Could Recycled Urine Make Sustainable Fertilizer?

Sports stadiums have a lot of grass that needs to be fertilized, and a lot of urine to dispose of. Learn how researchers are working to solve both problems at once in this episode of BrainStuff.

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Episode Transcript

Speaker 1 (00:02):
Welcome to brain Stuff from How Stuff Works. Hey, brain Stuff,
Lauren vocal bam here. Have you ever just tossed a
nice pair of shoes after slogging around in the mud
all day at a festival, or sent a rug or
piece of upholstered furniture to the dump because a beloved
mammal in your household, be it dog, cat, or baby,
made an impressively unfixable mess of it using only their

(00:23):
bodily fluids. We throw valuable things away all the time
because they're disgusting and we don't know what else to
do with them. But one research team at the University
of Florida is taking a hard look at how we
deal with something that's definitely valuable but also essentially gross
our p as humans were understandably reluctant to spend a

(00:44):
lot of time fiddling with our own waste products. After
all our bodies through with it. It smells bad and
it could potentially make a sick We are done there,
take it away. But just because we're not particularly keen
on hanging out with our p doesn't mean it couldn't
save the world. Old urine is full of nutrients like nitrogen, phosphorus,
and potassium, the same stuff we mine out of the

(01:06):
ground and air to make the fertilizers that we grow
our food with. We spoke with University of Florida Associate
Professor Trevor Boyer. He said the paradigm shift will be
in recognizing that wastewater has a lot of valuable products
contained within it. What we'd like to do is recover
those valuable products and put them to a beneficial use.
In most parts of the world, with municipal plumbing, urine

(01:28):
gets flushed to the wastewater treatment plant, along with everything
else that goes down the drain or toilet, biodegradable material,
assorted cleaning chemicals, and nutrients that are great for making
plants grow, but which can cause algae and rivers and
lakes to explode and choke up waterways. The wastewater treatment
plant removes as much of this negative stuff as possible
so that it doesn't pollute the environment. Boyer said, the

(01:52):
problem is wastewater is pretty useless as a coming gold stream,
but if you could separate it out, you'd be able
to recover drinking water, fertilizer, TiAl energy, and even metals
like gold and silver. The key to mining our waste
for these treasures would be in separating the waste streams
at the source. At this point, that is difficult to
do in our homes, where plumbing and appliances are set

(02:13):
to dump dish SuDS and urine down the same pipe. However,
Boyer's team realized it would be a lot easier at
a giant football stadium where nobody's doing laundry but a
lot of people are urinating, and right around the corner
from the lab there just happens to be a football
field with more than an acre of turf grass in
need of fertilization, affectionately known as the swamp. The University

(02:34):
of Florida football stadium seats nine fans during seven home
games each year. A thesis written by Boyer's student Bryce
sink Graph calculated how many times each person would use
the bathroom during one event and how much nitrogen, phosphorus,
and potassium could be harvested from that urine. They concluded
that in one football season, Gator fans would produce more

(02:55):
than enough nutrients to fertilize the field for that season.
Boyer said, at us point, nobody in the US is
capturing urine on site. And saving it in storage tanks
to use as fertilizer, and he says that the easiest
way to accomplish that would be to install special waterless
urinals in the men's bathrooms, which are already being used
in this country as water saving devices. After that, the

(03:18):
urine could be piped to storage tanks under the stadium
and held while chemistry did its magic changing the chemical
composition of the urine into a form of nitrogen usable
on grass. Although mining our waste products for valuable nutrients
may not be easy to implement overnight, Lawyer says it's
important to look at the costs and benefits of it
and how we might accomplish it. He said, the big

(03:39):
question is how do we make our society more sustainable.
The answer might hinge on our ability to change the
way that we think about our own p Today's episode
was written by Jesslyin Shields and produced by Tyler Clang.
For more on this and lots of other Golden topics,
visit our home planet, how Stuff Works dot com. M