Japanese urbanizationand domestic wastewater management
December 15th , 2010
WEPA Dialogue in Nepal

Takatoshi Wako
Deputy Director, Water Environment Division
Environment Management Bureau, Ministry of the Environment, Japan

Night Soli Recycling Systems in Edo Era• A sanitary city unlike any other in the world,
where organics substances such as night soil and garbage werereused as suppliers of fertilizer in outlying farming village• Less epidemics in Japan comparing to modern Europe

A farmer carrying
tubs of night soilNight soil recycling systems in Edo Era
Ministry of the Environment

Source: Annual Report on the Environment2

From Edo to Tokyo• Population increase and Start of sewerage construction
Oil price shock(1973)Outbreak ofthe Pacific War(1941)End of Edo Era（1867）

Rapid economic growthStarted (1955)
End ofthe Pacific War(1945)

Transit of population in Tokyo

Yokohama: Brick-made sewer line
（1881）
Ministry of the Environment

Tokyo: Mikawa-jima Sewerage Disposal Plant（First sewerage disposal plant in Japan：1922）

3

History of Sanitary Treatment of Night Soil in Japan• Storage of night soil and utilization for agriculture(1200s～1960s)• Decreasing demand for the traditional night soil recycling systems dueto the urbanization and the spread of chemical fertilizer (1950s)• Nationwide water pollution caused social problem(the late 1960’s～)

Ministry of the Environment

Trends of waterborne disease rates in Japan

4

Water Pollution of Tokyo in 1970’s

Tokyo Bay in 1970’s

Ministry of the Environment

A river of Tokyoin 1970’s

The Kanda river(Tokyo) in 1970’s

Photo Credit : Environmental Bureau of the Tokyo Metropolitan Government 5

Night Soil Treatment andDomestic Wastewater Treatment Systems in Japan

Ministry of the Environment

6

System of Sewerage Projects Based on the Sewerage Service Act.
• Purpose of the Projects◆

Sound development of cities, prevention of floods, securing of publicsanitation, and water quality preservation in public water areas• Implementation system
National government: Approval of project plans, subsidization, etc.
◆ Prefectures: Construction and management of river-basin sewerage◆ Municipalities: Construction and management of public sewerage◆• Plans on sewerage
Comprehensive plan on river-basin sewerage construction◆ Plans of prefectural governments:◆Master plans for deciding appropriate wastewater treatment methods

Plans on measures against rainwater◆ Sewage sludge treatment comprehensive plan◆• Financial system
Financial system of sewerage projects
Ministry ofthe Environment
based
on governmental subsidies, user’s fee, etc.
◆7

Mechanism of Japan’s Sewerage• Combined sewerage
Adopted in Japan because urgent issues in the past were flood prevention
and improvement of living environments in big cities like Tokyo wheresewerage construction had been started since early times• Separate Sewerage
Adopted since water quality preservation in public water areas was definedas one of the goals in the Sewerage Service Act was revised in 1970.

SidewalkRoad

Wastewater and Rainwater

Combined sewerage
Ministry of the Environment

Sidewalk

RoadWastewater
Rainwater

Separate sewerage
8River-basin Sewerage and Public Sewerage
Public Sewerage(constructed by municipal governments)

River-basin Sewerage(constructed by prefectural governments)

PublicSewerage

PublicSewerage

Sewage treatment plant

PublicSewerage‘B’ City ‘A’ City
‘D’ City ‘C’ City

PublicSewerageRiver-basinSewerage
Sewage treatment plant

Ministry of the Environment

9

“Johkasou” as Decentralized Treatment System• Advanced domestic wastewater treatment system (tank) developed in Japan• Cost-effective in decentralized area
(Low initial investment cost)• Little topographic limitation,short installation time
• Invaluable contribution
to maintaining sufficient waterin small rivers• Less vulnerable to disasters

Johkasou(Anaerobic filter contact aeration type)
Ministry of the Environment

10Treatment Principles and Types of Johkasou• Designed for treating both black water and grey water• Wastewater are broken down biochemically by the catabolism of
microorganisms such as bacteria and metazoan organism

Ministry of the Environment

Structure and treatment principle of Johkasou

11Legislative Systems for Johkasou (Johkasou Law)
• Background of legislation◆

Water pollution and degradation of living environment caused byimproper construction and maintenance of Johkasou• Objective◆

To promote the appropriate treatment of domestic wastewater,
to maintain good water quality of public water bodies and a healthyliving environment, and to improve public health• Main contents of Johkasou Law
Notification of installation of Johkasou◆ Regulations on construction, installation, operation and maintenance,
desludging and examination◆ Qualification and licensing of technician and operators◆

Ministry of the Environment

12

Operation, Maintenance and Inspection of Johkasou

Inspection after construction

Ministry of the Environment

Annual inspection

13Comparison between sewerage treatment system and Johkasou
Sewerage treatment
systemJohkasouFunction

Wastewater treatment andPrevention of inundation

Wastewater treatment

ObjectTreating wastewatercollectively

Treating wastewater
Individually

Suitable area

Urban area

Area of scattered population

Administrator

Municipality

Individual or Municipality

Treatment plant : 15-70 years
Piping system : 50-120 years

main body : over 30 years
equipment : 7-15 years

Useful lifeof facility
Ministry of the Environment

14Plans of Prefectural Governments• For efficient construction of wastewater treatment facilities in each region,a construction plan for wastewater treatment facilities has been formulated
based on comparison of economic efficiency, etc.,
considering the characteristics of each wastewater treatment facility.
Cost per family(construction, operation & maintenance)

Equilibrium point

Individual treatment(Johkasou, etc.) is better
Ministry of the Environment

Individual treatment (Johkasou)

Mass treatment (Sewerage)

Population density

Mass treatment(sewerage, etc.) is better

15

Population Trends for domestic wastewater treatment

Self-management night soil area

Night soil
collection
Sewerage systems

Johkasou

Population Trends for night soil treatment and domestic wastewater treatment
Ministry of the Environment

16

Wastewater management – one of the 2nd phase WEPA’s theme

Target• To analyze each country’s situation, challenges, and policies on
domestic wastewater management, which is common issues for
improving water environment• To propose improvement strategies corresponding to challenges

What we do this year• Conduct questionnaire investigation on each country’s;
Current situation and challenges on domestic waste water◆ Representative points where water environment has been worsening◆ Good practices of domestic water treatment by local communities etc.
◆

Ministry of the Environment

17

WEPA Technology Database• Wastewater treatment facility
in operation for more than 3 years• 218 Data from 9 countries• Categorized byType of your treatment◆ Type of wastewater◆ Countries◆

Ministry of the Environment

18