Water Utility Information (FY 2014)
Name of utility:

Chiba Prefectural Waterworks
BureauService type:

Water service provider

Administrative
population:

3.5 million people

Start of service:

1936

Population served:

3 million people

Service area:

566.37

Householduse

690,000

m /dCommercial
andinstitutional
use:
Break

120,000

m /d

Others:

50,000m /d

Fromwholesalesupplier

13,000

m /d

2

km

Water supply volume

Average daily watersupply:

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870,000

m3/d

down

Average daily watersupply per capita:

292

Effectiveness:

98.7

L/per
son/
d
%

NRW:

5.3

%

3

3

3

3

Service coverage:

96.4

%

Revenue water:

94.7

%

Water loss

1.6%

Water rates
1,020

181.85(including taxes)*Calculation conditon: The service pipe has a 13mm diameter. The fixed charge is 410.10
yen/month. The volumetric charge is 61.56 yen/m3
up to 10m3.

Water rates for 10m3/month:

Water production cost:yen

yen/m3

Water supply cost:

202.39yen/m3

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Water Treatment Plant andFacilities (including water fromwholesale supplier):

Capacity

Treatment process

Kuriyama WTP

186,000

m /d

3

Coagulation/Sedimentation
Surface water+ Rapid filtration + Chlorine(river)disinfection

Kashiwai WTP(west wing)

360,000

m /d

3

Coagulation/Sedimentation
Surface water+ Rapid filtration + Chlorine(river)disinfection

Kashiwai WTP(east wing)

170,000

3m /dCoagulation/Sedimentation
Surface water + Rapid filtration + Ozone +(lake)
Powdered activated carbon +Chlorine disinfection

Hokuso WTP

126,700

m3/d

Coagulation/Sedimentation
Surface water+ Rapid filtration + Chlorine(river)disinfection

m3/d

Coagulation/Sedimentation+ Pre-ozonation + Rapid
Surface water
filtration + Ozone +(lake)
Biological activated carbon +Chlorine disinfection

Fukumasu WTP

Pipieline length:

Water source

90,000m /d

3Surface water(river)Coagulation/Sedimentation+ Ozone + Biologicalactivated carbon + Rapid
filtration + Chlorine
disinfection

261,300

m3/d

－

－

1,254,000

m3/d

Chiba Nogiku-noSato WTP

60,000

Water forwholesale supplly
Total

8,970

Conveyance:

70

km

Distribution:

8,730

km

km

Trans
missio
n:
Other
s:

170

km

－

km

・Cast iron: 8,530 km
Type of material: ・Asbest cemento: 6.9 km
・Steel: 167 km
・Number of employees: 875
・Seismic reinforcement rate of pumping stations: 79.8%
・Seismic reinformcement rate of distribtuion reservoirs: 56.5%
Other information: ・Maximum daily supply: 1 million m3
・Maxiumum facility utilization rate: 82.8% (Maximum daily supply/treatment
capacity)
・Facility utilization rate: 69.2% (Average daily water supply/treatment capacity)
・All the infromaiton above (except for the length of the lead service pipe) was
cited from the Annual Report FY2014 of the Chiba Prefectural Waterworks
Remarsk:
Bureau.
・The length of the lead service pipe was cited from the Annual Report FY2013.

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Water Utility Information (FY 2014)
No.1
Nogiku-no-Sato
WTP

Service area
Case study facility

Chiba Nogiku-no-sato
Purification Plant
Hokuso Purification Plant●●
Kuriyama Purification Plant●Kashiwai Purification Plant●Fukumasu Purification Plant

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Case Study Report (Chiba Nogiku-no-Sato Water Treatment Plant)
Case #1: Chiba Nogiku-no-Sato Water Treatment Plant
Key word:

Advanced water treatment (ozone + biological activated carbon), Surface water (river),
Odor control, Elimination and consolidation of facilities, Private sector involvement<Outline and characteristics>●Purpose of construction
The Chiba Nogiku-no-Sato Water Treatment Plant began operation in October 2007. It’s aseismic resistant plant built to replace the old Kogasaki (1940) and Kuriyama (1958) Water
Treatment Plants. Upon its completion, the Kogasaki was demolished in 2007. The
Kuriyama will also be out of service in 2023, when the Chiba Nogiku-no-Sato will havecompleted an ongoing construction of a new water treatment facility that will fully replace
the capacity of the Kuriyama.

Outline:

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●System features
・Safe and high quality water supply: Ozone + biological activated carbon (advanced water
treatmetn) to control musty odor as well as bad smells from fish eggs
・Emergency preparedness: Seismic resistance reinforcement of water facilities andpreparation of on-site water supply stations for residents in the event of an emergency
・Private sector involvement: Private Finance Initiative (PFI) for the construction andoperation of its drainage facility. The operation contract is for 20 years. Among others, thecontract provides for the use of surplus soil from on-site excavations as raw materials of
improved soil for reclamed land.
・Environmental measures: Solar power generation system for clean energy
・Recreational area for the public: areas on the top of reservoirs is open to public access forrecreational use.
・Barrier-free design: assures all the visitors a comfortable access to the buildings andfacilities on the premises<Others>
The service area includes portions of the Matsudo City, Ichikawa City, and Funabashi Cityin the Chiba Prefecture.

Address:

Kuriyama 478-1, Matsudo City, Chiba Prefecture

Land area:

125,000 m2

Water
treatment
process:

Coagulation/Sedimentation + Ozone + Biological Activated Carbon + Rapid filtration +Chlorine disinfection

Capacity:

・Final capacity: 246,000 m3/d (to be complete in 2023)
・Current capacity: 60,000 m3/d・Additional capacity under construction: 186,000 m3/d

Water source: Surface water (Edo River of the Tone River System)

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Case Study Report (Chiba Nogiku-no-Sato Water Treatment Plant)■Affected by upstream river conditions because of the plant's downstream location■Frequent oil spills■Algae blooms tend to increase the pH and adversely affect the coagulation process■An issue of musty odor and fish eggs flowing from upstream
Raw water
quality:

Chemicaldose:Start ofoperation

P
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Sulfuric acid (pH adjustment), Sodium hydroxide (pH adjustment),
Polyaluminum chloride (coagulation), Sodium hypochlorite (disinfection)
Oct-07

Aerial view

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<Average raw water quality in FY2014 (maximum)>・Turbidity: 11 degrees (24 degrees) ・Hardness: 60mg/L (68mg/L) ・TOC: 1.5 mg/L (2.9mg/L)
・pH: 7.7 (8.7) ・Color: 10 degrees (64 degrees) ・Geosmin: 0.002 μg/L (0.004 μg/L)
・2-MIB: <0.001 μg/L (0.005 μg/L) ・TON: 21 (40)

Layout:・Pre-chlorination
Sulfuric acid ・(Pre-alkali agent)

IntakeTreatment
process flow
diagram:Receivingwell

Advanced Water
Treatment
Pre-PACl

Rapid
mixingFlocculation

Chemicalsedimentat
ion

Ozone

Pre-chlorination

Secondary
Chlorination

Activated
CarbonSecondary
Chlorinatio
n mixing

Powdered activated carbon(depending on raw water quality)
SecondarymixingSecondary
PACl

Rapid
filtration

Tertiary
Chlorinatio
n mixing

Reservoir

・Tertiary chlorination
・(Secondary alkali agent)

Pumping

Chlorineadjustment

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(depending on raw water quality)
SecondarymixingSecondaryRapid
filtration

Tertiary
Chlorinatio
n mixing

Reservoir

・Tertiary chlorination

Pumping

Chlorineadjustment
PACl
alkali agent) Plant)
Case Study Report (Chiba Nogiku-no-Sato
Water・(Secondary
Treatment

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Instake point

Grit chamber

Sedimentation basin

Ozone diffusing pipe

Activated carbon adsorption basin
Pictures:

Rapid filtration basin

6Case Study Report (Chiba Nogiku-no-Sato Water Treatment Plant)●Solar Power Generation System for CO2 reduction
Maximum output: 57.8 kw (daily output varies depending on the weather)
Installation area: 410 m2 (324 solar power generation modules)
Usage: suppies power for ventilation fans in the central control building

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Other
facilities:

Datadisplay
display
Data collector Data
Solar panel

Converter

Solar panel

Electricity
company

Switch board
to machinery& equipment

Order/contrac
PFI (drainage facility)t:
Other information:
List of references (URL)●Chiba Prefectural Waterworks Bureau. Annual Report FY2014.
http://www.pref.chiba.lg.jp/suidou/souki/toukeidata/h26zigyou-nenpou.html● Chiba Prefectural Waterworks Bureau. Brochure of the Chiba Nogiku-no-Sato Water Treatment Plant(September 2012).
●Chiba Prefectural Waterworks Bureau. Chapter 8: Water Quality Management, the Environment Report
FY2014.
https://www.pref.chiba.lg.jp/suidou/souki/zigyougaiyou/kankyoukaikei/houkokusho-h26.html●Association of Water and Sewage Works Consultants Japan. Suikon 2015 Vol. 50.
http://www.suikon.or.jp/suikon/vol.50/suikon50_009.pdf

7Water Utility Information (FY 2014)
Name of utility:

Public Enterprises Agency
Kanagawa Prefectural Government

Service type:

Water service provider

Administrative
population:

3.03 million people

Start of service:

1933

Population served:

2.8 million people

Service area:

808.59Household use

664,000

m /dCommercial
and Industrialuse:

152,000

m /d

Others:

42,000m /d

From wholesale
supplier

25,000m /dService coverage:

99.8

%

km

2

Water supply volume

BasicsAverage dailywater supply:

880,000

3

Break
down

m /d

3

3

3

3

Average dailywater supply percapita:292.6

L/person/dEffectiveness:

92.7

%

Revenue water:

88.5

%

NRW:

11.5

%

Water loss

6.7%

Water rates
1,043
Water rate for 10m3/month:

Water productioncost:

164.14
Name

Facilities

Samukawa WTP

Water Treatment Plant
and Facilities(including water fromwholesale supplier):(including taxes)

yen**Calculation condition: The fixed charge is 1,420 yen/twomonths. The volumetric charge is 128 yen/m3 from 17 to 30 m3 =1,932 yen x taxes x 1/2

yen/m

3

Water supply cost:

156.01yen/m

3

Capacity

Water source

Treatment process

750,000 m3/d

Surface water

Coagulation/sedimentation + Rapid
filtration + Chlorine disinfection

Sedimentation + Slow filtration +Chlorine disinfection
Coagulation/sedimentation + Rapid
filtation + Chlorine disinfection

Tanigahara WTP

242,800 m /d

Subsoil water
Surface water

Kamasawa WTP

720 m3/d

Surface water

Membrane filtration + Chlorine
disinfection

Ochiai WTP

1,620 m3/d

Surface water

Membrane filtration + Chlorine
disinfection

Wada WTP

360 m3/d

Surface water

Membrane filtration + Chlorine
disinfection

Oyama WTP

1,100 m3/d

Surface water

Membrane filtration + Chlorine
disinfection

Sokozawa WTP

470 m3/d

Surface water

Membrane filtration + Chlorine
disinfection

Toya WTP

5,550 m3/d

Subsoil water

Coagulation/sedimentation + Rapid
filtration + Chlorine disinfection

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Facilitie

Water Treatment Plant
and Facilities(including water fromwholesale supplier):

Nagano WTP

500 m3/d

Subsoil water

Membrane filtration + Chlorine
disinfection

Itarih WTP

4,400 m3/d

Spring water

Membrane filtration + Chlorine
disinfection

Shinanoki WTP

3,300 m3/d

Spring water

Membrane filtration + Chlorine
disinfection

Midono water
source12,800 m3/d

Spring water

UV treatment + Chlorine disinfection

Others (Kissawa
etc)

1,700 m3/d

Ground water

Chlorine disinfection

Water fromwholesale supplier

669,400 m3/d

－

－

Total

Pipes

Pipieline length:

9,217

1,694,720

km

3

m /d

Conveyance:

12kmTransmission:

221

km

Distribution:

8,984

km

Others:－km

・Cast iron: 6,381km
Type of material: ・Steel: 481km
・Stainless: 14km

Others・Number of employees: 623
・Seismic reinforcement rate of pumping stations: 4.8%
・Seismic reinformcement rate of distribtuion reservoirs: 21.6%
Other information:
・Maximum daily supply: 1.04 million m3/day
・Maxiumum facility utilization rate: 68.5% (Maximum daily supply/treatment capacity)
・Facility utilization rate: 62.9% (Average daily water supply/treatment capacity)

・The informaiton in the Basics, Facilities and Pipes sections (except for the pipeline length,
pipe material and ratio of lead service pipe) was cited from the Annual Statistics Report
FY2014 of the Kanagawa Prefectural Government.
http://www.pref.kanagawa.jp/uploaded/attachment/801189.pdf
・The pipeline length and pipe material is based on the registry of the fixed assets of theRemarks: Kanagawa Prefectural Government.
・The information on the lead service pipe and the seismic reinforcement ratio (except for theone of primary mains) was cited from the PI guidelines for water supply services FY2014.
http://www.pref.kanagawa.jp/uploaded/life/1005094_3294728_misc.pdf
・The seismic reinforment ratio of primary mains is based on the reference material below.
http://www.pref.kanagawa.jp/uploaded/attachment/832973.pdf

2Water Utility Information (FY 2014)

No.2-2
Tanigahara
WTP

No.2-3
Oyama WTP

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No.2-5
Kissawa water
sourceNo.2-1Samukawa
WTP
No.2-4
Midono water
sourceService area
Case study facility

3

Itarih
WTP

Midonowater source

Shinanoki
WTP

Oyama WTP

Toya WTP

NaganoWTP

Kissawa
water source

Samukawa WTP

Tanigahara WTPof

Ochiai
WTP

Wada WTP
Sokozawa
WTP

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Kamasawa WTP

O
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Case Study Report (Samukawa Water Treatment Plant)
Case #2-1
Samukawa Water Treatment Plant
Key word: Surface water (river), Rapid filtration

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Outline:<Characteristics>●Features of the Samukawa Water Treatment Plant
・Reliable water supply: The Samukawa Water Treatment Plant has a distribution
management system to monitor and control reservoirs and pumping stations in theutility's distribution network. On the premises there are two water treatment plants called
No. 2 and No 3 WTPs (No. 1 WTP has been demolished). These two plants are responsible
for an efficient and reliable distribution management based on demand forecasts as well
as for mutual water transfers with other utilities.
・Environmental measures: Solar power generation system. Surplus soil from on-site
excavations is recycled as raw materials of cement additives.
・Private sector involvement: A Private Finance Initiative (PFI) has been used for theconstruction and operation of the drainage facility.
<Outline>
・The Samukawa Water Treatment Plant is situated in the Samukawa Town
approximately 6.5 km upstream from the estuary of the Sagami River. The Samukawa
intake weir located in the town abstracts water from the river. The water treatment
process consists of a coagulation/sedimentation, filtartion and disinfection.
・Service area: 11 Cities and 4 Towns
・Capacity: 750,000 m3/d (No. 2 WTP: 210,000 m3/d + No. 3 WTP: 540,000 m3/d)

Address:

Miyagawa 4271, Samukawa Town, Kanagawa Prefecture

Land area:

487,229m2

Water
treatment
process:

Coagulation/sedimentation + Rapid filtration + Chlorine disinfection

Capacity

750,000 m3/d

Water source: Surface water (Sagami River)■Since the raw water is taken from downstream of the Sagami River, it tends to be
adversely affected by phytoplankton growth and aritificial contaminations in upstream
river bodies and lakes.
Raw water
quality:

Chemical doseStart ofoperation:<Average raw water quality in FY2014 (maximum)>・Turbidity: 9.1 degrees (51 degrees) ・Hardness: 59 mg/L (68mg/L) ・TOC: 0.8 mg/L
(1.3 mg/L)
・ｐH: 7.8 (7.9) ・Color: 3.4 degrees (12 degrees) ・Geosmin: 0.002μg/L (0.004μg/L)
・2-MIB: <0.002 μg/L (0.007 μg/L) ・TON: 8（17）Sulfuric acid (pH adjustment), Sodium hydroxide (alkalinity adjustment),
Polyaluminum chloride (coagulation), Sodium hypochlorite (disinfection)

Dec-635

Sandsettlingbasin

Powdered activatedcarbonJunctionwell

3rd Water Treatment Plant

Sagami
Sagami
River
River

Sand
settlingbasin

Intakepump

Pre-PACl

Rapid
mixingsodium hydroxide

sodium hypochlorite

Polyaluminum chloride

Receiving
well andrapid
mixingReceiving
well

Flocculation

Flocculation

Water
treatment
process
Polyaluminum chloride

sodium hypochlorite

sodium hypochlorite

Clear water
storage

Secondary
Chlorination

Clear water
storagesodium hydroxide

Filtration

Sedimentat
ion(inclined
plate)

Filtration

Secondary
ChlorinationPre-chlorination

Filtration
receivingwell

sodium hypochlorite

sodium hydroxide

Pre-chlorination

Sedimentat
ion(horizontal)

sodium hypochlorite

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Sulfuric acidIntake
pump

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sodium hydroxide

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2nd Water Treatment Plant

Case Study Report (Samukawa Water Treatment Plant)●Arial view

Layout:6

Case Study Report (Samukawa Water Treatment Plant)

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●Sand settling basin●Flocculation basin●Sedimentation basin

Pictures:●Rapid filtration basin

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●Intake point●Solar Power Generation System for CO2 reduction
Maximum output: 120 kw (daily output varies depending on the weather)
Installation: Feb 2005
Location: on the top cover of filtration basins

Otherfacilities:●Backup Power Supply System
The backup power supply system enables the No. 2 and No. 3 water treatment plants tocontinue operation when a blackout cuts the commercial power supply from the Tokyo
Electric Power Company.
Other information
・The Brochure of the Samukawa Water Treatment Plant (June 2015)
・The Water Quality Report of the Kanawaga Prefectural Government's Water Supply Service (Jan 2016)7

Case Study Report (Tanigahara Water Treatment Plant)
Case #2-2
Tanigahara Water Treatment Plant
Key word: Surface water (lake), Slow filtration

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Outline:<Characteristics>
・Efficient and Reliable water supply: The Tanigahara Water Treatment Plant has amonitoring and control system for not only on-site facilities but outside reservoirs andpumping stations of the utilty's distribtuion network, providing an efficient and reliable
water supply. To improve the treated water quality, automated feeders of activated carbon
were instlalled in 2010.
・Multiple water treament processes: the plant has two trains of water treament processes
with the one using slow filtration and the other rapid filtration. The latter has three typesof sedimentation methods: horizontal, inclined plate, and rapid ones.
・Environmental measures: Surplus soil from on-site excavations is recycled as raw
materials of cement additives<Outline>
・Built in 1942 to address a rapid increse in water demand in the Sagamihara Region.
・Service area: 2 Cities and 1 Town
・Capacity: 242,800 m3/d (slow filtartion system: 32,800 m3/d + rapid filtration system:
210,000 m3/d)

Address:

Tanigahara 2-6-1, Midori-ku, Sagamihara City, Kanagawa Prefecture

Land area:

91,492m2

Water
treatment
process:

1. Slow filtration system: Sedimetation + Slow filtration + Chlorine disinfection
2. Rapid filtration system: Coagulation/sedimentation + Rapid filtration + Chlorine
disinfection

Capacity

242,800 m3/d

Water source: Surface water, Subsoil water (Sagami River)■Mostly abstracted from the Sagami Lake, the raw water tends to contain a range ofphytoplanktons including synedra (clogging filtration basin), mycrocystis (affecting
filtrate turbidity) and anabaena (musty odor).
Raw water
quality:

Chemical dose:Start ofopeation<Average raw water quality in FY2014 (maximum)>・Turbidity: 7.6 degrees (35 degrees) ・Hardness: 53 mg/L (61 mg/L) ・TOC: 0.8 mg/L
(1.3 mg/Ｌ)
・ｐH: 7.8 (8.5) ・Color: 6 degrees (22 degrees) ・Geosmin: 0.003μg/L (0.008μg/L)
・2-MIB: <0.001 μg/L (0.002 μg/L) ・TON: 3 （5）Sulfuric acid (pH adjustment), Calcium hydroxide (alkalinity adjustment),
Polyaluminum chloride (coagulation), Sodium hypochlorite (disinfection)

Mar-408Case Study Report (Tanigahara Water Treatment Plant)●Arial view

LayoutPowdered activated carbon & Calcium hydroxide
Sodium hypochlorite

Concentrated sulfuric acid

PACl

Sodium hypochlorite

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FlocculationSagami
Sagami
Lake
River
&
Wakui
Lake

Sand
Settling
Basin

Continuous

Sedimentat
ion(inclined
plate)

Rapid
sedimentati
on

As necessary

Rapidfiltration(140 m/d)

Clear
water
storage

PACl
Flocculatio
n
PACl

Water
treatment
process flow

Sedimentat
ion(horizontal)

Rapid filtration typeContinuous
PACl

Sagami
Lake
&
Wakui
Lake

Receivingwell

As necessary
Sodium hypochlorite

FlocculationSedimentat
ion

Slow
filtration(4 m/d)

Clear
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storageSlow filtration type9

Case Study Report (Tanigahara Water Treatment Plant)●Intake point

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●Sedimentation basin(slow filtration system)●Coagulation/sedimentation basin●Coagulation/sedimentation basin(rapid filtraion system - horizontal)(rapid filtraion system)●Slow filtration basin●Rapid filtration basin

Pictures

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●Backup Power Supply System
In the event of a blackout cuts the commercial power supply, a backup
power generator enables the operation for up to one fourth of the total
plant capacity.
Otherfacilities:

Other information
・The Brochure of the Tanigahara Water Treatment Plant (March 201)
・ The Water Quality of the Kanawaga Prefectural Government's Water Supply Service(Jan 2016)10

Case Study Report (Oyama Water Treatment Plant)
Case #2-3
Oyama Water Treatment Plant
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Key word: Membrane filtration, surface water (river)

Outline:<Characteristics>
・Demand fluctuation management: Situated in a tourist zone, the Oyama Water
Treatment Plant has relatively broad water demand fluctuations throughout the year but
has been producing drinking water in a safe and reliable manner.
<Outline>・With a capacity of 740 m3/d, it abstracts water from the Oyama River and suppies about
270 households in the Oyama and Koyasu Districts.
・Service area: portions of 1 City

Address:

Sakamoto 671, Oyama, Isehara City, Kanagawa Prefecture

Land area:

592m2

Treatment
process:

Sedimentation + Membrane filtration + Chlorine disinfection

Capacity

1,000 m3/d

Water source: Surface water (Oyama River)■Abstracted from a mountaineous region, the raw water has a high quality with little
artificial contaminations.
Raw water
quality:<Average raw water quality in FY2014 (maximum)>・Turbidity: 0.6 degrees (2.3 degrees) ・Hardness: 36 mg/L (38 mg/L) ・TOC: 0.5 mg/L
(1.7 mg/L)
・ｐH: 7.6 (7.7) ・Color: 2.1 degrees (6.4 degrees) ・Geosmin: <0.001μg/L (-)
・2-MIB: <0.001 μg/L (-) ・TON: 3 (5)Chemical dose: Sodium hypochlorite (disinfection)
Start ofoperation:

April 1986 (membrane filtration since 1998)

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Water flow meter

Turbidity meter

Advanced turbidity meter

Thermometer

Residual chlorine meter

Differential pressure gauge

Water level gauge

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Th

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Pr

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Intake

M

Oyama
River

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Junction
well

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M S

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Membrane filtration

Pr

Wash
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Clear
water
storage

L R S

Sediment
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basin

Intakemeasuring basinSand
settling
basin

Raw
water
tank

Th

L

M

L

M

DrainagetankReservoir

Receivingtank

Customertap

Customertap

Discharge

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backwash pumpfor dust remover

Dust
remover

Receiving
well

Treatment
process flow
diagram:

M Th T

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Sodium hypochlorite

Customertap

Case Study Report (Oyama Water Treatment Plant)●Outside appearance

Layout12

Case Study Report (Oyama Water Treatment Plant)

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●Intake point●Intake point●Settling basin, Sedimentation●Settling basin, Sedimentation

basin (when covered)basin (when opened)●Membrane filtration system●Membrane filtration system

Pictures

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Other
facilities:●Membrane module
12 m3 x 34 modules x 3 trains (102 modules in total)
Filtration method: external pressure type dead-end filtration
Filtration velocity: 1.0 m3/m2*d (maximum)
Modle size: φ114×1,078 mm

Other information
・The Brochure of the Oyama Water Treatment Plant (June 2010)
・The Water Quality Report of the Kanawaga Prefectural Government's Water Supply Service (Jan 2016)13

Case Study Report (Midono Water Source)
Case #2-4

Midono Water Source

Key word: UV treatment system, Spring water

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Outline:Address:<Chracteristics>
・Environmental measures: Because of a very high raw water quality throughout the year,
a UV treatment system has been adopted, saving energy required for water treatment.
・Service area: portions of 1 Town
・Design capacity: 12,800 m3/d

Sengokuhara Daigatake 1277-2, Hakone Town, Kanagawa Prefecture (location of the UV
treatment system)

Land area: 16,127m2
Water
treatment UV treatment + Chlorine disinfection
process:
Capacity: 12,800 m3/d
Water source: Spring water

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■Although influenced by volcanic soil, the raw water has a very high quality with little
contaminations.
Raw water <Average raw water quality in FY2014 (maximum)>quality: ・Turbidity: <0.1 degrees (<0.1 degrees) ・Hardness: 110 mg/L (110 mg/L) ・TOC: <0.1
mg/L (0.1 mg/L)
・ｐH: 7.2 (7.2) ・Geosmin: <0.001μg/L (-)
・2-MIB: <0.001 μg/L (-) ・TON: <1 (<1)
ChemicalSodium hypochlorite (disinfection)
dose:
Start ofMar-68operation:

14

Case Study Report (Midono Water Source)●Midono Water Source

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Layout

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Motor operated valve

Emergency stop valve
Sodiumhypochlorite

No. 1 UV treatment system

Treatment
process flow
diagram:To
anotherpumping
stationNo. 1 Receiving well
Strainer

Motor operated valve

Emergency stop valve
Sodiumhypochlorite

Pumping station
Distribution

No. 2 UV treatment system
Midono water source

No. 2 Receiving well

Reservoir

15

Case Study Report (Midono Water Source)

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●Intake facility●Intake facility●Spring water●UV system (outside)(inside the intake facility)

Pictures:●UV system

Otherfaciliteis:●UV system structure●UV treatment system
Irradiation dose: over 10mJ/cm2
Size of irradiation tank: φ500 mm x 2400 mm
Number of UV lamps: 6 lamps/unit
Size of a UV lamp: φ19 mm x 1500 mm

Other information
・The Brochure of the Kanagawa Prefectural Government's Water Service in the Hakone Town (Apr 2014)
・The Water Quality Report of the Kanawaga Prefectural Government's Water Supply Service (Jan 2016)16

Case #2-5

Case Study Report (Kissawa Water Source)
Kissawa Water Source

Key word: Ground water, Chlorine disinfection only

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<Characteristics>
・Safe and refreshing drinking water: the ground water has a very good quality throughout
the year.
Outline:<Outline>
・Service area: the ground water is used to suppliment reservoirs of other water treatment
plants.
・Maximum capacity: 1,100 m3/d
1st well: φ75×60ｍ
2nd well: φ125 x 12 m、φ100 x 48 m

Address:

Tsuchiya 1760, Hiratsuka City, Kanagawa Prefecture

Land area:

322m2

Water
treatment
process:

Chlorine disinfection

Capacity:

1,100 m3/d

Water source: Ground water■The raw water has a very high quality with little contaminaions.

Raw water
quality:<Average raw water quality in FY2014 (maximum)>・Turbidity: <0.1 degrees (<0.1 degrees) ・Hardness: 140 mg/L (140 mg/L) ・TOC: 0.2
mg/L (0.3 mg/L)
・ｐH: 7.6 (7.9) ・Geosmin: <0.001μg/L (-)
・2-MIB: <0.001 μg/L (-)

Chemicaldose:

Sodium hypochlorite (disinfection)

Start ofoperation:

Unknown17

Case Study Report (Kissawa Water Source)
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●Overview

Layout:

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Residual chlorine meter

Customertap

R
Sodiumhypochlorite

Treatment
process flow
diagram:

Well

Well

P

M

Pump Water
meter

Reservoir

Reservoir

Customertap

Receivingtank

Customertap

18

Case Study Report (Kissawa Water Source)●Well (outside)●Well (inside)●Intake facility●Pumping facility

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Pictures

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・The Water Quality Report of the Kanawaga Prefectural Government's Water Supply Service (Jan 2016)19

Water Utility Information (FY 2014)
Name of utility: Osaka Water Supply Authority

Service type:

Wholesale water supply

Administrative
population*1:

6.2 million people

Start of service*2:

Population
served*1:

6.1 million people

Service area*3:1100.46

Household use

ー

m3/d

Commercial
andinstitutional
use:

ー

m3/d

Others:ーm3/dWholesale watersupply1.4 million

m3/dService coverage:

ー

%

2011
km2

Volume of water supply

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Average dailywater supply:

1.4 million

m3/d

Break
down

Average dailywater supply perperson*4:

252.3

L/person/dEffectiveness:

100.0

%

Revenue water:

100.0

%

NRW:

0.0

%

Water loss

0.0%

Note: as a wholesale supplier, service coverage is not applicable. NRW and water loss are both 0%.
Water ratesーWater rates for 10m3/month:
Water production
cost:

64.35

yen/m3

Water supply cost:(including taxes)

yen

75

yen/m31

Water Utility Information (FY 2014)
Name

Capacity

Murano WTP

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Water Treatment
Plants:Niwakubo WTP

Mishima WTP

Pipeline length:Type of material:573.19203,000

330,000

m /d

m3/d

m3/d

Treatment process

Surface water

Coagulation/sedimentation + Rapid
filtration + Ozone + Granular
activated carbon + Chlorine
disinfection

Surface water

Coagulation/sedimentation (only inthe event of high turbidity events) +Biological treatment (contact
filtration) + 2nd coagulation +Rapid filtration + Ozone + Granular
activated carbon + Chlorine
disinfection

Surface water

Biological treatment (honeycombtube) + Coagulation/sedimentation+ Rapid filtration + Ozone +Granular activated carbon +Chlorine disinfection

2,330,000 m3/d

Total

P
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1,797,000

3Water sourcekm

Conveyance:

16.698km

Transmission:

549.363km

Distribution
:

0

km

Others:7.129

km・Cast iron 35.560 km ・Ductile iron 435.630 km
・Steel 101.999 km ・Stainless 0.025 km

・Number of employees: 376
・Seismic reinforcement rate of pumping stations: 100%・Seismic reinforcement rate of distribtuion reservoirs: 10.4%
Other information:
・Maximum daily supply: 1.56 million m3
・Maxiumum facility utilization rate: 66.9% (Maximum daily supply/treatment capacity)
・Facility utilization rate: 60.7% (Average daily water supply/treatment capacity)

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●Primary reference materials
・Osaka Prefectural Government. Water Supply Service in the Osaka Prefecture in FY2014.
http://www.pref.osaka.lg.jp/kankyoeisei/suido/genkyo-26.html
・Osaka Water Supply Authority. Water Suply Statistics Annual Report FY2014. http://www.wsaosaka.jp/siryoushu/toukei-nepo/26toukei_index.html
Remarks: *1 The administrative population and the population served are those of the 42 municipalities in the
Osaka Prefecture (excluding the Osaka City) in FY2014.
*2 The water supply department of the Osake Prefectural Government (the predecessor of the Osaka
Wate Supply Authority) was created in 1940 and began water supply in 1951.
*3 Of the 42 municipalities in the Osaka Prefecture (excluding the Osaka City) in FY2013.
*4 Of the 42 municipalities in the Osaka Prefecture (excluding the Osaka City) in FY2012.
*5 The water treatment plants for industrial users are not listed here.

2

Water Utility Information (FY 2014)

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Supplying wholesale waterto all the municipalities in
the Osaka Prefecture
excluding the Osaka City

No.3
Murano WTP

Service area
Case study facility3Case Study Report (Murano Water Treatment Plant)

Case #3
Key word:

Murano Water Treatment Plant
Advanced water treatment (ozone + granular activated carbon), Multi-story water
treatment facility, Water pressure differential power generation, Surface water (river)<Outline>
・The Murano Water Treatment Plant is responsible for approximately 80% of the utility's
water production.
・Ozonation and granular acivated carbon (GAC) treatment was installed in 1998 toaddress issues of musty odor and trihalomethane.

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<Characteristics>
・One of the largest water treatment plants in Japan in terms of capacity
・One of the first water treatment plants in Japan that adopted ozone and GAC
・A very rare, multi-story water treatment facility

Outline:<Multi-story water treatment facility>
・The multi-story water treatment facility contains the equipments for sedimentation,
filtration, ozonation, GAC treatment etc. These equipments are located on the multiple
stories of two connected buildings. Each building has a capacity of 275,000 m3/d. The
operation started in July 1980. (The advanced water treatment process was installed in
1994 in the multi-story water treatment facility.)
・When a water demand increase in the 1970s required an enhancement of the utility's
water supply capacity, there was not enough available area on the premises to build a new
facility. The utility thought it better, however, if a new facility could use some of theexisting Murano facilities so they wouldn't have to build new ones. Their answer was themulti-story water treatment facility that requires much smaller site space and thus allows
for more efficient daily inspections and repair work of the equipments.
・The facility has a pressure differential power generation system. Using a 10-meter
difference in water levels among basins, it provides a maximum electricity of 240 kw. The
accumulated electricity in 2014 was 1.41 million kWh.

Address:

Murano Takamidai 7-2, Hirakata City, Osaka Prefecture

Land area:

317,756 m2

Water
treatment
process:

Coagulation/sedimentation + Rapid filtration + Ozone + GAC + Chlorine disinfection

Capacity:

1,797,000 m3/d

Water source: Surface water (Yodo River)Raw water
quality:■Since the plant abstracts water from the downstream of the Yodo River, the raw water
is affected by the use in the upstream side of the river. It used to contain much ammonia
nitrogen but its concentration has decreased to a non-significant level in recent years due
to a development of sewage infrastructure.
■Because of an influence from the Lake Biwa situated upstream of the Yodo River, theraw water tends to be adversely affected by musty odor, picoplankton growth, and algae
growth during summer that increase the pH.
<Average raw water quality in FY2014 (maximum)>・Turbidity: 8 degrees (62 degrees) ・Hardness: 42.6 mg/L (45.1 mg/L) ・TOC: 1.8 mg/L
(2.4 mg/L)
・ｐH: 7.4 (7.8) ・Color: 20 degrees (190 degrees) ・Geosmin: 0.001 μg/L (0.004 μg/L)
・2-MIB: 0.004 μg/L (0.014 μg/L) ・TON: 24（30）Chemicaldose:

Sulfuric acid (pH adjustment), Sodium hydroxide (pH adjustment),
Polyaluminum chloride (coagulation), Sodium hypochlorite (disinfection)

Start ofservice

1963/7/1

4Case Study Report (Murano Water Treatment Plant)●Aerial view

Layout

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Treatment
process flow
diagram:●The multi-strory water treatment facility has 72.3 m in length, 88.8 m in depth and 31.1
m in height.

Sectioned diagram of the multi-stroy
water treatment facility

Sand filtration

Pictures

Pipingcorridor
Pipingcorridor

GAC
filtration
basin
Ozone
generator

Pipingcorridor

Sedimentation

Pipingcorridor

Receivingdock

GAC
storage

Electricalroom(ER)ER

Pipingcorridor

Sand filtration

Pipingcorridor

Pipingcorridor

GAC filtration basin

Clear water storage
Flocculation basin

ER

Sludge drainage

ER
Storageroom

Pipingcorridor

Sedimentation

Sludge drainage

5

Case Study Report (Murano Water Treatment Plant)● A solar power generation system: installed on the top cover of sedimentation basins.
The cover also helps prevent algae growth. The maximum output is 360 kW.
● A pressure differential power generation system: the multi-strory water treatment
facility generates power by utilizing the difference in water pressure between the chlorine
mixiging basin and the treated water reservoir.

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Rapid filtraion

Ozone

Other
facilities:

Coagulation/
Sedimentation

Chlorine
mixing basin

GAC

Multi-story water treatment facilityGtreatedwater
reservoir

Pressure differential
power generation system●Organic compound sensors in the intake station continuously monitor volatile organic
compounds in the raw water.
●Carp Sensor is also installed in the intake station for continuous monitoring of the raw
water quality.

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ct:
o
Expenses: Unknownce Other information
Reference:s
Osaka Water Supply Authority. Commemorative Publication for the Establishement of the Osaka Water
Supply Authority. http://www.wsa-osaka.jp/event-pr/pamphlet/s6

Water Utility Information (FY 2014)
Name of utility:

Water and Sewer Bureau of theCity of Kitakyushu

Service type:

Wholesale and retail watersupplyAdministrative
population:

957,000

Start of service:

1907

Population served:

995,000

Service area:

270.16

Household use

213

m3/d

Commercial
andinstitutional
use:

61

m3/d

Others:1.3

m3/d

Wholesale watersupply12m3/dService coverage:

99.6

%

km2

Water supply volume

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Average dailywater supply:

m3/d

310,000

Break
down

Average dailywater supply percapita:311

L/person/dEffectiveness:

93.11

%

Revenue water:

90.4

%

NRW:

2.69

%

Water loss

6.66

%

Water rates
842 / 780

*Calculation condition: The fixed charge is 680 yen.
The volumetric charge is 10 yen/m3. In case of service
pipe of 13-mm diameter.

Water rates for 10m3/month:

Water production
cost:

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water for wholesalei
supply):
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Pipieline length:yen/m3145.21Name

Water supply cost:

Capacity

Treatment
process
Coagulation/sedimentation + Rapid
filtration

255,200m3/dDam, subsoil
water, surface
water

Dobaru WTP

7,800

m3/d

Dam

Hata WTP

24,000m3/d

Dam

Ano WTP

300,000m3/dDam, surface
water

Honjo WTP

141,000m3/dDam, surface
water

Total

728,000m3/d

km

yen/m3144.65Water
sourceIdeura WTP

4,518.2(including
taxes/excluding

yen

Slow filtration
Coagulation/sedimentation + Rapid
filtration
Biological contact filtration +Coagulation/sedimentation + Rapid
filtration
Biological contact filtration +Coagulation/sedimentation + Rapid
filtration

Conveyance:

188.6

km

Transmission:

Distribution:

4,098.6km

Others:

230.8

km

ー

km

・Ductile iron 3950.6 km
・Cast iron 265.7 km
Type of material:
・Steel 98.8 km
・Others (GP, VLP, etc) 156.4 km
・Number of employees: 379
・Maximum daily supply: 340,000 m3
Other information:
・Maxiumum facility utilization rate: 44.4% (Maximum daily supply/treatment capacity)
・Facility utilization rate: 40.2% (Average daily water supply/treatment capacity)
Remarks:●Kitakyushu City Water and Sewer Bureau. Outline of the Water and Sewer Services:
https://www.city.kitakyushu.lg.jp/suidou/s00101009.html

1Water Utility Information (FY 2014)

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No.4
Ano WTP
穴生浄水場

Service area
Case study facility2Case #4

Key word:

Case Study Report
Ano Water Treatment Plant (Upward Biological Contact
Filtration: U-BCF)
Advanced water treatment, Upward Biological Contact Filtration,Taste and Odor, Surface
water (dam)<Characteristics>
1. Features of U-BCF
The Upward Biological Contact Filtration (U-BCF) system can remove ammonia nitrogen, dissolved
manganese, and musty odor causing substances like geosmin efficiently. Using the U-BCF helped
reduce the chemical dose at the Ano Water Treatment Plant.
2. U-BCF in other countries
The Haiphong Water Supply One Member Company Limited , the water utility in Haiphong City in
Vietnam, has installed a U-BCF system in their Vinh Bao Water Treatment Plant.

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<Outline>
・As the utility's primary water treatment plant, the Ano Water Treatment Plant has the capacity of
300,000 m3/d (39% of the total production).
・The U-BCF was developed by the utility itself. It was first installed in 2003.

Outline:<Characteristics of U-BCF>
・The core function of the U-BCF is to artificially reproduce a natural environment in which aquatic
microorganisms decompose micropollutants in a more efficient manner.
・The filter mediaum is granular activated carbon.
・Due to its porus, rugged, uneven surfaces, the granular activated carbon provides a much better
environment than, for example pebbles in a riverbed for microorganizams to live in.
・An upward water flow through the activated carbon layers makes the raw water contact withmicroorganisms.
・The upward water flow stirs the granuler activated carbon, contributing to an improved biologicalcontact.
・When the U-BCF was installed at the Ano Water Treatment Plant, it was placed before the receiving
well.
Enalarged view of the filter media
GAC

Pollutant

Microorganism

Water flow

Dissolve

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Dissolve
Dissolve
Dissolve
Dissolve

Activatedcarbon layer

Dissolve

Dissolve

Dissolve

U-BCF Facility

U-BCF Facility

Conventional
MixingRaw
water

Sedimentation
Filtration
Distribution3

Case Study Report
Address: Takanosu 3-10-16, Yahata-Nishi Ku, Kita-Kyushu City, Fukuoka Prefecture
Land area: 84,150m2
Water
treatment U-BCF + Coagulation/sedimentation + Rapid filtration
process:
Water source: Surface wtaer (river/dam)■The raw water contains much musty odor substances, ammonia nitrogen andmanganeze.

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<Average raw water quality in FY2014 (maximum)>Raw water ・Turbidity: 14 degrees (44 degrees) ・Color: 16 degrees (48 degrees) ・pH: 7.6 (7.8)
quality: ・Hardness: 66 mg/L (102 mg/L) ・TOC: 1.8 mg/L (2.7 mg/L)・Ammonia nitrogen: 0.02 mg/L (0.09 mg/L)
・Dissolved manganeze: 0.007 mg/L (0.033 mg/L)
・Geosmin: 0.002 μg/L (0.006 μg/L)
・2-Methylisoborneol (2-MIB): 0.001 μg/L (0.002 μg/L)

Chemicaldose:

As for the U-BCF, it requires no chemical dose.

Capacity: 171,000 m3/d

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Start of The U-BCF started operation in 2003 in the Ano Water Treatment Plant (in 2000 in theoperation: Honjo Water Treatment Plant).

穴生浄水場

Water
supplynetwork,
City of
Kitakyushu

facilities under construction
Onga river system
Other 3 rivers system
Intake facility
Wate storage
WTP
Pumping station
Distribution reservoir
Distribution reservoir (solar
power)

4

RiverControl center

Intake pump

Drainage Process

Sun drying

Drainage basin

Rapid mixing

Thickening

Pressure
dewatering

Cake yard

Clear water storage

Wash water tank・Tertiary Sodium hypochlorite
・ Sodium hydroxide

Filtration

Sedimentation

Sludge basin

Floc.

Secondary Sodium
hypochlorite

Treatment
process flow
diagram:

U-BCF

・Carbon dioxide gas
・Pre- sodium hypochlorite
・ Polyaluminum chloride・ Aluminum sulfate

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Treatment Process

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Hydroelectricity

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Dam

・Ground・Seedings
・Cement
・Improved soil

Utilizing
cakes

Reservoir

Case Study Report5Case Study Report
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Pictures

Ano Water Treatment Plant
Other
facilities:

Small-size hydropower generation system

Order/
contract:

Tendering

Expenses:

Unknown

Upward Biological Contact
Filtration (U-BCF)

Other information:ー6Water Utility Information (as of 2016)
Name of utility:

Bureau of Waterworks Tokyo
Metropolitan Government

Service type:

Wholesale + Retail water supply

Administrative
population:

13.74 million people

Start of service:

1898

Population served:

9.37.5 million people

Service area:

2626.79km

Household2.96 million

m /dIndustrial

37,000

m /d

Urban

1.11 million

m /dVolume of water supply

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Average dailywater supply:

4.11 million

Break
down

3

m /d

3
3
3

Average dailywater supply
per person:-

L/person/dService coverage:100%

Effectiveness:

96.7

%

Revenue water:

96.0

%

NRW:

4.0

%

Water loss

3.1%

Water rates

1,047/970**Calculation condition: the fixed charge is 860 yen and thevolumetric charge is 0 yen for 13 mm at 1-5 m3 use and 22 yen/m3
at 6-10 m3 use.

Water rates for 10 m3/month:

Water production
cost:

208.95yen (with taxes/without taxes)

3

yen/m

Water supply cost:

211.61

3

yen/m

1

Water Utility Information (as of 2016)

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Water Treatment
Plants:(including the water
received for wholesale
supply)Name

Capacity

Kanamachi WTP

1,500,000 m3/dTone River・
Arakawa River

Rapid filtration・Advanced water

Misato WTP

1,100,000

m3/dTone River・
Arakawa River

Rapid filtration・Advanced water

Asaka WTP

1,700,000

m3/dTone River・
Arakawa River

Rapid filtration・Advanced water

Mikuni WTP

300,000

m3/d

Tone River・
Arakawa River

Rapid filtration・Advanced water

Water source

Treatment process

treatment (applied entirely)

treatment (applied entirely)

treatment (applied entirely)

treatment (applied entirely)
Rapid filtration・Advanced water

Higashimurayama
WTP

1,265,000

m3/dTone River・
Arakawa River・
Tamagawa River

Ozaku WTP

280,000

m3/d

Tamagawa River

Rapid filtration

Sakai WTP

315,000

m3/d

Tamagawa River

Slow filtration

Kinuta WTP

114,500

m3/d

Tamagawa River

Kinutashimo WTP

70,000m3/dTamagawa River

Tamagawa WTP(152,500)

m3/d

Tamagawa River*operation suspended due to raw
water degradation

Nagasawa WTP

200,000

m3/d

Sagamihara water

Rapid filtration

Suginami WTP

15,000m3/dGround water

Disinfection only

Total

6,859,500

treatment (applied partially for
880,000 m3/d of Tone River・
Arakawa River waters)

Membrane filtration・
Slow filtration
Membrane filtration・
Slow filtration
Slow filtration・Rapid filtration

P
i
p
e
s

O
t
h
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s

Pipeline length:

27,792m3/dConveyance:-

km

Transmission:-

km

Distribution:

27,038km

Others:-km

km

Type of material:

・Cast iron・Steel・Others

Other information:

・Number of employees: 3,800 (as of August 1 2017)
・Maximum daily supply: 4.51 million m3/d・Facility utilization rate: 78.6% (maximum daily supply/facility capacity)

Remarks:・ "Overview of the Water Services." Bureau of Waterworks Tokyo Metropolitan
Government. https://www.waterworks.metro.tokyo.jp/

2

Case Study Report (Asaka Water Treatment Plant)

Case #5
Key word:

Asaka Water Treatment Plant
Advanced water treatment; raw water accommodation pipeline; solar power generation<Characteristics>
1. Installation of advanced water treatment process
Following the Kanamachi Water Treatment Plant (WTP) and the Misato WTP, theBureau installed an advanced water treatment using ozonation and biological activatedcarbon process at the Asaka WTP in November 2004. Together with the second-phasefacilities completed in March 2014, the advanced treatment now accounts for Asaka’s
entire water treatment of 1.7 million m3/d. This also means that all the water abstracted
from the Tone River and its tributaries are now being treated through the advanced
treatment at various WTPs of the Bureau including the Asaka.

W
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T
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t

Outline:

P
r
o
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2.

Mutual accommodation of raw water
The Asaka WTP has been connected with the Higashimurayama WTP by a raw wateraccommodation pipeline. This allows the Asaka to use the Tama River’s water whenneeded, in addition to the water from the Tone River and the Arakawa River.

3.

Use of PFI (public finance initiative)
Since April 2005, the Asaka has operated its power generation facility and sodium
hypochlorite production facility under PFI scheme.

<Advanced Water Treatment Process>• The advanced water treatment process consists of an ozonation and a biologicalactivated carbon absorption. It aims to reliably and efficiently remove substances thatcannot be adequately removed by the conventional water treatment processes such as
rapid filtration.
• The ozonation oxidizes and decomposes substances that can produce musty odor andtrihalomethanes.
• The biological activated carbon (BAC) adsorption removes pollutants throughactivated carbon adsorption and decomposition by microorganisms that grow on the
carbon.
• The Bureau has installed an “ozonation + BAC” before filtration so it comes in as the
final treatment process, as it can trap and remove microorganisms that may leak fromthe BAC layer. This decision was made based on the research and experiments
conducted for six years from 1983.
• In addition, the Asaka WTP also uses filtration before “ozone + BAC” in order toreduce trihalomethane precursors efficiently and to reduce the power consumption
required for ozone injection.
＜Raw water accommodation pipe>•••

The utility has installed a "raw water accommodation pipe" that allows raw water fromdifferent river systems to be mutually accommodated for efficient use of raw water.
Asaka normally abstracts from the Tone River system, but sending some of its water tothe Higashimurayama water treatment plant helps keep enough water stored all thetime from the Tama River system, including at the Ogouchi reservoir.
In the event of drought or water quality incidents in the Tone River system, raw waterfrom the Tama River system is used by receiving its water from the Higashimurayama
water treatment plant.

2

Land area:

228,206 m (excluding water drainage facility)

Water
treatment
process:

coagulation + sedimentation + ozonation + granular activated carbon + chlorine disinfection

Water source: Surface water (rivers)

4

•

•
•

Raw water
quality:

Because the intake point is located in the lower reaches of the Arakawa River, theconcentration is relatively high of water quality parameters that could affect thetreatment process, such as organic matters and ammonia nitrogen.
In recent years, the concentration of substances that can cause musty odor has been
relatively high due to the effects of algae attached to stones on the riverbed.
When the amount of water is short for distribution due to drought and other reasons,water is temporarily taken from the Arakawa Reservoir located right in front of theintake point. This water is susceptible to the water quality within the Arakawa
Reservoir (especially the substances that can cause musty odor).

<Average raw water quality in FY2018 (maximum)>
Turbidity: 12 degrees (740 degrees)
Color: 7 degrees (26 degrees)
TOC: 1.7 mg/L (2.5 mg/L)
Potassium permanganate consumption: 6.0 mg/L (34 mg/L)
Ammonia nitrogen: 0.10 mg/L (0.43 mg/L)
Iron: 0.43 mg/L (1.0 mg/L)
Manganese: 0.076 mg/L (0.099 mg/L)
Geosmin: 2 μg/L (20 μg/L)
2-MIB: 6μg/L (170 μg/L)

Chemicaldose:

sulfuric acid (pH adjustment), caustic soda (pH adjustment),polyaluminum chloride (flocculation), sodium hypochlorite (disinfection),
powdered activated carbon (odor removal)

Capacity:

1,700,000 m3/d

Start ofservice

October 19665

Case Study Report (Asaka Water Treatment Plant)

7

Treatment
flow
diagram:

8

9

10

11

12

7. Pre-filtration basin
Smaller flocs that cannot be removed in thesedimentation are filtered out using filter
sand.

1

2

3

4

1. Grit chamber
Sand and soils mixed in the abstracted
water are settled.

5

8. Ozone contact basin
Ozone decomposes substances that causemusty odor and trihalomethane.

6

4. Chemical mixing basin
Polyaluminum chloride (flocculant) is added tocollect and settle fine sand and soil mixed in
the water.

2. Water pump
Water is pumped into the receiving well.
3. Receiving well
Water pumped up by the water pump is
led to the flocculation basin.

5. Flocculation basin
Fine sand and soil mixed in the water are madeinto flocs that are easy to settle.
6. Sedimentation basin
While the water is slowly flowing, the flocs inthe water settle to the bottom to make thewater cleaner.

9. Biological activated carbon
adsorption basin
Activated carbon removes the substances
decomposed by ozone. Also, themicroorganisms grown on the activatedcarbon decompose ammonia and othersubstances.
10. Post-filtration basin
The water is filtered again to make it safe andtasty to drink.

13
14
11. Chemical mixing area
Sodium hypochlorite is mixed with the filteredwater for disinfection.
12. Water distribution reservoir
Clear water is stored.
13. Transmission and distribution pump
The water stored in the distribution reservoir issent out for distribution.
14. Control room
The room is used to monitor the dosage ofvarious chemicals and water quality.

<Solar power generation system>
Solar panels installed on the top of the filtration basin.
Capacity: 1,200 kW
Solar panels installed on the roof of the second-phasebuilding and on the top of distribution reservoirs.
Capacity: 500kW
2nd advanced building
Control
officeOtherfacilities:

Installed on
the top of
filtration
basin

Ozone contact basin

Order/
contract:-

Expenses:

Unknown

Biological activatedcarbon adsorption
basin

Installed on
the top of
distribution
reservoir

Filtration basin

Distribution
reservoir

Other information
https://www.waterworks.metro.tokyo.jp/suidojigyo/gaiyou/shisetsu.html

6

7

8

9

10

11

12

7. Pre-filtration basin
Smaller flocs that cannot be removed in thesedimentation are filtered out using filter
sand.

1

2

3

1. Grit chamber
Sand and soils mixed in the abstracted
water are settled.
2. Water pump
Water is pumped into the receiving well.
3. Receiving well
Water pumped up by the water pump is
led to the flocculation basin.

4

5

6

4. Chemical mixing basin
Polyaluminum chloride (flocculant) is added tocollect and settle fine sand and soil mixed in
the water.
5. Flocculation basin
Fine sand and soil mixed in the water are madeinto flocs that are easy to settle.
6. Sedimentation basin
While the water is slowly flowing, the flocs inthe water settle to the bottom to make thewater cleaner.

8. Ozone contact basin
Ozone decomposes substances that causemusty odor and trihalomethane.

9. Biological activated carbon
adsorption basin
Activated carbon removes the substances
decomposed by ozone. Also, themicroorganisms grown on the activatedcarbon decompose ammonia and othersubstances.
10. Post-filtration basin
The water is filtered again to make it safe andtasty to drink.

13
14
11. Chemical mixing area
Sodium hypochlorite is mixed with the filteredwater for disinfection.
12. Water distribution reservoir
Clear water is stored.
13. Transmission and distribution pump
The water stored in the distribution reservoir issent out for distribution.
14. Control room
The room is used to monitor the dosage ofvarious chemicals and water quality.

2nd advanced building
Control
officeInstalled on
the top of
filtration
basin

Ozone contact basin

Biological activatedcarbon adsorption
basin

Installed on
the top of
distribution
reservoir

Filtration basin

Distribution
reservoir