Corporate Outline

27,123 million yen (FY 2022)

Established on

August 1, 1984

No. of employees

969 (as of April 1, 2023)

Stockholders

Tokyo Metropolitan
Government

Tokyo Metro Marunouchi Line

Tokyo Sewerage
Facility Association
Sompo Japan Insurance Inc.

Mizuho Bank, Ltd.
Mizuho Trust ＆ Banking
Co., Ltd.
MUFG Bank, Ltd.
Asahi Mutual Life
Insurance Co.
Tokio Marine & Nichido Fire
Insurance Co., Ltd.

Marunouchi
Entrance

North
EntranceTo
Yurakucho

Marunouchi
Oazo

JRTokyo Station
Yaesu Entrance

Sapia Tower
Nihonbashi
Entrance

Meiji Yasuda Life
Insurance Company

Otemachi Station

Daimaru
Department Store
Sotobori Street

B7

Bus Terminal
Marunouchi
Trust Tower
N Building

New
Otemachi
Building

Otemachi Station
B7 Exit

Tokiwabashi
Tower

NTT Data
Otemachi
Building

Zenigamecho
Bldg.

ss w ay

Sales amountn Expre100 million yen

politahttps://www.tgs-sw.co.jp/

Capital

M etro

URL

Toky
o

+81-3-3241-0711 (Main number)

e

Phone

Hanzomon Lin

Zenigamecho Bldg., Otemachi 2-6-3, Chiyoda-ku,
Tokyo 100-0004 JAPANTokyo Metro

Headquarters

Otemachi Station

Mamoru Kamiyama

Tokyo Metro Tozai Line

Tokyo Metropolitan Sewerage Service Corporation

President

Eitai Street

Corporate name

To Kanda

Edo Street

Entrance

Corporate Profile

B2

Mitsukoshi-mae
Station B2 Exit

Mitsukoshi-mae
Station

Link tothe website
We support the Sustainable Development Goals (SDGs).

Acquisition of ISO 9001 Certiﬁcation

Scope of Registration:
Operation and maintenance of sewage sludge
treatment facilities (condensation, digestion,
dewatering, and incineration process)Applicable Oﬃces:
Miyagi Sludge Oﬃce, Shingashi Sludge Oﬃce, MorigasakiOﬃce, Kasai Sludge Oﬃce, Eastern Region Sludge Oﬃce,
Southern Region Sludge Oﬃce

Published in July 2024
6-002

Message from the President

Corporate Philosophy

Using the power of sewerage tomake a sustainable society the “new normal”

Tokyo Metropolitan Sewerage Service Corporation (TGS: Tokyo Gesuido Service)

was established in 1984 to pursue eﬃciency and economy, while continuing toserve the public welfare, by integrating and utilizing the funding and technologicalcapabilities of the Tokyo Metropolitan Government and private companies.

Since that time, we have worked to maintain and improve sewerage service as amember of the Tokyo Metropolitan Government group through integrated

business operation with the Bureau of Sewerage, Tokyo Metropolitan Government.
In April of 2022, TGS was entrusted with the overall management of the Ochiai

sewage treatment plant. As a result, the projects that we started when TGS

was established, which centered on sludge treatment, have now grown to
include comprehensive responsibility from upstream services related to
sewers to downstream, encompassing work from maintenance managementand design/construction management of sewer pipes to the operation andmaintenance management of sewage treatment plant, pumping stations andsludge treatment facilities.

Utilizing our accumulated advanced technologies, know-how and humanPresident andRepresentative Director

Mamoru Kamiyama

resources, we have also become a driving force for the sewerage industry through eﬀorts which are not limited to
the Tokyo Metropolitan area, but also include other parts of Japan as well as overseas countries, for example, humanresources development and transmission of technologies to the next generation, support in time of disasters andinternational expansion of Tokyo-originated sewerage technologies.

In the future, we will contribute to realizing a sustainable society by supporting safe, pleasant life and the growth of

the Tokyo Metropolitan area through the concerted eﬀorts of all our employees, to ensure that sewers function 24
hours a day, 365 days a year, utilizing the sewerage business operation capabilities we have developed to date.

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Toward the realization of a sustainable society

01 Supporting safe and pleasant life・
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02 Supporting the development of Metropolitan Tokyo・
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03 Creating a good water environment・
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04 Eﬀective utilization of resources and energy・
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05 Responding to issues at the site in Japan and other countries 13
A foundation of human resources ‒ People are the treasure・
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2

Diverse roles of sewerage

Division of roles of the Bureau of Sewerage and TGS

Sewerage has 3 basic roles in supporting life and the urban cities: “Treating sewage to ensure a clean, healthy environment in the city,”“Protecting the city from ﬂoods” and “Protecting the water environment of oceans and rivers.” It also has diverse roles in recycling
sewage as a resource and eﬀectively utilizing its energy, including “Recycling sludge as a resource,” “Reusing treated water,” “Use ofdigestion gas and heat,” etc.

Designing and Planning

Construction

Bureau of Sewerage (Tokyo 23 Wards)

Drafting of sewerage plans,construction of new facilities and reconstruction of
aging facilities.

Management planning
Public relations/public hearings
Human resources
Asset management
Contracts

TGS

Sewerage systems consist mainly of 4 facilities: Sewer pipes, pumping stations, sewage treatment plants and the sludge plants (sludge treatment facilities).
TGS performs operation, planned inspections, cleaning, repairs, and other activities to ensure that all of these facilities can function as an integrated system
24 hours a day, 365 days a year.

Sewer pipes

Pumping stations

Sewage treatment plants

13 locations (Sewage treatment facilities)

5 locations (sludge treatment facilities)

Wastewater (sewage) discharged fromhomes and factories and rainwater fromroads is collected in “sewer pipes.”“Pumping stations” are provided in places
where sewer pipes are deep undergroundin order to pump up sewage.
During rainfall, the rainwater is drained oﬀ
to protect the city from ﬂooding.

“Sewage treatment plants” purify sewage
through a multi-stage process and return
the puriﬁed water to rivers or the ocean.

The waste accumulated in the sewage
treatment process at “sewage treatment
plants” is collected as sewage sludge andtreated by incineration at “sludge plants(sludge treatment facilities).”Planning of construction
and improvement projects

82 locations

Sludge plants

Design and supervision offacility construction/
improvement projects etc.

Basic plans for facility
maintenance, etc.

Direction of sewage ﬂow

Technology development,
etc.

Design, supervision, etc. of repair work
Operation & maintenance (O&M), maintenance management (some facilities) and water quality control

Research and development of
new technologies
Expansion to other parts ofJapan/other countries
Training for other organizations,etc.

3Operation & MaintenanceApprox. 16,100km

Establishment ofregulations, etc.

Correct functioning of the sewerage system contributes to protecting the day-to-day lives of Tokyo residents and preserving theenvironment, including rivers and oceans.
Based on its sharing roles with the Bureau of Sewerage (Tokyo 23 wards), Tokyo Metropolitan Government, the Tokyo Metropolitan
Sewerage Service Corporation (TGS) is responsible for front-line work at the actual site in each of the stages of “Designing and planning,”“Construction” and “Operation and maintenance,” and is working to ensure the functioning of the sewerage system.

Investigation ofreconstruction projects
Sewer pipe design estimation
Supervision ofsewer pipe construction

Sewer maintenance service(patrol and inspection, investigation, supervision of
repair construction work, etc.)

Call center service(emergency contact during nighttime/holidays)

Inspection and conﬁrmation ofprivate sewers in residential areas

O&M of sewage treatment plants/
pumping stations (some facilities), maintenance management,water quality control (some facilities)

O&M of sludge treatment facilities(operation management, maintenance management)

Sludge recycling/utilization ofrenewable energy

Water quality testing/investigation

Recycling of construction surplus soil

Supply of recycled water

Sewerage mapping and information system service

Optical ﬁber network facilities management service

4History of TGSSupporting
safe andpleasant life

Supporting
the growth ofMetropolitan
Tokyo

Creatinga good water
environment

TGS was established as an organization that performs precise operation and maintenance of Tokyoʼs vast system of sewerage facilities.
Since then, we have steadily operated, developed and expanded our businesses in response to changes in the social environment surrounding the sewerage business, the expectations of society, and other needs.

1984

1985

1988

1998

2000

2005

Establishment of TGS

Sewerage call center
service

Construction surplus
soil improvement
service

Drainage equipment
workshop service

Sewerage mappingand information
system/maintenancemanagement service

International
promotion service● 1984.8.1● 1985~● 1984〜

Parking lot
management service

1999● 1984〜

Drainage equipmentrelated service● Trunk sewer survey● 1984〜

Investigation service● 1984〜

Utilizing
resources andenergyResponding
to issuesat actual sites
in Japan andother countries● 1998~● 1988~Sludge treatment
service● 1999~● Restoration ofclean waterin Meguro River
using recycled
water● 1984〜

Recycled water
service● 2000~2004● 2004~● 2005~2007

Human resources
development/
technology succession● 2008~Sewage treatment
maintenanceservice● 2008~Construction supervision
support service
Estimation systemservice

Sewer maintenanceservice

Sewer design
estimation service● 2004~● 2007~● 2008~

2010

2019

2022

Visitor guiding service
at sewerage facility

TGS entrusted withall sewer line
operation andmaintenance services
in the 23 wardsof Tokyo

Ochiai OﬃceComprehensive
management of
sewage treatment
facilities● 2010~● 2010~15

Disasterrecovery support
for Urayasu Cityand Katori City2012
● 2012~● 2019~2020● 2022~● 2022~● 2020~Registrationas construction
consultant

Head Oﬃce
relocated

Sludge recycling service

Sludge recycling
service

Optical ﬁber network
facilities management
service● 1984〜

Technology
development service

Water quality testing
service

Operation of sewerage
equipment operation &maintenance system
Carbonizing furnace

1994

2004

Transition of sales volume
Transition of number of employees¥ 200 million

2008● 2007~● 1984〜1984● 2008~2014¥ 21.7 billion

897persons¥ 9.8 billion
211persons2023¥ 29billion (estimated)

969persons¥ 7.5 billion
273 persons

24 persons

5

1984

1994

2004

2014

2023

6

Main Award-Winning Technologies

TGS is actively engaged in technology development to solve the problems facing the Tokyo sewerage system based on ideas proposed by workers at frontline sites.
The developed technologies have been adopted not only in the Tokyo Metropolitan area, but also in other parts of Japan and overseas, and have earned a high evaluation,
including winning many prestigious awards, etc.

① Earthquake-resisting construction method(ﬂoatless method)（●）⑧ Anaerobic and simultaneous nitriﬁcationdenitriﬁcation treatment method（●●）

Technology for preventing ﬂoating of manholes causedby ground liquefaction in earthquakes

Method that combines nitrogen treatment and the anaerobic methodby simultaneously performing digestion and denitriﬁcation in thesame tank● FY 2012 Japan Society of Civil Engineers Innovative Technique Award

Technologies
recognized for
Pipeline facility information system with diverse functions enabling eﬀective social contribution

Technologies
recognized forinvention/development② Total Information System for Sewerage Management(Total-ISM)（●）
coupled use of the sewer pipe inner surface expansion plan drawing system,
sewer pipe design CAD system and other tools● FY 2014 Nikkei Global Environmental Technology Award,
Technologies
Prize for Excellence
recognized for● FY 2016 Japan Sewage Works Association Excellent Paper Award
FY 2016 Society of Environmental Instrumentation, Control and Automation
employee achievements ● Encouragement
Award● FY 2020 Excellent Environmental Equipment Award, Ministry of Economy,
Trade and Industry (METI) Ministerʼs Award● FY 2017 Ministry of Land, Infrastructure, Transport and Tourism Ministerʼs
Infrastructure Maintenance Award Grand Prize● FY 2018 Tokyo Metropolitan Government Employee Award, Policy Issue
Division (Governor of Tokyo Award)⑨Hole Air Streamer (bladeless air blower)（●●）③ SPR construction method (sewage pipe renewal method)（●●）
Sewage Pipeline Renewal (SPR) method by wrapping the inside of existing
pipelines with a hard polyvinyl chloride (PVC) proﬁle● FY 2012 Okochi Prize, Okochi Memorial Prize ● FY 2013 Good Design Award● FY 2013 Ministry of Land, Infrastructure, Transport and Tourism Ministerʼs Award,
Circulation Path and Sewerage Award①Earthquake-resisting
construction method(ﬂoatless method)③SPR
construction method(sewage pipe renewal method)⑤ DO-Jet
construction
method④ Water surface
control device⑩Infrared laser
light-type continuous methane
concentration measuring device④ Water surface control device（●●●）

Construction method for suppressing pollutant outﬂows due to overﬂows
from combined sewage systems during rainy weather● FY 2011 Ministry of Land, Infrastructure, Transport and Tourism Ministerʼs Award,
Circulation Path and Sewerage Award● FY 2019 Japan Society of Civil Engineers Environmental Award● FY 2022 Japan Sewage Works Association (JSWA) Encouragement Paper Award(received in June 2022)②Total Information
System for Sewerage
Management (Total-ISM)④ Water surface
control device⑥ Omega Linerconstruction method(sewer renovation method)⑧Anaerobic and simultaneous
nitriﬁcation-denitriﬁcation
treatment method⑪Optical ﬁber
sensing box● FY 2012 Infrastructure Technology Development Award Excellence Prize ● FY 2022 Japan Society of Civil Engineers Technology Award⑥ Omega Liner construction method (sewer renovation method)（●）

Method for renovating sewer pipes by using steam heating to restore folded shape-memory polyvinyl chloride (PVC) pipes● FY 2018 Environment and Equipment Design Award First Prize ● FY 2023 Okochi Memorial Production Prize⑦ Ido Mill Meter * (time meter)（●）

Meter for measuring the operating time of well pumps to calculate sewage charges● FY 2013 Tokyo Metropolitan Government Employee Award, Grand Prize (Governor of Tokyo Award)

7● FY 2014 Nagasaki Prefecture Invention and Innovation Exhibition,
Prefectural Governorʼs Award● FY 2014 Award of the Japan Construction and Occupational Safety and
Health Association, First Prize● FY 2015 Monodzukuri Nippon Grand Award, Award of the Director-Generalof the Kyushu Bureau of Economy, Trade and Industry⑩Infrared laser light-type continuous methane
concentration measuring device（●）

Measuring device that calculates methane concentration by measuring
infrared absorption of methane gas● FY 2015 Society of Environmental Instrumentation, Control and Automation
Encouragement Award⑪Optical ﬁber sensing box（●）⑤ DO-Jet construction method（●）

Method for ground improvement and cutting/removing obstacles from underground by an ultra-high pressure jet

New ventilation system developed with the aim of improving the safetyof work in pipelines⑦ Ido Mill Meter(time meter)⑨Hole Air Streamer(bladeless air blower)⑫Ecolo-guard
construction method◉ For details of each award-winning technology, please refer to:https: //www.tgs-sw.co.jp/business/technical/c01/＊For details of the “Ido Mill Meter,” please refer to:

Device that transmits data on the sewage level measured using
optical ﬁber
● FY 2016 Society of Environmental Instrumentation, Control and Automation
Encouragement Award⑫Ecolo-guard construction method（●）

Coating-type lining method for removing deteriorated parts of concrete
structures and protection/repair of the concrete surface● FY 2018 Japan Sewage Works Association Encouragement Paper Award

https: //www.tgs-sw.co.jp/business/service/c03/

8

01

02

Supporting safe and pleasant life

Supporting the development of Metropolitan Tokyo

01- 01 Sewer maintenance service

01- 02 Night/holiday sewerage call center service

02-01 Sewerage Mapping and Information System (SEMIS)

02-02 Surveys of reconstruction projects

Based on the division of roles with the Bureau of Sewerage, Tokyo
Metropolitan Government, TGS is responsible for sewer pipe operation andmaintenance services (branch services) at branch oﬃces which the Bureau
has established at one location in each of the 23 wards of Tokyo.
When a road caves in or ﬂooding occurs, TGS works to prevent recurrenceby using original maps created by this company. The results of theseeﬀorts are utilized in preventive maintenance-type facility operation andmaintenance, such as measures for advance prevention of road cave-ins
and other accidents.
At work sites, we develop and propose various innovative solutions.
Feasible technologies based on excellent proposals are developed as newsite-originated technologies. One example is the “Smart Catch inside drop
pipe*,” which makes it possible to eliminate the outside drop pipes of manholes
which had been one cause of road cave-ins.
In the future, we will continue to improve the quality of our services andoperational eﬃciency by improving and increasing our eﬀorts to date.

TGS has been entrusted with operation of the sewerage call center service
during times (nighttime and holidays) when the Bureau of Sewerage, Tokyo
Metropolitan Government is closed as a one-stop service that receives all
telephone calls from customers, road administrators and others. Since this is a
front-line service with direct contact with customers, we strive to respondquickly and appropriately in order to improve customer services.

TGS is responsible for functional improvement, maintenance managementand data updating of the Sewerage Mapping and Information System (SEMIS)
operated by the Bureau of Sewerage, Tokyo Metropolitan Government.
We are contributing to stable operation of the sewerage system andimprovement of sewerage services by properly managing the SEMIS
system and making it possible to use a wide variety of data.

Because TGS is extremely familiar with the actual conditions at the site,
we have been entrusted with inspection services for trunk sewer lines,
sewage treatment plants and pumping stations which are scheduled forreconstruction. TGS prepares the drawings and other documents necessary for
issuing reconstruction work orders, contributing to smooth implementationof reconstruction projects being carried out by the Bureau of Sewerage.

Private sewer-related facilities consist of drainage equipment such as“drainage pipes” and “house inlets” located on residential land space. These areimportant facilities that connect the customer to the public sewerage system.
TGS provides inspection services at the actual site to check whether these
private sewer facilities are properly constructed and maintained. At the site,
inspections are conducted by TGS engineers with specialized knowledge
and a deep understanding of construction technology.

As part of support for design/estimation business of the Bureau of
Sewerage, Tokyo Metropolitan Government, TGS is engaged in thebusiness of assisting in designing, aiming to provide guidance for the
consultancy that has received an order for designing.
Also, TGS is assisting in preparing a design document, aiming tohelp to create a quantity calculation statement and data on a design
document for placing an order for construction based on a design
drawing, as well as providing functional improvement/maintenanceand management of
estimation systems.
Furthermore, TGS isproceeding with its
business eﬃciently bymaking good use oftele-working and thecompanyʼs original
quantity calculation
system.

TGS provides construction supervision support for achievement of thetargets set for reconstruction by the Bureau of Sewerage, Tokyo Metropolitan
Government. We perform a variety of work related to construction safety andensuring, beginning with technical guidance and coordination with
contractors from the administrative viewpoint.
In Tokyo, sewer pipe reconstruction is being carried out targeting 700 ha/yr.
TGS provides construction supervision support for approximately 70% ofthat work.
In the future, we will work to further improve business operation by actively
utilizing ICT and other innovative technologies with the aim of providing
quick and appropriate service.

General residences, etc.

Strainer

Survey work (surveys to check current condition)

ToiletIn sewer lines, manholes, inlets

Washing
machine

Wash
basin

Bathroomdrainage

Public sewer system

Sidewalk

Kitchen

Public/privateboundary

Drainage equipment (property of customers)

Public road

Vehicle roadway

Trap

Rainwater inlet

Safety management

Drainage
pipe

House
inlet

Trap

House
inlet

House
inlet

Conﬂuence
inlet

ManholeCollecting
sewerHouse inlet

Construction for road administrators and other companies

Other

Screen of Sewerage Mapping and Information System

02-04 Supervision of sewer pipe construction

Witnessing work

9

Survey for equipment reconstruction at
sewage treatment plant and pumping
station (survey of the current conditionof electrical equipment)

02-03 Sewer pipe design/estimation

Patrol and inspection※ The Bureau of Sewerage, Tokyo Metropolitan Government performs the design
work and construction supervision work.

Survey for trunk sewer reconstruction(core sampling survey)

01- 03 Inspections of private sewer-related services

Preparation of design documents for public inlet installation

Investigation of dangerous gases (e.g., H₂S)
and accident prevention action

Sewerage MaintenanceCo-operation

Telephone
reception
Emergency
response

Closure of storm surge tide gates (when a tsunami warning is issued for Tokyo Bay)

Operation

Collecting
sewer

Preparation of design documents for cleaning workand pipe inner investigation, support for supervision of the work

Extraordinary disasters, emergency accidents, etc.

Sewer pipe

Preparation of design documents for repair work,
support for supervision of the work

ReportPublic sewage inlet

Preventive maintenanceRepair work and operation（※）

Instruction

Earthquakes with seismic intensity 3 or greater
Observation of rainfall of 50 mm/hr or greater, heavy rainfall
and ﬂood warnings, approaching typhoons

Public/privateboundary

Response to customer inquiries, complaints, etc.

ReportInquiries on construction
Other sewerage-related guidance

Public passage
stormwater inlet

Coordination with road administrator and police

Instruction

Notiﬁcation

Sewerage system failure/trouble, etc.

Private land

Emergency response to road cave-in or sewer clogging, etc.

ReportPublic sewage
inletContent of work

Bureau of Sewerage (Sewerage Oﬃce)

Rain gutter

Response

Class ofwork

■ Table 1 Main sewer pipe operationand maintenance work under responsibility of TGSTGS Oﬃce (Branch Oﬃce)

Automatic transfer during Automatic call
Reportingtransfernighttime/holidays
Sewerage Call Center
Bureau of Sewerage, Tokyo
Metropolitan Government＊For details of “Smart Catch inside drop pipe”, please refer to:https://www.tgs-sw.co.jp/business/technical/c01

Telephone contact from customers, etc.
Notiﬁcation

Design/estimation service

Construction supervision support work

10

03

04

Creating a good water environment

Eﬀective utilization of resources and energy

03- 01 Maintenance management of sewage treatment plants and pumping stations

03- 02 Operation and maintenance of sludge treatment facilities

04- 01 Supply of recycled water

04- 02 Sludge recycling and use of renewable energy

In the 23 wards of Tokyo, there
are 13 sewage treatment plantsthat treat wastewater and 82
pumping stations for the related
pumping.
To ensure stable operation of
sewage treatment plants andpumping stations at all times,
TGS performs maintenance
Maintenance inspection work
management with priority topreventing equipment failures in advance.
Beginning in FY 2022, we were also entrusted with operation andmaintenance services for some sewage treatment plants by the Bureau of
Sewerage, Tokyo Metropolitan Government.

The sludge generated by the 13
sewage treatment plants in Tokyoʼs
23 wards is collected at 5 sludge
treatment facilities, and its amountreaches as much as about 60 million
m³ each year. At the sludge treatment
facilities, the physical volume ofthis huge amount of sewage sludge
Energy-eﬃcient incinerator
is reduced through the respective
processes of thickening, dewatering and incineration. We are also grapplingwith recycling of the ash that remains after the incineration process, forexample, through eﬀective utilization as a raw material for cement and as
granularity controlled ash.
TGS performs operational and maintenance management of all ﬁve sludge
treatment facilities and one sludge digestion facility.
As the sludge treatment process is extremely energy-intensive, it is importantto reduce energy consumption and CO₂ emissions.

Recycled water, which is produced by more advanced treatment processesof treated wastewater, is used as a valuable water resource that forms part of
the water circulation system in Tokyo.
In the 23 wards of Tokyo, recycled water is supplied from three sewage
treatment plants. TGS has been entrusted with this recycled water supply
service, and is responsible for operation management and maintenancemanagement at these recycled watersupply facilities.
Recycled water is eﬀectively utilized
as toilet water, etc. in approximately
200 facilities and is also used torestore clear streams in the 3
rivers in the Jonan area (Shibuya
River/Furukawa River, Meguro River,
Nomikawa River).
Seseragi-no-Sato ParkThe volume of sewage sludge as incineration ash is greatly reduced
through the treatment processes of “thickening → digestion → dewatering→ incineration,” and this incineration ash is recycled as a resource as muchas possible.
The sewage treatment plants also generate electric power by utilizing thewaste heat produced by sludge incineration and the energy of eﬄuent
drop (height diﬀerence) when the treated water is released.
TGS is responsible for some of the maintenance management work thatenables stable, eﬃcient operation of these businesses.

03- 04 Water quality testing/ investigations

04- 03 Construction surplus soil recycling

TGS performs water quality tests of water released from the sewage
treatment plants to ensure that it meets water quality standards. From FY
2022, we were responsible for all water quality management work at somesewage treatment plants.
In sludge treatment, we conﬁrm the properties of the sludge by sludge
testing and reﬂect the results in daily optimum operation management.
We also secure the stability and reliability of the supply of recycled waterby accurate measurement of the treated water quality and precise operation
management in the recycled water production process.
On the other hand, TGS not only performs regular testing, but also conducts
more specialized investigations and research in order to solve problems inthe ﬁeld from a scientiﬁc standpoint.

At the Nakagawa Construction-Generated Soil Improvement Plant, TGS
operates a service that produces improved soil for use in backﬁlling fromthe surplus soil generated by sewerage construction. During the 32 years
from the start of this service in 1988 to the end of FY 2019, the plant
produced 3.55 million m³ of improved soil.
After the plant opened, a complete renovation was carried out in 2003,
but aging deterioration also progressed at the facilities that were started
up after the renovation, and operation was suspended temporarily at theend of FY 2020.
At present, a new facility is under construction by the Bureau of Sewerage,
Tokyo Metropolitan Government.

Water samplingin water treatment process

General view of the Nakagawa
Construction-Generated Soil Improvement
Plant

03- 03 Operation and maintenance of the optical ﬁber network
An optical ﬁber network, laid inside sewer pipes, links the sewerage facilities
in the 23 wards of Tokyo. This network is used for remote monitoring andcontrol of pumping stations from sewage treatment plants, etc. TGS hascreated a system for regular inspections of the optical ﬁber facilities andcommunications equipment, 24-hour monitoring of the operating conditionof the network and quick response when problems occur.
Tokyo Metropolitan
Government Office

Sewage treatment
plant

Sewer system
officeBusiness system(OA system)

Optical fiber

Teleconferencing system, etc.
(FA system)

Pumping
stationPumping
stationRemote monitoring
and control

Diagram of the sewerage optical ﬁber network (image)

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Water quality
and related testing services

Production of improved soil

■ Granularity controlled ash (Super Ash) business

TGS developed a product called granularity controlled ash (“Super Ash”)
using incineration ash as the raw material, and is engaged in a business thatuses this product as a compounding agent for concrete.
Super Ash is contributing to recycling of sludge, as it can be used as a raw
material for the production of concrete secondary products such as Humepipes, manholes, concrete segments, etc. which are used in public works
construction in Tokyo.

Recycling

Granularity controlled ash(Super Ash)

■ e-CON

Concrete secondary products

TGS jointly developed the new type of concrete e-CON, in which industrial
byproducts such as blast furnace slag, ﬂy ash, etc. and Super Ash areeﬀectively utilized as a substitute for cement.
Since e-CON not only has
Test body after immersion in 5% sulfuric
excellent sulfuric acid corrosion
acid aqueous solution for 112 days
resistance, but also reducescarbon dioxide (CO₂) emissions
in the production process
by about 80%, use of thisnew product contributes topreservation of the global
environment.
e-CON
Ordinary cement

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05

Responding to issues at the site in Japan and other countries

A foundation of human resources ‒ People are the treasure

05-01 Technology development aimed at commercialization

05-02 Domestic and overseas expansion of developed technologies

01 A diverse team of active colleagues

02 A workplace where employees can shine

TGS is conducting joint research with the Bureau of Sewerage, Tokyo
Metropolitan Government and private companies on the theme oftechnology development directly linked to sewerage services. In addition,technology development themes are selected from among various issues
that arise in the entrusted services performed by TGS, as part of active
eﬀorts to promote development of operation site-originated technologies.
Together with aiming at practical application and commercialization of
the developed technologies, we are also working to continuously reﬁne
and improve technologies in cooperation with our development partners.

The technologies developed by TGS
are contributing to problem-solving
not only in the Tokyo seweragesystem, but also in seweragebusinesses in other parts of Japanand overseas.
In order to expand the use of
TGS-developed technologies in Japan
Signing ceremony for a Memorandum ofand other countries, it is necessary to
Understanding for joint development of
win a high public evaluation for
TGSʼs water surface control device(Munich, Germany)
these technologies, and eﬀective
PR activities to encourage adoption are also required in addition to theproven record of Tokyo sewerage system. It is also important to respond tothe conditions and thinking in other regions and countries, for example, theapplicable technical standards in each area, and local business customs
must be considered, especially in overseas countries.
We are making these eﬀorts in collaboration with our joint development
partners with the cooperation of construction method associations andother related parties.

What supports the sewerage system in the Tokyo metropolitan area is theindividual employees. Because TGS values the idea that “it is precisely people
that are a companyʼs asset (= treasure),” we work hard to hire and train humanresources.
Our company, which aims is to achieve a sustainable society through thepower of sewerage, is made up of diverse human resources who possess hightechnical capabilities and a strong sense of mission.
Employees in various types of jobs mutually cooperate to support the Tokyo
sewerage system. These include the people in civil engineering, who areresponsible for sewer maintenance service, the mechanical and electricalengineers who manage sewage treatment plant and sludge treatment
facilities, environmental inspection personnel in charge of water quality
management, and the business staﬀ who are the management foundationof the company.

By providing a workplace environment where employees can continue towork vigorously and with a feeling of security and realizing diverse workstyles,
we aim to be a company where each employee can shine and all employees
can work in mutual cooperation.
So that employees can maintain good physical and mental health and satisfy
the balance of work and family life, TGS has established a vacation and leavesystem that includes 20 days of paid vacation each year, summer vacation,
leave for personal events such as weddings and funerals, long continuous
holidays, and time oﬀ for childbirth and child rearing, nursing care and care for
elderly parents. We have also established a support system for a complete
annual medical checkup and a mental health consultation system as eﬀorts
that consider a work-friendly environment and employee health, and we are
expanding and improving our welfare and beneﬁt program for younger
employees, for example, by oﬀering fully-furnished rental apartments incompany dormitories.
The TGS career advancement system makes it possible for outstanding

Developed technology(SPR construction method)
Photo by Ray Shirao05-03 Contributing to the improvement of overseas project

05-04 Support for Engineer Training and Study

Utilizing the strengths of technological capabilities and management
know-how that TGS has cultivated until now, we are promotinginternational expansion of Tokyo-originated sewerage technologies. In
Malaysiaʼs Langat Sewerage Project, we provided technical support to
Malaysian government agencies for all aspects of the sewerage system,
through processes ranging from planning to design, construction andoperation. This 12-year project was completed with no problems in
November 2022.
In addition to participating in overseas sewerage projects based on
the needs of large metropolitan
areas in other countries throughcollaboration/cooperation with
the Bureau of Sewerage, Tokyo
Metropolitan Government andJapanʼs national government andadministrative agencies (JICA, etc.),
we are also involved in technology
Hand-over ceremony of the Langat
exchanges though participation
Sewerage Project (Malaysia)
in international conferences andother activities.

Sewerage services in Tokyo are conducted by three organizations, the Bureauof Sewerage of the Tokyo Metropolitan Government, private-sector companies
and TGS. In order to provide sewerage services consistently, it is important toensure transmission of the technologies and know-how developed by thesethree organizations. TGS established the Sewerage Training Center in 2009and began training Bureau of Sewerage staﬀ and employees, and in 2013,
we started the management and operation of training for private companies
at the Sewerage Technology Training Center opened by the Bureau of
Sewerage, thereby contributing to human resources development for thethree parties. To deepen the public understandingof the history of sewerage, TGS also conducts
tours of the former main pump house of the
Mikawashima Sewage Treatment Plant, which has
been designated as an important cultural property.
TGS has also been entrusted with qualiﬁcation
test and renewal course services for engineers
responsible for private sewer works, including thePracticing walking
nationwide Japan Sewage Works Association (JSA).
in water in a sewer pipe

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For details on engineers responsible for sewer works, please refer to:https://www.tgs-sw.co.jp/haisui-enjineer/

employees to rise to managerial positions at an early stage and supports the eﬀorts
of highly motivated employees who are eager to take on diﬃcult challenges.

03 Training employees and self-study

In addition to newly-graduated and hired young employees, we also have anumber of veteran employees such as experienced persons from othercompanies, persons dispatched from the Tokyo Metropolitan Government andpersons with administrative experience. Thus, employees with a wide rangeof ages are working together, taking full advantage of their respective
technologies and experience.
With many of our veteran employees expected to retire in the coming years,
we will look for people with spirit, who will protect the water environment andcontribute to the safety and growth of Tokyo together with us.

With expanded hiring of young employees, thenumber with limited experience of sewerage in
general is also increasing. To provide sewerage
services consistently over the coming years, TGS
works to ensure transmission of the technologies
and know-how cultivated in the past reliably, toeach individual employee, and to train the humanresources that will support a sustainable society.
Experiential-type actual
Beginning with new employee training andsite training
on-the-job (OJT) training by employees with a wealth of practical experience,
we provide training in the 2nd and 3rd years after hiring, as well as training
when employees are promoted to higher positions, giving employees
opportunities to acquire knowledge corresponding to their careers.
In practical training, in addition to “desktop” exercises, we also conduct
full-scale model training at the Sewerage Technology Training Center, andexperiential-type actual site training using actual equipment and machinery.
To support employeesʼ desire for self-improvement, we oﬀer ﬁnancial
support for those who wish to acquire sewerage-related qualiﬁcations such as
sewage engineering or technology certiﬁcations, as well as in-house training
and online training for acquiring qualiﬁcations, with the aim of improving
their technical levels.

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