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