Category: News

On 11 August, the first stakeholder workshop was organised by our Polish project partners ECOL UNICON, the company responsible for the the demo site in Gdansk and RetencjaPL, which is responsible for developing the decision-support tool for water policy within the DECIRE-WATER project. The workshop provided a platform for discussing the future of rainwater and greywater recovery systems in Poland, with a particular focus on the technologies being tested at demo site 3. These include the treatment and reuse of greywater for toilet flushing, as well as the purification of rainwater for everyday non-potable applications such as washing, cleaning, and laundry.

This first online workshop aimed to initiate actions towards reshaping the implementation of these water and wastewater recovery systems across all stages of the process, from obtaining the necessary permits, through ensuring user safety, to developing clear and coherent regulatory frameworks.

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Fourteen stakeholders attended this online workshop, representing a wide range of organisations, such as municipal water supply companies, city councils, sustainable building certification auditors and systems designers. Among the participants were also representatives of the Polish Water Chamber and the Polish Green Building Council (PLGBC).

The diversity of the participants enabled a rich, multi-perspective discussion, with each stakeholder contributing insights from their respective sector. This exchange helped identify challenges and opportunities that are often overlooked when viewed from a single organisational perspective. To facilitate the discussions, the workshop employed the World Café method, which was adapted for an online format. This approach enabled stakeholders from outside Gdańsk to participate while supporting wider engagement with the DECIRE-WATER project. Through the use of breakout sessions and interactive Mentimeter boards, participants were able to share their ideas openly and engage in focused discussions within smaller groups.

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The discussions were highly engaging, with participants actively contributing throughout the session, and focusing on the following key topics:

• Legal and regulatory aspects
• Economic challenges and opportunities
• Integration of water recovery systems within urban infrastructure
• Social acceptance and user safety
• Cross-sector collaboration

A key conclusion was that the lack of clear and consistent regulations remains one of the main barriers to the wider adoption of water recovery systems in Poland. This challenge is particularly evident in public buildings, where ensuring user safety and maintaining a high level of system reliability are essential requirements.

Participants also highlighted the financial aspects of implementing water and wastewater reuse systems. While the initial investment can be significant, it was noted that growing demand for such solutions could lead to the introduction of dedicated funding schemes and financial incentives in the future, helping to improve their economic viability.

The role of local authorities in promoting more sustainable water use was another important topic of discussion. Participants pointed out that municipalities already have the capacity to introduce measures aimed at conserving drinking water. For example, restrictions can be imposed on the use of tap water for garden irrigation during periods of drought. However, stakeholders agreed that broader uptake of water recovery technologies will require action at the national level. Clear regulatory frameworks and technical guidelines are needed to provide certainty for designers, investors, and end users, and to encourage greater interest and confidence in these solutions.

Participants also highlighted the importance of public awareness campaigns and educational initiatives in fostering understanding and acceptance of innovative water recovery technologies. Raising public awareness is particularly important in the context of wastewater reuse, where concerns about safety and the use of treated water remain widespread. Participants emphasised that clear communication about treatment processes, water quality standards, and the benefits of water reuse is essential for building public trust and encouraging the adoption of these solutions.

The workshop provided valuable insights into the practical needs and challenges faced by professionals working in the water sector. It enabled the identification of areas requiring clarification regarding regulations, and confirmed that water recovery technologies have the potential for large-scale implementation. The meeting also strengthened cooperation among institutions involved in water management across Poland.

The next steps include incorporating the findings into the work on the decision-support tool being developed by RetencjaPL and further consultations with the industry to optimise the demonstrated system in Poland, particularly in terms of costs related to energy consumption.

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Author: G. Pawelkiewicz

The DECIRE-WATER team in Greece has successfully completed the construction of Demo Site 1 on Lesvos Island, marking an important milestone in advancing sustainable water management in tourism-dependent regions.

Designed by the Laboratory of Water and Air Quality at the University of the Aegean, the demonstration site showcases an innovative decentralized greywater treatment and reuse system that combines nature-based solutions with a compact engineering design. Installed at the Delfinia Hotel in Molyvos, the system demonstrates how treated greywater from kitchen sinks and dishwasher facilities can serve as a valuable alternative water resource for non-potable applications, reducing freshwater consumption while supporting the transition to a circular water economy.

Mediterranean islands experience increasing pressure on freshwater resources, particularly during the summer tourist season, when water demand rises dramatically. Hotels located outside centralized wastewater infrastructure often rely entirely on potable water for non-potable applications, such as irrigation and toilet flushing. At the same time, large volumes of greywater remain an underutilized resource. Demo Site 1 addresses this challenge by demonstrating a decentralized treatment and reuse system that recovers greywater and produces Class B reclaimed water in accordance with the principles of the European Water Reuse Regulation (EU) 2020/741.

The pilot installation was integrated within the premises of the Delfinia Hotel, allowing the system to operate under realistic conditions while minimizing interference with the hotel’s daily activities. The construction of the system included the complete installation of the treatment train, beginning with the collection and pre-treatment of greywater. Wastewater from kitchen sinks and dishwasher facilities is first conveyed through a grease interceptor and stored in a collection tank.

The greywater then passes through a coarse filtration unit before entering the constructed wetlands. During these preliminary treatment stages, fats, oils, and large suspended solids that could interfere with downstream treatment processes are removed. This initial treatment stage protects the biological treatment units from clogging and contributes to the long-term operational stability of the system.

The core of the installation consists of four pallet tanks arranged in parallel, operating as a vertical unsaturated subsurface-flow constructed wetland with a total treatment surface area of approximately 5 m². The wetland was engineered to operate under intensified hydraulic loading conditions while maintaining high treatment performance. Carefully designed hydraulic distribution, substrate layers, and drainage components ensure the uniform distribution of wastewater throughout the bed, promoting efficient biological degradation, filtration, and natural purification processes.

The system also supports ornamental climbing plants, creating an attractive green façade that integrates greywater treatment into the surrounding hotel environment while enhancing green space, promoting biodiversity, and improving thermal comfort.
Downstream of the constructed wetland, a chlorination unit was installed to ensure the microbiological safety of the treated effluent prior to storage and reuse. In addition, storage tanks, pumping equipment, and hydraulic control systems were installed to enable the storage, recirculation, and controlled distribution of the reclaimed water.

With construction now complete, Demo Site 1 is fully prepared for the operational and monitoring phase of the DECIRE-WATER project. The system will be evaluated for its ability to remove conventional pollutants, organic micropollutants (benzotriazoles and benzothiazoles), and pathogens, while assessing the long-term performance of this compact nature-based treatment technology in tourism facilities.

Beyond its scientific objectives, the demonstration highlights how decentralized water reuse systems can help hotels reduce freshwater demand, strengthen climate resilience, and contribute to more sustainable tourism across Mediterranean islands. The experience gained at the Lesvos demonstration site is expected to support the wider adoption of circular water reuse solutions in water-stressed tourist destinations throughout Europe.

Author: I. Priovolos
Images: I. Priovolos, E. Stefanatou

On 17 June 2026, the first DECIRE-WATER stakeholder workshop was held in the EcoSUN Village in Ndlambe Municipality, Kenton-on-Sea, South Africa. It brought together the local community, researchers, public authorities and water-sector representatives to help shape the project’s South African demonstration site.

Co-design and co-creation are central to developing the waste water treatment solutions offered through the demo sites of the DECIRE-WATER project. Rather than introducing a predefined technical solution, the project aims to involve the people and institutions affected by it – from the planning stage onwards. This approach helps to ensure that decentralised water solutions respond not only to technical requirements, but also to local social, economic and cultural conditions and needs, while strengthening trust and local ownership. Stakeholder participation is a core part of the project´s methodology and its pathway towards wider acceptance and uptake of decentralised water solutions.

The workshop gathered a total of 46 participants and was jointly organised by the project partners Nelson Mandela University (NMU), RPTU Kaiserslautern-Landau and VDI/VDE Innovation + Technik GmbH. The participants represented four main stakeholder groups, such as local and national government, water-sector institutions, researchers from Nelson Mandela University and RPTU and the local community.
Among them were representatives of the Eastern Cape Department of cooperative governance and traditional affairs (ECOGTA), members of the Departement of science, technology and Innovation (DSTI), the director of the department of water and sanitation (DWS) and several members of the Local Ndlambe Municipality. Various institutions were well represented, but the local perspectives were at the centre of the discussions as participation of the community was particularly strong.

The workshop began with welcoming remarks from representatives of Ndlambe Municipality, followed by a round of introductions among all participants. The Deputy Director of Ndlambe Municipality then led a tour of the EcoSUN Village, providing participants with an overview of the site and its local context. Following the tour, RPTU introduced the evapotranspiration tank (TEvap) system planned for implementation at the community and presented its main principles and intended application within the project.

The TEvap is a nature-based, decentralised system for the treatment of household blackwater. Building on experience with TEvap systems in Brazil, DECIRE-WATER will further develop the concept for South African conditions, working towards a modular and scalable solution using locally appropriate materials and adapted design and operation.

Following this presentation, the World Café methodology and workshop structure were introduced by VDI/VDE. Participants were informed about the discussion format, the rotation between thematic groups, and the role of each session in gathering perspectives and inputs from the different stakeholder groups.
The discussions in the groups crystalized around the following topics:
technology, public perception, governance and regulation, business opportunities.

The participatory format encouraged open exchange between participants with diverse backgrounds and with different levels of technical experience.  Discussions were adapted to the local context, with all key information translated to IsiXhosa, the main spoken local language. This created opportunities for participants to communicate and explain their concerns and expectations in their own terms, resulting in inclusive and lively discussions.

Throughout the entire workshop, the atmosphere was lively and constructive. A recurring message from community participants was the wish to be active partners in the process rather than only recipients of a new technology. Participants highlighted the importance of local training, the involvement of local workers and suppliers, clear communication, and continued engagement throughout implementation and further operations. At the same time, discussions openly addressed practical challenges such as operation, maintenance, responsibilities and long-term sustainability. These priorities reflect DECIRE-WATER’s broader objective of involving stakeholders directly in planning, co-design and implementation.

Furthermore, the workshop provided valuable input for adapting the TEvap demonstration to local needs and helped to identify priorities for the next implementation steps. Technology training led by NMU and RPTU will follow, while the workshop outcomes will feed directly into the detailed design, construction and future monitoring of the demonstration site.

Next steps in the stakeholder participation process will be a collection of direct feedback after construction and during operation followed by a second stakeholder workshop toward the later end of the DECIRE-WATER project to discern and discuss challenges, requirements and possibly responsibilities for sustainable long-term operations and possible scale-up and blueprinting.

Author: V. Ly Lito Pinto

Over the last few months, project partners RPTU University of Kaiserslautern-Landau, AKUT, Stadtentwässerung Stuttgart (SES) and University of Innsbruck (UIBK) have successfully established DECIRE-WATER’s Demo Site 5 in Stuttgart, Germany.
Marking a major milestone for the project, the system has been fully constructed, connected, and officially started up by mid-2026.

This demo setup is the direct result of the close collaboration among two academic institutions (RPTU and UIBK), the engineering and planning firm AKUT, as well as the local wastewater utility in Stuttgart, SES. Together, the partners orchestrated the planning, design, and implementation phases, successfully transitioning the system from a conceptual design into an operational, hybrid technical/nature-based reality.

As climate change accelerates, urban areas face prolonged periods of droughts, driving an urgent need for sustainable, climate-resilient water management solutions.
Our demo site in Germany addresses these critical challenges by demonstrating how modular solutions can treat sewer wastewater (“sewer mining”) for local irrigation reuse.

This demonstration site features different mechanical pretreatments, novel constructed wetlands for wastewater treatment, and a disinfection system, playing a critical role in achieving DECIRE-WATER’s broader objective: proving that decentralised solutions can secure urban water resources while integrating into existing centralised wastewater infrastructure.

The past few months have seen intense activity on-site to bring the hybrid technical/nature-based demo site to life. Key activities included setting up three different pretreatment units, laying over 200 meters of piping, and filling two constructed wetland compartments with novel filter media. Additionally, the team installed the UV disinfection system, the control and automation unit, a rainwater cistern, and ivy facades alongside an automated irrigation.

Following the technical installation, both constructed wetlands were planted with Phragmites australis (common reed) that drive the natural filtration processes. The team achieved then the “wet start-up,” introducing water into the system for the first time to test hydraulic routing, flow rates, and connection integrity.

Following the successful wet start-up, the system is now operational. The vegetation is currently acclimating, the filter media is settling, and the vital microbiological processes are establishing.

Next, the partners will begin routine monitoring as mechanically pretreated wastewater is introduced. RPTU will track system performance and investigate different operational strategies to ensure safe water reuse, focusing, among others, on the removal of pathogens, antibiotic resistance genes, and organic pollutants. These findings will provide relevant data to drive the implementation of decentralised water reuse strategies across the European Union and elsewhere.

Author: C. Morandi
Images: S. Bauschatz

The Can Cabanyes constructed wetland operates as a pioneering hybrid water reuse system that integrates a 1-hectare surface flow constructed wetland with a mechanical reclamation plant. This nature-based solution (NBS) is designed to polish secondary effluent from the nearby Granollers Wastewater Treatment Plant (WWTP), operated by Consorci Besòs Tordera. The system currently produces over 10,000 m³ of reclaimed water annually. A key feature is its 8.5 km non-potable distribution network, which currently supplies around half of the water needed for both urban green space irrigation and street and sewerage maintenance.

History
The system was put into operation in 2003, marking the beginning of a transformation of what was then a highly degraded peri-urban ecosystem near the Congost River. Before its restoration, the site was heavily impacted by industrial infrastructure, a highway, and an old landfill. The initial project required a comprehensive restoration plan that included closing the landfill, recovering river banks, and reclaiming pedestrian paths to create the current public park.

Main transformation phases:

2002-2003: Sealing the wetland basin with local soil compaction and planting high-density vegetation, such as Phragmites australis and Typha latifolia.

2004-2005: Facing ecosystem stabilization issues, where phytoplankton and zooplankton “blooms” caused temporary spikes in organic matter and suspended solids.

2008: Addition of a mechanical reclamation plant featuring disc filters and chlorine disinfection to meet stricter water quality standards for water reuse

The system matured over two decades with the successful integration of nature-based solutions and mechanical treatment that created the stable hybrid foundation used today.

Achievements
Can Cabanyes has proven that hybrid nature-based solutions are both reliable and highly efficient for urban water reuse. The system consistently meets the water quality standards set by the regional authority for key parameters, including pH, total suspended solids (TSS), and pathogens like E. coli, Legionella, and nematode eggs.

From an environmental and social perspective, the site has successfully transitioned from a degraded industrial area into a high-value peri-urban park integrated into the Natura 2000 network. It now serves as a vital ecological corridor, hosting species of special interest like the Mediterranean turtle (Mauremys leprosa) and a diverse range of bird populations.

DECIRE-WATER activities
Now in 2026 the site is undergoing a major expansion set for completion by 2027, which includes a flooded forest, a second tertiary wetland and a bioremediation stream to showcase the potential scalability of reclaimed water for agricultural and urban uses.

As a “lighthouse” demo site for the project, Can Cabanyes is pioneering the use of advanced real-time E. coli sensors to ensure the safe expansion of reclaimed water for agricultural and urban uses.

The primary goal is to develop an in-situ, real-time monitoring system capable of detecting fluctuations in water quality and providing early warnings of fecal contamination spikes. The sensing approach combines DNA-based (total bacteria) and RNA-based (specific bacterial targets) staining with flow cytometry and advanced data analysis.

Author: E. Gonzalez Flo

On 3 February, the DECIRE-WATER consortium met virtually for its first progress meeting, also providing a good opportunity to welcome new team members and PhD students who have recently joined the project.

Since the kick-off meeting in July last year, the work packages have established their regular coordination meetings, and several teams have been formed to address cross-cutting issues such as communication/dissemination and data management.

As activities for 2026 have only recently begun, the main objective of this meeting was to ensure that all partners were aligned. During this three-hour meeting, the work package and task leaders shared updates on the progress of their work, current challenges, and next steps. Planning of all demo sites is complete, with operation set to begin between May and June 2026.

All partners are looking forward to the next physical consortium meeting, which will be hosted by our partner Universitat Politècnica de Catalunya (UPC) in Spain in October.

On July 2nd and 3rd, we officially launched our EU-funded project dedicated to advancing sustainable and climate-resilient water management. The meeting was hosted by administrative Coordinator Karlsruhe Institute of Technology (KIT) and brought the consortium together for the first time.

The fifteen partners from research, industry, environmental services, and public administration aligned on project goals, organizational structure, and next steps to ensure effective collaboration. Besides the European partners, a delegation of the South African team from partner Nelson Mandela University (NMU) travelled all the way to Karlsruhe to participate during the two days meeting.

Key Highlights from the Meeting

• Presentation of project objectives and work packages
• Overview of governance, communication, and coordination strategies
• Inspiring exchange among consortium members
• Initial steps toward pilot regions and stakeholder engagement

Looking Ahead

With a strong consortium and a shared vision, we are excited to shape the future of water governance in Europe and beyond. DECIRE-WATER represents a significant step toward closing water cycles, reducing environmental impact, and building resilience against climate-related risks.