Scientists in South Carolina have this week described how astronauts of the future could recycle their own urine, breath and other forms of waste into useful products, such as fuel, nutrients, clean drinking water, and even polymer plastics.
In space, this makes perfect sense – there’s only so much room on a rocket to pack everything you need, so why not use genetically modified yeast to manufacture things on the fly? Urine contains useful nitrogen, and faeces is chock full of practical materials.
But why let interstellar flyboys have all the fun? If you want to follow Nasa and upcycle your waste, here are some of the treasures that could be uncovered from bodily trash.
Legal and illegal drugs
Synthetic biologists for years have used yeast and other microbes to produce vaccines and medicines such as insulin and penicillin. This means it could be possible to produce new drugs by feeding yeast with nutrients from urine, but hey, why stick to utilitarian drugs? In 2015 Canadian scientists unveiled genetically modified yeast strains that can convert simple sugars into opiates. Uppers and hallucinogens could be right around the corner. And why not? Life could get mighty boring on a Martian base, but it’s often a drag here on Earth.
Gold and other precious metals
Believe it or not, sewage is teeming with gold, silver, platinum, titanium and copper. It’s hard to know where exactly these precious metals are coming from – cosmetics and personal care products often carry them, but our food can as well: titanium dioxide is often added to junk food such as doughnuts. Scientists at the University of Arizona estimate that the annual waste from a million Americans contains $13m worth of metals. And given how our voracious appetite for metals is causing environmental and social disaster, the least we could do is reduce the impact of our smartphone addiction by shifting through our own shit for the metals to make them.
Carbon-neutral bricks
In 2011 researchers at Yorkshire Water and Leeds University unveiled a method for combining incinerated sewage with ash to produce carbon-neutral bricks. So there, the answer to all our green construction needs: set your faeces on fire.
Transport fuel
For years scientists have proposed using anaerobic digesters on spacecraft or lunar bases to produce methane – a potent fuel – from astronaut’s faeces and urine. The future is finally here as Bristol’s GENeco Bio-Bus makes sure “waste isn’t wasted” by using biogas produced from domestic waste. Why not scale up across the UK? To be frank, at this point even a river of sewage couldn’t worsen conditions on beleaguered Southern rail …
Livestock feed
Researchers at the Sanitation Ventures group at the London School of Hygiene & Tropical Medicine have been developing ways for the 2.5 billion people globally who lack proper latrines to put their waste to good (and safe) use. One of the best ideas: feeding faeces to black soldier fly larvae, which can then ground into feed for chickens or fish. If eating chickens fed on what started as your own excrement might sound revolting, spare a thought for those American astronauts whose drinking water is purified urine.
Electricity
Microbial fuel cells already exist that can easily generate electricity by using urea as fuel. The largest “Pee Power” urinal built was on show next to the Pyramid Stage at Glastonbury, to showcase a technology intended for disaster areas and refugee camps. No reason it couldn’t be part of the greater urban infrastructure though – researchers at Caltech are creating solar-powered urinals to generate hydrogen fuel.
Whatever way we choose to upcycle our waste, one thing is clear: the absolute stupidest thing we could do with our excrement is to use clean water to flush it away, and then spend a fortune to treat it all over again.