[♪ INTRO] Look. We all poop, but pretty much nobody wants
to deal with it. We don't want to touch it, smell it, look
at it... And there’s a really good reason for that. While your own poop probably won't hurt you,
many serious diseases, like cholera, typhoid, and polio, are all caused by microbes in human
waste. Thankfully, most of us are relatively protected
from them and enjoy convenient, clean pooping experiences -- but it’s only because of
the unsung heroes of your bathroom. You probably don’t think about them much,
but these little pieces of technology are hard at work every day, protecting you from
your own waste -- and everyone else’s. Here are six of them. It may not get lots of fame and glory, but
the flush toilet is a kind of modern masterpiece. Think about it: There’s no more, like, walking
out into the cold outhouse in the dark, no stinky chamber pots tucked under the bed. You can poop in the comfort of your own home,
and it’s magically whisked away down a pipe and into the sewer or the septic tank. The toilet may be one of the greatest inventions
ever, and much of its success is thanks to a little-known hero: the S-bend. If it hadn’t been created, your bathroom
-- and probably the rest of your house -- would be filled with… like, just some nasty sewage
stink. The S-bend was patented in 1775 by Alexander
Cumming, who was also the first to patent a flush toilet design. Despite the common misconception, it was not
Thomas Crapper -- as great as that would be. Today, your toilet probably has a differently
shaped pipe, called a U-bend, since it’s less likely to jam up. But the technology works the same way. Water settles into the bend in the pipe, also
known as the trap, and it blocks stinky sewage gases from moving up the pipe and out of your
toilet. When you flush, a large volume of water rushes
from the cistern, or tank, into the toilet bowl. It pushes the water in the trap up and over
the bend, ultimately creating a siphon that sucks the waste out of your toilet and down
the pipe. Then, the water in the bowl and trap is gradually
replaced as the cistern refills. And all those smelly gases are kept exactly
where they belong: not in your house. Even if the ingenious bend in your pipes prevents
sewer gases from wafting into your home, you probably create some stink all by yourself. Nobody’s poop smells like roses, but when
your roommate walks into the bathroom right after you were in there, you may kind of wish
it did. That’s where corporate America came in. Science and entrepreneurs teamed up to create
toilet spray, a solution for your stink. Just spray it into the bowl before you go,
and your problems are supposedly solved. This spray works by creating a little oil
slick on the surface of the water in your toilet bowl. This oil acts as a barrier between the toilet
water and the air, trapping smelly molecules so they don’t stink up the bathroom. There are several commercial brands -- like
Poo-purri, V.I. Poo, and Just a Drop -- as well as homemade
versions. But they all contain basically the same main
ingredients: essential oils, alcohol, and glycerine or soap. The essential oils create the barrier and
provide the pleasant odor. And the glycerin or soap, as well as the alcohol,
act as surfactants and help the oily and watery ingredients mix. Officially, the watery and oily molecules
are called hydrophilic and hydrophobic, respectively. And they don’t like to mingle. Surfactants can make them mix because those
molecules have both hydrophilic and hydrophobic parts. They essentially hold hands with the oil and
the water, allowing things to blend and keeping everything from separating in the spray bottle. There’s no shame in your number two, but
your roommate might thank for you for applying one of these scented spritzes before you… go make your deposit. No matter whether you live by yourself or
with a bunch of roommates, you should probably still be using another simple, important feature
of your toilet: the lid. It’s not just there to prevent things from
falling in or for aesthetic reasons: It serves an important sanitary purpose. Putting the lid down before you flush prevents
the dreaded toilet plume! It’s a real thing! Ah—toilet plumes, they occur during flushing. When water rushes into the toilet bowl, tiny
droplets of liquid, which contain microbes from your waste, are blown out and start floating
around the air. Which nobody wants. Get ready to, you know, clutch your pearls
here: one study found that the bacterium Clostridium difficile, which can cause diarrhea and severe
colon inflammation, was suspended in air up to 90 minutes after flushing! And other studies have shown that norovirus
-- a highly contagious cause of vomiting, diarrhea, and general misery -- can also end
up floating around there and eventually settling on surfaces in your bathroom… like your
toothbrush. So, for the sake of humanity, put a lid on
it! Of course, if you’re using a public toilet,
these don’t usually have lids. According to at least one toilet maker, that’s
because people don’t want to touch them, and it’s one more part to clean. They also would block those fancy auto-flush
sensors. Still, the seat is probably the least of your
worries. Public toilets are frequently cleaned -- at
least, hopefully -- and the skin on your butt is a pretty good barrier to microbes. So you’ll probably be fine. The bigger risk is getting microbes on your
hands. So handling those fancy toilet seat covers,
or fashioning your own out of toilet paper, is probably not a great idea, since these
paper supplies are prime targets for the toilet plume. Instead, some experts just recommend washing
your hands thoroughly on the way out. And I will look at you… if you don’t. Like this. Now, you can take all kinds of precautions
in your home to avoid your waste. But what about when you’re in public and
there isn’t a bathroom around? Enter the chemical toilet -- also known as
the porta-potty. The porta-potty is nobody's favorite, but
without them, outdoor festivals, construction sites, and large road races would get pretty
messy pretty fast. These toilets are basically just big plastic
closets full of poo, but they’re still designed so that you can think about your waste as
little as possible. That’s primarily thanks to that mysterious
blue stuff in the tank. Among other things, this liquid contains a
biocide -- something like gluteraldehyde or helpful, non-smelly bacteria -- to kill the
microbes in poop that create stink. Other porta-potties used to use formaldehyde
for this, but formaldehyde is actually pretty toxic if you come into contact with it, like
in the event of a dreaded splash back. Today’s blue stuff also contains fragrance
to mask odors -- because there will be odors -- and a surfactant to make everything mix
together. But why is that stuff always blue? Well, it’s mostly for aesthetics. It helps hides the waste in the tank so you’re
not treated to an up close and personal view of other people’s poop. It also serves a crude indicator of when the
tank needs to be emptied. When there is too much waste in there, the
blue fluid turns green. So how do they make that happen? Well, it’s not fancy chemical reactions. There’s also yellow stuff going in there,
and yellow and blue make green. It’s just… just art class y’all. So if you see the liquid in the porta-potty
tank is green, you probably should use a different one if there’s one available. But your nose also will probably have told
you that. Thankfully, airplanes do not have water-filled
flush toilets. If they did, turbulence would get nasty real
fast. For a while, though, we didn’t actually
have a good alternative. In the early days of flying, planes had a
slop bucket, and World War II pilots often had to pee in bottles. I don’t know about you, but these both sound
like a nightmare on a commercial flight. Until the mid-1980s, most airliners used what
was essentially a porta-potty with a pump-powered flushing mechanism. And it pushed the blue fluid into the bowl
and then flushed the waste down into a holding tank. But this system had some major drawbacks. First, to accommodate all that flushing, planes
had to carry hundreds of gallons of the blue solution, which adds a lot of weight and reduces
fuel efficiency. Second, these systems had a habit of leaking. And if you ever heard of the dreaded blue
ice falling from the sky, this is where that came from. If the waste managed to leak onto the exterior
of the plane, it would freeze, because at 9000 meters the air temperature is around
-50°C. Then, as the plane started to descend towards
the airport, this blue poo-sicle would begin to melt and detach from the plane -- which
is not only gross but actually dangerous. Even a relatively small chunk falling from
a height generates a lot of force. Blue ice falling off of descending airplanes
is known to have torn through the roof of a house and smashed a car. This isn’t a made-up thing! It actually happened. And then you have to call your insurance company
and be like, “I don’t know man, it’s just a chunk of blue stuff and poop. It’s on my car. I don’t—I don’t—I don’t know how
to explain it!” Thankfully, most planes nowadays use a fluid
free system called a vacuum toilet. Now, when you flush the toilet on a plane,
a pump generates suction to pull the waste into the holding tank. A special non-stick coating on the toilet
bowl also makes sure there’s a relatively clean exit, all without the need for a lot
of fluid. While it may make a terrifying sound, the
vacuum toilet has made planes much more fuel efficient. And it’s made living near an airport a lot
less terrifying. Now once you flush, you probably don’t think
much about your poop. But even if it’s no longer a problem for
you personally, collectively, it’s a big problem. We humans create large volumes of waste, and
for the sake of public health -- and our noses -- it needs to be processed before it goes
back into the world. We’ve talked sewage treatment on SciShow
before, but the real heroes in this process are the microbes. After the garbage and some other solids are
filtered out of sewage, microorganisms are put to work breaking down the leftover organic
matter. In other words, they feast on your poo. Sewage treatment plants are a virtual microbe
zoo, with hundreds of different species enjoying that smorgasbord: bacteria, of course, but
also fungi, protozoans, rotifers, and nematodes. A lot of these microbes are already in your
waste when it arrives at the plant, or they could come in from the surrounding environment. Many treatment plants even seed their sludge
with a bit of microbe-filled sewage, too. They use it kind of like a sourdough bread
starter, if you’re okay with that analogy.
[DING] The treatment process provides the beneficial
microbes with ideal conditions in terms of temperature, aeration, and acidity so they
can do their job most efficiently. Then, before all that waste goes into the
environment, the microbes are killed off -- which makes sense. But someday, scientists might have another
use for them, too. See, all this waste processing requires a
lot of electricity. So some teams are trying to take advantage
of those sewage microbes and turn them into a battery. It’s called a microbial fuel cell. When cells -- including bacterial ones -- convert
food into energy, they do it using something called the electron transport chain. They essentially shuttle electrons around. The idea behind a microbial fuel cell is to
stick some bacteria in a chamber, keep stuffing them with sewage, and collect the ions and
electrons that spill out. Then, as those charged particles flow through
a wire, they create an electric current that can be stored in a battery. This technology is still being developed,
and it remains to be seen if it can work on the huge scale of a municipal sewage treatment
plant, but that’s still pretty slick. Using technology to protect you from your
waste is an easy place to start a joke, but it’s also kind of a big deal. Lack of basic sanitation is linked to at least
280,000 deaths per year. And the United Nations reports that one of
biggest factors determining child survival worldwide is sewage disposal. The good news is, we’re making progress. But if you’re a lucky person with access
to a fancy U-bend toilet and modern sanitation, don’t take it for granted! The science that protects your from your poop
makes your life more pleasant and probably longer, too! Thanks for watching this episode of SciShow! You might spend a lot of your time and energy
avoiding your waste, but animals have found some pretty clever ways to put theirs to work. Like, we’re talkin’ poop shields. You can learn about them -- and five other
ways animals use their poop -- in our episode all about that. [♪ OUTRO]
