A comprehensive multi-level circular economy assessment framework

Abstract

With several industries shifting from the conventional liner to circular economy (CE) models, it became necessary to develop standard tools to assess the circularity of different products and processes to facilitate this transition. The conducted thorough literature review presented in this paper concludes that most circularity assessment tools lack comprehensiveness and objectivity due to complexities that arise from the quantification processes of qualitative data, the extensive use of linguistic terms, and the difficulty in combining more than one indicator in case of similarity, dependency, or both. Thus, this paper aims to develop a comprehensive CE assessment framework that is capable of assessing the circularity of processes and products from a wide range of industries and sectors. The framework developed enables a comprehensive assessment by incorporating a step-by-step indicators selection procedure that covers the micro, meso, and macro CE levels of implementation. Also, the framework is capable of dealing with quantitative as well as qualitative indicators while limiting uncertainties associated with linguistic terms. This is achieved by incorporating fuzzy logic into the assessment framework. Moreover, it offers flexibility in selecting between subjective and objective assessment methods through the integration of several Multi-Criteria Decision-Making (MCDM) methods that are also used to rank the assessed processes or products based on their circularity. An example was presented to validate the applicability of the framework and to guide users on to how to draw conclusions about the circularity of the assessed objects from the scores obtained. In the example, the circularity of Friction Stir Back Extrusion (FSBE) is assessed against the circularity of conventional extrusion. FSBE achieved a relative circularity score of 69.23% compared to 30.77% for conventional extrusion. In future, it is encouraged that policymakers and experts collect and build databases of indicators of their own fields to ease the circularity assessment and enhance its consistency.