Decomposition At End Of Life

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Journal of Cleaner Production xx (2005) 1e7 www.elsevier.com/locate/jclepro

A decomposition of the end of life process P. Tanskanen*, R. Takala 1 Nokia Research Center, Nokia Group, P.O. Box 407, Helsinki FIN 00045, Finland Accepted 11 November 2005

Abstract New legislation on electronics waste in Europe will set formal requirements for product end of life (EOL) processes. These include producer responsibility for obsolete product take-back, pre-treatment and recycling. A structure is needed for the complex interactions between technical, environmental, socio-economic and legislative factors in product take-back and EOL treatment. EOL process can be divided into three distinct stages with different characteristics and stakeholders. The first stage is the organization of an effective take-back process. The second is the structural pre-treatment and fragmentation of the product. The third stage is the recycling and disposal processes of the product material content. In this paper we propose a simplified economic model for an EOL process for mobile terminals. We use the model to create a step-by-step EOL process. Furthermore, we present through examples, technical as well as engineering process solutions in promoting economic implementation of the EOL processes. Ó 2005 Elsevier Ltd. All rights reserved. Keywords: End of life; Recycling; Life cycle; Economics

1. From the system level to an EOL process In order to be able to solve a complex multifaceted problem of end of life (EOL) management, the problem must first be defined and partitioned into meaningful parts. A model of the EOL is presented based on the work in the area of mobile phone EOL treatment and it is shown in a larger context. The problem is also decomposed so that specific solutions can be found [1e4]. The EOL is the last phase in the lifespan of a product. It has been one of the primary topics of environmental discussions during the past few years. This topic is at the source of much activity as familiar waste treatment issues now also concern electrical products. However, the EOL stage represents only a part of the product life cycle and environmental impacts, as seen from the distribution of the environmental * Corresponding author. Tel.: þ358 7180 37628; fax: þ358 7180 37128. E-mail addresses: [email protected] (P. Tanskanen), roope. [email protected] (R. Takala). 1 Tel.: þ358 7180 20860. 0959-6526/$ - see front matter Ó 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.jclepro.2005.11.016

effects of a mobile terminal during its life cycle, in Fig. 1. This is relevant when the product ends up into proper end of life treatment and is not landfilled or incinerated. Even if the EOL is only a part of the whole picture the activities within the EOL phase need to be clarified and partitioned in more detail. This has to be done to allow concrete implementation of a sound EOL process and to enable the development of technologies to promote these processes. Fig. 2 describes how the EOL can be shown in a larger context. The figure shows how the EOL is related to the overall environmental thinking regarding electronic products and shows the levels of abstraction from a general view to concrete engineering solutions. This is drawn in the shape of a funnel, to show the shift from large abstraction to more defined and limited views and to concrete solutions. The levels of abstraction shown are: the system, process, technology, and individual solution levels. The system level describes the whole environmental impact of the product. We have opted to use the term system as there is a network of actors and a product’s environmental impacts can be viewed from many different angles, such as energy consumption,

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Fig. 1. Environmental impacts of a mobile terminal during its life cycle. The number of x’s signifies the amount of impact [5].

packaging material, manufacturing, and so on. Tools for these are, for example, supplier network management, design for environment (DfE), environmental management systems, material data management, and guidelines for end of life practices. The process level describes the processes and interaction activities of the different parts of the system, which in this example is EOL. The third level concentrates on the technologies and methods needed for implementing one process, such as take-back or fractioning. The fourth level looks at individual design solutions for products that can help achieve environmental targets for a certain technology. A similar leveling down could be done also for other environmental processes at the system level. In this paper we concentrate on the last three levels of abstraction as the highest level of abstraction is already well covered in literature [6e9]. We show a model of the end of life activities for an electronic appliance, a mobile phone. From the process model we derive technologies that can be used to target individual technical solutions in a meaningful way so that the whole environmental framework can be addressed by tackling individual parts of it separately. This paper concentrates on the final treatment of obsolete electronics products. Reuse, upgradeability, refurbishment and other means to extend a products live are not considered here as these are seen as activities that are done prior to the EOL treatment [10]. 2. A model of the EOL process The process view of EOL can be modeled into three distinct phases: take-back, pre-treatment, and material content recycling and disposal of the products. Take-back involves the logistics, systems, and technologies for the collection of obsolete products and transferring these products to recycling

facilities. In this phase the user of the product plays a crucial role, as he initiates the whole EOL process. The take-back is critical to the EOL process, as its success determines to what detail the subsequent EOL processes can be tailored. The take-back phase can be characterized as an organizational issue. Pre-treatment includes sorting of the products and their disassembly or shredding. This is done by recycling companies utilizing different technologies, from manual treatment to more automated systems. The ease of this phase depends on the mechanical structure of the product. Content recycling and material disposal include the sale or disposal of the materials/components according to what is appropriate for each fraction. In this phase the value of the material is defined by the global material markets. An economic model for the EOL process of mobile terminals can be presented based on these three phases. The model describing the three phases is shown in Fig. 3. The costs of the different phases are normally combined and shown only as one figure. In the model the cost of each phase can be separated, and therefore the transparency of the system is greater. The model shows the financial bottlenecks in the EOL phase and enables identification of key issues where action needs to be taken. In the model, the individual cash flows of the whole EOL process can be identified. By separating the three phases and identifying the roots for positive and negative cash flows, it is possible to find ways for maximizing system efficiency. The cost of EOL is related to the two first stages, take-back and pre-treatment, and to the treatment of hazardous substances in the product. Revenues in the process come from the sales of recyclable material and reusable components. The amount of revenues therefore depends on the amount of precious and recyclable materials in the product. The final bottom line is from the sum of the relations of four factors: the fractions suitable for sale, hazardous materials, and the complexity of the product structure and the efficiency of the take-back system. In mobile phones the precious metal content is typically quite high and therefore recycling shows positive value when logistical costs are not taken into account. The model can therefore be used as a tool for pinpointing the expenses and revenues from the EOL process. After this it is easier to decide on the necessary improvements to be made in the process, whether they are related to product design, take-back or recycling activities. The two first phases, take-back and pre-treatment, offer no direct economic benefits, but rather require investments in systems and facilities. Controlling cost formation in these phases is important as only the sale of recyclable materials and reusable components offers economic benefits. The incineration of plastics is considered to be a zero sum activity. The financial benefits are evident only in the last phase, which means that the earlier, costly, phases must take place before the benefits can be collected. In order to obtain a sustainable comprehensive solution it is therefore desirable to build up enterprises, which can include both expenses and profitable activities in their portfolio. The model also describes the logistical network of the product EOL. The organization of take-back is the main logistical

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Fig. 2. The context and levels of abstraction of EOL.

challenge, as the products must be collected from widely dispersed customers around the world. Products need to be transported from the collection points to predefined recycling facilities. Material fractions are further transported to different material companies from the recycling facilities. For total system efficiency, an optimization of EOL logistics is important. By building up a process from the different phases it is possible to start searching for various solutions to the issues in each phase. We can then move down one level of abstraction and start to look at technologies and methods for the processes. We have derived a simple step-by-step process from the model to describe the activities that need to take place in the EOL. The process, shown in Fig. 4, consists of six phases. The initiator of the take-back process is the user. Mobile phones enter into the EOL phase when the user (owner) decides not to use the product anymore and returns the product to a collection point. It is extremely important to motivate the user to do this in order to get back the products and route them for proper EOL treatment. The second phase is the activity that takes place during the take-back processes. This starts when the terminal is returned to the collection point [11]. Take-back systems and routes currently depend very much on the location; different systems have been described in several publications [12e16]. After the appliance/terminal is returned to the collection point it is moved to sorting, which is the third phase. Products

are sorted according to their economical value and according to their different material compositions. The following phase is product disassembly, for example batteries are disassembled from the product. The fifth phase is separation of different material fractions, for example separation of glass displays from the circuit boards and plastics. These three phases (sorting, disassembly, and fractioning) represent the pre-treatment phase in the EOL process (Fig. 3). The last process phase is the sale or disposal of materials, and it forms the recycling and disposal phase in the EOL model. 3. Technological and design solutions for disassembly In order to further explain the need for structuring the pretreatment phase of the EOL process, it is necessary to look at it more closely. The purpose of pre-treatment (sorting, disassembly, and fractioning) is to separate different material fractions as efficiently as possible from the obsolete products. This is done in order to be able to sell as much material as possible to be used as raw material for new products and at the same time safely remove hazardous and other duly disposable material fractions. Different technologies can be used for pre-treatment. Pretreatment can be done manually (Fig. 5), by shredding (Fig. 6) or by various automated processes (Fig. 7). All of these methods have their benefits and limitations. General

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User

Take-back

Sorting

Disassembly

Separation fractions and components Sale/disposal of fractions Fig. 4. EOL process.

Specific technologies and solutions for issues arising during the process phases can be addressed from understanding of the problem partitioning gained from the process view of the EOL model. It is possible to create technological solutions for streamlining activity related to these process phases. The take-back, sorting, and disassembly phases described earlier have been studied. In order to illustrate how specific technologies can be used to solve EOL problems, a closer look is

Fig. 3. Economic model of EOL process.

goals for the processes are cost-efficiency, product diversity, and flexibility, high product flow, safety, and good separation capability. We can view EOL solutions in more detail by studying more closely the newest disassembly technology, automated disassembly. We have introduced examples of active disassembly [2e4] and induction heating [17]. After moving from the abstract level to a specified EOL technology using a process model, specific design guidelines can finally be drafted to provide a real solution for a coherent EOL practice.

Fig. 5. Manual disassembly.

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Fig. 6. Shredding plant.

taken at automatic disassembly as one solution for the disassembly of electronics. Currently two lines are being pursued to gain efficiency in mobile phone disassembly. The first is to generate more sophisticated and effective disassembly processes. The second is to design a disassembly function into the products themselves. In the next section some solutions to

these specific problems are presented; they are examples of solutions that address EOL problems step-by-step. Several options have been developed to solve a specific problem. The nature of these options may vary significantly, and they cannot in all cases be implemented in parallel. This means, that in order to solve a problem, one option must be selected.

Fig. 7. Automated disassembly technologies (robotics, induction heating [17], mechanical impact, and active disassembly [3]).

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3.1. Process related solutions for disassembly Several cases of improved disassembly processes have been demonstrated. Fig. 7 shows different automated disassembly processes for mobile phones. The problem with the most automated technologies is that they are quite product specific and require positioning of the product. 3.2. Product related solutions for disassembly In order to be able to go to the product design level one option must be selected from the different technologies. Here built-in disassembly is taken as an example and one technical solution is shown. A built-in disassembly system is a feature or component that can be triggered by a simple outside force to open the phone structure. Several designs that accomplish this task have been presented [2e4] in previous works. Common triggering forces for self-disassembly (or active disassembly) are heat and a magnetic field, or even chemical or biological agents. The mechanism called ‘‘Fall apart’’ is shown in Fig. 8. The device is based on the magnetic triggering of the fastening element. A magnetic field will unfasten the element, disassemble the product and allow the separate treatment of different parts as separate fractions. The mechanism was realized by designing a screw-like discrete component that resembles the antitheft tags used in clothing stores. This mechanism, however, was designed so that manual disassembly is also possible, enabling mobile terminal disassembly also without a strong magnet. The development of this solution is on prototype level where implementation to mass-production has not yet been done. 4. Factors restricting EOL implementation When taking any EOL solution into use participation and buy-in are required among all the players involved. As in the example shown earlier, the built-in disassembly mechanism has no use, if the pre-treatment facilities for using it are not in place.

Decision-making concerning the example presented is at the moment rather difficult. The end of life treatment of electronics is a rapidly changing and developing area where new technologies and practices are constantly being created. Therefore the feedback information from the end of the life processes to product design is not up-to-date. The delay between the design of a product and its recycling is several years, which affects the compatibility of these two ends of the products’ life cycle. Recycling can be approached from two directions: how to design a product that can be easily recycled, and how to build a recycling process that works in an efficient way. The challenge is to approach the same solution from both of these directions, and this hampers decision-making significantly. The products’ design has to be optimized to facilitate a manual sorting process. However, if an automatic take-back machine sorts the product automatically, it is bound to be sub-optimal with such a design. Decision-making is also slowed down by overly general design guidelines. Gradually DfE has been included in the design guidelines within the electronics industry. In practice at the beginning, this means the use of lists and guidelines, e.g., using only one type of screw, minimizing the number of screws, not combining metal and plastic materials. These instructions are effective for manual disassembly but not necessarily for automated processes. However, as we have shown here, the end of life processes for disassembly and material separation are developing very fast. The recycling industry cannot rely on manual work in the future. For this reason general guidelines result in ‘‘good compromises’’. In these compromises a product is designed to have some favorable characteristics for diverse processes but is not optimized for any processes. The difficulty at the moment is to design for practices that are not yet established. This uncertainty prevents radically new thinking in end of life design, and so companies only make minor amendments. At the moment it is not clear what material fractions need to be separated in the electronics products. As an example, the plastic covers of the phone can be separated and recycled, but it is not eco-efficient at the moment [18]. This is because the total benefit is negligible when the small weight of the received material is compared to the energy required for receiving it.

5. Conclusions

Fig. 8. Built-in active-disassembly system, which can be triggered by a strong magnetic field.

Both new environmental legislation and discussions related to electronics products have been concentrating to a large extent on recycling and hazardous material issues. This happens even though the recycling phase accounts for only a fraction of the environmental impacts of the product life cycle [5]. Much attention is paid to the EOL because of the large amount of electronic goods in use that should not end up in landfills, and because of the risk of hazardous substances leaching into the soil and water systems. With this in mind, a closer look was taken at the EOL, and a detailed model was created for this phase. The model describes the EOL against the general background of environmental issues, having regard to problems and options as well as detailed technical solutions.

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An important way to lessen negative impacts is to educate and guide consumers so that they are aware of the separate collection of electronics products. In addition, removing potentially hazardous substances from the products is an important design effort, because some products may end up in landfills even though they are collected separately. These two issues are handled by organizational agreements, information sharing, and material selection processes. The phase in the middle of the EOL model is still very immature, and it was taken under closer scrutiny in this example. After the goods have been collected and transported to the treatment plants, an efficient process should be in place so that as much as possible of the material content will be collected in way that is safe for the workers and the environment. Designing an easily recyclable product and/or better treatment processes in cooperation with partners can enhance this process. There exist a great number of solutions for this phase; but the state-of-the art solutions in use today are manual disassembly and shredding. Of the new technologies, a promising one is active disassembly; to highlight this, one detailed product concept was presented. In order to be able to concentrate on a specific issue in the EOL, a model was described through an example. Decomposition of the process leads to specific problems, for which practical solutions can be found. Before a radical change can happen in the EOL decisions must be made on which options to select from the constantly increasing number of available options must be made. Acknowledgements The authors would like to thank the students of Helsinki University of Technology who helped realize many of the active-disassembly prototypes, as well as EU 5FP ADSM project collaborators for their valuable input in developing the ideas. References [1] Tanskanen P, Takala R. Engineering paradigms for sustainable design of mobile terminals. 14th International conference on engineering design, ICED, Stockholm; 2003.

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