Tag Archives: urea

Urine, the future material to build new bases at the moon

The Apollo lunar flights ended in 1972 but interest in the moon and the possibility of going back is still going strong. NASA hopes to send astronauts to the lunar South Pole by 2024, working with commercial and international partners.

Credit NASA

Doing so raises many logistical questions, such as the establishment of a base for the astronauts. Sending materials to the moon to build a base can be expensive and difficult, however, so space agencies are investigating new approaches, including the use of urine.

In a new study, researchers have found that urea, the major organic compound found in human urine, could be useful for making concrete for lunar structures. Its use could make them less brittle and more flexible, and resulting in hardier buildings.

“The two main components of urine are water and urea, a molecule that allows the hydrogen bonds to be broken and, therefore, reduces the viscosities of many aqueous mixtures,” said materials scientist Ramón Pamies of the Polytechnic University of Cartagena in Spain.

Pamies and a group of researchers from Norway, Spain, the Netherlands, and Italy conducted a number of experiments testing the use of human urea as a plasticizer. To do so, they used a material developed by the European Space Agency similar to lunar regolith.

They tested this material with urea and with other plasticizers, seeing how much weight it could support. They first tested its resistance after heating the material to 80ºC (176 ºF), followed by repeatedly freezing and thawing it. This was meant to see if the material would endure weather conditions at the moon, where temperatures can vary from 120º C (250º F) during the day to -130°C (-208°F) at night. Any building materials there would have to withstand significant thermal change while still insulating the interior.

Thankfully, the tests showed promising results. The urea that was used as a plasticizer could support heavy weights, remain stable, and keep its shape despite the harsh weather. Nevertheless, there are still challenges ahead before we’ll be able to actually use the urea.

“We have not yet investigated how the urea would be extracted from the urine, as we are assessing whether this would really be necessary, because perhaps its other components could also be used to form the geopolymer concrete,” Anna-Lena Kjøniksen, one of the researchers from the Norwegian university, said in a statement.

The study was published in the Journal of Cleaner Production.

Urine Brick.

Bricks grown from your urine make for greener houses, plumper crops

University of Cape Town (UCT) researchers want to make cheaper fertilizers and greener buildings — using your toilet.

Urine Brick.

(From the left) UCT’s Department of Civil Engineering’s Dr Dyllon Randall and his students, Vukheta Mukhari and Suzanne Lambert, holding the newly-unveiled bio-brick.
Image credits University of Cape Town.

Building materials like concrete, steel, or bricks are quite energy-intensive to produce. Since most of this energy is produced in fossil-fuel plants, it has a sizeable carbon footprint. Emissions associated with fuel use and those released by certain chemical processes during manufacture add to these products’ overall carbon footprint.

But, if you’re looking for a more eco-friendly alternative for all your masonry pursuits…

Urine luck

A team led by Suzanne Lambert, a civil engineering master’s student at the UCT, unveiled the first bio-brick developed from human urine. The material is created through microbial carbonate precipitation, a process similar to that used by marine creatures to build their shells.

It largely involves strengthening sand with chemicals derived from urine. The sand is colonized with bacteria that produce urease (an enzyme that breaks down urea in urine. The resulting calcium carbonate binds the grains of sand together, creating a very solid object in virtually any shape. It has to be mentioned, however, that sand is becoming an increasingly scarce material.

The concept of using urea for bricks isn’t exactly new — it was first tested in the U.S. a few years ago. However, Lambert’s team is the first one to use human urine, not synthetic solutions, for the process. This isn’t the first bio-brick to be developed, nor the first solid brick based on simple materials — but they do come with a wide range of bonuses that make them stand out.

One of the best parts of the new bricks is that they’re fabricated in molds at room temperature. This drastically reduces their emission levels compared to regular bricks. The fabrication process can also be tweaked to address particular needs — lower production times (and thus, costs), or higher-strength.

“If a client wanted a brick stronger than a 40 percent limestone brick, you would allow the bacteria to make the solid stronger by ‘growing’ it for longer,” said Dr. Dyllon Randall, a senior lecturer at UCT and Lambert’s supervisor. “The longer you allow the little bacteria to make the cement, the stronger the product is going to be. We can optimise that process.”

Brick the houses, sow the fields

Bio-bricks could also, surprisingly, help us grow plumper crops. Urine is rich in several chemical compounds that are key ingredients in fertilizers: nitrogen, potassium, and phosphorus (we’re running low on virtually every one of those compounds). Chemically speaking, Dr Randall adds, urine is liquid gold. Although it accounts for under 1% of domestic wastewater by volume, it provides 80% of the nitrogen, 63% of the potassium, and 56% of the phosphorus in wastewater. Nitrogen is particularly important from an agricultural point of view.

Most of these compounds can be harvested from wastewater, the team adds. Some 97% of the phosphorus present in urine, for example, can be recovered and used for fertilizers.

Virtually nothing is wasted when producing these bio-bricks, the team writes. The process starts with urine collected from novel fertilizer-producing urinals. Here, it’s used to create a solid fraction (which is basically a fertilizer mix). The liquid fraction is then used to grow the brick themselves.

“In that process, we’re only after two components: carbonate ions and the calcium. What we do last is take the remaining liquid product from the bio-brick process and make a second fertiliser,” Dr Randall explains.

The main hurdle the team has to overcome is logistics — namely the collection and transport of urine to processing facilities. How society reacts to the idea is another hotbed for discussion. Right now, the team is only dealing with urine collection from male urinals “because that’s socially accepted,” says Dr Randall. However, that leaves “half of the population” out of the process, which is a shame.

Still, Dr Randall hopes that their work will help people reconsider their relationship with waste — of any kind.

“In this example you take something that is considered a waste and make multiple products from it. You can use the same process for any waste stream. It’s about rethinking things,” he said.

Pee, Poop, and Perspiration Will Be Useful in Traveling to Mars

People have effectively been able to acquire fuel and, consequently, energy from human urine. This capability has been known for a number of years. In late 2012, a small group of teenage girls from Nigeria made the news by presenting a generator that ran on urine at the Maker Faire Africa. In their generator, the pee is poured into an electrolytic cell where the hydrogen is isolated from other components in the liquid.

The hydrogen is then purified by passing through a filter. From there, it’s sent to a gas cylinder from which it is further pumped into a cylinder containing liquid borax. The borax aids in separating the hydrogen gas from any remaining moisture. The final step is for this gas to be sent to the generator. The girls’ machine was able to supply six hours’ worth of electricity by using a mere liter of liquid waste.

Of course, this was a rather simple apparatus primarily for display, but the important thing is it worked! Urine’s use for producing gas and/or syngas (synthesis gas) has the potential to be quite revolutionary.

Waste as a Water Source in Space


Credit: Wikimedia Commons.

Recycling everything possible in extraterrestrial day-to-day life and travel saves both space and money. For a while now, astronauts on the International Space Station have been recycling their own perspiration and pee. The purified output is clean water, which is drunk a second time over. This cycle can be repeated over and over.

You’ve heard of twice-baked potatoes? Well, twice-expelled waste is starting to catch up in its popularity. Human urine and condensate (including breath moisture, human sweat, shower runoff, and animal pee) are all distilled and reverted to clean drinking water. As of 2015, about 6,000 extra liters of water are recycled each year.

Waste Empowering Yeast

One of the molecules which makes up our urine is called urea. Furthermore, urea is composed of nitrogen and carbon. Both of these chemicals are needed to feed a yeast, Yarrowia lipolytica, which when genetically tweaked properly can take a variety of forms such as bioplastics and even fatty acids. One particular fatty acid necessary for human health and functionality is Omega-3. The brain requires this nutrient.

Thus, Yarrowia lipolytica is being tested to hopefully be able to produce Omega-3’s efficiently in the future. This would be a great aid to humanity in the occasion of a manned mission to Mars or elsewhere. In addition, future astronauts will use 3D printers onboard their spacecraft to generate tools and other needed objects made of plastic. Yet again, the yeast can be altered to produce a certain type of polyester which could be employed for this purpose.

Feces and Urine for Future Food

The sheer quantity of food needed to sustain a manned mission to Mars remains a big problem. However, a clever party of researchers from Pennsylvania State University believes to have found an efficiently ingenious answer. The concept was discussed in a paper published in late 2017. Their space-saving device, a bioreactor, uses the urine as well as the feces of astronauts to feed a non-harmful bacteria that, in turn, is capable of sustaining the human space travelers.

Within the bioreactor, the solid and liquid waste become condensed leaving salts and methane gas in its place. It’s the methane which is used to grow the microbial mush, an edible element with a texture similar to that of Vegemite, a thick Australian spread made up of leftover brewers’ yeast extract along with an assortment of additives.

As you have seen, our astronauts’ waste will not be wasted. Scientists will surely engineer more ways for bodily waste to be put to beneficial use.