Circularity and efficiency assessment of resource recovery solutions

Abstract

This chapter presents a detailed description of the circularity and efficiency assessment methods to be used in the context of resource recovery solutions in the water sector. The resource recovery solutions are meant to produce multiple benefits, such as increased resource efficiency and decreased negative environmental impact, among others. The solutions need to be assessed and compared using a comprehensive set of criteria and indicators. This report discusses key concepts, explains methods, and briefly presents a spreadsheet tool developed for conducting the assessment. Some key concepts, such as circular bioeconomy and efficiency, are first introduced. Several resources may be recovered from the water sector, and thus, commonly recovered resources are classified. This is followed by an expansion of the scope of the material circularity indicator, a prevalent assessment method. This is done to apply the MCI to the resources relevant to the water sector. Equations for the resource categories are developed and presented. Efficiency is then defined as a ratio between the benefits and costs of a resource recovery solution. Two categories of cost indicators are introduced, followed by three categories of benefit indicators. By combining different cost and benefit indicators, several indicators such as simple material efficiency, service unit-based energy efficiency, and service unit ecoefficiency can be created. Circularity and efficiency assessment methods are explained with simple examples, and screenshots from the spreadsheet assessment tool are presented. Lastly, the assessment method is demonstrated on a real-life case study located in Italy. The case study involves reuse of treated wastewater (TW) for irrigation. The newly developed circularity and efficiency methods demonstrate the improvements in the circularity and efficiency resulting from TW irrigation reuse, along with pointing to the most crucial factors to be considered for such cases.