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Sustainable Urban Region – water management for Asian cities
Ken Fukushi, Ph.D.Associate Professor of Transdisciplinary Initiative for Global
Sustainability (TIGS), Integrated Research System for Sustainability Science (IR3S), The University of Tokyo, Japan
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Urban water problems in developing regions
Rapid development of urban area– Increase commercial water use
Increase of population– Increase domestic water use
Change of lifestyle– Increase domestic water use per capita (300 liter/p)
Inadequate wastewater treatment– Deterioration of water environment
Small amount of water recharge to groundwater– Urban inundation and groundwater table decrease
Overuse of groundwater– Groundwater table decrease and ground subsidence
Stealing water and illegal use of water
3Modified from the source: Japan International Cooperate Agency
CanadaNew Zealand
SwedenAustraliaIndonesia
USAWORLDAustria
SwitzerlandThe Philippines
JAPANFranceSpainItaly
CHINAIranINDIA
ThailandRomania
UK
Annual rainfall (mm year-1) per capita (m3 year-1 capita-1)
Annual rainfall per capita
Available water resource per capita
Annual rainfall and water availability
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Increase of urban population
0
10
20
30
40
50
60
70
80
90
1950 1975 2003 2030
World
N. America
Asia
Urban population
％
year
5
Urban population increase
5
0
1
2
3
4
5
6
7
8
9
2003 2030
China
China
India
India
Pop
ulat
ion,
100
mill
ion
6
Water management in Tokyo
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0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
Population with water supply/sewerage in TokyoPo
pula
tion
(mill
ion)
Financial year
Total Population
Population with water supplyPopulation with sewerage
Figure created by Dr. S.Ishii, COE Project, Tokyo UniversityCreated from the sources: Bureau of Waterworks, TMG; Keihin Office of River, MILT Japan; Bureau of General Affairs, TMG
98.0 %95.9 %
8Tamagawa River, Picture source: Keihin office of river
Chofu intake gate
Yanagibashi bridge
Tamakawara bridge
Shingashi riv.
Shishigebashi bridge.
Tamagawa riv.
Kodairabashi bridge
Ryogoku bridge
Nakagawa riv.
Kasaikobashi bridge
Taishibashi bridge
71.0%
18.1%
32.3%
50.2%50.6%
95.9%
17.0%
35.3%
Source: Bureau of Sewerage, TMG
Sumidagawa riv.
Treated water (%)
Large share of treated water in rivers
0 km 5 km 10 km 20 km
Purify 1000 liter of wastewater= approx 0.5 liter of crude oil= approx 0.2 kg of CO2
Treating wastewater 2% of total electricity demand of Japan
9Sumidagawa riv.
Ochanomizu station
Nihonbashi
Kandagawa riv.
Picture source: Tokyo Canal Project
Picture source: Tokyo Canal Project
Picture source: Tokyo Canal Project
Water environment in TokyoWater environment in Tokyo
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Centralized water management system
“Developed countries apply energy-intensive technologies to keep urban water environment clean, however, such approach may not be appropriate for sustainable water environment management ”(modified from Wagner, Ohgaki and Zehnder et al. in Ambio)“Design, approval of the planning and the lay out of the piping and sewer networks is time consuming and swallows about 80% of the total investment costs”. (Peter Wilderer)“Estimating the cost of worldwide implementation of centralized system, it become evident that the capacity of global money market would not be sufficient to cover the need for investment capital”. (Peter Wilderer)
However, in old time, the centralized system is the only choice since treatment technology was not available in small scale
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Proposal of decentralize water management system
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Decentralized water management
Advantages – Need small investment for sewer pipeline
– Easy to reuse treated water
– Small investment for one unit
Disadvantages– Need effective maintenance system
– More energy consumption for operation
– Require sophisticated water/wastewater treatment processDevelop commercial maintenance industryTotal energy demand will be low
Need technology development
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Membrane process: hollow fiber
Raw waterRaw water
Purified water
•Production of extremely high quality water
•No need of high-tech for MF membrane fabrication
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Membrane Bioreactor (MBR) technology (key technology)
Conventional activated sludge system
Side stream MBR (1st generation)
Submerged MBR (2nd generation)
Biological tank Settling tank
Effluent
Sludge withdrawal
Membrane
Effluent
Prescreening
Professor Yamamoto, UT (1989)
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Membrane categories (Prepared by TORAY)
Membrane
Relative SizeofCommonMaterials
0.0001 0.001 0.01 0.1 1 10Size (μm)
Cl- ionNa+ion Pesticide, Organic Material
Zn2+ionF- ion
Pb2+ ionNO3
-ionTrihalomethane
Hepatitis A Virus
Polio VirusVirus
Influenza Virus Algae, Mad
Vibrio Cholerae
ColiformCryptosporidium
Bacillus anthracis
RO
NF
UFMF
Reverse Osmosis
Nanofiltration
MicrofiltrationUltrafiltration
Application
Sea Water Desalination
Less-fouling Drinking WaterDrinking Water
Wastewater TreatmentDrinking Water Brackish Water Desalination
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Groundwater
MBR*
Rain fall
EnergyWastewater
Water recharge
Membrane
Water use
Water supply
Decentralized water system: example of single unit
MBR: Membrane bioreactor
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Decentralized water management: urban area
River
Lake
Water Management Unit• Community-based management:
Outsourcing• Groundwater as water stock• Utilize existing water and
wastewater piping• Fast system recovery from
damage
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Decentralized water management: urban area
River
Lake
• Community-based management• Fast development and small
investment• Utilize more surface water for
discharge/recharge
Water Management Unit
19 19
Rain
地下水涵養
Groundwater flow analysis
recharge
Water system
purification
Heat management
Urban water stock
Water treatment purification
rechargerecharge
groundwater groundwater
River/lake
Decentralized water management system(ultimate status)
•Urban Hear Control•Groundwater utilization•Restoration of river•Risk management
•Urban Hear Control•Groundwater utilization•Restoration of river•Risk management
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Other potential for wastewater: zero-energy wastewater treatment
MBR(anaerobic)
MBR (aerobic)
MBR with Microbial Fuel CellMBR with Microbial Fuel Cell
wastewater Treated water
Load
Nutrients (N and P)
•Operation•Maintenance•Community service•Commercial
reuse
•Problem for MBR•Electricity for operation and maintenance
•Problem for MBR•Electricity for operation and maintenance
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Future Asian cities
Sea
Periurban area• Vegetable production and other
farming activities• Leisure for urban people
WaterNutrient
Agricultural products
Water
Urban area•Commercial activities
subsidy
$ for higher price products
Natural beauty
Safer products
Crop
Energy
desalination
Water stock
Water stock
Water stock
Water stock
Water stock
EnergyProduction
GW Stock
