Measures to makeHorikawa River Limpid

Implementation by Nagoya City
Sep.28th 2019
Greenification & PublicWorks Bureau
River Plannning Div.
Waterworks and Sewerage Bureau
Sewerage Plannning Div.
Environment Bureau
Local environmental measures Div.
1

Implementation by
Greenification & PublicWorks Bureau

2◆Removal of Sludge①Sludge have been dredged on water route
between the Shiga Bridge and Shin-Horikawa
River confluence (1994-2007)②Construction of Bank Protection in River management project
Kurokawa Area

Nagoya Castle③After Bank Protection Works, River bed Excavation andremoval of sludge are implemented at the same timeThis project is going to be
carried out aroundGojo-Bridge area (2018-)
Nayabashi AreaOtoBridge・Sludge of 155,000m3 have been removed in the past
・The removing of sludge is continuing
around the Oto Bridge.

SumiyoshiBridge
Shin-Horikawa River
Confluence①
Dredging of Sludge on Water Route② Bank Protection Works③ River Bed Excavation andRemoval of Sludge at the same time3◆Ｃｏｎｓｔｒｕｃｔｉｏｎ of Shallows and Depths
Setting wooden piles and ripraps generates variable stream on the riverfor enforcing river’s self-purification function and creating habitats withgrowth of plants.

…fish spawning andplants’ seed ashore…change of stream
Construction in 2016
（Downstream of Meoto Bridge）

4

◆Construction of Shallows and Depths
City of Nagoya will constructed and installed shallows and Depths toupstream of Kizune-Bridge in Kita Ward in March 2019.

Horikawa River

Current condition

Kizune-Bridge
Area to be constructed

Chigonomiyajindo-Bridge

5◆Ｃｏｎｓｔｒｕｃｔｉｏｎ of Shallows and Depths
Installed in2010

Before (2009)

Installed in2012

After (2013)

Installed in 2015
(Downstream of Ruriko Bridge)

Before (2015）

After（2016）

Installed in2013

After (2013)

Before (2011)

After（2016）

Some of the creatures seen in the upstream of Horikawa River

Mallard

Pale chubJapanese mitten crab

Little egret

After (2015)

Installed in 2018
（upstream of Kizune-Bridge）

Installed in 2016
(Downstream of Meoto Bridge)

Before（2015）

Before (2012)

Before（2018）

After（2018）◆Improvement
・Variety and amount offish have increased.
（example pale chub)・Benthos have increased.
（example shrimp)
・Plants have grow up
more.

6

◆ Use of shallow groundwater①

2013.Mar.

②

2004.Oct.

Use of shallow groundwater in theupstream area of Horikawa River
Tsujie Bridge
0.01m3/s

Uprsteam of Seko Bridge0.01m3/s①★
②③④③⑤⑥ ★：2019⑦ (Upstream of Kurokawa⑤Sanage Bridge⑧Meijo Park

Nagoya castle

2005.Nov.

④Kizune Bridge
0.01m3/s

No.1 Bridge)

2015.Mar.

Shiga Bridge
0.01m3/s⑦2018.Mar.

Kinjo Bridge
0.01m3/s

2014.Mar.

Sanege Bridge
0.01m3/s⑥

2008.Mar.

Shimizu wakuwaku
0.0005m3/s
2016.Mar.

⑧Nakatsuchido Bridge
70.01m3/s

◆Cooperation with Cleaning group of ports(Sei-ko-kai,清港会)
HSC shares the information about the tide level and the place
which Dust is easy to collect with Sei-ko-kai, and they clean up
suspended garbage efficiently.

Condition of cleaning at high tide level time8

Implementation by
Waterworks and Sewerage Bureau

9Initiatives for clarification ofHorikawa river

10

Advanced water treatment■Initiatives for clarification of Meijo
water treatment center（disk filter）
Horikawa river Moriyama water
Advanced Facilities of simple
treatment
Meijo water treatment center

treatment center
Horikawa Ugan
Rain-water Reservior
Garbage Catcher

Meijo water
treatment
centerShiratoribashi
Pumping
stationOzone
Rain-water Reservior

Horikawa Sagan
Rain-water Reservior

Rain-water Reservior forpollution controllOzone Rain-water Reservior
Horikawa Ugan Rain-water Reservior
Horikawa Sagan Rain-water Reservior

Horikawa River

Shrinkage of Rainwater screen
slit

Nakajima pumping station

Chitosewater treatment
center(under installing)(under installing)

Shiratoribashi Pumping station
Nakajima pumping station
Chitose water treatment center

reclaimed wastewater supply
Moriyama water treatment center
The number ofGarbage Removal equipment

Total plan
127

Constructed112

Garbage Catcher

Future Plan1511

■Advanced water treatment◆Meijo Water Treatment Center（treatment capacity：50,000m3/day）
After installation

mg/lＳＳ

Significant
decrease3.3

Less than 1 Less than 1

1

Minute Suspended Solids(SS) in treated water
are removed more by the filtration devices
12■Advanced Facilities of simple treatment（Improvement of combined sewer system）
We changed the simple treatment of rain water from Settling treatment toFiltration treatment, remodeled the part of existing first settling basin andinstalled advanced facilities of simple treatment in the water treatment
centers.

◆ Meijo Water Treatment Center （treatment capacity：99,400m3/day）・Started operation in 2019

Treatment flow

Special filteration materilal※Left figure is Tenma Water Treatment Center◆Removal Rate of BOD ： 20%-30%➡ 50%-60% Improvement!

13

■Rain-water Reservior for pollution controll（Improvement of combined sewer system）
Construct rainwater storage facilities to reduce pollution load for
Horikawa River in rainy weather by storing high polluted first flush
rainwater temporarily.
Ozone
Rain-water Reservior

Horikawa Ugan
Rain-water Reservior

Started operation in 2006

Started operation in 2010 Started operation in 2019（12,000ｍ3）（13,000ｍ3）

Horikawa Sagan
Rain-water Reservior（14,000ｍ3）
14

■Removal and Reduction of inflow of pollutants◆Improvement of combined sewer system(Installation of Garbage Removal Device)

The number of installation ofGarbage Removal Device
Total plan

Installed by theend of 2018

Future plan toinstall127112

15

BeforeGarbage RemovalDevice
Overflow

Wastewater
Treatment Plant

Garbage in sewerage
overflows together
with rainwater

After

Wastewater
Treatment Plant

Overflow•Rainwater treated by thegarbage removal devices
overflow into river•Removed garbage is treated at
Wastewater Treatment Plant
together with sewerage

15

■Shrinkage of Rainwater screen slit
（ Improvement of combined sewer system ）Rainwater screens are the facilities to remove comparatively big garbage,and installed in water treatment centers and pumping stations.
Shrinkage of Rainwater screen slit remove more garbage.
・Shiratoribashi Pumping station
・Nakajima pumping station
・Chitose water treatment center◆Rainwater screen slit
４０mm → ２５mm
◆Reduction of inflow of pollutants

16

■Additional Water Resource
Conducting reclaimed wastewater treated bymembrane filtration
at the Moriyama Water Treatment CenterMoriyama
上下水道局WaterTreatment
Center
守山水処理センター

Water Supply： Up to 4,000m3/day（0.046m3/ｓ）

ShonaiIrrigation
庄内用水路

Flat membraneunit aerobic tank

Flat membrane unit

※Watering period is almost irrigation period（April～October）（Except the period for Shonai irrigation channel（November～March））

堀Horikawa
川 River

17

■Removal and reduction of inflow of pollutants◆Garbage catcher（Near Johoku Bridge) since 2006

garbage basket

Sanage Bridge
inflow gate

capturing fence

The exterior Garbage catcher

Meijo Park

Cross Section

Nagoya Castle
Koshio Bridge

Result of collection in 2015

1.4 t

Result of collection in 2016

1.3 t

Result of collection in 2017

0.7 t

Result of collection in 2018

1.1 t

Naya Bridge

18initiatives for clarification of
Shin-Horikawa river19

■initiatives for clarification of
Shin-Horikawa river
Horidome watertreatment
centerShin-Horikawa
River
Takakura
pumping station

Atsuta watertreatment center

Improving facilitys ofcombined sewer
system in Wakamiya
avenue Rain-waterReservior
Fukue Rain-waterReservior

Advanced Facilities ofsimple treatment
Horidome water treatment center
Tenmacho water treatment center
Rain-water Reservior forpollution controll
Wakamiya avenue Rain-water Reservior

Fukue Rain-water Reservior
Takatuzhi Rain-water Reservior

Takatuzhi Rainwater Reservior
Ushimakipumping stationTenmacho watertreatment center

Advanced water treatment(AO method)
Atsuta water treatment center

Shrinkage of Rainwater
screen slit
Takakura pumping station
Ushimaki pumping station
Tenmacho water treatment center(under installing)

The number ofGarbage Removal equipment

Total plan
45

Constructed Future Plan
41
420

■Advanced water treatment◆Atsuta Water Treatment Center（Anaerobic-aerobic method）
Sewage treatment capacity：about 38,000m3/day
OSP

Reactor tank

Organic substance

Final setting tank

Phosphourus
Anmonia

AnmoniaP

SewageAnmonia
AnmoniaP P PPOSPPPPPPPPAir

SludgeAnaerobictank

Aerobictank

Sludge treatment center

The process can remove nitrogen and phosphorus which causes
eutrophication more than normal conventional activated sludge
process.

21

■Advanced Facilities of simple treatment（Improvement of combined sewer system）
We changed the simple treatment of rain water from Settling treatment toFiltration treatment, remodeled the part of Existing First settling basin andinstalled Advanced Facilities of simple treatment in the water treatment
center.
Tenmacho water treatment center （treatment capacity：168,000m3/day）・Started operation in 2011
Horidome water treatment center （treatment capacity：277,200m3/day）・Started operation in 2018

Treatment flow

Special filteration materilal※Left figure is Tenma Water Treatment Center◆Removal Rate of BOD ： 20%-30%➡ 50%-60% Improvement!

22

■Rain-water Reservior for pollution controll（Improvement of combined sewer system）
We Construct rainwater storage facilities to reduce pollution loadfor Horikawa River in rainy weather by storing high polluted firstflush rainwater temporarily.
Takatuzhi
Rain-water Reservior

Fukue
Rain-water Reservior

Improving facilitys ofcombined sewer systemin Wakamiya avenue
Rain-water Reservior

Started operation in 1987

Started operation in 1999

Started operation in 2002

（30,000ｍ3）（26,000ｍ3）（19,000ｍ3）
23

■Removal and Reduction of inflow of pollutants
The number of installation ofGarbage Removal Device◆Improvement of combined sewer system(Installation of Garbage Removal Device)
BeforeTotal Plan

InstalledFuture plan toinstall

45414

Garbage RemovalDevice
Overflow

Wastewater
Treatment Plant

Garbage in sewerage
overflows together
with rainwater

After

Wastewater
Treatment Plant

Overflow•Rainwater treated by thegarbage removal devices
overflow into river•Removed garbage is treated atWastewater Treatment Plant
together with sewerage24

■Shrinkage of Rainwater screen slit
（ Improvement of combined sewer system ）Rainwater screens are the facilities to remove comparatively big garbage,and installed in water treatment centers and pumping stations.
Shrinkage of Rainwater screen slit remove more garbage.
•Takakura pumping station•Ushimaki pumping station•Tenmacho water treatment center(under installing)◆Rainwater screen slit
４０mm → ２５mm
◆Reduction of inflow of pollutants

25

Implementation byEnvironment Bureau26■Examination survey for river clarification(2019)
Survey Erea

Ozone
Layer

Shin-horikawa River

Ozone Layer（Groundwater）

Basic survey to effectively use ground water
as source of the river and water quality
improvement◆Application of ground water forclarification◆Survey about measure toincrease Spring water of Yamazaki
river27

■ Application of ground water for clarification
About Shin-Horikawa that has water quality problem,
We will conduct a basic survey to effectively use groundwater as source of water quality improvement.

In order to securewater source
In order toimprovewater quality□ Information gathering
・Boring data
・Water leaketc.

□Consideration of model case2020～Survey will be concrete28