Sustainable food security - WalNUT



WALNUT project, Closing waste water cycles for nutrient recovery, is a 54-month collaborative Research and Innovation Action (RIA) funded with 5.9 million € by the EU in the framework of the Horizon 2020 call H2020-RUR-2020-2. It started in September 2021 and is coordinated by the FUNDACION CARTIF (Spain). The WALNUT project brings together 14 partners from 8 EU countries to address the current gap in nutrient cycles of different European wastewater treatment systems and their related environmental problems.

Project description

The high growth rate of world population and relative consumption demand is putting significant pressure on the food industry at different levels to multiply its production capacity. To meet this additional demand requires an increase of the already intensive agricultural practices, leading to a high land, water, energy, and fertilisers use. Therefore, the request for effective and high-performance plant nutrients is expected to reach unprecedent levels.

WalNUT aims to close the waste water cycles for nutrient recovery. Waste water streams are considered a promising resource to mitigate the soil nutrient imbalance and to recover nutrients for plant fertilising purposes. Nutrients from this large-scale recovery process can be used for bio-based fertilisers offering a new, circular and sustainable model to tackle the limited nutrient-mineral reserves and its crucial environmental issues. These bio-based fertilisers will ensure food safety, minimise waste water carbon footprint and protect nutrients natural reserves. WalNUT will provide 5 solutions tested at a relevant scale and 12 validated technologies for nutrient recovery to produce 4 bio-based fertilisers that are commercial, safe and sustainable.


These are the objectives of WALNUT:

  • Analyse inter and intra-regional EU nutrient imbalances

WalNUT will map the current situation within EU-27 on waste water streams generation, nutrient distribution and relevant legal frameworks, establishing the baseline against which to compare innovation and progress of bio-based fertilisers based on nutrient recovery.

  • Develop sustainable and resource-efficient technological solutions for nutrient recovery

WalNUT will select 5 most promising technologies for nutrient recovery to be scaled up in 5 pilot plants at different key sites, pursuing the economic profitability of the bio-based fertilisers obtained while minimising environmental risks and impact.

  • Environmental and socio-economic impact assessment of the proposed solutions

Through the adoption of life-cycle models, WalNUT will measure the impact produced by the solutions for nutrient recovery on climate change, human and ecosystem health, biodiversity and resource scarcity.

  • Assess the agronomic efficiency of safe bio-based fertilisers

A wide range of nutrient-rich output products will be produced and evaluated for different agronomic applications, evaluating their potential to replace conventional, non-renewable minerals.

Role of Ghent University

UGent is the leader of WP4 that deals with Demonstration and validation of biofertilisers at relevant scale, and manages a field site for this WP. UGent is also responsible for the lab scale testing of HRAS/CS + adsorption/ion-exchange technology (WP2) for municipal waste water treatment. In WP3, UGent collaborates with Aquafin on pilot developments related to HRAS/CS + adsorption/ion-exchange and stripping/scrubbing technology.




Prof. Erik Meers
Department of Green Chemistry and Technology
Phone number: +32 9 264 93 96