On sunny days,
the Roman citizens of Ostia
could be found on a long stone bench
near the Forum.
Friends and neighbors exchanged
news and gossip
while simultaneously attending
to more... urgent business.
These public latrines could sit
up to 20 Romans at a time,
draining waste in water conduits below.
Today, most cultures consider trips to the
restroom to be a more private occasion.
But even when going alone,
our shared sewage infrastructure
is one of the most pivotal inventions
in the history of humanity.
While many ancient religious texts
contain instructions
for keeping waste away
from drinking water and campsites,
waste management took a more familiar
shape as early as 3000 BCE.
Ancient Mesopotamian settlements often had
clay structures
made for squatting or sitting
in the most private room of the house.
These were connected to pipes which used
running water to move waste
into street canals and cesspits.
Water infrastructure like this flourished
in the Bronze Age,
and in some parts of the Indus Valley,
nearly every house had a toilet connected
to a citywide sewage system.
Ancient Cretan palaces even offered
a manual flushing option.
Researchers can’t say for certain
what inspired these early sewage systems,
but we do know that waste management
is essential for public health.
Untreated sewage is a breeding ground
for dangerous microorganisms,
including those that cause cholera,
dysentery, and typhoid.
It would be several millennia before
scientists fully understood
the relationship between
sewage and sickness.
But the noxious odors of sewage have
recorded associations with disease
as early as 100 BCE.
And by 100 AD, more complex
sanitation solutions were emerging.
The Roman Empire had continuously
flowing aqueducts
dedicated to carrying waste
outside city walls.
Chinese dynasties of the same period
also had private and public toilets,
except their waste
was immediately recycled.
Most household toilets fed into pig sties,
and specialized excrement collectors
gathered waste from public latrines
to sell as fertilizer.
In China, this tradition of waste
management continued for centuries,
but in Europe the fall of the Roman Empire
brought public sanitation
into the Dark Ages.
Pit latrines called “gongs”
became commonplace,
and chamber pots were frequently
dumped into the street.
Castles ejected waste from tall windows
into communal cesspits.
At night, so-called gong farmers
would load up the waste
before traveling beyond city limits
to dump their cargo.
Europe's unsanitary approach
persisted for centuries,
but toilets themselves underwent
some major changes.
By the late Middle Ages,
most wealthy families had commode stools—
wooden boxes with seats and lids.
And in the royal court of England,
the commodes were controlled
by the Groom of the Stool.
In addition to monitoring
the king’s intestinal health,
the Groom’s... intimate relationship
with the monarch
made him a surprisingly
influential figure.
The next major leap in toilet technology
came in 1596,
when Sir John Harrington designed
the first modern flush toilet
for Queen Elizabeth.
Its use of levers to release water
and a valve to drain the bowl
still inform modern designs.
But Harrington’s invention
stank of sewage.
Thankfully, in 1775,
Scottish inventor Alexander Cumming
added a bend in the drainpipe
to retain water and limit odors.
This so-called S-trap was later improved
into the modern U-bend by Thomas Crapper—
though the term “crap” predates
the inventor by several centuries.
By the turn of the 19th century,
many cities had developed
modern sewage infrastructure
and wastewater treatment plants,
and today, toilets have a wide range
of features,
from the luxurious to the sustainable.
But roughly 2 billion people still don’t
have their own toilets at home.
And another 2.2 billion
don’t have facilities
that properly manage their waste,
putting these communities
at risk of numerous diseases.
To solve this problem, we’ll need
to invent new sanitation technologies
and address the behavioral, financial,
and political issues
that produce inequity
throughout the sanitation pipeline.