Measurement and assessment of circular economy in water systems

Abstract

As the concept of Circular Economy (CE) is gaining momentum, the need for appropriate circularity assessment methodologies and indicators grows exponentially. Although circularity in water requires a nexus approach according to the new Circular Economy Action Plan, a sectoral division is still dominated in the scientific community. In this study, a thorough appraisal of the latest literature is conducted, providing an overview of existing tools, methodologies and indicators that have been used to assess water systems considering the need of assessing both anthropogenic and natural elements. The identified lack of a holistic methodology and comprehensive indicators assessing complete water systems from a circularity perspective led to the development of a circularity assessment framework, namely the Multi-Sectoral Water Circularity Assessment (MSWCA) framework. The MSWCA follows a multi-sectoral systems approach, symbiotically managing key socio-economic and non-economic sectors of the Water-Energy-Food-Ecosystems nexus. The developed framework enables the investigation of the feedback loops between the nature-managed and human-managed systems to assess water and water-related resources circularity and develops an indicators database facilitating the assessment. This study further develops a novel approach that combines both expert and participatory practices for the prioritization of indicators based on views and needs of practitioners, whilst considering the complex interdependencies of the indicators and determining their importance. The 20 circularity indicators of the MSWCA framework are ranked by different stakeholders and their interrelationships are identified using the Interpretive Structural Model, resulting in 6 levels of importance. Cross-impact matrix multiplication applied to classification (MICMAC) analysis further enabled the classification of the indicators into 4 categories based on their driving and dependence power. Finally, following the MSWCA framework, a dynamic indicators-based modelling tool is developed and applied to the HYDROUSA H2020 project. Benchmark and dynamic circularity assessments are performed to compare the circularity performance of the HYDRO system to the previous configuration of the system and to optimize HYDRO system’s operation by investigating changes in circularity performance of different operational scenarios, respectively. The circularity performance of the system is based on the results of 46 operational indicators that target system’s multi-functionality and additional benefits and costs, all incorporated resources, waste and emissions, as well as economic, technical and ecological aspects, the 3 CE principles and are related to 13 SDGs.