Most of us rarely think about what happens after water disappears down the drain. Whether it’s from toilets, sinks, or showers, wastewater vanishes into underground pipes and far-off treatment plants. Out of sight, out of mind.
But in times of water scarcity, rising fertilizer costs, and increasing pressure on agriculture, this hidden flow is far too valuable to disregard and waste. Instead of treating wastewater as a problem, circular and nature-based solutions (NbS) can help us see it as a resource — one that can support both water security and local food production.
This is exactly what’s happening in Cambium eco-village in Fehring, Austria, where the vertical green wall treatment system vertECO® is turning wastewater into nutrient-rich water for safe reuse in irrigation and fertigation of the local market garden. In the GEORGIA project, we spotlight how this kind of water treatment and reuse systems support resilient agriculture and circular food systems — and Cambium is one of the sites demonstrating how this works in practice.
Figure 1: vertECO® green wall treatment system at GEORGIA Pilot site, Cambium eco village (c) alchemia-nova
vertECO®: from wastewater to safe irrigation water:
The vertECO® is essentially a vertically, stepwise aligned treatment wetland. After simple pre-treatment, household wastewater flows through modular planted green wall units. Invisible heroes, namely microorganisms in the substrate biofilm and plant roots (rhizomes), perform most of the work by removing pollutants and converting nutrients, apart from other removal mechanisms such as filtration, sedimentation or adsorption. Finally, ozonation eliminates the remaining pathogens and ensures the reclaimed water meets the EU Water Reuse Regulation (2020/741).
Scientific monitoring shows that even with a small share of Cambium’s wastewater, most of the garden’s irrigation needs can be met while also providing key nutrients such as phosphorus and nitrogen. The analysis confirms that the market garden’s water and nutrient demands can be covered across a range of crops — all while complying with the EU Water Reuse Regulation (2020/741), ensuring both safety and sustainability ([1], [2]).
Figure 2: GEORGIA Pilot Cambium market garden (c) Cambium
GEORGIA: from eco-village to resilient farming
The GEORGIA project explores how NbS like vertECO® can help farmers achieve more resilient water management in agriculture across Europe. Cambium serves as a pilot site: It proves that safe wastewater treatment and reuse is possible, and it shows that local food production can thrive using reclaimed water and nutrients. It provides data and insights that can be scaled up to farms and agricultural cooperatives across Europe and beyond. Material flow analysis confirms that even modest systems can cover most water and nutrient needs. At larger scales, combining green walls and other types of treatment wetlands or water treatment NbS, together with rainwater harvesting or anaerobic digestion of organic waste unlocks even greater potential for circular, resilient farming [1].
Rethinking “waste”
The Cambium story demonstrates a simple but powerful point: wastewater is not waste. It is a continuous, reliable source of both water and nutrients — something rainwater and compost alone cannot offer.
For Cambium, this means irrigated gardens, fresh produce, and reduced reliance on external inputs. For GEORGIA, it is part of a bigger vision: transforming water management for resilient farming. By showing how decentralized NbS can close loops locally, Cambium helps illustrate how agriculture and circular food systems can become more self-sufficient, resilient to droughts, and better prepared for a more sustainable future.
References
[1] Vobruba, T., Wirth, M., Hartl, M., Kisser, J., Podmirseg, D., Gebetsroither-Geringer, E., Huber-Humer, M., & Langergraber, G. (2025). Analysis of material flows and resource potential of decentralized water management: On-site water and nutrient reuse in an Austrian eco-village and its upscaling to urban environments. Environmental and Sustainability Indicators, 26, 100660. https://doi.org/10.1016/j.indic.2025.100660
[2] Vobruba, T., Hartl, M., Langergraber, G., Pucher, B., Gattringer, H., Bertino, G., Panzenböck, F., & Kisser, J. (2025). vertECO® vertical green wall system demonstration for domestic wastewater treatment and on-site reuse in an Austrian eco-village. Ecological Engineering, 211, 107460. https://doi.org/10.1016/j.ecoleng.2024.107460
