The University of Cape Town (UCT) has unveiled the world’s first bio-brick grown from human urine – yes, pee.
The bio-brick was developed by UCT master’s student in civil engineering Suzanne Lambert.
“The bio-bricks are created through a natural process called microbial carbonate precipitation. It’s not unlike the way seashells are formed,” says Dr Dyllon Randall, Lambert’s supervisor.
In this case, loose sand is colonised with bacteria that produce urease. 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.
“This project has been a huge part of my life for the past year and a half, and I see so much potential for the process’s application in the real world. I can’t wait for when the world is ready for it,” Lambert says.
The bio-brick is also good for the environment and global warming as it is made in moulds at room temperature.
Regular bricks are kiln-fired at temperatures around 1,400°C and produce vast quantities of carbon dioxide.
UCT says Lambert and civil engineering honours student Vukheta Mukhari have been hard at work in the laboratory testing various bio-brick shapes and tensile strengths to produce an innovative building material.
Chemically speaking, urine is liquid gold, according to Randall. It accounts for less than 1% of domestic wastewater (by volume) but contains 80% of the nitrogen, 56% of the phosphorus and 63% of the potassium of this wastewater.
Some 97% of the phosphorus present in the urine can be converted into calcium phosphate, the key ingredient in fertilisers that underpin commercial farming worldwide. This is significant because the world’s natural phosphate reserves are running dry.
The fertilisers are produced as part of the phased process used to produce the bio-bricks.
First, urine is collected in novel fertiliser-producing urinals and used to make a solid fertiliser. The remaining liquid is then used in the biological process to grow the bio-brick.
At the moment, only urine from male urinals is collected because that’s socially accepted.
In the run-up to unveiling the bio-brick, both students expressed optimism about the potential of innovation in the sustainability space.
“Working on this project has been an eye-opening experience. Given the progress made in the research here at UCT, creating a truly sustainable construction material is now a possibility,” says Mukhari.
Randall says the work is creating paradigm shifts with respect to how society views waste and the upcycling of that waste.
“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.”