How do circular and low-carbon cities influence the future of waste management? An ISWA initiative aims to develop a calculating tool based on the example of the Dutch city of Rotterdam. What can we learn from the example of the gateway to Europe?

Rotterdam, Europe’s largest harbor city and the home of the General Secretariat of ISWA, has both the pain and the privilege of being the first experimental early-adopter city in the Circular and Low Carbon Cities (CALC) project. This project, commissioned by the ISWA Scientific and Technical Committee (STC), seeks to break the business sector’s monopoly on evidence-based circularity with its focus on cities. CALC has the ambitious goals of convening and facilitating a network of circular cities, and working with them to develop and test circularity metrics. The project is now entering its second year.

Focus on the way materials flow through cities

CALC focuses on real-time circular processes in cities and thus differs from many other circularity initiatives, ranging from the Ellen MacArthur Foundation’s Circulytics to the work of the International Resources Panel, which primarily focuses on materials and design. In CALC, the basic idea is that processes are actionable: a focus on circular processes such as repair, re-use, re-purposing, renovation, or rental provides cities with information to inform policy and practice and facilitates transparent change.

ISWA, the International Solid Waste Association, is supporting the transition to a circular economy and is encouraging its members and their national and regional governments to move to a circular economy. With its diverse base of members from waste management, academia, and the production sector, ISWA is well placed to initiate such a project and also to put its own spin on the task of creating evidence-based metrics on circularity.

Thus, while other circularity initiatives push for changes in design and material choice and packaging and distribution, which give feedback to stakeholders in production, logistics, and consumption, CALC’s metrics are by, for, and about cities, and specifically for complex cities and/or urban regions in high-income countries and emerging economies.

In the CALC network, the Porto region of Portugal exchanges ideas with Rotterdam and Vitoria-Gasteiz (Spain), Vienna and Milan talk about their issues with textiles, and European cities such as Helsinki and Oslo discuss bio-waste with Keene, New Hampshire (USA). Additional cities are invited to join these and other cities, which have participated in the CALC network since mid-2020.

How circular is a city?

In its first year, 2020, CALC’s 20-person volunteer project team focused on developing concrete, evidence-based metrics on city circularity. The first metric is availability, that is, the presence of circular processes in a city. Data gathering is simple: count the premises where circular processes are located.

The second metric is intensity, that is, how much material is actually flowing through these circular processes. This can be calculated based on kilograms or on items, or on a combination. The third metric is impacted. Technical University of Munich student Kartik Kapoor has been developing this metric as part of his MSc thesis. The impact is expressed in tonnes of CO2-equivalent saved through the use of circular processes compared to those products or materials going to disposal or recovery.

Co2 impacts of circularity

There is broad agreement that the circular economy is a good thing, but what is its actual impact? CALC emphasizes the potential already present in cities to extend the useful life of products and processes and focuses on decisions made by the city, its citizens, its markets, and its contractors on whether to refuse (to buy new) to repair, re-sell, refurbish, or the like. To do so, a CO2 or greenhouse gas (GHG) calculator is needed to compare scenarios.

CALC team members assessed the CO2 calculators available and decided that the USEPA WARM Model offers the best basis for metrics that illustrate the impacts of circular processes in complex cities. WARM is process-focused and a scenario-based decision support model. One drawback is that, in its current form, WARM is based on North American defaults for transport and other energy-intensive processes, which can be addressed by either changing the reference databases in the “background” or producing a new set of background life cycle assessment (LCA) databases.

Rotterdam: Complex city

Rotterdam city government has existing policy priorities in relation both to the circular economy – the city is to be 100% circular by 2050 – and to reducing carbon emissions – the city has agreed to become climate-neutral by 2050. Daan van den Elzen, Rotterdam’s waste management representative and chair of ISWA’s Young Professionals Group (YPG), states that “the circular economy and climate ambitions have been operating on different policy islands which, if they worked together, could make more substantiated policy decisions regarding both goals.” Rotterdam looked back into the chain of products and waste streams in order to understand wherein the process of a product most CO2 emissions are being emitted. Understanding that most emissions take place in the resource extraction and production phases was an eye-opener since many climate and circularity initiatives only focus on changing the fuel to more sustainable alternatives, but more or less continue with the same processes. “CALC caused this mindset to shift, which is important for a city municipality in which different departments compete for the same limited budgets. By forming decisions on evidence-based metrics, more objective and impactful decisions can be made on where resources should flow.”

For CALC, 2021 will see the release and beta-testing of a data portal – integrated with the Sustainable Development Goals on waste management and recycling – that enables cities to enter their data, reconcile it with international composition categories, score their circularity, and calculate their CO2 reduction from intensifying and facilitating waste prevention, recovery and recycling activities. Thus any CALC city can also report to UNEP and UN-Habitat on their progress towards sustainable materials and waste management.

The Project: Circular and low carbon cities (CALC)

A joint initiative of the ISWA Working Groups on Recycling and Waste Minimisation, Climate Change and Waste Management, Biological Treatment of Waste, and Communication and Social Issues.

The goal of the project is to research, develop, test, and support the basic metrics of circularity and low-carbon cities through the elaboration of an open-access tool, in the form of a calculator, for cities and regions. The purpose of the tool is to provide quantitative, transparent, comparable, and practical points of measurement for cities using the tool as an input for decision-making about materials management on a city-wide basis. The calculator is designed to empower cities to understand

how their materials management systems “perform” in terms of circularity and CO2 emissions, how the processes in the city promote or degrade sustainable resource use, and what kinds of interventions – in the city or in the value chains of the materials flowing through the city – could bring about an improvement.

The project will focus not on modifying the behavior of individuals, but on changing operations at the systems level so that the “new normal” of current and future materials management systems promote a longer useful life of products and materials, more and higher-value recovery, cleaner streets and parks, and lower levels of disposal. For this to happen, all the incentives need to line up so that users of the system follow an easy path that leads to low-carbon and circular management of products and materials that are discarded.

The project team has agreed on a “shortlist” of focus products and more general materials streams as the basis to develop and test the methodology. These have been selected based on the priorities of Rotterdam. For other cities, the recommendation would be to choose at least three of the following materials or streams: textiles (shoes or children’s clothing), organics: GFE (vegetables, fruit, plate, and preparatory food waste) plus bread, distribution packaging (pallets), WEEE (one specific kitchen appliance such as coffee-makers or refrigerators), and construction and demolition materials (plywood and related composite wood materials, both in construction and in demolition).