Page 375 - Fair, Geyer, and Okun's Water and wastewater engineering : water supply and wastewater removal

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Introduction to Wastewater Systems 335

Figure 10.2 Sewers in Paris (Courtesy Wikepedia)
http://en.wikipedia.org/wiki/Image:Paris-Egouts-p1010721.jpg

of storm drains. The sewerage systems of London, Paris (Figs. 10.2 and 10.3), New York,
and Boston provide examples of this evolution.
The converging conduits of wastewater collection works remove wastewaters from
households and industries or stormwater in free flow as if it were traveling along branch or
tributary streams into the trunk or main channel of an underground river system.
Sometimes the main collector of combined systems had, in fact, been a brook at some
point that was eventually covered over when pollution made its waters too unsightly, mal-
odorous, and otherwise objectionable. For free or gravity flow, sewers and drains must

Figure 10.3 Wastewater Discharge into a Stream (Courtesy Wikepedia)
http://upload.wikimedia.org/wikipedia/commons/0/03/Paris-Egouts-p1010760.jpg