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Converted Human
Waste Food for Astronauts
Scientists Working on
Converting Human Waste Into Food for Astronauts
BY NATHAN CHANDLER
A
manned mission to Mars might take around six months.
Suffice
it to say, when mealtime rolls around, astronauts won't be dial up
delivery pizza en route.
Instead,
they may be eating nutrition derived from their own fecal matter, a
concept that would save on cargo space and weight while maximizing materials
already found on the spacecraft.
At
Penn State University, scientists are developing a system that leverages
certain types of microbes that convert human solid waste into protein- and
fat-laden foods.
Researchers,
for better or worse, have already called the result a "microbial goo"
that's sort of reminiscent of Vegemite, a comparison that seems unlikely
to please the food product's corporate executives.
Because
it's difficult and time-consuming to grow food in space, astronauts have to
rely on items in their closed environment.
The
linchpin of the system is anaerobic digestion, which can break down
certain materials without the need for oxygen. It's a common process for
reducing municipal waste on Earth.
In
tests, the digestion process produced methane gas.
That
gas turns out to be useful in growing a microbe called Methylococcus
capsulatus, which is already used for animal feed pellets, that's
about 52 percent protein and 36 percent fat content.
According
to the National Academy of Sciences, humans function best when they ingest
nutrition with about 50 percent carbohydrates, 20-35 percent fat and 10-35
percent protein, so the goo still has a ways to go before it's an ideal food
source.
The
tests relied on substitute liquid and solid waste instead of actual human
wastes.
When
the real thing is introduced, there will also be concerns about pathogens that
could cause illnesses. That's where tweaking the pH levels or temperatures may
help.
Tests
showed that by increasing the system's temperatures to around 158 degrees F (70
degrees C), most germs were eliminated, yet the nutritious microbe Thermus
aquaticus survived.
Alternately,
they raised the alkalinity of another batch and found that bacteria
called Halomonas desiderata still managed to proliferate, while germs did
not.
The
team borrowed concepts from commercial aquarium filters that use fixed-film
filters to neutralize fish waste.
The
filters incorporate a bacteria-laden film and are adapted by researchers to
accommodate methane production. The result?
Solid
waste can be treated in a matter of hours instead of days. Plus, because the
system is self-contained, it doesn't really require much babysitting, other than,
you know, the necessary inputs.
There's
also the matter of taste.
Lisa
Steinberg, the lead author on the study, says that the bacteria could be mixed
with other materials and flavors to make it more palatable.
"It's
nearly certain that there would be plants grown in conjunction with this food
stuff, which would provide additional flavors and textures," she emails.
What
about the potential psychological issues associated with consuming a material
of dreary origins?
"Astronauts
already have to drink their own processed urine," says Steinberg. "So,
they are probably accustomed to things being done differently in space than on
Earth."
In
space, poop is often a problem. Maybe now poop will be part of the
solution.
While
the still-experimental concept may not exactly fire up astronaut's appetites,
it may eventually provide sustenance to space explorers who have limited buffet
options amongst the stars.
NOW
THAT'S INTERESTING
Astronauts on the International Space Station
already recycle some of their urine.
Poo, on the other hand, has a more spectacular
ending. It is blasted into space, caught in Earth's orbit and then burns up
"like a shooting star” on
re-entry.
Still, maybe you'll think twice the next time you're
catching snowflakes on your tongue.
Nathan Chandler, Contributing Writer
Nathan Chandler is a freelance writer and photographer based in Lincoln, Nebraska. He earned his B.A. from the University of Northern Iowa, and has researched and written about consumer tech for more than 10 years.
Nathan Chandler is a freelance writer and photographer based in Lincoln, Nebraska. He earned his B.A. from the University of Northern Iowa, and has researched and written about consumer tech for more than 10 years.
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