Product design and recyclability: How statistical entropy can form a bridge between these concepts - A case study of a smartphone

Abstract

The concept of Circular Economy has made a crucial contribution to establishing a changed perspective on recycling, one in which recycling is no longer regarded as merely a part of waste management, but rather intimately linked with preceding stages of production, such as product design and manufacturing. It has been shown that recycling achievements significantly depend on the inputs into recycling processes where complex products require higher recycling efforts. To promote transparency with regard to both product design and its impacts on recycling, the assessment of product recyclability is highly relevant. Current recyclability assessment methods neglect to assess product recyclability from the design perspective or are based on parameters that limit comparability between different products. Thus, there is a gap in assessment methods for product recyclability based on design decisions. We developed a recyclability assessment method for products that incorporates fundamental product information on material composition and product structure in a simple and concise way. The assessment approach is based on statistical entropy, which is a well-established metric for the evaluation of material distributions. To demonstrate the applicability of the Relative product-inherent recyclability (RPR) assessment developed, a case study is presented in which a modelled smartphone is investigated. The results show that statistical entropy is a valid measure to assess the recyclability of products at the stage of design and thus helps to identify weaknesses in product design. The new metric is intended to address product designers and manufacturers to enable improvements in product design and comparisons between different products. Overall, it should promote the strategies of the European Circular Economy Action Plan regarding product design and recycling.