Legal System of Decentralized Domestic Wastewater
Treatment Management in Japan including the Johkasou Act
19th December, 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/

Overall concept of water environment improvement and related legal framework

TargetEstablishment of Environmental Quality Standardsof Pollution 【Basic Environment Law】
・Establishment of Wastewater Standards【Water Pollution Prevention Act】
Nationwide uniform standards

Industrial
Wastewater
Measures・Stricter regulation on Wastewater Standards
・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.

National Government- Vision- Law & Regulations- Technical Standards- National Subsidies
Sharing Responsibility
Local Government- Treatment Master plan andits implementation- Ordinance- Construction, Operation andManagement of seweragefacilities- Advice and guidance on
Johkasou operation andmaintenance2

Johkasou Act
 Purpose Strengthen regulations of manufacturing, installation, operation, maintenance and desludging of Johkasou.
 Provides qualifications for Johkasou installation workers and operators
 Provides registration systems for Johkasou installation vendors and maintenance vendors
 Provide licensing systems for desludging vendors
Promotion of domestic wastewater treatment by Johkasou for conservation of water quality in public water
area, preservation of the living environment and improvement of public health Definition Johkasou is the decentralized wastewater treatment facility that can treat both black water and grey waterfrom household, building and so on and discharge effluent comply with effluent standards.
 Johkasou should be installed when installing a flush toilet under the Building Standard Law, unless thewastewater is discharged to sewerage systems.

 Related Laws

Johkasou Act
Enacted in 1983

Enforcement
Ordinance

Enforcement
Regulations

Define the scale of Johkasou which
need Johkasou Operators etc.

Define the period of inspection,
desludging or the technicalstandard of desludging etc.

3Outline of Articles 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)(Articles on wastewater treatment anddesludging)
Johkasou operators(articles 45–47)
Registration of maintenance and inspection
vendors (article 48)

Ministry of Land,
Infrastructure,
Transportation
and Tourism(MLIT)(Articles on construction standards)
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)
4

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 testmanufacturing) This process is suitable to Performance Evaluation System
Approval by the
Minister of Land,Infrastructure,Transportand Tourism

Performance
Evaluation Test

ModelApproval byJohkasou Act

Inflow

Outflow
Disinfection

Sedimentation
tankAnaerobic
filter tankMovingbed tank
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
5Inspection and Maintenance of Johkasou

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

6Registration process and qualifications system
National qualifications

Prefecture

Municipality

Registration
Instructions, advice,recommendations,etc.

【Certified Johkasou Installation Worker 】
Person certified to supervise Johkasou
construction
Johkasou construction
company

Approval
Instructions, advice,recommendations,etc.

Johkasou desludging
company

Registration

Prefectureor other

Instructions, advice,recommendations,etc.

【Certified Johkasou Operator】
Person certified to supervise Johkasou
maintenance inspections
Johkasou maintenanceinspection company

7

Training courses for Johkasou technicians 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 Operator
by Article 45

Johkasou Installation Worker
by Article 42

 Fundamental of johkasou
8H Laws and regulations related with johkasou 4 H
 Structure and function of johkasou
22 H
 Introduction to installation of johkasou
4 H
 Operation and maintenance of johkasou 30 H
 Water quality management of johkasou
10 H Introduction to desludging of johkasou
2H

 Fundamental of johkasou
8H Laws and regulations related with johkasou 3 H
 Structure and function of johkasou
15 H
 Management of johkasou installation
8H
 Introduction to O&M and desludging of johkasou
3H

Total

80 Hours(13 Days)+Test
2 Hours

Total

37 Hours(5 Days)+Test 2Hours
8

THANK YOU FOR YOUR KIND ATTENTION.

At Kikuchi Gorge,Kikuchi City,Kumamoto Prefecture