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Effective Japanese Domestic Wastewater Treatment Technology
Dr Yoshitaka EBIE
National Institute for Environmental Studies, JAPAN(E-mail:
[email protected])
Parallel Session II
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Characteristics of domestic wastewater in Japan
Water consumption BOD loads per capita per day
200 L/person/day 40 gBOD/person/day10 gN/person/day1
gP/person/day
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Domestic wastewater treatment
WWTP
87,800 thousand people
(68.9%)
Johkasou
14,100 thousand people(11.1%)
Centralized system
Decentralized system
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Deemed Johkasou treating night soil only
14,700 thousand people(11.5%)
Vault toilet+ night soil
treatment plant
10,800 thousand people(8.5%)
Domestic wastewater treatment
Decentralized system
Decentralized system
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Johkasou
Johkasou has been developed in Japan as a decentralized
wastewater treatment facility.
Johkasou
Sewage treatment
plant
Johkasou
Sewer pipe
Night Soil Treatment Plant
Night Soil Treatment Plant
Vault toilet
Low-population density area or valley
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National structure standards-compatible Johkasou
5 - 50 PE
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Model of Johkasou for 5 PE
1st anaerobic tank
Influent Effluent
2nd anaerobic
tank
Aerobic tank
Sedimentation tank
Influent: 1 m3/dayBOD: 20 mg/LSize: around 3 m3
-
Johkasou for 5 persons which has been operated for 15 years
-
Effluent Effluent
Anaerobic tank 1 Anaerobic tank 2 Aerobic tank and disinfection
tank
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National structure standard-compatible
Performance certificatedAuthorized by Minister of land,
infrastructure and
transport of Japan
New technology
Compactness, Hybrid
Advanced treatment
Development of advanced Johkasou
Japan's Building Standards Act
Johkasou
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Performance certified Johkasou
1. Short-term test with temperature control 16 weeks (or 8 weeks
in parallel) 13 and 20C with influent control
2. Outside long-term test 48 weeks with influent control
3. On-site household test 48 weeks without influent control at
least 3 sites
Temperature controlled test room
The performance test is done by the third party
Based on 2000 amending act, makers became able to develop
original Johkasou and sell it based on performance
certification.
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Influent pattern for 5 PE
Washing machine
Bath KitchenToilet
JohkasouWhen you use water, influent
comes to Johkasou.
0
50
100
150
200
250
300
3 5 7 9 11 1 3 5 7 9 11 1
Influ
ent
volu
me
(L)
Timeam pm
Total 200 L/PE/day
Daily influent pattern of domestic wastewater for 5 PE.
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Performance certified Johkasou
1. Compact type
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Operation and maintenance
Initial inspection Operation Desludging Annual inspection
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Annual inspectionBasic information
(Date of installation, list of related vendors, use of building,
number of users number of users for designing, treatment process,
designed effluent quality)
Visual inspection Water quality inspection Document
inspection
Observe the installation condition and examine the inside of
johkasous by eye, items for both inspection after construction and
annual inspection are:
installation conditionoperational condition of devicescondition
of water flowingcondition of useodor problemcondition of
disinfection
Items for inspection after construction include:
Items for annual inspection are usually a), c), d), f) and g).
BOD measurement can be introduced according to the district
situation.
In inspection after construction, whether a johkasou was
installed appropriately or not is examined based on the maintenance
record.
In annual inspection,whether a johkasou was maintained and
cleansed appropriately or not are examined based on the
mainte-nance record, cleansing record and the last inspection
record.
Evaluate the individual inspection item in three classes "Good",
"Pass", "Bad"
Arrange the inspection results
Synthetically evaluate the importance of individual item
considering effect on discharge site and public health
Final judgment: "Good", "Basically good", "Bad"
Figure 2 Inspection content and procedure of legal
inspection
a) pHb) Sludge volumec) Dod) Transparencye) Cl -f) residual
chlorineg) BOD
******
Basic information(Date of installation, list of related vendors,
use of building, number of users number of users for designing,
treatment process, designed effluent quality)
Visual inspection Water quality inspection Document
inspection
Observe the installation condition and examine the inside of
johkasous by eye, items for both inspection after construction and
annual inspection are:
installation conditionoperational condition of devicescondition
of water flowingcondition of useodor problemcondition of
disinfection
Items for inspection after construction include:
Items for annual inspection are usually a), c), d), f) and g).
BOD measurement can be introduced according to the district
situation.
In inspection after construction, whether a johkasou was
installed appropriately or not is examined based on the maintenance
record.
In annual inspection,whether a johkasou was maintained and
cleansed appropriately or not are examined based on the
mainte-nance record, cleansing record and the last inspection
record.
Evaluate the individual inspection item in three classes "Good",
"Pass", "Bad"
Arrange the inspection results
Synthetically evaluate the importance of individual item
considering effect on discharge site and public health
Final judgment: "Good", "Basically good", "Bad"
Figure 2 Inspection content and procedure of legal
inspection
a) pHb) Sludge volumec) Dod) Transparencye) Cl -f) residual
chlorineg) BOD
******
Visual Water quality Documents
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Johkasou technician
Qualifications Registrant Business contentOperator 68,668
O&MInstallation worker 81,464
Installation/constructionTechnical supervisor
25,105 501 PE or more
Desludgingtechnician
14,782 Desludging
Inspector 1,119 Inspection
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Japanese decentralized wastewater treatment system, Johkasou is
effective in low population density area.
Key points to keep Johkasou in good condition are Periodical
O&M Appropriate desludging Inspection and improvement
Asian standard for performance test and related legislation
Short summary
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Greenhouse effect gas emission
Emissions of greenhouse gases such as CH4 and N2O from
wastewater facilities must be accounted certainly to report
UNFCCC.
Washing machine
Bath KitchenToiletCH4, N2O
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Model of Johkasou
1st anaerobic tank
Influent Effluent
2nd anaerobic
tank
Aerobic tank
Sedimentation tank
Anaerobic-aerobic
Circulation
Effect of anaerobic-aerobic circulation on GHGs emission
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Comparison of CH4 emission
0 200 400 600 800
1,000 1,200 1,400 1,600 1,800 2,000
10:00 14:00 18:00 22:00 2:00 6:00 10:00
CH4
(ppm
)
Time
Run 1Run 2
Run1no circulationRun2circulation ratio 4
72% reduction
613
174
0
100
200
300
400
500
600
700
Run1 Run2
CH4
ppm
Average CH4 conc
1. At the time of inflow peak, highest CH4concentration was
observed in both runs.
2. The peaks of both run were very sharp.
Fluctuation caused by inflow of domestic
wastewater
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Comparison of N2O emission
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
16.0
18.0
10:00 14:00 18:00 22:00 2:00 6:00 10:00
N2O
(ppm
)
Time
Run 1
Run 24.2
1.9
0.0
1.0
2.0
3.0
4.0
5.0
Run1 Run2
N2O
pp
m
Average N2O conc
55% reduction
Run1no circulationRun2circulation ratio 4
1. At the time of inflow peak, highest N2O concentration was
observed in both runs.
2. The peaks of both run were broad and the influence of inflow
was kept in a few hours.
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Anaerobic-aerobic circulation operation led 72% and 54% of CH4
and N2O reduction in Johkasou.
This result means 68% reduction of CO2eq.
Therefore, anaerobic-aerobic circulation operation for nitrogen
removal contributes significantly to greenhouse gases reduction in
Johkasou.
Summary
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Major standards in the world
European Standard (EN)EN12566-3: Small wastewater treatment
systems for up to 50 PE
The United StatesNSF/ANSI Standard 40: Residential Wastewater
Treatment Systems
AustraliaAS/NZS 1546 Part 3: Aerated wastewater treatment
systems
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Standard for Asia?
Characteristics of Asia-Pacific region Climate
Monsoon, heavy rain, dry season, etc Water environment
Characteristics of wastewater (volume and conc.) Food culture
Economic area Way of thinking etc
Asian Standardor mutual recognition in Asia
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