Vacuum sewer

A vacuum sewer or pneumatic sewer system is a method of transporting sewage from its source to a sewage treatment plant. It maintains a partial vacuum, with an air pressure below atmospheric pressure inside the pipe network and vacuum station collection vessel. Valves open and reseal automatically when the system is used, so differential pressure can be maintained without expending much energy pumping. A single central vacuum station can collect the wastewater of several thousand individual homes, depending on terrain and the local situation.^[1]^{[better source needed]}

Vacuum sewers were first installed in Europe in 1882. Dutch engineer Charles Liernur first applied negative pressure drainage to sewers in the second half of the 19th century.^[2]^{[non-primary source needed]} Technical implementations of vacuum sewerage systems began in 1959 in Sweden.^{[citation needed]}

Historically, vacuum sewers have been a niche product, used only in trains, airplanes, and flat areas with sandy soils and high ground water tables. Gravity sewers were used for most applications, because although vacuum sewers were cheaper to install, they were more expensive to maintain. In the 20th century, vacuum sewer technology has improved significantly: fault-locating sensors have reduced operation and maintenance costs, and some operators now consider that vacuum sewers can be cheaper to run than conventional gravity sewers.^[3]

^ Cite error: The named reference palm was invoked but never defined (see the help page).
^ Liernur, C.T., "Pneumatic Sewerage system" (PDF), sewerhistory.org
^ See (Gibbs 2016): "'When we did the pilot project study in 1993, we calculated that the present value estimate comparison for vacuum sewers and gravity sewers would intersect in 20 years,' he notes. 'At that point, we predicted that vacuum sewers would be more expensive due to maintenance and upkeep. This was based largely on data known at that time. It has been 23 years now, and we’re still not close to seeing the O&M costs that were originally estimated,' Beach continues. 'We have not crossed the present worth value line, and it will likely be another 10 years before these lines intersect.'"

[palm-1] Cite error: The named reference palm was invoked but never defined (see the help page).

[2] Liernur, C.T., "Pneumatic Sewerage system" (PDF), sewerhistory.org

[3] See (Gibbs 2016): "'When we did the pilot project study in 1993, we calculated that the present value estimate comparison for vacuum sewers and gravity sewers would intersect in 20 years,' he notes. 'At that point, we predicted that vacuum sewers would be more expensive due to maintenance and upkeep. This was based largely on data known at that time. It has been 23 years now, and we’re still not close to seeing the O&M costs that were originally estimated,' Beach continues. 'We have not crossed the present worth value line, and it will likely be another 10 years before these lines intersect.'"

[1]

[2]

[3]