Mechanisms of Johkasou Act
28th November, 2023

Mr. Ryoma SATO
Section Chief, Office for Promotion of Johkasou

Office for Promotion of Johkasou
Waste Management Division
Environmental Regeneration and Material Cycles Bureau
Ministry of the Environment
Government of JAPANhttps://www.env.go.jp/recycle/jokaso/

TABLE OF CONTENT

Chapter 1: General Information of Johkasou in Japan

Chapter 2: Legal Framework of Johkasou in Japan2

1. General Information of Johkasou in Japan Wastewater Treatment Systems in Japan
Johkasou
浄化槽
installedarea（既整備区域）

Collective Rural
集落排水
Wastewater Facilities（未整備区域）
un-installed area

Sewage system
下水道

un-installed area

（未整備区域）

Collective Rural
集落排水
Wastewater Facilities（既整備区域）
installed area

TT

Sewage system
下水道（既整備区域）
installed area

Johkasou
浄化槽
un-installedarea（未整備区域）

 Sewage System : managed by the Ministry of Land, Infrastructure, Transport and Tourism
 Collective Rural Wastewater Facilities : managed by the Ministry of Agriculture, Forestry andFisheries
 Johkasou: managed by the Ministry of the Environment3

1. General Information of Johkasou in Japan
 Current situation of population served for treating domestic wastewater by different wastewater
treatment facilities in Japan
Type of treatment facility

Population served(x 1,000 people)
End of FY2022

End of FY2021

101,280 (81.0%)

101,181 (80.6%)

including Facilities for fishing villages, Facilities for forestry
villages, Simple wastewater facilities

3,018 (2.4%)

3,103 (2.4%)

Johkasou

11,784 (9.4%)

11,758 (9.4%)

Municipal Johkasou Installation Program

825

831

Johkasou Installation and Maintenance Program

6,229

6,203

Other Johkasou

4,730

4,725

160 (0.1%)

171 (0.1%)

Total population served

116,242

116,213

Percentage of population served

92.9%

92.6%

Total population

125,065

125,540

Total population not served

8,823

9,327

Un-installed rate

7.1%

7.4%

Municipal sewage systems
Collective rural wastewater facilities,

Community plants, etc.

4

1. General Information of Johkasou in Japan
 “Johkasou” is categorized as decentralized wastewater treatment system for domestic wastewater discharged
by household, building and so-on.“
 Johkasou have a combined purification structure capable of treating both night soil (black water) andmiscellaneous wastewater (gray water)
 Johkasou attains high and stable performance as same as that of sewage treatment plant and it has been
installed totally more than 3.9 million unit in Japan.

Industrial wastewater, Domestic wastewater
Domesticwastewater

Sewage treatment, Decentralized treatment
Septic tank, wetland,DEWATS, etc., Johkasou

Clean,
purifiedwater

BOD removal, Nitrogen and/or Phosphorous removal
Johkasou
Usually installed undergroundTypical layout of small scale Johkasou setup for household

51. General Information of Johkasou in Japan Domestic wastewater = Black water (Night soil) + Gray water(kitchen drainage, bath drainage etc.)
Current Johkasou in JapanCurrent
JohkasouBoth Black water & Gray water are treated.

Lessimpact withlow
pollutantload

Publicwaterway

Old type Johkasou in Japan
Only Black water is treated and have lowtreating ability⇒ Heavy impact with 8 times pollutant load

OldJohkasou

Heavy impact
with 8 times
pollutant loadWithouttreatment

In Japan, old type Johkasou are treatedas untreated domestic wastewater.
Discharge of untreated wastewater6

1. General Information of Johkasou in Japan
 Configuration of old & current type Johkasou

Number of Johkasou installed(person)

 Though new installation of old type Johkasou was prohibited in 2000, still approx. 3.6 million sets of oldtype Johkasou are used in Japan.
 It is necessary to promote the conversation to the current type of Johkasou.

Johkasou Act
enactedNational subsidy
program for Current
type Johkasou
established (forindividuals)

Total numbers ofJohkasou
installed :7,527,615

New installation of old type
Johkasou was prohibited
except in special cases

Old Type Johkasou
3,569,862(47.4% of total)

Old typeCurrent typeCurrent TypeJohkasou
3,957,753(52.6% of total)

▲
1985

▲
1990

▲1995▲
2000▲
2005▲
2010

▲
2015▲
2020 (year)71. General Information of Johkasou in Japan Comparison chart of Sewage, Johkasou and Septic tank
Sewage（STP)
Category

Centralized

Capacity(m3/day)Large

Application

City covering with pipeline
networkJohkasouSeptic tankDecentralized

Small to middle

Small

For household, building, housing complex, community,hospital, school, public toilet, etc.

TargetBlack water (Toilet) & Gray waterBlack water

MethodAerobic (plus Anaerobic)

Anaerobic only

Treated water
quality- Good- BOD <20mg/L- Nitrogen & Phosphorous can be removed- Poor, BOD ≓ 100mg/L- Nitrogen and Phosphorous
can’t be removed

Discharge

Clean discharge is discarded directly to the river, lake,sea and so-on.

- Dirty discharge is penetrated
into ground- Gray water is discarded
without treatment

Main body

Civil structure constructed
at siteCivil structure constructed atsite

Maintenance works
Total period for
operation start

FRP manufactured infactory

Checking and adjustment, desludging, inspection,changing spare parts
Long for planning, financing,construction

Desludging only
(every 3 to 5 years)
ShortJohkasou can be recognized as a “prefabricated small scale sewage treatment plant” in wastewater management81. General Information of Johkasou in Japan Application of Johkasou for domestic wastewater management(Ex. Poverty houses where frequent waterborn diseases are infected)f) Monumental Area

(Ex. For natural reserve, world heritage, etc.)

 Example of Johkasou installation overseas

Restaurant(China: 10m3/d)

Toilet in factory(Vietnam: 5m3/d)Canteen & toilet(Myanmar: 30m3/d)

Employee dormitory(Saudi Arabia: 530m3/d)

At the end of 2022, totally over 50,000 sets of Johkasou are installed overseas

91. General Information of Johkasou in Japan
 Installation records in Overseas (Total)
United Kingdom ◇S 57units

India ◇S 123units, ◆M/L 379units

Pakistan ◇S 4units ◆M/L 1units

Nepal ◇S 1unit, ◆M/L 4units◇S 2units

Vietnam ◇S 930units, ◆M/L 530units

Germany ◇S 370units
GreeceBangladesh ◇S 22units, ◆M/L 24units◇S 10units

Myanmar ◇S 756units, ◆M/L 274units

Hungary ◇S 3units

Thai ◆M/L 4units

Romania ◇S 209units
Italy◇S 11units

Taiwan ◇S 1unit, ◆M/L 1unitPhilippines ◇S 36units◆M/L 5units

Mali ◇S 1unit
Arab◇S 3unitsSouth Africa ◇S 45units

Saudi Arabia ◇S 6units◆M/L 1unit

Mozambique ◇S 1unit

Palestine ◇S 1unit

Tanzania◆M/L 1unit

Syria◆M/L 1unit

Kenya◇S 157units◆M/L 12units

Iraq◆M/L 2unit

Mauritius◇S 1unit

Korea◆M/L 1unit

Total 51 countries

Panama ◆M/L 1unit
Grenada ◇S 1unit

Sri Lanka ◇S 370units◆M/L 174units

Nigeria ◇S 16units◇S 1unit

Honduras ◇S 1unit
Costa Rica ◇S 2units

Laos ◇S 2units, ◆M/L 4units

Lybia◆M/L 3units

Small size 48,325units
M/L size 1,856units
Total 50,181units

Mexico ◇S 15units

China ◇30,314units, ◆M/L 18units

Algeria◆M/L 8units

Egypt

USA ◇S 6,551units, ◆M/L 19units

Oman ◇S 204units
Jordan ◇S 6units
Iran◇S 1unit Trend by years (Total)

Palau ◇S 17units, ◆M/L 3units
Malaysia ◇S 1unit
Singapore ◆M/L 4units

Papua
New Guinea◆M/L 1unit

Indonesia ◇S 200units,◆M/L 341units
Australia ◇S 7,832units, ◆M/L 39units
Kuwait◇S 2unit

Yellow colored : more than 100units◇S： Small-scale ( 5 PE ～ 50 PE)◆M/L ： Medium/Large-scale ( 51 PE ～ )Accumulated numbers

RussiaAs of the end of December 2022 (Total) by Johkasou System Association

Around
1.6timesin 3 years102. Legal Framework of Johkasou in Japan Overall concept of water environment improvement
National Government

TargetEstablishment of Environmental Quality Standardsof Pollution 【Basic Environment Law】

・Establishment of Wastewater Standards- Vision- Law & Regulations- Technical Standards- National Subsidies

・Stricter regulation on Wastewater Standards

Sharing Responsibility【Water Pollution Prevention Act】
Nationwide uniform standards

Industrial
Wastewater
Measures・Regulations on business operators【Water Pollution Prevention Act】
Notification, measuring and recording ofwastewater, on-site inspection→ Penalties, improvement orders and otheradministrative guidances

・Investments, human resource developments, etc.
for pollution prevention

Domestic
Wastewater
Measures・Sewerage System Establishment 【Sewerage Law】
・Installation of Johkasou 【Johkasou Act】 etc.

Local Government- Treatment Master planand its implementation- Ordinance- Construction, Operationand Management ofsewerage facilities- Advice and guidance on
Johkasou operation andmaintenance11

2. Legal Framework of Johkasou in Japan History of Johkasou Act
Year

Item

1960 toWith increasing population of flush toilet, rapid installation of Tandoku (old type) Johkasou to treat blackaround 1980 water only

1983

Johkasou Act enacted (legislation introduced by a Diet member, came into force in 1985)

2000

Amendment: New installation of Tandoku-shori (old type) Johkasou was prohibited

2005

Amendment: Stricter water quality management systems introduced

2019

Amendment: Strengthening the authority of prefectural governors for conversion from Tandoku
Johkasou (old type) to Gappei Johkasou (current type) Clarification for proceeding Johkasou installation as a public works
 Others

 Purpose of Johkasou Act
 Promotion of domestic wastewater ( both black and gray water ) treatment by Johkasou for conservation ofwater quality in public water area
 Preservation of the living environment
 Improvement of public health122. Legal Framework of Johkasou in Japan
 Structure of Johkasou Act

1) Johkasou’s manufacture and sales
2) Johkasou’s notification of installation
3) Johkasou’s installation and certification system of installation engineer
4) Johkasou’s report of start date to use
5) Johkasou’s operation
6) Johkasou’s water quality inspection after installation
7) Johkasou’s maintenance and certification system of maintenance engineer
8) Johkasou’s desludge (Cleaning)9) Johkasou’s periodical check10) Penalties for violating the Johkasou Act13

2. Legal Framework of Johkasou in Japan
 Outline of each article from 1 (one) to 68 (sixty eight) and its jurisdiction in Johkasou Act
Ministry of theEnvironment(MOE)

General provisions (articles 1– 4):
Purpose/definitions
Johkasou installation(articles 5–7)

Johkasou operations/maintenance(articles 8–12)
Approval for johkasou desludging vendors(articles 35–41)

Ministry of Land,Infrastructure,Transportation
and Tourism(MLIT)(Articles on construction standards)(Articles on wastewater treatment anddesludging)
Johkasou operators(articles 45–47)
Registration of maintenance and inspection vendors(article 48)

Approval for types of johkasou(articles 13–20)
Registration for johkasou construction vendors(articles 21–34)
Johkasou Installation Workers(articles 42–44)

Miscellaneous provisions(articles 49–58)
Penalties(articles 59–68)
14

2. Legal Framework of Johkasou in Japan Approval process for types of Johkasou (Johkasou Act, Article 13)
 Parties intending to manufacture Johkasou in production plants shall obtain approval from the Ministry of Land, Infrastructure,
Transport and Tourism (MLIT) for the type of Johkasou to be manufactured (does apply to test manufacturing) This process is suitable to Performance Evaluation System
Approval by the
Minister of Land,
Infrastructure,Transportand Tourism

Performance
Evaluation TestModel
Approval byJohkasou Act

Inflow

Outflow
Disinfection

Sedimentation
tankAnaerobicfilter tankMoving bedtank

Sedimentationtank

Put into
MarketPerformance
Ensured Johkasou’s
Performance
Evaluation System Detail of Johkasou’s
Performance
Evaluation System

https://www.bcj.or.jp/upload/rating/bizunit/hyoutei/joushi_hyoukahouhou.pdf

Sample of Performance Evaluation Type Johkasou
15

2. Legal Framework of Johkasou in Japan Example of contents in Johkasou’s Performance Evaluation System
30

Performance Criteria
Applicant (Johkasou manufacture) chooses
the application value for test criteria in below

Inflow ratio （％）1)2) Inflow Pattern

BOD [20, 15, 10, 5 ], T-N [20, 15, 10, 5 ], T-P [2,1,0.5,0.1 ]SS [20, 15, 10, 5 ], n-Hex [20, 10, 5, 3 ], COD [30, 15, 10 ]252015105013) Type of Performance Evaluation Test
Test Method

Duration (weeks)

Short period constanttemperature

Breeding - over 16 wks（13 & 20℃ 8 wks respectively）

No. ofunit
1 or 2

Breeding＋over 48 wks

Over 1

On-site test 2

Breeding＋over 48 wks

Over 3

Duration (weeks)No. ofunit

Test Method579

11 13 15 17 19 21 23

Times of DayTime

On-site test 14) Other Test

3Evaluation Points
Water Quality/Sludge/Maintenance
Water Quality/Sludge/
Maintenance
Water Quality/Sludge/
MaintenanceEvaluation Points

Maintenance evaluation
Over 1Ease of Maintenance
test
Over 1
SludgeSludge test
Breeding＋over 12 wks
Note: In order to obtain approval, several tests are implemented in combination in the above tables.

162. Legal Framework of Johkasou in Japan Johkasou Installation Procedure and related Article of Johkasou Act
Installation notification (Article 5)(Certify under the Building Standards Act when necessary)••

Construction (Article 6)Johkasou contractor must register with the prefectural governor (Article 21)
Johkasou contractor must dispatch the certified installation technician oneach office (Article 29)(Can issue administrative recommendations when necessary)

Post-installation legal inspections (Article 7)～～
Discontinuance notification (Article 11-2)

17

2. Legal Framework of Johkasou in Japan
 JIS A3302-2000 Estimation of population for wastewater purifier of buildings
1 P.E. = 200L/day, 40g BOD/day
Example General household【Equation】 If total floor area A (m2) ≦130m2 , Johkasou capacity (P.E.) shall be 5 P.E.
 Hotel with a wedding hall【Equation】 Johkasou capacity (P.E.) = 0.15 ｘ ( total floor area A (m2) ) Large hospitals with commercial kitchens or laundry facilities and more than 300 beds
【Equation】 Johkasou capacity (P.E.) = 11.43 ｘ (number of beds B - 300) + 2,400
Large categories

Detail categories(Equations)

Large categories

Detail categories(Equations)

1. A place where people gather

Theater, etc. (3)7. Parking

Highway rest area, etc. (7)2. Residence

Apartment, etc. (6)8. School

Library, etc. (3)3. HotelMotel, etc. (4)9. Office

Office with canteen, etc. (2)4. Medical facility

Clinic, etc. (5)10. Work facility

Laboratory, etc. (2)5. Store

Restaurant, etc. (6)11.Others

Public toilet, etc. (6)6. Amusement facilities

Disco, etc. (13)Total 11 large categories, 57 equations18

2. Legal Framework of Johkasou in Japan・ Post-installation water quality inspection (Article 7)
Inspection category

Visual inspection

Inspection items
・Installation status

・Usage status

・Operational status

・Foul odors

・Water flow

・Use of disinfectant

・Mosquitoes, flies, etc.

Water quality inspection

・Hydrogen ion concentration

・Chlorine ion concentration

・Sludge settling ratio

・Residual chlorine concentration

・Transparency

・Biochemical oxygen demand

・Dissolved oxygen
Document inspection

・Pre-usage maintenance inspection record

 Because essential johkasou functions cannot be confirmed without actually using the equipment, inspections are carried out once
those functions are generally up and running. Inspections focus on whether the johkasou is performing the expected treatment
functions with the aim of rectifying any deficiencies as soon as possible.
192. Legal Framework of Johkasou in Japan
 Inspections and Maintenance

MOEJ “Night Soil Treatment and Decentralized Wastewater Treatment System in Japan”

20

2. Legal Framework of Johkasou in Japan Johkasou corporate registration process【Certified Johkasou Installation Worker 】
Person certified tosupervise Johkasou construction

Registration

Prefecture

Municipality

Instructions, advice,recommendations, etc.

Johkasouconstruction
company

Approval
Instructions, advice,recommendations, etc.

Prefectureor otherNational qualifications

Johkasoudesludging
company【Certified Johkasou Operator】
Person certified tosupervise Johkasou maintenance inspections

Registration
Instructions, advice,recommendations, etc.

Johkasoumaintenanceinspection company
21

2. Legal Framework of Johkasou in Japan

National johkasou qualifications
Nationalqualification

Description

Certified Johkasou
Installation Worker

Person certified to supervise johkasou
construction

Certified Johkasou
Operator

Person certified to carry out maintenanceinspections on johkasou

Certifying agency

22

2. Legal Framework of Johkasou in Japan
 For Johkasou Technicians by Japan Education Center of Environmental Sanitation (JECES) Johkasou technicians should acquire extensive knowledge on not only wastewater treatment/johkasou,
but also water environment conservation and public health.
 Curriculums for johkasou operator and johkasou installation worker are as shown below.

Johkasou Operatorby Article 45





Johkasou Installation Workerby Article 42

Fundamental of johkasou
Laws and regulations related with johkasou
Structure and function of johkasou
Introduction to installation of johkasou
Operation and maintenance of johkasou
Water quality management of johkasou
Introduction to desludging of johkasou
Total

8 H
4H
22 H
4 H
30 H
10 H
2 H

80 Hours(13 Days)

Fundamental of johkasou
Laws and regulations related with johkasou
Structure and function of johkasou
Management of johkasou installation
Introduction to O&M and desludging of johkasou
Total

8H
3H
15 H
8H
3H
37 Hours(5 Days)+Test 2 Hours+Test 2 Hours

23

THANK YOU FOR YOUR KIND ATTENTION.

At Kikuchi Gorge,Kikuchi City,Kumamoto Prefecture