The 10th International Workshop on Decentralized Domestic Wastewater Treatment in Asia

4th November, 2022

KeynotePollutant load of gray water and theimportance of its treatment

Dr. Hiroshi Yamazaki
Professor, Department of Civil and Environmental Engineering, Facultyof Science and Engineering, Toyo University

Changes in domestic wastewater treatment (primary stage)
JapanWorld （Asia）

primary stage
Night soil removal
secondary stage（early period）
Treat hygienically「 hauler of manure 」

secondary stage（late period）
Conserving the water
environment「 A night in London where
the scum falls on thedrunkard's head 」（ by Hogarth, 1738 ）

tertiary stage
Circulate water/waste
protect the environment「 Edo Meisho Zue 」（ Collection of the National DietLibrary)2Changes in domestic wastewater treatment (secondary stage at early period)
JapanWorld （Asia）

primary stage
Night soil removal
secondary stage（early period）
Treat hygienicallysecondary stage（late period）
Conserving the water
environment

Old type
JohkasouUntreated
domesticwastewater

Septic tanktertiary stage
Circulate water/waste
protect the environment

Untreated domestic wastewater3

Changes in domestic wastewater treatment (secondary stage at late period)
JapanWorld （Asia）

Sewerage coverage ratio：81%

Sewerage coverage
ratio：2-3%

primary stage
Night soil removal
secondary stage（early period）
Treat hygienicallysecondary stage（late period）
Conserving the water
environment

tertiary stage（Indonesia）

Johkasou coverage ratio：9%

Circulate water/waste
protect the environment
Johkasou4

Situation of domestic wastewater treatment in Asian countries
Penetration rate of domestic wastewater treatment by centralized treatment(sewerage) in Asian countries

Centralizedtreatment(sewerage)

Discharge of night soil and domestic wastewater into the water environment
in Asian countries
countryfeces (tons)

Cambodia

85,000Indonesia

urine (m3)Gray water (m3)

BOD (tons)

852,000

3 million

181,500

6,406,000

64,059,000

8,541 million

2,137,000

Philippines

4,237,000

33,900,000

1,962 million

762,000

Vietnam2,275,000

22,754,000

610 million

357,500

Source： WEPA, Economic impacts of sanitation in southeast Asia (2008) The World Bank

5

Wastewater treatment population coverage ratio byurban population size in Japan
Untreated?

Rural sewerageCentralizedtreatment

Wastewater treatment population
coverage ratio: 92.6 % （FY 2021）

JohkasouSource: Ministry of the Environment Johkasou website (http://www.env.go.jp/recycle/jokaso/data/population/),partially modified by the author

6Sewerage and Johkasou development in Japan
Population
densitysmallJoukaou（around 3.9 million units）

large

Seweragetreatment plant（2,146 facilities）

Sewerage pipeline
Rural sewerage

Untreated 7.4%
JohkasouToyo University
Kawagoe campus

9.4%

JohkasouSewerage
80.6%
Source: Ministry of the Environment,
Wastewater treatment population coverage
ratio by treatment facility (FY 2021,nationwide)

Source: Kawagoe City, Basic planfor domestic wastewater
treatment (2019, Kawagoe City)

Sewerage7

Factors polluting rivers (BOD load ratio by emission source)
Others 5.9%
Livestock 5.5%

livestock

wastewaterfrom livestock

Industry
17.3%
Treatedwastewater
22.7%

industry

wastewaterfrom industry

Domesticwastewater
includingnight soil
civil life

Untreated
Graywater
48.6%

Pollution load ratio in rivers(BOD load ratio by emission source)
Source: Saitama Prefecture Environmental
White Paper 2013

Treatedwastewater

Untreated Graywater（around 10 %）About 50% ofpollution
causes8

Pollution load of each wastewater to the water environment
BOD（g/PE・day）

Coliform（cfu/PE・day）

T-N（g/PE・day）

LAS（g/PE・day）

Old type Johkasou
Untreated Graywater

Old type Johkasou

JohkasouGraywater

JohkasouA large amount of pollutant load
remains in the treated water fromOld type Johkasou and Graywater

Source: Ministry of the Environment Johkasou site:
https://www.env.go.jp/recycle/jokaso/publicity/pamph/pdf/pp_for_the_clean.pdf

9Effects of each wastewater on aquatic organisms
Effect of each effluent on algae growth (AGI)
Growth inhibition rate (%) at 80%
concentration【effluent from Johkasou】【effluent from Old type Johkasou】【Graywater】

1209060

growthinhibition
10%30
100-30Inhibited(80% concentration zone)

Average growth inhibition rate
(80% concentration zone)

Johkasou

20/57

7.5%

Old type
Johkasou

40/43

46.9%

Graywater

33/45

33.0%

Effluent from Old type
Johkasou or Graywater
inhibit the growth ofaquatic organisms (algae)
10Effects of each wastewater on aquatic organisms
Factors Affecting Algae Growth in Each Wastewater (TIE)
2.0ba,ba

1.0aa,ba0.5

2.5
2.0

①②③④

⑥a,b1.0aa②③0.5①sample

aa

④a,b⑤

⑥a,b

Graywater-1

1.5
1.0
0.5
0.0

①aa,b②③a,b④a,b⑤

2.0⑦

a: Significantly
decreasedcompared tocontrol (p<0.05)

Graywater-2

1.5
1.0
a0.5
0.0

①②a,ba,b④⑤a,b③① control② withoutpretreatment③ EDTA
④ thio⑤ SPE⑥ aeration
⑦ pH

⑥-0.5

⑦

Old type Johkasou1.50.0⑤

growth rate (/day)

1.50.0growth rate (/day)

Johkasougrowth rate (/day)

growth rate (/day)

2.0a,b⑥

b: Significant
increasecompared tounpretreatedgroup (p<0.05)

Group of Suspected Toxic Substances

JohkasouCationic metals, oxidizing agents(disinfectants)

Old type Johkasou

Organic matter, NH4-N, others

Graywater

Organic matter

Graywater

Oxidizing agent, organic matter

Factors Affecting Algae Growth Organic matter remaining in Graywater Organic matter and NH4-N remaining ineffluent of Old type Johkasou

11GHGs remaining in each wastewater

Average D-CH₄(mg-CH₄/L)

GHGs remaining in each wastewater

Untreated Graywater

JohkasouAverage D-N₂O-N(mg-N₂O-N/L)

Old type Johkasou

0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
0.04
0.03
0.03
0.02
0.02
0.01
0.01
0.00

【BOD vs CH4】
Old type
JohkasouGraywater

Johkasou0204060
Average BOD(mg/L)

80【T-N vs N2O】
Old typeJohkasou

Graywater

Johkasou020406080
Average T-N(mg/L)

100

Effluent of Old type Johkasou and Graywater contain residual GHGs
Source: Environmental Research and Development Fund, Elucidation of GHG emission mechanism derived from wastewater
discharged into the environment and study of emission amount calculation method

12Conversion from Old type Johkasou to Johkasou
Prohibition of new installation of Old type Johkasou
Johkasou Act revision （FY 2000）

Old type Johkasou （3.6 million units）
Untreated Graywater （7.4%）

Conversion from Old type Johkasou to Johkasou• Mid-term (about 10 years) Generalwastewater treatment• Long-term (20-30 years) Building asustainable sewage treatment system
Source: Prefectural Concept Formulation Manual (2014)

Johkasou （3.9 million units）

Conversion from Old type Johkasou to Johkasou is underway in Japan13

Conversion from Old type Johkasou to Johkasou
Changes in the number of installed units

Old type Johkasou

JohkasouAfter the Old type Johkasous were installed, those were converted to the Johkasou.
（ Double Investment ）Source: Ministry of the Environment Johkasou site, https://www.env.go.jp/content/900518582.pdf

14

Designation status of river water quality types in Saitama Prefecture(FY1990)

Usage Guidecolor

rate of statusannual Ave. of BOD

Very good
good
moderatelittle polluted
polluted
very polluted

1.0 mg/L or less
2.0 mg/L or less
3.0 mg/L or less
5.0 mg/L or less
10 mg/L or less
10 mg/L or more

Source: Type designation status in Saitama Prefecture

Water quality in the lower reachesof the river (southeast region):very polluted
15

Designation status of river water quality types in Saitama Prefecture(FY2020)

Usage Guidecolor

rate of statusannual Ave. of BOD

Very good
good
moderate
little polluted
polluted
very polluted

1.0 mg/L or less
2.0 mg/L or less
3.0 mg/L or less
5.0 mg/L or less
10 mg/L or less
10 mg/L or more

Source: Type designation status in Saitama Prefecture

Water quality in the lower reachesof the river (southeast region):
little polluted
16

Activities of the world (United Nations)
Millennium Development Goals (MDGs)

A little more!

・ With 1990 as the base year and 2015 is thedeadline for achievement
Target 7.C
Halve the proportion of people without
sustainable access to safe drinking water andsanitation.

• 2.1 billion people have access to improved sanitation• 2.4 billion people still use unimproved sanitation facilities• 946 million people still practice open defecation

17Activities of the world (United Nations)Sustainable Development Goals (SDGs)

・ With 2015 as the base year, 2030 is the deadline for achievement
Target 6.2:
By 2030, achieve access to adequate and equitable sanitation and hygiene for all and end
open defecation, paying special attention to the needs of women and girls and those invulnerable situations
Target 6.3
By 2030, improve water quality by reducing pollution, eliminating dumping and minimizing
release of hazardous chemicals and materials, halving the proportion of untreatedwastewater and substantially increasing recycling and safe reuse globally18

From hygiene improvement to environmental improvement
MillenniumDevelopment
Goals (MDGs)

secondary stage（early period）
to treat hygienically

Old type Johkasou
Untreated Graywater

Sustainable
Development
Goals (SDGs)

secondary stage（late period）
to conserve thewater environment

JohkasouMillennium Development Goals → Sustainable Development Goals
Sanitary treatment → Water environment conservation19

Major pollutants and technical countermeasures related to thewater environment
Target substanceshift

Primary stage to
Secondary stage at early period（sanitation issue）

Secondary stage at late period（water environmental issue）

tertiary stage（environmental issue）

Pathogensituationcholeraorganic matter(BOD)

River pollution/sludge

heavy metal

Pollution
problemNitrogenPhosphorus

eutrophication

Water / waste

depletion of resources

greenhouse gas

Global warming

Asiancountries

Effects onaquaticorganisms
Japan

Asian countries need to develop wastewater treatment infrastructure
in a leap
20Changes in domestic wastewater treatment（tertiary stage）
primary stage
Night soil removal
secondary stage（early period）
Treat hygienically

Coverage
ratio
普及率

100%
80%
60%
40%
20%

Water：97.9%
水道普及率Johkasou Act Wastewater：92.6%
汚水処理普及率

Sewerage low0%1950 1960 1970 1980 1990 2000 2010 2020年

secondary stage
Changes in water infrastructure penetration rattio in Japan（late period）
secondary stage （late period）
Conserving the watersecondary stage
environment
BOD removal → Advanced（early period）
treatment, Compact/Energy saving

tertiary stage

Circulate water/waste
protect the environment
Primarystage
generation

sanitation→environment

Old type Johkasou（Black water only）

Johkasou（both Black waterand Graywater）

tertiary stage• Water/waste
circulation• Measures against
global warming

21Building an environment-friendly Johkasou system
Reduction ofwater intake

Reduced water consumption
Energy saving
water saving
equipment

Water treatment plant

Sludgetreatment
Influent(energydiversificationcreation)
Energy saving

QoL
Living area
Disposer

GHGs emission
reduction

JohkasouEffective use ofwater resources

Advancedtreatmentwater pollution
load reduction
Regional
circulation

Water
resources

River, lake, pond
Measures against
eutrophication
ecosystem

Prevention of water pollution ・Ensuring public health ・Maintaining biodiversity
Recycling of water/waste, environmental conservation,
prevention of global warming
Building an environment-friendly Johkasou system22

At the end ・・・

Thank you very much for your attention.
From now on, we would like to work together with you toresearch and act toward the construction of an environmentfriendly Johkasou system.
We look forward to your continuous support and cooperation.

Dr. Hiroshi Yamazaki
Professor, Department of Civil and Environmental Engineering,
Faculty of Science and Engineering, Toyo University