Astronauts will soon turn their urine into drinking water and fuel instead of ejecting it out into space.
Nasa-funded research, published in the journal ACS Sustainable Chemistry & Engineering, has shown how urine can become an essential source of drinking water if something were to wrong or supplies run low.
Scientists Eduardo Nicolau and Carlos R. Cabrera say their findings have the potential to catalyse new ways to treat municipal waste water.
Nicolau and his colleagues used a wastewater treatment process called forward osmosis coupled with a fuel cell. They found that put together, they can generate power.
Using this, they collected urine and shower wastewater and processed it using forward osmosis, which filters contaminants from the waste.
Their creation, called the Urea Bioreactor Electrochemical system, was able to efficiently convert the urea into ammonia in the bioreactor, then turn the ammonia into energy with the fuel cell.
At present, urine is sent out into space. On long-term journeys, it makes up about half of a mission's total waste.
Recycling it, the scientists say, is essential to keeping a clean environment for astronauts. It would also save millions in having water sent up from Earth if supplies ever did run low.
While designed for space, the authors conclude: "The results showed that the UBE system could be used in any wastewater treatment systems containing urea and/or ammonia."