Environmental Programs Implemented
by Water Utilities in JapanJWRC Study Group for International Comparison of Water Supply Services
September 2019

Contents
P1

About this document

P1Water utilities and environmental programs presented

P1

Environmental program at each water utility

P2

Saitama City Waterworks Bureau: Inverter Pumps to Reduce Energy and CO2 Emission

P3

Kanagawa Prefectural Public Enterprises Agency: Solar Power Generation Utilizing Facility Space Efficiently

P4

Yokohama Waterworks Bureau: Management of Water Catchment Forest and Source Water Protection

P5

Chiba Prefectural Public Enterprises Bureau: Hydropower Covers 2.3% of Entire Energy Requirements

P6

Osaka Water Supply Authority: Economical Water Transmission Based on Demand Estimation

P7

Bureau of Waterworks, Tokyo Metropolitan Government: Energy Efficient Pump Cut 20% of Electricity Use

P8Water and Sewer Bureau, City of Kitakyushu: Water Treatment Utilizing Microorganisms

P9References

About this document
This document aims to present information on various environmental programs implemented by Japanesewater utilities. It was compiled by the Study Group for International Comparison of Water Supply Services(Secretariat: Japan Water Research Center), and the information presented within was provided by theseven water utilities in Japan, that are also members of the Study Group.

Water utilities and environmental programs presented
The map below shows the name of the seven water utilities and their environmental programs presented
in this document. Please note that although only one type of program is presented per utility, any of themhas implemented different environmental programs not presented in this report.

Environmental program at each water utility
Environmental programs implemented at each water utility are presented in the following pages.

1Saitama City Waterworks Bureau

Inverter Pumps to Reduce Energyand CO2 Emission

Water Utility

Background/Outline

Retail water supply (public)

The electricity consumption involving Saitama City’s water supply costs JPY
3.71 per cubic meter. This number is relatively small among the largest water
utilities in Japan, yet due to its rather plain terrain in the service area, watermust be pumped for distribution and that results in a large amount of electricity
consumption and CO2 emission.
Given the situation, the city has been replacing the pumps with those withinverter motors to reduce the energy involved in distribution.

Population ServedProgram/Outcome

1.29 million（FY2017）

The city has been replacing five pumps per year. Of the 89 pumps now inservice (breakdown: 25 at water treatment plants and 64 at distribution
reservoirs), 61 pumps have been replaced with inverter types by FY2017.
Through the replacement program, the city has promoted a more efficientwater management by reducing the energy consumption required for water
distribution. The table below shows the CO2 reduction at three distribution
reservoirs as a result of the pump replacement program.

Saitama City Waterworks
BureauType of Water Supply

Service Area
217.43 km2（FY2017）

Environmental Program
Inverter pump

OutcomeEstimated CO2 reduction from adopting inverter pumps
Name of distribution
reservoir

Number of pumps

Estimated C02 reduction(t) per year

Shirahata

6242

Minami Shimoarai

5207

Omagi

469

 Improved distribution control
 Reduced energy consumption
and CO2 emission

2Kanagawa Prefectural Public Enterprises Agency

Solar Power Generation Utilizing
Facility Space Efficiently

Water Utility
Kanagawa Prefectural PublicEnterprises Agency

Background/Outline
The Agency had put covers over the filtration basins and other structures atits Samukawa Water Treatment Plant to prevent potential water contamination
by foreign substances. In FY2004, they installed a solar power generation
system on top of these covers by utilizing the available space efficiently.

Type of Water Supply
Retail water supply (public)

Population Served
2.8 million (FY2017)

Service Area
809 km2 (FY2017)

Environmental Program
Solar power generation

Outcome Making the best of available
facility space Reduced CO2 emission

Program/Outcome
The solar power generation system, which can produce power of 120 kW,
started operation in February 2005. The covers on which the solar panels areplaced are arch-shaped and movable, and made of fiber reinforced plastics,
which are light and very good in strength. All the power produced from thesystem is consumed at Samukawa Water Treatment Plant.
For general visitors to the plant, the Agency has installed electronic panels
showing in real-time the amount of power being produced from the system.
This is a public relations effort to show the Agency’s environmental consciousness
and to raise public awareness about solar power generation. The construction
cost of the system was subsidized by central government through its new energy
use promotion program.
In FY2017, the solar power system reduced approximately 48,000 kg of
CO2 emission and the amount of power generated from the system was around
98,000 kWh, which corresponds to the power use at about 26 residential
houses.
Another solar power
generation
systemisinstalled at some water
related facilities just outsideof the Samukawa plant’s
premises. Their generated
power is sold to a local
electronic company.

Solar power generation system on therooftop of a water treatment plant3Yokohama Waterworks Bureau

Management of Water Resource
Forest and Water Source Protection

Water Utility
Yokohama Waterworks Bureau

Type of Water Supply
Retail water supply (public)

Population Served

Background/Outline
In 1916, Yokohama City purchased from
Yamanashi Prefecture what is now known as“Doshi Water Resource Forest”, a forest area
where one of Yokohama’s water supply sources,
Doshi River, begins. The purchase was made toprotect and conserve the river’s water quality.
As of 2019, the Doshi Water Resource Forest
stretches 2,873 hectares of land and comprises
36% of Doshi Village, which is locatedapproximately 55 km west of Yokohama City.

Doshi River

3.7 million (FY2017)

Program/Outcome
Service Area
436 km2 (FY2017)

Environmental Program
Water source protection

Outcome Improved water recharge
function of a forest Water quality protection of ariver CO2 reduction

Soil protection is a key to forest conservation. The Doshi forest has manydifferent types of trees, and accumulated fallen leaves help its soils keep highwater holding capacity, which enriches the source water. Therefore, the city
has regularly thinned out conifers such as cedars and cypresses and kept theforest mixed with both conifers (needle-leaved trees) and broad-leaved trees.
On the other hand, approximately 60% of the forest area that the city does
not own had not been managed as well as it would have been desired, having
raised concern over the forest’s water recharge function being adverselyaffected. This led the city to initiate a special volunteer program in 2004, andto this day as many as 17,000 volunteers have helped conserve 70 hectaresof the privately-owned portion of the Doshi forest. To support volunteer
activities, the city created a fund in 2006 to receive donations from citizens
and private companies and to relocate some of the revenues generated fromselling its official bottled water.
The city and Doshi Village have also
co-founded another fund to help withthe conservation efforts and to stimulate
local economies in Doshi area. Other
conservations efforts by the city include
financial support to Doshi Village fortreating its residential wastewater anda collaborative conservation program
for the Doshi forest in cooperation with
Volunteers thinning out trees
privatecompaniesandotherstakeholders.
4Chiba Prefectural Public Enterprises Bureau

Hydropower Covers 2.3% ofEntire Energy Requirements

Water Utility
Chiba Prefectural PublicEnterprises Bureau

Type of Water Supply
Retail water supply (public)

Population Served

Background/Outline
The Waterworks of Chiba PrefecturalPublic Enterprises Bureau installed smallhydropower
generators on theMakuhari Pump Station (Chiba City) andthe Myoden Pump Station (IchikawaCity) in 2008. This is an effort to reduce
the electricity required to operate thetwo stations. Two more generators werealso installed in 2014 on the KitaFunabashi Pump Station (FunabashiCity).

Hydropower generator atthe Makuhari Pump Station

3.03 million (as of March 2018)

Program/Outcome
Service Area
566 km2 (as of March 2018)

Environmental Program
Small hydropower generation

The hydropower generation program is cooperated by the Waterworks,
which has provided hydro energy, and The Tokyo Electric Generation
Company, which has built and operated relevant power plants. The electricity
generated from the program is supplied to the pump stations where thegenerators were installed.
The annual amount of energy produced from the three pump stations isapproximately 3.3 million kWh, which accounts for 2.3% of the annualelectricity consumption by the Waterworks. In total, the hydropower
generation contributes to approximately 1,600 t of CO2 reduction a year.

OutcomeCO2 reduction from the hydropower generation
Pump station

Output（kW）

Annual power
generation（kWh)

Annual reduction
in CO2（t）

Makuhari

350 kW

1.37 million kWh*1666 t

Myoden300 kW

1.05 million kWh*2510 t

Kita-Funabashi

235 kW

0.92 million kWh*3

447 t

CO2 reduction* Equal to the consumption of 380*1, 290*2, or 260*3 households.

5

Osaka Water Supply Authority

Economical Water Transmission
Based on Demand Estimation

Water Utility

Background/Outline

 Wholesale water supply(public)
 Retail water supply (public)

The Water Transmission Management Center of the Authority has stably
operated and monitored its pumping stations for water transmission. This has
been enabled by a prompt and accurate analysis of various facilities’operational data through the use of wireless data transmission units,supervisory control devices, and other IT equipment. Also, the Center has
operated in a financially economical manner by increasing the amount oftransmission during evening hours and thus taking advantage of cheapernight tariffs of electricity.

Population Serviced

Program/Outcome

Osaka Water Supply Authority

Type of Water Supply

6.1 million (FY2016)

Service Area
1,680 km2 (FY2015)

Environmental Program
Efficient water management

Outcome Control of water pressure
fluctuation
 Cost reduction for electricity
consumption
 Reduction of contracted
electricity rates

Normally, the operation of transmission pumps requires a large amount ofelectricity. The Center has estimated daily water demand based on various
indicators including historic demands, weather patters, days of the week, airtemperature, and utilizes the estimates for efficient and economical watertransmission. More specifically, they have transmitted water to clear water
reservoirs during evening hours and using the stored water to meet the day
time demand which is normally larger than that of night time. This enables theCenter to not only reduce the electricity cost required to operate transmission
pumps but to minimize the number of turning-on/ff of the pumps and thus
better control water pressure fluctuations and stabilize the amount oftransmission, all of which contribute to an ecnomical and reliable watersupply.
In case there are multiple routes for transmission, they calculate how mucheach route would cost based on the characteristics of relevant transmission
pipes and pumping stations, and take the calculation results into considerationin order to operate in the most efficient way possible.
Example of estimated daily water demand

6Bureau of Waterworks, Tokyo Metropolitan Government

Energy Efficient Pump Cut 20% ofElectricity Use

Water Utility

Background/Outline

13.4 million (FY2017)

The amount and pressure of water distributed
from water treatment plants and water supply
stations are normally controlled by adjusting
pump speed. Traditionally, Tokyo Metropolitan
Government has used liquid resistors to adjust
pump speed, but because theirenergy
efficiency drops in the low speed range, theutility has been replacing aged pumps withmore energy efficient ones such as those withinverter controls. This way, the utility has
reduced the amount of electricity required tooperate pumps.

Service Area

Program/Outcome

1239.27 km2 (FY2017)

The 2nd Inagi Pump Station, built in 1980 in the southern part of Tokyo, isa water transmission facility to send water up to water supply stations
located on high land from water treatment plants located on low land.
When the pump station underwent a facility renewal in 2016, the utility
replaced the existing pumps with new ones of inverter controls in order toraise energy efficiency. After the replacement, the amount of electricity
required to transmit one cubic meter of water was reduced by 19%. The
graph below compares the electricity requirements before and after thepump replacement.

Type of Water Supply
Retail water supply (public)

Population Served

Environmental Program
Energy efficient pump

OutcomeReduced electricity consumption

Distribution pump atKamiigusa Water
Supply Station

Energy reduction before and after pump replacement at the 2ndInagi Pump Station
Electricity required to transmit 1 m3 of water (kWh/m3)

Bureau of Waterworks, Tokyo
Metropolitan Government

FY2015: liquid resistors
FY2017: Inverter control

Averagereduction: 19%456789 10 11 12123Month7

Water and Sewer Bureau, City of Kitakyushu

Water Treatment
Utilizing Microorganisms

Water Utility
Water and Sewer Bureau,
City of Kitakyushu

Type of Water Supply
 Retail water supply (public) Wholesale water supply(public)

Population Served1.0 million (FY2017)

Background/Outline
The water quality of Onga River, the city’s primary water source, has been
adversly affected by the urbanization occurring in upstream regions. Increased
pollutants due to the wastewater have resulted in algae bloom and intensifiedmusty odor.
These pollutants and musty odor are difficult to remove by the traditional
water treatment process, hence City of Kitakyushu has developed an original
counter measure called Upward Biological Contact Filtration System (U-BCF)
and installed that system at its Honjyo Water Treatment Plant in 2000 and Ano
Water Treatment Plant in 2003. The U-BCF can be installed easily as it can beinstalled at the beginning of existing water treamtnet processes.
City of Kitakyushu has activeily promoted the U-BCF outside of Japan, andin 2013 the Haiphong Water Supply One Member Company Limited - thewater utility supplying Haiphong City in Vietnam - installed a U-BCF at theirVinh Bao Water Treatment Plant.

Service Area

Program/Outcome

270.16 km2 (FY2017)

The core function of the U-BCF is to artificially reproduce - in a more
efficient manner - a natural environment in which aquatic microorganisms
decompose micropollutants. The U-BCF uses granular activated carbon as filter
media, and due to its porus, rugged, uneven surfaces, the granular activatedcarbon provides a much better environment for microorganizams to live in,than, for example, pebbles in a riverbed. The U-BCF’s upward water flows
prevent the filter layers from getting clogged while making the granular
activated carbon being moved by the flow and contact with much more water,
enhancing the decomposition process by microorganisms.
The U-BCF can remove, without using chemicals or large electircity, ammonia
nitrogen, dissolved manganese, and musty-odor causing substances likegeosmin existing in raw water. This feature contributed to less chemical use
and more stable treatment process at the existing process.

Environmental Program
Upward Biological Contact
Filtration System (U-BCF)

Outcome Reduced chemical use Improved stability of watertreatment
 Removed pollutants and odor

8

References
Saitama City Waterworks Bureau
Saitama City Waterworks Bureau. Revised Edition of the Second Long-Term Vision of Saitama City Water
Supply Services. [in Japanese.]https://www.city.saitama.jp/001/006/002/048/001/p039608_d/fil/cyokikoso_kaiteiban.pdf――. Annual Report of Water Supply Services FY2017. [in Japanese.]https://www.city.saitama.jp/001/006/002/048/003/p012074_d/fil/H29annualreport.pdf――. Environmental Accounting FY2017. [in Japanese.]https://www.city.saitama.jp/001/006/002/034/002/p007054_d/fil/29kankyoukaikei.pdf――. Report on the Plans and Measures Taken against Global Warming at the Waterworks Bureau
FY2017. [in Japanese.]https://www.city.saitama.jp/001/006/002/034/002/p012256_d/fil/H29chikyuondankataisaku.pdf

Kanagawa Prefectural Public Enterprises Agency
Kanagawa Prefectural Public Enterprises Agency. About Solar Power System. [in Japanese.]
http://www.pref.kanagawa.jp/cnt/f990/p10179.html

Yokohama Waterworks Bureau
YokohamaWaterworks

Bureau.

Conservation

of

Doshi

Water

Source.

[inJapanese.]

http://www.city.yokohama.lg.jp/suidou/kyoku/torikumi/suigen-hozen/――. Doshi Water Catchment Forest. [in Japanese.]
http://www.city.yokohama.lg.jp/suidou/kyoku/torikumi/suigen-hozen/pdf/doushisuigenrinpuran.pdf

Chiba Prefectural Public Enterprises Bureau
Chiba Prefectural Public Enterprises Bureau. Annual Report of Water Supply Services FY2017. [in Japanese.]

Osaka Water Supply Authority
Osaka Water Supply Authority. Commemorative Publication of Establishing Osaka Water Supply Authority(Chapter 1). [in Japanese.]
http://www.wsa-osaka.jp/event-pr/pamphlet/kinenshi1.pdf

9

Bureau of Waterworks, Tokyo Metropolitan Government
Bureau of Waterworks, Tokyo Metropolitan Government. Environmental Report 2018. [in Japanese.]https://www.waterworks.metro.tokyo.jp/suidojigyo/torikumi/kankyo/pdf/h30/30hokoku-01.pdf

Kitakyushu City Water and Sewer Bureau
Kitakyushu City Water and Sewer Bureau. Advanced Water Treatment Facilities. [in Japanese.]
http://www.city.kitakyushu.lg.jp/files/000725592.pdf――．Haiphong City in Vietnam installed U-BCF - Kitakyushu City’s Advanced Water Treatment System. [inJapanese.]https://kyodonewsprwire.jp/prwfile/release/M100123/201306112479/_prw_PR1fl_59C4yp3W.pdf
Japans Water Research Center. Study on International Comparison of Water Supply Services. [in Japanese.]
http://www.jwrc-net.or.jp/chousa-kenkyuu/comparison/domestic01_05.pdf――. NewTap.
http://www.jwrc-net.or.jp/aswin/en/newtap/report/NewTap_Japan_002_04.pdf
The Japan Society of Industrial Machinery Manufacturers. Upward Biological Contact Filtration System. [inJapanese.]
http://www.jsim.or.jp/newsPDF/kankyo05.pdf
Suido Sangyo Shimbun (water industry newspaper). Upward Biological Contact Filtration System. [inJapanese.]
http://www.suidou.co.jp/library/dictionary-waterworks/pdf2017/2017-111.pdf

10Japan Water Research Center
T +81-3-5805-0264
W www.jwrc-net.or.jp/english/index.html
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