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😷 | Development of a model that detects the new corona from sewage such as Hokkaido University.Sensitivity 100 times.Early detection of epidemics

Photo Tohoku University, Hokkaido University, and AMED build a mathematical model to estimate the number of infected people from the new corona concentration in sewage.

Development of a model that detects the new corona from sewage such as Hokkaido University.Sensitivity 100 times.Early detection of epidemics

If you write the contents roughly
In Japan as well, many methods for detecting the gene for the new coronavirus from sewers are being implemented.

The new coronavirus binds to and infects a protein called the ACE2 receptor.Speaking of new coronavirus infections ... → Continue reading

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Wikipedia related words

If there is no explanation, there is no corresponding item on Wikipedia.

New coronavirus

New coronavirus(Shingata coronavirus,English: Novel coronavirus, nCoV) IsCoronavirus familyOrthocoronavirus subfamilyBelongs toウ イ ル スOf these, it is a tentative name given to those that are medically and publicly important.[1][2][3][4].

In particularHuman coronavirusIt is often used in. (Human) Coronavirus against humanityEndemic diseaseIs believed to becoldCauses (common cold) -like symptoms,(English edition)Is prevalent as a serious infection, often accompanied by pneumonia[1][2][3][4].

Virus type

The following viruses were positioned as new coronaviruses before their official names were given.

Types of new coronaviruses that are pathogenic to humans
Formal nameOther namesSusceptible host[† 1]First discovery location (discovery year)Infection
SARS coronavirus 2 (SARS-CoV-2)[† 2][5][6]2019-Ncov

SARS virus 2

Human coronavirus 2019 (HCoV-19)

Bat,Scale armorChugoku-Wuhan(2019)New Coronavirus Infection (2019) (COVID-19)[† 3][4][7]
MERS coronavirus (MERS-CoV)[† 4]Middle east virus

MERS virus

Camel flu virus

camel,BatSaudi Arabia-Jeddah(2012)Middle East respiratory syndrome (MERS)[8][9].
Human coronavirus HKU1 (HCoV-HKU1)New Haven Virus[Annotation 1]A mouseHong Kong (2005)Mild respiratory tract infection, rarely severe pneumonia
SARS coronavirus (SARS-CoV, SARS-CoV-1)[† 2]SARS virusChinese cabbage,BatChugoku-Foshan(2002)Severe acute respiratory syndrome (SARS)[9]
  1. ^ (English edition)May not be succeeded.
  2. ^ a b This virus is not a different speciesSARS-related coronavirusIs considered to be one of the stocks of.
  3. ^ Synonyms include 2019 coronavirus pneumonia,Wuhan pneumoniaThere is a syndrome.
  4. ^ (English edition),(English edition)Including stocks of.

All of the above four viruses belong to the genus Betacoronavirus (betacoronavirus) Belongs to.


Known for the "new" of the new coronavirusViral family classificationBelongs toIt means a new pathogen.That is, the new coronavirusCoronavirus familyIt means a new pathogen belonging to (or its subclass).There is no intention of a completely unknown new pathogen. The use of the word "new XX" was introduced in 2015WHOIt complies with the new infectious disease naming scheme decided by.[10] [11] [12]

Historically, pathogens have often been named after location, individuals, or specific species, but these practices are no longer endorsed by WHO.[10] [11] [12]

The permanent official names of viruses and diseases are, respectively.ICTVとWHO OfInternational Classification of Diseases (ICD)Is determined by.

Detailed explanation


[How to use footnotes]

注 釈

  1. ^ Human coronavirus NL63 Some strains of (HCoV-NL63)New Haven Coronavirus Be careful not to confuse it because it is called (HCoV-NH).


  1. ^ a b Murray and Nadel (2010). Chapter 31.
  2. ^ a b Cunha (2010). Pp. 6–18.
  3. ^ a b Melmed (2011). P. 636
  4. ^ a b c "The 2019–2020 Novel Coronavirus (Severe Acute Respiratory Syndrome Coronavirus 2) Pandemic: A Joint American College of Academic International Medicine-World Academic Council of Emergency Medicine Multidisciplinary COVID-19 Working Group Consensus Paper". ResearchGate. 2020/5/16Browse.
  5. ^ "The 2019–2020 Novel Coronavirus (Severe Acute Respiratory Syndrome Coronavirus 2) Pandemic: A Joint American College of Academic International Medicine-World Academic Council of Emergency Medicine Multidisciplinary COVID-19 Working Group Consensus Paper". ResearchGate. 2020/5/16Browse.
  6. ^ “Coronavirus disease named Covid-19”. BBC News. https://www.bbc.com/news/world-asia-china-51466362 .
  7. ^ According to ICD-10 the disease is referred to as "2019-new coronavirus acute respiratory disease [temporary name]". It is not listed in ICD-11.
  8. ^ a b Synonyms include 2019 coronavirus pneumonia and Wuhan respiratory syndrome
  9. ^ a b "What is the new coronavirus?”. Joetsu Community Medical Center Hospital. 2021/5/21Browse.
  10. ^ a b Ghosh R, Das S. A Brief Review of the Novel Coronavirus (2019-Ncov) Outbreak. Global Journal for Research Analysis. 2020; 9 (2).
  11. ^ a b World Health Organization Best Practices for the Naming of New Human Infectious Diseases. World Health Organization. May 2015.
  12. ^ a b Budhwani, Henna; Sun, Ruoyan (2020). “Creating COVID-19 Stigma by Referencing the Novel Coronavirus as the“ Chinese virus ”on Twitter: Quantitative Analysis of Social Media Data” (English). Journal of Medical Internet Research 22 (5): e19301. two:10.2196/19301. https://www.jmir.org/2020/5/e19301/. 
  13. ^ Host jump capability may not persist
  14. ^ a b Tetsuya Mizutani, ``New species of coronavirus"Virus" Vol. 63, No. 1, p.1-6, 2013, Japanese Society of Virology, two:10.2222 / jsv.63.1.
  15. ^ Middle East Respiratory Syndrome Coronavirus (MERS-CoV); Announcement of the Coronavirus Study Group Journal of Virology, Published ahead of print 15 May 2013, doi: 10.1128 / JVI.01244-13
  16. ^ Naming of the Novel Coronavirus WHO, 28 May 2013

Related item


Sewer(Gesuido) is mainly in urban areasrainwater(Light) andsewage(Sui),地下waterwayAfter collecting with etc.Public water areaA collection of facilities and equipment for discharging to.Many such as purificationWater treatmentI do.

As rainwater, in meteorologyprecipitationAnd once it got downsnowIncludes snowmelt water that has melted due to rising temperatures, but all of themroad surfaceな どSurfaceFor those inRiver water,groundwaterExcludes those that became.

As sewageFlush toiletfromhuman wasteOr when cooking and washing at homeDomestic wastewaterFrom shops, hotels and town factories to large factoriesBusinessIndustrial wastewater fromCultivationIs excluded).


Rainwater and sewagecityTo flush out of the departmentExclusionAnd personalbusiness personUsing the sewer to flush away their own sewage is called sewage removal.Specifically, it refers to the act of pouring water into a drainage pipe.Japan OfWater Pollution Control LawFor the specific facility specified inWater quality MunicipalitiesExclusion criteria by sewerage companies such as[1]Is provided.

SewercityAt the national level, a large amount of construction costs are invested as part of infrastructure development, and even after completion, a large amount of costs are required for maintenance and renewal.Public worksIs.thereforeDeveloped countryThe more popular it is, the higher the penetration rate is.

Japanese sewerPenetrationIs 2020% as of March 3[2]Although it has achieved a considerable level, it is a low value for a developed country.Regional disparityIs very large, and urgent maintenance is required in unpopulated areas.

On the other hand, in urban areas where the penetration rate is high,ConfluenceImproved sewerage, dilapidatedPipeline facilityThere is an urgent need for the next issue, such as updating.Besides, it is far behindAdvanced processingIntroduction andIndustrial wasteDisposition as is tightSludgeRecyclingThe current situation is that many issues are still piled up, such as the promotion of.

Even in areas with well-developed sewers, the inflowing water is not always treated 100%.Torrential rainRainwater and "unknown water" of unknown origin may flow in and the treatment may not catch up.[3]..Especially frequently in recent yearsGuerrilla heavy rainThere is an urgent need to respond to.For example, as of 2008, TokyoSewer BureauSo, we designed and laid sewer pipes assuming rain with a rainfall intensity of up to 50 mm, but guerrilla rainstorms andtyphoonIn heavy rain represented by, it may exceed 100 mm. (However, exceeding this 50mm standard does not mean that more rain cannot be excluded.)

These statistical data, etc. are quite publicly available for enlightenment, and some of them are published.外部 リンクIt is shown in.

the purpose

The purpose of sewerage is mainly the following three points.

In recent years, in addition to these

Etc. are required, and they are becoming the bearers.


The history of sewerage dates back to BC.However, engineering sewage purification had to wait after modern times.


Legal classification

Sewerage businessdecreeThe system also differs from country to country, but here we will show Japan.

Sewerage according to the Sewerage Act

Decree (Sewer Act) The above definition is the total of pipeline facilities, treatment facilities, pump facilities and other complementary facilities for sewage removal.IrrigationWith drainage facilitySeptic tankexcept for.Emitted from the treatment facilitySludge TheIndustrial wasteBecomes

Public sewer
mainlyCity areaIn principle, municipalities manage sewage to eliminate and treat it.Terminal treatment plantThere are "single public sewerage" that ends in the basin and "basin-related public sewerage" that treats the basin sewerage.
Public sewerLand use planningInUrbanization promotion areaAs a general rule, because it targetsUrbanization control areaAlthough it is not available in, there are businesses to supplement it.
  • Specified Environmental Conservation Public Sewerage (Special Ring) --The purpose is to conserve water quality and improve the living environment.It may have a treatment plant or it may be connected to another sewer (public sewer or basin sewer of the same or other municipalities).
  • Specified public sewerage --When a specific business operator accounts for more than 2/3 of the planned sewage amount (Industrial parkEtc.).
Rainwater public sewer
Sewerage system managed by a local public body to eliminate only rainwater in urban areas, which discharges the rainwater into rivers or other public water areas or sea areas, or connects to basin sewerage systems.2015It was added by the revision of the law.
Basin sewer
It is a sewage system for receiving, removing, and treating sewage from multiple public sewage systems. It has a basin trunk line and a terminal treatment plant, and is managed by prefectures ()2005Currently 31 prefectures).Installed along the river basin, in addition to the prefectural management officePublic corporation,combinationIt is managed by.It does not matter what type or composition of public sewerage is accepted.
Rainwater basin sewer
It is a sewerage system for removing only rainwater from multiple public sewerage systems that have a terminal treatment plant, and has a rainwater flow control facility.2003It was added by the revision of the law.
Urban sewage
Urban洪水It is provided as a rainwater drainage channel for prevention, and in principleOpen channelIt does not have a processing facility.ExistingwaterwayIn many cases, the river is rebuilt by designating the above, and the appearance is a small river itself, which may be a place of relaxation for the residents.

Sewer similar facility

In a broad sense of sewerage businessPurification tank methodas well as the Waste treatment methodSludge is subject toGeneral wasteIs.It is mainly aimed at preserving water quality and improving the living environment in rural areas, and is managed by local governments and local unions.Basically, it has pipeline facilities and treatment facilities, and wastewater treatmentShunt typeIs.This is because the Purification Tank Act does not include factory wastewater and rainwater, but although it is a small numberConfluenceIn some cases, it will be maintained at.In most cases, only sewage treatment is carried out, but in agricultural settlement drainage projects, etc.Rainwater pipeMaintenance is also covered by the subsidy project.

The difference from sewerage is that the design standards, construction method, establishments that are allowed to treat sewage, etc. are somewhat different, but for the construction funds required for maintenance.National treasury subsidyWhichMinistryThe main difference is whether or not it is delivered.

In recent years, the facility utilization rate of treatment facilities has declined due to the declining population and the spread of water-saving equipment, and in many cases, they are integrated and connected to public sewers (the treatment facilities are abolished) for the purpose of reducing the costs of the municipalities that manage them. Yes, the number of businesses is declining.

  • Agricultural village drainage facility (agricultural collection):Ministry of AgricultureAgricultural settlement drainage business under the jurisdiction.There are many businesses, and many design guidelines and manuals are available.
  • Fishery settlement drainage facility (fishery collection):Fisheries AgencyFishery settlement drainage business under the jurisdiction.The number of projects is rather small, targeting the doggy style villages of the fishing port.
  • Forestry village drainage facility (forestry):Forestry AgencyForestry village drainage business under the jurisdiction.The target area is limited and the number of projects is small.

These three projects are collectively called "village drainage project" and are sometimes called rural sewerage.

  • Simple drainage facility: Ministry of Agriculture, Forestry and Fisheries special measures for agriculture, forestry and fisheries such as mountain village promotion
  • Small-scale collective wastewater treatment facility:Ministry of Internal Affairs and CommunicationsSmall-scale collective wastewater treatment facility maintenance project under the jurisdiction
  • Specified area domestic wastewater treatment facility (merged treatment septic tank):Ministry of the EnvironmentSpecific area domestic wastewater treatment business under the jurisdiction (Septic tank municipal maintenance promotion business)
  • Individual wastewater treatment facility (merged treatment septic tank): Individual wastewater treatment business under the jurisdiction of the Ministry of Internal Affairs and Communications
  • Community plant (regional sewerage): Ministry of the Environment's regional urine treatment facility development project.Subject to the Waste Management Law.


In addition to sewerage and similar facilities, there are various facilities and equipment that collect and eliminate sewage, etc., and some of them are listed below.

  • Abatement facility: It is installed by businesses that use public sewerage, and many have a subsidy system for municipalities.The problem is that the treated water tends to be easy to manage because it flows into the sewer.
  • BusinessWastewater treatment facility: Discharges directly to public water bodies,工場Etc.Water Pollution Control LawThere is an obligation to install it in the specific facility specified in.There are various scales and management levels.
  • Merged treatment septic tank (individual management): There are large-scale corporation-installed ones used in commercial facilities, etc., and those prepared by individuals for the treatment of sewage in houses before the sewerage system is constructed.

Incidentally,Human waste treatment facilityIs very different from sewerage and similar facilities in that it does not have pipeline facilities, but it has much in common in terms of treatment processes.

Exclusion method

It is divided into two parts depending on how the pipeline for removing rainwater and sewage is constructed, and each has its own characteristics.


Sewage and rainwater are collected in the same pipeline, purified and discharged together.It is often found in cities that started maintenance relatively early, especiallyOsakaとAmagasaki98.96% of the laying extension is a confluence pipe.

  • Since there is only one merging pipe to be buried, construction is easier and cheaper than the diversion type.
  • When it rains, the sudden increase in sewage is discharged only by untreated or simple treatment.Therefore, due to the mixed sewageWater pollutionOccurs.The sewage discharged in this way is called combined sewer overflow (CSO).
  • On the contrary, the initialRainfallincludeNon-point pollution sourceIt is possible to block and dispose of pollutants derived from.
  • As a countermeasure against the above, construction of rainwater retention basins, rainwater screens, swirls, etc. is being promoted.
    • Manhole cover,GutterThere is a drainage hole for removing rainwater, and there is an odor from the pipeline.pestThere is a problem due to.Especially when the pump is operatingStenchThere are many complaints about.

Shunt type

Sewage and rainwater are collected in separate pipelines, and the rainwater remains as it is, and the sewage is purified and discharged.This method is used for the newly constructed sewerage system.

  • Since there are two pipes to be buried, a sewage pipe and a rainwater pipe, the construction cost is higher than that of the combined type.
  • Since the sewage pipe is smaller than the confluence pipe, it is often difficult for people to enter and clean or inspect it.
  • In principle, there is no dilution of sewage due to precipitation, soflow-Water qualityThe purification process can be performed stably without any fluctuation.
  • On the contrary, in the jurisdiction due to heavy rainSedimentIt is difficult to expect natural removal of the material, and cleaning is required.
    • However, in reality, there are many cases in which precipitation and groundwater are mixed to some extent (referred to as invading water or unknown water), which affects water treatment.Causes include incorrect connection of rainwater pipes to sewage pipes, intrusion of groundwater into damaged sewage pipes and sewage pipes, and insufficient sealing of manholes and lids.
  • If sewage is accidentally connected to a storm drain, the sewage may flow into the river, requiring proper construction and inspection.[Note 1].

Pipeline facility

It connects the source of sewage and the exclusion destination, and is a waterway for flowing water.パ イ プWith a pipe that isPumping stationIt is composed of other ancillary equipment.

The sewage pipes that are laid out in a mesh pattern in the urban area are just like the city.静脈AndPublic financeIs.But its durability is that of urban residentspublicIt depends on the mind.

Collection method

To the waterPhysical energyIt is divided into a natural flow type, a vacuum type, and a pressure type according to the way of giving, and each is used.Tube typeAnd there are differences in incidental equipment.In some cases, the pressure type and the pressure feeding type are separated, or the vacuum type and the pressure feeding type are combined to form a pressure type.Here, it is classified according to the method of obtaining energy (gravity, atmospheric pressure, mechanical power).

Natural flow type

Classic,重力A method of letting sewage flow down using.Strict watertight pipelines are not required and the structure of the culverts is relatively simple, but a design that suppresses the increase in burial depth that causes an increase in construction costs is required while ensuring the flow velocity to prevent the accumulation of sediment.Therefore, the number of restrictions on topographical conditions greatly affects the construction cost.It is applied from large scale to small scale and is mainstream.

Techniques for controlling the relationship between gravity and water have been accumulated, and there are many examples of partially adopting the natural flow method in the vacuum type and pressure type described later.

Vacuum type

vacuumCalled sewerage system, vacuum sewage collection system, vacuum sewage,air tightnessHigh, vacuum station (Relay pumping station), A vacuum tube, and a vacuum valve unit (valve mass) for each household.In the vacuum tube, the line is decompressed by the exhaust at the station, and it remains as it is.Negative pressureIs kept in.On the other hand, sewage from homes flows into and is stored in the vacuum valve unit under natural flow.Due to rising water levelpressureSwitch orフ ロ ー トWhen is activated, there is no mechanical mechanism电源The vacuum valve is opened and closed, and the sewage is sucked into the pipeline and collected at the station.

It is less affected by terrain conditions than the natural flow type, the installation cost is cheap, and it is generally flat and soft.groundIt is often used in the area of.In addition, no power supply is required except for the vacuum station (a battery may be required for the abnormality notification device of the vacuum valve unit).For tube typepolyethylene(PE) For pipes and vacuum sewageVinyl chloride (PVC) tubing is used, especially polyethylene tubingShockproofThis is currently the mainstream because of its high properties and long life.Agricultural village drainage, special ring sewage, special public sewerIt is a collection system suitable for medium to small scale.In recent years, vacuum stations are buried under the road, are compact, and are cheaper than before, so even small-scale collection has become cost-effective.Therefore, it is often adopted as a collection method for areas where "sewerage maintenance remains", which is difficult to collect by the natural flow method, mainly in local governments with a high sewerage penetration rate and good finances.It is being adopted in places where private land is lower than roads, in areas where it is difficult to lay collection pipes in private houses along national roads, and in land subsidence areas. Chuetsu EarthquakeIn some cases, it was adopted for the main restoration of the disaster area in Japan, and after thatChuetsu-oki EarthquakeIt showed high earthquake resistance such as no pipeline damage.Great East Japan Earthquake Then, in many vacuum-type adopted areas, mainly in the severe earthquake area of ​​Miyagi prefecture, the polyethylene pipeline was undamaged and the power supply was scarce. Despite the damage caused, it has been restored for a short period of time.I was impressed once again that the system has excellent earthquake resistance.

The negative pressure in the vacuum sewage pipeline is -25 to 70 kPa.The limit of sucking and pumping only sewage with this negative pressure is from about 2 m to a maximum of about 7 m on the earth.In the pipeline, the sewage is mixed with air and has a low specific gravity.流体It becomes a (gas-liquid mixture) and forms a two-phase flow, climbing and overcoming an ascending slope (standard 30 cm, maximum 100 cm) called "lift".The downstream pipeline of the lift generally consists of a downward slope of 2 ‰ (1 to 3 ‰), and flows down naturally even after gas-liquid separation. In the case of a 2 ‰ gradient, lifts on flat terrain will be installed every 150m.The lift portion has a structure that allows the backflow of gas but prevents the backflow of liquid.The sewage that did not reach the station with a single suction is also supported at the bottom of the pipeline, and it is possible to wait for the opportunity to be boosted by the gas-liquid mixture that has flowed in from another vacuum valve unit.In this way, the vacuum system is equipped with a mechanism for collecting sewage by making full use of advanced hydraulic engineering techniques.

Pressure type, pressure feed type

Smallunderwater pumpA method of pumping sewage from each household by installing a large number of sewage.The pump was equipped with crushing bladesgrinderPumps are often used.Although it costs a lot of money to install, power and maintain the pump, it has the highest degree of freedom in laying and can handle even the steepest terrain.For partial and small scale.

In the standard design method, when maintenance is difficult due to natural flow type or vacuum type due to construction restrictions, a pumping pipeline is partially adopted (a long distance of several km or more is sometimes called a pumping type in particular. ).A system that expands this and pumps from sewage mass to sewage mains and treatment plants in units of one to several households will be pressure sewerage.It has a proven track record on steep slopes and flat terrain where small waterways run vertically and horizontally.

In the pumping pipeline, there is less chance of air dissolving in the sewage, socorruptionbyHydrogen sulfide,Organic acidOr to the inside of the pipelineMagnesium ammonium phosphate There is a problem such as precipitation of (MAP) etc., so it can be put into sewage.ozoneな どOxidantMeasures such as injection of pigging and regular pig cleaning are taken.


As a general rule, pipes are used except for some rainwater.culvertIn general, the term "sewage" often refers to a pipe.It is laid on the road surface, rivers, and underground of houses, making it difficult to check from the outside, and the types of pipes used and construction methods vary greatly with age.Therefore, the laying age of the target culvert is an important confirmation item for management, cleaning, and renewal.

Tube type

There are roughly two types: rigid pipes and flexible pipes.Hard vinyl chloride pipes are most often used as sewer pipe materials for natural flow, and various pipe types are used depending on the application.In generalJapan Sewerage AssociationStandard (JSWAS) products are used (the alphabet of symbols is the same as JIS code)

  • 硬質Vinyl chloridePipe (VU pipe): The "VP pipe" for waterworks, which is subject to internal pressure, is called a V "U" pipe because it is unpressurized. VP pipes are widely used as sewage pumping pipe materials even in sewers, but they do not comply with JSWAS.In the water supply field, impact-resistant resin (HIVP) with a long socket and a detachment prevention joint is treated as a level 2 durable pipe material for major trunk lines, but compared to polyethylene pipes for sewerage (JSWAS K-14). Generally, it is inferior in earthquake resistance.There are many accident cases even in recent earthquakes, and it is not suitable for pressure pipelines for sewerage applications.
    • Hard vinyl chloride pipe (K-1)
    • Hard vinyl chloride oval tube (K-3)
    • Ribbed hard vinyl chloride pipe (K-13): Although it is thinribReinforced withCrushed stoneBy using it as a basisLiquefactionCan build a strong pipeline.Even in the Great East Japan Earthquake, the liquefaction damage situation is different between the quarry foundation and the other areas.
    • Rigid PVC pipe for propulsion method (K-6)
  • Reinforced plasticTube (FRPM tube): Abbreviation for Fiberglass Reinforced Plastic Mortar.
    • Reinforced plastic composite pipe (K-2): A pipe material used for large-diameter pipes that flow naturally.
    • Reinforced plastic composite tube for interpolation (K-16)
  • polyethylenePipe (PE pipe): A flexible and earthquake-resistant pipe material that is widely used in the gas and water fields in Japan.Generally, the connection is made by "fusion", which is EF-electrofusion- (electric fusion) connection or butt fusion connection.
    • (K-14): It is extremely excellent in earthquake resistance and corrosion resistance, and is increasingly being used in place of ductile cast iron pipes, especially in the small and medium diameter class.The disadvantage is that it is expensive with a medium diameter (φ250) or more, but it is cheap because it can be used for a long time, and it has become the "mainstream" of pressure pipes mainly in Europe.High-density polyethylene pipe (HDPE pipe) is a high-performance product made of a different material from the general PE pipe used in waterworks in the past.Mainly used for sewage / sludge pumping, vacuum type, steep slopes, etc. Many products conform to ISO standards.The service life is generally said to be 100 years or more, and it can be said that it is an extremely economical pipe type from the viewpoint of LCC including renewal.It is known to have extremely high seismic resistance in the Northern Miyagi Prefecture Earthquake, the Chuetsu-oki Earthquake, and the Great East Japan Earthquake.
    • Polyethylene pipe with ribs for sewerage (K-15): A large-diameter pipe (about 3000) for natural flow, which is a Howell pipe (developed in Germany. Hollow ribs are provided on the outer wall, the inner surface is smooth and has excellent pressure resistance). Typical.
  • Ductile cast ironPipe (DCIP): It has a good track record in water supply, and is most often used in pressure pipe types in sewerage.However, in the curved part and the gas phase part in the pipecorrosionThere are many damage accidents, and the main focus is shifting to interior painted products.This is against corrosion and electrolytic corrosionservice lifeHas improved to about 20-25 years (40 years for waterworks), andEarthquake resistanceThe NS type, which has excellent withdrawal prevention properties, has become widespread.
    • Ductile cast iron pipe (G-1)
    • Ductile cast iron pipe for propulsion method (G-2)
  • Reinforced concreteTubes: Mainly medium to large diameter tubes.Due to the manufacturing methodcementCompaction by vibration (bicon),Centrifugal forceDue to (Hume pipe), The latter is especially called centrifugal reinforced concrete pipe.Bicon is easy to handle on-site casting and special shapes, but Hume pipe is excellent as a standard product. (The promised "Pile in a vacant lot" in the mangaClay pipeIs this.Sewerage maintenance was promotedHigh growth periodIt was a familiar sight to the generation, but in modern times its share of pipe materials has dropped considerably.)
    • Reinforced concrete pipe (A-1)
    • Reinforced concrete pipe for propulsion method (A-2)
    • Reinforced concrete oval pipe (A-5)
    • Small diameter pipe propulsion methodReinforced concrete pipe (A-6)
    • Glass fiber reinforced concrete pipe for propulsion method (A-8)
    • Reinforced concrete pipe with stand (A-9)
  • Resin concreteTube: Hume pipe cementUnsaturatedpolyesterA substitute for resin.The difference between cement and resin is directly reflected in the performance difference, which is strong against acid, hard to wear, and has high earthquake resistance.It is lightweight and has good workability, so it is effective in shortening the construction period.Watertightness and smoothness of the inner surface are also high.It's all good, but of course the price is high.
    • Resin concrete pipe (K-11)
    • Resin concrete pipe for propulsion method (K-12)
  • Clay pipe(Ceramic pipe) (Ceramic pipe): Used from the early Meiji era, especially household mounting pipes, etc.brickIt occupied most of the small-diameter pipelines that were difficult to construct by stacking until around 40, when PVC pipes became widespread.Tokoname wareIt is still in demand today as a destination for promoting local industries and recycling sludge incineration ash.
    • Ceramic egg-shaped tube (R-1)
    • Pottery tube (R-2)
    • Ceramic pipe for propulsion method (R-3)
  • Steel pipe: Since the number of standards and sizes is much larger than other steel products, it was often used in the so-called distribution industry such as for piping, but in recent years it has also been used for sewerage.In addition, it is not established in the Japan Sewerage Association Standard (JSWAS), and it is an original standard.Japan Water Works AssociationIt is only established in the standard (JWWA).
  • Others: Apart from the image of the tube,Precast concreteProducts etc.
    • Box culvert (Culvert means culvert): A short box with a square cross section, often used for trunk lines under roads.It is also called "Hakodori" because it is square.
    • Arch culvert: A culvert with an arched and semi-cylindrical cross section.
    • Segment: A part of the pipe wall used in the shield tunneling method.
    • In the case of a special deformed pipe, it may be constructed on site (cast-in-place construction method).

Laying method

It seems that the construction of long and narrow equipment, not limited to sewerage, is called laying.Depending on the construction method, it is closely related to a specific pipe type.

Excavation method
It is the most basic construction method and has a long history.Even in the non-excavation method, the shaft is based on the excavation method.
First, steel sheet piles are lined up on the ground and driven in, and a groove is made by excavating the space.Make a foundation with crushed stone or cement on the bottom, and assemble a pipe on it.It is the most flexible in terms of pipe type, laying length, and surrounding conditions, but when laying under the road, the range and duration of road closures are the longest.For this reason, non-cutting methods are often used on highways with heavy traffic.
Shield construction method
A construction method often used in the construction of subways, which is used for large-scale trunk lines with a diameter of over 1.35 m.Segments are lined up on the inner wall dug by the shield machine, and a pipe is built on the spot.
Propulsion method
Developed in the United States at the end of the 19th century, it has been adopted for sewerage since 28.[8].
First, two vertical holes (starting shaft and reaching shaft) are installed up to the laying depth of the pipe, and they are large.hydraulicjackIs placed at the bottom of the starting shaft.Then on both endsscrewThe special pipe for the propulsion method, which has been cut, is pushed into the ground hydraulically toward the reaching shaft.After pushing one, screw the next pipe back and connect, and repeat this.When the tip reaches the reaching shaft, the hydraulic jack will be relocated here and propulsion will start toward the next reaching shaft as a new starting shaft.In the old starting shaftmanholeEtc. are constructed.
It is an effective construction method when the depth of the cloth design line is large or there is a building on the ground surface, and there is little noise and vibration.The area occupied by the surface of the earth is small, and the impact on traffic can be suppressed.Various improved methods have been put into practical use for excavation at the tip and discharge of earth and sand, and the scope of application has been expanded and the accuracy has been improved.
Blade edge propulsion method
In the conventional method, a cutter (blade edge) is attached to the leading pipe, and a person enters the pipe to perform excavation work at the tip.
Semi-shield tunneling method (sealed / mechanical propulsion method)
Around 40, it was developed by introducing the shield method technology.A digger is installed at the tip and the inside of the pipe is sealed.There are muddy water type, soil pressure type, and mud concentration type.
Small diameter pipe propulsion method
A propulsion pipe (a thin guide pipe in the two-step method) is connected to the tip conductor (face) and operated remotely from the starting shaft.Depending on the pipe type, there are high load capacity method, low load capacity method, steel sheath pipe method, and depending on the excavation / soil removal / burial method, press-fitting method, auger method, muddy water / mud pressure method, boring method (steel sheath pipe). There is a method only).
Reconstruction promotion method
A construction method dedicated to renewing pipes that has recently begun to spread.Propulsion while crushing old pipes with a digger.

Pumping station

In order to discharge sewage regardless of the collection method, it is necessary to pump the water to a position sufficiently higher than the water surface of the discharge destination.pump(Except for some natural flow type, which is blessed with terrain conditions).

In sewagePotential energyThe number is the largest for the purpose of giving.
In the natural flow type, as the laying spreads, if the slope of the pipe is simply extended, it will become very deep underground or conversely jump out of the ground surface.Therefore, the relay pumping station and the pipe are combined to form a pipe that looks like a saw tooth when viewed from the side, and the laying distance is extended while maintaining a certain depth.
manholePumping station
A simple relay pumping station where a pump is simply installed in a manhole.
Drainage pumping station (drainage pumping station)
A pumping station for draining rainwater or unobstructed merged sewage into public water bodies.
In small rivers and waterways that connect to large rivers, when the water level of large rivers rises and there is a risk of backflow,Sluice,Gutter, Close the gutter tube to prevent this.At this time, what is needed is a drainage facility to eliminate inland water beyond the water level difference.A drainage pumping station, which is a river management facility, will be installed in rivers and drainage channels, and a drainage pumping station will be installed in sewerage.Urban sewageThere is also an intermediate existence such as, and management is also rationally distributed between the river sector and the sewerage sector (because both are under the jurisdiction of the Ministry of Land, Infrastructure, Transport and Tourism).
Always wait at the drainage facility except when it rainsTorrential rainImmediate action is required for such a sudden increase in flow rate.For this reason, a large pump called an aerial standby type has been developed, which can start idling before rainfall and stand by as it is, depending on the weather conditions.
Off-site pumping station
It is a pumping station for sending sewage to the treatment equipment at the terminal treatment plant, and can be said to be the last relay pumping station.It is often installed in the treatment plant, in which case it is called the on-site pumping station and is not included in the pipeline facility.

Coordination facility

Following the revision of the Sewerage Law in 16, installation is being promoted mainly to curb and eliminate the discharge of untreated sewage from combined sewerage systems.

Storage facility
Temporarily store sewage (shielded sewage) that exceeds the sewage treatment capacity of the treatment plant, and return it to the sewage pipe after it rains.
How effective it is to confine and store the merged sewage is greatly affected by rainfall and pipeline conditions, so it should be combined with the examination of storage capacity.simulationThe use of technique is progressing.
Rainwater infiltration facility
Rainwater before merging with sewage is infiltrated into the soil to reduce the amount of wastewater discharged into the merging pipe.
Most of the urban areas with excessive paving are on the surface with a small penetration coefficient.In addition, as a result of promoting the elimination of rainwater to prevent urban flood damage, even the precipitation that should have been infiltrated into the soil and used as groundwater was used as sewage.In order to deal with this, a rainwater outflow control model has been put into practical use, in which the outflow water from the road surface is received by the infiltration mass, collected in the infiltration manhole by the infiltration pipe in the infiltration trench, and only the overflow water is discharged to the confluence pipe. There is.In the sewerage plan, it will affect the planned amount of water in the pipeline facility, so make a permeation pipe route plan and consider it.
Simple processing facility
Before draining the sewage, use a screen to remove dust (remove impurities)disinfectiondo.
When the rain that begins to fall in the city area eventually becomes runoff, it comes from the atmosphere, roofs, and road surfaces.SootIt is often washed away and taken in (non-point pollution).This is called initial rainfall (initial flash water).Shunt typeEven rainwater facilities in sewers should be treated.Equipment that can efficiently treat the amount of water that changes suddenly with a small installation area is required.
Blocking equipment
Rainwater discharge with improved weir height and structure to increase the amount sent to the treatment facility.
rainwaterRegulating pond
Although it is not a sewerage facility, it is effective in improving sewerage because it reduces the amount of rainwater.


Masu (Masu, Masu)
It can be divided into public installation (public, installation) that is installed by a business operator and connected to a pipe and a mounting pipe, and private installation (in-house) that collects sewage and rainwater before connecting to the public installation. It is not directly related to the above difference (there are large private establishments and small public establishments).In the case of rainwater, since it is related to the side ditch, rainwater with a structure different from that of sewage is sometimes used.
Manhole (manhole)
It is provided at regular intervals for inspection and cleaning of pipes.In particular, it can be said that it is indispensable at the bending point of the pipeline and the confluence of multiple pipelines.
Manhole pumping station
 Abbreviation is MP or manpo.A simple pumping station with one or two submersible pumps installed inside a large manhole.Treated as part of the culvert.
Vacuum station
 In public sewage, it is called a "relay pumping station".Abbreviation is STN.Vacuum sewer system collection facility.It has a vacuum pump and is the only power supply facility for the system, to which a vacuum drain is connected.
Flip down
U-shaped to dive under rivers and subways to crosssiphonConstruction.Precipitates tend to collect on the bottom, and regular cleaning is essential.
Energy reduction work
SteepterrainIf the flow velocity of the sewage rises too much due to factors such aswear,Water pressureThe drainage pipe is damaged by itself.Waterways and spiral shafts with obstacles are provided to prevent this.

Processing facility

Officially a terminal treatment plant, but generallySewage treatment plantis called.Recently, nicknames such as purification center and water reclamation center are often given.The abbreviation on the drawing is T (abbreviation for Treatment) surrounded by □.

The capacity of the treatment facility is displayed in cubic meters daily for daily average, daily maximum and hourly maximum water loads.These are called design loads or design capacities and are determined as part of a sewerage plan based on the planned amount of sewage.


The progress of sewerage maintenance, etc.populationExpressed as a percentage ofindexSo, the country aggregates.There are several types depending on the target, and some do not depend on the population.Since the population data uses the Basic Resident Register population, foreigners are not included.Prefectural and municipal level values, which are the basis of national tabulation, are also partially published.


  • Sewerage treatment population penetration rate: The Ministry of Land, Infrastructure, Transport and Tourism has published a total, and the term “sewerage penetration rate” refers to this.Note that this is the rate of the population in the sewerage treatment area (the population that can eliminate domestic wastewater into the sewer), not the actual utilization rate.Often confused in the press.The actual utilization rate is called the connection rate and yield, and there are large regional differences, which is about 8% of the penetration rate nationwide.
  • Highly treated population penetration rate: The percentage of the total population of the area where advanced treatment is carried out.After all it is not the number actually used.
  • Urban inundation countermeasure achievement rate: 5 years probability of the target area for urban inundation countermeasure development(I.e.The area where the maintenance has been completed is expressed as a percentage of the area.
  • Sewerage environmental conservation rate: An index unique to the Ministry of Land, Infrastructure, Transport and Tourism.The progress of three measures related to water quality conservation in public water bodies is shown.In addition to the sewerage treatment population penetration rate and the advanced treatment population penetration rate, the penetration rate of the merger improvement measures in the merged sewerage development area is tabulated for the areas required from the viewpoint of improving the water environment.
  • Sewage treatment population penetration rate: Sewerage with separate jurisdictionSimilar facilitiesIt is calculated from the number of people who have spread the area and the population of septic tanks for merger treatment, and the total is started from 8 (1996), and it is called the sewage treatment facility maintenance rate until 14 (2002). did.The Ministry of Agriculture, Forestry and Fisheries, the Ministry of Land, Infrastructure, Transport and Tourism, and the Ministry of the Environment jointly announce it in late August every year.The reason why the population of single treatment septic tanks is excluded is that the emphasis is on domestic wastewater treatment.
  • Flush toilet rate: It is used synonymously with the sewerage penetration rate, and the rate of people using flush toilets includes the septic tank population, so be careful as the definition has not been determined.According to the results of the Ministry of the Environment's survey on the actual condition of general waste treatment, the latter means.
    • The flushed population of the Ministry of the Environment is the public sewerage population and the Komipura population.Septic tankIt is the sum of the population (combined septic tank population + single septic tank population), and also includes household septic tanks.Since septic tank sludge is included in the collection target of the human waste treatment plant, this part tends to lack statistical rigor.

Current status

  • Sewerage treatment population penetration rate (first year of Reiwa): 79.7% (sewerage user population ÷ total population)[9][2]
    • Highly processed population penetration rate: 56.3%[10]
    • Achievement rate of urban inundation measures: 52.7%
    • Sewerage environmental conservation rate: 31.4%
  • Sewage treatment population penetration rate (first year of Reiwa)[11] : 91.7%-Independent septic tank is not included as it does not treat domestic wastewater
    • Sewerage: 79.7%
    • Septic tank: 9.3%
    • Agricultural collection and excretion: 2.6%
    • Komipla: 0.2%

In addition, according to the aggregation (16) of the prefectural sewerage concept (basic plan for maintenance), the final estimated penetration rate is 88%.

Ranking by prefecture

By prefecture, the top five penetration rates are Tokyo, Osaka, Kanagawa, Saitama, and Aichi.The worst 5 are Tokushima prefecture, Wakayama prefecture, Kochi prefecture, Kagoshima prefecture, Kagawa prefecture.

Disaster prevention (earthquake resistance, manhole toilet)

Due to the damage to sewerage facilities caused by the recent major earthquakes, treatment facilities and pipeline facilities are being made earthquake-resistant.In addition, since the problem of toilets was serious at evacuation sites in the past disasters, the Ministry of Land, Infrastructure, Transport and Tourism stated in the "Sewerage BCP Formulation Manual-Second Edition- (Earthquake / Tsunami Edition)".Manhole toiletIt organizes the necessity of.In preparation for future disasters, it is necessary to take cross-cutting efforts not only by the department in charge of sewerage but also by the department in charge of disaster prevention.

Examples of advanced businesses

Problems / Issues

The sewerage business is an important public service and social infrastructure in social life, but on the other hand, it has various problems and issues.


It is very important to develop the sewerage system together with other sewage treatment facilities (agricultural settlement drainage facilities, merged treatment septic tanks, etc.) in consideration of its merits and demerits while considering economic efficiency and regional characteristics.Currently, each prefecture has formulated a "prefecture concept" for sewage treatment projects, and although consideration is being given to selecting the most suitable sewage treatment method,Water supply businessSince the cost required for wastewater treatment is higher than the cost of water purification treatment, it puts pressure on the finances of the local governments that manage it, and the burden on the residents who use it has to be high.

Regional disparity

Since the development of sewerage is greatly affected by the financial situation and topographical characteristics of local governments, there are large regional disparities.

For example, the penetration rate for each basic municipalityTokyo,KanagawaIs about 100%, whileTokushimaIs in the 30% range (as of the end of 29)West JapanIs low,East JapanTends to be high).Looking at each municipality, the smaller the population, the lower the penetration rate, which is below the national average of 10 or less.

However, it should be noted that because there are sewerage-like facilities and merged treatment septic tanks, it does not necessarily mean that the penetration rate is low = sewage treatment is not progressing, and the sewage treatment population penetration rate as of the end of 30. Is 60% in Wakayama prefecture and 57% in Tokushima prefecture.[14]..On the contrary, this also means that a high penetration rate does not necessarily mean that it is good (see below).


When constructing a new sewerage system, the project implementation entity (municipalities) will carry out construction work up to public sewage.For drainage construction cost of the house is the personal burden, 3 of which generally is that (Sewerage Law are required to connect to the prospect of the 11-year Article 3 from the date of publication of the start of service by the sewer method is used for connection to the sewer ) However, it may be left unattended for economic reasons, which is a factor that does not increase the washing rate.When not connected to the sewer, domestic wastewater discharged from houses built before the compulsory combined treatment septic tank is spilled untreated, which is one of the causes of river pollution.In the case of new construction or renovation, the building manager will be asked to confirm the building, but in principle, confirm the application for treating sewage by a method other than sewerage, even though it is located in the sewerage treatment area. You cannot receive it (Article 10 of the Sewerage Law).

Fraudulent penetration rate

The local government declares the sewerage penetration rate to the national government, which isLocal allocation taxIt becomes the grant calculation standard.Okayama CityFalsely declared the penetration rate and received an extra 20 billion yen, and was ordered by the government to pay 41 billion yen.Since the citizens of Okayama lost 21 billion yen, they are seeking compensation for damages from the staff at that time who were involved in the false declaration.

Abatement facility

Very often, it is mistakenly described as an "excluded facility," and there are even cases where it is misunderstood that there is no obligation based on this error.

The abatement facility is a "facility necessary to remove obstacles caused by sewage" to the sewerage system, and the user is responsible for installing and managing the sewerage system, which is a shared facility of society, in order to prevent it from being damaged. Is what you do.

Malicious sewage, that is, the act of pouring in toxic substances of types and amounts that exceed the detoxification capacity of sewage treatment plants, and substances / objects that block or destroy pipes without removing them (for example).Hot waterIt also includes the act of pouring in as it is. ) Is a crime against all other sewerage users and a crime against all those who use the public water area of ​​the discharge destination.

It is also discharged from homes and businessesmercuryHazardous metals such asBiomagnificationBe sewageSludge OfcompostIt hinders effective use of such products.

Since the sewer is an underdrain, the authorities cannot sufficiently monitor the wastewater from the business establishment.Also, if you connect to the sewer, the drainage will be cracked down.Health centerIs transferred to the sewerage manager, but for the sewerage manager, the user is a customer who pays the sewerage fee, so a strong crackdown cannot be made.Sewerage managers nationwide for usersAccusationThere is no example of such disposal.In the basin sewerage system that spans more municipalities, management responsibilities become ambiguous and guidance becomes sparse.

In addition, the business operator which has the abatement facilityHazardous facility management managerMust be appointed and appropriate maintenance must be carried out.

Sludge treatment

A large amount of sewage treatmentSludgeOccurs.London TreatyEven in Japan due to ratificationWaste treatment methodHas been amended. Sludge removed from public sewers since April 2007Ocean inputDisposal has been totally banned, and now the entire amount of sewage sludge is treated on land.

Many sewage sludgeIndustrial wasteAlthough it is disposed of in landfill asFinal disposal siteIs running out and a lot of industrial wasteIllegal dumpingSewage sludge can be seen in the dumped material of the incident.

As a countermeasure,Solid fuelChangeMolten slagAlthough it has been converted, it requires a large amount of construction and maintenance costs, and is progressing only in some large cities.In addition, products such as blocks manufactured also have quality problems such as strength, and their effective use has not progressed very much.Incineration ash in recent yearsconcreteUsed as a substitute for the raw material sand,cementAs a raw materialRecyclingThe rate is improving.

Sewage sludge is a large amountfertilizerContains ingredients andCompostingEffective use for compost, etc. is the cheapest and easiest method, but in JapanFertilizer control lawHazardous metal content standards in Japan are strict, and it is difficult if a large amount of factory wastewater is taken in.[Note 2].

In addition, it is contained in sewage sludgeorganic matterThefermentationLet mebiomassBecome fuelmethane gasTake out,Fixed price purchase systemEfforts to reduce sludge are spreading[15].

Aging facility

Pipeline facilities are exposed to harsh physical (earth pressure, vehicle weight, water pressure, wear), chemical (corrosion due to hydrogen sulfide, etc.) and biological (tree roots invade for water) environment for a long period of time. The pipeline, which has been exposed for several decades since its laying, has deteriorated, and as a result of drawing in the surrounding earth and sand, there have been a series of cases nationwide that form cavities and cause road surface collapse accidents (17). 6600 cases).There have also been accidents in which cars and people are falling while passing by, and maintenance is becoming more important and maintenance costs are also increasing significantly.[16]..This is because postwar Japanese sewer pipes are vulnerable to corrosion instead of ceramic pipes and stone pipes.Hume pipeと 呼 ば れ るReinforced concreteDue to the use of materials made of.Inside the sewer pipeHydrogen sulfideCorrosive gas such as, etc. is likely to be generated, and if sewage accumulates, concrete may corrode and be damaged.Currently, many local governments rehabilitate the inner surface of pipeline facilities as a measure to extend the service life, but when the pipeline is replaced, it tends to cost more than when it is newly installed, such as installing a temporary bypass pipe.Although there is a national subsidy for the construction of sewers, many local governments still struggle to redeem the bonds used to finance the national treasury subsidy.In the future, it is expected that many local governments will have difficulty in increasing and generating renewal costs.

In addition,Great Hanshin EarthquakeIn, the treatment facility recovered relatively quickly, but the pipeline facility took a long time to recover.EarthquakeVulnerability to disasters such as these is also regarded as a problem.

Population decline

The sewerage business is a business that develops facilities in advance, earns usage fees as compensation for the sewage treatment service provided at the facility, and recovers expenses, but the amount of revenue water decreases due to population decline nationwide. Many local governments are facing the problem of a decrease in rental income.

Unauthorized use of well water users

Sewerage charges are linked to water usage, sowellThe amount of water that is discharged into the sewer is not reflected in the price.For this reason, procedures such as attaching a meter to the well water pumping pipe and having the local government approve the fixed amount of usage are required, but there are limits to on-site inspections of private land and facilities, and it is often fraudulent. Acts are also performed[17][18]..As an example of high charges for fraudulent activity by local governmentsOtsu City Royal Oak Hotel Spa & Gardens(Operating company is2020In 4 monthbankruptcyThere is a usage fee of 13100 million yen and a fine of 39500 million yen for the application).The hotel has been illegally using the sewer for 30 years, but the ones that were subject to collection werePrescriptionOnly 5 years excluding minutes[19].

World sewerage situation

The sewerage penetration rate in Japan is not high only in developed countries.However, there are still many countries in the world that do not even have sewerage plans, and the majority of the countries have reached the penetration rate, which is rather a minority.This is, for exampleUnited NationsAdvocated by "Human securityIt means that there are still many countries and regions that lack the elements to achieve.

Above all,monsoonAsia, which belongs to the climate, has a low penetration rate in many overcrowded cities, despite the environment where it is rainy, hot and humid, and there is a high need for sewerage, and underground infiltration is often used instead of sewerage.

Sewerage museums, theme parks, etc.

There is also a sewerage management body that accepts tours at some of the sewerage facilities.TokyoKodairaThe "Fureai Sewerage Museum" in Japan is the only one in Japan where you can enter the real sewer pipe.[20][21].

Book as the subject

  • Monthly sewer


[How to use footnotes]

注 釈

  1. ^ In June 2009,Oji StationToilet sewage for over 40 yearsShakujii RiverIt was discovered that it was flowing into.Shintaro IshiharaGovernorIs in TokyoJRInstructed inspections at all stations and other locations.
  2. ^ Under the Fertilizer Control Law, all fertilizers using sludge are registered fertilizers.Ministry of AgricultureSewage sludge and human fecesAct on Standardization of Agricultural and Forest Products and Appropriate Quality LabelingAccording to (JAS method)Organic JAS certification"To receive" etc.Organic fertilizerIt is said that it cannot be used as a raw material.


  1. ^ Tokyo Metropolitan Government Bureau of Sewerage:Water quality regulation related to business wastewater[Broken link]
  2. ^ a b "About the spread of sewage treatment population at the end of the first year of Reiwa”. Ministry of Land, Infrastructure, Transport and Tourism. 2021/5/30Browse.
  3. ^ Inflow of "unknown water", overflowing sewage"Nihon Keizai Shimbun" morning edition September 2018, 5 (social aspect) September 20, 2018 reading.
  4. ^ Tokyo Sewer Bureau : Mikawashima Water Reclamation Center[Broken link]
  5. ^ Nagoya City Waterworks and Sewerage Bureau:Overview of sewerage facilities[Broken link]
  6. ^ Gifu City Waterworks and Sewerage Division:Gifu City Sewerage (History)[Broken link]
  7. ^ Osaka:Overview of basin sewerage
  8. ^ Japan Sewerage Ditch Promotion Technology Association:Outline of propulsion method
  9. ^ "Sewerage data room”. Ministry of Land, Infrastructure, Transport and Tourism. 2021/3/1Browse.
  10. ^ "Advanced treatment implementation rate for creating a good water environment by prefecture”. Ministry of Land, Infrastructure, Transport and Tourism. 2021/3/1Browse.
  11. ^ "Sewage treatment population diffusion status by prefecture”. Ministry of Land, Infrastructure, Transport and Tourism. 2020/12/7Browse.
  12. ^ Tokyo Metropolitan Government Bureau of Sewerage:Sewerage ledger homepage
  13. ^ "Facility information”. Kodaira City. 2017/8/27Browse.
  14. ^ Sewage treatment population diffusion status by prefecture (PDF)
  15. ^ Biomass in sewage sludge Operates in Nakanoto Town Selles electricity to Hokuriku Electric Power Company"Nihon Keizai Shimbun" morning edition October 2017, 10 (Hokuriku Economics) Retrieved November 20, 2018.
  16. ^ Sewerage Department, Urban and Regional Development Bureau, Ministry of Land, Infrastructure, Transport and Tourism, Japan:Reconstruction of sewerage facilities, etc.
  17. ^ ""Hilltop Hotel" in Tokyo that cheats sewerage charges with detour piping”. Nihon Keizai Shimbun (May 2012, 10). 2020/5/14Browse.
  18. ^ ""Tenkaippin" Unauthorized use of sewerage 1 million yen”. J-cast (April 2013, 4). 2020/5/14Browse.
  19. ^ "Bankruptcy resort hotel charges drainage sewerage fee and fine total about 5 million yen without permission”. Kyoto Shimbun (June 2020, 5). 2020/5/14Browse.
  20. ^ Kodaira City Fureai Sewerage MuseumKodaira City homepage (viewed on December 2018, 12).
  21. ^ [Exploration Science] Fureai Sewerage Museum Visiting the real sewerage "Nikkei" morning edition November 2018, 11 (news science side).

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