There’s an entirely new environmental reason to let it mellow if it’s yellow: According to a report in The Guardian, students in South Africa have created the world’s first brick made from human piss. “The bio-brick was produced by students from Cape Town, who collected urine from specially designed male urinals at the university’s engineering building and mixed it with sand and bacteria,” writes Rebecca Ratcliffe.
Dyllon Randall, the senior lecturer in water quality engineering at the University of Cape Town who supervised the project, told The Conversation that the bio-brick is made by a process called microbial induced calcium carbonate precipitation, which involves increasing the pH of the urine to keep the pee fresh during the collection or storage. “This initial process also produces a solid fertiliser, calcium phosphate. This is removed from the liquid phase by filtration, and we’re left with a solution that’s rich in urea which can be used to make bio-bricks,” Randall explained.
Suzanne Lambert, a master’s student at the university and another one of the bio-brick’s developers, told NBC News that the process is similar to how marine organisms help form coral reefs, which are also made of calcium carbonate. It’s “how biology has been building structures for millions of years,” she said.
Apart from the obvious bonus of building material out of recycled human urine via a process that produces zero waste, another advantage to these piss-bricks is that while normal bricks need to be baked in high-temperature kilns (2,552 degrees) that produce large amounts of carbon dioxide, these bio-bricks don’t require any heat. “If a client wanted a brick stronger than a 40 percent limestone brick, you would allow the bacteria to make the solid stronger by ‘growing’ it for longer,” Randall told The Guardian. “The longer you allow the little bacteria to make the cement, the stronger the product is going to be. We can optimise that process.”
If you’re thinking, that sounds fine and good but what about the fact that piss smells like, well, piss, don’t worry — according to Randall, they will be stinky at first because of the smell of ammonia, but that stench will disappear after a few days. “Importantly, the bio-bricks lose their ammonia smell after drying at room temperature for a day or two and are safe to use and handle thereafter,” Randall told The Conversation. As for whether we can expect these piss bricks to be used at scale, Randall tells me that it’s too early to answer those questions, since they’ve only been working on this project for a year.
The real question here, of course, is what the intended end users of these bricks make of all this. I reached out to Swedish Woodworks, a construction company in L.A., where Peter, one of the employees, seemed skeptical about the entire idea. “I don’t think I would be making bricks out of urine,” he says. “Especially in Los Angeles, all the homes are mainly built with wood, stucco and concrete. It’s just cheaper.” Still, he admits that in places like Texas, where stucco costs more than double what brick costs, it could be a possibility, since brick requires less maintenance.
In other words, as young people wait longer and longer to buy their first home, it’s very possible that said first home will end up being built from piss.
Sounds about right.