Pee Could Help Future Settlers on Mars Grow Vegetables

  • You get fertilizer for your fresh veggies straight from your toilet. What’s not to like?

Imagine you were going to move to Mars. What would the main issue be? Aside from no oxygen, extreme temperatures, constant risk of explosive decompression, or the secret alien base that’s totally there.

We’re talking about food. You would have whatever you brought with you and… Well, that’s pretty much it.

Mars isn’t exactly an agricultural wonderland. With an atmosphere that’s 95% oxygen and water that may or may not be there, it’d be kind of hard to grow, say, potatoes for dinner.

But now a team of researchers from the Tokyo University of Science might just have overcome one hurdle standing in the way of interplanetary farming. They’ve come up with a “cheap and efficient” liquid fertilizer that could help with agriculture in extreme environments

At the same time, it would solve an important waste treatment issue. And that’s because it’s made out of your pee.

“I’m hungry and I really need to pee. Jackpot!”

Learn from History

Led by Junior Associate Professor Norihiro Suzuki, the science team aimed to solve the problem of producing food in an enclosed environment. That doesn’t necessarily mean a Mars base, either – their solution could help settling other inhospitable places, like the Antarctic.

“The researchers here hope to spearhead the technological development for safe and sustainable space agriculture-with the aim of sustaining humans for a long time in an extremely closed environment, such as a space station,” the Tokyo University said.

To open up the doors to an agricultural future, Suzuki and his team looked to the past. For millennia, people have been using animal waste to fertilize their fields.

Although we the people don’t care much for either, plants love both poop and pee. Bodily waste is rich in nitrogen, a vital nutrient for practically every kind of flora.

So, thinking about how to get nitrogen on an isolated space station, Suzuki’s team had their “Eureka!” moment. The staff of the station still needs to go to the bathroom, so why not use their waste to supply plants with nitrogen?

At the same time, they would address the critical issue of space waste management. Without a powerful solution, any possible Mars space would soon be swimming in sewage.

It’s a win-win, really. You get rid of your pee, and you get to eat delicious pee-grown vegetables!

Electrochemical Pee Science

But in order for the plan to work, there needs to be a functional, cost-effective method of transforming pee into fertilizer. And that’s just what Suzuki and his team have created.

“This process is of interest from the perspective of making a useful product, i.e., ammonia, from a waste product, i.e., urine, using common equipment at atmospheric pressure and room temperature,” Suzuki said.

The team successfully developed an electrochemical method to derive ammonium ions, which are used in standard fertilizers, from human pee. The beauty of the process is that – as Suzuki said – it doesn’t need a specialized high-pressure chamber or any other purpose-built space.

The researchers’ experimental setup is actually deceptively simple. On one side, it has what they called a reaction cell, comprising a boron-doped diamond (BDD) and a light-inducing catalyst, made of titanium oxide.

Opposite that, they had a counter cell, which includes a “simple platinum electrode.” They passed an electrical current from the counter cell to the reaction cell through a container of urea.

As the electricity surged through the urea, it formed the sought-after ammonium ions. Originally, the tests were run without the catalyst, but it was added once the team realized that light helped produce more ammonium ions.

Destination: Human Urine

Granted, the tests Suzuki’s team has performed so far used urea, and not actual human pee. But don’t worry, that’s what they’re planning to try out next!

“We are planning to perform the experiment with actual urine samples, because it contains not only primary elements (phosphorus, nitrogen, potassium) but also secondary elements (sulfur, calcium, magnesium) that are vital for plant nutrition,” Suzuki explained.

While an actual Mars mission is still probably a long time coming, Suzuki is positive that his team’s discovery will help make the dream of settling the Red Planet reality. He believes that their method provides “a solid basis for the manufacture of liquid fertilizer” in extreme agriculture.

“It will turn out to be useful for sustaining long-term stay in extremely closed spaces, such as space stations,” he said confidently.

Growing your food with your own waste products doesn’t sound like the most appetizing idea. But like they say, beggars can’t be choosers, and future hungry Mars-tronauts will definitely be thankful for the Suzuki team’s efforts.