- Sanitary sewer
A sanitary sewer (also called, especially in the UK, a foul sewer) is a type of underground carriage system for transporting
sewagefrom houses or industry to treatment or disposal. In some areas, sanitary sewers are separate sewersystems specifically for the carrying of domestic and industrial wastewater, and are operated separately and independently of storm drains, which carry the runoff of rain and other water which wash into city streets.
In the twenty-first century developed world, sewers are usually pipelines that begin with connecting pipes from buildings to one or more levels of larger underground horizontal mains, which terminate at
sewage treatmentfacilities. Vertical pipes, called manholes, connect the mains to the surface. Sewers are generally gravity powered, though pumps may be used if necessary. The most commonly used sanitary pipe is SDR-35, with smaller sized laterals interconnected within a larger sized main.
The earliest covered sewers uncovered by archaeologists are in the regularly planned cities of the
Indus Valley Civilization. In ancient Rome, the Cloaca Maxima, considered a marvel of engineering, disgorged into the Tiber. In medieval European cities, small natural waterways used for carrying off wastewater were eventually covered over and functioned as sewers. London's River Fleetis such a system. Open drains along the center of some streets were known as ' kennels' (= canals, channels). The nineteenth century brick-vaulted sewer system of Parisoffers tours for tourists.
Simplified sanitary sewers consist of small-diameter pipes (typically 100 mm or about 4 inches), often laid at fairly flat gradients (1 in 200). The investment cost for sanitary sewers can be about half the costs of conventional sewers. However, the requirements for operation and maintenance are usually higher. Simplified sewers are most common in
Braziland are also used in a number of other developing countries.
ewers in popular culture
The image of the sewer recurs in European culture as they were often used as hiding places or routes of escape by the scorned or the hunted, including partisans and resistance fighters in WWII. The only survivors from the
Warsaw Uprisingand Warsaw Ghettomade their final escape through city sewers. Some have commented that the engravings of imaginary prisons by Piranesiwere inspired by the Cloaca Maxima, one of the world's earliest sewers.
ewers in fiction
The theme of traveling through, hiding, or even residing in sewers is a common
clichéin media, where unsanitary conditions or the strong smell of sewage are seldom mentioned. Famous examples of sewer dwelling or scenes are Teenage Mutant Ninja Turtles, Stephen King's "It", " The Third Man", "Mimic", " The Phantom of the Opera", and " Jet Set Radio Future"
urban legend, the sewer alligator, is that of giant alligators or crocodiles residing in sewers, especially of major metropolitan areas. Two public sculptures in New York depict an alligator dragging a hapless victim into a manhole. [ [http://www.npr.org/templates/story/story.php?storyId=4111768 Subway Art: New York's Underground Treasures : NPR ] ]
Alligators have been known to get into combined storm sewers in the Southeastern United States. Closed-circuit television by a sewer repair company captured an alligator in a combined storm sewer on tape. [ [http://youtube.com/watch?v=Mzh1lhV_RXE YouTube - Bad sewer pipes across America ] ]
Sanitary sewer overflow(SSO)
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