OpenIDEO is an open innovation platform. Join our global community to solve big challenges for social good. Sign Up / Login or Learn more


Nature-based solutions for recovering nutrients & water from waste streams for fertigation leading to a new era of agricultural production

Photo of Theresa Heitzlhofer
5 10

Written by

Lead Applicant Organization Name

alchemia-nova GmbH

Lead Applicant Organization Type

  • Small company (under 50 employees)

Website of Legally Registered Entity

How long have you / your team been working on this Vision?

  • 3-10 years

Lead Applicant: In what city or town are you located?


Lead Applicant: In what country are you located?


Your Selected Place: what’s the name of the Place you’re developing a Vision for?

3 Greek Islands: Lesbos, Myknos, Tinos; covering an area of 1.935 km2. System scalable to inhabited coastal areas in Mediterranean Region.

What country is your selected Place located in?

Greece, Europe.

Describe your relationship to the place you’ve selected.

The founder and innovation leader of alchemia-nova, Johannes Kisser, is half greek and spends half of his lifetime in Greece. alchemia-nova is active in a H2020 research project with demo sites on Lesbos, Tinos and Mykonos: HYDROUSA - combining traditional construction techniques respecting the local landscape together with innovative technologies for rainwater harvesting and waste water treatment. (Grant agreement No. 776043). We selected this place because it serves as a model for many replication sites, struggling with similar challenges. There are thousands of Mediterranean Islands, and thousands of replication sites worldwide.

Describe the People and Place: Provide information that would be helpful for an outsider who has never been there and may have no context about this Place to better understand the area.

Greece is a country located in Southeast Europe and a member state of the European Union. Its population is approximately 10.7 million as of 2018. Greece has the longest coastline on the Mediterranean Basin, featuring many islands, of which 227 are inhabited. Greek islands belong to the Mediterranean Region, with typically hot, dry summers and mild, humid winters. Greek islands are visited by millions of tourists every year, specially during summer months. Added to natural water scarcity in summer, those tourists cause another shortage on fresh water and create tons of waste water, thereby putting pressure on the fragile ecosystems. Mediterranean Food is characterized by the use of olives (& oil), wheat (& bread), grapes (& wine), as well as vegetables, spices, fish, rice and pasta. Greek islands are inhabited by Greek orthodox people (majority) and numerous other groups of people. Since the latest migratory wave in 2015, Greek islands face a high number of asylum seekers from different countries. Greece is considered the cradle of Western civilisation, being the birthplace of democracy, Western philosophy, Western literature, historiography, political science, major scientific and mathematical principles, Western drama and notably the Olympic Games. Greece is well known for its ancient high culture, today present in form of famous sightseeing spots (temples, archeological excavations, etc.). The primary sector is counting for only 4% of the GDP, 22% of it produced for export. The tertiary sector is the strongest sector, counting for approx. 80% of the GDP, with tourism being the largest part.

What is the estimated population (current 2020) in your Place?


Challenges: Describe the current (2020) and the future (2050) challenges that your food system faces.

The possible implementation of water loops in the Mediterranean areas faces severe barriers, which need to be overcome to foster environmental and economic development. The annual available surface and groundwater resources in Mediterranean (MED) countries are approx. 1080 km. Although these may seem sufficient, they are irregularly distributed, with countries having water reserves of less than 500 m3/capita/year, and many areas having less than 1000 m3/capita/year (UN water stress level). Agriculture is the prime consumer of water in the Mediterranean (>72% of total consumption). Water reserves are scarce, while high touristic activity during the summer months places severe stress on the limited water reserves in terms of quantity and quality. Remote areas often do not even have access to tap water. Water scarcity and the lucrative touristic activities often result in reduced agricultural activity because there is not enough water for agricultural activities and/or it is of poor quality. The development of desalination plants to produce freshwater from seawater severely stresses the energy grid and results in the production of large quantities of brine, which are not valorised. The practice of excessive groundwater pumping for irrigation, results in seawater intrusion into the aquifer and reduced crop yields. The wastewater treatment plants (WWTPs), as far as they exist, are often too overloaded to cope with the high seasonal loads, while some regions are not serviced at all. A common strategy of many MED areas is still wastewater discharge without (sufficient) treatment into the sea. In many rural and remote areas wastewater management is confined to septic tanks/pits with adverse environmental consequences to land and groundwater. Malpractices are often the case with inadequate quality of treated wastewater being used for irrigation or discharged into water recipients. In addition, municipalities, which are short of funds, are not able to sustain energy intensive wastewater treatment processes. The concept of circular economy for water is not practiced in most MED regions. The gradual implementation of the Water Framework Directive and the Urban Waste Water Treatment Directive have improved water/wastewater management, resulting in the development of some infrastructure. At the same time, the joint EU-UNEP initiative to depollute the MED Sea is accelerating investments in large WWTPs. Nevertheless, many MED regions still face significant challenges in terms of water management. As a consequence, considering the water-energy-food nexus, activities within the concept of circular economy are urgently required within the Mediterranean. In terms of demography, Greece faces challenges dues to recent migration aspects,.

Address the Challenges: Describe how your Vision will address the challenges described in the previous question.

The main objective of HYDROUSA is to offer a set of solutions for these problems that are easily adaptable and replicable to other possible circumstances around the world. This overall aim will be achieved by accomplishing the following project specific objectives: 1) Demonstrate that circular nature-based technologies work for supplying fresh water from non-conventional water sources 2) Demonstrate that circular nature-based technologies work for wastewater treatment and nutrient recovery while creating further environmental and societal benefits 3) Show that the applied technologies are feasible within existing (legal) constraints and create economic return, hence create jobs and boost the economy 4) Make sure that the community and stakeholders are engaged in all parts of the value chain from the very beginning 5) Prove that skilled workmanship combined with modern ICT solutions create resilient and attractive long-lasting systems 6) Establish the water-energy-food-employment nexus and work with true cost accounting as tool for circular economy assessment 7) Replicate this concept to as many other places as possible and spread the good news HYDROUSA will - increase the supply of fresh water: from rain water, storm water, vapour water, waste water - make use of nutrients in waste water: reuse nutrients, decrease fertilizer import, yield increase of local traditional crops, fertigated area - create benefits on energy: use energy from constructed wetlands, energy from biogas - create environmental benefits: decrease water intensity use index, save CO2 in comparison to conventional systems, enrich biodiversity - create social benefits: donation of edible crops to refugee camps, areas for recreational purposes - produce additional goods: fruits, vegetables, salt - engage citizens and generate outcomes: co-creation of circular business models, develop eco-tourism concepts, increase tourism in winter season - include workmanship - integrate ICT control: automated irrigation, monitoring of in-situ data in real time - establish a measurable nexus including true-cost-accounting - inspire and support replication sites worldwide - disseminate project results

High Level Vision: With these challenges addressed, now provide a high level description of how the Place and the lives of its People will be different than they are now.

We are in the year 2030, in the middle of the summer, on a Mediterranean island, again with new record temperatures reaching almost 45°C. We seek shade and freshness in the lush greens of the biodiverse agricultural forest right next to the central village of the island. We feel as though we are in an oasis, we can hear the water gurgling, while we walk over beautifully handcrafted stone works and look at smaller waterfalls here and there. We wonder for a second, where this water comes from in this otherwise dry dusty island, when we remember the big sign at the entry of this green area, saying that all this water is actually our wastewater, which has been flushed down the toilets and the sinks of our showers and the fresh water is produced from the sea and the atmosphere just with the help of the sun. Our thoughts turn back 10 years ago, when people were still using short-sighted solutions carrying sweet water from the mainland to flush it down the toilets and send it to the ocean. We realise that since then people moved back to their ancestors’ villages. There are jobs, there is water, products are being manufactured, skilled craftsmen are combining traditional workmanship with modern computer technologies. Tourists come all year round to visit these green sites, looking out for these famous recreational parks that have become biodiversity hotspots, even jumping from island to island to see all these different green places, as described in eco-tourist guides. At the end of our holidays, we ask ourselves, why don’t we have this kind of wastewater utilisation in Northern Europe, where we come from, and try to think about how we could generate new ecosystems with wastewater in our cities, parks, regions? We go back and can directly start implementing our case, as we find guidelines on the internet under the HYDROUSA name and logo, developed back in 2020 by a team of innovators that were able to adapt to future needs.

Full Vision: How do you describe your Vision for a regenerative and nourishing food future for your Place and People for 2050?

The HYDROUSA vision is based on the use of nature-based solutions (NBS) for water treatment and resource recovery on three Greek islands (Lesvos, Mykonos, Tinos). HYDROUSA turns arid and unproductive areas into functional green areas, so called “green infrastructures”. 


HYDROUSA combines the food-water-energy-nexus to create a self-sustaining, restorative agriculture-based way of living. HYDROUSA vision includes circular management of water and organic nutrients – besides sunlight, the two basic needs for food production. These two basic needs are now scarce (fresh water for irrigation, phosphorus) and / or derive from energy intensive sources (desalinated water, fresh water shipped from mainland, nitrogen).

In HYDROUSA water and organic nutrients are extracted from local areas of occurrence using NBS such as solar-based constructed wetlands / desalination units, and gravity / evaporation driven filtration:

  • Water sources are wastewater, sea water, rainwater, and atmospheric humidity.
  • Nutrients are recovered from wastewater.

The proposed NBS have the power to implement regenerative agriculture with the aim to re-green areas plagued by erosion and agricultural malpractices, enhance biodiversity and facilitate sustainable development.

HYDROUSA’s impact on...


The use of NBS in HYDROUSA will influence the economy strongly. First, the intended NBS will greatly reduce or eradicate costs in respect of fresh water shipping, energy intensive desalination systems, centralised and inefficient wastewater treatment plants, and synthetic fertiliser. NBS in general are energy and cost efficient. The use of NBS creates new options (jobs, income sources) along the value chain of water treatment, nutrient recovery and food production. New green jobs arise in the following areas: construction, installation, implementation, monitoring, educating of constructed wetlands and fresh water harvesting units; management of wastewater / nutrient streams; planning, implementation, monitoring of agroforestry systems and biogas production. In HYDROUSA revenue streams are diversified, as waste, waste-water and nutrient management, as well as food production become a strong production line besides tourism. Concerning tourism, HYDROUSA strengthens eco-tourism approaches, resulting in a healthier environment and creating sustainable jobs.

HYDROUSA creates new circular business models, focusing on circular procurement, resource recovery, product lifetime, a sharing economy and product-as-a-service.

HYDROUSA will attract media attention, the three islands will be presented as frontrunner areas, motivating replication sites worldwide.


The use of NBS in HYDROUSA encourages the consumption of locally produced food. Oriented on permaculture agroforestry systems, HYDROUSA will also diversify food options. People on Mediterranean islands already have quite a healthy diet based on vegetables, fruit, and herbs. Of course, fish, meat, dairy and derived products are among traditional nutrient sources as well. HYDROUSA will support a shift towards a more vegetarian diet, as reclaimed production sites will produce mainly vegetarian oriented foods.


With HYDROUSA, a new era is dawning. Societies will move from fossil fuel-based industries towards cost and energy efficient nature-based technologies, creating wealth through the combination of ancient approaches (e.g. water streams subsurface with stone channels) and modern ICT (automated sensor integration and data monitoring). NBS create ecosystem services while simultaneously triggering benefits for the ecosystem (enhancement of biodiversity, humus accumulation, water retention, etc.). NBS proposed in HYDROUSA are mainly plant-based, meaning involved areas are green, plants maybe flowering and fragrant, attracting animals. In HYDOURSA, people will learn to use plants strategically – not only for food production and decoration, but also for water / air treatment and nutrient recovery specifically, and ecosystem services in general. HYDROUSA NBS are silent, slow and robust against climate variables. HYDROUSA NBS are extremely exciting, inviting and addressing a new type of tourist. Local eco-tourism approaches are also supported under the project. HYDROUSA NBS are easily transferred to other areas with similar conditions, and will result in a high number of replication sites by spreading the good news.


The use of NBS in HYDROUSA requires new regulation and governance strategies towards small scale and decentralized approaches, a balanced mix of top-down and bottom-up strategies, with major focus on participative processes in decision-making. The initial change will be supported by community building activities, led by experts from the research project´s consortium, resulting in more intensive interactions between people as well as between people and their representatives. When political framework conditions are changed to provide for greater participation by stakeholders, this will directly influence the “culture” of the involved people.


The use of NBS in HYDROUSA support a paradigm shift from linear production-consumption-disposal patterns towards a circular and sustainable economy. They shed light on the power of nature and include ecosystem patterns / behaviours in every decision-making process. HYDROUSA NBS create a positive basic condition for human-nature interactions. They will not only change the way people interact with nature but also the way people interact with each other. Once implemented, HYDROUSA NBS will result in a deeper understanding of ecosystem functionalities, thereby creating more tactful and less harmful human-nature interactions. HYDROUSA NBS offer an effective counterbalance to an otherwise “fast-loud-dirty-unhealthy” lifestyles, supporting the “slow-food” movement, low tech solutions, long-term perspectives and healthy ecosystems including mankind.


The use of NBS in HYDROUSA will result in higher resilience of the involved systems, bringing multilevel benefits to ecosystems, to their flora and fauna. HYDROUSA NBS require the strategic application of selected plant species, thereby enhancing biodiversity and interactions between individual species. HYDROUSA NBS will attract birds, insects, and other wild animals by offering habitats and nutrition. They support humus generation and soil conditioning, leading to better farming conditions. Accordingly, HYDROUSA NBS generate a win-win situation for nature and society.

How did you hear about the Food System Vision Prize?

  • Email


Join the conversation:

Photo of Nerina Efthymiou-Charalampopoulou


Photo of Maria Wirth

Amazing! This is a truly sustainable solution.

Photo of Theresa Heitzlhofer

Thank you Andrea, Itika and Constanza! We will work on the vision. Is that to change the content of the last box called "Full vision: How do you describe your Vision for a regenerative and nourishing food future for your Place and People for 2050?" Kind regards, Theresa

Photo of Andrea Vaz-König

Hi Theresa Heitzlhofer !
I would like to encourage you to further develop your proposal from a solution to a vision. It may be helpful to revert to the criteria defined in the toolkit and further grow alongside them - you can find them directly here:

Looking forward to seeing your vision develop further!


Photo of Itika Gupta

Hi Theresa Heitzlhofer  Great to see you joining the Prize!
It is fascinating to see a Vision come together to sustainably use waste streams to use water and nutrition for agriculture.
We noticed your submission is currently unpublished. Was this your intention? We'd love to have your submission included in the Prize. Even if you've not started populating your Vision just yet, by publishing your submission you can make it public for other teams in your region to see, get in touch and possibly even collaborate with you.
You can publish it by hitting the "Publish" button at the top of your post. You can also update your Vision at any time before 31 January 2020 by clicking on the "Edit Contribution" on top. If you need inspiration or guidance, take a look at the Food Vision Prize Toolkit.
Here is the link to the Prize Toolkit:

We look forward to seeing your Vision submission.