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The Aqua Renew Nature-Based Solution (NBS) wastewater treatment project is proposed for implementation in the Danube Delta, Romania, to address the challenges of wastewater treatment in remote and ecologically sensitive areas. Eco-tourism in the Danube Delta, which is a UNESCO World Heritage Site, faces significant difficulties in wastewater management due to limited access to centralised treatment infrastructure. The Aqua Renew NBS provides a decentralised, low-maintenance, and environmentally friendly alternative, designed specifically for off-grid guesthouses operating in this unique natural landscape.
The system integrates multiple components: an Imhoff tank, constructed wetlands, zeolite filtration, and a rainwater harvesting unit. Together, these elements treat wastewater, recycle nutrients, improve water quality, enhance biodiversity, and produce biogas as a renewable energy source for guesthouse operations.
Quantifying the Impact
The compensation potential of the system was assessed using the Water Footprint Network (WFN) and ISO 14046 methodologies.
The WFN method focuses on the greywater footprint, representing the volume of water that would have been required to dilute pollutants to acceptable standards. This approach indicates that the Aqua Renew NBS system can generate 11.09 CAPs annually and 55.44 CAPs over five years.
The ISO 14046 method evaluates the volumetric equivalent of the impact mitigated by the project, producing a much higher estimate of 87.0 CAP equivalents annually and 435.07 CAP equivalents over five years.
1 CAP represents 1,000 m³ of water saved or impact mitigated.
This results in a unit cost of €172.42 per CAP using the WFN method and €21.97 per CAP equivalents using the ISO method, highlighting the cost-effectiveness of decentralised, nature-based treatment solutions in delivering measurable water compensation benefits.
Social, Economic and Environmental Co-Benefits
The project offers a range of additional benefits beyond its direct water treatment impact:
Social Benefits
- Enhances environmental education and community awareness
- Builds local capacity through training and workshops
- Encourages stakeholder collaboration and participation
Economic Benefits
- Creates direct and indirect job opportunities
- Supports local businesses through eco-tourism
- Reduces expenses linked to conventional infrastructure and municipal services
Environmental Benefits
- Improves water quality and promotes nutrient recycling
- Creates habitats that support biodiversity
- Lowers carbon emissions through the production of biogas as a clean energy source
Looking Ahead
The Aqua Renew NBS wastewater treatment project demonstrates how innovative, nature-based technologies can address pressing water management challenges in sensitive environments. By combining wastewater treatment, nutrient recycling, biodiversity enhancement, and renewable energy production, the system offers a holistic approach to sustainable water stewardship. With its high CAP generation potential and strong co-benefits, this project serves as a model for other remote or ecologically valuable regions seeking decentralised water solutions.