Throughout the years we've come across some pretty surprising uses for urine. This humble yellow liquid — a by-product secreted by our kidneys — has proven to be a remarkably versatile source of sustainable power and a vehicle for some seriously experimental design.
Here are six examples we've come across, ranging from the practical to the genuinely bizarre. Some will make you reconsider where waste ends and resource begins.
1. For heating a house
The Barn House in Japan's Memu Meadows is an award-winning experimental dwelling heated by urine. Designed by Keio University's Co+Labo department, it shelters two humans and two horses — producing both heating and organic plant fertiliser from the equines' contributions.
2. For making furniture
The Dupe stool is a surprisingly sturdy, compostable seat made from bacteria, sand and pee. Created by UK art student Peter Trimble using a self-made machine, this low-cost, low-energy sandstone design is the result of a biological reaction. At the end of its lifetime the stool can be broken up and used as fertiliser.
3. Culinary uses (this one's a bit out there)
'Virgin Eggs' are a Chinese delicacy from the city of Dongyang, made by boiling chicken eggs in urine collected from boys under the age of 10. The traditional springtime snack is said to have nutritional qualities that boost the immune system. We can't say we've tried them.
4. For growing teeth
False teeth have historically been made from animal bones, wood, even gold. But researchers at the Guangzhou Institutes of Biomedicine and Health have now grown tiny tooth-like structures from stem cells harvested from human urine, mixed with other organic material. Early days, but the first urine-grown teeth exist.
5. For powering phones
A team at Bristol Robotics Laboratory developed the world's first pee-powered cell phone, using microbial fuel cells (MFCs) that feast on urine and produce electricity as a by-product. Unlike solar or wind, it doesn't require special atmospheric conditions — which makes it potentially useful in disaster zones and off-grid settings.
6. As a power source
Four Nigerian teenage girls developed a DIY generator that produces six hours of power from one litre of urine. The device has an electrolytic cell that removes hydrogen, which is then purified through liquid borax. Presented at Maker Faire Africa — a glimpse of what creative young minds can do with cheap chemistry and an abundant resource.
The boring (but useful) seventh use
None of the above quite covers what most of our customers do with their urine after it's diverted by a We-Pee separator. The most common option is to dilute it 10:1 with water and use it as a high-nitrogen fertiliser — particularly good for leafy greens, sweetcorn, brassicas and fruit trees. Less photogenic than urine-powered houses, but genuinely useful.
If you're building a compost toilet and want a urine separator that diverts the wee away from the solids reliably, see our £31 original or £40 Complete.