Urban Circular Economy Research Articles

Methodological framework for the implementation of circular economy in urban systems

Urban areas are hubs for innovation, economic activity and growth that hugely influence the development of our society, making those areas important drivers in the global transition towards circular economy. Although global policies are necessary to set the general ambition, local interventions are crucial to realize it. This paper presents a methodological framework aimed at facilitating the understanding and application of circular economy strategies in urban systems, that being a single city, or urban regions. The framework is conceived as a flexible structure that contains a network of potential decisions, describing different convergence and divergence points, and that is meant as a supporting tool for future urban circular economy implementation initiatives.After a literature review and an analysis of specific case studies on urban circular economy implementation, a four-phased methodology is proposed where the territory is explored in order to identify and select initiatives in the areas with greatest potential for circular economy. Actions needed to implement the selected initiatives are finally summarized in a roadmap. Each phase contains recommendations of different tasks to complete and available tools for achieving the expected results. Different approaches to adopt in the application of this methodology are discussed as well, such as production-based vs. consumption-based, and top-down vs. bottom-up. Special emphasis is put on the importance of involving local agents, in order to obtain specific and validated proposals that are adapted to the reality of the territory and the concerns of the stakeholders.Through these comprehensive guidelines, the ultimate goal of this methodology is to help urban systems to foster circular economy principles, and therefore reaffirm their role in addressing and managing global sustainability issues.

Matera: city of nature, city of culture, city of regeneration. Towards a landscape-based and culture-based urban circular economy

Each city is a living organism with its own dynamics. Cities, as complex dynamic and adaptive systems, are able of self-organization/self-management. There are many causes of the decline of cities today (poverty, unemployment, etc.) that interdepend on the others in continuous retroactive processes. The general proposal of this paper refers to a key word: “regeneration” as revitalization of the activities in the perspective of the circular economy/city. The aim is to explore how an urban circular economy can be implemented through a cultural landscape-based approach, analysing the case study of Matera (Italy) and assuming the interdependence between a specific landscape and the circular economy/city models. The aim is to understand how to transform a millennial experience of underdevelopment into a dynamic development perspective.

Development of an urban FEW nexus online analyzer to support urban circular economy strategy planning

Growth of urban population around the world and, particularly, within urban areas, has placed various pressing challenges on Food, Energy, and Water (FEW) such as food security, water safety as well as energy scarcity and so on. Current studies on urban FEW nexus are mainly focused on the correlation analysis of elements by pairs, while these works are developed separately. With respect to the methods, the existing researches mostly adopt the bottom-up approach, accounting for the direct relationship between the individual production sectors. While the associations between the internal elements of the system still lack of simulation. In this study, we aim at developing an online open access tool for cities, the Urban Circular Economy Calculator (UCEC), which enables to develop different circular economy scenarios associated to FEW management. UCEC v1.0 uses Beijing data as test case. In particular, more than 20 circular economy policies related on food, energy and water are selected and divided into 6 categories. Long-term simulations on the social, economic and environmental impacts are provided to test the trajectories of policy effects. Being an open access tool, UCEC can be used also for supporting participatory processes as an urban management instrument. The solution is economically and financially feasible, due to the low level of technical requirements. The necessity of such a tool is proved by the societal need of transition toward a low-carbon and sustainable framework, which can be effectively supported by the introduction of circular economy. This transition, such as the idea behind UCEC, should preserve (or even improve) the societal wellbeing, while increasing basic resources (i.e.: FEW) accessibility, security and preservation.

Production of energy (biodiesel) and recovery of materials (biochar) from pyrolysis of urban waste sludge

Safe disposal of sewage sludge is one of the most pressing issues in the wastewater treatment cycle: at the European Union level, sludge production is expected to reach 13 Mt by year 2020. Sludge disposal costs may constitute up to, and sometimes above, 50% of the total cost of operation of a WWTP, and contribute to over 40% of its GHGs emissions. The most common disposal options at the moment are landfilling, disposal in agriculture (about 40% EU-wide), incineration or co-incineration, and use in the industrial production of bricks, asphalts and concrete. Sewage sludge, however, still contains beneficial resources such as nutrients, that can be recovered through specific processes (e.g. precipitation as struvite) and energy, recoverable through a variety of approaches. Microwave-assisted pyrolysis of urban waste sludge was applied for the production of oil, (Syn)gas, and biochar that were afterwards characterized and compared to mainstream alternative fuels (biodiesels) and other material recovery options. Sustainability issues related to the production of biodiesel/biochars from urban wastewater treatment sludge are also discussed. The paper shows that waste urban sludge can indeed be a full component of the urban circular economy by allowing, if properly processed, recovery of energy resources at multiple levels: bio-oils (biodiesel), syngas and bio-char, all having definite advantages for final residues use and disposal. Biodiesel, in particular, allowing energy recovery as liquid fuel, offers a much more flexible and efficient utilization.

Evaluation of Urban circular economy development: An empirical research of 40 cities in China

Abstract The city is an important component in the construction of circular economy (CE), and after years of development, assessment of urban CE and calculation of an urban circular development index (UCDI) is an important task that the Chinese government has faced. However, existing research into the indicator system and evaluation methods is not enough to support calculation and subsequent publishing of UCDI. Building off current research into CE, its index systems and its evaluation, this paper puts forward an evaluation index system for urban CE development (UCDI) that uses an improved entropy methodology combining expert and entropy weightings. The index was calculated for 40 cities that were part of China's pilot CE cities program for alternating years in the five year period between 2012 and 2016 (that is, the index was calculated for 2012, 2014 and 2016). The study found that the level of urban CE increased significantly over the five year period, with that in the CE pilot cities growing at a faster rate than the national average. Results show that a certain relationship exists between UCDI, urban types and economic development, but has little relationship with industrial structure. Finally, recommendations for the promotion of urban CE are proposed.

Carbon footprints of urban transition: Tracking circular economy promotions in Guiyang, China

Promoting urban transition is critical, particularly for China’s rapid urbanization. Circular economy strategy is widely recognized as an effective way to achieve a low-carbon transition of cities through improved waste recycling and industrial symbiosis. However, the evidence of low-carbon benefit is less reported. While the carbon footprint (CFP) represents a mature tool responding to climate change concerns, limited studies have made use of CFP as a proxy for the performance of urban circular economy promotion. The aim of this paper is to investigate the CFP with a ten years span (2002–2012) of Guiyang, so as to understand how its circular economy practices have led to low-carbon benefits. Guiyang, one of China’s national pilots of the Circular Economy (CE) City, the Low-Carbon City, as well as the Ecological Civilization City, has offered an ideal laboratory where the opportunities and challenges for a low-carbon urban transition can be explicitly discussed. A hybrid model that integrates an input-output (IO) approach and process-based inventory analysis is developed to distinguish between direct carbon emissions of sectors from energy consumption, and indirect carbon emissions related to upstream and downstream flows both from production and consumption perspectives. The CFP of Guiyang in 2002, 2007 (after becoming the circular economy pilot) and 2012 (with implementation of urban industrial symbiosis) are analyzed by taking the 2002 as year of business as usual (BAU) scenario. Particularly, we identify scenarios related to proposed urban industrial symbiosis. Results imply that dramatic resource saving and CFP reductions could be achieved simultaneously. Changes to the CFP in 2002, 2007 and 2012 provide critical insights into the role of circular economy in speeding up urban transition towards a low-carbon society. Finally, policy recommendations to tackle the barriers to regional low-carbon transition are proposed. We believe that this study is informative for policy makers of urban planning by shedding a light on innovative eco-industrial development and urban transition in China.

Innovation Research on Operation Mechanism of Urban Circular Economy in "Blue and Yellow" Economic Zone in Shandong Peninsula

Innovation on the system of urban circular economy is effective way to realize the economic form of ecological civilization and carry out the scientific development. The development of urban circular economy in "blue and yellow" economic zone in Shandong peninsula needs innovation of operation mechanism. In this paper, based on the analysis of the main body, the system and operation process of urban circular economy, the writer researched the operation mechanism of urban circular economy in "blue and yellow" economic zone in Shandong peninsula and proposed the driving mechanism, control mechanism, security mechanism and overall arrangement mechanism of urban circular economy operation.