Drinking water supply and sanitation in the
United States From Wikipedia, the free encyclopedia
In the 19th century numerous American cities were afflicted with major outbreaks of disease, including cholera in 1832, 1849 and 1866 and typhoid in 1848. The fast-growing cities did not have sewers and relied on contaminated wells within the city confines for drinking water supply. In the mid-19th century many cities built centralized water supply systems. However, initially these systems provided raw river water without any treatment. Only after John Snow established the link between contaminated water and disease in 1854 and after authorities became gradually convinced of that link, water treatment plants were added and public health improved. Sewers were built since the 1850s, initially based on the erroneous belief that bad air (miasma theory) caused cholera and typhoid. It took until the 1890s for the now universally accepted germ theory of disease to prevail.
Piped water supply until 1948
However, most wastewater was
still discharged without any treatment, because wastewater was not believed to
be harmful to receiving waters due to the natural dilution and self-purifying
capacity of rivers, lakes and the sea.
Wastewater treatment only became widespread after the introduction of
federal funding in 1948 and especially after an increase in environmental
consciousness and the upscaling of financing in the 1970s. For decades federal
funding for water supply and sanitation
was provided through grants to local governments. After 1987 the system was
changed to loans through
revolving funds.
In the 1840s and 1850s the largest
cities in the U.S. built pipelines to supply drinking water from rivers or
lakes. However, the drinking water was initially not treated, since the link
between waterborne pathogens and diseases was not yet well known. In 1842 New
York City was one of the first cities in the U.S. to tap water resources
outside the city limits. It dammed the Croton River in
Westchester County, New York, and built an aqueduct from the reservoir to the
city. Also in 1842, construction was completed on Chicago's
first water works, with water mains made of cedar and a water intake located
about 150 feet (46 m) into Lake Michigan. In
1848, Boston began
construction of a water transmission system. A tributary of the Sudbury River was
impounded creating Lake Cochituate,
from where the Cochituate Aqueduct transported water to
the Brookline Reservoir that fed the city's distribution
system. In 1853 Washington, D.C. followed
suit by beginning the construction of the Washington Aqueduct to provide water from the Great
Falls on the Potomac River.
In 1854, the British physician John Snow
found that cholera was spread through contaminated water. As a result of his
findings, several cities began to treat all water with sand filters and
chlorine before distributing it to the public. Cities also began to construct
sewers. As a result of water treatment and sanitation, the incidence of
cholera and typhoid rapidly decreased. Slow sand filtration was initially the technology of
choice for water treatment, later being gradually displaced by rapid sand filtration.
In the arid American Southwest, the
water demand of rapidly growing cities such as Los Angeles exceeded local water
availability, requiring the construction of large pipelines to bring in water
from far-away sources. The most spectacular example is the first Los Angeles Aqueduct built between 1905 and 1913 to
supply water from the Owens Valley over
a distance of 375 km.
Most of the first sewer systems in the
United States were built as combined sewers (carrying
both storm water and sewerage). They discharged into rivers, lakes and the sea
without any treatment. The main reason for choosing combined sewers over
separate systems (separating sanitary sewers from storm water drains) was a belief that combined sewer systems were cheaper to
build than separate systems. Also, there was no European precedent for
successful separate sewer systems at the time. The first large-scale sewer
systems in the United States were constructed in Chicago and Brooklyn in the
late 1850s, followed by other major U.S. cities.
Few sewage treatment facilities
were constructed in the late 19th century to treat combined wastewater because
of the associated difficulties. There were only 27 U.S. cities with wastewater
treatment works by 1892, most of them "treating" wastewater through land
application. Of these 27 cities, 26 had separate sanitary and storm water sewer
systems, thus facilitating wastewater treatment, because there was no need for
large capacities to accommodate wet weather flows. Furthermore, there was a
belief that the diluted combined wastewater was not harmful to receiving
waters, due to the natural dilution and self-purifying capacity of rivers,
lakes and the sea. In the early 20th century a debate evolved between
those who thought it was in the best interest of public health to construct
wastewater treatment facilities and those who believed building them was
unnecessary. Nevertheless, many cities began to opt for separate sewer systems,
creating favorable conditions for adding wastewater treatment plants in the
future.
Where wastewater was being treated it
was typically discharged into rivers or lakes. However, in 1932, the
first reclaimed water facility in the U.S. was built
in Golden Gate Park, San Francisco, for the reuse of
treated wastewater in landscape irrigation.
Sanitary sewers were not the only
sanitation solution applied. They were particularly useful in high-density
urban areas. However, in some newly built lower-density areas, decentralized septic systems were built. They were attractive
because they reduced capital expenditures and had fewer operation and
maintenance costs compared to wastewater treatment plants.
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