Researchers at the OCAPI research program in France say human urine could be a valuable alternative to chemical fertilisers. They think it could be effective and less polluting than existing crop fertilisers.
Researcher Fabien Esculier told Euro News that urine is a nutrient-rich alternative filled with nitrogen, phosphorus, and potassium. He emphasises that urine is less polluting than synthetic fertilisers.
According to OCAPI, the nutrients in urine could be separated at source and used in agriculture. Once the urine is separated different treatments can be applied to stabilise nitrogen, reduce the volume, treat contaminants or extract nutrients.
With the Ukraine war causing fertiliser shortages and rising prices, the use of urine as fertiliser has been attracting more interest lately. There are already several initiatives that collect urine for this purpose.
The Rich Earth Institute in Vermont has been advocating urine-recycling for years. The Institute has been applying sanitised urine to hay fields and quantifying the crop yield. Its research shows there was no statistically significant difference in yields of hay fertilised with diluted urine, undiluted urine and synthetic fertiliser.
The institute acknowledges that because urine contains so much water, it can be expensive to transport and store, and also labour intensive to apply to farmland. The nitrogen in stored urine has the form of ammonia, which is prone to evaporation and requires special handling during fertiliser application.
To counter these challenges, the researchers of the institute are experimenting with innovative methods for stabilising the nitrogen in urine, as well as with adapting reverse osmosis equipment (used by boaters to make drinking water from seawater) for use in producing a concentrated fertiliser product.
And on Gotland, an island in Sweden, researchers are collecting urine from waterless urinals and specialised toilets during the summer tourist season. The team from the Swedish University of Agricultural Sciences (SLU) in Uppsala, has founded a company called Sanitation360. Using a process that the researchers developed, they are drying the urine into concrete-like chunks that they hammer into a powder and press into fertiliser pellets that fit into standard farming equipment.