Decentralized Treatment
for Domestic Wastewaterusing the Johkasou System
Pierre Flamand

Manager – International affairs
Japan Sanitation Consortium

Shinhi Kumokawa

Japan Education Center of Environmental Sanitation

Contents
1.

History of sanitation improvement in Japan

2. Johkasou technology
3. Legal system and measures for decentralized
treatment
4. Examination/training system for johkasou technicians
5. Japan’s experience on decentralized domestic
wastewater treatment

1. History of sanitation improvement in Japan1. History of sanitation improvement in Japan•

In the beginning of the 1900s, to prevent theoutbreak of waterborne diseases, wastewater fromtoilets could not be discharged to the environment
by law, unless it was treated by a designated methodwith the assurance that the treated water was freeof hygienic problems.
The situation remains unchanged after that time.

•

In the 1920s, a “Filth treatment tank,” which is a septic tank combined with a trickling
filter, was developed to treat wastewater from toilets. It was originally using Japanesecharacters and is the forerunner of today’s Johkasou.

•

In 1950, the Structural Standards for Sewage Treatment Tanks (Johkasou) were stipulated.
Septic tank, Imhoff tank and some aeration processes were introduced in the standards.
Johkasou made of RC gradually spread from then. As the number of installed johkasou
was small, the maintenance of johkasou was usually conducted at that time bytechnicians from johkasou manufactures. However, the desludging of johkasou wascarried out by the workers of local vendors who, for generations, did the job of removing
human waste from vault toilets.
4

1. History of sanitation improvement in Japan～2nd World War(~1945)
Social Background
Night soil is valuable and usedas fertilizer in rural areas
Treatment/disposal of night soil
 Farmers buy night soil from residents
by rice and vegetables.
 Gray water was discharged into gullies
nearby.

5

1. History of sanitation improvement in Japan
1945～1955
 Social Background・Decrease of use of night soil in agriculture due tothe spread of cheap chemical fertilizer
Social needs for hygienic treatmentof night soil
Japanese Vault toilet

 Treatment/disposal of night soil
 Start to constructing night soil
treatment facilities nationwide.
 Anaerobic digestion process was
popular.

A night soil treatment facility built in the1950s

1. History of sanitation improvement in Japan• In the early 1960s, with the improvement of living standards along with the higheconomic growth, strong demands for flush toilets emerged.
• At that time, vault toilets were popular in houses, which necessitated to remove
the night soil storied in tanks every 3-4 months by vacuum trucks and totransport it to night soil treatment facilities for sanitary treatment.
• When flush toilets were introduced, vault toilets could not be used anymore as
it would be full of wastewater in a short period of time and the night soil
collection/transportation system could not deal with it due to limited capacity.
• A treatment plant designed for the treatment of individual household
wastewater from flush toilets and the discharge of the treated effluent to theenvironment was proposed .
• The improvement of the produced technology enabled the mass-production ofhousehold johkasou (Packaged Aerated Wastewater Treatment Plants-PAWTPs).
This resulted in the explosive spread of johkasou.

FRP-made johkasou in the 1960s

7

1. History of sanitation improvement in Japan1960～
 Social Background・Huge demands for flush toilets
 Treatment technology
・R&D of household wastewater treatment facility(tandoku-shori johkasou )・Gray water discharged into public water bodies

Japanese flush toilet

Tandoku-shori johkasou for treatment of wastewaterfrom flush toilets （Effluent BOD 90 mg/L）

8

1. History of sanitation improvement in Japan
1955～1965
 Social Background・High economic development phase・Industrialization and urbanization
 Treatment technology
・Medium/larger scale johkasou wasdeveloped and was put into market

1985～1995
 Social Background・Increasing awareness of environment conservation
 Treatment technology
・Household johkasou with high treatment performance was developed
and was put into market. （effluent BOD < 20 mg/L）
9

2. Johkasou technology

Johka-sou
Johka = purification
sou =
tank
(in Japanese)11リレーションシップ ID rId3 のイメージ パーツがファイルにありませんでした。

Water Pollution by Untreated Domestic WastewaterHigh public healthrisks (pathogenic
microorganisms)

Adverseenvironmental
impacts

Pollutant loads (BOD) of domestic wastewater

Daily amount of domestic wastewater

Water pollution by untreated grey water
12

Pollutant Loads for Johkasou Design

Pollutant Loads for one PE (Person Equivalent)
13

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

14

Structures and Treatment Performances of Johkasou

15

Johkasou classified by treatment capacity
 Small-scale johkasou:

5 to 50 PE, or the average amount ofwastewater less than 10 m3/day.

 Medium-scale johkasou: 51 to 500 PE, or the average amount ofwastewater less than 100 m3/day.
 Large-scale johkasou:

501 PE or more, or the average amountof wastewater more than 100 m3/day.

For Residential

For Commercial

For Community/village

16Treatment Principles of Johkasou

17

Influent

Disinfection
Chamber

Storage Chamber

Aerobic Filtration
Chamber

Anaerobic
Filtration Chamber

Sedimentation
Chamber

An Example of Small-scale Johkasou (FRP)

Recirculation Water(Air-lift Pump)

Overflow

Effluent18

A Johkasou for BOD & N&P Removal
Device for phosphorous removal
リン除去装置＜槽外設置＞

Controler【制御ボックス】【防水コンセント】【電源ケーブル】

Cell base＜槽内設置＞

Relay box
防水コネクタConnecters【中継ボックス】

Cell
base

【セル】

固定
Bolts

Cell
base
セルベース

ボルト
鉄電極
Electrodes

Effluent water quality
BOD <=10 mg/L
T-N <=10 mg/L
T-P <= 1 mg/L

19

A Small-scale Membrane Johkasou

Effluent water quality
BOD <= 5 mg/l
T-N <=10 mg/l

This membrane johkasou could be applied to areas where reuse of treated water is a matter of high priority
because of water shortage.
20

Innovation of Johkasou Technology
contact aeration
process

 Downsizing of johkasou by
Introduction of new biological treatment processes① Moving bed biofilm process;② Biofilm filtration process; and③ Moving bed biofilm-filtration process,instead of traditional contact aeration process
Product of the year 2000:
L 2,790mm; W 1,140mm; H 1,750mm
64% DOWN
in space

①

②

③
21

Innovation of Johkasou Technology
 Reduction of energy consumption by① Development of energy-saving blowers；

Energy consumption of blower(W)② Introduction of intermittent aeration operation
120

Type1 (60 L/min) for 5PE

100

Type2 (80 L/min) for 7PE

80
60
40
20

Energy consumption of a new
type johkasou of 5PE, which isoperated in intermittent aerationmode, is only 0.6 kWh/day.

●

0
1984

1990

2006

2015
22

3.

Legal system and measures fordecentralized treatment23

3. Legal System for Decentralized Treatment – Johkasou Act
History of Johkasou Act
1960 to around 1980

With increasing population of flush toilet, rapid installation of tandoku(old type) johkasou to treat black water only

1983

Johkasou Act enacted (legislation introduced by a Diet member, cameinto force in 1985)1987

National subsidy program for gappei (current type) johkasou (to treat
both black and gray water) established

2000

Revised: New installation of tandoku-shori johkasou systems basicallyprohibited2005

Revised: Stricter water quality management systems introduced,
defining water quality conservation targets

During high economic
growth period, waterpollution accelerated.

To promote the spread of
gappei johkasou and thereplacement of tandoku
johkasou systems

Purpose of Johkasou Act
Promotion of human waste and gray water treatment by Johkasou for;- Conservation of water quality in public water area, preservation of the living
environment and improvement of public health⇒Articles in Johkasou Act①Johkasou installation（※related to “Building Standard Law”）②Operation/maintenance of Johkasou③Approval of Johkasou models④Johkasou business for Installation and Operation/Maintenance⑤Nationally qualified “Johkasou technicians”⑥Miscellaneous and penalties24

3. Legal System and Measures for Decentralized Treatment
Ministry of theEnvironment

General provisions (Articles 1–4): Purpose/definitions

Ministry of Land,
Infrastructure,
Transport and Tourism

Johkasou installation (Articles 5–7)
Johkasou operations/maintenance (Articles 8–12)
Approval for johkasou desludging vendors (Articles 35–41)(Articles on construction standards)
Approval for types of johkasou (Articles 13–20)(Articles on waste treatment and desludging)

Registration for johkasou construction vendors (Articles 21–34)

Johkasou operators (Articles 45–47)

Johkasou installers (Articles 42–44)

Registration of maintenance and inspection vendors (Article
48)

Miscellaneous provisions (Articles 49–58)

Penalties (Articles 59–68)
25

3. Legal System and Measures for Decentralized Treatment

Water quality standards (Article 4-1)
Technical standards for discharged water quality
o Water discharged from gappei-shori johkasou must have a biochemical oxygen demand(BOD) concentration of 20 mg/L or lesso (Influent BOD – effluent BOD) ÷ influent BOD ≥ 0.9* Comparable to the treatment level of modern sewerage treatment plants(Johkasou Enforcement Ordinance Article 1-2)

 The above regulations were created to reflect current technological standards in light of best
available technologies (BAT) or best available techniques not entailing excessive costs(BATNEEC) according to the development and spread of johkasou.

26

3. Legal System and Measures for Decentralized Treatment
・ Johkasou Installation Procedure
Installation notification (Article 5)(Certify under the Building Standards Act when necessary)
Construction (Article 6)(Can issue administrative recommendations when necessary)

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

27

3. Legal System and Measures for Decentralized Treatment
・ Approval process for types of Johkasou (Johkasou Act Article 13)•

Parties intending to manufacture Johkasou in production plants shall obtain approval
from the Minister of Land, Infrastructure, Transport and Tourism (MLIT) for the type ofJohkasou to be manufactured (does apply to test manufacturing).
This process is subject to Performance Evaluation System.

•

Performance
Evaluation
Test

Approval by the
Minister of Land,
Infrastructure,
Transport and Tourism

Model
Approval by
Johkasou Act

Put into
MarketPerformance
EnsuredInflow ratio （％）

30

Inflow

25

Outflow

20
15

Disinfection

10
5

Sedimentation
tank

0
1

3

5

7

9

11 13 15 17 19 21 23

Anaerobic
filter tankMoving bed
tank

Sedimentation
tank

Time

Inflow Pattern

Performance Evaluation Type Johkasou
28

3. Legal System and Measures for Decentralized Treatment
４．性能評価型
・ Structural Standard vs Performance Evaluation System
・ Structural Standards for Johkasou
Construction Minister (then) stipulated Structural Standards in1969--- treatment methods and performance.
・Performance Evaluation System
Utilizing Performance Evaluation System operated from 2000,
manufacturers competed for compactness and higher performance.
Downsizing for home use and technology for higher treatment.
Initial Type：70% downsized-content Johkasou appeared.
・To regulate water level at initial treatment to control flow capacity--- additional pump and maintenance of air-lift are necessary.
・Bio-film filtration or Moving bed type for secondary
treatment.
・Solid-liquid separation by Bio-film or Moving bed plus
automatic backwash.
--- Blower equipped with valve change timer is necessary.

Requested by households with several Johkasou to ease themaintenance, compact Johakasou without flow-control/automatic
backwash, with only one pipe from blower are on the increase.
29

3. Legal System and Measures for Decentralized Treatment

・ Flow of Evaluation System
Performance Evaluation Test （approx. 6 months）
・・・ by The Building Center of Japan↓
Application for Performance Evaluation Test（test result,technical data & drawings)↓
Evaluation by Special Committee↓
Issuance of Performance Evaluation Document↓
Approval by the MLIT Minister and for Model Adaptation↓
Model Approval by Johkasou Act and application forregistration (in case for the subsidy of ≦ 10 persons)↓
Put into the market

30

3. Legal System and Measures for Decentralized Treatment
・ Test methods and Criteria

1) Performance Criteria
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]2) Test Categories and Duration
Sludge may be added in case of ①
Category

Test Method

Duration (weeks)No. ofunit

Evaluation Points

1 or 2

Water Quality/Sludge/
Management①

Short period
constant
temperature②

On-site test 1

Breeding＋over 48
weeks

1

Water Quality/Sludge/
Management③

On-site test 2

Breeding＋over 48
weeks

3

Water Quality/Sludge/
Management

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

31

3. Legal System and Measures for Decentralized Treatment
・ Inspections and Maintenance32

3. Legal System and Measures for Decentralized Treatment

・ 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.
33

3. Legal System and Measures for Decentralized Treatment

Sludge collection, transport and treatment (Waste Disposal Act)

Collect andtransport
Johkasoudesludging

Night soil (black
water) treatment
facility

Collection and transport
Municipalities shall, in line with their general waste treatment plans, collect and transportjohkasou sludge (general waste) in a manner that poses no threat to the maintenance of
healthy living environments or public health, and treat the sludge at a black water
treatment facility(Article 6-2 of the Waste Management and Public Cleansing Act)34

3. Legal System and Measures for Decentralized Treatment
・ Johkasou corporate registration process
Prefecture

Municipality

Johkasouconstruction
company

Approval
Instructions, advice,recommendations, etc.

Prefecture
or other【Certified Johkasou Installer】
Person certified to supervise johkasou
construction

Registration
Instructions, advice,recommendations, etc.

・ National qualifications

Johkasoudesludging
company【Certified Johkasou Operator】
Person certified to supervise johkasou
construction

Registration
Instructions, advice,recommendations, etc.

Johkasoumaintenanceinspection company

35

3. Legal System and Measures for Decentralized Treatment

National johkasou qualifications
National
qualification

Description

Certified Johkasou
Installer

Person certified to supervise johkasou
construction

Certified Johkasou
Operator

Person certified to carry out maintenanceinspections on johkasou

Certifying agency

36

4. Examination/training system forjohkasou technicians37

Education history of johkasou technicians• The spread of johkasou in 1960s resulted in a huge shortage of johkasou
technicians, such as installation workers, O&M operators, desludging
workers and inspectors.
• To meet the demand for johkasou technicians and establish an education
system of johkasou technician as permanent measure, Japan Johkasou
Education Center, the precursor of JECES, was founded in 1966, with thesupport of administrations and johkasou related organizations.
• From then, technical training system for on-site wastewater treatment
was established, and it has been developed along with the johkasou
industry.

38

38

Education history of johkasou technicians•

When JECES started in 1966, two training courses were launched; A course for O&M
technician, and B course for desludging technician. A course for johkasou installation
worker in 1972, and a course for johkasou inspector in 1980, were launched.

•

The technicians trained through these training courses were succeeded by the Johkasou
Act later and were certified as Johkasou Installation Worker, Johkasou Operator,
Johkasou Desludging Technician and Johkasou Inspector, respectively.

•

When Johkasou Act was enacted in 1983, a new course for johkasou technical supervisor,
whom is required by the law for management of johkasou larger than 500PE, was created.

•

In 1984 and 1985, national examination for Johkasou Operator and Johkasou Installation
Worker started, these two certification can be obtained by passing the examination or byreceiving the training course.

•

JECES has been conducting the examinations and training courses, and trained various
johkasou technicians more than 3000 persons every year, as shown below.

39

39Features of the training system for techniciansof decentralized wastewater treatment
1. Position of the certifications in the Act
Johkasou Installation Worker
Article 42(1)(ii), Johkasou Act
Johkasou Operator
Article 45(1)(ii), Johkasou Act
Johkasou Technical Supervisor
Article 10(2), Johkasou Act
Johkasou Desludging Technician
Article 11(iv), Ordinance of Johkasou Act
Johkasou Inspector
Article 5(1)(iv), Ordinance of Johkasou Act
2. Business content of the certifications
As shown in the right figure.
•

These regulations make the certifications to be indispensable for persons who want to join thejohkasou businesses, and give incentives to them.

•

The certifications could be obtained by receiving training courses or passing national examinations.

•This training and certification system has played an essential role to enhance the technical level ofjohkasou technicians, and contributed to the appropriate spread of johkasou.
40

Features of the training system for techniciansof decentralized wastewater treatment
Employment

Training course
Examination

Johkasou Installation
WorkerJohkasou Operator

Employment

Procedures and relations of johkasou operator/johkasou installation worker in Johkasou Act
41

Features of the training system for techniciansof on-site wastewater treatment
Feature 3 : Working-level contents of curriculums for johkasou businesses• Johkasou technicians should be equipped with extensive knowledge on not only
wastewater treatment/johkasou, but also water environment conservation and publichealth.
• Curriculums for johkasou operator and johkasou installation worker are as shown below
Johkasou operator








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

Johkasou installation worker
8H
4H
22 H
4 H
30 H
10 H
2 H







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

80 Hours

42

Features of the training system for techniciansof decentralized wastewater treatment
Feature 4 : Follow-up to johkasou technicians and continuing professional development•

Support the johkasou technicians by providing updated technical information onjohkasou, and give them appropriate advices on johkasou O&M

Publication of monthly journal JOHKASO and books related johkasou technology/ administration
Holding a national conference on johkasou technology, johkasou technicians and other stake-holders coming
togetherfor exchanging information and discussing issues on johkasou businesses.

•

Seminar courses for CPD of johkasou techniciansSpecial seminar for johkasou desludging workers
Special seminar on installation management of johkasou
Special seminar on O&M of compact type johkasou
Special seminar on desludging practice of compact type johkasou

435. Japan’s experience on decentralized
domestic wastewater treatment
Johkasou product(Hardware)Management
Sys. (Software)・structural standards
・product certification
・capacity determinationof johkasou for buildings
・R&D of johkasou tech.
・manufacture tech.

 Strengthen regulations on the industry
 Provide high quality, low price product Provide good O&M/desludging service

 Establish national subsidy program Training/certification system forjohkasou technicians・ law, regulation, policy
・ O&M, desludging sys.
・ training, certification
・Dev. of O&M tech.

Promotion・national administration(Johkasou office,Johkasou Act)・domestic wastewater
treatment plan・national subsidy program・monitoring system
・public awareness44 The Japan Sanitation Consortium (JSC) was launched on 16 October 2009
 JSC consists of the 5 expert organizations that contribute to the management ofwastewater and sludge in Japan (on-site and off-site sanitation)
 JSC aims to utilize Japan’s expertise in sanitation as well as success stories andexperiences from other countries to offer a wide range of solutions and strategies for
sanitation improvement in the Asia-Pacific region

 JSC collaborates with ADB, JICA
international organizations, NGOs, etc.
for sanitation improvement

 JSC MEMBER ORGANIZATIONS
Off-site Sanitation- Sewerage Business Management Centre- Japan Sewage Works Association- Japan Sewage Works Agency
On-site Sanitation- Japan Environmental Sanitation Center- Japan Education Center ofEnvironmental Sanitation

Japan Sanitation Consortium (JSC)
Regional Water Knowledge Hub for Sanitation
JSC Expertise Member of a regional network of water experts, committed for sanitation improvementin the Asia-Pacific region
 On-site and off-site sanitation professional organizations

JSC Services
 Networking, information gathering & knowledge sharing, support tointernational donor organizations, NGOs
JSC Partners
 ADB, JICA, Japan Water Forum, UNICEF, etc.

Thank you for your attention
e-mail: pierre@jsanic.org
www.jsanic.org