Closing the nutrient cycles between urban and rural areas
The nutrient recycling concept envisaged in RUN and the path to a regionally closed cycle is complex. The starting point is the "basic material" of domestic bio-waste and domestic wastewater (top right in the image):
Exclusively domestic wastewater, i.e. not industrially or commercially contaminated wastewater, is discharged from a residential area via drainage pipes, and afterwards collected and fed to the pilot plant. The organic kitchen waste is collected by waste disposal companies. This is how the raw material is made available for processing.
In the pilot plant - a treatment plant especially developed for this purpose - kitchen waste and black water from the toilet are prepared and processed under strict criteria. At the end of the recycling process, the nutrients nitrogen (N), phosphorus (P) and potassium (K) are filtered out of the waste material in their pure form and processed into other recycled products.
High-quality design fertilizer, biochar and bioplastic, e.g. for the use as silage film, will be produced and used in agricultural production. Agricultural companies near the pilot plant can use these products for the production of food or feed.
Vegetables, cereals and many other foods that have been manured with the recycled fertilizer are offered at regional farmer's markets. Through recycling and processsing local wastewater and organic waste disposal important nutrients are brought back into the nutrient circle.
(c) RUN 2019