Sewer System in Japan

Dr. ICHIKAWA, Arata

Professor

Graduate School of Recycling and Environmental engineering

Fukuoka University

Self Introduction

1937, burn in Tokyo1961 Graduate from Civil Eng., The university of Tokyo1963 Master Degree form The University of Tokyo

(Civil Engineering)

1964 Assistant, Dept. of Urban Eng., UT1965 Lecturer, Dept. of Urban Eng., UT1968 Associate Professor, Dept. of Urban Eng., UT1997 Retire from UT, by the time limitation Professor of Environmental Eng., Kyoto University2000 Retire from KT, by the time limitation2001 Professor of Fukuoka University

Self Introduction (2: Majoring study field)Integrated Water Resources and Quality Planning

Field: The Tama River in Tokyo The Lake Biwa, in Kyoto

Methodology: HydroInformaticsGathering information and their integrated analysisCharacteristics on watershed: cross sections, slope of a riverWater budget: runoff data, water usage, effluent Water quality, mainly organic matters, eutriphicationHuman activities: population, industrial activities, housing, i

ncluding historical viewsWater Technologies: Purification, sewerage treatment, etcIntegration

Now, this methodology is the most popular, after the progress of computer science.

Seminar for the integrated understandings on recycling and environmental engineering

Students of our department come from various fields, not only civil engineer, chemical engineer, mechanical engineer, but another faculties; such as economics, science and agriculture.

As the introductory education, we organize the seminar for the integrated understandings for 100 day.To visit about 15 fields. Recycling and water facilities.

Preparatory lectures, preparatory survey by students, study tour, completion of a report, presentation, comments from faculty members and final reports after each study tour, every week.

This visit is one of these activities

4 years research activitiesConstruction waste management:

2002-04 by 2 master students tackled with this topics

2003-present: Mr.Matsuda, succeeded their research and developed it to the total system.

Joukasou, private treatment facility of sanitary sewarage2003-present: denitrification system

Transportation of hazardous wastes of PCB2003-05: by working student at the transportation company

Recycling of shredder dust:2002-04: awarded a poster prize from Japan Society of wastes

4 years research activities (2)

Rainfall-runoff model:2002-present: Mr.Yamashita’s theme for forest regi

on

2004-present: Mr.Tateishi, for urban area

Local currency:2002-present: by the alumina of Faculty of Economi

cs

Sewer System in JapanThe oldest Sewer system is Taikou Sewer, built in 16 th cen

tury, in Osaka, a part of which is still active.Modern SS are in Yokohama (residential Area for foreigne

rs) and in Tokyo (the most active area) in the middle of 19th century.Those are the combined sewer System

Treatment facilities: Mikawashima, Tokyo, in 1922Followed by Osaka, Nagoya.In Local Cities there were no SS, except Gifu and Toyohashi

The basic principle: How to enlarge the served population Combined Sewer System has been introduced.

At the age of the rapid economic growth, the public water courses were much polluted, then the Government changed his mind to Separate Sewer System.

Sewer System in Japan (2)

Pollution Control at the rapid economic growthEffluent standard, to keep the environmental standard

The construction of Sewer System, less than 10% of served population to 67% in 2004. But it takes a long time and huge money.

After that, the construction of SS is one of the main political issues in Japan 1.5% increment of the population per year

Now about \3 bil per year in 2004

Main target is pollution control, it means rain water is out of the target.

Night soil treatment

In Japan, night soil is determined as one of the solid wastes, which managed by the Min. of Public welfares,

At the first stage, conduits were managed by Min. of Construction, Treatment facilities by Min. of PW.

The government decided to unify the management of SS by Min. of Construction. But Joukasou, private night soil treatment facilities are still controlled by MPW.At the beginning of 1990’s about 450 thousand units were sold.

Now, the diffusion of in the middle and small cities is the keen issue, by zoning of sewer system.

Our prides on the Technologies in Sewer system

The proposal of the equivalent roughness in a small catchment, by Dr. T.Sueishi, the pioneer of the distributed Model, in 1957.

Reaeration coefficient, numerically solved by the energy consumption in the flowing water, by Dr.T.Murakami, 1967.

De-nitrification Process for the Night soil treatment facility, by Dr. Y.Matuo and Ebara Infilco GroupFirst facility was built in Matsue, front of the lake Nakanoumi,

1968. And now this concept has been applied to many sewerage treatment facilities with high and costless modifications

Our prides on the Technologies in Sewer system (2)

Runoff reduction Sewer System, developed by Dr. S.Fujita and Tokyo Met. Gov., at the beginning of 80’sSeparation of rain water at the inlet of Sewer System in the co

mbined sewer system. The main concept is the storage and slow discharge, controversy of the old concept of SS.

Jacking method: for the construction of conduit system, without excavating the surface, developed by the construction firms from 1960’s.Now, it develops to the less than 500mm pipes and more than 2

50m length with leading robot. Especially high technology at the high ground water table area.

High performance of the effluent from treatment facility.About 5-7 BODmg/l, 1-2 ATU-BODmg/l

Estimation of Runoff from a rain

This topic is the main problem for a long times.Lloyd Davis summarized it into the Rational formula.

Qmax=c x I x A/360, c: runoff coeff. I: rainfall intensity(mm/hr)A: area(ha) Q: runoff(cubm/s)Easy to handle, less parameters. So it has been used for more tha

n 100 years for all over the world.

Especially, in the field of Sewer design (determination of diameter of conduits) Rational formula has been applied.This is one of the lumped Model.

In 1962 Road Research lab, UK, developed a new method TRRL method: divided the watershed into the contour line of eq

ual concentration time. This is the beginning of the distributed model with computer technology.

Watershed

Lumped Model

Down stream

Upstream

流下方向

断面

N

o.1

Only determine the peak flow and/or hydrograph at the end of the watershed

集中型モデル下流

上流

本流の河川

流　域

Watershed is expressed by the typical parametes and representative rainfall in the whole basin

Output is the peak flow and/or the hydrograph.

①convenient with less parameters

②no other model had been developed

③simple calculation and easily understandable

Other lumped models are tank model, reservoir function model

Howerer, now-a-day, more detailed information were required by the stakeholders

Distributed Model

United States: for the water quality management

Europe: for the rehabilitation of Sewer systemWhere, how and the scale, to be improved.

In 1978, volunteers on this problem gathered to exchange information on it, which developed to USD.This month 10th Conference will be held in Denmark.

In 1981, on the 2nd Conf. new models were introduced:SWWM(USEPA), Wallingford Procedure (now InfoWorks),

ILLUDASA (Illinois Univ.)

Design concept, mathematic model, idea, computational techniques, scales, targets speed for computation and so on.

My contributions

Fortunately, I attended this meeting and got a good relationships between model giants:Prof. Ven Yehn, Dr. R.Price, Prof. W.Huber (Florida Univ.)

I had been a vice chairperson on the Joint Committee on Urban Storm DrainageJoint committee: IAHR (quantity), IWPRC (Quality)

So I introduced these concepts into Japan.In the field of sewer eng., many cities adapted these models,

The biggest applied area is for Tokyo Metro. With more than 105km2.

And more than 300 applications are reported.

Distributed Model

Lower stream

Up stream

流下方向

Sub Catchment

集水域

集水域

集水域

集水域

断面

N

o.1

本流の河川

断面

N

o.2

断面

N

o.3

断面

N

o.4

断面

N

o.5

集水域

Main river channel and sub catchments, inflowed from tributaries.

We could get hydrograph at any points on the main channel.

下流

上流

河 道 モ デル

小流域

小流域

小流域

小流域

小流域

小流域

分布型モデル

Main river Dynamic wave model

Subcatchment Lumped Model

Determined Hydrographs for each sub catchment by a lumped model, and calculates the water movement by a mathematical model.

①hydrological conditions could be changed for each sub catchment.

②hyetograph should be prepared for each sub catchment.

③High speed calculation on Dynamic Wave model is applied for these models.

Sewer model

The complicated structures of sewer system, joints, changes of slope, diameter, were assumed to be impossible to solve mathematically.But recent computer technology could solve these problems.

Now 100 thousand nodes (manholes) could be treated.

Hydraulic in Sewer Pipes is also complicated:Open channel flow in the usual time and pressured flow in rainy

conditions.

This phenomena are solved by the introduction of Preissman Slot.

Computational technology: differential equation, an itteration methods are introduced.

MOUSE (Denmark), XP-SWWM (USA), InfoWorks (UK)

Preissman Slot

Japanese Improvements on these ModelFlood (Inundation) control:

Design of networks, enforcement of the sewer system, real time control, risk management by announcement of the occurrence of inundation to habitants.

Improvement of Combined sewer systemThe reduction of CSO (Combined Sewer Outflow): volumes,

loadings, the number of times.

Improvement of model by Japanese engineers:Practical uses of Sewer Asset inventories

Application of GIS to inundation forecasting

Surface flow on the roads, double pipe lines

Gathering the checking data for the identification of parameters.

Future problems to be solved

Integration of analysis on sewer and river system.Sewer system: as a sub catchment, river is main channel.

There are many differences between both sites:Design criteria: no flooding for river engineering

Design rainfall: 50mm/hr for sewer system, 200years of RP

Runoff coefficients for a rational formula

Pursuit of surface runoff: after inundation.For a hazard map to the habitants.

Real time control:Pumping system, detention tanks,

Observation data for the identification of parameters.

Purification works

Sewerage treatment facility

Closed zone

forest

Paddy field

Urban area

Wetland

用水路

Mr. Yamashita is challenging for these problems, Appling this model for the forest zone.

Estuary

Thank you for your attention.

断面をたくさん並べて、それをつなげることで、パソコン上に河道を立体的に再現する。必要な情報は流入ハイドログラフと河道情報

パソコン用市販ソフト InfoWorks RS を使用

河道モデル