Sweden’s largest island — Gotland — is pinning its hopes on human urine due to fresh water crisis.
According to a nature.com report, a team of researchers collaborated with a local firm that rents out portable toilets. Their goal was to collect over 70,000 liters of urine for more than three years from waterless urinals and specialised toilets at several locations during the booming summer tourist season.
The researchers are from the Swedish University of Agricultural Sciences (SLU) in Uppsala. The team developed a process with which 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.
A local farmer uses the fertiliser to grow barley that will go to a brewery to make ale – which, after consumption, could enter the cycle all over again, the report said.
It further said that the team aims to take urine reuse “beyond concept and into practice” on a large scale, says Prithvi Simha, a chemical-process engineer at the SLU and Sanitation360’s chief technology officer.
The aim is to provide a model that regions around the world could follow. “The ambition is that everyone, everywhere, does this practice.”
Project Gotland is part of a wave of similar efforts across the globe to separate urine from the rest of sewage and to recycle it into products like fertiliser.
That practice, known as urine diversion, is being studied by groups in the United States, Australia, Switzerland, Ethiopia and South Africa, among other places, the report added.
Nutrients in human urine
When somebody consumes food, their kidneys filter out excess nutrients that our body is unable to use, and these nutrients are then expelled from the body in the urine.
The urine contains significant levels of nitrogen, as well as phosphorous and potassium. The relative ratios are typically around 11 parts nitrogen to 1 part phosphorus to 2.5 parts potassium.
Studies conducted in Sweden (Sundberg, 1995; Drangert, 1997) show that an adult’s urine contains enough nutrients to fertilize 50-100% of the crops needed to feed one adult.
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