January 24, 2019

Concept, Methodology and Implementationof TMDL/TPLCS in Japan---The 40 Years History and Current Issues---

Mitsumasa OKADA, Ph.D.
Executive Vice-President, The Open University of Japan
Questions and comments to okada.mitsumasa@ouj.ac.jp
1

CONTENTS OF LECTURE Targets of water quality:
Environmental water quality standards (EWQS)
What is clean water and for what?

 Effluent regulation:
How to clean-up water efficiently and equally?

 Effluent quality standards
 TMDL (Total maximum daily loads) for COD, N, P

2

Water pollution by industrial wastewaters
Dokai Bay, Kita-Kyushu, Japanca. 1990s: Restored

Dead Seaca. 1960s: Polluted33How to manage polluted waters
Human activity （wastewater discharge）
No use : polluted
Water use : problems
Human healthLiving environment : odor,

Polluted water

fishery, drinking water,…

Clean up： avoid problems
Parameter, level?

 Purpose of purification?
 Environmental water quality standards！
4

Environmental Water Quality Standards (EWQS) :The Basic Law for Environment Administrative targets and criteria for promotion ofcomprehensive measures against water pollution
 Standard conditions to be achieved and maintained inpublic water bodies
 To protect human health To prevent health damages like Minamata and Itai-Itai diseases

 To conserve living environment
 To protect all the water uses closely related with daily human life
 To protect the living environment for plants/animals closely
related to human life

5

EWQS for Rivers
category

water useAA

Water supply class 1 ; conservation ofnatural environment, and uses listedin A-E
Water supply class 2 ; fishery, class l;bathing and uses listed in B-E
Water supply class 3 ; fishery, class 2,
and uses listed in C -E
Fishery class 3 ; industrial water, classl, and uses listed in D -E
Industrial water class 2 ; agricultural
water; and uses listed in E
Industrial water class 3 ; conservationof living e nvironment

A
B
C
D
E

pH

standards
BOD
SS

DO

CG

6.5-8.5

1

25

7.5

50

6.5-8.5

2

25

7.5

1,000

6.5-8.5

3

25

5

5,000

6.5-8.5

5

50

5

-

6.0- 8.5

8

100

2

-

6.0-8.5

10

*

2

-

*no floating matters like garbage

6Notes : Water Quality Standards forRivers (1) The standards are based on the daily average values
 Conservation of natural environment : Conservation ofnature and natural resources.
 Water supply: class 1 – can be treated by simple purification process such as
filtration.
 class 2 – can be treated by conventional purification processes
such as sedimentation and filtration.
 class 3 – can be treated by advanced water purification
processes with pretreatment.

7Notes : Water Quality Standards
for Rivers (2) Fishery: class 1 - For fishes such as trout and bull trout inhabiting
oligosaprobic water, and those of fishery class 2 and class 3.
 class 2 - For fishes such as the salmon family and Ayu (sweet fish)
inhabiting oligosaprobic water and those of fishery class 3.
 class 3 - For fishes such as carp and crucian carp inhabiting βmesosaprobic water.

 Industrial water: class 1 – to be treated by conventional processes such as
sedimentation.
 class 2 – to be treated by advanced purification processes withchemicals.
 class 3 - to be treated by special purification processes.

 Conservation of living environment: no unpleasant odor at riverside.
8

EWQS for Lakes and Reservoirs: COD(volume > 10 million m3)
category

water use

pH

COD

SS

DO

CG*

AA

water supply class 1, fisheryclass 1, conservation of naturalenvironment, and uses A-C

6.5-8.5

1

1

7.5

50

A

water supply class 2 and 3,
fishery class 2, bathing, anduses B-C

6.5-8.5

3

5

7.5

1,000

B

fishery class 3, industrial waterclass 1, irrigation water, anduse C

6.5-8.5

5

15

5.0

-

C

industrial water class 2,
conservation of environment

6.0-8.5

8

**

2.0

-

*number of coliform groups (MPN/100 ml), **no floating matters
9

EWQS on Nitrogen and Phosphorus
for Lakes and Reservoirs
Category

water use

T-N

T-P

I

Conservation of natural environment, anduses listed in II-V

0.1

0.005

II

Water supply classes 1, 2, 3 ((except for
special types), fishery class 1, bathing;
and uses listed in III-V

0.2

0.01

III

Water supply class 3 (special types), anduses listed in IV-V

0.4

0.03

IV

Fishery class 2, and uses listed in V

0.6

0.05

V

Fishery class 3, industrial water;
agricultural water; conservation of living
environment

1.0

0.1

10

Wastewater treatment to satisfy with EWQS?
Complete removal of pollutants from all the wastewaters?
 (Technically) feasible by advanced treatment, i.e. ozone, UV,
activated carbon, …..
 Too much to satisfy with EWQS?
 Waste of energy, chemicals, materials and funds may result inother problems, i.e. climate change, waste disposal,
bankruptcy, move plants to other region/country……

Appropriate/ necessary removal from wastewater!
Efficient : satisfy with EWQS
Fair

: equivalent efforts among polluters

Feasible : the best available technology(professional judgement)
11

WASTEWATER TREATMENT TECHNOLOGYGAS： CO2, CH4, N2O, NH3
WASTEWATER
pollutants

DECOMPOSITIONSEPARATION

Energy, chemicals, materials(O3, activated carbon, resin, membrane,…)Recycle/reuse:energy, material

LIQUID：
Inactive/harmlesssolids, solutes

SOLID：
excess sludge, waste materials (spentcarbon, resin, membrane, …)
12

Effluent regulation for water uses

Human society
technology

Local

Environment
EWQS

provisional
National
minimum

TMDL

13

NATIONAL UNIFORM EFFLUENT QUALITY STANDARDS Uniform and national minimum criteria for effluent quality
 Regulate effluent discharges into public water bodies
from the specified facilities (ca. 600 industrial categories).
 Parameters to be controlled Human health: all facilities

 Living environment : daily discharge > 50 m3

Small exemption = Fair
 Effective: Little environmental impacts
 Feasible: small budget, lack of human resources
14

NATIONAL UNIFORM EFFLUENT QUALITY STANDARDSParameters on living environment
parameters

standard values (mg l-1 or less)pH
5.8-8.6
BOD, CODMn
160 (daily average = 120)SS
200 (daily average = 150)
n-hexane extract
5.0 (mineral oil), 30 (animal fat and vegetable oil)phenols
5.0
copper3.0
zinc
5.0
dissolved
Fair: Industrial
Fe, Mn wastewaters
10.0, 10.0 must be treated to the equivalentchromium
quality with the2.0
conventional domestic wastewater
fluorine
15
number
Small ofexemption:
C.G.
3,000 (ml-1 daily average)
120 discharge(daily average= 60)
 Facilities with daily> 50
m3
nitrogen
16 (daily average= 8)
phosphorus
 Effective: Little environmental
impacts
 Feasible: small budget, lack of human resources15

Local Rigorous Effluent Quality Standards
Local (prefecture) ordinance for local
requirements
if the national uniform effluent quality
standards are not enough to satisfy with the
EWQS for a specific local water bodyAll the local governments have put
standards in force

16

Local Rigorous Effluent Quality Standards
by Prefectural Governments : CODMn
prefecture

water areanew

operating

Kanagawa

A: protected lakes

5 (3)

20 (15)

A: other lakes

15(10)

25 (20)B

25 (20)60 (50)marine25 (20)60 (50)15-12020-120Shiga
Hiroshima

first category

50 (40)second category

85 (65)third category

120 (90)

forth category

130 (100)

Kure area

15 (10)-40 (30)

15 (10)-125 (85)

Seto Inland Sea

15 (10)-50 (40)

15 (10)-130 (100)Different standards among: Prefecture, water area to satisfy with160
EWQS
National minimum(120)
daily maximum(dailyandaverage)
mg l-1 or less
 New
operatingfacilities- ranges dependent on discharge volume and industries

 Discharge volume and industrial categories

17

Local Rigorous Effluent Quality Standards
by Shiga Prefectural Government : T-N, T-P
operatingnew
Daily volume ofdischarge (m3)
T-N
T-P
T-N
T-P
10 - 3040
830
230 - 5025
4
20
2
food (except for box
lunch production)
50 - 1,000
20
3
12
1.5
1,000 152
10
1
10 - 3040
630
230 - 50152
12
1.2
textile50 - 1,000
12
1.5
8
0.8
1,000 101
8
0.5
10 - 3040
2
20
2
30 - 5015
1.5
12
1Other production
Different
50 - 1,000standards
12 among:
1.2
8
0.6
8
0.8
8
0.5
1,000Industrial
categories
night soil treatment
10 20
2
10
1
jokaso
5
20
5
 10
Daily
volume20of discharge
10 - 3,000
20
20
0.5
１
sewage treatment plant3,000New
facilities- and operating
20
15
0.5
１
NATIONAL UNIFORM STANDARDS
120(60)16(8)120(60)16(8)18 l-1)(mg
industry

Provisional effluent quality standards
 Some industries are difficult to comply with the national uniform
effluent quality standard irrespective of the best available
technology
 Exemptions for the national uniform standards
National uniform: N(120, 60), P(16, 8)(daily maximum, average), mg l-1

pig/cattle farm:

N (700,350), P (100,50)

coke oven:

N (170,130)

dairy products:

P (30,15)

 Specified industries: N:55, P:39
 Develop and adopt new technology to satisfy with the national
uniform standards in 5 years (1993-1998)

19

REVISIONS OF PROVISIONAL STANDARDS
Industrial
categories

Provisional 1st revision(1998-2003)
standard

2nd revision 3rd revision 4th revision(2003-2008)(2008-2013)(2013-2018)(1993-1998)

Natural Gas

200 (180)

170 (150)

160 (150)

160 (150)

160 (150)

Feedlot

270 (350)

260 (200)

190 (150)

190 (150)

170 (140)

Silver Oxide

560 (370)

350 (300)

240 (210)-

Cobalt Oxide

1100 (880)900 (750)

550 (300)

Lead Chromate
Paint

1,500
(1,000)1,300 (950)-400 (120)

N

P

Vanadium &Molybdenum
Compounds

26,000(17,000)

8,000(6,000)6,000(5,000)5,000(3850)

4,250(3,500)Feedlot

100 (50)50 (40)30 (24)30 (24)20 (15)

Phosphorus andCompounds

640 (280)

90 (40)40 (10)40 (10)20

PERCENT COMPLIANCE FOR EWQSParameters on living environment
100% complianceestuary（COD)
80
river（BOD)

60
40

lake（COD) Effective
for rivers
20 Questionable for closed waters, i.e. lakes and estuaries

0
1970

1980

1990

2000

2010
21

PERCENT COMPLIANCE FOR EWQS
IN MAJOR ESTUARIES% compliance

100
80
60
40
20
0
1970

1980

Seto Inland Sea

Tokyo BayIse Bay

Osaka Bay

1990

2000

2010

 Little improvement in major estuaries！

22

Why cannot satisfy with the standards
for COD?
 EUTROPHICATION
 Increase in internal loading /phytoplankton production of COD
 Environmental Quality standards for N and P, Effluent
standards for N and P
 INCREASE IN TOTAL LOADING OF COD
 TMDLs: Total Maximum Daily Loads
 NON-POINT SOURCES
 TMDLs

Is the standard appropriate？
 Parameters / values?
COD, BOD→TOC？
23

How to satisfy with the EWQS: Ct ?
Industries

TMDL: Total Maximum Daily Loading
Le = Qe x Ce : effluent loading(Loading)=(flow)x(concentration)othershousehold

Wastewater
treatment plants

Le6
Le7

Le1 = Qe1 x Ce1

Total Loading= Σ Lei

Le5

Ct = Σ Lei/V - R
Wastewater
treatment plants

household

Cｔ

Le2
Le3

Wastewater
treatment plants

Le4

More industries?

24

TOTAL MAXIMUM DAILY LOADS:TMDL
Effluent standards
The best available effluents based on
current wastewater treatment technology
Technology Based Approach

TMDL
The largest capacity of effluents tomaintain water quality
Water Quality Based Approach25

How to control pollution loads?
Equally and Effectively
 Origin?
Country, prefecture, basin, city….
 Activity?
Point sources: sewage, industriral, domestic,...
Non-point sources: agriculture, forest, city,…
 Pollutants?
N, P, COD, …
26

Generated loading sources on COD
Tokyo Bay（2009）

others12.6 %Live stock

Other sewage

Other non-point
4%

1%

8%

No regulation
5%

Domestic
sewageSmall industry <50 m3 4%
Industry
19.6 %

42%

TMDL industry

Domestic
67.8 %

6%

Industrial sewageWhoshouldreduce?
How
much？

4%

Graywater
17%

Gappei Jokaso
6%

Tandoku Jokaso
3%

Domestic
wastewatermust becontrolled！
27

Generated loading sources on COD
Seto Inland Sea
except for Osaka Bay（2009）
Who should
reduce?
How much？

Others 11.6 %Domestic sewage
7%

Live stock

Other
nonpoint

4%

No regulation

Gappei Jokaso
6%

Tandoku Jokaso
3%

7%

8%

Small industry <50 m3
10%

Graywater
23%

Domestic +Industrial
wastewatermust becontrolled！

Domestic
39.2 %TMDL industry
29%
4%

Industry
49.2 %

Industrial sewage

28

Target of loading reduction by TMDL Target of loading reduction considering: Increase in loading by the growth of industrial activities andpopulation
 Technology for wastewater
sewerage systemtreatment

andimprovementin Realistic and possible target of loading in the target year Interim targets
 Monitoring at each source by available and popular devices andprocedure + reporting system

TMDL directly based on EWQS in U.S.
 Target of reduction to satisfy with EWQS for the water !
 How to estimate loading and corresponding water quality? Bymathematical model?
29

TARGETS OF TMDL FOR COD
1,200

COD loads (t/day)

1,000
800
600

Seto Inland Sea

othersindustrial
domestic

Tokyo BayIse Bay

400
200
079 84 89 94 99

79 84 89 94 99

79 84 89 94 99
30

MAJOR POLICIES IN TMDLs (1)Domestic wastewaters
 Improved management of domestic wastewater by thedomestic wastewater control law
 Increase in the percent service by public owned sewer
systems
 Regulations for domestic wastewater treatment plants
by C values
 Introductions of advanced treatment processes andimproved maintenance Environmental education to reduce domestic loading
31

DOMETIC WATERWATER TREATMENTSYSTEMS IN JAPANNight soil

Graywater

Sewer systemtreatment

Gappei Jokaso

treatment

treatment

Tandoku
JokasoGraywaterCollection+treatment

Night soil

Graywater

Discharge to public waters
32

POPULATION SERVED AND COD LOADING IN
TOKYO BAY AND SETO INLAD SEA (2004）
Tandoku Jokaso +Night soil
9%Gappei Jokaso 5 %TOKYO BAY

Sewerage
86%

Population
served byGappei Jokaso

9%Tandoku Jokaso 5%
Gappei Jokaso

Tandoku Jokaso+ Night soil
24 %graywater
29%

Sewerage
67%

7%

SETO
INLAD SEA

Sewerage(domestic)
59%

COD
loading
Sewerage(domestic)

graywater
50%

36%Gappei Jokaso 8%
Tandoku Jokaso 6%
33

Domestic wastewater loading (1)Volume (L)BOD (g)Treated night
soil
KitchenBathLaundry
Others34

Pollutants in kitchen wastes/ garbage (mg/l)
BOD

SS

N

P

rice washing（1st）

12,000

8,500

110

32

juice

77,000…

230

521,400,000

…

1,400

3,000

soup(ramen)

24,000

4,700

1,100

280

powdered soap

880,000…

…

…

detergent compact)

95,000…

…

…

kitchen detergent

880,000…

…

…

soysouce

220,000…

25,000

3,900

mayonnaise

1,290,000

…

4,400

870

dressing

660,000

…

1,500

110

coffee

5,900

…

350

62

290

…

15

3.7

milk

83,000

…

4,900

1,340

beer

89,000

…

340

132

400

190

27

6

waste oilgreen tea

kitchen (average)

35

Kitchen waste management
Do not dump them especially in case yourgraywater is being discharged without any
treatment Cooking leftover Use strainer    garbage
 Remove before washing Do not dump rice washing wastewater, beer, soup, …..

 Waste oil Solidify, and/or absorb to waste paper Recovery to make soap

 Solid waste Composting, burial, incineration in garden
 Solid waste disposal
36

MAJOR POLICIES IN TMDL (2)Industrial wastewater
Reduction of loading equally among industries!
 Regulation of industrial effluents according to
TMDL standards : C values Guidance for small scale and non-controlledindustries, and increases in the number ofindustries to be regulated
37

CONTRIBUTION OF INDUSTRIAL COD
LOADINGS （2004)
3 TMDL estuaries

food 2%synthetic fiber 3%others12%

petroleum 3%

Paper &
pulp

textile 4%
Steel

5%
45%

Jokaso(industrial)
6%
sewerage(industrial)
6%

Organic
chemical
14%

38

Maximum allowable daily loading of
COD: C values
 Specified industries located in TMDL
 a daily discharge >= 50 m3
 except for cooling water : w/o pollution loads

L = C・Q×10 -3
L: maximum allowable loading for COD (kg day-1)
C: C value = COD (+N and P) concentration specified
by the governor (mg l-1)
Q: volume of specified effluent (m3 day-1)

39

PRODUCTION AND LOADINGS FOR 6
MAJOR INDUSTRIES: 1992
food
fiber
pulp & paper
chemicalpetroleum & coalsteel

3 estuaries
Total Production：¥ 57.8 trillion

Total loading : 274 t day-1
40

REDUCTION OF C-VALUES FROM
THE 1ST TO THE 4TH : examples
C(mg/l)1st

4th

Pulp: chemical, semi-chemical

210

100

Chemical feritlizer

120

50

Petrochemical: aliphatic intermediates

200

90

Petrochemical: organic chemicals

200

90

aliphatic intermediates

200

90

Coal tar

350

170

Organic chemicals

200

90

powder200

80

Jokaso: > 501

120

40

Night soil teatment

120

50

Local markets

120

50
41

INDUSTRIAL COD LOADSTO 3 TMDL ESTUARIES: ratio
3.5

food
textileratio to 1996

3

paper/pulp

2.5chemical2

oil/coal
steel

1.5

others1

sewage0.5
1975

small/no-regulation
1980

1985

1990

1995

2000
42

The 5th TMDL with N and P
 PERIOD： 2000 – 2004
 cf. 1st : 1980 – 1984, every 5 years

 ESTUARIES: Tokyo Bay, Ise Bay, Seto Inland
Sea PARAMETERS：COD (from 1980)、
N、P (from 2000)
 AREAS：all the drainage basin to the specified
estuaries (20 prefectures)
43

EFFICIENCY AND % IN USE OF WASTEWATERTREATMENT PROCESSES

COD

COD + P

COD + N
COD
+ P +N-% removal
COD

N

P

% in
use

1) activated sludge (AS)

80

40

40

30

2) coagulation + sedimentation (C)

50

40

70

20

3) AS + C

85

50

80

4) AS + C + sand filter (SF)

95

50

95

5) AS + C + SF+ activated carbon (AC)

97

50

95

6) Enhanced Biological P removal (EBPR)

80

20

80

7) Biological N removal (BNR)

80

60

40

8) BNR + C

92

65

82

9) BNR + C + SF

95

70

90

10) BNR + C + SF + AC

97

70

90

11) BNR + EBPR

95

60

80

targets

methodsothers

20
-

4

26

44

Annual average COD for 30% reduction
in loading: Tokyo Bay

1999

30% reduction
in COD,N,P
45

Annual average T-N for 30% reduction inloading: Tokyo Bay

1999

30% reduction
in COD,N,P
46

Targets of the 8th TMDL for COD

1000

その他系
othersindustrial
産業系
domestic
生活系

Seto Inland Sea

800
600

Tokyo BayIse Bay

400
200

79
84
89
94
99
04
09
14
19

79
84
89
94
99
04
09
14
19

0
79
84
89
94
99
04
09
14
19

COD loadings (t/day)

1200

47

Targets of the 8th TMDL for T-N

800

その他系
others
産業系
industrial
生活系
domestic

Seto Inland Sea

600
400

Tokyo BayIse Bay

200

79
84
89
94
99
04
09
14
19

79
84
89
94
99
04
09
14
19

0
79
84
89
94
99
04
09
14
19

T-N loadings (t/day)

1000

48

Targets of the 8th TMDL for T-P

60

others
その他系
産業系
industrial
domestic
生活系

40

Tokyo Bay

Seto Inland Sea

Ise Bay

20

79
84
89
94
99
04
09
14
19

79
84
89
94
99
04
09
14
19

0
79
84
89
94
99
04
09
14
19

T-N loadings (t/day)

80

49

COD loading (t day-1)

COD loading to Tokyo Bay
250

Gappei Jokaso
Tandoku Jokaso

200Night soil treatment
Sewerage (industrial)
Small scale

graywater

No- regulation
Animal wastes
Surface run-off

150

100

sewerage (domestic)
industrial

50

0
1975

1980

1985

1990

1995

2000

2005

2010

環境省総量削減専門委員会報告(2015)
第８次水質総量削減の在り方について、平成27年12月
50

COD loading to Tokyo Bay: ratio
ratio to 2010 COD loading

10.0

sewage9.0

food
paper/pulp
chemicaloil/coal

8.0
7.0
6.0
5.0

steel

4.0
3.0
2.0
1.0
0.0
1975

1980

1985

1990

1995

2000

2005

2010

環境省総量削減専門委員会報告(2015)
第８次水質総量削減の在り方について、平成27年12月
51

Average COD improvement in Tokyo Bay: ratio
ratio to 2010 average COD

4.5

sewagejokaso(gappei)
food
textileoil/coal
steel
otherschemical

4.0
3.5
3.0

paper/pulp

2.5
2.0
1.5
1.0
0.5
1975

1980

1985

1990

1995

2000

2005

2010

環境省総量削減専門委員会報告(2015)
第８次水質総量削減の在り方について、平成27年12月
52

TMDL in 40 years: effective or not?
TMDL for COD

100

①

②

③

TMDL for COD+NP
④

⑤

⑥

⑦

⑧

% compliance

80
60
40
20
0
1970

1980

Seto Inland Sea

Tokyo BayIse Bay

Osaka Bay

1990

2000

2010

Aug. 1993：effluent standards for N,P Little
improvement!
 What will be
the next?

2020
53

TMDL for 30 years in Tokyo Bay: COD
Average from 1982 to 1984

Average from 2009 to 2012

環境省（2015）第8次水質総量削減の在り方について（総量削減専門委員会報告）

54

TMDL for 30 years in Tokyo Bay:bottom DO in summer
Average from 1982 to 1984

Average from 2009 to 2012

環境省（2015）第8次水質総量削減の在り方について（総量削減専門委員会報告）55

Percent compliance for EWQS on COD and
T-N, T-P in Tokyo and Ise Bay
100
90% compliance

80
70
60
50
40
30
Tokyo Bay

20
10
0
1980

1985

1990

1995

2000

Ise Bay

COD

COD

NP

NP

2005

2010

2015

56

th
Current issues on TMDL 8

 New EWQS?
 TMDL for Clean and productive estuaries?
57

Why cannot satisfy with the standards
on COD?
 EUTROPHICATION
 Increase in internal loading /phytoplankton production of COD
 Environmental Quality standards for N and P, Effluent
standards for N and P
 INCREASE IN TOTAL LOADING OF COD
 TMDLs: Total Maximum Daily Loads
 NON-POINT SOURCES
 TMDLs

Is the standard appropriate？
 Parameter / value
COD, BOD→TOC？
58

Claims on EWQS for CODMn
 Satisfy with the EWQS?
 If the EWQS on COD is satisfied, the water environment issatisfactory?
 The current water quality is too clean to support fisheryproduction? “A clear stream is avoided by fish”

 The current EWQS is not appropriate for the current
issue on water environment?
 It was good to cope with the serious water pollution in mid 20th,
but still appropriate in the current situation?

 CODMn is not a good parameter for organic pollution
 CODCr is common in the world
 TOC is a better parameter for organics
59

EWQS on Bottom Dissolved Oxygen
category

designated use

・ Area to protect and restore habitats for adultspecies sensitive for low DO
Habitat 1・Area to protect and restore habitats for species
sensitive for low DO in reproductive stages
・Area to protect and restore habitats for most adultspecies except for sensitive species for low DO
Habitat 2 ・ Area to protect and restore habitats for most
species in reproductive stages except forsensitive for low DO in reproductive stages
・ Area to protect and restore habitats for adultspecies tolerant for low DO
・Area to protect and restore habitats for species
Habitat 3
tolerant for low DO in reproductive stages
・ Area for the survival of most tolerant benthic
organisms

DO criteria
4.0 mg/L
or more3.0 mg/L
or more2.0 mg/L
or more60

EQWS and Effluent Standards in TMDL
EWQS
BOD

COD

T-N,T-PTransparency

To control
biodegradableorganics tomaintain DO

To control
organics,
Insufficientoxidation

Bottom DO

To control
Eutrophication

To protect
benthicorganisms

To protect submerged
aquatic vegetation,
recreation

COD

T-N,T-P
Bottom DO

Transparency

BOD

Effluent Standards

61

Time for Q & A

Akitsu, Higashi-HIroshima
62