Strategy on Wastewater Control in Japan for 21stCentury
TANAKA Shuji 1, NASU Motoi 2
1

Director, Water Quality Control Department, National Institute for Land andInfrastructure Management, Ministry of Land, Infrastructure and Transport

2

Director for Sewerage Engineering and Development, Sewerage Planning
Division, Sewerage and Wastewater Management Department, City and Regional
Development Bureau, Ministry of Land Infrastructure and Transport

Abstract: When we stepped into the 21st century, we noticed so many changes invarious fields, such as meteorological change in global scale, soaring price of
crude oil, frequent draughts and floods, overt heat-island phenomena in big city
areas, falling birthrate and rapidly aging population. These changes are nottemporary mutations, but are transformations based on a long-term trend that wecannot ignore for planning and re-visioning of the future state of the wastewater
systems. Starting from these understanding of present state of circumstances, newconcept for the role of wastewater system is formed as a national strategy to be
key infrastructure for recycling society, namely “The Road toward Recycling
Society.” This paper describes the new concept of The Road toward Recycling
Society along with its implementing policy.
Keywords: Recycle, theimprovement of systems

21stcentury,

policyforwastewater

system,Introduction
When we have perspectives of the 21st century, we can predict great changes inJapan that will emerge in many fields. We must change our living systems
preparing for the coming future. Our systems consist of many sub-systems.
Wastewater system is one of them, but important one to keep our society in healthy
and comfortable one. This means that we need to have a new concept adapting oursociety to future situations. For setting the new concept and policy both of thewastewater systems and the wastewater works, a special committee was convened
1

adress: Asahi 1, Tsukuba, Ibaraki, 305-0804 Japane-mail: tanaka-s92ta@nilim.go.jp
2adress: 2-1-3 Kasumigaseki, Chiyoda-ku, Tokyo, 100-8918 Japane-mail: nasu-m2ij@mlit.go.jp- 57 -

and carried out intense discussions for about one year, and announced theirconclusion in a report titled as Wastewater System Vision 2100. The subtitle of thisreport is “From Wastewater System to The Road toward Recycling Society as
100-years strategy”. This paper describes about this new strategy and new conceptof The Road toward Recycling Society.
A new concept for wastewater system adapting to the 21st century
Among the various future changes, some of the serious ones that we will face inthe latter part of the 21st century may be the climate changes that will be causedby greenhouse-gas effect and the shortage of natural resources such as fossil oil
and natural gas. These changes will be caused as the consequence of our lifestylein the late 20th century of mass production and thus mass waste-production. In
these several years we already suffered from abnormal climate that caused terrificflooding, unusual hot summers and abnormally heavy snowfalls. Anotherprecursor of the future problem is the historically high oil price of these days.
When these difficulties become extreme situations, our lives itself will bethreatened by the problems. In view of this, we must adapt our society tosustainable one for future prosperity.
Other problems that we will also face in relatively near future in Japan are social
problems that will be caused by decrease of population. Although the diminutionof the population was predicted and well recognized in relatively long ago, it wasa great shock for Japan in last year that periodic census showed actual reduction of
the population. This reduction is due to the small number of birth rate of thesedays that is less than the death rate. On the other hand the life expectancy in Japanis high number. Consequence of these conditions introduces aging society andstructural changes in industrial fields and economic aspects. In the aging society
government will have limited resources for affording new infrastructure than our
generations, and thereby we need to prepare for the future in early stages.
Along with the changes in the future of the natural environment and society, we
are also questioned about the direction of future society. In these respects,
wastewater system also must change for the establishment of bright future. We
need to have a clear image of wastewater systems as new functions and new rolesin the 21st Century as a key infrastructure for better world, thinking out of
conventional images of the systems. For these view points, the vision for 21st
century of the systems should work to bring out three goals: beautiful environment,- 58 -

safe community and vigorous society. To realize these three goals, how ourwastewater systems contribute to new era becomes crucial point. Contemplatingthese conditions, the new concept as the 21st century of wastewater systems has
been emerged as “The Road toward Recycling Society” for the new strategy of thecentral government.

Figure 1. Schematic image of wastewater system’s role in the 21st century society
Wastewater system is a key infrastructure to sustain limited resource society.
Besides above-mentioned future problems, we have already some problems
straggling to solve in our working fields. Some of them are categorized in water
problems and others are facility management. One of the examples of water
problem is the quick run-off of storm water and dried up in the dry seasons inwaterways. These cause frequent flooding and less amenity environments. Thesephenomena are caused partly because of the reduction of impermeable area in ourcommunities. Another water problem is instability of water resources, such as big
cities cannot secure their water resources within their water basins. These are notsustainable situations in terms of water resources. A typical example of facility
managing problem is increasing aging facilities. These cause not only highdemand of rehabilitation works and thereby high requirement of budget, but also
increment of road corruptions caused by corroded sewers. The new policy is also

- 59 -

accounting these present problems into them.
What is The Road toward Recycling Society?
The term of The Road toward Recycling Society implies not only the venous
system but also the arterial system including heart, which works as key organs forcirculation of necessary materials and waste transportations of humans; in anotherword The Road toward Recycling Society suggest that the wastewater systems
become key facilities for hydrologic circulations and resource cycles. This concept
aims to change the 20th-century-type wastewater systems for new ones, and alsoseeks for new functions and images of the systems for 21st century. Morespecifically from the viewpoint of the healthy circulation of resources, discussion
in the committee about the systems extended to basic question about what iswastewater system and what kind of substances we should collect with the systems
and should not collect or how to recover and reuse from the collected substances,and how to create healthy recycling systems in our society. Based on these
rethinking works, following three key sub-concepts were presented to achieve themain image or metaphor of The Road toward Recycling Society:- Creation of New Water Passage,- Creation of New Resource Passage and- Revitalization of the Systems.
The first sub-concept, Creation of new water Passage, intends to create newwater-networks and passages for exploiting manifold function of water fromwastewater work filed. The second sub-concept, Creation of new resource Passage,plans on active working to recover resources, such as bio-solid or nutrients, andfollowed to supply recovered resources. This sub-concept also includes exploiting
land site of wastewater work to create new energy, ---solar power, wind turbine,and micro-hydro-power generation--- to depart from dependence on oil. The third
sub-concept, Revitalization of the Systems, is different from previous two concepts
in supporting them, but has more active meaning to refresh existing facility and tomeet the social requirements for the wastewater works.

- 60 -

Figure 2. Relation between main concept and three sub-concepts

The Creation of new water Passage and its policy development
The Creation of new water passage implies to recover health water cycle in basin
area by improving wastewater systems. This will be attained with evolving
following three core-ideas:-Recycle and reuse stored rainwater, purified wastewater and incoming groundwater into the systems thoroughly,-Optimize facility location based on aiming on water reuse and-Redesign facility structure fitting for water reusing.
Healthy water cycle will be realized through encouraging infiltration of storm
water to the ground along with reusing of stored storm-water andtreated-wastewater. Storm-water infiltration can be realized with storm -water
system designing based on infiltration first not draining first. Along with
infiltration first policy, introduction of storm-water storage facilities to systems
stimulate increment of reusing of water. Direct reuse of treated wastewater also
should be inspired with advanced treatment.

- 61 -

Storm-water utilization and treated-wastewater recycle may require deferent
configuration and location of the facilities from existing ones. Althoughconventional decision way for the location and capacity of treatment plant is basedon how effectively we can collect wastewater to a plant, the location and capacity
should be decided according to the demand of water. In this new way, the locationand capacity may be greatly different from existing plants. Same idea also should
be applied to storm water systems. The viewpoint of how effectively we can makerecycling systems facilitates reorganization and rehabilitation of water networks.
The structure of the storm water systems also may be changed greatly when we
introduce the new concept into designing of detail structures. For example, storm
water drains becomes open channels instead of pipe systems along with applying
percolating structure and ecologically friendly configurations, in another terms
near natural systems and nature friendly systems.
The Passage for Resources and its policy development
The Passage for Resources aims resource recovery through wastewater works andthus supply recovered resources to communities. Introducing this scheme aims lessrelease of global worming gas from the wastewater systems by promoting energy
saving in the systems and boosting for using greenhouse-gas-free energy to local
communities such as biomass energy.
This will be realized following three ideas:-Realize self-supporting in energy use for treatment systems,-Become a top runner of new-energy application by wastewater works and-Supply energy & resources actively to local communities from wastewater
works.
These three ideas need to be accounted in more specifically. The first idea,
realization of self-supporting in energy usage for treatment systems, aims inpromotion of energy saving, producing new energy in the systems, and trying
independence from outer energy supply for facility operations. The second idea,
becoming top runner for new energy, proposes wastewater works to be a top
runner of new-energy user and producer. The third idea, supplying energy &resources that are recovered from wastewater woks to local community, intend to
become energy and resource center through wastewater works.

- 62 -

The Revitalization of the Systems and its policy development
The Revitalization of the Systems proposes effective maintenance of existing
facilities and improvement of the systems to support the two other sub-concepts,
Creation of new water Passage and Creation of new resource Passage. Basic
policies for realizing this concept are extended into following three ideas:-Transform maintenance policy from reactive to preventive type,-Improve facilities to meet social demands including multi purpose usages and-Integrate new facility constructions and maintenance works into asset
management.
For these purposes following three working category is considered in actual fields:
works for safety, works for exploiting of facilities and works for improvement offunctions. The works for safety suggest proactive measures for accident due topoor maintenance works such as road corruptions caused by corroded pipes,
anti-earthquake measures, and contribution to local community for providing portof distress. The works for exploiting of facilities means promotion of multipurpose
usage of existing facilities. The works for improvement of functions implies not
only simply improving of facilities but also active management in accordance withoverall review of system plans including to meet new concept for Road toward
Recycling Society.
Conclusion
The 21st century is an era that we will face many difficulties in terms of shortageof resources and climate changes. To cope with theses situations we need newconcept and policy for our wastewater systems to abate these impacts. As the newconcept for 21st century wastewater systems, The Road toward Recycling Society
is proposed through one-year committee discussions. The new concept is dividend
into three sub-concepts that are Passage of Water, Passage for Resources andRevitalization of the Systems. Each sub-concept contains specific polices topromote actual works. We have just started evolving wastewater works based on
this new concept, thereby the actual promotion is small at this moment but have agreat expectation in a future to be a key infrastructure of recycling society.
References
Ministry of Land Infrastructure and Transport: Report on Wastewater System
Vision 2100; The Road toward Recycling Society. September 2005.

- 63 -

Strategy on Wastewater Control
in Japan for 21st Century
Overview of Sewage Works in Japan

Motoi NASU
Director for Sewerage Engineering and Development
Sewerage Planning Division
Sewerage and Wastewater Management Department
City and Regional Development Bureau
Ministry of Land , Infrastructure and Transport

1

Overview of Japan

Dissemination of sewerage

・Japan is an archipelago stretching over a great distance from north to south with a vast rangeof climatic zones
・About 80% of the territory is either mountain or forested land・Sewage work in Japan was developed rapidly since 1960’s
・Regional divide is one of the distinguishing characteristics of sewage works in Japan・Narrowing the gap of regional divide remains a major challenge

Percentage of sewered
population by city size

Percentage of sewered
population

Tsukuba
Tokyo
Tokyo Bay

Kyoto
Kobe
Ise Bay

FukuokaOsaka
Bay Osaka

Population(million)

Yokohama

Area(billion m2)

USA

Japan

281

127

9,628

378

100

94

121 123

125 126 126 126 126 126 127 127 127 127

54%
44%

36%

60

67

30%

6%

56%

58%

60%

62% 64%

68%
65% 67%

70%
60%

88
85 86
80 83
75 78
71 73

43

40%
30%

Sewered population

20%

35

8%

50%

26

10%

16

0

5

0%

8

61 65 70 75 80 85 90 95 97 98 99 00 01 02 03 04 05

80.8%

Average：69.3%
76.8%

67.7%
53.8%
39.3%

Over 1,000

500～
1,000

100
～
300

300
～
500

50
～
100

Less than 50

Total
number ofcities

11

15

46

189

282

1,279

Total
population(million)

26.19

10.76

17.79

30.45

19.62

22.25

Seweredpopulation(million)

25.76

8.69

13.66

20.62

10.56

8.74

Sewered ratio is only 39%
among the cities with population
less than 50 thousand

3

Recovery against Seismic Damages

・Recently, heavy rain that exceeds over the presumption of sewerage plan occurs frequently
in urban area of Japan, causing the inundation and death accidents in underground facilities
・In order to protect lives and urban system, various measures are taken in sewerage facilities
such as publication of hazardous maps, management of retention facilities, remote control ofsewerage facilities, etc
Damages by inundationin urban area

Population(thousand)98.3%

24 million
people are
not sewered

Increasing
constantly since
1960’sPrevention of inundation

・Since there is a lot of active fault located in Japan, the potential for large-scale earthquake
may occur at any time・For the sewerage facilities built before 1998, more than 80% is not earthquake resistant・Measures to secure the minimum function of sewerage at the incident of large-scale
earthquake is promoted urgently and intensively

Increase in occurrenceof heavy rain
Time/year(回 ／ 年 ）Damages to sewage facilities
at Niigata-Chuetsu earthquake in 2004

2004年

４７０
470 回（過去最高）(worst)500

Leakage of wastewater

400

Examples of measures
・Improvement of resistance to earthquake
in sewer pipes especially under the mainroads
・Improvement of resistance to earthquakein pumping station and STP

300
200
1976～1985

100

Water-covered roads(Tokyo, 2004)

69%

54

23%

40

90%
80%

98

Percentage ofsewered population

80

20

2

Stormwater flowing toUnderground facilities(Fukuoka, 2003)

117

16%

Naha

Kagawa112
104

Population (million)

Niigata(Chuetsu)

Total population

120

Percentage (%)

140

Comparison between
USA and Japan

100%
90%
80%
70%
60%
50%
40%
30%
20%
10%

1986～1995

平均２０９回

1996～2005

平均２３４回

Ave.209

Protrusion of manhole

平均２８８回

Ave.234

Ave.288

0
1976

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

2002

・Preparation of toilet directly connected tomanhole2004

・Development of pipe network to connect
each STP

4

5

Control of CSO

Promotion of advanced treatment
・As a consequence of eutrophication, red tide and blue tide still occurs frequently in lakes
which are sources of water supply and three big bays
・For example, advanced treatment ratio remains very low level, although the majority of influxof nitrogen and phosphorus comes from sewerage
・Therefore, intensive promotion of advanced treatment is mandatory especially in three bigbays, enclosed water bodies including lakes, and sources of water supply

・In CSO, untreated wastewater is discharged during rain, resulting in contamination of
public water bodies
・Enforcement ordinance in Sewerage Law was revised to promote the measures tocontrol CSO by 2014 in principle
Examples of measures
Retention facility

Achievement ratio ofwater quality standard
100
90
80
70
60
50
40
30
20
10
0

Implementation ofadvanced treatment
・14% of total population implemented
advanced treatment

河川（BOD）
Lakes
(BOD)
Three
big bays (COD)
三大湾（COD）
Lakes
(COD)
湖沼（COD）

Three big bays andlakes are not improving
49 51 53 55 57 59 61 63 2

4

6Store the stormwater
during rain, and treat it insunny days

Implementation of measures
to control CSO
・191 cities implemented CSO
measures out of total sewered
cities(1,899 cities)

・Advanced treatment ration in three bigbays are as follows:
Tokyo Bay
3.6%
Ise Bay
17.3%
Osaka Bay
14.1%

マンホール

流入管渠

Screen

搬入出口

ゴミを除去

ろ過スクリーン・20% of total population
implemented CSO measures

遮集管渠

Remove garbage
in stormwater

処理場へ
雨水吐き室
放流管渠

河川等へ

Infiltration
facility

8 10 12 14 16

Reduce stormwatercollected in sewerage

Fiscal year6

- 64 -

7

Utilization of resources
・Amount of water treated in sewerage is about 14 billion m3, and it can be used as importantsource of water for landscape use, flush toilets, etc (reclaimed water: 0.19 billion m3 (1.4%))
・Increasing amount of sewage sludge is utilized as fertilizer and construction materials
conventionally (recycled sewage sludge: 2.17 million DS-t (67%)).
・ Recently, focusing on the characteristics of carbon neutrality, conversion to bio-gas andsludge fuel is promoted as countermeasure to global warming

The Road toward Recycling Society
Utilization of advanced
treated wastewater forlandscape use in
Tadotsu, Kagawa
Prefecture

Bio-gas used as fuelfor CNG vehicles in
Kobe

Energy use as bio-gas
in Yokohama

89

New concept for wastewater system

The Road toward Recycling Society

・Climate change and the shortage of natural resources will be the serious challenge in 21st
century・Japan is also facing the decrease of population and related social problems
・Under these conditions, new concept for the role of wastewater system “The Road toward
Recycling Society” was formed in “Wastewater System Vision 2100” established in Sept. 2005

・The concept aims to change the 20th century type wastewater system to 21st century type
・It consist of three sub-concepts:
Creation of new water passage … water-networks to exploit manifold function of water
Creation of new resource passage … recover and supply resources such as bio-solid
Revitalization of the systems … refresh existing facilities to meet social requirements

Schematic image of wastewater system’s role in the 21st century society

Relation between main concept and three sub-concepts

1011

Creation of new water passage

Creation of new resource passage

・New water passage implies to recover health water cycle in basin area
・Three goals to be achieved:-Recycle and reuse stored rainwater, purified wastewater and incoming ground water into thesystems thoroughly-Optimize facility location based on aiming on water reuse-Redesign facility structure fitting for water reusing

・New resource passage aims recovery through wastewater works and supply to communities
・Three goals to be achieved:-Realize self-supporting in energy use for treatment systems-Become a top runner of new-energy application by wastewater works-Supply energy & resources actively to local communities from wastewater works

Self-supporting in energy in STP

Supply of water for fire-fighting
using storm water retention facility

Resource collection, regenerationand supply system
エネルギー供給
Energy supply

下 水 STP処 理 場《 その他 》
小水力発電、NaS 電池導入

Creation of favorable water
environment in Osaka

Multipurpose
water retention
network

等

Electricity
電 力

Sewage,garbage
汚水・生ゴミバイオガス
Biogas

資源のみち

Network for
infrastructure

汚泥（消化ガス）利用

太陽光・風力利用
Solar
power, windelectricity
5,396kwh/日

Digestion gas
6,600kwh/日

生ゴミ・剪定ゴミ利用
Garbage, scrap

汚泥燃料化
Sludgefuelwood
4,620kwh/日

Scrap
wood
剪定廃材
処理場電力消費量
19,035kwh/日

水・資源再生センター
STP

Electricity
火力発電

Resource
supply
資源供給

総発電量

Fertilizer
肥料

Energy16,616kwh/日
use in STP

Storage space in case of
emergency

Storage of water for
fire-fighting

Retention of waterin heavy rain

約Self
90％
に相当
supply● 新資源回収システム開発
Manure
家畜排泄物

リン等のPhosphorus

・下水処理システムと一体的なシステム

12

資源回収

13

Revitalization of the systems
・Revitalization proposes effective maintenance of facilities and improvement of the systems to
support the two other sub-concepts
・Three goals to be achieved:-Transform maintenance policy from reactive to preventive type
-Improve facilities to meet social demands including multi purpose usages-Integrate new facility constructions and maintenance works into asset management
Utilization of optical fibers in sewer pipes
for development of information exchange

Asset management of seweragefacility through IT
人工衛星

管理局

降雨レーダー

ＧＩＳ

Weather bulletin

Location

PR of events

Administrative service

Utilization of opticalfibers in sewer pipes
Inundation information

自動計測機器GPS

出張所
Pumpingfacility
ポンプ場
computerization
電子化

ＯＳソフト

資産管理

Traffic condition

Management
財務会計
data of sewerage
施設台帳
facilities

マンホール
Manhole光ファイバー
Opticalfiber
通信網

遠方監視システム

維持管理データ

ＩＣタグ

Management
information

Shopping

Sewer
pipes
下水管渠

自動計測機器光ファイバー

Optical
通信網fiber
インターネット
Web site
ホームページ

下水処理場
STP

Thank you for your attention!!

Residents
住民

14- 65 -

15