Two local scientists have designed a way to turn human urine into highly durable bricks that could wind up being the future of sustainable building.
The world-first innovation – created by civil engineering master's student Suzanne Lambert and honours student Vukheta Mukhari – was unveiled last week.
Dr Dyllon Randall, who is senior lecturer in water quality engineering and Lambert's thesis supervisor, explains that similarly to the way that seashells are formed, bio-bricks made from urine are created through a process known as microbial carbonate precipitation.
Chemically speaking, human urine is known as liquid gold.
When urine is combined with loose sand, it produces a bacteria called urease, which is what breaks down the urine and produces calcium carbonate through a complicated chemical reaction. Eventually, this process cements the sand into any shape – in this case, and for the first time, in the shape of a building brick.
The innovation – which uses human urine for the first time – is being hailed as the future of sustainability because the bio-brick process produces nitrogen and potassium as bi-products, which form important components of commercial fertilisers.
"Some 97% of the phosphorous 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," says Randall.
Mukhari and Lambert say they are both full of excitement over the potential this innovation has on the sustainable construction sector globally.
"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.
Mukhari adds: "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."