As the pre-feasibility study(pre-FS) was adopted by MLIT*, the baseline survey of sewerage project focusing of urban flood control in HCMC was conducted by public-private sectors of Osaka City.

Using the pre-FS study adopted by MLIT*, we developed a model project for urban flood control to cope with the vulnerability of urban drainage systems in major cities in Vietnam and also examining the feasibility of applying a PPP method for implementation of an urban flood control project.

大阪市

Sewerage System Improvement（Vietnam）

● Program for Trenchless Pipeline Rehabilitation Technologyin Socialist Republic of Vietnam

The joint pilot project of sewer rehabilitation in HCMC will be implemented by Sekisui Chemical Co.,Ltd. and UITec as the JICA“Collaboration Program with the Private Sector for Disseminating Japanese Technologies”.

Sewer rehabilitation(image)

FY2011

Main Issues・Flood-prone land

～Flat low-lying area below sea level similar to Osaka City

・Insufficient capacity of discharge facilities～ Constructed during French colonial rule in the 1870s

Flooding in Ho Chi Minh City(HCMC) Canal water flows backward through street inlet

Meeting with Ho Chi Minh City government officials (July 2011)

● Study on Urban Flood Control in HCMC

● Feasibility study (FS) on urban flood control project using a Public-Private Partnership (PPP) method

FY2012

FY2013～FY2015

● Project for capacity improvement of urban drainage management in Ho Chi Minh City, Vietnam

Osaka City and Urban Infrastructure Technology Center Foundation (UITec) have started technical exchange on O&M of urban drainage facilities and has been improving safety management of O&M work in HCMC utilizing JICA’s Partnership Program.

Toxic gas Check(July 2013)

FY2014～FY2015

*Ministry of Land, Infrastructure, Transport and Tourism

・Insufficient capacity of discharge facilities～ Constructed during English colonial rule in the 1890s

・Lack of appropriate Operation and MaintenanceFY2012

“Formulation of the plan for sewerage system construction in Myanmar”was adopted as a Pre-Feasibility Study by MLIT, Osaka City and UITec have conducted the baseline survey in Yangon in order to grasp the current condition of stormwater drainage and sewage collection. From the findings of the survey, some solutions were offered by public-private sectors of Osaka City. Site survey of a sewage treatment plant

in Yangon City

FY2013

● Baseline survey of sewerage and drainage system in Yangon City

●Technical Exchange Programme on WastewaterManagement between Yangon City and Osaka City

As the Programme was adopted by CLAIR, Osaka City and UITec dispatched experts to Yangon and conducted a training in Japan for engineers of YCDC for the purpose of improvement of sewerage and drainage systems in Yangon City.

Discharge of domestic wastewater to stormwater canals in Yangon City

大阪市

Sewerage System Improvement（Myanmar）

● Capacity development of Sewer Pipes O&M and Rehabilitation Project in Yangon City

Using the JICA Partnership Program adopted by JICA in 2014, technology transfer of sewer O&M and rehabilitation is conducted by Osaka City collaborate with Sekisui Chemical Co., Ltd and UITec.

Pipe jacking construction site in Osaka CityFY2014~FY2016

Main Issues

Flooding in Yangon City

MLIT : Ministry of Land, Infrastructure, Transport and Tourism UITec : Urban Infrastructure Technology Center Foundation CLAIR : Council of Local Authorities for International Relations YCDC : Yangon City Development Committee

Sewer inspection in Yangon City

In the late 1960s, a period of high economic growth in Japan, the river water quality in Osaka City significantly deteriorated

due to domestic and industrial wastewater discharge. To solve this problem, sewerage system has been improved intensively

since then. Ten years later, Osaka City had almost finished installation of a modern sewerage system, earlier than any other

major cities in Japan. The river water quality was significantly improved and promenades were constructed along many rivers.

The City restored its water environment and it provides comfortable urban space where various events can be held.

On top of that, Osaka City developed unique technologies that make the best use of existing facilities, they make it possible

to conserve its aquatic environment at low cost.

0

20

40

60

80

100

0

10

20

30

40

50

60

1965 1975 1985 1995 2005

寝屋川

下水道人口普及率

(mg/L)

An

nu

al a

ve

rag

e B

OD

Percen

tage o

f sewered

po

pu

lation

(%)

Sewerage system was served rapidly

Water quality improvement

Sewerage coverage 

is approx.100%

From around 30% to around 90%

Neya river

Percentage of sewered 

population

■ Cutting Edge Technologies of Osaka City

Water Quality Control

Osaka City

Sewerage Technology in Osaka City

Primary settling tank

Reaction tank Digester tankFinal settling tank Advanced treatment

Thickener

Dehydrator Melting furnace

Sludge pipeline

Central sludge treatment facility

Melted slag(Granulated)

Existing step gateDigestion gas

Thermophilic / high concentration

digestion system

Sewage andstormwater

Sewage andstormwater

River

Inclined plate unit & water collection pipes

(patented)

Discharge after sedimentation

(2Qsh)

1Qsh

Primary sedimen-

tationtank

Return sludge

Wet weather

wastewater (3Qsh)

Activated sludge

treatment (3Qsh)

2Qsh

Aeration tank

Finalsedimen-

tationtank

Activated sludge treatment of stormwater

Stormwater storage pipe; (Heisei no Taiko-gesui)

Rapid filtration facility

First flush, initial rainwater containing high pollutant load,is temporarily stored in reservoirs or pipes and treated in sewage treatment facilities before discharging to rivers.

To further improve the water quality,advanced water treatment facilitiessuch as rapid sand filters are installed.

Advanced water treatment facility (Rapid sand filtration tank)

Inclined plates are installedin primary settling tanks toincrease the existing settling capability.

Filtration facility installed in existing primary settling tanks provides high rate treatment which saves settling space.

Treatment capacity of treatment in wet weather can be tripled by step feeding

Stormwater reservoir

Sand filtration

Final settling

Osaka City promotes energy saving and energy/resource generation by effectively collecting and using energy from resources

such as treated wastewater, sludge and exhaust heat. Treated wastewater is used for artificial river sources and other purposes.

The city also promotes effective use of sewerage facility roofs.

Primary settling tank Reaction tank Digester tankFinal settling tank Advanced treatment Thickener Dehydrator Melting furnace

Sludge pipeline

Central sludge treatment facility

Melted slag(Granulated)

Existing step gate Digestion gasThermophilic / highconcentrationdigestion system

Sewage andstormwater

Sewage and stormwater

River

Using the roofs of facilities, photovoltaic generation systems are installed to generate electric power, which covers part of the power used in sewage treatment plants.

Centralized sludge treatment

Sludge conveying pipenetwork

Maishima Sludge Center

In addition to centralized sludge treatment, OsakaCity promotes beneficial use of all sewage sludgeby converting the sludge into melted slag.

Energy recoveryBy employing thermophilic high-concentration digestion method, the amount of digestion gas is increased, while under the Private Finance Initiative (PFI) scheme, digestion gas is used for power generation.

Power generation using digestion gasPFI scheme

Photovoltaic generation

Photovoltaic generation

Reuse of wastewater

Treated wastewater supplied to Osaka

Castle moats

Treated wastewater used for artificial waterfront

While improving the quality of treated wastewater, Osaka City promotes the reuse of treated wastewater to create refreshing waterfront.

Beneficial recycling of resources

Phosphorus recovery

Phosphorus and other resources are recovered from sludge generated in the wastewater treatment process.

Under a project of Japan’s Ministry of Land, Infrastructure, Transport and Tourism, a verification test is conducted for efficient energy recovery .

Verification program on sewerage innovative technologies [Breakthrough by Dynamic Approach in Sewage High Technology (B-DASH) Project]

下 水 理 場

Digestion gas

Hot water

Consideration

Digestion gas isgenerated inthe process of

Sludge ferment

Slu

dg

e

Sludge generated inthe process of sewage

treatment

Electriccompanies

Electric powerstorage system

Digestiongas engine

Water heater

Exhaustheat

Electricpower

Power generation

Sludge Digestion tank

Water treatment facility

Sewage Treatment PlantPart of PFI improvement

and management

Power generationusing digestion gas

as fuel

Exhaust heat isutilized for heatingof digestion tank

[Water treatment system]

[Sludge treatment system]

Rawgarbage

Influx ofwaste-water

Power supply and control system

<Energy saving>

<Energy Creation>

□ Sludge Transportation Pipe network

Existing pipes

Planning pipes

Sludge TreatmentPlant

Jyuuhachijyo S.T.P

Imafuku S.T.P

Hanaten S.T.P

Hirano S.T.PTsumori S.T.P

Chishima S.T.P

Ichioka S.T.P

Konohana S.T.P

Ono S.T.PEbie S.T.P

Nakahama S.T.P

Suminoe S.T.P

Maishima

Sludge Center

Osaka City centrally manages the information of sewers in the city

(total length: 4,900 km, No. of manholes: 180,000) using the sewer

management system (AS map) to effectively manage and maintain

sewers, support rehabilitating aged sewers and respond to diversified

citizens’ needs.

■ Sewer management system

■ Asset management planning

Asset management planning is promoted to objectively manage and

evaluate the situation of a huge number of aging sewerage facilities, and

effectively and systematically repair and maintain them.

■ Sewer management system

■ Framework of asset management planning

Osaka City

Sewerage Technology in Osaka City

Initiatives

Clarification ofthe policy by

guidelines

Inspection and survey

Mid- to long-term planning

Short-term planning

<Systematic & effective asset managementplanning>

Mid- to long-term predictionthe damage of facilities byaccumulating inspection data

Asset management planning,considering the minimumlife-cycle cost

Equalization of rebuilding/repairProject costs, ImplementationPlanning considering theIntroduction of energy-savingfacilities

Information gathering oncurrent conditions, Earlydetection of abnormalitiesor damages

Securing of Mid- tolong-term safety and qualityservice

Securing of safety andquality service by planningshort-termfacility-managementsystem

<Maintenance of the sewage systemquqlity>

Beneficial use of resources/energy

Maintenance

■ Multiple Approaches for Flood Control

Most part of Osaka City area, except the Uemachi plateau, is low-lying and below sea level at high tide, thereby

vulnerable to heavy rains. In 90% of the city area, stormwater runoff cannot be gravity drained and has to be

pumped out. Thus, flooding has often occurred in these areas during heavy rain events.

As a fundamental flood control measure,

Osaka City constructed large trunk

sewers (used for water storage as well)

and pumping stations.

西 東

大阪湾生駒山

満潮位

Uemachi Plateau

<Flooding>

<Elevation Cross Sections in Osaka City>

In-situ pumping facilities were installed

for reducing localized flooding.

Making effective use of public space,

rainwater storage facilities were

constructed under parks.

River

Houses

Pumping in lowlands

Sewer management is centralized

under the sewer management system.

A rainfall radar was installed to get the real time data of rainfall in Osaka

City and its surrounding areas. Data are accessible by the Internet.

<Elevation difference in Osaka City >

High tide

sea level

Osaka Bay

West East

Mt. Ikoma

Osaka City

Flood Control Technology in Osaka City

Osaka City has taken various measures for flood control. As hard measures, fundamental measures such as

construction of large trunk sewers and pumping stations, and quick-impact measures such as installation of small

rainwater reservoirs at public space and manhole pumps have been taken. As soft measures, information

service using the rainfall radar system and centralized management of sewers have been implemented. These

integrated approaches including hard and soft measures had greatly contributed to the alleviation of food damage.