Researchers Create Bio-Bricks Out of Urine
Researchers from the University of Cape Town’s civil engineering program have created the first bio-brick grown from human urine, signaling progress in innovation.
The bricks are created through a natural process called microbial carbonate precipitation, which is similar to how seashells are formed, according to Dyllon Randall, a senior lecturer in water quality engineering.
“In this case, loose sand is colonized with bacteria that produce urease,” the university said in a press release. “An enzyme, the urease breaks down the urea in urine while producing calcium carbonate through a complex chemical reaction. This cements the sand into any shape, whether it’s a solid column, or now, for the first time, a rectangular building brick.”
For the past few months students have not only been creating the bricks, but also testing various shapes and tensile strengths.
“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,” said Randall.
“The longer you allow the little bacteria to make the cement, the stronger the product is going to be. We can optimize that process.”
Not only do the bio-bricks produce less carbon dioxide (they are made in molds at room temperature instead of being kiln-fire), but their byproducts (nitrogen, phosphate and potassium) can also be used as components for commercial fertilizers.
Those fertilizers are produced as part of the phased process used to make the bricks, the university says, ultimately resulting in a zero-waste process.
The next question is how to optimize the process and make it profitable with the obvious logistic hurdle of urine collection.
“At the moment we’re only dealing with urine collection from male urinals because that’s socially accepted,” Randall said. “But what about the other half of the population?”
Ultimately, though, the work should impact how society views waste and the upcycling of that waste, Randall continued.
“In this example you take something that is considered a waste and make multiple products from it. You can use the same process for any waste stream. It’s about rethinking things.”