World’s first brick made with human urine unveiled in South Africa

The world’s first bio-brick made using human urine was unveiled this week
UCT/Robyn Walker
Katy Clifton26 October 2018

The world’s first brick created with human urine has been developed by students in South Africa.

Urine was combined with loose sand and bacteria by master’s student Suzanne Lambert at the University of Cape Town (UCT).

The university has been harvesting urine from men’s toilets to make what they are calling the world’s first “bio-brick”.

Supervisor of the project Dr Dyllon Randall said that the process, called microbial carbonate precipitation, is not unlike the way seashells are formed.

The process involves loose sand being colonised with bacteria to produce urease. The urease breaks down the urea in urine while producing calcium carbonate through a chemical reaction.

This cements the sand into any shape, including the world’s first rectangular building brick grown from human urine.

Civil engineering student Ms Lambert said: “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,” she added.

Bio-bricks initially smell of ammonia but the odour disappears after about 48 hours, according to the university.

The concept of using urea to grow bricks was tested in the United States a number of years ago using synthetic solutions, but Ms Lambert’s brick uses real human urine for the first time.

This will have significant benefits for waste recycling and upcycling, a UCT spokesman said.

Ms Lambert's work builds on foundational research by Jules Henze, a Swiss student who spent four months working with Mr Randall on this concept in 2017.

Bio-bricks are environmentally-friendly as they are made in moulds at room temperature, where regular bricks are kiln-fired at around 1,400°C and produce vast amounts of carbon dioxide.

For the past few months, Ms Lambert and civil engineering honours student Vukheta Mukhari have been working at testing various bio-brick shapes and tensile strengths to produce a building material.

The strength of the bio-bricks would depend on client needs.

“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,” Mr Randall said.

“The longer you allow the little bacteria to make the cement, the stronger the product is going to be. We can optimise that process.”

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.

The overall scheme would effectively result in zero waste, with the urine completely converted into three useful products, UCT says.

Mr Mukhari said: “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.”

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