University of Cape Town: World’s First Brick Grown From Human Urine
Students at the University of Cape Town have developed a bio-brick that mixes sand, bacteria and human urine. It’s the world’s first bio-brick grown from human urine.
The formation of the bio-brick
The bio-brick was developed by UCT master’s student in civil engineering, and was “created through a natural process called microbial carbonate precipitation. When urine is mixed with sand and bacteria, the resulting chemical reaction produces calcium carbonate, which hardens the mixture and forms the brick.
“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.”
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. “Each brick requires about 25 to 30 liters of urine, or roughly 100 bathroom trips, and is collected from a fertilizer-producing urinal. The by-product of the brick making process is used again to create a second fertilizer.”
Advantages of the bio-brick
- The technique makes something useful out of waste. “You take something that is considered a waste and make multiple products from it” said Dr Dyllon Randall. “You can use the same process for any waste stream. It’s about rethinking things,” he added.
- The bio-brick is good for the environment and global warming as it is made in moulds at room temperature. The brick doesn’t require the heat needed for traditional brick making
- The bio-brick is zero waste and has great potential to become a sustainable construction material. “In this example
- calcium phosphate: about 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.
