Eco-Efficiency of Take-Back and Recycling,
a Comprehensive Approach
Jaco Huisman
andAb L. N. Stevels
Abstract—A key question in setting up take-back systems for discarded consumer electronics is how much environmental im-provement can be realized per amount of money invested. With the efficiency concept developed, the environmental and eco-nomic performance of single products within various end-of-life scenarios can be quantified as well as the contribution of individual materials and material fractions to this performance. Also anal-ysis the effectiveness and efficiency of optimization and changes in the take-back system like, glass recycling and plastic recycling, and Design for End-of-Life activities is determined. Moreover, the envi-ronmental effectiveness and cost-efficiency effects of the European Waste of Electrical and Electronic Equipment (WEEE) Directive is reviewed. Based on the eco-efficiency analyses, an implementa-tion roadmap for this legislaimplementa-tion is proposed in order to further improve environmental performance on one hand and to minimize costs on the other hand.
Index Terms—Eco-efficiency, electronics, end-of-life, waste policy strategies.
I. INTRODUCTION
T
HE Quotes for environmentally WEighted RecyclabiliTY and Eco-Efficiency (QWERTY/EE) approach developed at the Technical University of Delft (TU Delft) is a comprehen-sive and quantified eco-efficiency methodology. It is supporting ongoing discussions about responsibilities, organization and fi-nancing of the take-back systems in practice with quantified en-vironmental and economic quantifications [5]. For this purpose, extensive environmental data sets were developed [1], [5]–[8] and in addition, substantial technical and cost data have been gathered. The resulting eco-efficiency calculations are presented in two-dimensional graphs in which one axis displays economic costs and revenues, the other displays environmental burden and gain. This overall method is abbreviated as QWERTY/EE.The graphs as presented in the examples section in this paper illustrate the eco-efficiency effects of changes in take-back system operation for consumer electronic products, like ap-plying new technologies, change of collection infrastructures, the consequences for the various stakeholders involved, and how return behavior can influence system performance. In
Manuscript received January 31, 2005; revised August 25, 2005. This work was supported in part by the Dutch Ministry of Environment, Division Non Hazardous Waste (VROM), The Stichting Nederlandse Verwijdering Metalektro Producten (NVMP, Dutch take-back system), and Philips Consumer Electronics, Environmental Competence Centre (PCE-ECC).
J. Huisman is with the Delft University of Technology, 2628 CE Delft, The Netherlands (e-mail: J.Huisman@io.tudelft.nl).
A. L. N. Stevels is with the Delft University of Technology and Philips Con-sumer Electronics, Environmental Competence Centre, Eindhoven, The Nether-lands (e-mail: ab.stevels@philips.com).
Digital Object Identifier 10.1109/TEPM.2006.874970
the QWERTY/EE approach, products to be considered are classified as plastic, metal, precious metal, and glass-domi-nated products and show that improvement avenues in design, technology, and policies and take-back system operation are different for these four categories.
As will be demonstrated in the next two sections, the fol-lowing aspects can be addressed:
1) performance of single products in other end-of-life options, like incineration and landfill as well as the effects of plastic recycling or glass recycling;
2) contribution of individual materials and material fractions in this environmental and economic performance, hence generating improvement avenues in design, policy, tech-nology and system organization;
3) the contributions and influence of single stakeholders (re-cyclers, system operators, governments and secondary ma-terial processors) or individual stages in the end-of-life chain (collection, pre-treatment, etc.) to the total end-of-life chain can be determined;
4) the consequences for system organization (this includes vi-sualization of the influence of logistics, economies of scale due to collective versus individual systems, the effect of changing collection rates, etc.);
5) optimization of the relation between recyclers and sec-ondary material processors and final waste processors by quantifying the answer for: Which materials should end up in which fractions to be treated by which secondary mate-rial processors?
One of the important application fields of the approach is to provide detailed insights on how to come to more eco-efficient waste policy strategies in general [5] and for implementation of the European Waste of Electric and Electronic Equipment (WEEE) Directive by EU member states in particular as well as to draw lessons for other area’s in the world where legis-lation and/ or take-back system are proposed (the US, China, Japan, etc.). In general, there are five legislative instruments to improve environmental performance of end-of-life products by prescribing:
1) weight-based recycling and recovery targets (obviously present in WEEE);
2) restrictions on hazardous substances (RoHS Directive [2]); 3) treatment rules for recyclers (WEEE Annex II);
4) minimum collection amounts (4 kg per inhabitant per year);
Fig. 1. Calculating QWERTY values.
the use of specific hazardous materials and specific treatment rules for recyclers with mandatory selective removal operations for certain components like printed wiring boards (PWBs), elec-trolytic capacitors, liquid crystal display (LCD) screens, and plastics containing brominated flame retardants).1In the WEEE Directive, there is limited or no attention on the minimum col-lection amount strategy (the prescribed minimum of 4 kg per inhabitant per year is relatively easy to obtain) and also not on the strategy of prescribing in more detail the outlets of recy-cling operations. This last strategy means prescribing minimum processing destinations and technical standards for treatment of the fractions created by shredding and separation and/ or dis-mantling (for instance a minimum amount of secondary CRT glass back to CRT production). The Restriction on the use of Hazardous Substance (RoHS) Directive,1which addresses the strategy of restricting hazardous substances is out of the scope of the present article.
II. QWERTY
The QWERTY are based on the comprehensive environ-mental and economic modeling of the end-of-life chain. The general idea is based on environmental and economic quantifi-cation of three values as displayed in Fig. 1 [7] and subsequent calculation of the distances between these three outcomes
A. Minimum Environmental Impact and Minimum Costs
These two values (environmental and economic) are corsponding with the theoretical scenario of all materials being re-covered completely assumingly without any environmental im-pact or economic costs of end-of-life treatment steps. As such, they are representing the environmental and economic substi-tution values of primary materials that is the value for newly extracted and produced materials. Usually, both are negative (avoided environmental impacts of new extraction and revenues being negative costs). The values are strictly theoretical: in prac-tice there will always appear (environmental) costs connected to separation of materials, energy consumption, and transport in order to realize recovery of materials.
1Commission of the European Communities, Directive 2002/96/EC of the
Eu-ropean Parliament and of the Council on Waste Electrical and Electronic Equip-ment (WEEE). Official J. European Union. Brussels, Belgium, Feb. 13, 2003.
Fig. 2. Weight versus environmental weight for a cellular phone.
B. Maximum Environmental Impact and Maximum Costs
These two values are defined as the theoretical scenario of every material ending up in the worst possible (realistic) end-of-life route, including the environmental burden plus (environmental) costs of pretreatment: collection, transport, disassembly and shredding, and separation into fractions. The “realistic” end-of-life scenarios under consideration are con-trolled and unconcon-trolled landfill, incineration with or without energy recovery, and all subsequent treatment steps for material fractions, like copper, ferro, and aluminum smelting, glass oven, and plastic recycler. Also, this theoretical value cannot easily be exceeded: only under extreme disposal conditions, which are normally forbidden by law.
C. Actual Environmental Impacts and Costs
These values are based on the actual environmental and eco-nomic performance of the end-of-life scenario under consid-eration and are compared with the two boundary conditions above and finally expressed as percentages. These actual values are obtained by tracking the behavior of all materials over all end-of-life routes and by taking into account all costs and envi-ronmental effects connected to this as discussed in Section IV.
In Fig. 2, an example is given on applying the QWERTY method on the material composition of an average 2001 cel-lular phone [10]. It demonstrates the large difference between thinking in terms of weight-based recycling targets and the ac-tual environmental equivalent when a product consist of rela-tively low amounts of precious metals, but high connected en-vironmental impacts of recovering these materials and thus pre-venting new highly environmentally burdening extraction.
All detailed backgrounds and formulas to calculate QW-ERTY values can be found in [5], [7]. The environmental values can be calculated with different life cycle assessment (LCA) methods or even individual impacts categories like for instance greenhouse effect to display the influence of different environmental perspectives. As a default method however, the Eco-Indicator’99 method is used [3].
III. ECO-EFFICIENCY
dis-Fig. 3. Example of two-dimensional eco-efficiency graphs.
played as vectors in Fig. 3. Such scenarios or options describe certain changes in end-of-life treatment or applying certain tech-nological improvements like separate collection and treatment of cellular phones for instance. In order to achieve higher eco-ef-ficiencies, improvement options should lead to a change from the reference or starting point into the direction of the upper right part of Fig. 3 (point A). However, options with a direction towards the lower-left part of Fig. 3 should be avoided (higher costs and higher environmental impacts), because from the point of reference a lower eco-efficiency is realized (point B). The other two points C and D are leading to the same environmental improvement but also to higher costs compared to the reference point. When point C and D are to be compared, one could say that in general direction C is more eco-efficient than direction D, because the same environmental improvement is realized with lower integral costs.
Application of the eco-efficiency method to analyze take-back and recycling includes two important steps:
Step 1 is application of a “vector approach” as sketched above. This means that in the first instance, the four quadrants are selected. When for example separate collection and treat-ment of cellular phones is applied and the resulting vector is directed to the first quadrant (for instance point A) of Fig. 1, a so-called “positive eco-efficiency” is realized, compared to the original situation (reference point) without plastic recycling. The opposite counts for the third quadrant. Options and direc-tions is this case should be avoided from both an environmental as an economic point of view.
Step 2 includes calculation of environmental gain over costs ratios and ranking of the “quotient” for the second and fourth quadrant. This is when an environmental improvement is realized and financial investments are needed to obtain this (or the opposite). In the case of multiple options appearing in the fourth quadrant, the “quotient approach” can be applied to determine how much (absolute) environmental improvement (mPts) is realized per amount of money invested (Euros). (In the second quadrant, higher revenues or lower costs are ob-tained against higher environmental impacts.) When a certain option leading to a vector in the second quadrant is reversed, the result will appear in the fourth quadrant and can be treated similarly (by using the opposite point of the vector as reference or starting point).
IV. INGREDIENTS ANDASSUMPTIONS
The ingredients for the environmental part of the calculations are as follows.
1) Detailed product compositions and amounts of all relevant substances, like heavy metals and precious metals, must be known. Many data are derived from [12] and from envi-ronmental benchmarks of products from Philips Consumer Electronics [11].
2) Furthermore, shredding and separation behavior and disas-sembly characteristics of products must be known[5]. 3) Accurate Life Cycle Inventories for metals are obtained
from TU Delft, Department of Applied Earth Sciences [14], [15].
4) Technical data on further treatment of certain fractions, like acceptance criteria, input requirements, and recoveries at aluminum, ferro, and copper smelters are available from [6] and from individual contacts with German and Dutch recyclers and waste processors.
5) Collection data, transport distances, and energy consump-tion numbers are gathered for the Dutch E&EE take-back system.
6) Landfill and incineration data is also obtained from [1], included are leaching behavior and treatment efficiencies at controlled and uncontrolled landfill sites, incineration data including final emissions to air, water, and soil as well as energy recovery.
In addition to the environmental data described, the following economic parameters are included [5]:
1) sorting, registering, transportation, and buffer storage costs;
2) integral costs for shredding and separation; 3) costs and revenues at primary copper smelting; 4) costs at ferro and aluminum smelter processes;
5) costs at incineration sites, both MSW incineration and special waste incineration, also including charges for all environmentally relevant materials (concentration dependent);
6) costs at landfill sites, also including charges for all environ-mental relevant elements occurring in disposed consumer electronics (concentration dependency);
7) costs for plastic recycling including cleaning, upgrading, and color sorting;
8) disassembly costs based on disassembly times for standard operations;
9) revenues paid for all recovered materials. Including changes in metal prices over time.
The examples of the next section are based on the following assumptions and preconditions.
1) State-of-the-art recycling is based on current shredding and separation technologies as presented in [5] and checked by experts from TU Delft Applied Earth Sciences and a Dutch recycler.
2) Data is representing the Dutch take-back system for con-sumer electronics.
TABLE I
ECO-EFFICIENCY OFTREATINGDIFFERENTPRODUCTGROUPS
4) Costs for consumers for handing in products at a munici-pality, retailer, or other collection point are excluded from the integral costs.
5) The state-of-the-art recycling graphs and results are based on treatment of residue fractions in MSW incineration plants with energy recovery.
6) The Eco-Indicator ’99, Philips Best-Estimate, Hierarchic Perspective, Average Weighting set, weighting factor Re-source Depletion—Minerals adjusted to 5%, is used as a default environmental assessment [3], [11].
7) All examples and cases are presented under the assumption that for instance fractions sent to a subsequent processes fall under the acceptance criteria applicable.
All further data and methods are published in [5]. V. EXAMPLES
A. Increasing Collection Rates
Table I shows the outcomes of “saving products from the waste bin.” The results are based on [5] in which the reference point is Municipal Solid Waste (MSW) and state-of-the-art re-cycling in The Netherlands. The direction of the vectors is partly in the first quadrant as discussed in Section III as well as partly in the fourth quadrant where the “quotient” approach is applied. This counts for most of the products recycled where usually economic expenses and environmental gain is applicable due to prevention of new material extraction and net costs for all re-cycling stages together. The table shows that a limited number of products with a high intrinsic value due to their (precious) metal contents are ending up in the WIN/WIN quadrant where both environmental and economic improvements are realized. Note that this counts for the total outcomes and that probably not all stakeholders benefit from this, as there has to be paid for the collection and pretreatment phase to obtain revenues later on in the end-of-life chain.
The most important outcome of this table is that here the dif-ferent values of the difdif-ferent products categories are quantified. Basically, it demonstrates the important message in single num-bers that some products are more worth recycling than others. The numbers of Table I where WIN/WIN refers to the first quad-rant of Fig. 3, will be compared with other outcomes later on in order to compare the strategy of trying to collect and recycle more disposed products with other strategies. The remarks “pos-itive, high, and moderate eco-efficiency” are relative qualifica-tions for comparing the quotient values of the fourth quadrant
Fig. 4. Eco-efficiency of plastic recycling of housings.
for different categories of products dominated by respectively (precious) metals, glass, and plastic.
B. Plastic Recycling of Housings
The plastic recycling of housings manually being dismantled form many different products can also be evaluated with the QWERTY/EE method. The results show that this type of plastic recycling is eco-efficient for large sized housings, An impor-tant assumption here is the absence of flame-retardant and other contaminations in the housings. For all other plastic recycling cases calculated, the “quotient” must be calculated in order to balance the higher environmental gain against the extra costs in-volved. This is displayed in Fig. 3. In this graph, the size of the housings is displayed on the horizontal axis, the environmental gain per Euro (and the connected costs for disassembly) is illus-trated by the vertical axis. The reference point for this graph is the incineration with energy recovery of the plastic fractions at a MSW incineration plant with energy recovery. It is to be real-ized that the majority of consumer electronic products are on the left-hand (down) side of the graph. The large focus of the WEEE Directive on increasing weight-based recyclability targets and the resulting large focus on plastic recycling of products should be differentiated for the different product categories and the dif-ferent housing sizes involved. For medium and especially for small housings the eco-efficiency results are less positive com-pared to large housings.
In Fig. 4, a good correlation occurs between the integral costs for plastic recycling versus the environmental gain realized per euro invested. A large group of products with housings smaller than 100 g are in the bottom-left corner of Fig. 4. It can be con-cluded from this graph that the environmental gain per amount of money invested rapidly decreases for the smaller housings.
C. Level of Reapplication of CRT Glass
Fig. 5. Environmental level of reapplication of CRT glass.
Fig. 5 shows the environmental level of reapplication versus the recovery percentage of the glass replacement options under consideration. The points in the graph represent the environ-mental level of reapplication ( -axis) versus the “recovery” percentage (this is not the WEEE definition but the amount of material really reapplied in a “new product”). The initial value for primary CRT glass (100%) cannot be reached due to trans-port, cleaning operations, and energy needed for processing sec-ondary glass. The graph shows that the lower levels of reapplica-tion result in higher WEEE recycling percentages. An important outcome from this graph is that all secondary options contribute equally to the WEEE recycling targets, and that they are in re-ality not equally contributing to the environmental results. The conclusion on this issue is that lack of prescriptive “output” rules results in the effect that the environmental intent of the WEEE Directive is not served.
VI. ECO-EFFICIENCYDIRECTIONS
A. Eco-Efficiency Directions to be Promoted
Many different end-of-life strategies are evaluated with the QWERTY/EE method for many different products. These strategies included increasing of collection rates for the dif-ferent product categories, evaluation of plastic and glass recycling, analysis of the effect of dedicated shredding and separation settings for metal dominated products, and separate collection and treatment of cellular phones. Also, the different energy recovery options are assessed [7]. From this analysis, the directions with a positive, a negative and a “to be balanced” eco-efficiency are distinguished.
The options with positive eco-efficiency (higher environ-mental gain and lower integral costs, WIN/WIN situation) are as follows:
1) increase collection rates for precious metal-dominated products;
2) separate collection for precious metal dominated products with relatively high precious metal contents;
3) increase collection rates for metal-dominated products with relatively high precious metal and low plastic con-tents;
4) plastic recycling of large-sized housings without flame retardants.
B. Eco-Efficiency Directions to be Balanced
In Fig. 6, all “fourth quadrant” options with net environmental gain and net costs are ranked by environmental gain per euro invested. [7]. The ranking shows that the increase in collection rates should be prioritized in the following order: First for the metal dominated products, then for the glass dominated prod-ucts, and finally for the small plastic-dominated products. The increase in glass recycling leads to higher environmental gains compared to plastic recycling of the medium-sized housings and the prevention of fractions to be sent to a cement kiln instead of an MSW incineration plant.
Two options are leading to almost negligible environmental gains for the extra costs involved: The plastic recycling of small-sized housings and the “pick-up on demand” system of dis-carded electronic products. The latter is a collection rate en-hancing measure. Due to the very high costs involved for lo-gistics compared to the regular collection routes through mu-nicipalities and retailers is the resulting environmental gain in mPts per Euro is relatively low.
C. Eco-Efficiency Directions to be Avoided
A few options are to be avoided (LOSS/LOSS situation) from both an environmental as an economic perspective [7]. Two of these options are regarding the destination of plastic and residue fractions. These options are as follows:
1) incineration without energy recovery of plastic and residue fractions compared with incineration with energy recovery;
2) dedicated shredding and separation of metal-dominated products with a relatively high plastic content;
3) residue fractions from small- and medium-sized housings to cement kiln
VII. WEEE IMPLEMENTATIONROADMAP
With the QWERTY/EE approach it is possible to quantify pri-ority setting for collection (some products are more worth recy-cling, see the example in Table I), materials recovery (some ma-terials are more worth than others, see the example of Fig. 2), and processing (some secondary processing options are more eco-efficient than others, see Figs. 4 and 5). Based on these quantifications, the following roadmap is developed for more eco-efficient implementation of electronic waste policies. In this roadmap, the basic legislative instruments for improving end-of-life performance are reassessed:
A. Start on Basis of Available Technology: Key Elements
These elements are presented in order of importance: Economies of scale is contributing the most, followed by “outlet management, ” and last with design for end-of-life.
1) Economies of Scale: Achieving economies of scale is the
Fig. 6. Various “fourth quadrant” eco-efficiency directions.
the recycling and recovery targets are achieved per WEEE cat-egory or not. This is due to mixing multiple categories (like treating TVs and monitors from two individual categories on the same disassembly line).
2) Manage Outlets and Markets for Secondary Materials:
For recyclers, despite all prerequisites of the WEEE Directive, it is recommended to search for those outlet options first which results in the highest level of reapplication (see Fig. 5). This applies specifically for CRT glass, residue, and plastic frac-tions. (For metal fractions, the obvious destination is the corre-sponding available and preferably modern metal smelter). This issue is further discussed in the next part of this section on short term implementation and effective and efficient monitoring.
3) Design for End-of-Life: Besides the strategies which
in-crease environmental performance of products in end-of-life, as a starting principle, the environmental life-cycle perspective should be taken into account. In other words, sound eco-design in general should focus on reducing environmental burden of products throughout the life-cycle: in the production, use, and disposal phase. In [8], it is shown that replacing plastic housings of products by metal housings enables better compliance and en-vironmental performance of electronic products in end-of-life. However, this is achieved at the “environmental cost” of putting more environmental value in the products considered in the pro-duction phase and is leading to worsened overall environmental results. Within existing limits of the above life-cycle perspective and other practical limits like functionality demands, health and safety, appearance and looks, the degree of freedom to apply de-sign for end-of-life activities is limited to the following options as described further in [8]:
• improve connections, better unlocking properties; • avoid certain materials and materials combinations • reduce disassembly times
B. Short Term: Effective and Efficient Monitoring
Within the EU there are large differences in the development of take-back systems for electronic waste. It is recommended
to give room for technical and organizational developments of take-back systems in the short term. In this respect, the key el-ement enabling higher eco-efficiencies is well-targeted moni-toring by authorities. Within the different protocols that have to be developed by EU member states individually, the measuring and reporting of the inputs and outputs of recyclers (instead of their treatment activities themselves!) enables controlling the system performance. In this respect, the various national mon-itoring protocols should encourage, avoid, or balance the three directions as described in Section VI.
Generally speaking, the main available avenue for in-creasing eco-efficient take-back system performance within the boundaries of the already-enacted WEEE Directive is by monitoring and steering the inputs and outputs of recyclers instead on putting too much focus on environmentally flawed weight-based recycling targets (Figs. 2 and 5) and restrictive treatment rules for recyclers.
C. Long-Term Review
In the long-term legislative development of WEEE, but also for waste policies in general, the following revision is proposed, based on the insights obtained with eco-efficiency analysis.
1) Collect More Data and Insights: In order to come to a
2) Rebalance Policy Strategies: Already now, general
direc-tions on how to alter policies strategies on the long term become clear.
1) Weight-based recycling targets should be altered, or be dis-carded completely, or be replaced by more accurate (as well as more streamlined) environmental equivalents (see Figs. 2 and 5),
2) Treatment rules, except those necessary for health and safety reasons, can also be discarded, whereas in most cases environmental and economic optimization of re-cycling operations is directed similarly and thus can be left to the recyclers themselves. This also avoids many monitoring problems in practice, which can be done more effectively by following and measuring the inputs and outputs of recyclers. In particular, the rules for printed cir-cuit boards, CRTs, plus fluorescent powders, electrolytic capacitors, and for brominated flame-retardants need to be reviewed.
3) Differentiate in collection targets (see Table I). Some prod-ucts are more worth being recycled from both an environ-mental as an economic perspective. One general collec-tion minimum per inhabitant should maybe be differen-tiated, or more effort should be done to prevent leakage streams of disposed products: More focus should be given on (precious) metal-dominated products, medium priority on glass-dominated products, and lower priority on small plastic-dominated products. Summarized: differentiate and control the inputs of the systems better.
4) Focus on “outlet rules.” The example of the reapplication of glass of Fig. 5 (and others) shows that by monitoring the outputs of recyclers, much higher eco-efficiencies can be achieved than the current set of rules used in the WEEE Directive. Prescribing which fractions should follow which secondary treatment routes as a minimum is also very prac-tical, while take-back systems are controlled better this way (in particular, this applies to the destinations of plastic, glass, and residue fractions)
5) It is recommended for system organizers and authorities to enable the exploration of the most eco-efficient options of Section VI, Fig. 6 first. This is also needed to further stim-ulate technological developments in the long term. This issue specifically applies in the fields of automated disas-sembly, efficient identification and sorting techniques for different materials and components (plastics), and the de-velopment of secondary outlets or markets for secondary materials, for instance in finding useful thermal applica-tions for shredder residue fracapplica-tions.
6) In contrast with wide-spread belief, for producers there are (limited) eco-efficiency improvement options possible in design for end-of-life related to expected end-of-life treat-ment configurations [8].
VIII. DISCUSSION
Generally, it can be concluded that addressing costs and revenues in relation to environmental costs and revenues on a quantitative way, is a powerful concept in rethinking about the eco-efficiency of the end-of-life of consumer electronic
products. Furthermore, better insights in the system perfor-mance and the demands and constraints of secondary material processors are obtained. The concept places the best possible and state-of-the-art environmental quantifications in an eco-nomic context, addressing the environmental effectiveness of for instance the WEEE Directive in relation to actual costs efficiencies. With the concept, the following aspects can be addressed:
1) performance of a single product in different end-of-life sce-narios;
2) contribution of individual materials and material fractions to this performance;
3) the consequences and contributions of single stakeholders; 4) the eco-efficiency effects of possible changes in design,
policy, technology, logistics, and system organization; 5) optimizing the relation between recyclers (fractions) and
secondary material processors or final waste processors. The eco-efficiency results derived with the QWERTY/EE method appear to be very consistent and not very sensitive to the choice of the underlying environmental assessment method, except for plastic recycling [7]. This is less preferable under other environmental assessment methods not addressing resource depletion of fossil fuels.
IX. CONCLUSION
The diversion in eco-efficiency directions has lead to the following conclusions regarding the current use of policy strategies [7].
1) Weight-based recyclability targets of the WEEE Directive are in too many cases leading to undesired eco-efficiency directions and in a few cases even to lower environmental performance. The current recyclability targets should be abolished completely and replaced by mandatory treatment and outlet control rule. These outlet control and treatment rules are also far easier to monitor.
2) At the same time, collection rates should be split per product category. Especially for metal dominated and precious metal-dominated products, higher percentages should be prescribed and enforced. Collection rates en-hancing measures must be applied with precaution in order to limit high costs for collection and logistics, especially for small products.
3) Recyclers should determine themselves when to apply ded-icated treatment of metal-dominated products, while in this case environmental and economic optimization is directed equally. No treatment rules are necessary in this case. 4) A separate collection system for precious metal-dominated
products with precious metal content above certain concen-trations should be prescribed or encouraged.
In cases where take-back systems have not been defined yet, as for instance in the U.S., it is recommended to adopt the above strategies instead of using a weight-based approach as done in the European WEEE Directive.
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Jaco Huisman received the M.S. degree in chemical
engineering from Eindhoven University of Tech-nology, Eindhoven, The Netherlands, in 1999 and the Ph.D. degree from Delft University of Technology, Faculty of Design, Construction and Production, Design for Sustainability Program, with the thesis entitled “The QWERTY/EE concept, Quantifying recyclability and eco-efficiency for end-of-life treat-ment of consumer electronic products.” Currently, he is continuing his work at Delft University of Tech-nology as a Postdoctoral Researcher in commission of the Dutch Ministry of Environment, Philips Consumer Electronics—En-vironmental Competence Centre and NVMP (Dutch take-back system for electronic waste).
Also, he started his own part-time consultancy company, Huisman Recycling Research.
Dr. Huisman received two Best Paper Awards for publications in IEEE conference proceedings, in May 2000 for “Environmentally weighed recycling quotes—Better justifiable and environmentally more correct,” Proc. 2000
IEEE Int. Symp. Electronics and the Environment, San Francisco, CA, and in
December 2003 for “Balancing Design Strategies and End-of-Life Processing” for the Ecodesign 2003 Conference, Tokyo, Japan.
Ab L. N. Stevels received the degree in chemical
