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Kasai Water Reclamation Center

photo:kasai water reclamation center

Kasai Water Reclamation Center, which is located at the mouth of Arakawa River,consists of facilities in the southern and northern areas that sandwich the Metropolitan Expressway Bayshore Route. Its treatment area is 4,893 ha, including most of Edogawa Ward surrounded by Arakawa River and Edogawa River and a part of Katsushika Ward.
Treated wastewater is discharged into Tokyo Bay (Arakawa River), while some of it is sand-filtered and used for washing/cooling machines and flushing toilets in the Center.
Generated sludge incinerated within the Center together with sludge pumped from Nakagawa Water Reclamaiton Center and Kosuge Water Reclamation Center.
The treatment area has 8 pumping stations, 4 of which are operated remotely from Kasai Water Reclamation Center.



Operation started September 1981
Site area


Treatment capacity 400,000m3/day
Wet weather Storage tank 87,300m3
Stormwater storage tank 69,000m3
Wastewater treatment facilitiesGrit chamber 18
Primary sedimentation tank 10
Reaction tank 10
Secondary sedimentation tank 10
Slude treatment facilitiesThickener 4
Concentrator 7
Dewatering machine 18
Incinerator 3

Average quality of influent and final effluent

The final effluent from the water reclamation center complies completely with the water quality standards of the Tokyo Metropolitan Environmental Security Ordinance and is sufficiently clean for fishes to live in.


ItemInfluentFinal effluentRegional water quality standards
BOD 160 5 -
COD(Mn) 76 10 35 or bellow
Total nitrogen 27.1 10.6 30 or bellow
Total phosphorus 3.1 0.9 3 or bellow

Average values of 24-hour test conducted in FY2018

※ The higher values of BOD and COD indicate the higher levels of water contamination. BOD describes the amount of oxygen required by microorganisms to eat organic material in water, and COD describes the amount of oxygen required by oxidizer to decompose organic material in water. The quality levels of discharged water are specified in terms of BOD for rivers and COD for seas. Total nitrogen and total phosphorus are closely related to the generation of red tides.

Sewerage Components

The sewerage system is principally made up of 3 facilities.
Sewers, which collect and carry sewage.
Pumping stations, where sewage is pumped up so that the sewers do not get too deep.
Water reclamation centers, where sewage is treated to be clean water.
Inspections, cleaning, and repairs are done daily in order to make sure each of these facilities works properly.

Illustration:Sewerage System Components

The Role of Tokyo Sewerage

Improvement of Living Environment through Wastewater Treatment

Wastewater discharged from homes and factories is treated to ensure a comfortable living environment.

Illustration:Improvement of Living Environment through Wastewater Treatment

Preventing Flooding through the Removal of Stormwater

The city is protected from flooding through the speedy drainage of stormwater which falls on land surface.

Illustration:Preventing Flooding through the Removal of Rainwater

Protecting the Global Environment

We treat sewage and release cleaned water, to carefully protect the water quality of rivers and the sea. We also recycle treated water and sludge, and utilize unused energy, as we work to build a recycling city.

Illustration:Protecting the Global Environment

Ground plan

Illustration:kasai graoud plan

Features of Kasai Water Reclamation Center

Photovoltaic (Solar) Power Generation

To help prevent global warming, a photovoltaic power generation system, which does not emit CO2 at the time of power generation, was installed and the generated power is consumed by the Center as part of its total power consumption.
The total power generation capacity is 490kW, 290kW of which is generated by single-axis tracking type generators.The annual power production is equivalent to the power consumed by 160 ordinary households.

photo:single-axis tracking type photovoltaic cell

Single-axis tracking type photovoltaic cell

Nas (sodium-sulfur) Battery

We reduce the electricity bill by using power in the daytime that was saved in the sodium-sulffur battery in the nighttime with low power rate.
Also we trckle with the power shortage caused by power demand control.

photo:NaS battely

Nas Buttery

Small-scale Hydroelectric Power Generator

The outfall for the treated water is installed several meters higher than the sea level to protect it against high tides. Hydraulic power is generated by utilizing this effluent drop.
The output of the generator is 27kW, and the annual power generation is equivalent to the power consumed by over 20 ordinary households. As power is generated without emitting CO2, hydroelectric power genration mitigates global warming.

photo:hydroelectric power generator

Schematic diagram of small-scale Hydroelectric Power Generation

Seafront Ballpark on top of the Treatment Facilities

The Edogawa Ward seafront ballpark, which has been built on the space above the treatment facilities, is used by many people to play soccer, baseball, etc. The ballpark can be turned into an evacuation area in case of an earthquake disaster.
Application for use: Edogawa Ward Seafront Ballpark


Treatment facilities are underneath the ballpark

Kis's square

We are promoting multi-purpose use of sewerage facilities: the square is used as a square for events and visiting kids.

photo:kid's square.jpg

kid's square

Turbocharged Fluidized Bed Incinerator

We introduce efficient incinerator such as high-temperature energy-saving type incinerator and reduce energy consumption and N₂O gas emission.


Sawayaka(fresh)Smoke Stack

To commemorate the 20th anniversary of the Center, local elementary school students were asked to create designs for the smoke stack. The old smoke stack, which was painted red and white, was reborn in 2001 with a fresh blue gradation.

photo:smoke stack

Smoke stack rising into the blue sky

Guide map


 1-1-1, Rinkai-cho, Edogawa Ward, Tokyo 134-0086 MAP

Access Get off Nishi Kasai Station on the Tokyo Metro subway, take a metropolitan bus bound for "Rinkai-cho 2-chome Housing Complex," get off at "Tokyo Rinkai-Hospit" or "Rinkai-cho-1-chome," and walk for 10 minutes to the Reclamation Center.
Get off at Kasai Rinkai Park Station on the JR keiyo Line and walk for 20 minutes to the Reclamation Center.

Illustration:kasai gaide map

Tokyo Sewerage Museum "Rainbow"

Tokyo Sewerage Museum Rainbow logo
There is a facility to enjoy the experience of learning about the sewerage system, its roles, and the importance of water environment.

  • Hours nine half o'clock to sixteen half
  • Entry Fee Free
  • Closed Mondays(open on holiday Mondays, closed the next day)and the New Year's season
    Open daily throughout the summer(July 16 - August 31)
    Open on Sewerage Day(September 10)and Tokyo Citizens Day(October 1)
  • Address 2-3-5 Ariake, Koto-ku Ariake Water Reclamation Center Management office(A-tower)5th floor
  • Telephone 03-5564-2458
  • Website Tokyo Sewerage Museum "Rainbow"

Bureau of Sewerage in Tokyo website

Tokyo Amesh

Tokyo Amesh is the system that shows rainfall in and around Tokyo in real time. The rainfall is measured by radars and ground rain gauges.

※ Tokyo Amesh is the registered trademark of the Tokyo Metropolitan Government.

Tokyo Amesh screen image

Virtual Sewerage

Animation and video are used to allow people to experience the sewerage system in a fun way that would not be normally possible.

click Virtual Sewer

Beware of croocked dealer who pretend to be related to the Bureau of Sewerage!

The Bureau of Sewerage does not rely on businesses to repair or clean drainage facilities in housing.

Facility tours of Water Reclamation Centers

Facility tours of water reclamation centers are available except weekends, holidays, and the New Year's season.
Please contact us about reservations and details.

Phone 03-3241-0944
Hours 9AM~5PM(weekdays only)

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