Ken Fukushi, Ph.D.
Associate Professor of Integrated Research System for
Sustainability Science
The University of Tokyo, Japanfukushi@ir3s.u-tokyo.ac.jp

1

y Economical development

 Income increase High energy consumption
 High material consumption
 Lifestyle change Diet change Etc.

 Urbanization

Waste Production
Water consumption
Air pollution and traffic jam

Traffic accident
 High-rise buildings
 Heavy traffic and highway
Energy shortage
 Dense population
Housing problems
 Good job opportunities and higher income
 Large energy, material, goods, and water demand Urban-rural problem2y Rapid development of urban area
 Increase commercial and domestic water usey Increase of population
 Increase domestic water use
y Change of lifestyle Increase domestic water use per capita (300 liter/p)y Inadequate wastewater treatment
 Deterioration of water environment
y Small amount of water recharge togroundwater Urban inundation and groundwater table decreasey Overuse of groundwater Groundwater table decrease and ground subsidencey Stealing water and illegal use of water3

Annual rainfall and water availability
Annual rainfall (mm year-1)

per capita (m3 year-1 capita-1)

CanadaNew ZealandSwedenAustralia
Indonesia
USAWORLD
Austria
Switzerland
The Philippines
JAPANFranceSpain
Italy
China
IranIndia
ThailandRomania
UK

Annual rainfall per capita
Available water resource
per capita
4

Modified from the source: Japan International Cooperate Agency

90

Urban population％

80
70
60
50

World
N. America
Asia

40
30
20
100

1950

1975

2003

2030

year
5

9Population, 100 million

87
65

China

432

China

India
India

1020032030

667Population with water supply/sewerage in Tokyo
14.0

Population (million)

12.0
10.0

95.9 %

Population with water supply
Population with sewerage
Total Population

98.0 %

8.0
6.0
4.0
2.00.0
1900

1910

1920

1930

1940

1950

1960

1970

1980

1990

Financial year
Figure created by Dr. S.Ishii, COE Project, Tokyo University
Created from the sources: Bureau of Waterworks, TMG; Keihin Office of River, MILT Japan; Bureau of General Affairs, TMG

2000
8Large share of treated water in rivers
Shishigebashi
bridge.
Purify 1000 literof wastewater
Kodairabashi bridge= approx 0.5 liter of crude
oil
50.6%
50.2%
= approx 0.2 kg of CO2
Shingashi riv.

Treating wastewater 2% of total
electricity demandof Japan
Sumidagawa
riv.

Ryogoku bridge

95.9%

Yanagibashi bridge

17.0%

Nakagawa riv.

71.0%

Tamagawa riv.

18.1%

Tamakawara bridge

35.3%

Kasaikobashi bridge

32.3%
Chofu intake gate
Taishibashi bridge
0 km 5 km 10 km

20 km
Tamagawa River, Picture source: Keihin office of river

Treated water (%)

9Source: Bureau of Sewerage, TMG

Rainwater and miscellaneous-use water reuse
National Sport Stadium

Tokyo Dome Stadium

Daily use: 20.9 m3 (70% of total)
Tank capacity: 1,000 m3

Daily use: 186.3 m3
Tank capacity: 1,000 m3For toilet flushing and cooling water

For toilet flushing only

Sinjuku sub-centre
Daily use: 2,740 m3 (30% of total)
Tank Capacity: 8,000 m3
For toilet flushing only
10Source: Bureau of Urban Development, TMG

Restoration of natural ecosystems and aquatic amenity

Nobidome yousui
Senkawa jyosui

Tamagawa jyosui

Dry
Dry upup
Picture source: Mitaka Education Centre
Picture source: Bureau of Sewerage, TMG

11

Ochanomizu station

Kandagawa riv.
Picture source: Tokyo Canal Project

Sumidagawa riv.
Picture source: Tokyo Canal Project

12Nihonbashi
Picture source: Tokyo Canal Project

“Developed countries apply energy-intensive technologies
to keep urban water environment clean, however, suchapproach may not be appropriate for sustainable water
environment management ” (modified from Wagner,
Ohgaki and Zehnder et al. in Ambio)y “Design, approval of the planning and the lay out of thepiping and sewer networks is time consuming and swallows
about 80% of the total investment costs”. (Peter Wilderer)y “Estimating the cost of worldwide implementation ofcentralized system, it become evident that the capacity of
global money market would not be sufficient to cover theneed for investment capital”. (Peter Wilderer)yyHowever, in old time, the centralized system is the only
choice since treatment technology was not available in asmall scale

Proposal of decentralize water management system

13y Advantages
 Easy for water reuse No need for pipeline to deliver wastewater Easy for groundwater recharge
 Relatively small investment for each unity Disadvantages
 Difficult to reuse water Need a small-footprint, high efficiency, easy
maintenance process Maintenance problem
 Big investment

14CityCountry

Coverage (%)

TokyoJapan

99.9

SendaiJapan

97.2

Bangalore

India

53%

KarachiPakistan

33%

Dhaka

Bangladesh

21%

ManilaPhilippines

11%
15

Decentralized water system:
example of single unit
Rain fall
Single house ~large
community
Water
supplyWater
purification

EnergyWastewater
Water reuse

Wastewater
treatment

Non-permeable layer (pavement, buildings etc)

Water recharge
Water use

Groundwater
MBR: Membrane bioreactor

16

Water Management Unit

• Utilizing sewer and watersupply systems• Use groundwater as a stock• Community can decidetreatment methodRiver

Lake17Water Management Unit

• Community-based
management• Utilizing natural system

Riverpond
Lake18

Decentralized water management system(ultimate status)
Rain••UrbanUrbanHeat
HeatControl
Control••Groundwater
Groundwaterutilization
utilization••Restoration
Restorationof
ofriverriver••Risk
Riskmanagement
management••Better
Betterstorm
stormwater
waterctrl
ctrl
Water
treatment

Heatmanagement

purification

River/lake

purification

Water system
地下水涵養recharge

recharge

recharge
groundwater

Urban water stock

groundwater

Groundwater flow analysis
1919

y Treating wastewater to produce extremely

clean water for groundwater rechargey Treating groundwater to produce
drinkable-quality watery Requirements for the technology
 Easy to maintain Low capital cost
 Safety of treated water

Membrane technology
20• Extremely highquality water• Easymaintenance andeasy mechanism• Potential to beeconomical• No need of hightechnology formodule
production(except RO)
Raw water

Purifiedwater

Raw water21

Microfiltration
MF

Ultrafiltration
UF

Nanofiltration
Membrane
NF
Reverse Osmosis
ROSize (μm)
Relative SizeofCommon
Materials

0.0001

0.001

0.01

Cl- ionNa+ionPesticide, Organic Material
Zn2+ionF- ionPb2+ ion
NO3-ion

0.1
Influenza Virus

Virus
Polio Virus

Sea Water Desalination

Less-fouling

Drinking Water

Algae, Mad

Coliform
Cryptosporidium

Hepatitis A Virus

Brackish Water Desalination

10

Vibrio Cholerae

Trihalomethane

Application

1Bacillus anthracis

Wastewater Treatment
Drinking Water

Drinking Water
22

Membrane Bioreactor (MBR) technology (keytechnology)
Conventional activated sludge system
Effluent
Prescreening

Sludge withdrawal

Biological tank Settling tank

Side stream MBR (1st generation)
Effluent
Membrane

Submerged MBR (2nd generation)

Kazuo Yamamoto (1989)

23

Hydrogen
carWater Reuse

H2 fuelcellH2ation
zilitU

Wastewater

MBRSludge

Can besmall scale

Supercriticalgasification

Nutrients

UseCan besmall scale24••Problem
Problem forfor MBR
MBR••Electricity
Electricity forfor operation
operationandand maintenancemaintenancewastewater

Load• Operation• Maintenance• Community
service• Commercial

MBR
MBR
Treated water(anaerobic) (aerobic)

reuse
Nutrients(N and P)

MBR with Microbial Fuel Cell (MFC)25

Outside ofthe region

Water stock

Water

Periurban areapoCr• Vegetable production and otherfarming activities• Leisure for urban people
Water stock

Natural beauty
WaterNutrient

GW Stock

Urban area

•Commercial activities
desalination

SeaEnergy
Production

Water stock

subsidy

Water stock

Safer products

Agricultural products$ for higher price products
Water stock

Energ

y26

y Decentralized water management system(combined with water reuse system)
potentially attractive for developing Asiancities
y Asian cities need to develop new type of
relationship with rural areay Development needs time. However, weexperience it much faster than westerncountries.
27Thank you
Special Thanks to:
Dr. Tran Thi Viet Nga
Dr. Ryo Honda
Dr. Kazuo Yamamoto
Sustainable Urban Regeneration Project
Toray Co. Ltd.

BOD 25 mg/l

Ken Fukushi
fukushi@ir3s.u-tokyo.ac.jp
28