Urine bricks: human waste used to create sustainable building blocks

O From all the ambitious ideas that could deliver us from the wrath of climate change, turning human urine into liquid gold seems like a long shot. But according to South African scientists, it turns out that the ubiquitous fluid contains an essential ingredient that could help us in various ways, including, oddly enough, a way to rebuild our cities as rising tides invade coastal communities.

On Wednesday, a team from the University of Cape Town revealed that human urine could be manipulated in a solid, brick-like form called "organic brick." Unlike ordinary baked bricks, organic bricks do not require intense heat. their production does not release thousands of kilograms of greenhouse gas from carbon dioxide.

Professor Dyllon Randall, Ph.D., water quality engineer, discovers the potential of urine after beginning to place makeshift urinals around the university in the purpose of making fertilizer. . Urinals contain building lime, which reacts with phosphorus in the urine to produce fertilizer.

But even after the fertilizer extract, Randall quickly realized there was still some fluid left. This, to use his words, was his "liquid gold".

In the remains, there was an important compound called urea, which one naturally finds in the Human urine. Randall discovered that the urea solution could be used to make a brick by mixing it with loose sand colonized by species of bacteria producing the enzyme urease.

Urease secreted by the bacterium breaks down urea and, as a bonus, produces the compound calcium carbonate. This hard white compound, which forms the bulk of the eggshells and shells of molluscs and crustaceans, solidifies sand particles in bricks.

The longer the bacteria have enough time to act, the stronger the bricks, the team explains, suggesting that this method would create several types of building materials.

"No one has examined the situation in terms of the complete cycle and the possibility of recovering several valuable products. The next question is how to do this in an optimized way to generate a profit from the urine, "Randall said.

This process, known as microbial carbonate precipitation, is not entirely new. Previous research has shown that there are many microorganisms capable of carrying out the process. What seems to be a novelty is that the team has finally found a use for a liquid that exists in unlimited quantities. This is a chance because the BBC estimates that it would take about 100 aisles to the toilet to produce one of these bricks.

The bricks at l 39 Urine does not require any burning procedure, but the team will have to speed up their process considerably before they can be a real alternative. At the moment, it takes between two and six days to grow depending on the desired strength and the team has not yet tried to build with them.

But for now, Randall is upset by the receipt of his product.

"I am grateful for people's open-mindedness and acceptance of these innovative technologies," said Randall in a video interview . "Who could have thought of collecting fertilizer in the urine or making organic bricks with this same urine? This kind of interest gives me a lot of hope for the future in terms of sustainable development and environment.