Sewer

Slovak term: Slovenský termín

1. A pipe or conduit that carries wastewater or drainage water (WHO 2006a)
2. A channel or conduit, usually subterranean, for carrying off water and waste matter, such as surface water from rainfall, household waste from sinks and baths, and wastewater from industrial works (WHO 2006b).

Explanation

Off-site sewerage systems transport excreta through sewer pipes away from the household using water and do not involve on-site decomposition to a significant degree. Sewers are the pipes that form a sewerage system that convey sewage or wastewater. They can be made from a variety of materials such as concrete, cast iron, plastic, or especially for older sewers, brick. The sewer pipes are laid in a trench, which is filled with a granular material. This bedding and surround protects and supports the pipe, makes it easier to compact the material in the trench and, thus, avoid settlement of the ground above the pipe for easier laying in the correct position. Pipes are manufactured in short lengths to make it easier to transport and lay them. Some metal pipes are bolted together, some plastic pipes can be heated and welded to form a joint, but many cast iron and concrete pipes have a spigot and socket joint. The end of one pipe can be pushed into a socket of the next pipe. This allows for some movement and allows the pipes to be laid at a slight angle to each other so they can be laid in a gentle curve (WHO 2006b).

A sewer is usually a below ground public drain used to carry and remove human liquid waste matter away from a property to a sewage treatment facility. Where possible, a sewer is laid on grade, but pumping may be required. The size of a sewer may vary depending on needs, sometimes as small as 100mm. It is a public asset usually maintained by the sewerage authority. Storm water should be separated from sanitary sewers but in some locations storm water drains and sanitary sewers are the same (World Plumbing Council Working Group 2008).

Example

A sewer is the public piped drainage system to which the building drain, or property drains connect. It transports both sewage and waste water from the connecting building or property drains to a public sewage treatment plant for safe treatment and disposal, or reuse (World Plumbing Council Working Group 2008).

References

• WHO (2006a) Safe Use of Wastewater, Excreta and Greywater
• WHO (2006b) Health aspects of plumbing

Links

• WHO — The Health and Environment Lexicon
• WHO (1992) A guide to the development of on-site sanitation
• WHO (2004) Safe piped water: managing microbial water quality in piped distribution systems
• WHO (2003) Linking technology choice with operation and maintenance in the context of community water supply and sanitation: A reference document for planners and project staff
• WHO (2001) Water quality: Guidelines, standards and health