Contribution of Material Flow Assessment in Recycling Processes to Environmental Management Information Systems (EMIS)

Alexandra Pehlken, Martin Rolbiecki, André Decker, Klaus-Dieter Thoben Bremen University, Institute of Integrated Product Development Badgasteinerstr. 1, D-28359 Bremen [email protected]

Abstract Material Flow Assessment (MFA) is a method of analyzing the material flow of a process in a well-defined system. Referring to the life cycle of a product the Material Flow Assessment is part of a Life Cycle Assessment (LCA) and provides the possibility of assessing the environmental impact of a process and product respectively. Applying these methods to recycling processes the potential of saving primary and secondary resources may be measurable. The presented paper will give an overview on the strategy how MFA can contribute to Environmental Management Information Systems (EMIS).

1. Introduction Recycling processes can contribute to lower environmental impacts because they possess a huge potential of secondary resources. The input of a recycling plant is no longer considered as waste stream; instead it is high valuable material that enters the recycling process and the output is even more valuable. Due to the fact that residues always vary in their composition and material flow only data ranges can be used as input parameter. A simulation of recycling processes is therefore often difficult. Notten and Petrie (2003) substantiate the statement that “different sources of uncertainty require different methods for their assessment”. Therefore, recycling process models rely not only on the quality of the process data but also on the uncertainty assessment. The last years there are more and more models developed that include the assessment of uncertainty in recycling processes of waste management (Xu et al., 2009; Tian et al., 2006; Christensen et al., 2007; Refsgaard, 2007). Material flows are main parameters to look at because their characteristics influence the success of the following processing steps.

2. Material Flow Assessment and Life Cycle Assessment in Recycling Processes Life Cycle Assessment (LCA) covers the entire lifecycle of a product, process or activity. According to the International Organisation for Standardisation (ISO), an environmental lifecycle assessment is analysing the environmental interventions and potential impacts throughout the life (from cradle to grave) from raw material acquisition through production, use and disposal. During the whole life cycle of products and materials the amounts of materials involved, the inputs of energy and water resources along the life cycle, the amounts of waste materials and the associated environmental impacts all along the product chain have to be assessed. Material flow assessment (MFA) clearly is useful here, but it can be only a part of the whole equation. MFA can illuminate the amounts of materials involved and the amount of material waste, but it does not include all the information necessary to assess potential impacts on the

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environment. With regard to material management MFA must be used in conjunction with other types of data (Allen et al, 2009). A short history of MFA and can be found in Binder et al (2009) and is going back to the roots of the 1960’s to studies on material balances. The publication of Brunner and Rechberger (2003) is now established as a textbook in the application of material flow assessment. Since the input in recycling processes is often a mixture of various material streams the exact composition is never known. There is often a lack of information due to unkown parameters in material composition or process steps (Pehlken et al, 2009). Due to the high potential of recycling processes to contribute to a sustainable management of resources (e.g. energy savings and material efficiency) it is necessary to assess the material flows with the regard to their environmental impact (Bringezu et al, 2009; Salhofer et al, 2004). To assess a sustainable resource management the following conditions for a reasonable recycling process have to be achieved: Adequate material mass for the recycling process Adequate material mass for further product manufacturing Defined material properties Very little variation of material properties. It is desirable to forecast the above mentioned conditions for choosing the processes with the best performance. A rough prediction on material flows, costs and environmental impacts can be assessed through combining the methods material flow assessment (MFA) and Life Cycle Assessment (LCA). While performing an LCA it is possible to evaluate the environmental impact as carbon footprint, water footprint, ecological footprint and others (Ekvall, 2007; Fatta, 2003; Hashimoto, 2004). But (as mentioned above) these methods lack of the description of material properties, their variations and uncertainties respectively. Material flows should rather reflect a fundamental basis than being reduced to the assessment of mass and volume. Future prospects of the quality of secondary resources, including their input and output properties may be helpful to assess their potential to substitute primary resource for example. Information on material properties generated with LCA and MFA can contribute to the product design, the production phase and the recycling performance of a product.

3. Concept and System Architecture

3.1 Overview Recycling processes generate material flows in various qualities. A complete separation of waste material components is not possible but quality standards can be met through defining separation grades as categories (high, medium, low). Therefore, modeling is useful to describe the correlation of material properties. Please note that the modeling in recycling processes is not related to specific data (numbers) but rather to data ranges (or quality issues). The modeling can help in decision making processes if the uncertainty of the model has an acceptable level. The acceptable level depends on the aim of the modeler and the model user. Assessing the information of the processing steps for modeling purposes with the availability of data ranges and the focus on uncertainties is necessary for the model system. Uncertainty can be understood as the variation of a parameter in a model. This variation is not known and at random. Additionally data- defects can be located in recycling processes due to incomplete or missing data (Marx-Gómez et al, 2004). Modeling recycling processes and the assessment of uncertainty and data defects regarding the input and process parameters are firmly connected.

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3.2 Knowledge of information The management of material flows with regard to their material properties provides information for EMIS that supports the planning of (secondary) resources (see figure 1). Product and material recycling in combination with the applied recycling technique will provide information on material flows with specific material properties. This information can help in assessing the potential of 1. the long term availability of material streams (sustainable resources) 2. the potential of substitution of primary resources with secondary resources (saving primary resources) 3. the efficiency of recycling processes (energy and material savings)

In addition to the evaluation of recycling processes and their material flows the overall potential of the available waste streams has to be taken into account while assessing the material flow of recycling products. The life time of a product and the consumer’s behavior plays an important role in predicting the availability of material flows.

Environmental EMIS Impact Resource Management Recycling

LCA MFA Life Cycle Assessment Material Flow Assessment

Figure 1: Contribution of MFA and LCA to EMIS

Material Properties

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3.3 Architecture The combination of MFA and LCA with the description of material properties needs the evaluation of materials streams. A Knowledge-Based Decision Support System delivers the structure for the procedure (see figure 2). It uses mainly the information generated by processing steps resulting in an abstract combination of the elements of the model and its linkages. Therefore, this technique allows developing the model. Instead of specific data it processes the information of a process (e.g. dismantling of waste products into components of different shapes and compositions). Collecting information can be made accessible through existing databases like ecoinvent (ecoinvent Centre, Switzerland) or recycling stock exchanges. While calculation input data with program interfaces and the support of Knowledge-Based Decision Support System output data can be generated. The accuracy of the model relies on the data availability and its quality. Therefore, it is necessary to have a well operated network.

Figure 2: Architecture of the Knowledge-Based Decision Support System

3.4 Material Management For developing new products most input materials are primary resources and can be described in their properties since nearly all suppliers of resources participate in a quality management system and provide all their details on material streams. In most cases material streams generated from recycling processes (secondary resources) cannot compete with primary materials because secondary resources are often a mixture of various components. There is a chance that secondary resources are able to substitute primary resources if the information on their properties is complete and provided through an information system (van Schaik et al, 2010). Referring to supply chain management, the model can be used to manage the substitution of primary resources with secondary resources. A parameter of high influence for the process performance is the homogeneity of material streams which is dependent on the sorting and separation success of recycling plants. An example gives the recycling of scrap tires. At the end-of-life of a tire there is information available on the brand, life time, kind of seasonal tire (winter, summer or all season), passenger or truck tire and much more. Besides this information it is never possible to get to know the exact tire composition (because of company secrets) that represents the input of a recycling plant.

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The management of product life cycle includes the best knowledge of processes, their materials and their system boundaries. Attention has to be paid to uncertainties in performing LCAs in recycling processes. Life cycles of secondary resources are often identified as open loop processes (conversion of material from one product into a new application) compare to closed loop processes (conversion of material into the same application) (see figure 3). While characterising the output material stream of the first life cycle the input material stream of the following life cycle is characterised as well. This lowers the uncertainty and makes it more likely to substitute primary resources as well.

Primary Raw Material Production

Open Loop

Product Manufacturing Product A

Product in Use

Losses Presence

Raw Material Production Future

Secondary Raw Recycling Product Material Manufacturing

Product in Use Product B

Loss es

Recycling Secondary Raw Material …

Figure 3: Open-Loop Recycling Process

Secondary resource management is important to provide sustainable production processes. Secondary resources help to preserve our primary resources. Recycling processes differ from process to process and the input material has a high influence on the process performance. Uncertainties belong to most (recycling) processes and have to be taken into account when developing a model. Implementing the information on secondary resources and their properties in a model that can be accessed through supply chain management system this model can support the substitution of primary resources through secondary resources. Additional the model can provide information on the recycling potential of a product that may be essential to meet environmental constraints. This is only possible through describing material properties. Material flow assessment with a special focus on material properties is presented as a useful method to develop a tool for sustainable supply management.

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4. Conclusions and outlook Material Flow Assessment can contribute best to Environmental Management Information Systems (EMIS) if the material flows are characterized. Through the knowledge of material properties of various secondary resources the materials can be reused in products and substitute primary resources. This is only possible through a network between recyclers (recycling stock exchange) and the information on material flows and their properties respectively. A Knowledge-Based Decision Support System delivers the architecture for the information exchange. It is intended to increase the material efficiency and to establish a sustainable resource management in industrial processes with the described system. More research on the topic is necessary to realize the support system. Especially the information on material properties received from recycling processes needs a lot of attention as well as the fact of data defects.

5. Acknowledgement This research project is funded by the German Research Association DFG. The authors thank for the support.

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