Joan Cartan-Hansen, Host: We're pretty lucky to have access to proper sewage or waste water treatment systems.

We haven't always had that and many people in the world still don't.

Find out more about the flow of sewage treatment through time and maybe your back yard.

[MUSIC] Student: What's going on?

Mom: Toilet's clogged.

Student: So, what I am supposed to do?

Cartan-Hansen: That's a problem humans have faced for a long time.

When there were just a few people, pooping outside wasn't a problem.

But by 3000 B.C., the Indus people had it with the stink and developed the first sanitation system.

They poured water down indoor drains to push the waste into pipes that ran into a river or into a pit dug in the ground.

There were waste systems in ancient Greece and the Romans had complex underground sewage pipes to carry waste away.

But by the middle ages, humans were back to tossing sewage into pits or even into open ditches along the street.

It smelled and spread disease.

By the way, it wasn't until the mid-1800's, that scientists proved a link between untreated sewage and illnesses like typhoid and cholera.

By 1855, the first sewage systems were built in New York and Chicago.

At first, the sewage from those systems were dumped untreated into rivers.

But by 1914, engineers Edward Arden and William Locket discovered active sludge.

a biological waste water treatment system still being used today.

Student: But what if you aren't in a city with a sewage system?

Cartan-Hansen: Approximate 20 percent of Americans use a septic tank for their waste disposal.

Waste water from sinks, baths, showers and toilets flow out of the house into a giant tank buried in the ground.

Bacteria inside the tank starts breaking down the organic matter.

The septic tank acts like a settling pond.

The heavy solids sink to the bottom.

The fats, greases and oils, called scum, floats to the top.

Filtered water flows out of the tank into pipes into a drain field.

Most septic tanks are emptied every three to five years.

Student: How do they make sure the water is safe?

Cartan-Hansen: Scientists like Anne test water to assure its purity.

Anne Epperson: People go to the bathroom, the water's collected goes in the sewers and it comes to this facility.

And we take that sample, before it comes into the plant, and we can take it and see if there's viruses or bacteria that are harmful.

Cartan-Hansen: This lab tests all sorts of different samples from lots of locations, even checking the water in the city's swimming ponds.

Epperson: If there's bacteria and if it's too high and, you know, we can tell the parks and recreation if the water is safe to swim in.

And if it isn't, and we closed it down and we take care of the problem.

Cartan-Hansen: The scientists here can even track levels of disease like SARS-COV-2, the virus that causes COVID-19.

Epperson: When you used to go to the bathroom in the fecal material, you actually, um, slough off some of the COVID if you have it.

People that, that have it and have symptoms and people that don't have it, it'll be seen in the wastewater.

And so we can actually track through a community earlier and find out how much is actually happening.

Cartan-Hansen: The tests can't identify who has the disease, but it can tell health officials if the level of the virus is increasing in the community and that allows them to take precautions to protect the population.

Student: What about parts of the world without sewage treatment.

What do they do?

Cartan-Hansen: Some use pit toilets or holes in the ground.

Some have septic tanks, but those tanks don't always work.

Basically, 67 percent of the world has no proper sewage treatment.

And in developing countries, 80 to 90 percent of waste water goes directly into streams and rivers.

And that can spread disease and damage the environment.

Student: So what can I do?

Cartan-Hansen: There're simple things you can do to keep your own sewage treatment working.

Don't put anything down the toilet except the four P's: poop, pee, puke and toilet paper.

Don't put grease down your sink.

Don't put any medications down the drain or in the toilet.

In many places, don't let anything but rain water go down storm drains.

That water usually isn't usually treated before it goes in the local stream or river.

And you can support efforts worldwide to help communities get clean water and sewage treatment.

We all live on one planet with a limited amount of water.

So let's keep it clean.

Student: Wow.

I never thought about sewage treatment.

That's really important.

But I still need to go to the bathroom so what I am supposed to do?

Student: Are you kidding me?

I think it's time for me to improve our sewage system.

I'm going in.. Cartan-Hansen: If you want to learn more about sewage, check out the Science Trek website.

You'll find it at science trek dot org.

[MUSIC] n of Science Trek on Idaho Public Television is made possible through the generous support of the Laura Moore Cunningham Foundation, committed to fulfilling the Moore and Bettis family legacy of building the great state of Idaho.

By the Idaho National Laboratory, mentoring talent and finding solutions for energy and security challenges, by The Friends of Idaho Public Television and by the Corporation for Public Broadcasting.