Pee fanatics want to feed the world with your liquid gold

Getty Images / WIRED

In a brightly-lit laboratory in the south of France, nestled between fields of wheat and sunflowers, bottles of human urine are gently jiggling around in an incubator. In a warehouse next door, 1,000-litre vats of the amber liquid are stacked ceiling-high while they wait to be processed. Welcome to Toopi Organics, the startup that wants to turn pee into profit.
It’s no secret that urine is full of useful chemical elements — nitrogen, phosphorus and potassium, all of which help plants grow. Kanye West knows it: his new compound in Wyoming will reportedly feature a “urine garden” nourished by the pee produced onsite. But what’s being dreamed up on this quiet French industrial estate is on a different scale altogether. The eco-entrepreneurs behind Toopi are calling for a “peevolution”: a wholesale reassessment of how societies think about urine. Far from flushing it down the drain and spending billions a year treating it, Toopi is part of a movement that hails pee as an extremely valuable resource – if only they can get their hands on enough of it.


Like all good origin stories, Toopi started with a frustrated portaloo manager. It was 2018, and Matthieu Préel was venting to his friend about how difficult it was disposing of the human urine he had on his hands. “He was telling me how annoying it was to have to pay all this money to dispose of all this pee,” says Michael Roes, Toopi’s co-founder. “[Préel] said to me, ‘Do you have an idea for something we could do with it?’”
Roes knew exactly what he could do with all that excess urine. Already the manager of a fertiliser company, he was well aware that it could be used to feed and nourish plants. The problem was that you needed vast quantities of pee. Urine contains just a fifth of the nitrogen found in a bottled fertiliser you might buy in a garden store, and less than five per cent each of the potassium and phosphorus, according to a chemical analysis by the French researcher Fabien Esculier.
Roes’ challenge was to turn urine into a fertiliser that could actually compete with industrial products. He began mixing urine with bacteria that he suspected would boost how much nitrogen, phosphorus and potassium from the pee that plants can access: azotobacter chroococcum, which helps crops assimilate nitrogen from the air, and lactobacillus plantarum, which helps the plants absorb nutrients and water. “It seemed to work,” says Roes. Pee, it turned out, was a great culture for these microorganisms.
The result was a kind of super-charged urine that, according to early testing, fares well alongside chemical fertilisers litre-for-litre, unlike pure, unadulterated pee. Tests done in collaboration with the National School of Agricultural Engineering in Bordeaux found that Toopi’s fertiliser helped corn plants grow 60 to 110 per cent more compared to a mineral fertiliser.


The company has just opened its first site near Bordeaux, a chipboard-lined office of a dozen people with a vast production area next door. That space is currently almost empty, except for the huge tankers of urine and a tent full of tomato plants undergoing tests. But Roes eventually wants to process one or two million litres a year here, in a process that involves warming the urine up in metal vats and shaking it around to help the bacteria grow. “Wine-makers add bacteria to grape-juice to transform it into something else. We’re doing the same thing — but with urine,” Roes says.
The dream of turning urine into fertiliser isn’t just a neat way to make the most of our waste – it could help relieve pressure on the environment, too. If we can unlock the plant-feeding potential of our urine, it could reduce our reliance on synthetic fertilisers, which currently help produce food for at least half of the world’s population. The problem is that nitrogen applied to fields often ends up flowing into waterways and feeding algal blooms — vast stretches of algae that mess up the ecosystems of lakes and rivers by drastically cutting the water’s oxygen supply.
“If you’re in an airplane and you go over any lake where there’s people living, you’re going to see these algal blooms at certain times of the year,” said Kim Nace, executive director of the Rich Earth Institute, a US-based nonprofit that researches ways to get more out of our waste. “A school of fish will swim into this water and just die because they don’t have enough oxygen,” Nace says.
The other big problem with our current way of feeding plants is that producing synthetic fertilisers requires a vast amount of energy. “We’re talking about one or two per cent of global energy use,” says Fabien Esculier, a researcher at the Ecole des Ponts ParisTech engineering school and pee evangelist who wears a pin-badge that says “Urine Is Cool”.


Esculier also points out that urine would be a more reliable source of phosphorus, which is extracted from mines in China, Russia and the disputed Western Sahara. Rather than dig fertiliser up from the ground, why not switch to a source of phosphorus that is present wherever there are humans?
Esculier and his colleagues have been testing a range of urine-based fertilisers, and although they’re yet to publish the results, he says that most of them are as efficient as their chemical alternatives. But urine is only one fix in the fight for a better way to farm. Run-off from urine-based fertilisers could also feed algal blooms. Nutrients leaking from our sewers into rivers is already a problem in the UK, part of a eutrophication problem that the government has already spent £2.1 billion trying to fix. “In my view it’s more about transforming agricultural practices and figuring out how urine could be used in new eco-farming methods,” he says.
Like Nace, Esculier is preoccupied with figuring out how humanity can better design its sanitary systems to recognise our urine for the amazing resource it is, diverting its nutrients before they hit the drain. Each human produces more than 450 litres a year. In the UK alone, that’s 30 billion litres of a valuable resource that we’re flushing away — using clean water, which is in ever-shorter supply.
The conundrum is how to get hold of the urine in the first place. Modern toilets flush everything down together, making it impossible to separate pee from poop. Swedish companies began developing designs that separate the two in the 1990s, and the German-made NoMix toilet followed around the turn of the millennium. Men didn’t like having to sit down to get the angle right, though, and the company eventually stopped making them.
Could the urine-diverting loo make a major comeback? Perhaps. Fancy Swiss bathroom brand Laufen gave the idea a swish update last year. “I actually think it’s better than a normal toilet,” says Kai Udert, a veteran of human waste research whose research institute, EAWAG, helped out with the design.
Toopi’s plans don’t necessarily depend on mass uptake of separating loos; they could source the pee for their fertiliser from urinals. But even then, they’d need a huge quantity in order to produce at scale. The company is in talks with anyone and everyone who might be able to supply it: medical labs, festivals, construction companies that have portaloos on their building sites. Most enticing of all is a potential partnership with the Stade de France, home of the national football and rugby teams. The stadium seats more than 80,000 fans, most of whom take a leak during their visit. Just think of all the piss!
The firm, which has has just raised €1 million (£908,000) in its first funding round, is developing five different liquid fertilisers which can be applied using existing farming methods, and, Roes says, are cheaper to use; the starter fertiliser for new crops costs about €40 (£36) per hectare, as opposed to €50 (£54) for the chemical stuff. Distributors have “several million litres” on pre-order, according to the company.
Currently, though, they’re producing virtually nothing. Before being allowed to launch on the market, Toopi has to submit its fertilisers to rigorous testing. They’re hoping to get the green light to start mass production next year. “France has some of the toughest regulations on fertilisers, so it isn’t easy,” said Roes. “But that means that once French authorities have given us the go-ahead, the product would be pretty much ready to go worldwide.”
One piece of good news for supporters of the peevolution came in January, when a study from the University of Michigan found that urine can be safely used as a fertiliser without fear of it fuelling the spread of antibacterial resistance, a previous concern. Regardless of whether or not Toopi ends up conquering the fertiliser market, Roes remains convinced that humanity’s future lies making much better use of our pee.
“The world is already running out of clean water,” he said. “And if water’s in short supply, I think we’d rather drink it than flush it down the toilet. That much is obvious.”
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