On the Adoption of Circular Economy Concepts in the Manufacturing Sector

Abstract

Industrialization has brought wealth, prosperity, and abundance to many nations. However, it has had many drawbacks on people’s health and the environment. Several paradigms have been proposed and implemented in an effort to suppress and reverse the adverse impacts of human activities and industrialization. A popular approach is the circular economy (CE). CE is a waste conservative model that limits resources uptake, waste generation and energy consumption. The implementation of today’s top-notch technologies such as Industry 4.0 tools is a necessity to enable the transition from the conventional linear economy to the CE. Moreover, to ease this transition, it is important to be able to assess the circularity of different products and processes along the way. Most available assessment procedures lack comprehensiveness and objectivity due to complexities such as the quantification processes of qualitative data, the extensive use of linguistic terms that represent data and the uncertainties associated with them, and the difficulty in combining more than one indicator in case of similarity, dependency, or both. The aim of this thesis is to firstly present a thorough review on the applications of cyber-physical systems within each of the CE stages and highlight their contribution to the attainment of the different sustainable development goals through several practical examples. Secondly, it presents a comprehensive CE assessment framework that can assess the circularity of developed and developing countries, different industries, wide range of processes, and different products, of both private and public sectors on a micro, meso, and macro levels. This is achieved through a step-by-step indicators selection procedure and the combination of fuzzy logic and multi-criteria decision-making methods which deliver a CE assessment that eliminates previously mentioned problems and result in an unbiased realistic ranking of alternatives. The presented framework is implemented to assess the circularity of Friction Stir Back Extrusion against conventional extrusion methods. Results show a higher circularity score for the FSBE (48.9%) over conventional extrusion methods (4.78%), validating the applicability of the proposed CE assessment framework.