PUBLIC WORKS BUREAU > Introducing our Projects > Sewerage system improvement
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Introducing our Projects
Burying electrical cables Developing multipurpose underground conduits Water-retentive pavement Development projects along the edge of the Dotonbori River
Hirano River Flood Control Reservoir JR Hanwa Line grade separation project Sewerage system improvement    

Sewerage system improvement


To build a community that is not susceptible to impact of rain
The Osaka Plain is an alluvial plain created by accumulation of earth and sand, etc. from the Yodogawa and other rivers. For this reason, approx. 90% of Osaka City area (with the exception of Uemachi-daichi Plateau, etc.) is susceptible to the impact of rain, necessitating water displacement by pumps.
Although the sewerage of Osaka City covers almost 100% of the area, flooding occurs even today in times of localized torrential rain.
For this reason, Osaka City is committed to building sewerage trunk lines as well as expanding new and existing pumping facilities in an effort to create a flood-free community where safety and amenity are ensured. Other fine-tuned measures include installation of manhole pump systems for local discharge.
To create an urban environment with enhanced amenity
To protect the global environment and build a community with enhanced amenity and attractiveness, Osaka City promotes recycling of sewerage resources and energy (including treated water, sludge and heat) as well as aboveground space of sewerage facilities, etc.
Tree diagram of sewerage system resources
Tree diagram of sewerage system resources
To put in place a better sewerage system for the next generation
Sewerage improvement projects undertaken by Osaka City were launched in the Meiji period (1868-1912). Due to their long operation, the condition of a growing number of sewerage facilities has deteriorated.
If these deteriorated facilities were left unattended, it would lead to problems including: collapse of roads due to damaged sewer pipes; decline in operating capacity of equipment at pump stations and sewage treatment plants; increase in maintenance costs.
To maintain sewerage facilities properly and efficiently, these deteriorated facilities will be rebuilt and renovated systematically to meet social needs.
Inventory of deteriorated facilities (as of the end of FY 2004)
Inventory of deteriorated facilities (as of the end of FY 2003)
Deteriorated sewer pipe / drain
Deteriorated sewer pipe / drain
Renovated sewer pipe / drain
Renovated sewer pipe / drain
To create a clean water environment
Wastewater from households, etc. is cleaned at sewage treatment plants before released into the rivers and the sea. Thus sewerage is designed to safeguard the quality of natural waters as well as the environment.
In Osaka City, complete treatment is performed at all the sewage treatment plants. Water quality of rivers in the city has improved significantly since around 1970 when the sewerage system was extensively developed. However, some of the rivers have not met environmental standards on water pollution. In addition, Osaka Bay suffers red tide every year.
Most areas of Osaka City are serviced by combined sewerage systems where rainwater and wastewater (from households and corporate entities) are collected in the same sewer pipes. Combined sewerage systems have one drawback, however. When intensity of rain exceeds a certain limit, some pollutants and waste, etc. flow directly into rivers together with the rainwater, which results in water pollution.
To meet environmental standards on water pollution and create a cleaner water environment, Osaka City is working on construction of remedial facilities for combined sewerage and advanced treatment facilities as well. These efforts are intended to improve water quality of the Dotonbori-gawa and Higashi-Yokobori-gawa Canals.
In addition, all the sewage treatment plants will be connected by piping to transport and treat sludge efficiently. With completion of the phase I construction project, "Maishima Sludge Center" (an intensive sludge treatment facility) will also undergo further development.
Improvement in combined sewerage system and advanced treatment
Water purification measures at the Dotonbori-gawa and Higashi-Yokobori-gawa Canals
Top view
Cross section
Sludge pipe transportation map
Sludge pipe transportation map
Maishima Sludge Center
Maishima Sludge Center
Building an earthquake-resistant sewerage system
Wastewater receiving facilities for temporary restrooms

Wastewater receiving facilities for
temporary restrooms

Like water, electricity and gas, the sewerage system is one of the lifelines that support citizens' life.
For this reason, arrangements must be made so that sewerage facilities sustain their operations and serve as disaster prevention facilities when disasters such as an earthquake occur.
To this end, sewage treatment plants and other buildings are reinforced based on earthquake resistance investigations. Efforts are also made to fully equip facilities with private power generation units. In addition, Osaka City will improve wastewater receiving facilities for temporary restrooms at area-wide shelters, etc. as well as fire prevention and daily life water supply equipment that makes use of advanced treatment water recycled from sewage.
  Fire prevention and daily life water supply equipment
    Fire prevention and daily life water supply equipment
To improve efficiency of administration
Remote supervision and control
Efforts are made to improve efficiency of administration. For example, a remote supervision and control system will be established to enhance efficiency in maintenance of sewerage facilities, and integrate and centralize the monitor room. When deteriorated facilities are rebuilt and renovated, they will be consolidated based on a scrap-and-build scheme.
To ensure safety of the sewerage system
To expect the sewerage system to work properly, it is necessary to maintain the facilities (including sewer pipes, pump stations and sewage treatment plants) correctly at all times.
Sewer pipes have to be cleaned, repaired or replaced to ensure smooth flow of sewage. Day-to-day inspections are also indispensable.
Sewage continues to flow into the facilities day and night. Furthermore, localized torrential rainfall is not predictable. Under these circumstances, the staff must control operation around the clock at pump stations and sewage treatment plants. It is also imperative to inspect and repair facilities. Efforts are also made to maximize efficiency of operation to meet ever changing water volume.
Checking sewer pipes with a mobile camera-equipped probe
Checking sewer pipes with a mobile camera-equipped probe
The sewerage system is our valuable asset.
The sewerage system is our valuable asset.Your small-scale care saves the sewerage system.
Please refrain from discharging cooking oil and disposer-crushed garbage from the sink, or flushing hard paper, etc. in the toilet.
Please remove waste, etc. that may clog gutters and catchment pits.
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