Advantages of Japanese on-site treatment system
- The history of night soil treatment in Japan -
Akira Morita
Japan Sanitation consortium/
Japan Environmental Sanitation Center
■~1950s : Agricultural use ✓Human waste was collected and recycled as a fertilizer for rice farming before the diffusion of chemical fertilizer in 1940s.
■1950s ~ : From Valuable Material to Waste ✓Worsening of Environmental Pollution ✓Spread of Hygienic Disposal ✓Establishment of Institutions for Environmental Sanitation.
■1980s~ : Sustainable Development ✓Recycling (Energy&Biomass) ✓Global Warming (Energy saving)
History of Sanitation in Japan
2
Major systems for night soil and grey water treatment
(Vault and vacuum toilet)
Night soil+grey water
Night soil
3
Wastewater treatment facility
Population trends for on-site & off-site sanitation systems in Japan
4
0
20
40
60
80
100
120
140
Po
pu
lati
on
, mill
ion
Dumping into the sea
Disposal to the nature without treatment
1955 1965 1975 1985 1995 Year
Development of human waste management in Japan (1955 - 2010)
2005
Vault toilet + Night soil treatment plant
Public sewerage system
1960 ’70s ’80s ’90s After 2000
Prevention from diseases
Pollution Control
Environmental Protection
High efficiency & Compactification
Resources Reclamation
Inn
ovative level o
f techn
olo
gy
Energy & Biomass recycling
Removal of N・P
Elimination of Foul air, COD & Color
Hygienic Sanitation and Removal of SS ・BOD
Anaerobic Digestion
Aerobic Digestion
Denitrification Process
High-rate membrane
Process
Sludge Treatment
system with recycling
5
History of Technology Innovation for Night soil Treatment In Japan
1900 1920 1940 1960
Inn
ovative level o
f techn
olo
gy
History of Technology Innovation for On-site Treatment in Japan
1980 2000 2010
PAWTP
(Black water only type)
Eff.<BOD 90mg/L
1950
PAWTP
(Both black + grey water type)
Eff.<BOD 20mg/L
(<T-N 20mg/L)
1970
Packaged Aerated Wastewater Treatment Plant (PAWTP – Johkasou)
Low Technology (Anaerobic treatment)
Oxidation Bed Process
(Black)
Eff. <BOD 130mg/L
Soil trench process
(Black)
Eff. <BOD 20mg/L
Unit-type Plant-type
Small-scale Medium-scale Medium/Large-scale
(5~50人程度) (50~500人程度) (500人程度以上)
Fig. 1 Fig. 2
Fig. 4 Fig. 3
6
Flush toilet water Flush toilet water & Grey water
Flush toilet water
Flush toilet water
Classification of on-site treatment technology system in Japan
Floating organism method ・ Activated sludge process ・ Contact aeration process ・ Rotating biological contactor process Natural method ・ Soil trench, (Wetland) Vault toilet method ・ Vault and vacuum toilet ・ Urine/Feces separating compost toilet
PAWTP (Johkasou)
Mountain/Park toilet
Mountain toilet
PAWTP (Johkasou) system in Japan
Night soil/Sludge Treatment Facility
(Desludging)
Effluent: <BOD20mg/L
(Transport)
Unit-type Plant-type
Small-scale Medium-scale Medium/Large-scale
(5~50人程度) (50~500人程度) (500人程度以上)
Unit-type Plant-type
Small-scale Medium-scale Medium/Large-scale
(5~50人程度) (50~500人程度) (500人程度以上)
Unit-type Plant-type
Small-scale Medium-scale Medium/Large-scale
(5~50人程度) (50~500人程度) (500人程度以上)
Unit type: 5-50PE Unit type: 50-500PE Plant type: >500PE
Night soil
(O&M)
8
What is PAWTP (Johkasou)?
• Advanced domestic waste
water treatment system (tank)
developed in Japan
• Treats wastewater as clean as
BOD 20mg/L
• Treats not only black water but
also grey water
• Operated for 11 million Japanese people in less populated
areas around Japan, as a technique which is cost‐effective and
able to be installed in a short time.
9
Revision of Johkasou Act
Revision of Johkasou Act
National subsidy program (Municipal Johkasou installation)
0
500,000
1,000,000
1,500,000
2,000,000
2,500,000
3,000,000
3,500,000
4,000,000
1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013
Johkasou Act (effective in 1985)
National subsidy program (Johkasou
installation promotion)
■PAWTP (Johkasou – Both black and grey water type)
Number of PAWTP 3,333,623
Num
ber
of
PA
WT
P (
Johkasou
) Number and Trends of installed PAWTP (Johkasou – Both
black and grey water type)
Year
10
Outline of On-site Technologies
On-site technology Advantages Disadvantages
Pit latrine -Water and electricity are not required.
-The installation cost is inexpensive.
-Unsanitary -Groundwater contamination
Composting toilet -Water and electricity are not
required. -Turn to soil of farmland
-Difficult without agricultural demand
Septic tank -Flush toilet is possible. -Electricity is not required. -Less sludge production
-Secondary treatment is required. -Limitation in treatment performance
-Source of colon bacillus
contamination
Johkasou -Environment-friendly -High treatment performance -Measures against colon bacillus contamination is possible.
-Electricity is required. -More sludge production
Performance of septic tank system
• Effluent water quality
• Sludge generation
0.17L/PE/day • Properties of Septage
(Source: Hidenori Harada)
(Source: JICA)
COD Cr BOD SS T-N T-P
Average 31900 6480 12900 590 210
Range 1500-703000 440-78600 310-93400 66-1060 20-760
(mg/L)
Source: USEPA(Black+Grey)
12
Variety of sludge treatment method (1/3) - Integrated Processing in Sewage Treatment Plant -
Sewage Treatment Plant
Homogenised
Dehydrated sludge
Vacuumtruck
Rece ivingtank
ⓟ(Expansion)
Bar screanuni t
Aerationstrage
tank
Pumppi t
ⓟⓟ
Dehydrator
Disposal
Sewage Treatment Process
Super natant
Excess Sludge
sludgeSludgestrage
tank
13
Receiving facility for sludge from on-site treatment facility 【Method-1 Flow Sheet】
Variety of sludge treatment method (2/3) - Integrated Processing in Sewage Treatment Plant -
Sewer treatment plant
Receiving facility for sludge from on-site treatment facility 【Method-2 Flow Sheet】
Receiving facility for sludge from on-site treatment facility 【Method-2 Flow Sheet】
Variety of sludge treatment method (3/3) - Independent Sludge Treatment Plant -
15