The conventional municipal wastewater systems recover only a small part of the plant nutrients found in the wastewater to farmland. The purpose of the project is to gather important stakeholders in the flow of nutrients from the households to farmland to assess the potential and, hopefully, further develop a urine separation system that has been developed by SLU.
Almost all nutrients (>85% of the total amounts of nitrgen, phosphorus and potassium) in the municipal wastewater is found in the toilet wastewater. The urine contributes for almost 85% of the nutrients in the toilet wastewater.
The need to decrease the dependency of importing plant nutrients is large to secure a resilient food supply. The national potential for substituting imported nutrients in mineral fertilisers with urine nutrients are 20%, 30% and 40% of the nitrogen, phosphorus and potatssium respectively.
The specific solution of the project is that the urine is diverted in the toilet and not mixed with flushwater and feces. The urine is lead to a drying chamber in the toilet room. In the drying chamber biochar (e.g.) is utilised as a drying medium and ventilation air is used as a heat source. The end-product, a powder, which is a mix of dried urine and biochar, is collected a couple of times a year for central processing and storage. The aim is to produce a commercial viable fertiliser with a nitrogen content of 20%.
For the exploitation area Sege Park in Malmö a sustainability strategy has been set up by the City of Malmö. In this document VA SYD and the City of Malmö have agreed of acting for that at least one multi-storey building will install a urine separation system.
The project is co-financed by Vinnova, Utmaningsdriven Innovation – steg 1 initiering