This post is primarily about Design and Analysis of Waste Water Transport / Collection Systems and Drinking water transport - it may incidentally contain some information or links to waste water treatment but treatment is not the subject that interests me now. Look specifically for "Sanitary sewer" and "Sewage collection and disposal".
- http://saiindia.gov.in/english/home/public_folder/professional_practices_group/state_local_manual/PUDUCHERRY_MANUAL/Wad%20Manual/Sewerage.pdf Quotes from this link:
- People density calculated to 311 persons / Hectare (depends on FSI and area available for residential development taken to be 56% of total area)
- Total sewage water is approximately 80% of per capita water consumption subject to a minimum of 100 LPD per person (LPD = liters per day). In case where river water is used (typically in industries), the same would cause additional sewage that is in excess of per capita water consumption. How is this to be estimated?
- The peak flow (max surge) may be taken to be twice the average flow in cities. The ratio may be higher for areas with smaller population. The minimum flow may be a 1/2 to 1/3rd of the average flow.
- Provision to be made for storm water - it is generally better to have storm water to be handled separately from sewage water. Storm sewers address this. Sewer scenes in the movies The Fugitive, "Die Hard" (where Bruce Willis open a manhole to get into the subway station) and another Die Hard (probably are storm water sewers since the hero could walk into it and in it.
- "A properly functioning sewer has to carry the peak flow for which it is designed and transport suspended solids in such a manner that deposits in a sewer are kept to a minimum."
- "It is desirable to design sewers for higher velocity wherever possible... Velocity is little influenced by pipe diameter...
- The minimum diameter of public sewer may be 150 mm. In hilly areas, where extreme slope are prevalent, the size of sewer may be 100 mm."
- Maximum permissible velocity will vary from 1.4 to 3.0 m/sec depending on the type of pipe. The pipe has to be laid a min of 1m below the surface in order to protect it from external damage.
- "A manhole is an opening constructed in the alignment of a sewer for facilitating a person to access the sewer for the purpose of inspection, testing, cleaning and removal of obstruction of the sewer line. Spacing: Manhole should be built at every change of alignment, gradient or diameter at the head of all sewers and branches and at every junction of two or more sewers. A spacing allowance of 100 m per 1 m dia of sewer is a general rule in case of very large sewer...
- The width / diameter of the manhole should not be less than the internal diameter of the sewer plus 150 mm benching on both sides (150 mm + 150 mm)."
- "Use of MS pipes should be avoided since MS pipes are very much prone to chemical and septic corrosion..."
- https://en.wikipedia.org/wiki/Sanitary_sewer (this is the interesting part)
- "A sanitary sewer (also called a foul sewer and a covered sewer) is an underground carriage system specifically for transporting sewage from houses and commercial buildings through pipes to treatment or disposal. Sanitary sewers serving industrial areas also carry industrial wastewater. The system of sewers is called sewerage. Sanitary sewers are distinguished from open sewers in that the sanitary system is closed off from its surroundings to limit interaction between the waste and the landscape that it travels through. They are also usually distinguished from combined sewers, which handle not only sewage but also surface runoff. Open sewers, consisting of gutters and urban streambeds, were common worldwide before the 20th century. In most of the developed countries, large efforts were made during the late 19th and early 20th centuries to cover the formerly open sewers, converting them to closed systems with cast iron, steel, or concrete pipes, masonry, and concrete arches. Open sewers are not used in developed countries today, but they remain in use in many developing countries."
- "For decades, when sanitary sewer pipes cracked or experienced other damage, the only option was an expensive excavation, removal and replacement of the damaged pipe, typically requiring street repavement afterwards. In the mid-1950s a unit was invented where two units at each end with a special cement mixture in between was pulled from one manhole cover to the next, coating the pipe with the cement under high pressure which then dried at a fast rate, sealing all cracks and breaks in the pipe."
- https://en.wikipedia.org/wiki/Sewage_collection_and_disposal
- "Separate sanitary sewer systems are designed to transport sewage alone. In communities served by separate sanitary sewers, another pipe system is constructed to convey stormwater runoff directly to surface waters. Most municipal sewer systems constructed today are separate sewer systems."
- The most important thing: "During the early 19th century, the River Thames was effectively an open sewer, leading to frequent outbreaks of cholera epidemics. Proposals to modernise the sewerage system had been made during 1856, but were neglected due to lack of funds. However, after the Great Stink of 1858, Parliament realised the urgency of the problem and resolved to create a modern sewerage system. The civil engineer Joseph Bazalgette, constructed a modern sewerage system for London in the mid-19th century. Joseph Bazalgette, a civil engineer and Chief Engineer of the Metropolitan Board of Works, was given responsibility for the work. He designed an extensive underground sewerage system that diverted waste to the Thames Estuary, downstream of the main centre of population. Six main interceptor sewers, totalling almost 100 miles (160 km) in length, were constructed, some incorporating stretches of London's 'lost' rivers. Three of these sewers were north of the river, the southernmost, low-level one being incorporated in the Thames Embankment. The Embankment also allowed new roads, new public gardens, and the Circle Line of the London Underground. The intercepting sewers, constructed between 1859 and 1865, were fed by 450 miles (720 km) of main sewers that, in turn, conveyed the contents of some 13,000 miles (21,000 km) of smaller local sewers. Construction of the interceptor system required 318 million bricks, 2.7 million cubic metres of excavated earth and 670,000 cubic metres of concrete. Gravity allowed the sewage to flow eastwards, but in places such as Chelsea, Deptford and Abbey Mills, pumping stations were built to raise the water and provide sufficient flow. Sewers north of the Thames feed into the Northern Outfall Sewer, which fed into a major treatment works at Beckton. South of the river, the Southern Outfall Sewer extended to a similar facility at Crossness. With only minor modifications, Bazalgette's engineering achievement remains the basis for sewerage design up into the present day."
- https://en.wikipedia.org/wiki/Joseph_Bazalgette
- "Bazalgette's foresight may be seen in the diameter of the sewers. When planning the network he took the densest population, gave every person the most generous allowance of sewage production and came up with a diameter of pipe needed. He then said 'Well, we're only going to do this once and there's always the unforeseen' and doubled the diameter to be used. His foresight allowed for the unforeseen increase in population density with the introduction of the tower block; with the original, smaller pipe diameter the sewer would have overflowed in the 1960s, rather than coping until the present day as it has."
- https://www.waternz.org.nz/Folder?Action=View%20File&Folder_id=135&File=c_meadowcroft_et_al.pdf: Nice paper on evaluation of waste water systems - which is very close to the area this post is interested in.
- http://web.mit.edu/watsan/Docs/Student%20Theses/Brazil/Choi2003.pdf: provides an interesting design of waste water system - though from an academic view.
- Black water contains water from toilets while grey water excludes water from toilets. Keywords: Cesspit, Chamber Pot
- https://en.wikipedia.org/wiki/Sewage_treatment
- "For most cities, the sewer system will also carry a proportion of industrial effluent to the sewage treatment plant which has usually received pretreatment at the factories themselves to reduce the pollutant load. If the sewer system is a combined sewer then it will also carry urban runoff (stormwater) to the sewage treatment plant."
- "Sewerage systems capable of handling storm water are known as combined sewer systems. This design was common when urban sewerage systems were first developed, in the late 19th and early 20th centuries.Combined sewers require much larger and more expensive treatment facilities than sanitary sewers. Heavy volumes of storm runoff may overwhelm the sewage treatment system, causing a spill or overflow. Sanitary sewers are typically much smaller than combined sewers, and they are not designed to transport stormwater...Communities that have urbanized in the mid-20th century or later generally have built separate systems for sewage (sanitary sewers) and stormwater, because precipitation causes widely varying flows, reducing sewage treatment plant efficiency...As rainfall travels over roofs and the ground, it may pick up various contaminants including soil particles and other sediment, heavy metals, organic compounds, animal waste, and oil and grease. Some jurisdictions require stormwater to receive some level of treatment before being discharged directly into waterways."
Flush toilet:
Additional reading:
