(Units: mg /L )
Item
Intake Discharge Water qualityBiblioteka waterwater
standard
BOD
156
3
25
COD
79
11
35(15)
Total nitrogen
31.9
15.0
30(20)
Total phosphorus
3.5
1.2
3( 1)
Averages of all 13 water reclamation centers. Figures in parentheses are water quality levels from water reclamation centers using advance treatment techniques.
Pumping stations Water collected in sewers passes through pumping stations,
where it is sent on to water reclamation centers. Sewers are set at an angle to allow wastewater to naturally flow downwards, so the sewers can end up rather deep underground.
Annually:
1,778,566,200 m3
Daily average: 4,872,780 m3
Tsinghua University, Apirl 1, 2010
23
Total population and sewer penetration rates in 23 ward area
Population 8.49 million
Tsinghua University, Apirl 1, 2010
2
History of sewerage system in Japan
The first sewerage system in Japan can be seen in the large communities in the Yayoi Period (approximately 2,200 years ago). In the Nara Period (about 1,300 years ago), a drainage system network ran throughout the city in the Heijo-kyo capital area. In the Azuchi-momoyama Period (approximately 430 years ago), a stone culvert called the Taiko Sewerage was built around Osaka Castle. It is still in use today.
Industrial complex in Kitakyushu City
Improvement of water quality and conservation of water environment
11
Tsinghua University, Apirl 1, 2010
12
2
Three components of Sewerage systems
16
Separate and Combined drainage systems
Separate and Combined drainage systems
Stormwater pipe and sewer pipe
Tsinghua University, Apirl 1, 2010
17
Combined sewer pipe
Tsinghua University, Apirl 1, 2010
3
Tsinghua University, Apirl 1, 2010
4
Tsinghua University, Apirl 1, 2010
5
Tsinghua University, Apirl 1, 2010
6
1
Oxidation Ditch System SBR System
Tsinghua University, Apirl 1, 2010
21
Tsinghua University, Apirl 1, 2010
22
Sewerage in the 23 ward area
Total length of sewer
15,576,259 m
Manholes
476,117
Another important function of pumping stations is to guard against flooding. Pumping stations act to quickly discharge water left by heavy rains into the ocean or rivers.
Primary settling
Advanced treatment Disinfection
Tsinghua University, Apirl 1, 2010
15
Activated sludge process
(Bioreactor and secondary settling)
Tsinghua University, Apirl 1, 2010
Water reclamation centers Water reclamation centers treat wastewater and sludge.
Wastewater treatment involves passing the wastewater through a system of tanks. Tokyo Metropolitan Government Sewerage Bureau manages 20 centers that treat around 5.8 million cubic meters of wastewater each day.
http://www.gesui.metro.tokyo.jp/english/no02.htm
Tsinghua University, Apirl 1, 2010
13
Tsinghua University, Apirl 1, 2010
14
Pumping station
Pretreatment
Sewer system
New Roles and Missions of Sewage Works in Japan
Hiroaki FURUMAI,
Professor, Research Center for Water Environment Technology University of Tokyo
Tsinghua University, Apirl 1, 2010 1
bodies. They have greatly contributed to improvement in living environment. In other words, sewerage system has a important role as essential element of the urban infrastructure in supporting wholesome and cultural life and urban activities
Tsinghua University, Apirl 1, 2010
25
Water quality and sewer operations on the Sumida River
mg/l
Penetration rate (%) Water Quality (BOD)
*Penetration rate exceeds 99.5% and considered equal to 100%.
Tsinghua University, Apirl 1, 2010
24
4
Average water quality of water reclamation centers in 2004 Total water discharged is 4.36 million m3 per day.
Pumping station
78
Volume of water pumped in 2004 Annually: 852,449,750 m3
Daily average: 2,335,480 m3
Water reclamation centers
13
Volume of water treated in 2004
Sewage works have played a major part in Wastewater collection and treatment, Flood and inundation control Conservation of water quality in public water
Tsinghua University, Apirl 1, 2010
18
3
Tsinghua University, Apirl 1, 2010
19
Tsinghua University, Apirl 1, 2010
20
Sewerage Systems in the Ward area
Regional Sewerage Systems in Tama Area