SP.20.014 – Closing the N loop reusing nitrogen from sewage treatment

Route: Sustainable production of safe and healthy food

Cluster question: 015 How can we make agricultural production systems more sustainable as the worldwide demand for healthy, safe food continues to grow?

Currently large amounts of nitrogen are being added to the Dutch nitrogen system via import of feed and production of nitrogen containing fertilizer based on atmospheric N2 and fossil gas via the energy intensive Haber-Bosch process. At the same time we loose a large part of the N released via human excretes at sewer water treatment installations via energy consuming nitrification/denitrification to atmospheric N2. To get the N loop in balance the N addition must be reduced and reuse enhanced. To compensate the anticipated lower fertilizer usage and still have sufficient N (and other nutrients) for crop cultivation, the N from human excretes from sewer treatment can be used. This also results in significant reduction of energy consumption and CO2 emission. Crucial is that the composition and effect on crop growth is comparable to current practice and quality, reproducibility and safety guaranteed. This circular approach is based on state-of-the-art biorefining principles using physical/chemical separation processes where valuable components such as nitrogen, but also phosphates, organic matter and micronutrients are extracted and reused. Developments in innovative recycle and reuse from sewage water are still too costly, but with the right research and upscaling this promises to be a sustainable and feasible solution. Wageningen UR is already collaborating with Witteveen + Bos and waterboard Vallei en Veluwe on several promising initiatives and pilots. Also the fertilizer production industry has set a number of ambitious goals in this area in their new vision ‘Fertilizer 4.0’, developed together with WUR. With various stakeholders WUR wants to develop the cost and energy effective processes and products that are needed to bring back the balance in the Dutch N loop. And with that contribute to a circular and integrated system where agriculture, water and food are in balance with positive impact on the environment.


biorefining, Circular nitrogen, fertilizer, recycle, reuse, water treatment


Organisation Wageningen Food & Biobased Research
Name Dr. ir. M.E. (Marieke) Bruins
E-mail edwin.hamoen@wur.nl
Website https://www.wur.nl/en/Research-Results/Research-Institutes/food-biobased-research.htm