334
water source
activity
0 = sludge
storage
in tank
septic tank
domestic
neighborhood
plant
sewerage
system
---------sewerage
offieeand
system
commercial
septic tank
sewerage
system
industry
direct
discharge
K. Takao . B.T. Bower
munidpal
sewage
treatment
plant
water
environment
Fig. 18.3. Schematic of water intake and wastewater discharges for domestic, office, commercial, and
industrial activities, Tokyo Bay region
Installation of, and connection to, a sewerage system have occurred only recently,
except for the central areas of Tokyo and Yokohama. In 1980 about 42% of the population in the Tokyo Bay watershed was estimated to be connected to a municipal sewerage system. There were 60 municipal sewage treatment plants in the Tokyo Bay watershed; 25 of them discharged directly to the bay and the reminder discharged upstream
into rivers tributary to the bay. Storage of nightwaste for subsequent collection is seen
only in rural areas, as this method is associated with traditional non-water toilets.
The Water Pollution Control Law of 1970 established a set of the world's toughest
emission standards applicable to wastewaters from manufacturing industries; the standards have been further strengthened since then. Factories equipped with certain water-related facilitie's are required to register them with the prefectural governments and
to monitor the quantity and quality of their effluents periodically. Wastewater discharges from industrial activities in 1980 were estimated, based on their industrial water
intakes, to be about 2.6 million m 3 d-t, down from 4.2 million m 3 d- 1 in 1970. This decline in industrial water intake was maiply associated with increased water reuse, which
comprised approximately 85% of total industrial water use in 1980.
Estimated COD and DIN loads to Tokyo Bay are shown in Table 18.4. The table shows
the loads in terms of the four categories of sources identified, i.e.:
• River inputs: loads carried via 20 major rivers tributary to Tokyo Bay;
• Industrial activities: loads from coastal indp.strial factories and plants;
water source
activity
0 = sludge
storage
in tank
septic tank
domestic
neighborhood
plant
sewerage
system
---------sewerage
offieeand
system
commercial
septic tank
sewerage
system
industry
direct
discharge
K. Takao . B.T. Bower
munidpal
sewage
treatment
plant
water
environment
Fig. 18.3. Schematic of water intake and wastewater discharges for domestic, office, commercial, and
industrial activities, Tokyo Bay region
Installation of, and connection to, a sewerage system have occurred only recently,
except for the central areas of Tokyo and Yokohama. In 1980 about 42% of the population in the Tokyo Bay watershed was estimated to be connected to a municipal sewerage system. There were 60 municipal sewage treatment plants in the Tokyo Bay watershed; 25 of them discharged directly to the bay and the reminder discharged upstream
into rivers tributary to the bay. Storage of nightwaste for subsequent collection is seen
only in rural areas, as this method is associated with traditional non-water toilets.
The Water Pollution Control Law of 1970 established a set of the world's toughest
emission standards applicable to wastewaters from manufacturing industries; the standards have been further strengthened since then. Factories equipped with certain water-related facilitie's are required to register them with the prefectural governments and
to monitor the quantity and quality of their effluents periodically. Wastewater discharges from industrial activities in 1980 were estimated, based on their industrial water
intakes, to be about 2.6 million m 3 d-t, down from 4.2 million m 3 d- 1 in 1970. This decline in industrial water intake was maiply associated with increased water reuse, which
comprised approximately 85% of total industrial water use in 1980.
Estimated COD and DIN loads to Tokyo Bay are shown in Table 18.4. The table shows
the loads in terms of the four categories of sources identified, i.e.:
• River inputs: loads carried via 20 major rivers tributary to Tokyo Bay;
• Industrial activities: loads from coastal indp.strial factories and plants;