Time of Waste - The Ripple Effect: The Fate of Freshwater in the Twenty-First Century - page 89

five square blocks, while hundreds more—entire families, often—were infected by the
mysterious disease. Known as cholera, the illness had been feared in Britain since dev-
astating outbreaks in the 1830s and 1840s, one of which killed almost seventy-five hun-
dred Londoners within two years. But no one knew how cholera was transmitted. Most
experts suspected it was airborne, passing from one person to another by coughing or
breathing.
John Snow, a private doctor, had a novel theory: he believed that cholera was trans-
mitted by contaminated drinking water. He studied water samples under a microscope
and plotted the patterns of cholera death on a map. His “Ghost Map” showed the disease
radiating from an epicenter at the Broad Street pump, which drew from a well beneath
Golden Square. Authorities shut down the pump, and within days the cholera epidemic
disappeared.
In pinpointing the locus of the outbreak, Snow had pioneered the science of epidemi-
ology. An assistant curate later discovered that the outbreak had been triggered when a
sick baby's diapers were thrown down the well, infecting the water. Shortly after Snow
created his Ghost Map, an Italian researcher named Filippo Pacini identified the chol-
era bacteria itself, Vibriocholerae,which circulates from one person's feces to another
person's stomach, and back again. Although he published his findings, Pacini's work was
ignored until 1884.
From that point on, the elimination of human and animal waste from water supplies
was one of the central goals of water treatment around the world, and one of the most
important efforts in the history of public health. Yet today, much of our freshwater is
mixed with treated sewage; some of it is used for irrigation, and some of it we drink.
THE WATER FACTORY
A deeply embedded human trait is to be revolted by the idea of drinking sewage, and
there are sound reasons for this. As John Snow discovered nearly two centuries ago,
wastewater contains many contaminants that can lead to serious illness. But domest-
ic sewage includes runoff from sinks, washing machines, and lawns; only 10 percent of
household waste-water comes from the toilet, and most of that does not include solids.
In other words, household effluent is about 99 percent water, which can safely and eco-
nomically be recycled.
Although many people are not aware of this, water systems across the country take
drinking water from rivers or lakes, then discharge treated wastewater back into those
same water bodies; the water flows downstream, and at the next community the cycle