Biobricks, the environmentally friendly building substrate, are usually made from innocuous enough materials. Some sand, some mushroom filament, occasionally construction waste. And now, human waste.
Scientists at the University of Cape Town recently made the world’s first biobrick using human urine, and once you get past the initial ick factor, it’s not really as strange as it sounds.
The sand-based bricks are made through a process called microbial carbonate precipitation, which is a close cousin to how seashells are formed. As the scientists explain it, to make a urine brick they mix stabilized urine gathered from mens’ urinals with sand and a bacteria that produces the enzyme urease. This bacteria is able to break down the urea in urine and create a hard, calcified byproduct that cements the sand particles together in whatever shape they’re in.
Unlike traditional bricks, which require firing at temperatures upward of 2,500 degrees Fahrenheit, the team’s urine bricks can harden in a mold at room temperature, making them more energy efficient to produce.
The big discovery here is not the process itself—scientists in the U.S. have explored making biobricks with synthetic forms of urine for a while—but the fact that it was done with real, live human pee. Sure, a pee-enabled biobrick isn’t the most marketable of building materials, but it’s hard to deny it’s an unlimited resource.