Japan's Experience in Decentralized Sanitation - Japan Sanitation ...

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28 Feb 2012 ... Japan Education Center of Environmental Sanitation. Aizawl, INDIA ... Night Soil and Domestic Wastewater Treatment Systems in Japan. 2 ...
Japan’s Experience  in  Decentralized Sanitation (Johkasou) Decentralized Sanitation (Johkasou) Xinbi Yang Japan Education Center of Environmental Sanitation

Aizawl, INDIA 28 Feb. 2012 1

Night Soil and Domestic Wastewater Treatment Systems  in Japan

2

Population Served by Different Systems Population Served by Different Systems

14%

Sewerage system Rural sewerage system Johkasou system Night soil treatment

9% 74%

3%

(as of the end of FY 2009)

100 90

(as of the end of FY 2009)

99.4

90.3

88.9

84.5

80

Perrcentage, %

70

78.0 71 0 71.0

S off major Sum j domestic d ti wastewater t t ttreatment t t systems t

60 50 40 30 20 10

0.5

5.9

7.5

9.6

300-500

100-300

16.9

13.9

Johkasou system

0 More than 1,000

500-1,000

50-100

Less than 50

Size of municipalities, thousand people 3

Number of Installed Johkasou Johkasou:2.9 million units Tandoku-shori johkasou:5.45 million units (as of the end of FY 2009)

65.3% 34.7%

A small-scale johkasou 4

Advantages Ad t off JJohkasou hk System S t for f Decentralized Treatment  Low initial investment cost  Little topographic limitation, short installation time and early realization of the effects  Invaluable contribution to maintaining sufficient water in small rivers and aquatic environments near inhabited areas  Johkasou-treated water and sludge are easy to reuse  Less vulnerable to earthquakes and other disasters

5

Pollutant Loads for Johkasou Design

Determination of Johkasou Size in Buildings Classified by Purpose of Use (Examples) JIS A 3302 2000

Structure and Treatment Performance of Johkasou

Treatment Principles of Johkasou

9

A small small-scale scale Johkasou (FRP)

Diffusion pipe

Effluent water quality BOD