I am an engineering professor,
and for the past 14 years
I've been teaching crap.
(Laughter)
Not that I'm a bad teacher,
but I've been studying and teaching
about human waste
and how waste is conveyed
through these wastewater treatment plants,
and how we engineer and design
these treatment plants so that we can protect
surface water like rivers.
I've based my scientific career
on using leading-edge molecular techniques,
DNA- and RNA-based methods
to look at microbial populations in biological reactors,
and again to optimize these systems.
And over the years,
I have developed an unhealthy obsession with toilets,
and I've been known to sneak into toilets
and take my camera phone
all over the world.
But along the way, I've learned
that it's not just the technical side,
but there's also this thing called the culture of crap.
So for example,
how many of you are washers
and how many of you are wipers?
(Laughter)
If, well, I guess you know what I mean.
If you're a washer, then you use water
for anal cleansing. That's the technical term.
And if you're a wiper,
then you use toilet paper
or, in some regions of the world
where it's not available, newspaper
or rags or corncobs.
And this is not just a piece of trivia,
but it's really important to understand
and solve the sanitation problem.
And it is a big problem:
There are 2.5 billion people in the world
who don't have access to adequate sanitation.
For them, there's no modern toilet.
And there are 1.1 billion people
whose toilets are the streets
or river banks or open spaces,
and again, the technical term for that is
open defecation,
but that is really simply
shitting in the open.
And if you're living in fecal material
and it's surrounding you, you're going to get sick.
It's going to get into your drinking water,
into your food, into your immediate surroundings.
So the United Nations estimates
that every year, there are 1.5 million child deaths
because of inadequate sanitation.
That's one preventable death every 20 seconds,
171 every hour,
4,100 every day.
And so, to avoid open defecation,
municipalities and cities
build infrastructure, for example, like pit latrines,
in peri-urban and rural areas.
For example, in KwaZulu-Natal province in South Africa,
they've built tens of thousands of these pit latrines.
But there's a problem when you scale up
to tens of thousands, and the problem is,
what happens when the pits are full?
This is what happens.
People defecate around the toilet.
In schools, children defecate on the floors
and then leave a trail outside the building
and start defecating around the building,
and these pits have to be cleaned
and manually emptied.
And who does the emptying?
You've got these workers
who have to sometimes go down into the pits
and manually remove the contents.
It's a dirty and dangerous business.
As you can see, there's no protective equipment,
no protective clothing.
There's one worker down there.
I hope you can see him.
He's got a face mask on, but no shirt.
And in some countries, like India,
the lower castes are condemned
to empty the pits,
and they're further condemned by society.
So you ask yourself, how can we solve this
and why don't we just build Western-style flush toilets
for these two and a half billion?
And the answer is, it's just not possible.
In some of these areas, there's not enough water,
there's no energy,
it's going to cost tens of trillions of dollars
to lay out the sewer lines
and to build the facilities
and to operate and maintain these systems,
and if you don't build it right,
you're going to have flush toilets
that basically go straight into the river,
just like what's happening in many cities
in the developing world.
And is this really the solution?
Because essentially, what you're doing is
you're using clean water
and you're using it to flush your toilet,
convey it to a wastewater treatment plant
which then discharges to a river,
and that river, again, is a drinking water source.
So we've got to rethink sanitation,
and we've got to reinvent the sanitation infrastructure,
and I'm going to argue that to do this,
you have to employ systems thinking.
We have to look at the whole sanitation chain.
We start with a human interface,
and then we have to think about how feces
are collected and stored,
transported, treated and reused —
and not just disposal but reuse.
So let's start with the human user interface.
I say, it doesn't matter if you're a washer or a wiper,
a sitter or a squatter,
the human user interface should be clean
and easy to use, because after all,
taking a dump should be pleasurable.
(Laughter)
And when we open the possibilities
to understanding this sanitation chain,
then the back-end technology,
the collection to the reuse, should not really matter,
and then we can apply
locally adoptable and context-sensitive solutions.
So we can open ourselves to possibilities like,
for example, this urine-diverting toilet,
and there's two holes in this toilet.
There's the front and the back,
and the front collects the urine,
and the back collects the fecal material.
And so what you're doing is you're separating the urine,
which has 80 percent of the nitrogen
and 50 percent of the phosphorus,
and then that can then be treated
and precipitated to form things like struvite,
which is a high-value fertilizer,
and then the fecal material can then be disinfected
and again converted to high-value end products.
Or, for example, in some of our research,
you can reuse the water by treating it
in on-site sanitation systems
like planter boxes or constructed wetlands.
So we can open up all these possibilities
if we take away the old paradigm of flush toilets
and treatment plants.
So you might be asking, who's going to pay?
Well, I'm going to argue that governments
should fund sanitation infrastructure.
NGOs and donor organizations,
they can do their best, but it's not going to be enough.
Governments should fund sanitation
the same way they fund roads
and schools and hospitals
and other infrastructure like bridges,
because we know, and the WHO has done this study,
that for every dollar that we invest
in sanitation infrastructure,
we get something like three to 34 dollars back.
Let's go back to the problem of pit emptying.
So at North Carolina State University,
we challenged our students to come up with a simple solution,
and this is what they came up with:
a simple, modified screw auger
that can move the waste up
from the pit and into a collecting drum,
and now the pit worker
doesn't have to go down into the pit.
We tested it in South Africa, and it works.
We need to make it more robust,
and we're going to do more testing
in Malawi and South Africa this coming year.
And our idea is to make this
a professionalized pit-emptying service
so that we can create a small business out of it,
create profits and jobs,
and the hope is that,
as we are rethinking sanitation,
we are extending the life of these pits
so that we don't have to resort
to quick solutions
that don't really make sense.
I believe that access to adequate sanitation
is a basic human right.
We need to stop the practice
of lower castes and lower-status people
going down and being condemned to empty pits.
It is our moral, it is our social
and our environmental obligation.
Thank you.
(Applause)