Why the Toilet Needs an Upgrade

[Narrator] This is the toilet.

This is also a toilet. So is this.

And this is the crumbling infrastructure underneath.

In the US and other places,

the wastewater infrastructure is aging

and it's not very well suited

for dealing with a lot of the challenges in the future.

[Narrator] This is Chelsea Wald.

She spent over eight years researching the toilet

and discovered it needs a big upgrade.

[toilet flushes]

[Chelsea] Why hasn't the toilet really changed?

One of the reasons is technological lock-in.

Our predecessors spent lots of money putting these pipes

in the ground and then we're also

kind of psychologically locked into it.

It's hard for us to imagine something different.

[Narrator] Technologists are redesigning the toilet

to do more than what we asked of it before.

Previous societies knew that pee and poo

were valuable resources in terms of the nutrients in them.

The current sewage system makes it difficult

to recover that but it would be a lot easier

if we could do it at the toilet level,

rather than waiting for all the mixing to happen

and then trying to get it all out at the end.

One thing that I've seen here in the Netherlands,

piloting of vacuum toilets, these use very little water

and they suck out the waste and keep it separate

from other household wastewater,

the gray water coming out of the house

and that makes it possible to make better use of that waste.

Another innovation that I've seen

that's promising is urine diversion toilets.

So toilets that actually separate pee and poo.

These have been very hard to develop, to design

because they are awkward to use.

There is a new design called the urine trap

that does this separation a little more seamlessly

with less trouble to the user.

So the high tech toilet of the future might be a toilet

that has medical capabilities.

I talked to one innovator who has made a toilet

that actually images your poo.

And from that can determine some things about your health

and especially over time and to alert you

if there might be a problem.

The first big comprehensive sewer system

for removing human waste from a city was in London,

in the 19th century.

But some of those original sewers around the world

from the 19th, early 20th century

are still in the ground and still operating.

One big problem from some of those old sewers,

it's they were combined sewers.

So they combined stormwater with all this household water.

When there's a storm, even if it rains a little bit

in some places, the sewers overflow.

There's a couple of ways that cities are dealing with this.

It's a very, very difficult problem.

Some are digging big tunnels.

It's very expensive, massive storage underground.

Some are building green infrastructure above ground

to absorb a lot of that stormwater

so it doesn't even go into the sewer.

And then some cities are making their sewers smarter.

South Bend, Indiana have a combined sewer

that they've started putting these, you know,

movable devices, remote devices into their sewers.

And they've been able to reduce the number of overflows

a lot without actually having to dig any extra tunnels.

[Narrator] While some cities are making sewers smarter

other cities are reimagining the sewer as an energy source.

In Vancouver, a sustainable energy system was used

to heat the city's Olympic village.

[Chelsea] You can also start to harvest stuff from sewers.

Kind of works like the reverse of a refrigerator,

uses a fluid to capture the heat and then that heat

can then be transferred into a distribution system

to run through the building,

just like any other heating system.

From the perspective of someone in the building,

they would never know that the source

of the heat was sewage.

Many cities already have a big mix

of sanitation technologies.

That diversity can actually make cities

more resilient in a way.

So if you can say, as a city grows,

instead of expanding the sewer system,

it might make sense instead to introduce

building scale systems or district scale systems

or if there are areas where it really makes sense

to have onsite sanitation, because it's kind of more rural,

you could introduce systems there that make sense,

you know, ecologically for that area.

[Narrator] Wastewater treatment plants take everything

we dumped down the drain and toilet, filters it

and uses microorganisms to clean the water.

One of the problems that wastewater treatment plants face

is the residual sludge that comes out of this process.

But there's people who are now looking for new ways

to make use of this sludge.

One is to take that sludge and turn it

into a kind of biocrude that can then be used

as a transportation fuel.

In a lot of places, people have been inadvertently

drinking recycled re-used wastewater for a long time.

So these programs are called

indirect potable reuse programs.

Orange county was the pioneer of this program.

They actually clean their water to drinking water standards

using advanced technology

and then they inject it into an aquifer.

And then on the other hand, you have direct potable reuse,

and that would mean taking the cleaned up effluent

and putting it back into the pipeline

directly as drinking water.

There is a fear of the yuck factor or the ick factor,

which has held back these programs in the past.

There is a big trend for pilot projects,

for direct potable reuse all over the world

but especially in the United States.

Even in the last year or two,

it's just going to be one of the most reliable sources

of water that's available.

And you'd rather have direct potable reuse water

than no water coming from your tap, that's for sure.

So in writing this book, I came across just a wide variety

of people working on all different aspects of the toilet

from the design of public toilets

to the design of the toilet bowl

to improving sewer systems to improving pit latrines

to improving wastewater treatment

to using the products of wastewater treatment.

The toilet is really one of the most fundamental

technologies that underpin human society.

And if you want to think about it poetically,

we are connected to each other as humans

and to the planet through the toilet.

So it is so important that our toilets are good,

that they're healthy, that they're sustainable

and that everybody has access to one.