatment.
Electrochemical treatment.
Biotechnology

Antrekowitsch et al. (2006) however observed that currently, there is no existing plant which uses biotechnology for the recycling of e-scrap.

Recycling of WEEE can also be broadly divided into three major steps:

Disassembly (dismantling: Selective disassembly, targeting on singling out hazardous or valuable components. This is an indispensable process.
Upgrading: Using mechanical/physical processing and/or mechanical processing to upgrade desirable materials, that is, preparing materials for processing.
Refining: In the last stage, recovered materials return to their life cycle (Cui and Forssberg, 2003).

Table 2: High value extractable metals in e-scrap streams compared with a typical copper ore (%)
Image for - Achieving Resource Conservation in Electronic Waste Management: A Review of Options Available to Developing Countries
Source: Antrekowitsch et al. (2006)

One of the main objectives of the EU initiative is to increase the recycling of WEEE. In general, recycling preserves resources and disposal capacities, in particular landfill. In order to get material from the electronic waste, it should be recycled. This requires that the materials obtained from the recycling process have all the characteristics of the virgin material and the price of these materials should be low enough to make them compete favorably with the virgin materials (Milojkovic and Litovski, 2002). Comparison of selected e-scrap items with typical copper ore (Table 2) indicates that more value can be obtained from e-scrap (Antrekowitsch et al., 2006).

Details of activities carried out in mechanical and bulk recycling of electronic wastes have been presented (Sodhi and Reimer, 2001; Cui and Forssberg, 2003; Zhang et al., 1998). Mechanical processes such as screening, shape separation, magnetic separation, Eddy current separation, electrostatic separation and jigging were reviewed by Cui and Forssberg (2003). Zhang et al. (1998) studied the application of High Force Eddy current separator in aluminium recovery from electronic scrap. A state-of-the-art smelter and refinery process for e-scrap has a major impact on recycling efficiency, in terms of elements and value that are recovered as well as in terms of overall environmental performance (Hageluken, 2006a, b). Many electrical appliances are recycled because they have high value for their scrap metal content. However, the recycling of freezers, air conditioners and refrigerators is not very profitable because these products require special handling of the refrigerants or foam-blowing agents (Kumar et al., 2005).

Obstacles to effective recycling: The useful life of consumer electronic devices is relatively short and decreases as a result of rapid changes in equipment features and capabilities (Kang and Schoenung, 2004). Management of e-waste presents challenges because of the physical nature of these devices especially size and composition variations and potential heterogeneity within the devices and between devices (Yla-Mella et al., 2004; Cui and Forssberg, 2003).

Thomas, (2003b) observed that:
“The obstacles to product recycling and reuse are widely recognized. Products are widely dispersed among consumers, so finding and collecting products for recycling or appropriate EoL management is difficult. Each consumer and business is faced with a complex problem of trying to optimize the management of many types of products. Moreover, there are many different models of the same types of products, each requiring different EoL procedures”.

Challenges faced by WEEE management are not only consequences of growing quantities of waste but also the complexity of WEEE: it is one of the most complex waste streams because of the wide variety of products from mechanical devices to highly integrated systems and accelerating technological innovations (Yla-Mella et al., 2004). As a result of the variety of products models, size changes, compatibility issues etc. the recovery of WEEE is very challenging (Kumar et al., 2005). There has also been high rate/level of miniaturization of EEE, high rate of introduction of new models and the short working life of the products.

There are many models of each type of EEE and each may have different components and different requirements for dismantlement and recycling. There are, for example, over 1800 different models of cell phones registered with the European Telecommunication Standards Institute, made by more than 50 manufacturers (Saars et al., 2004).

Computers and other EEE are designed with little regard for downstream impacts and ease of recycling. This may be the reason why there is little economical recycling of WEEE taking place in some rich developed countries. Consequently, these countries resort to exporting their e-waste to developing countries. Obtaining access to the valuable materials that are contained in e-waste- especially metals like copper or gold- is difficult because they are bound up in plastics and mixed with other contaminants that make it expensive to separate (Roman and Puckett, 2002).

Factors influencing electrical and electronics recycling has been discussed by Herrmann et al. (2002). The decision of which material recycling route to choose is influenced from several aspects which interact also among each other:

Which material or elements are contained?
How is their connection or combination?
How are the materials or elements recoverable, i.e., are they recoverable elementarily or even as a compound material such as plastics?
Which recycling routes exist or are available?

ISSUES

Green innovations: Green design is the key technology to realize manufacturing industries sustainable development and it is gaining more and more attention. Green design refers to the consideration of every design alternative, environmental impact and resource utilization along the life cycle of a product from material choice to the components and parts disassembly and material recycling (among others) at the beginning of the products design. This will enable designers compare alternatives and optimize the design. Fisher et al. (2005) observed that:

With new technology leading to new and better products for consumers and industry comes new challenges associated with the life cycle management of these products. At each life cycle stage; acquisition of material and energy feedstock, product manufacture, use, maintenance, repair and final disposal of waste, consideration must be given to achieving an acceptable balance between environmental impacts, economic growth and social benefits. In other words, products must be examined from a sustainability perspective.

Research at assessing and managing the environmental impacts of electronics gave rise to the field of Green Electronics. The major area of research and activities include:

Design for environment.
Recycling processes and systems.
Eco-labeling.
Disassembly.
Greening supply chain.
Life cycle assessment (Williams, 2005).

An increasing awareness of the effects of technological advances on the environment has spurred research into environmentally conscious or green engineering (Nakashima, 2006; Kuren, 2002). Environmental Conscious Manufacturing (ECM) is mainly driven by the escalating deterioration of the environment. It has become an obligation to the environment and to the society. Product recovery should be considered in the design and managing of the manufacturing systems (Nakashima, 2006).

International conferences and workshops such as the Comprehensive Approach for the Recycling and Eco-Efficiency of Electronics (CARE electronics/CARE INNOVATION) and the International Symposium on Electronics and the Environment (ISEE) have been in the forefront at discussing environmental issues, process innovations, advances in manufacturing and product recycling and design for environment (DfE) especially as they relate to the EEE design and production.

Outlook: Today in industrialized countries EoL information and communication technology (ICT) equipment is processed separately from other waste streams, given its material composition and appliance size. Efforts to manage electronic waste in these countries are being driven in large part by legislation developed in the European Union.

To effectively articulate and implement appropriate EoL management for WEEE, there must be an effective collection or take-back for the obsolete/discarded EEE items. The implementation of an effective take-back for WEEE will be challenging and difficult in countries where there are no stringent regulations existing for environmental protection traditions on solid waste management (and WEEE in particular) and the existent of formal recycling facilities.

In most developing countries without recycling facilities for WEEE, effective collection strategy for WEEE is still necessary for reasons that include:

The collected WEEE can be dismantled /disassembled for component reuse and disposal of toxic components at designated sites.
The collected WEEE can be stored in warehouses until appropriate EoL management issues are resolved. This temporary storage will control the indiscriminate disposal of these items with municipal solid waste and the open burning of such waste material within inhabited areas.
Large stockpiles of WEEE are a prerequisite in the economics of WEEE recycling. Large quantities of WEEE can be used to lure recyclers to invest in developing countries or transfer the technology through subsidiaries or franchise. These collected items can also be exported as recyclables to the OEM recycling facility abroad, their business affiliates and/or to third party recyclers.
Even where low-end management such as landfilling and incineration are the only available options, these activities can be carried out using appropriate technology at selected sites. This though not the preferred options may be better than the open burning of such waste material within inhabited areas and/or disposal at unlined landfills that are not monitored.

If product design permits and there is an adequate process for return of used products (reverse logistics), there can be a strong business model in product remanufacturing. This is because the energy and virgin raw materials used in producing a remanufactured product are substantially less than that used in producing a new product (Nasr and Thurston, 2006). Given a readily available market that has so adapted to secondhand electronics (which are often purchased without testing for functionality), product reuse through reconditioning and remanufacturing will play a huge role in solving the e-waste problem in developing countries especially when the OEMs warranty is issued.

Remanufacturing retains more of the energy associated with the original conversion of raw materials to finished products (Nasr and Thurston, 2006). Remanufacturing differs from repairing since it results in a product with the same performance and expected life span as the original product. By contrast repairing restores only damaged or faulty components and do not provide similar guarantees as new products. Remanufacturing is also different from recycling. Remanufactured products and components keep their original function while recycling only deals with the raw materials of used products which are then used in the manufacturing of products with different functions (Michaud and Llerena, 2006). From an environmental point of view, remanufacturing seems to be a sound way to achieve functional products. The remanufacturing process results in a functional product, while recycling only provides materials (Lindahl et al., 2006). However, the main challenges in most remanufacturing activities is the handling of uncertainty regarding time, quality and place of product returns that affect collection, testing, disassembly, reassembly and the warehousing of spare parts (Kernbaum et al., 2006). A summary of reuse and recovery options available for end-of-life electronics is shown in Table 3.

Recommendations: In most developing countries, including Nigeria, there is an unorganized sector actively involved in the refurbishing and upgrading of used PCS and other EEE. Repair and reuse activities generally decreases the demand for new EEE, creates opportunity for the acquisition of EEE by those who cannot afford new equipment, creates jobs in an informal second-hand market and decreases the amount of EEE reaching their EoL at least in the short-to-medium time scale.

Table 3: Reuse and recovery options for end-of-life consumer goods
Image for - Achieving Resource Conservation in Electronic Waste Management: A Review of Options Available to Developing Countries
Source: Krikke et al. (2003)

For effective remanufacturing of EoL electronics, there is need to incorporate Design for Reuse (DfR) at the product design stage. Design for reuse entails the design and production of consumer goods that are easier to reprocess at their EoL. This will ensure effective dismantling, thereby making for reuse of components and module during reconditioning and remanufacturing. Such a design will also ensure production of less waste items and also less toxic wastes at the EoL. Engineering remanufacturable products brings important issues related to product design, production planning and reverse logistics.

The residual value of a product depends on various quality parameters such as the age, the functional condition (working or not working), physical condition, functional age (as a measure of obsoleteness), remaining useful life etc. The values of these parameters, which define the current status of the product often, have to be determined through inspection or estimated from knowledge gathered from experience (Parlikad and McFarlane, 2004).

For the effective management of EoL EEE and reduction in WEEE generation and the attendant environmental and health consequences especially in the developing countries, we recommend:

Establishing remanufacturing centers by the OEMs.
Training local manpower to ensure adequate reverse flow of components/modules.
Establishing frameworks and the necessary logistics for the take-back of EEE and components for reuse and recycling.
Creating a readily available market for the disassembled components- for local consumption and export.
Establishing state-of-the-art incineration or landfill facilities for the hazardous components recovered from the disassembly.
Introducing formal recycling facilities.

The above may not be achieved without the collaboration of the OEMs. The global manufacturers of electronic appliances should own up and take responsibility for their EoL products according to the EPR principle incorporated in the EU WEEE Directive irrespective of where the EoL activities are taking place. They should practice extended producer responsibility and assume liability associated with the final fate of their products.

CONCLUSIONS

Considering the hazardous materials composition of obsolete EEE, there is need for the effective management of EoL WEEE. This requires an effective take-back framework for EoL EEE, their reuse and recycling and the management of the toxic/residual materials in a sustainable manner. Lave et al. (1999) noted that recycling is good only if environmental discharges and the resources used to collect, sort and recycle a material are less than the environmental discharges and resources needed to provide an equivalent virgin material plus the resources needed to dispose of the material safely.

Remanufacturing is the most suitable option for product reuse. However, the issues of products take-back (reverse logistics), disassembly, remanufacturing cost, technical feasibility and the customers view of remanufacture products as not new are barriers to effective implementation of remanufacturing as an effective tool in managing electronic waste.

Considering the prevailing economic realities, most developing countries may not easily acquire the technical know how for remanufacturing and eco-efficient material recovery from e-scrap. As such trade in second-hand electronics should be strictly restricted to products with confirmed functionality (Osibanjo and Nnorom, 2007). On achieving this, the prior consent of the receiving country should still be sought before shipment. There is an urgent need to educate the consumer and the public in general in the developing countries on the hazardous contents of electronics and the dangers of inappropriate disposal options. Collaboration between the OEMs, government, consumers, NGOs and end-of-use processors (recyclers) from within and outside the developing countries is required in order to improve on the present EoL management practices for WEEE in the developing countries.

REFERENCES
1:  Antrekowitsch, H., M. Potesser, W. Spruzina and F. Prior, 2006. Metallurgical Recycling of Electronic Scrap. In: The Minerals, Howard, S.M. (Eds). Metals and Materials Society, Warrendale, PA., USA., pp: 889-908.

2:  BAN, 2002. Exporting harm: The high tech trashing of Asia. The Basel Action Network and Silicon Valley Toxics Coalition.

3:  BAN, 2005. The digital dump: Exporting Re-use and Abuse to Africa. Basel Action Network. October, 24.

4:  Barker, S. and A. King, 2006. The development of a remanufacturing design platform model (RDPM): Applying design platform principles to extended remanufacturing practice into new industrial sectors. Proceedings of the LCE 13th CIRP International Conference on Life Cycle Engineering, May 31-June 1, 2006, Wales, Sydney, pp: 399-404.

5:  Campbell, M.I. and A. Hasan, 2003. Design evaluation method for the disassembly of electronic equipment. Proceeding of International Conference on Engineering Des. ICED Stockholm.

6:  Chiodo, J.D., N. Jones, E.H. Billett and D.J. Harrison, 2002. Shape memory alloy acuators for active disassembly using smart materials of consumer electronic products. Mater. Design, 23: 471-478.
Direct Link  |  

7:  Cui, J. and E. Forssberg, 2003. Mechanical recycling of waste electrical and electronic equipment: A review. J. Hazard. Mater., B99: 243-263.
Direct Link  |  

8:  Darby, L. and L. Obara, 2005. Household recycling behavior and attitude towards the disposal of small electrical and electronic equipment. Resour. Conserv. Recycl., 44: 17-35.
Direct Link  |  

9:  Das, S. and D. Yedlarajiah, 2002. An integer programming model for prescribing material recovery strategies. Proceeding of the International Symposium on Electronics and the Environment, May 6-9, 2002, San Francisco, CA., USA., pp: 118-122.

10:  Finlay, A., 2005. E-waste challenges in developing countries: South Africa case study. APC Issue Papers. Association for Progressive Communications. http://www.apc.org/en/pubs/issue/environment/africa/e-waste-challenges-developing-countries-south-afri.

11:  Fisher, M.M., F.E. Mark, T. Kingsbury, J. Vehlow and T. Yamawaki, 2005. Energy recovery in the sustainable recycling of plastic from end-of-life electrical and electronic products. Proceedings of the International Symposium on Electronics and the Environment, May 16-19, 2005, New Orleans, LA., USA., pp: 83-92.

12:  Brigden, K., I. Labanska, D. Sanyillo and M. Allsopp, 2005. Recycling of electronic waste in China and India: Workplace and environmental contamination. Greenpeace Report, Greenpeace International. pp: 56

13:  Gungor, A. and S.M. Gupta, 1999. Issues in environmentally conscious manufacturing: A survey. Comput. Ind. Eng., 36: 811-853.
Direct Link  |  

14:  Hageluken, C., 2006. Recycling of electronic scrap at umicore=s integrated metal smelter and refinery. Proceedings of the European Metallurgical Conference EMC 2005, September 18-21, 2006, Dresden, pp: 152-161.

15:  Hageluken, C., 2006. Improving metal returns and eco-efficiency in electronic recycling a holistic approach to interface optimization between pre-processing and integrated metal smelting and refining. Proceedings of the International Symposium on Electronics and the Environment, May 8-11, 2006, San Francisco, pp: 218-223.

16:  Haugen, H.M., 2002. Economic forces driving the electronic industry towards sustainability. In: Proceedings of the 2002 Care Innovation Conference, Vienna.

17:  Herrmann, C., P. Eyerer and J. Gediga, 2002. Economic and ecological material index of end of life and design of electronic products. Proceeding of the International Symposium on Electronics and the Environment, May 6-9, 2002, San Francisco, CA., USA., pp: 11-16.

18:  Hicks, C., R. Dietmar and M. Eugster, 2005. The recycling and disposal of electronic waste in China-legislative and market response. Environ. Impact Assess. Rev., 25: 459-471.
Direct Link  |  

19:  Hu, T.L., J.B. Sheu and K.H. Huang, 2002. A reverse logistics cost minimization model for the treatment of hazardous wastes. Trans. Res. Part E, 38: 457-473.
Direct Link  |  

20:  Huisman, J. and A. Stevels, 2002. Eco-efficiency of take-back and recycling. Application in stakeholder discussions. Proceedings of the 2002 Care Innovation Conference, Vienna.

21:  Huisman, J., A.B. Stevels and I. Stobbe, 2002. Eco-efficiency considerations on the end-of-life of consumer electronic products. Proceedings of the International Symposium on Electronics and the Environment, May 6-9, 2002, San Francisco, CA., USA., pp: 59-64.

22:  Hula, A., K. Jalali, K. Hamza, S.J. Skerlos and K. Saitou, 2003. Multi-criteria decision-making for optimization of product disassembly under multi situations. Environ. Sci. Technol., 37: 5303-5313.

23:  Ijomah, W.L., 2002. A model-based definition of the generic remanufacturing business process. Ph.D. Thesis. University of Plymouth.

24:  IST, 2005. Assessing opportunities for ICT to contribute to sustainable development. Information Society Technologies and European Commission Information Society and Media. December, pp: 15-16.

25:  Kang, H.Y. and J.M. Schoenung, 2004. Used consumer electronics: A comparative analysis of material recycling technologies. Proceedings of the IEEE International Symposium on Electronics and the Environment, Phoenix, AZ.

26:  Kernbaum, S., C. Franke and G. Seligar, 2006. Flat screen monitor disassembly and testing for remanufacturing. Proceedings of the LCE, 13th CIRP International Conference in Life Cycle Engineering, May 31-June 2, 2006, Belgium, pp: 435-440.

27:  King, A.M., W. Ijomah and C.A. McMahon, 2004. Reducing end-of-life waste: Repair, recondition, remanufacture or recycle? Proceedings of the ASME Conference, Sept. 20-20, Salt Lake City, USA.

28:  King, A.M. and S.C. Burgess, 2005. The development of a strategic response to the directive on waste electrical and electronic equipment. J. Eng. Manuf., 219: 623-631.
Direct Link  |  

29:  Krikke, H.R., H.M. LeBlanc and S. Van-de-Velde, 2003. Creating value from returns. CenTER Applied Research Working Paper No. 2003-02. January 2007, pp: 7. http://www.inomics.com/cgi/repec?handle=RePEc:dgr:kubcar:20032.

30:  Kumar, V., D.J. Bee, P.S. Shirodkar, S. Tumkor, B.P. Bettig and J.W. Sutherland, 2005. Towards sustainable product and material flow cycles: Identifying barriers to achieving product multi-use and zero waste. Proceedings of the IMECE ASME International Mechanical Engineering Congress and Exposition, November 5-11, 2005, Orlando, Florida, USA., pp: 1-11.

31:  Kuren, M.B.V., 2002. Automated demanufacturing studies in detecting and destroying threaded connections for processing electronic waste. Proceeding of the International Symposium on Electronics and the Environment, May 6-9, 2002, San Francisco, CA., USA., pp: 299-305.

32:  Lambert, A.J.D., 2002. Determining optimum disassembly sequence in electronic equipment. Comput. Ind. Eng., 43: 553-575.
Direct Link  |  

33:  Lave, L.B., C.T. Hendrickson, N.M. Conway-Schempf and F.C. McMicheal, 1999. Municipal solid waste recycling issues. J. Environ. Eng., 125: 944-949.
Direct Link  |  

34:  Lim, G.H., R.D. Kusumastuti and R. Piplani, 2005. Designing a reverse supply chain network for product refurbishment. Proceedings of the International Conference on Simulation and Modeling.

35:  Lindahl, M., E. Sundin and J. Ostin, 2006. Environmental issues within the remanufacturing industry. Proceedings of the 13th CIRP International Conference on Life Cycle Engineering, May 31-June 2, 2006, Linkoping University, Sweden, pp: 447-452.

36:  Liu, X., M. Tanaka and Y. Matsui, 2006. Electrical and electronic waste management in China: Progress and the barrier to overcome. Waste Mgt. Res., 24: 92-101.

37:  Lopez-Ontiveros, M.A., P. Zwolinski and D. Brissand, 2003. Profile of products for the creation of remanufacturable products during the conceptual design phase. Proceedings of the CIRP Seminar on Life Cycle Engineering, Copenhagen, Denmark.

38:  Michaud, C. and D. Llerena, 2006. An economic perspective on life cycle engineering. Proceedings of the 13th CIRP International Conference on Life Cycle Engineering, May 31-June 2, 2006, IEEE Xplore, pp: 543-548.

39:  Milojkovic, J.B. and V.B. Litovski, 2002. Eco-design in electronics-the state of the art. Facta Univ. Working Living Environ. Prot., 2: 87-100.
Direct Link  |  

40:  Nakashima, K., 2006. Markov analysis of an environmental conscious manufacturing system with stochastic variability. Int. J. Global Logistics Supply Chain Manage., 1: 17-24.

41:  Nasr, N. and M. Thurston, 2006. Remanufacturing: A key enabler to sustainable product systems. Proceedings of the 13th CIRP International Conference on Life Cycle Engineering, May 31-June 2, 2006, Sydney, Australia, pp: 15-18.

42:  Osibanjo, O. and I.C. Nnorom, 2007. The challenge of electronic waste (e-waste) management in developing countries. Waste Manage. Res., 25: 489-501.
CrossRef  |  Direct Link  |  

43:  Parlikad, A.K., D. McFarlane E. Fleisch and S. Gross, 2003. The role of product identity in end-of-life decision making. AUTO-ID CENTRE. White Paper. July 1.

44:  Parlikad, A.K. and D. McFarlane, 2004. Investigating the role of product information in end-of-life decision making. Proceedings of the 11th IFAC Symposium on Information Control Problems in Manufacturing, April 5-7, 2004, Brazil, pp: 1-6.

45:  Ravi, V., R. Shanker and M.K. Tiwari, 2005. Analyzing alternatives in reverse logistics for end-of-life computers: ANP and balanced scorecard approach. Comput. Ind. Eng., 48: 327-356.
Direct Link  |  

46:  Rifer, W. and D. Stitzhal, 2002. Electronic product design for end-of-life management: A policy perspective. Proceedings of the International Symposium on Electronics and the Environment, May 6-9, 2002, San Francisco, CA., USA., pp: 284-289.

47:  Ritchey, J., F. Mahmoodi, M. Frascatore and A. Zander, 2001. Assessing the technical and economic feasibility of remanufacturing: Environmental issues. Proceedings of the 12th Annual Conference of the Production and Operations Management Society, Mar. 30-Apr. 2, Orlando, Fl.

48:  Roman, L.S. and J. Puckett, 2002. E-scrap exportation: Challenges and considerations. Proceeding of the International Symposium on Electronics and the Environment, May 6-9, 2002, San Francisco, CA., USA., pp: 79-84.

49:  Ronningen, B., 2002. Regulations and market forces combined to success. Proceedings of the International Symposium on Electronics and the Environment, May 6-9, 2002, San Francisco, CA., USA., pp: 85-88.

50:  Schwarzer, S., A. De Bono, G. Guiliani, S. Kliser and P. Peduzzi, 2005. E-waste: The hidden side of IT equipment's manufacturing and use. United Nations Environment Programme Geneva. http://ewasteguide.info/e_waste_the_hidden_s.

51:  Seligar, G., 2003. Contribution to efficient cellular phone remanufacturing. Proceedings of the CIRP Seminar on Life Cycle Engineering, May 22-23, 2003, Copenhagen, Denmark, pp: 1-16.

52:  Sodhi, M.S. and B. Reimer, 2001. Model for recycling electronics end-of-life products. OR Spektrum, 23: 97-115.
Direct Link  |  

53:  Spengler, T., G. Walther, J. Hesselbach and M. Ohlendorf, 2002. Product assessment and recycling data analysis as precondition for efficient weee recycling. Proceedings of the Going Green Care Innovation, November 25-28, 2002, Vienna, pp: 1-7.

54:  Streicher-Porte, M., R. Widmer, A. Jain H.P. Bader, R. Scheidegger and S. Kytzia, 2005. Key drivers of the e-waste recycling systems: Assessing and modeling e-waste processing in the informal sector in Delhi. Environ. Impact Assess. Rev., 25: 472-491.
Direct Link  |  

55:  Thomas, V.M., 2003. Demand and dematerialization impacts of second-hand markets: Reuse or more use? J. Ind. Ecol., 7: 65-78.
Direct Link  |  

56:  Thomas, V.M., 2003. Product self-management: Evolution in recycling and reuse. Environ. Sci. Technol., 37: 5297-5302.
Direct Link  |  

57:  Van-Rossem, C., 2002. Environmental product information flow-communication of environmental data to facilitate improvements in the ICT sector. Report No. 3102. The International Institute for Industrial and Environmental Economics (IIIEE). Lunds University and Swedish National Chemical Inspectorate (KEMI).

58:  Widmer, R., H. Oswald-Krapf, A. Sinha-Khetriwal, D. Sinha-Khetriwalb, M. Scnellmann and H. Boni, 2005. Global perspectives on the e-waste. Environ. Impact Assess. Rev., 25: 436-458.
Direct Link  |  

59:  Williams, E., 2005. International activities on E-waste and guidelines for future work. Proceedings of the 3rd Workshop on Materials Cycles and Waste Management in Asia, December 14-15, 2004, Tsukuba, Japan, pp: 1-10.

60:  Yla-Mella, Y., E. Pongracz and R.L. Keiski, 2004. Recovery of Waste Electrical and Electronic Equipment (WEEE) in Finland. Proceedings of the Waste Minimization and Resource use Optimization Conference, June 10, 2004, Oulu, Finland, pp: 83-92.

61:  Zhang, S., E. Forssberg, B. Arvidson and W. Moss, 1998. Aluminium recovery from electronic scrap by High-Force eddy-current separators. Resour. Conserv. Recycl., 23: 225-241.
Direct Link  |  

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