Conference on Watershed Management forControlling Municipal Wastewater in South East Asia

Policies for Watershed Management forControlling Municipal Wastewater in Japan
July 2016
Norihide TamotoSewerage and Wastewater Management Department
Water and Disaster Management Bureau
Ministry of Land, Infrastructure, Transport and Tourism (MLIT)
Ministry of Land, Infrastructure, Transport and Tourism

Contents

1. Background
2. Overall Policy Structure
3. Basin-Wide Upper Level Plan
4. Practices

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Contents

1. Background
2. Overall Policy Structure
3. Basin-Wide Upper Level Plan
4. Practices

3BackgroundDue to the high economy growth, Japan faced severe environmental problems
in the 1960s and 1970s
Tokyo Bay

Pictures of Water Environment in 1970’s in Tokyo
A river in Tokyo

Kanda River in Tokyo

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Photo Credit : Environmental Bureau of the Tokyo Metropolitan Government

Background
After confronting the severe environment pollution, the government revised
the “sewerage law” in 1970 andthe role of sewerage infrastructure to improve the quality of public water
bodies was officially stated in the law
The planning, construction and operation of the large scale sewerage
infrastructure was accelerated after 1970

5Pollution Diet in 1970

Contents

1. Background
2. Overall Policy Structure
3. Basin-Wide Upper Level Plan
4. Practices

6Objectives of Sewerage Law
The purpose of the Sewerage Law is to contribute to the sound development of cities
and improvement of public health and to preservation of water quality in public water
areas, (Article 1. Sewerage Law).

To establish sewerage system, each local authority set Sewerage
construction plan
・Planned area for sewerage construction
・Location of wastewater treatment facility
・Treatment methods
・Discharge location

Addition to the construction plan,
Basin Wide Upper Level Plan in is required to improve public waters
quality,since water quality of public waters are related with multi-factors
other than domestic wastewater

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Overall Policy Structure in Japan
In Japan, Prefecture Governments have to prepare Comprehensive Basin-WidePlanning of Sewerage System to meet the Water Quality Standards
Law
FrameWork

Basic Environment
Law (MOE)

Ministerial Order

Water Quality
Standards（MOE）

Water Pollution
Prevention Law(MOE)

IndividualLaws

Regulate the wastewater fromindustry
Promote Domestic Wastewater
Treatment (on-site)

Plans
Basic Environment
Plan (MOE)
Program for thePromotion of Measures
Against Household
Effluents

Effluent Standards(MOE)

Sewerage Law(MLIT)
Comprehensive Basin-wide Planning of Sewerage Systems
Standards for the installation and operation of thesewerage system
Subsidy for the construction

Comprehensive Basinwide Planning ofSewerage Systems
Comprehensive plan forsewerage system to meet
the water quality standards
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Contents

1. Background
2. Overall Policy Structure
3. Basin-Wide Upper Level Plan
4. Practices

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Determinant Factors of Water Quality
Water quality of public waters are related with multi-factors

MountainforestFields

Rain-fallLive-stockCityHouse-holdFactory

Public Waters
10Basin-wide Water Quality Improvement
To improve public waters quality, a basin-wide approach is required as well as efforts
by each local authority
Prefecture B.
From Pref. B

Sewerage Service Area(= area of each sewerageconstruction plan)

Town C
Sewerage Service Area(= area of each sewerage
construction plan)

ＴWWTP

City D

Prefecture A
City B
WWTP Ｔ

Water Quality Goal
COD ◇◇mg/L
T-N ▲▲mg/L
T-P ■■mg/L○○ River
Water Quality Goal
BOD □□mg/L
Lands
WatersEnvironment Standard
point of Water Quality

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Comprehensive Basin-wide Planning of Sewerage Systems
To reduce the basin wide pollution load, it is necessary to avoid inefficiency and secure
consistency of each measures.
Thus it is necessary to plan most rational and effective solution for the whole water basin.

Comprehensive Basin-wide Planning of Sewerage Systems
A prefecture must set forth a comprehensive basic plan with regard to public water
areas for which Environmental Water Quality Standards are prescribed, to meet andmaintain the Environmental Water Quality Standards in case water pollutions cover
more than 2 of municipalities. (Ref. to Article 2. Sewerage Law)

About Environmental Water Quality StandardsIn April. 1970, based on the basic law for environmental pollution control, thestandard was set so as to protect human health and maintain a living environment
regarding environmental conditions related with water pollutions of public waters＜FYI＞FY 2013 River (BOD)2,558, Lake(COD)187, Sea (COD)590

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Role of Sewerage: Reduction of Loads mainly from Households
Comprehensive basin-wide planning of sewerage systems, plans to reduce pollution loads
from various sources and improve water quality of public waters
Sewerage serves to reduce pollution loads mainly from householdsBefore

After Comprehensive basin-wide planning

Mountainforest

Mountainforest

LivestockFields

Reduction

LivestockFields
Reduction

Reduction
Reduction

House
Reduction

Factory

Subject to load
reduction bysewer

House

Factory

Public Waters

Wastewater
Treatment Facility

Public Waters
Improved quality due toreduction of pollution loads

Do not improve due to pollution
loads from various sources

Wastewater
Treatment Facility

Extended coverage/ Advanced
treatment of sewer

Water Quality × Water Quantity ＝ Pollution Loads（mg/L）
(L)
(mg)

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Upper Level Plan for the Sewerage Construction
Comprehensive basin-wide plan worked as Upper Level Plan for sewerage construction in
the region where environmental water quality standards are set
Sewerage works in a region where comprehensive basin-wide plan is set must correspondswith comprehensive basin-wide plan (Article 2-2, Article 6 item 5, Article 25-13 item 4,Sewerage Law)
Comprehensive Basinwide Plan

Aim to meet and maintainenvironmental water quality
standards in public waters

Check the Consistencyof the Plan
Inefficient if

Sewer Plan
Projects

individual authority
conducts measures

Comprehensive basin-wide plan serves as the basis of
the planning of sewerage system14

Policy Coordination of Comprehensive Basin-wide Plan
In case Comprehensive plan is set on waters which cover more than 2 of Prefectures,
National government(regional development bureau) coordinates a Basic Policy formeeting Environmental Water Quality Standards among Prefectures(Prefectural quotafor loads reduction objectives)
Basic Policy ofComprehensive Plan
（direct plan）(by regional development bureau）

Region-wide coordination onwaters related with multiple
prefectures

Comprehensive plan
（By Prefectures）
Public Sewerage Plan
(By Municipality）

Basin Sewerage Plan
（By Prefecture）Basin-related
Public Sewerage Plan
(By Municipality）

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Contents

1. Background
2. Overall Policy Structure
3. Basin-Wide Upper Level Plan
4. Practices

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Comprehensive Basin-wide Planning of Sewerage Systems in Pref. Shiga
Though sewerage works are operated by municipalities, water quality protections ofriver, lake and sea waters need region-wide cooperation for efficient implementations
For this, Pref. Gov. set a higher level plan over individual sewer plans to achieve water
quality standards of river, lake and sea waters
Overview of Plan

Conceptual scheme

Scope of yearAround 20〜30 years
Water Quality objectives
Achieve/maintainwater quality standards
Objectives of Sewerage facility
Set the necessary plan of facility
improvement Includes other items

DistrictSymbols
記号

Inspection

District
地区区分

調査実施期間Organization

Environment
環境基準点
standard
point

Shiga Prefecture
滋賀県

Nitrogen/Phosphor
窒素りん環境基準点
standard
point

Shiga Prefecture
滋賀県

Other observation
その他の調査地点
point

MLIT
国⼟交通省

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Flow of Planning（Ex. Pollution Analysis of Lake Biwa）
Based on projections of population/industries growth, estimates the projected volumes of discharges andpollutants
Sets a reduction goal of pollutant load and reduction measures, and reflects on sewerage improvement plan.
Basic survey
Natural condition
Current state and prospect of populationand industry
Current state and prospect of volume ofdischarge and pollutant load.
Continental model
Considering flows of evapotranspiration, river water,and groundwater.

Pollution analysis and pollutant
load reduction plan
Pollution analysis using model
Sets goal of reduction volume andreduction measures.

Sewerage construction plan
Sets designed treatment water
quality
Sets measures of sewage
treatment.
Lake model
Considering the vertical and horizontal
proliferation in Lake Biwa.

5 element model of evapotranspiration, groundwater, overland flow, river water,
point source load calculation.

Lake ecology model
Considering the decomposition and production
by ecology

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