We spoke to the graduate student who made bricks from human pee

Pee contains quite surprising information. Scientists have known for nearly a decade that it is possible to produce bricks from bacteria, sand and urea, a chemical found in the urine. The researchers went ahead and produced these bricks, for the first time with human pee.

The South African engineer Dyllon Randall of the University of Cape Town, which qualifies the urine of "liquid gold wastewater" because of its chemical content, studied various uses of the pee and its components. A graduate student from her laboratory, Suzanne Lambert, unveiled bricks as strong as clay bricks, produced with human pee in a process called "microbial carbonate precipitation".

Basically, they start with sand-containing bacteria that produce an enzyme called urease. The urease eats urea in the pee and produces calcium carbonate, by sticking the sand in place.

But why pee bricks? According to the press release from the University of Cape Town, they are better for the environment as they can be trained at room temperature. On the other hand, the baked bricks must be heated to 1400 ° C and produce a lot of carbon dioxide. Plus, it's definitely a better use of your pee than what you are currently doing with it.

We discussed with Lambert the manufacture of pee bricks

Gizmodo: Where did you get this idea?

Suzanne Lambert: My supervisor spoke with him about how to make fertilizer from urine … But he discovered that urea did not hydrolyse [breaking down with the help of water]. He was researching what to do with urea and had founded a company that used synthetic urea to produce bricks. So, why not use urea in the urine to do the same thing?

G: How do you collect urine?

SL: There is a bathroom for boys in front of the laboratory. We have a makeshift urinal – a can with a urinal fixation at the top. You can detach the urinal to store urine. I just asked the boys at the university to kindly donate me.

G: And what does the texture of bricks look like? Are they as strong as normal bricks?

SL: The texture is similar to that of normal bricks. They are a little gray. And they are as strong as bricks. The last test I did, I brought them to 2.5 MPa (megapascals). There is an undergrad student who has done tests and he has had one up to 5MPa. a clay brick can withstand about 3MPa. It's pretty good. [ Author's note: A military submarine should withstand 5 MPa at 500 m depth .]

G: How does it become so solid?

SL: The idea is to imitate something that happens in nature. Take the way the coral is formed. Coral has bacteria on it. Bacteria produce an enzyme that reacts to produce calcium carbonate. I grow bacteria and put them in a mixture of sand, then the bacteria colonize there when you pump the urine. The bacterium produces an enzyme that converts urea to carbonate and ammonia.

G: Do people find this strange?

SL: Some people think so. Most people are just interested. You can change the waste concept of the population and how we reuse our waste that would otherwise be incinerated in a wastewater treatment plant. This is fine.

G: Do you think people will buy for this? How do you intend to change their perceptions?

SL: First, this kind of thing requires putting an idea in people's brains and showing them that the bricks do not smell. It's an interesting process, and there are so many other applications of these bacteria. This could be cheaper than most current methods. Hope that the need will provide the change. It may take a little while before it's applicable in our real world, but it's not that far. Maybe he can absorb part of the market. I am not sure. You can only hope.

[University of Cape Town]