Cases and problemowners
BlueGreen Innovation Challenge 2025
Case 1
Bioelectrodes and blue outreach – future nature restoration in the harbor (Bioelektroder og blå formidling – fremtidens naturgenopretning i havnen)
Horsens Harbor, with its promenade areas, holds great potential to become a model for blue urban development where technology, marine biology, and public engagement come together. Today, the harbor’s aquatic environment is burdened by nutrients, pollutants, and poor oxygen conditions, resulting in murky water and low biodiversity. The water quality currently limits the ability to use the harborfront areas for education and communication about marine life – for example, through fish nurseries – and prevents opportunities for citizen activities in the transition zone between land and water.
This case explores how a bioelectrode-based solution – where electrodes are placed in the harbor sediment to improve chemical conditions – can be implemented in Horsens Harbor. The goal is not to develop the technology itself, but to determine how it can be concretely integrated into the harbor space: Where should it be placed? What should it look like? How do we communicate its function and impact to citizens and visitors?
As the aquatic environment improves, new opportunities arise for recreational and educational initiatives in and around the harbor basin. The case therefore also focuses on how we can design physical or digital elements that make underwater life visible and engaging – and how local stakeholders and citizens can contribute to preserving and using the harbor in new ways. The case is not about limiting nutrient input from the catchment area, but about how water quality within the harbor basin itself can be improved and actively used. The ambition is to develop a scalable solution that enhances biodiversity, strengthens the city’s blue identity, and serves as inspiration for other harbors.
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Case 2
Restore the water cycle – future wastewater management in rural areas (Genskab vandets kredsløb – fremtidens spildevandshåndtering i det åbne land)
This case asks the question: How can we restore the natural water cycle in rural areas – in a way that both improves the environment and builds trust and confidence among citizens and authorities?
The case will work with new solutions and principles for decentralized treatment: how can we develop technologies, facilities and inspection methods that ensure a high, documented treatment effect close to the source? How do we integrate landscape, biodiversity and local water management into the solution – instead of simply transporting wastewater away?
The case offers an opportunity to challenge 100 years of centralization thinking and explore how decentralized wastewater management is, and could become, a lever for better environmental outcomes and modern technology. This could be through physical systems, sensors or new forms of organization and collaboration. The goal is to develop concrete proposals for how small discharges can be handled smarter, greener and more locally – while at the same time creating a basis for future investments and follow-up in municipal wastewater plans and water area plans.
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Case 3
Nature as an ally – future management of shallow groundwater in urban areas (Naturen som allieret – fremtidens håndtering af terrænnært grundvand i byområder)
Climate change is already being felt in the form of increased rainfall, more cloudbursts and a rising groundwater table. In many places in Denmark, homes, infrastructure and urban spaces are challenged by water that can no longer be drained away. At the same time, it is technically and economically unsustainable to build our way out of the problems with pumping stations, sealing and large pipe systems. As legislation increasingly allows utilities to manage shallow groundwater, new ideas – and especially nature-based solutions – are needed.
This case asks how we can make nature part of the solution instead of a challenge. How can we create holistic systems that handle water where it is – and at the same time generate value in the form of green urban spaces, climate adaptation, biodiversity or recreational functions? Can we combine existing grey infrastructure with new blue-green components – and how do we ensure that the solutions also work in the climate of the future?
The case invites the development of concepts, systems and approaches that can be used in urban areas with high groundwater levels – both in new urban development areas and in older neighborhoods already experiencing the consequences of shallow groundwater. There is room for ideas ranging from micro and neighborhood level to master plans and operational strategies. At the same time, emphasis is placed on ensuring that the solutions are robust, documented and adaptable to both current and future conditions.
The goal is to formulate new answers to how we manage water where it is – and how we at the same time integrate climate adaptation, supply security, operations and nature content into one cohesive picture.
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Case 4
Gravel pits as learning arenas for future biodiversity (Råstofgrave som læringsarena for fremtidens biodiversitet)
Gravel pits represent one of the most overlooked – and largest – potentials for creating new nature in Denmark. When nutrient-rich topsoil is removed and mineral soil is exposed, a landscape emerges with light, variation and low nutrient content – ideal for many species currently in decline. In practice, however, this potential is far from realized – partly because legislation limits the regions’ ability to set requirements for nature in post-extraction restoration, and partly due to a lack of knowledge, tools and collaboration models.
This case works to develop a shared learning arena where gravel pits are used as platforms for measuring, documenting and developing biodiversity – before, during and after extraction. It’s not just about showing what’s possible, but also about creating methods and decision-making tools that can be broadly used by municipalities, regions, landowners and extractive companies. At the same time, learning and research activities are linked with practice: how do we measure biodiversity effectively? How do we involve local communities and students? And how do we create stories and ownership that can influence both the political and cultural agenda?
The case draws on existing technical knowledge, for example on quarry lakes, amphibian scrapes and restoration principles, and works with standardization and upscaling. It also explores new models for partnerships and financing – for example through nature funds, resource taxes and local ownership. The goal is to consolidate experiences and build models that can be scaled nationwide and actively used in the green transition and the implementation of both Denmark’s Green Map and the EU Biodiversity Strategy.
The case is an opportunity to work with sustainable transformation on several bottom lines: biodiversity, learning, social cohesion and land use. And not least: to create a new narrative about gravel pits as something that gives back more than it takes.
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Case 5
The water paradox – from harmful threat to valuable resource (Vandets paradoks – fra skadelig trussel til værdifuld ressource)
Rainwater and wastewater are most often associated with something to be led away – quickly and safely. It’s about avoiding floods, protecting buildings and preventing pollution. But what if we turned our perspective and asked: what is it we’re really flushing away? And what values are hidden in the water we consider waste?
This case is based on the water paradox: the same water that can threaten homes, health and nature also contains resources – nutrients, energy, organic compounds and cooling effects – which today are largely lost. The goal is to rethink our approach to rainwater and wastewater and explore how, instead of minimizing harm, we can maximize value.
The case invites idea development within both upcycling and resource extraction: how can we utilize the substances already present in the water – not only the harmful ones but also the valuable ones? How can we make rainwater something other than a threat – perhaps a local resource, a cooling element, or part of a new green business? And how do we create solutions where damage prevention and added value are not opposites but prerequisites for each other?
The case covers both rainwater and wastewater, but with a focus on identifying interfaces and applications where they can provide the most value – technologically, commercially and socially. This could involve anything from material reuse and heat recovery to communication, engagement and behavioral design.
The goal is to develop concrete ideas and principles where water is not only seen as something to protect ourselves against – but as something we can use to improve the city and the environment.
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Case 6
Basins with low discharge rates – how do we balance rainwater, agriculture and nature? (Bassiner med lavt afløbstal – hvordan balancerer vi regnvand, landbrug og natur?)
With increasing requirements for treating separate stormwater discharges for environmentally hazardous pollutants, utilities face growing challenges in finding suitable technologies and methods for stormwater treatment in cities, so that discharge permits to water bodies can be obtained. Space in cities is limited, and in many places, treatment can only be located within road areas. The available technologies using filtration/adsorption of particles are not always sufficient to achieve the quality required for a discharge permit. At the same time, there are challenges with the robustness and operation of these technologies. The result: climate adaptation and sewer separation risk coming to a halt.
This case asks: How do we move from technologies that (almost) work to solutions that function in practice – technically, legally, and economically?
It is not about reinventing filtration – but about developing ideas and strategies that make it possible to treat stormwater in practice:
- Can discharges be aggregated more intelligently?
- Can we work with zoning, local documentation, or acceptance of variation?
- Can technologies be combined, scaled, or shaped to fit reality – even when there are 40 discharges along a short stretch of stream in densely built-up areas?
The case also opens the door to examine how existing frameworks and regulations can be applied more flexibly: Are there opportunities in current legislation that are not being used in practice – perhaps due to habit, lack of knowledge, or uncertainty? And how can the sector create more clarity about what is considered “good enough” when it comes to stormwater treatment?
The goal is to bring together knowledge, practice, and innovation – and develop proposals that can be applied in real projects while also inspiring a more pragmatic and reality-based approach to stormwater in dense urban areas.
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Case 7
When technology falls short – how do we treat urban rainwater in the future? (Når teknologien ikke rækker – hvordan renser vi regnvand i byen fremover?)
With increasing requirements for the treatment of separate rainwater discharges for environmentally hazardous pollutants, utilities face growing challenges in finding suitable technologies and methods for treating urban rainwater to obtain discharge permits to water bodies. Space in cities is limited, and in many places treatment can only be located in road areas. The available technologies using filtration/adsorption of particles are not always sufficient to achieve a quality that makes it possible to obtain a discharge permit. At the same time, there are challenges with robustness and operation of the technologies. The result: climate adaptation and sewer separation risk coming to a standstill.
This case asks the question: how do we move from technologies that (almost) work to solutions that work in practice – technically, legally and economically?
It’s not about reinventing filtration – but about developing ideas and strategies that make it possible to treat rainwater in practice:
- Can discharges be combined more intelligently?
- Can we work with zoning, local documentation or acceptance of variation?
- Can technologies be combined, scaled or shaped to fit reality – even when there are 40 discharges along a short stream segment in densely built-up areas?
The case also opens up the possibility of looking at how existing frameworks and regulations can be applied more flexibly: are there opportunities in current legislation that are not being exploited in practice – perhaps due to habit, lack of knowledge or uncertainty? And how can we as an industry create more clarity about what is “good enough” when it comes to rainwater treatment?
The goal is to gather knowledge, practice and innovation – and develop proposals that can be applied in concrete projects while also inspiring a more pragmatic and reality-based approach to rainwater in dense urban areas.
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Case 8
Climate adaptation as a heat source – can rainwater and green energy be combined in smaller towns? (Klimatilpasning som varmekilde – kan regnvand og grøn energi kobles i mindre byer?)
In many smaller communities and rural areas, there is no access to traditional district heating, and it can be challenging to establish shared green heating solutions that are both technically feasible and economically sustainable. At the same time, there is a growing need for local climate adaptation where the management of rainwater and cloudbursts is combined with green solutions that relieve sewers and create new landscape values.
This case explores how climate adaptation projects and local heat supply can be integrated into new hybrid solutions. There are already a few examples where rainwater, energy and local organization come together – but there is a lack of models that can be adapted to Danish conditions and the realities of smaller towns.
The case focuses on how we can use the landscapes we are already reshaping in the name of climate adaptation to simultaneously create access to sustainable heating. In connection with rainwater management, could we establish energy storage, utilize heat from the ground or biomass, or create new energy communities around small technical installations? And what is required to make the solutions work – technically, economically and legally?
The case also opens up for examining the barriers and interfaces between climate adaptation and heat planning. Who needs to collaborate, and how can the models and partnerships be created that lift solutions from experiment to practice? And how can the municipality support or facilitate making such solutions attractive and financially viable for both citizens and suppliers?
The goal is to develop ideas and solution models where climate adaptation becomes more than water management – and instead becomes a strategic resource contributing to the green transition of heat supply in smaller communities.
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Case 9
Digital soil logistics – from hidden quantities to visible decisions (Digital jordlogistik – fra skjulte mængder til synlige beslutninger)
Today, soil management in construction projects primarily follows a linear process: soil is transported away, and new soil is brought in – often without attempts at reuse, coordination, or overview. There are neither shared data frameworks nor operational tools that make it easy for contractors to plan smarter. The result is unnecessary expenses, high CO₂ footprints, and wasted resources – both economically and environmentally.
This case focuses on developing a digital platform that makes it possible to gain an overview of soil quantities, types, classifications, logistics, and reuse opportunities – not as static reports but as active planning tools. The ambition is to make it easier and more attractive for contractors to think circularly from the start of a project.
The case builds on experiences from industry stakeholders and will jointly explore what data already exists, how it can be standardized, and how digital solutions can be used to make better decisions earlier in the process. It’s not just about technology but about creating a new practice for soil management – where exchange, reuse, and optimized transport become the standard rather than the exception.
The goal is to develop the foundation for a platform that can be applied across projects and, over time, change the entire industry’s approach to soil as a resource – resulting in lower climate impact and better economics.
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Case 10
Coastal protection of Odense inner harbour – making it Denmark’s greenest harbour (Kystbeskyttelse af Odense indre havn, og gøre den til Danmarks grønneste havn)
Odense Municipality has a clear ambition: to develop the Inner Harbour into Denmark’s greenest harbour. This requires that coastal protection and climate adaptation be considered as part of a broader transformation where technology, nature and urban life merge.
A key challenge is the choice between a local solution – a climate edge – and a regional solution in the form of a sluice in the Odense Canal. Which path should Odense take, and how can the solution support both green urban development and climate adaptation?
This case focuses on how an urban, green climate edge can be established and function both as coastal protection and as a catalyst for recreational urban spaces, increased biodiversity and new connections between the city and the water. The case builds on nature-based principles and will work with ideas for living shorelines, multifunctional edges and dynamic landscape elements that can adapt to rising water levels and strengthen the city’s resilience.
The ambition is to develop a flexible and future-proof solution that can already today leave a green and visible mark on the path toward Denmark’s greenest harbour.
The case contributes directly to Odense Municipality’s risk management plan and opens the door to applying tools such as DAPP (Dynamic Adaptive Policy Pathways) in practice.
Beyond the case, it also explores how a possible future sluice solution can be integrated into an overall master plan, and what connections can be created between the two tracks – in addition to the local businesses, citizens and active agriculture along the Odense Canal. This part is being handled by Odense Municipality in parallel.
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