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The world's first bio-brick made using human urine was unveiled at UCT this week. In picture are from the Department of Civil Engineering Dr. Dyllon Randall and his students, Vukheta Mukhari and Suzanne Lambert. Credit: University of Cape Town
The world's first bio-brick grown from human urine has been unveiled by University of Cape Town (UCT) master's student in civil engineering Suzanne Lambert, an innovative paradigm shift in waste recovery.
The bio-bricks are created through a natural process called microbial carbonate precipitation. It's not unlike the way seashells are formed, said Lambert's supervisor Dr. Dyllon Randall, a senior lecturer in water quality engineering.
In this case, loose sand is colonized with bacteria that produce urease. An enzyme, the urease breaks down the urea in urine while producing calcium carbonate through a complex chemical reaction. This cements the sand in any shape, whether it is a solid column, or now, for the first time, a rectangular building brig.
For the past few months Lambert and civil engineer honors student Vukheta Mukhari have been hard at work in the laboratory testing various bi-brick shapes and tensile strengths to produce an innovative building material. Mukhari is being co-supervised by Professor Hans Beushausen, also from the civil engineering department. Beushausen is helping to test the products.
The development is also good news for the environment and global warming is bio-bricks are made in molds at room temperature. Regular bricks are kiln-fired at temperatures around 1400 ° C and produce large quantities of carbon dioxide.
The strength of the bio-bricks would depend on customer needs.
"If a customer wanted a brick stronger than a 40 percent limestone brick, you would allow the bacteria to make it stronger by 'growing' it for longer," said Randall.
"We can optimize that process."
Foundational work
The concept of using urea to grow bricks has been tested in the United States. Her work builds on the foundational research by Jules Henze, a Swiss student who worked with Randall on this concept in 2017.
"It's what I love about research." Said Randall.
Fertilizers as by-products
In addition, the nitrogen and potassium nitrogen and potassium products, which are important components of commercial fertilizers.
Chemically speaking, urine is a liquid gold, according to Randall. It accounts for 80 percent of the nitrogen, 56 percent of the phosphorus and 63 percent of the potassium of this waste water.
Some 97 percent of the phosphorus present in the urine can be converted into calcium phosphate, the key ingredient in fertilizers that underpin commercial farming worldwide. This is important because of the world's natural phosphate reserves are running dry.
Zero waste
The fertilizers are produced as part of the phased process used to produce the bio-bricks.
First, urine is collected in a novel fertilizer-producing urinals and used to make a solid fertilizer. The remaining liquid is then used in the biological process to grow the bio-brick.
"But in that process, we're only after two components: carbonate ions and the calcium." What we do last is taking the remaining liquid product from the bio-brick process and make a second fertilizer, "he explained.
The overall scheme would effectively result in zero waste, with the urine completely converted into three useful products.
"The next question is how to make it so much better that it can be created from urine."
There are also logistics to be considered; collection and transport to a resource recovery. Randall has discussed these opportunities in a recent review paper on urine. Another of his master's students is investigating the transport logistics of urine collection and treatment with some very promising results.
Social acceptance is another consideration.
"But what about the other half of the population?"
In the run-up to unveiling the bio-brick, both students expressed optimism about the potential of innovation in the sustainability space.
"This project has been a huge part of my life for the past year and a half, and I can not wait for it in the world." said.
"Working on this project has been an eye-opening experience," said UCT, creating a truly sustainable construction material is now a possibility, "Mukhari added.
Randall said the work is creating paradigm shifts with respect to how society views waste and the upcycling of that waste.
"In this example, you may think that it is a waste and make multiple products from it." "It's about rethinking things," he said.
Explore further:
Nutrient recovery from biowaste for mineral fertilizer production
More information:
J. Henze et al. Microbial induced calcium carbonate precipitation at elevated pH values (> 11) using Sporosarcina pasteurii, Journal of Environmental Chemical Engineering (2018). DOI: 10.1016 / j.jece.2018.07.046
C. P. Flanagan et al. Development of a novel nutrient recovery urinal for on-site fertilizer production, Journal of Environmental Chemical Engineering (2018). DOI: 10.1016 / j.jece.2018.09.060
D.G. Randall et al. Urine: The liquid gold of wastewater, Journal of Environmental Chemical Engineering (2018). DOI: 10.1016 / j.jece.2018.04.012
