Future homes could be made from bricks made of wee

Last updated at 07:52
From left: Dr Dyllon Randall and his students, Vukheta Mukhari and Suzanne Lambert holding the world’s first bio-brick made using human urineRobyn Walker/UCT

The yellow brick road could soon be a way to describe a street where homes have been built using 'wee bricks'.

Now, 'wee bricks' might not be a term you're familiar with and it's not the Scottish way of saying they're really small...

We literally mean bricks made from human pee. No kidding.

Students in Cape Town collected the urine from male toilets in their university department and mixed it with sand and bacteria.

Dr Dyllon Randall, Supervisor at the University of Cape Town says "It's essentially the same way that coral is made in the ocean."

The wee bricks, nicknamed 'bio-bricks' are environmentally friendly because normal bricks need to be baked in high-temperature kilns that produce large amounts of carbon dioxide.

The only downside, the process of making bricks from wee is much smellier.

A bottle of urine and a "bio-brick" mouldUCT
The bricks take between four and six days to grow depending on the strength and size needed

"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," The smelly gas, is then converted into nitrogen-rich fertiliser says Dr Randall.

After about 48 hours, the bricks completely lose their bad smell but need another couple of days to grow - if you want a stronger brick you leave it for longer.

To make a 'bio-brick', the students needed between 25 to 30 litres of wee and since humans produce up to 300ml on average per pee, it would take 100 toilet breaks to make a standard-sized brick, although the bricks can vary in shape and size.

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