A team of researchers from the University of Cape Town in South Africa have found a way to create bricks from human urine. Awesome! Wait, yuck!
Clay bricks have been a mainstay of the construction industry since at least 4000 BC. Traditional bricks are generally composed of lime, clay-bearing soil, sand or concrete and producing them leaves behind vast quantities of carbon dioxide.
A research team led by Suzanne Lambert, a Master’s student in civil engineering, have devised a way to create “bio-bricks” through a process very similar to how coral reefs and seashells are formed.
“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,” Lambert told University of Cape Town News. “I can’t wait for when the world is ready for it.”
The scientists first installed a special fertiliser-making urinal in the men’s room at the University. The processed urine was then collected and mixed with sand and a bacteria strand that produces an enzyme called urease.
The function of urease is to break down urea – a key component of urine – to produce a compound that cements the sand particles together and creates a grey-coloured brick as hard as, or even stronger than, a traditional brick.
“If a client wanted a brick stronger than a 40% limestone brick, you would allow the bacteria to make the solid stronger by ‘growing’ it for longer,” said project supervisor Dr Dyllon Randall, a senior lecturer in water quality engineering.
“The longer you allow the little bacteria to make the cement, the stronger the product is going to be. We can optimise that process.”
The bricks can be moulded in any shape, and have the added perk of being environment-friendly. They take six days to grow, and the longer the process the stronger the brick is.
In addition, the whole process produces nitrogen and potassium as by-products, which can be used to produce commercial fertilisers.
A brick made of urine sounds yucky, but they are said to pose no health risk. The only downside is that these initially give off a strong ammonia smell that wears off after a few days.
“Say you had a pet and it peed in the corner, and you have that strong smell – that’s ammonia being released. This process produces ammonia as a by-product,” Randall told the BBC.
Each bio-brick needs between 25 and 30 litres of urine to be produced. Considering that the average person produces between 200ml and 300ml of urine in each trip to the bathroom, that means it takes around 100 toilet visits per brick.
The idea of using urea to create bricks was previously tested in the US using synthetic solutions, but this new bio-brick is the first to use real human urine. It is an advancement that could entail dramatic changes in the way we conceive and build the future.
“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,” said Randall.
[Images courtesy of University of Cape Town News and Pexels]