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October 7, 2007 / or4green

Paper on WEEE returns strategy

The paper summarized below is part of an upcoming EJOR issue on closed-loop supply chains, mentioned earlier. It includes an integer program and connects to cradle-to-cradle ideas with its emphasis on “Design for Dissassembly and Recovery”.

Strategic response to EEE returns: Product eco-design or new recovery processes?
R. Zuidwijk and H. Krikke
in European Journal of Operational Research
doi:10.1016/j.ejor.2007.08.004
Notes: This paper looks at possible strategic responses of electronics industry firms to WEEE. As the title suggests, strategic approaches are divided into product design and processing of recovered products. Strategies to handle WEEE can be implemented at either end, or both simultaneously. On the design side (or “eco-design” as the authors label it), “Design for Disassembly and Recovery (DfX)” and “Product Data Management (PDM)” are considered. The inclusion of DfX is what links the paper to the cradle-to-cradle philosophy. For instance, one of the goals of DfX listed in the paper is “to make material fractions more homogeneous so they can be separated more easily”. Under PDM, products maintain information about themselves over their life-cycles, providing industry with data on the installed base and consequently on the recovered products.

After a nice overview of WEEE, the authors outline the strategic responses and discuss some background literature. X-ray technology is mentioned as one of the methods used to assess the content of recovered products (this was also mentioned in the batteries paper summarized here). The authors claim that a key contribution of the paper is that it considers the integration of eco-design and advanced process technologies. They make the interesting observation that a reason the overlap has not been studied much may be that, both in industry and academia, these two areas are studied/managed by people in different disciplines/locations in the supply chain.

Within product/module/component recovery, the basic decision to be made is between recycling and remanufacturing. The problem is modeled in different ways depending on the level of product information being assumed. Under full product information, the problem is posed as an integer program. The objective is to maximize profit, which consists of remanufacturing and recycling revenue (some of which may be negative) minus disassembly costs. Constraints are primarily flow balances from products to modules to components across the various processes, but also include WEEE recovery quotas for given materials. Under partial information, the IP is replaced by a set of decision rules. In the absence of any information, a “default strategy” is used.

The models are applied to the recovery of computer monitors under differing levels of information and with different combinations of strategies on both the design and recovery ends. As might be expected, DfX comes out favorably because it aids in remanufacturing as well as in reducing recycling costs because of its better separation of materials. It reduces the importance of complex processing technologies and information tracking. The authors point on that the IP is fairly generic and can be adapted to other industries.

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