Japanese experiences of Sanitation and Sewage works

History, law, organizations and present situation

Eijiro TAKASHIMANational Institute for Land and

Infrastructure Management, Japan1

Historyof Sanitation and Sewage works

in Japan

Sewage treatment plant in Tokyo metropolitan areahttp://www.gesui.metro.tokyo.jp/odekake/syorijyo/03_02.htm 2

Edo era(18th～19thcent.), Before World War Ⅱ(～１９４５)

• Edo(Tokyo) already had a population of more than a million in the 18th century.

• Human excreta in pit latrines were collected, transported and sold to farmers as fertilizer.

• Urban areas in Japan were relatively sanitary because of this recycling system.

A pit latrine in Edo era光藤俊尾・中山繁信：すまいの火と水 台所・浴室・便所の歴史、彰国社

Utilizing for farmlands http://sinyoken.sakura.ne.jp/caffee/cayomo070.htm

Transporting of excretaはばかりながら「トイレの文化」考 文芸春秋

3

• Population increased at a very high rate in urban areas.• Suburban farmlands turned into residential areas. • Production and use of chemical fertilizer increased. • Excreta from pit latrines were not being used for

farmlands.

• Excreta changed from valuable matter to waste.

After World War Ⅱ（1950～）high economic growth period

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• Municipalities had to tackle the problem of excreta disposal.• At first, collected excreta were disposed of in the sea.• To solve this problem, municipalities built treatment plants

for them.

Collecting human excreta by a vacuum truck

http://yaplog.jp/ryoyo18/archive/68

Disposing of excreta in the sea「急げ下水道」 1968年 千葉市制作 より

During the high economic growth period (2)

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• People began to use flush toilets, and human excreta were treated inefficiently by individual treatment tanks.

• People began to use synthetic detergent.• Wastewater was released directly into rivers. • Many rivers became extremely polluted.

During the high economic growth period (3)

Water pollution in urban rivershttp://www.kankyo.metro.tokyo.jp/basic/publications/scenery/water/ 6

Development of Sewerage system

• To improve environment of residential area and public waters, municipalities have quickly constructed sewerage system over the past 50 years.

• Now, sewerage system covers 80% of Japanese households.

Sewer pipehttp://www.city.akita.akita.jp/city/ws/okyakusama/gesui_shikumi/default.htm

Sewage treatment planthttp://senbokukankyo-ichikumi.org/gesui/kids.html

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Recycling of sewage sludge• Our lives have greatly improved, but we no longer use the original

excreta recycling system.• Recycling of sewage sludge has increased.• Sewage sludge utilized as fertilizer, fuel or construction materials.• It is important to make these more cost-effective.

Composting of sewage sludge A package of compostCarbonized sludge for fuelhttp://www.gesui.metro.tokyo.jp/oshi/infn0337_1.htm 8

Water quality improvement by the effect of sewerage system and advanced sewage treatment

Polluted Tama River in 1977Foam is detergent in the wastewater.

https://www.env.go.jp/policy/hakusyo/zu/eav10/eav100000000000.html

Sweetfish going upstream in 2010http://tamagawa.circlemy.com/event-03.html 9

Law, Organizations and Present situation

of Sewage works in Japan

Since 1958 when Sewerage Law was enacted,sewage works have quickly become widespreadand many organizations have been established.

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Main Points of Sewerage Law in Japan (1)

• Local governments are primarily responsible for public sewage works.

• National government directs local governments, and provides national grants and loans for construction.

• Ordinances under the law provide fundamental technical standards.

Items Values

pH 5.8 ~ 8.6

Coliform group less than 3,000 CFU/cm3

Suspended solids less than 40 mg/L

BOD5, T-N, T-P Standard values conformed to planning effluent quality that depends on the rivers etc.ex. BOD5 15, T-N 20, T-P 3 mg/L

Effluent quality standards

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• When sewer is constructed, service area must be made known to the public.

• Building owners in sewer service area must connect their buildings to sewer.

• Highly concentrated wastewater from industries is regulated to protect sewerage facilities and water quality.

Main Points of Sewerage Law in Japan (2)

Connection to sewer from a househttp://www.town.mimata.lg.jp/modules/sideMenu/index.php?cat_id=40 12

Main Points of Sewerage Law in Japan (3)

• Sewage works administration has the right to let officials inspect private facilities connected to sewer if necessary.

• Basic rules regarding sewage service charges are laid out in this law.

• The details of sewage service charges for each municipality are stipulated by local ordinances.

Legal force by government is necessary to preserve sanitation and environment.

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Organizations (1)concerned with Sewage works in Japan

• National government enacts law.manages policy, regulations,

fundamental technical standards, national grants and loans.

• Local governments(47 prefectures and 1400 municipalities)

enact local ordinances.responsible for planning, design,

construction, O&M and finance.

Ministry of Land, Infrastructure, Transport and Tourism

Sewage treatment plantIn Yokohama Cityhttp://www.city.yokohama.lg.jp/kankyo/gesui/centerinfo/01wtc/#gaiyo

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• Japan Sewage Works Agency (JS)assists technical works of local governments

which have less technical personnel.manages planning, design, construction, maintenance, R & D,

technical training, etc.

JS was established under a special law.

Organizations (2)

Small scale treatment plant Technical training 15

• Consultants• Construction companies• Plant constructors (mechanical or electric)• Material manufacturers• O&M companies (pipes or treatment facilities)

Each industry has its own association to improve technical skills and to manage public relations.

Private enterprises

Organizations (3)

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• Japan Sewage Works Association (JSWA)a network of sewerage administrations.deals with research, technical guidelines, statistics,

conferences, public relations, etc.

Technical guidelines for each field (planning, design, O&M, water quality, etc.) are discussed and written by groups of specialists from various organizations.

Organizations (4)

Example of technical guidelines and statistics 17

Financial Situation

• National grants and loans led to rapid growth in sewerage construction.

• Most of the cost for O&M and construction not from national grants should be recovered from sewage service charges.

• In areas of low population density, the cost is higher and the gap between the cost and the charge is larger.

1 euro=140 yen

Cost and charge with population density

0.0

0.5

1.0

1.5

2.0

2.5

0 20 40 60 80 100

euro

s/m

3

Population density (people/ha)

Cost (initial + running)per m3

Charge per m3

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• Japan has built huge quantities of sewerage-related assets over the past 50 years.

• Sewer pipe length is more than 11 times the earth’s circumference.• Maintenance and restoration of those will become more and more

important as they age.

Asset Management

Deteriorated pipeYearIncrease of sewer pipe assets with time 19

Conclusion• Establishment of the law and organizations

promoted sewerage system in Japan.• Still, asset management and utilization of sewage

resources present challenges.• Adequate sanitation system will be different

depending on countries’ and areas’ situation.• It is important in any case to utilize organic

matters and nutrients from humans.

Thank you for your attention.20