On--site Domestic Wastewater
OnTreatment in JapanDr Kiyoshi Kawamura
Dr.
Previous occupation: Professor, School of Science & Engineering,
Graduate School of Saitama Universityy1

Wastewater treatment facilityof a sewerage system
Treatment plant of a ruralsewerage system (installedinside of the building)Current systems for sanitation
SSeweragesystemt(Ministry of land, infrastructure, transport and tourism)

Rural sewerageg systemy(Ministry of agriculture, forestry and fisheries)

Johkasou, tandoku-shori johkasou, night soil storage tank((vaultlt andd vacuum toilet)
t il t) andd community
it plantl t(Ministry of the environment)
NightNi
ht ttreatment
tt plant
l t forf collected
ll t dnight soil and johkasou sludge(installed inside of the building)Household type johkasou(gappei-shori johkasou)2

Major systems for night soil and grey water treatment
Night soil＋grey water (Domestic wastewater) Community
Ci plant:l
Si il toSimilar
Rural sewerage system in technology, but different in administrative management.
Wastewater treatment facility

Johkasou: Formerly, johkasou
was called as gappei-shori johkasou.
Domestic
wastewater
treatment plantHousehold type johkasou(gappei-shori johkasou)(Formally Gappei(Formally,Gappei-shori
shori johkasou)Night soil

New installation wasbanned from 2001
(Vault and vacuum toilet)

Actually, no new
installation3

johka = purificationsou = tankjohkasou = purification tanktandoku = sole (only flush toilet wastewater)
gappei = combined (both flush toilet wastewater & grey water = domestic
wastewater)
shori = treatment
tandoku-shori johkasou = purification tank for treatment of only
flush toilet wastewatergappei-shori johkasou = purification tank for treatment ofdomestic wastewater
Tandoku-shori johkasous have been banned to install from 2001, andjohkasou means gappei-shori johkasou.
4Application of major domestic wastewater treatment systems

Johkasou(Gappei-shori johkasou)

Rural sewerage system

Sewerage system
Community plant: It isapplied in sub-urban
sub urban areas
without sewerage system.
5

Population trend for night soil treatment anddomestic wastewater treatment
Toilet140
Self-management ofnight soil

Outside area of administrative
manegement for night soilObject

Night soil storage tank use

OnlynightOn-site soil

120

Populationn (million perrsons)

Site

100

80

Vault and vaccum toilet use

60
Cistern flush toilet use

40

Nightsoil＋Off-site GreywaterSSewerage
use

200

Fyscal year

・Gappei-shori
Gappei-shori johkasou use includes Rural sewerage system use and Community plant use
use.
・Off-site include Sewerage system and Rural sewerage system.
6・Tandoku-shori jojkasou: 4.67 million units, Gappei-shori johkasou: 3.14 million units (asof the end of FY 2011)

Chronological developmentof onon-site systems～The World War II (1945)
S i l circumstances
Socialit・Night soil was used as a valuable fertilizer.
Technologies and systems
・Night soil was stored in a vault and traded for money or vegetables.
・Grey water was directly discharged to the nearby waterways.

7However・Recommendation of no-use by the Occupation Force to prevent parasitic
diseases・Spread use of cheep chemical fertilizers
etc.
1945～1955
1945～
Social circumstances
・Drastic decrease of night soil
use in agriculture
gHole for droppingof excreta

Illegal and/or unsanitary disposal of night soil
Technologies and systems
・Beginning of night soil treattreat
ment facility construction(Anaerobic digestion + supernatant treatment)8
http://www.okikou.or.jp/nagai_cc/nagai%20si.htm

Social circumstances
・Requirement of cistern flush toilet use
Technologies and systems
・Beginning of household type tandoku-shoritandoku shorijohkasou use・Grey
y water was still directly
y discharged
g tothe nearby waterways.

Japanese style
Jt lcistern flush toilet

BlowerDisinfection chamber

Sedimentation
Sdit tiseparation chamber

AerationchamberSedimentationchamber

An example of household type tandoku-shori johkasous
91955～1965
1955～
Social circumstances
・Start of economic development
・Urbanization and industrialization
・SpreadS
d off public
bli nuisanceiTechnologies and systems
Beginning of medium
medium- and largelarge
・Beginning
scale gappei-shori johkasou use
An example of medium-scale
gappei-shori johkasou

1985～1995
1985～
Social circumstances
・People's requirement of access to water environment
Technologies and systems
・Development of household type gappei-shori johkasou with the effluent BOD
concentration ≦ 20 mg/L10An example of household type gappei-shori johkasou

Diffusion pipe

Influent

Anaerobic
filter tank

Separatedsludge

Contact
aeration tank

Sedimentation
tank

SludgeEffluent water quality
BOD≦20 mg/L

DisinfectiontankEffluent11

1995～2005
1995～
Social circumstances
・Improvement in environmental standards achievement
・Request of cost down in installation of household type gappei-shori johkasou
Technologies and systems
・Standardization of advanced processes was introduced in gappei-shorijohkasou including household type12

An example of household type gappei-shori johkasou for BOD & N removal
Pi forPipe
f recirculation
il tiIntermittent pump

DisinfectiontankAnaerobic filter tank
(1st room)

Effluent water quality
BOD≦20 mg/L
T-N ≦20 mg/L

Anaerobic filter tank(2nd room)
Contact aerationtankDiffusing pipe

Sedimentation
tank

Recirculation

Influent

Anaerobic
filt tankfiltert kContactaeration
ti tankt kFlow equalization

Sedimentation
tank

SludgeDisinfection
t ktankEffluent

13

・Abolition of new installation of tandoku-shori johkasou
BOD load of night soil] : 13 g/cap.･d
BOD load of grey water: 27 g/cap.･dGappe-shori johkasou

Night soil

1 family:4 persons

Grey water

5.8 kg/fam.･yGappei-shorijohkasou

Total

Tandoku-shori jjohkasou
46.7 kg/fam.･yNight soil
Grey water

Effluent

Tandoku-shorijohkasou39.4 kg/fam.･yDischarged BOD load14

http://www.pref.kagoshima.jp/ah11/infra/toshi/haisui/zyokaso/joukasonohi.html

・Development of compact household type gappei-shori johakasou

Appearance of a standard household type gappei-shori johkasou(V l(Volumerequired
i d ffor ttreatmenttt isi aboutb t3
3.00 m3)Compact household typegappei-shori johkasou(V l(Volumerequired
i d ffor ttreattment is reduced to about
70% of the standard type.)15

2005～
2005～
Social circumstances
・Request of cost down in installation of household type gappei-shori johkasou
・Request of replace of tandoku-shori johkasou by gappei-shori johkasou
Technologies and systems
・Development of more compact household type gappei-shori johakasou(Volume required for treatment is reduced to about 50% of the standard type)Compact Tandoku-shori jtypejohkasou

An example of more compact household typegappei-shori johkasou for BOD & N removal

More compact
type

Plane figures of some johkasou

16Outlines of structural standards of johkasou(Treatment process, number of users for design anddesigned treatment performance)

Necessary jobs forproper use off johkasou
j hkInstallation
Operation ＆Maintenance(once every 4 months)

Desludging
g g(once a year)

Technologically, frequency of desludging
can be changed
g according
g to how to use
each johkasou (actual number of users,
applied effluent standard, etc.).

Inspection(after installationand once a year)

18

Framework of johkasou management
under the Johkasou Law
Johkasou manager(User and/or owner )(Number of usersfor design＞501)
Assignment

RequestExamination
Specifiedinspection agency
Agency: 65

Technical
supervisor

Registant: 1,210

Registant: 26,658

If a designated qualification is given by an examination or a short course,a johkasou manager canperform maintenance of
his johkasou.

Maintenance
E t
Entrustt

Desludging
E t
Entrustt

Johkasou maintenance vendor

Johkasoudesludging vendor

Vendor: 12,871
Registant: 72,521

Vendor: 5,375
Registant: 15,117

JohkasouJhk
manufacturer:f t
27
Johkasou installation vendor: 33,593, Johkasou installation worker: 83,205

19(Numbers are the data as of the end of FY 2010.)