Fertilizer from human excrement to drive forward the circular economy

(CONNECT) The joint impact project of Kompotoi, a Winterthur-based company in the field of mobile composting toilets, and the Swiss network for recyclable sanitation systems, VaLoo from Zurich, has investigated the possible use of composted human waste as fertilizer. Supported by the Migros Pioneer Fund, dry toilet contents were composted for two years in collaboration with Kunz Baumschulen AG from Uster ZH and then analyzed. As Kompotoi reports in a press release, the results show that the resulting humus fertilizer is of high quality and safe and also contains fewer pollutants. Used in agriculture and horticulture, it could drive forward the circular economy.

In addition to the existing quality targets for composts, the fertilizer from human waste was examined for other factors such as pathogens and drug residues. While pathogens are destroyed in the composting process, according to recent research, pharmaceutical residues in recycled fertilizer are lower than in other fertilizers such as manure. "It is exciting that compost from dry toilet contents often contains significantly lower concentrations of antibiotics than manure, which can be used as fertilizer in Switzerland," said Lena Schinkel, co-researcher and research associate at the Swiss Federal Laboratoriesfor Materials Science and Technology (Empa), in a press release.

In addition, the compost enables the recycling of valuable resources such as nutrients and drinking water. According to Kompotoi, in order to exploit the potential of the fertilizer for the circular economy, a legal framework that clearly regulates the composting of dry toilet contents throughout Switzerland must now follow. Together with the Canton of Zurich and the Federal Office for the Environment, a leaflet is therefore being drawn up to create this legal framework. ce/nta