Approaches to monitoring and evaluation of resource recovery from waste towards a circular economy

Introduction

Solid waste, the materials, components, and products generated and/or produced by human and animal activities and discarded when they are no longer wanted or have any use, is the aftermath of an increased consumption of resources. Economic growth and technological advancements have given rise to a great variety of materials, components, and products, offering access to goods and services to a large part ot the ever-growing global population. This has the unintended consequence of using natural resources at a faster rate than regeneration, while finite resources are severely depleted. In addition, materials, components, and products are often designed to have shorter lifespans, for example, single-use and disposable products, while others are selected or tailor-made to fit the needs of the specific area or aesthetic qualities (e.g., construction components, food), screening out numerous others that are perfectly functional and/ or edible (Facchini et al., 2018).

Overuse, misuse, and depletion of natural resources and of the materials, components, and products made of them has escalated the issues associated with solid waste generation and management, with waste pollution becoming the new ‘tragedy of the commons’ (Hardin, 1968). Wastes that are not properly collected and managed remain in the environment, and now, large amounts of them are ubiquitously present in all environmental compartments — soil, air, and marine and fresh waters, as well as in biota across the world, causing detrimental effects on the environment, human health, and wildlife. At the same time, more natural resources are needed to make the same or similar materials, components, and products to meet the needs of the global population, leading to a vast dissipation of valuable resources both upstream and downstream of the point where waste is generated in the value chain. In view of these shortcomings, a number of strategies have been formulated to achieve or maintain sustainability in resource recovery from waste. These involve improving recycling rates, banning single-use materials, promoting prevention, and stimulating innovation in the development of alternative materials, components, and products or developing technologies for dealing with them when they become wastes (lacovidou et al., 2017a).

The challenge involved with the implementation of such strategies is that they have reinforced siloed thinking, for example, leading to sector-specific activities for tackling issues at a specific stage in the value chain or influencing a certain group of stakeholders, neglecting to account for the multidimensional implications arising from them. Realisation of the flaws in these strategies has led to the development of the all-embracing concept of the circular economy (CE) (European Commission, 2015), where materials, components, and products behave as either ‘technical or biological nutrients' that can be returned to the economy via circular loops (McDonough et al., 2003; Ellen MacArthur Foundation, 2014). The CE concept places specific emphasis on the importance of limiting waste generation and instead promoting the remanufacture, repair, reuse, recycling, and recovery of waste resources via, and to, different processes, depending on the remaining properties and characteristics of the materials, components, and products.

Notwithstanding the importance of the CE concept, numerous authors have raised concerns that often the circularity of resources and wastes can be insufficient for achieving sustainability in the system and in a way that reduces reliance on, and consumption of, natural resources (Cullen, 2017; Zink and Geyer, 2017). This is owing to the fact that circularity focuses on partial improvements in the system rather than promoting the sustainable management of resources (Geyer et al., 2016). This has implications in achieving the CE, and it is now advocated that effective management of resources through the concept of CE must be linked to an effective monitoring and evaluation process that measures both the feasibility of closing the material component and product loops and the sustainability of doing so (lacovidou et al., 2020).

There is no ‘one size fits all’ method of monitoring the diverse mixture of resources and wastes across a range of environmental compartments. It is therefore important to determine exactly why the monitoring is being undertaken, for example, to track the flow of resources and assess environmental impacts; to determine critical thresholds and targets; to identify potential sources, stocks, and transformation mechanisms; or to measure the effectiveness of policy or other implemented measures. Moreover, it is critical to evaluate progress based not only on environmental and economic aspects, as is usually the case, but also based on social, technical, and political considerations. Compiling information from a range of literature, this chapter will outline and discuss the monitoring and evaluation methods proposed for measuring progress in achieving the CE. It will place focus on the implementation of these approaches at various levels and highlight the gaps in governing circularity effectively and, most importantly, sustainably.