Eleni Gaki (p), Nikolaos-Iason Koufodontis

Charalampos Manousiadis

The Circular Economy has gained significant attention as a sustainable alternative to the traditional linear economic model, which is inefficient in resource utilization and heavily reliant on fossil fuels. This model promotes resource efficiency, waste valorization, and alternative consumption patterns such as renting and leasing instead of ownership. By adopting Circular Economy strategies, economies can become more resilient, competitive, and sustainable.
Integrating Circular Economy principles into regional development is increasingly seen as a pathway to fostering sustainable economic growth. This approach extends product lifecycles, minimizes waste, and encourages the reuse and recycling of materials. Regional authorities and stakeholders are aligning with national and European strategies to implement Circular Economy practices effectively.
At the regional level, transitioning to a Circular Economy requires tailored strategies that address specific local needs while aligning with broader national and European objectives. These strategies must consider regional economic structures and available resources while ensuring coherence with national policies, such as Circular Economy action plans, to maximize their impact.
At the European level, the European Union’s Circular Economy Action Plan (CEAP), launched in 2020, has played a crucial role in guiding regional transitions. It promotes circular practices across industries, waste management, and consumer sectors, encouraging regions to adopt sustainable models that reduce resource consumption and environmental impact.
A key initiative in this context is the Theseus Project, a European effort to establish Greece’s first Hub for Circularity (H4C). Focused on promoting Circular Economy practices in the Attica region and beyond, the project aims to integrate circular principles into regional development strategies. One of its primary tasks is the formulation of Circular Economy action plans that provide strategic frameworks for embedding sustainability into regional policies.
This paper explores the relationship between Circular Economy and regional development by analyzing strategic frameworks in the regions involved in the Theseus Project. It examines their alignment with national and European policies and assesses how effectively they leverage Circular Economy principles to drive sustainable growth. Additionally, it highlights the challenges regions face in harmonizing their strategies with broader policy objectives. By offering an in-depth analysis of these frameworks, this paper provides insights into best practices for implementing Circular Economy strategies at the regional level.

Klio Monokrousou, Argyro Plevri (p)

Charalampos Manousiadis

Implementing and validating a range of real-world water recovery and reuse solutions at a local level provides a strategic opportunity to develop a comprehensive and sustainable water management strategy that is easily scalable and seamlessly integrated into a Regional Master Plan for Circular Water and Wastewater Services. As part of the THESEUS project, a wide array of cutting-edge applications will be deployed across selected areas of the Attica region. These include decentralized solutions such as: (i) sewer mining water reuse technologies aimed at enhancing water availability and improving the resilience of urban parks, (ii) Nature-Based Solutions like rain gardens, bioswale systems and green corridors, and as (iii) rainwater harvesting systems installed on the rooftops of schools and other buildings. In parallel, centralized solutions will be tested, including the use of reclaimed water from a particular wastewater treatment plant (WWTP) for fertigation on agricultural fields, assessing both the potential benefits and risks of this practice. Additionally, sewage sludge from the Psyttallia and Metamorfosis WWTPs will be explored as a feedstock, providing valuable insights into resource recovery and the potential for creating closed-loop systems.

For the successful implementation of these initiatives, it is crucial to involve communities and regional stakeholders in the co-creation and co-decision process, ensuring that knowledge is shared and integrated into policy and planning efforts. These practical on-the-ground solutions are designed to mobilize and engage a diverse group of stakeholders including regional authorities, policymakers and potential end users, fostering collaboration and driving broader support for water management initiatives. Collectively, through a practical and scientifically grounded approach, it is attempted to increase societal resilience, enhance the acceptance of innovative solutions, and contribute to the long-term sustainability of the region.

Marianna Lena Kambanou (p), Murat Mirata

Eleni Gaki

Industrial and Urban Symbiosis (I-US) enables the more efficient and sustainable use of underutilized resources, such as water, energy, residuals, by-products, waste, and infrastructure, through collaboration among local and regional actors. I-US plays a key role in supporting the transition to a circular economy at the regional level. However, successful implementation requires the coordination of diverse stakeholders, such as large industries that traditionally operate in isolation, utility providers, SMEs, technology providers, facilitators, policymakers, research institutions, and emerging business entities that create new value chains.

Given the wide range of actors involved, effective I-US governance models must balance formal governance structures with informal collaboration. Formal governance structures include legally binding contracts between industries, agreements outlining interactions, structured mechanisms for information sharing, the establishment of joint ventures, and the management of shared infrastructure such as buildings, pipes, compressors, waste water processing systems. Meanwhile, informal collaboration through professional networks, trust-based relationships, and knowledge-sharing platforms plays a crucial role in identifying synergies and maintaining long-term partnerships. We find that while informal interactions foster innovation, flexibility, and trust, formal structures provide stability, clarity, and accountability.

By examining case studies of I-US initiatives, this study identifies key formal and informal governance models and explores how they complement each other in facilitating industrial and urban circularity. Findings suggest that while formal governance structures provide regulatory clarity, resource allocation, and risk management, informal collaboration enhances adaptability, stakeholder engagement, and cross-sectoral cooperation. The study highlights the necessity of hybrid governance models that integrate structured approaches with flexible, ad-hoc collaboration to strengthen I-US synergies.

This research contributes to the growing discourse on regional circularity governance by offering insights into the interplay between formal and informal collaboration in I-US. The findings are particularly relevant to regional governments and industrial practitioners seeking to design more inclusive and effective governance strategies that foster I-US synergies in the regional context with the ultimate goal of promoting a circular economy.

Charalampos Manousiadis (p)

Eleni Gaki

Special Session 44 is based on Theseus Project, exploring the necessity of implementing Circular Economy (CE) in a Regional Context. The Theseus Attica Hub4Circularity (H4C) Horizon Europe Project is the first of a kind H4C that will be established in Greece, beginning in Athens. The project aims to close resource loops with innovative urban solutions and achieve climate neutrality by 2050, in line with P4P goals. Theseus will validate and develop water, energy and material technologies based on regional needs, incorporating digital and robotic solutions, under innovative governance models.

CE is implemented at different levels, as the Industrial Symbiosis (IS), focusing on industrial ecosystems and extending into cities via Industrial-Urban Symbiosis (I-US). Another similar concept is Circular Cities and Regions Initiative (CCRI) having the opposite direction, from urban extending into industrial environment. H4C concept emerges as the next evolutionary stage, combining I-US and CCRI, mainly at regional level, proposing systemic solutions, integrating multiple regional stakeholders and introducing a variety of different operational models, due to the different regional settings and sector needs. H4C will be the main vehicle for the Regional Circular Economy (RCE), which expresses the integration of CE practices into the overall sustainable regional development strategy, based on regional science principles, including economic, social and environmental aspects.

Previous work on identifying and facilitating I-US synergies has been conducted, creating matchmaking frameworks using multicriteria methods, mainly focused on waste streams and stakeholders’ compatibility. To support H4C concept, there is a need to align I-US synergies with regional development strategies and relevant regional science methods. A first study of matchmaking for synergies within regional territory is conducted in relevant projects. Theseus will enhance this research, focused on the integration of regional settings, including region’s type, characteristics, strategies, resources availability and wastes, infrastructures, special needs or challenges, called as “Regional Scenery”, into the matchmaking framework. Based on Regional Scenery, a Profile will be formed aiming to 1)Prioritize the proposed synergies based on the magnitude of the material, water, energy flows or services involved (the “size” occupied and the importance of the specific flows and related sectors within the region); and 2)Assess and further prioritize synergies according to their impact (by fine tuning different impact factors to be specialized to the specific region) into the overall sustainability and related strategy of the Region.

Theseus H4C project, related aspects and the regional framework will be presented in this study.