water management technologies...fuji electric’s water quality sensor and control technology is...

Whole Number 187

Water Management Technologies

Fuji Electric’s water qualitysensor and control technology

is playing an active part fromthe water source to water taps.

Acute toxicantsmonitor

Coagulationsensor

High-sensitivityturbidity meter

Trihalomethaneanalyzer

Service qualitymonitor

Aiming at reliable supply of safe and nice water, Fuji Electric keepsa sharp watch on water quality from the source to supply taps.Moreover, water quality is controlled by optimum chemical dosingusing coagulation sensors and chlorine injection under fuzzy controltaking various factors,such as a season, a time zone, and theamount of insolation, into consideration. FAINS

Residualchlorine

meter

Free chlorinemeter

(non-reagenttype)

Turbiditymeter

pH meter

Alkalinitymeter

Conductivitymeter

FUJI ELECTRIC EQUIPMENT for Water Analysis and Control Systems

CONTENTS

Cover Photo:The beautiful Earth that

brought up life and gave birth tomankind is now suffering from ill-ness due to the consumption of alarge quantity of resources and en-ergy by mankind.

At this very moment, it is an ur-gent necessity for mankind to con-centrate intelligence on the resto-ration of the beautiful Earth envi-ronment.

Fuji Electric as a comprehensiveelectrical manufacturer with ampleexperiences and technologies in thefield of water treatment has sup-plied various products for water andsewerage systems to protect theglobal environment.

The cover photo shows an imageof solution technology for watertreatment with the material Earthirreplaceable to mankind super-posed upon a background showingwater, the source of life.

Head Office : No.11-2, Osaki 1-chome, Shinagawa-ku, Tokyo 141-0032, Japan

Water Management Technologies

Trends and Future Prospects of Water 106and Sewage Treatment System Technology

Modern Electrical Technology for Water Treatment Plants 110

Instrumentation, Control and Sensor Technology for Waterworks 121

Instrumentation, Control and Sensor Technology 126for Sewage Treatment Plants

Information Processing System for Water and Sewage Treatment 130Plants

Advanced Water Treatment Technology for Waterworks 137and Sewerage Systems

Engineering and Construction Techniques for Waterworks 144and Sewerage Systems

Vol. 45 No. 4 FUJI ELECTRIC REVIEW106

Masakazu UsuiIwao Matsunaga

Trends and Future Prospects of Waterand Sewage Treatment System Technology

1. Introduction

Since developing the first computer control systemfor waterworks and sewage treatment plants in Japan30 years ago, Fuji Electric has done much to developnew technologies and put them to practical use to meetthe diversified, sophisticated needs of the water treat-ment market.

Water and sewerage system technologies havefaced social problems and subsequent regulation, butthese have acted as driving forces for technical devel-opment and have resulted in progress in the technolo-gies.

Fuji Electric has developed many systems thatwere firsts in Japan, for example: water distributioncontrol with demand prediction, development of anumerical formula for the activated sludge process forsewage, practical application of fuzzy control to waterquality control, installation of optical fibers in sewers,and use of multimedia communications.

Environments surrounding the water system havegreatly changed. The development of new waterresources has been difficult and the problem of waterquality has been complicated and diversified. A higherlevel of quality and quantity than before is required forthe water system to fulfill its social responsibility.

As for the sewerage system, with the rising level ofservicing, such as sewage being regarded as an impor-tant component factor in the circulation of water, andwith social changes, the role to be played by thesewerage system has become more diversified andsophisticated.

The trends and future prospects of water andsewerage system technology are described below.

2. Trends and Future Prospects of Water andSewerage System Technology

In water and sewerage systems, facilities scatteredover a wide area are connected by water channels andconduits. These facilities influence each other whileimplementing an overall function.

Therefore, the proper control of water quantity,quality, and pressure is important. In water systems,

there occur changes in source water quality and inservice water demand. In sewerage systems, changesin treatment quantity and drainage quality due torainwater inflow and abnormalities (water shortages,typhoons, conduit damages, and equipment failures)may occur. It is the responsibility of these systems toattain and maintain high-level service while copingwith these various changing conditions.

To attain this purpose, a system that can gatherthe necessary information for management and controlfacilities in a centralized manner is indispensable.

Water and sewerage system technology must satis-fy these requirements and can fulfill its functions byintegrating component technologies for electric, instru-mentation, computer, and mechanical systems.

2.1 Open monitor and control systemsThe rapid spread of personal computers has made

data processing technology popular, and created de-mand for end user computing such that users couldfreely collect data from monitor and control systems,store that data in their personal computer and utilizethat data in various formats.

However, this demand was contradictory becauseit required that manufacturers guarantee monitor andcontrol systems even if those systems were modified byusers.

Open systems were created in response to thiscontradictory demand. Fuji Electric developed theFAINS-AX series of new open distributed monitor andcontrol systems and the LOGACE series of openmonitoring loggers.

These series combined Fuji Electric’s reliable spe-cial-purpose technology with its widely used general-purpose technology, making it possible to offer systemssuited to user requirements at a reasonable cost.

2.2 Data transmission, control technology and solutionsTo efficiently manage sewerage operations, utili-

ties have recently planned and implemented un-manned pumping plants as well as integrated manage-ment systems for entire sewerage systems usingoptical fiber networks and built in sewer conduits thatconnect sewerage system facilities with each other.

Trends and Future Prospects of Water and Sewage Treatment System Technology 107

Regarding the plans of optical fiber networks forsewerage systems, based on LAN and optical transmis-sion technologies, Fuji Electric will expand the applica-tion range into the remote control of emergencyfacilities and remote maintenance systems to realizepreventive maintenance. Thus, we will offer solutiontechnologies to realize all utility processes from con-struction to maintenance at a minimum cost.

Figure 1 shows Fuji Electric’s solution technologiesfor water environments. Solution technologies are notlimited to the field of communications and control. Forexample, in the case of installation of an onsite powersupply system aiming at global warming preventionand emergency management at an optimized cost, theintroduction of a fuel cell system is a solution technology.

The cost optimization of water and sewerageoperations can not be attained only by reducingconstruction expenditures. The cost is closely relatedto expenses for maintaining facilities and the life of thefacilities. That is to say, consideration of the lifecyclecost is very important, and it is necessary to build asystem with optimum value using the value engineer-ing (VE) method. Solution technology is attractingattention as it is expected to play an important role.

2.3 Technologies against disastersMost suspensions of the water supply due to

earthquakes or other disasters are the result of “point”damages caused by broken water pipe joints, resulting

in “area” damages downstream.Divisional water distribution and a water pressure

regulation system are effective measures against sus-pension of the water supply because “areas” are madesmall and easy to control. These methods have moreeffect when the exchange of water between divisions istaken into consideration. Fuji Electric, with a goodrecord of accomplishment for supplying these systems,has realized stable water pressure regulation and hasimproved the efficiency of water supply by the earlydetection of leakage.

Fuji Electric has introduced to the market manysystems for coping with disasters, for example: porta-ble water supply systems utilizing membrane treat-ments, emergency generators, sensors and communica-tion apparatus with onsite solar cell power supplies,preventive maintenance utilizing artificial intelligenceand statistic processing, apparatus diagnosis equip-ment, and remote maintenance systems using ISDN.As a system vendor, Fuji Electric has tackled manyequipment-related problems, including the earth-quake-proof design of equipment.

3. Contribution to Prevention of Global Warming

It is no exaggeration to say that the prevention ofglobal warming is technically attributable to theproblem of energy. Basically, it is necessary to meetthe increasing demand by improving the demand

Fig.1 Solution technologies for water environment

Reclamation

Sludge treatment

Sewage treatment

Sewerage

Sewer

Urban area (industries & residences)

River

Water distribution

Drinking water system

Purification plant

Water source

Agriculture, forestry, and stockbreeding

Rainfall

Rainfall

Lakes, marshes, and dams

(LOGACE series)Open monitoring logger

(FAINS-AX series)Open distributed monitor and control system

<Cost reduction>

BOD biosensorRainfall information systemOnsite power supplyEarthquake-proof design

<Emergency management>

Digestion-gas power generation

Heat pumpFuel cell

<Prevention of global warming>

Optical fiber network in sewers<Emergency management>

Trihalomethane analyzer

Water pressure regulation control systemService water quality monitor


Biosensor (acute toxicants monitor)


(LOGACE series)Open monitoring logger

(FAINS-AX series)

Open distributed monitor and control system

<Cost reduction>

Coagulation sensor

high-sensitivity turbidimeterOzone treatment system

Measures against cryptospori-dium

Rainfall information systemWater operation control system

Onsite power supplyEarthquake-proof design


Fuel cellSolar power generation

Small power generationCogeneration

<Prevention of global warming>

Sea


structure (equalization of loads) without increasing thetotal generated electric energy. This is one importantmeasure to realize so-called zero emission (reduction ofthe load due to human work on the global environmentto approximately zero).

Fuji Electric established “Fuji Electric’s basic poli-cy on environmental preservation” in 1992 and haspioneered technical development for problems of theglobal environment.

3.1 Activities for zero emission in water systemsRecently, unused energy and wide areas within

water facilities have attracted attention.Tubular and Francis water turbines are used for

hydraulic power generation, utilizing the effective headof water flow from reservoirs to purification plants.Fuji Electric has supplied many small hydraulic powerplants so far.

Through adoption of a cogeneration system thatutilizes exhaust heat, gas-turbine power generationraises total efficiency and is a superior energy-savingsystem. Fuji Electric, the first company to supply sucha system in the field of water and sewerage systems,delivered a gas-turbine power system to the Higashi-Murayama Purification Plant of the Tokyo WaterworksBureau.

Purification plants and water stations have wide-open spaces and hold promise for solar power genera-tion. Because the energy demand for water systems isgreater during the daytime than at night, solar powergeneration is advantageous. On the other hand, solarpower is dependent upon the weather, and therefore,interconnection with utility power supply or the addi-tion of a storage battery is necessary. Fuji Electric isaggressively making efforts to apply solar powergeneration to water and sewerage systems.

These onsite power systems are closely related notonly to energy problems but also to emergency man-agement. They must be considered as a lifeline in caseof a disaster such as an earthquake.

3.2 Activities for zero emission in sewerage systemsThe temperature of water from sewage treatment

fluctuates within a small range between 8 and 13°C.This small range is characteristic of a stable heatsource little influenced by climate.

An abundance of low-level energy has been dis-charged into the water during sewage treatment.However, technology for the efficient utilization of thislow-level energy had not been available until recently,and this energy had been referred to as “unusedenergy.” Recently, the appearance of heat pumps withhigh thermal efficiency has enabled the utilization oflow-level energy.

Digestive gas produced in the process of sludgetreatment has nearly the same degree of energy asurban gas. Highly efficient operation can be obtainedfrom gas-turbine power generation using digestion gas

as fuel and the heat recovered from a cogenerationsystem utilizing the gas-turbine exhaust heat. Fuel-cell power generation using digestion gas as fuel is alsopossible.

Fuel cells have higher power generation efficiencythan conventional gas turbines and diesel engines, andfuel-cell power generation combined with the utiliza-tion of its exhaust heat can increase the total efficiencyto 70 to 80%. Nitrogen oxides in the exhaust gas areas low as several ppm and the fuel cell is an excellentenergy source. Fuji Electric has marketed fuel cells,focusing on onsite phosphoric acid fuel cells.

4. Coping with Water Quality Problems

A recent buzzword regarding water systems hasbeen “safety” and people have displayed strong concernfor the removal or reduction of pathogenic microbesand harmful substances in raw water and of disinfec-tion byproducts in service water.

Early on, Fuji Electric started development ofvarious water quality analyzers to monitor watersystem safety and has prepared a line of new waterquality analyzers for analysis ranging from raw waterto tap water. These analyzers highly integrate chemi-cal, optical, and biological technologies with the physi-cal detection mechanisms used by most of the presentsensors, and have a high level of performance equiva-lent or superior that of the precise analyzers equippedin water quality test rooms.

4.1 Trihalomethane detection and reduction technologiesTo solve the problem of carcinogenic trihalom-

ethane currently receiving much attention, it is neces-sary to continuously monitor the amount generatedand increase of trihalomethane in service water andimplement measures to reduce the concentration belowthe permissible limit.

Biodegradation-resistant organic matter such ashumic acid and fulvic acid in river water is disinfectedby chlorine in the purification or sewage treatmentplant. This process forms trihalomethane as a disin-fection byproduct.

Fuji Electric developed a trihalomethane analyzercapable of continuous measurement of trihalomethanevalues in the purification and distribution processes ofwater systems, a simulation system for predictingincreases in trihalomethane formation, and a manage-ment system based on both of the above to reducetrihalomethane. These plant solutions can be realizedonly by integrating sensor, computer, and communica-tions technologies, and Fuji Electric is the only compa-ny in the world that possesses this original technology.

4.2 Sensor technology and river water quality managementsystemWhen there is a sudden abnormal change in water

quality, it is important to detect that abnormality as

Trends and Future Prospects of Water and Sewage Treatment System Technology 109

Fig.2 Block diagram for a wide-area water quality management system

soon as possible, determine measures to be takenbased on the abnormality conditions, and implementthose measures promptly. ITV monitoring of theintake and 24-hour observation by the staff of thebehavior of fish bred in a water tank have convention-ally been performed at water supply utilities as ameans of self-protection. However, monitoring by thestaff for an abnormality that may or may not occur atan unknown time is unreliable and uneconomical, andin particular, any reduction in night workers is aserious problem for the utilities. Therefore, there isstrong demand for automated detection of waterquality abnormalities. As abnormality occurrence hasspread over a wider area, the necessity for detectingpollution in the total water system and communicatingit to parties concerned has increased. In addition, theneed to provide decision criteria for the implementa-tion of countermeasures has increased the necessity ofriver-water quality management systems. Fuji Elec-tric has supplied river-water quality managementsystems composed of various water quality abnormali-ty detection sensors, data and picture transmissionequipment, various displays, database equipment, andpublic information and communication equipment.Figure 2 shows the system configuration.

4.3 Development of bioassayGenerally, the method of using biological material

and evaluating the biological response of an organismto a substance is called a bioassay.

The bioassay is a very effective method for the“evaluation of water toxicity to organisms,” “primary

screening of toxic substances” and “evaluation of theeffect of water treatment,” and has already beenapplied to drainage regulation and risk assessment inEurope and the USA. We suppose that its importanceas a new method of water quality evaluation willincrease also in Japan, adding to the conventionalmethods.

Fuji Electric will construct a database of biosensorsensitivity using microbes for various toxic substancesand will also develop a higher sensitivity bioassay thatcan detect harmful chemical substances with concen-trations as low as the chronic toxicity level. With this,we will establish a method for evaluating the influenceof chronic toxicity from extremely small amounts ofsubstances contained in drinking water.

5. Conclusion

Water and sewerage operations have a close rela-tion with regional and residential environments, andat the same time, have a social responsibility. Inaddition, utilities are required to quickly respond tosocial changes and needs.

Fuji Electric will continue its contribution into the21st century to the development of water and seweragesystems with the control and system technologies forwater treatment plants, developed in anticipation ofsocial needs.

In issuing this special edition, we would like toexpress our gratitude to the individuals and organiza-tion of the water and sewerage industry, and will begrateful for your guidance and support in the future.

DB

SP SP

Monitor center

Loudspeaker

Sound transmitter

Public information display

××h_××min Quality abnormal

Observation site BObservation site A


Oil film sensor


Oil film sensor

Water quality analyzers/pH,DO, BOD, etc.

Water quality analyzers/pH,DO, BOD, etc.

Infrared camera ITV

Image/data transmitter Image/data transmitter

Image, data & sound transmitter

Internethomepage

Publicity

Sound/message recording & reproduction

Publicity communication controlDatabase

Simulation and operations

Data processing

Maps/data display

Image transmission, control & display

Data transmitter

Data transmitter

Transmission to parties concerned


Yoshinori NagakuraMasayoshi TokuhiroKouji Akiyama

Modern Electrical Technology forWater Treatment Plants

1. Introduction

Global environmental problems such as globalwarming and acid rain originate from carbon dioxideand nitrogen oxide, which are generated mostly fromthe energy consumption of fossil fuels. To solve theseproblems there are two methods, one is to restrict theconsumption of fossil fuels and change to cleanenergy, and the other is to reduce energy consumptionitself.

This paper will introduce:(1) New energy technology and(2) Energy saving technologyavailable for the above-mentioned methods in watertreatment facilities, and(3) Recent initial electric power receiving, transform-

ing and powering equipment and their applica-tions

that support the above technologies.

2. New Energy in Water Treatment Plants

Most of the energy consumption in waterworksand sewerage facilities is electric power consumption.To reduce the power consumption it is effective toaccelerate application of dispersed power generationof new energy.

As alternative energy sources to fossil fuels, thereexists solar energy, hydraulic power energy, windforce energy and biogas (sludge digestion gas). Acomparison of the CO2 emission corresponding toeach of the power generation systems is shown in Fig.1.

2.1 Photovoltaic power generation systemIt is said that the amount of solar energy irradiat-

ed upon the surface of the earth for only 40 minutescan supply the energy consumed by mankind in oneyear. However, it is difficult to use this energy steadily

Fig.1 Comparison of power generation systems and CO2 emission

[Reference] Survey of Central Power Research Institute

Facilities and operationFuel

Generated energy during lifetime

(Facilities construction+Facilities operation+Fuel for power generation+ Methane leakage)

CO2 emission during lifetime

New energy

Nu

clea

rpo

wer

Geo

ther

mal

po

wer

Med

ium

an

d sm

all-

type

h

ydra

uli

c po

wer

Ph

otov

olta

ic

pow

er(f

or h

ouse

hol

d)

Ph

otov

olta

ic

pow

er

(for

bu

sin

ess)

Win

d fo

rce

Tid

al c

urr

ent

for

ce

Oce

an t

her

mal

en

ergy

Sol

ar t

her

mal

po

wer

LA

G t

her

mal

po

wer

Oil

th

erm

al p

ower

Coa

l th

erm

al

pow

er

CO

2 em

issi

on u

nit

req

uir

emen

t (g

-C/k

Wh

)

CO2 emission unit requirement (g-C/kWh)

300

250

200

150

100

50

03 to 665

1634343536

5840

1224

270

200

178

=


Fig.2 Basic configuration of photovoltaic power generationsystem

because its density is low and the quantity of powergeneration depends on seasonal and meteorologicalconditions such as sunlight and the weather. On theother hand, solar energy generates no atmosphericpollutants and no noise that can lead to disruption ofthe earth’s environment. Solar energy is a clean andquiet energy source that can be utilized anywhere onthe earth. The basic configuration of a photovoltaicpower generation system is shown in Fig. 2.2.1.1 Principle of power generation

A solar battery is configured with pn-junctionstructure, joining a p-type semiconductor with an n-type semiconductor, and a pair of electrodes forextracting electricity. When light is irradiated uponthe junction, electrons (negative charge) and holes(positive charge) are generated by the photoelectriceffect, and their movement creates an electromotiveforce between the electrodes.2.1.2 Application to water treatment plants

Because there is much available space at the upperpart of water treatment facilities, such as at a waterservice reservoir, and the energy consumption patternof water treatment is similar to the irradiation pattern

of solar energy, water treatment plants are highlyadaptable to energy applications. The main systemapplications are listed below.(1) A system linked to the electric power system(2) A system that independently operates as dis-

persed power generation using a storage battery(3) A system in which wind force power generation,

small-type hydraulic power generation, etc. areused in combination.

Proposed applications to a waterworks plant areshown in Table 1.

2.2 Small-type hydraulic power generation systemThis system converts the kinetic energy of water

into electricity, and the quantity of power generationis determined by the head and flow rate of the water.The advantages are listed below.(1) The construction is simple and compact in com-

parison with other power generation systems.(2) Power generation is practical if the water has a

head and flow rate.(3) Maintenance is unnecessary.(4) Among power generation methods, hydraulic pow-

er has the lowest emission of carbon dioxide.2.2.1 Applicability of small-type hydraulic power generation

Fuji Electric provides a series of models widelyapplicable for power generation with generated out-puts ranging from 50kW to several thousand kWs.Figure 3 shows a graph of power generation quantityrelated to the effective head and flow rate. Forexample, a head of 10m with a flow rate of 42m3/minallows a generated power of 50kW.2.2.2 Application to water treatment plants

Hydraulic systems can be employed in waterconduction and distribution systems of waterworksand in water discharge systems of sewerage systems.Hydraulic systems are highly adaptable to watertreatment plants because the variation in quantity ofboth the conduction water and the distribution wateris similar to that of the electric load in water treatmentplants.

DC AC AC

Pow

er s

yste

m

Filter, protective equipment, etc.

System connecting equipment

AC load

(Inverter)

DC-to-AC converter

Electricity storage equipment

DC load

Solar battery array

Sunshine

Table 1 Proposed applications of photovoltaic power genera-tion systems to waterworks and sewerage

Fig.3 Applicability of water turbine

10.1 101

10

100

1000

100

Francis turbine

Pelton turbine

Water turbine flow rate (m3/s)

Eff

ecti

ve h

ead

(m)

50kW

500kW

Available upper space is wide.

Features of waterworks and sewerage

™Upper space of water filtration basin, filter bed

™Upper space of first sedimentation, last sedimentation and aeration tank [Cover]

™Roof of facilities house

Installation location of solar battery

Applied photovoltaic power generation system

™Medium and large capacity facilities

™Connected to commercial power system (usually without storage battery)

Some facilities such as a service reservoir are located among mountains.

Detection elements for pressure, flow rate, water quality are scattered.

™Roof of facilities house™Special mounting

frame (such as a pole)

™Small capacity facilities

™Connected to commercial power system (Storage battery is used in case of power outage)


2.3 Wind power generation systemThis power generation system utilizes wind energy.

The advantages are listed below.(1) There is no emission of air pollutants.(2) Large-capacity power generation is possible.(3) Installation is practical if there is an average wind

speed of greater than 6 m/s.Factors to be considered when determining the

installation location are listed below.(1) There are no obstructions in the surrounding

neighborhood that would create turbulance in thewind flow. A laminar flow is best if possible.

(2) There is no radio wave interference such asmicrowave, radiotelegraphy and televisions sig-nals in the neighborhood.

The system configuration is shown in Fig. 4, and alist of customers to whom systems have been deliv-ered is shown in Table 2.

2.4 Biogas utilizing power generation systemBiogas systems include fuel cell and digestion gas

power generation that use biogas (digestion gas gener-ated in the sewerage plant) as the fuel. The fuel cellhas the following advantages.(1) Efficient high power generation.(2) Constituents of the discharged gas are clean

(NOx: below 5ppm, CO2: 60 to 70% of conven-tional generators).

(3) The overall efficiency reaches 80% by utilizing theheat generated from the process of its electro-chemical reactions.

2.5 Application of new energy systems to water treatmentplantsApplications of new energy systems to water

treatment plants are introduced below.2.5.1 Application of photovoltaic power generation system(1) Delivery example to the Murasakigawa Water

Source Station of the Waterworks Bureau of Kita-Kyusyu City

Fig.5 Overview of photovoltaic power generation system inMurasakigawa Water Source Station

Fig.4 Configuration of wind power generation system

System connection protection panel, etc.

Transformer panelCircuit breaker panelInverter panel

Windmill control panel (Inside of pole)

Telephone linePower company’s distribution line

Remote monitoring system

Load during disaster

20kW inverter panel

System connection protectionequipment

3-phase 3-line 210V

Transformer

3-phase 3-line 6,600V

1-phase 3-line 210/105V

Storage battery

20kW inverter10kW

inverter

House load

Murasakigawa Water Source StationDC DC

Commercial power system (Kyusyu Electric Power Co.)

Slow filtration bed

150kW Solar battery array

13

Table 2 Supply list of wind power generation facilities

Year delivered

1993

1994

1997

1997

1999 (planned)

Toyo Engineering Co.

Power Development Co.

NTT Facilities Co.

Tohoku Electric Power Co.

Shikoku Electric Power Engineering Co.

Yamagata PrefectureTachikawa Town

Wakamatsu Thermal Power Station

NTT Kumejima Radio Relay Station

Megawa Nuclear Power Station PR Center

Tohmen Co. Hokkaido Tomamae Wind Park

1000kW × 3

22kW

225kW × 1

Wind: 17.5kWSolar: 3kW

1000kW × 20

US Wind Power

Isobe Steel Co.(Darius type windmill)

Ebara Works

Yamaha Motors Co.Fuji Electric

BONUS

Fuji Electric

Fuji Electric

Fuji Electric

Fuji Electric

Fuji Electric

Hybrid system of wind and solar power

Customer name End-user name NoteSpecifications

Capacity Windmill/generator manufacturer

System connecting equipment mfr.


inverter and a storage battery, the system can be usedas an emergency power source. Growth of waterweedsin the slow filtration bed is prevented by the coveringeffect of the solar battery array.(2) Delivery example to the Ogochi Reservoir of the

Tokyo Metropolitan Waterworks BureauThe reservoir covers a vast area of a lake and is

suitable for the installation of a large-scale photovoltaicpower plant. It is believed that the growth ofwaterweeds due to water inflows into lakes, marshesand dams may influence the water quality. A systemthat operates on energy obtained from photovoltaicpower generation and maintains the water quality bysalvaging the waterweed, has been delivered to theOgochi Reservoir. The system configuration is shownin Fig. 6 and the appearance is shown in Fig. 7.

The generated outputs are 125kW from the land-based equipment, 25kW from the offshore equipmentand 1.5kW from the electrically driven vessel. Eachpiece of equipment is used jointly with a storagebattery to implement a hybrid system for disastersand emergencies.2.5.2 Application of small-type hydraulic power genera-

tion systemsAs application examples there are several plants of

various capacity from the 20kW micro-hydraulic tur-bine generator for the Tainai River of Niigata Prefec-

Fig.6 System configuration of photovoltaic power generation equipment in Ogochi Reservoir

Fig.7 Appearance of vessel for conveying salvaged waterweed

M

[OKUTAMA MIZUTO MIDORI NOFUREAI KAN ]For natural education

Exhibition facilities

Initial power receiving and transforming equipment

[Land based equipment]

Tokyo Electric Power Co.

Inverter for disaster

Battery charger

[Parking space]

Solar battery (Polycrystal type) 125kW

[Electrically-driven vessel “Hidamari” ]

Driving motor for electrically-driven vessel

Storage battery for electrically-driven vessel

Inverter

Inverter

Solar battery (Amorphous type) 1.5kW

[Offshore based water quality main-tenance equipment]

[Machine room]

Water quality maintenance device

[Kawano parking area of Tokyo Metropolis]

(Power supply for illumination)


(Power supply for illumination)


AC

AC

AC

AC

[Switch room]

DC to AC converter

DC to AC converter

DC to AC converter

Storage battery for powering and disaster

DC

DC

DC

DC DC

Solar battery (Polycrystal type) 25kW

Waterweed salvaging pump 2

AC to DCconverter

In this system, a 150kW solar battery array isinstalled at the upper side of the slow filtration bed,and DC electric power generated from the solarbattery is converted to AC with an inverter and usedas a power source after being connected to the initialelectric power receiving and transforming equipment.An overview of the power source system is shown inFig. 5. When a commercial power source is shut down,because of its self-sustaining function with a 20kW

A7530-19-19


Fig.8 840kW horizontal shaft Francis turbine hydraulic gener-ator for Ken’o 1st Waterworks of Gumma Prefecture

ture to the 840kW horizontal axis Francis turbinehydraulic generator (Fig. 8) for the Ken’o 1st Water-works of Gumma Prefecture.

The historical annually generated energy of thepower plant delivered to the Ken’o 1st Waterworks ofGumma Prefecture is 6,303MWh (an average outputof 755kW) and the utilization factor is high.

In a small-type hydraulic power plant, now underconstruction at the Higashi-Murayama Water Purifi-cation Plant of the Tokyo Metropolitan WaterworksBureau, an S-type tubular turbine is to be installed inthe existing conduit, and the power plant is to operatewhile connected to the power system of an electricpower company.

The generator will output a rated power of1,400kW and feed approximately 90% of the usualpower demand in the plant by parallel operation of 2sets of 2,000kW co-generating equipment. It is alsoplanned to use this system as an emergency powersource during service outages of the electric powercompany.2.5.3 Application of biogas utilizing power generation

systemsA system among water treatment plants generates

electricity by using the digestion gas originated in thesewage treatment plant as fuel. There is also a systemthat produces sodium hypochlorite by using the DCelectric power generated from a fuel cell directly forthe electrolysis of salt water.

3. Energy Saving Technology in Water Treat-ment Plants

3.1 Variable speed control systemPump or blower motors consume most of the

electric power in water treatment plants. Therefore,energy saving by these motors allows the whole plantto effectively conserve energy. Usually the pumps andblowers are manufactured at a rated capacity accord-

ing to the rated water (or gas) volume.However, the pumps and blowers are often driven

at less than their rated values. As a result, convention-al operation by driving at a fixed speed will restrainthe flow rate of discharge valves, etc. and thus someenergy will be lost in the discharge unit.

On the contrary, unnecessary energy consump-tion can be limited if the motor is driven with variablespeeds.

The primary frequency control system (VVVF:Variable Voltage Variable Frequency) and the second-ary excitation control system (Scherbius), variablespeed control systems used for energy saving in manywater treatment plants, are introduced in the follow-ing.3.1.1 VVVF with harmonic restrained PWM (pulse width

modulation) converterIn this system, the converter unit of a variable

speed controller (VVVF) used for driving 3-phase200V and 3-phase 400V squirrel-cage induction motorsis modified to the PWM type (sine wave input type).The advantages of this system are listed below.

Figure 9 shows the circuit configuration.(1) Countermeasures against harmonics are unneces-

saryBecause the current at the power source side is

made into a sine waveform by the PWM control, fewharmonics are generated.(2) Miniaturization is possible

Because the power factor control creates a currentflow that is in-phase with the source phase voltage,driving at a power factor of approximately 1 becomespossible, and thus the power transformer and otherapparatus can be miniaturized.

Fig.9 Circuit configuration of VVVF with harmonic restrainedPWM converter

M

IGBT

IGBT

Motor

Control signal

Frequency setting

Inverter unit

Control circuit

Control circuit

Converter unit

Power supply unit

Power source


(3) Maintenance is easyThe intelligent functions allow easy referencing of

fault histories, thereby simplifying the maintenance.3.1.2 Harmonic restrained PWM Scherbius

The Scherbius system controls the speed of a high-voltage wound-rotor-type motor by returning its sec-ondary power to the power source through an invert-er. Because a PWM inverter is employed instead ofthe usual thyrister inverter, this system has thefollowing advantages. The circuit configuration isshown in Fig. 10.(1) Countermeasures against harmonics are unneces-

saryControl at a power factor of approximately 1 is

possible, and the percentage of harmonic componentscan be limited to less than 5%, too.(2) Operating efficiency is high

Compared with the VVVF, the equipment capacity

of the inverter is approximately 2/3, the efficiency ofthe wound-rotor-type motor is higher than that of thesquirrel-cage type, and thus the running efficiency ishigher by about 2 to 3%.3.1.3 High-voltage direct drive VVVF

This system directly controls the speed of a high-voltage induction motor from a high source voltageusing high-voltage diodes and high-voltage IGBTelements. The advantages are as follows. The circuitconfiguration is shown in Fig. 11.(1) High-voltage motor is directly driven

A 3kV high-voltage motor can be directly drivenfrom a high source voltage. (A 6kV system will besoon introduced to the marketplace.)(2) Miniaturization is possible

A step-up transformer becomes unnecessary, andminiaturization and improved reliability are achieved.(3) Countermeasures against harmonics are unneces-

saryAdoption of a multiphase diode rectifying system

(3 × 12-phase rectification) eliminates the necessity forcountermeasures against harmonics.(4) Extended-life and reduced noise of the motor are

realizedStress to the motor is reduced, because the output

current waveform becomes almost a sine wavethrough employment of PWM control.(5) Maintenance is easy

Operations and failure diagnosis can be easilycarried out by the intelligent functions.

3.2 Energy saving controlThe usual energy saving operation of pumps is

implemented using a combination of the “number ofpumps” control and the “variable speed” controlcorresponding to increases or decreases of the flowrate and level of water. The resulting energy savingeffect is approximately 20%.

As methods to increase the energy saving effecteven more, two systems will be introduced here. Oneis the high-efficiency number of pumps control system,in which a pump head is used as the criteria to

Fig.10 Circuit configuration of harmonic restrained PWMScherbius

Detection of synchronized power source

AVRDDC controller

PWM inverter

Initial charging circuit

ASR+ACRDDC controller

DC chopper

Diode rectifier

Speed command

PG or TG

DCL

STMC

RNMC

6

52M 52C

+ACL

IM

Fig.11 Circuit configuration of high-voltage directly drivingVVVF

Same as above

Same as above

IM

Fig.12 Ideal operation region for high-efficiency number ofpumps

1 2 3 4 5 6 7

Flow rate

Hea

d


Table 3 Main energy saving apparatus in water treatment plant

Classification Apparatus name Summary Effect Misc.Application

Power equipment

Pumping equipment

Miscellaneous

Illumination equipment

Active filter

Demand controller

™Restricts loss and influence due to harmonics, such as overheat, noise, vibration

™Compensates reactive power

™Supervises control of contract demand

™Harmonics generat-ing apparatus such as variable speed controllers, non-interrupting power supplies, rectifiers

™Receiving point power demand

™Restricts overcurrent due to harmonics

™Reduces power charge by improved power factor

™Reduces contract demand

™Prevents excessive contract demand

™Reduced voltage drop and increased capacity factor.

Automatic power factor regulator

™Reduces ohmic loss due to reactive power

™Compensation of transformer excitation

™Induction motor

™Reduces power charge

™Reduces power loss

™Changeover operation of working number of units

™Operation at highest efficiency

Molded transformer

™Extensively reduces loss by core material and mold technology

™Initial power receiving and transforming equipment, powering equipment, illumina-tion equipment

™Compared with usual dry type, no load loss is reduced by approx. 2/3 and load loss by 1/2 to 2/3.

Variable speed controller VVVF

™Realizes high-efficiency operation by changing frequency and voltage

™General-use type squirrel-cage induc-tion motor ranging from 0.2kW to 900kW

™Reduces approx. 65%

of loss at 70% speed

™Apparatus lifetime is expected to increase also

Thyrister Scherbius

™Realizes high-efficiency operation by returning secondary slip power to power source

™Wound-rotor type induction motor from approx. 100kW to 5,000kW

High-efficiency motor

™Achieves high-efficiency by using latest design and low-loss material

™Induction motor ™Maintains high-efficiency at light load (above 50%)

Power saving device

™Saves excessive power by restraining excessive voltage to appropriate value

™Low voltage powering and illuminating equipment

™Reduces working power by 10 to 20%

LogoReduced stand-by power

™Applies Energy Star logo to energy-saving apparatus, according to International Energy Star Program

™Computer, display device, printer, facsimile, copy machine

™Widely used by most of OA devices

determine whether the number of pumps should bechanged. The other is the efficiency-increasing(equalizing) pump driving system, which uses thewater supply quantity determined based on predicteddemand.3.2.1 High-efficiency number of pumps control system

Energy saving for the whole plant is attempted bydriving the number of pumps that will result in thegreatest saving of electric power.

The electric power Pm at the time when m pumpsoperate to supply water at the flow rate Q and head His calculated and compared with the electric power atthe time when (m+1) and (m-1) pumps run. Then ifthe value of least power is chosen as the number ofdriving pumps, operation with the greatest powersavings can be achieved.

As shown in Fig. 12, the region corresponding tothe number of ideal driving pumps is established inadvance, and the number of pumps can be controlledby comparison to this region.

Employment of this system in a water purificationplant equipped with approximately 3,000kW of run-

ning pumps, an energy saving effect of 2% or more wasachieved in comparison with the conventional systemfor controlling the number of pumps.3.2.2 Efficiency-increasing (equalizing) pump driving

system by operation programThis system aims to save energy through limiting

the energy loss during pump changeover by reducingthe unnecessary suspension of pumping operation.

In such a water supply program, the watervolume required for a service reservoir is supplied inadvance based on predicted demand so that thepumps may be evenly driven, and changeover of therunning pumps is controlled.

Employment of this system can expect to yield anenergy saving effect of approximately 1% or greaterthan the conventional pump number changeover meth-od based on the water level of the service reservoir.

3.3 Energy saving apparatusSummaries of various energy saving electrical

apparatus and their effects are shown in Table 3, andtheir applied system configurations are shown in


Fig.13 System configuration of energy saving apparatus

Power saving device

High-efficiency motor

PWM converterActive

filter

Molded transformer

Capacitor

High-voltage directly driving VVVF

Automatic power factor regulator

Demand controller

VVVF

M

M

Fig. 13.

4. Recent Initial Power Receiving, Transformingand Powering Equipment in Water TreatmentPlants

Equipment recently used for initial power receiv-ing, transforming and powering facilities in manywater treatment plants will be described here.

As forms of extra-high-voltage substations, thereare steel structure types, housing types and gasinsulation types. Recently, the gas insulation typehas become frequently used since it allows substan-tially reduced installation space and high reliability.Fuji Electric has delivered this type to many foreigncountries including China and the Southeast Asiaarea.

4.1 Gas-insulated switchgear (GIS)This equipment compactly encloses charged parts

of circuit-breakers, disconnectors, instrument currentand voltage transformers, arresters, buses, etc. inseveral metal containers that are filled with SF6 gas (6fluorine sulfur gas), having excellent insulation char-acteristics, and are then sealed. Fuji Electric isproviding a series of GIS devices ranging from ratedvoltages of 72kV to 300kV and rated breaking currentsof 25kA to 50kA. SF6 gas insulation has the followingadvantages in comparison with a conventional airinsulation system.(1) Substantial reduction of onsite space is possible

The equipment is made compact in size, as variousindividual power apparatus are unified by SF6 gasinsulation.(2) Shortened fieldwork term and highly reliable

equipment can be achieved

The unit circuit modules can be completely assem-bled in the factory and then transported to the site.Therefore, the fieldwork can be finished by connectingonly the modules.(3) Maintenance can be reduced

Since the components themselves are enclosed inSF6 gas sealed containers, there is no need to worryabout degradation caused by pollution and oxidation.The age deterioration of parts is also much decreased.(4) Harmony with environment is obtained

There are no steel supports as in substations withair insulation systems and the appearance is excellent.(5) Safety is high

Every container is completely grounded and thereis no fear of electric shock.4.1.1 Front access type GIS (72/84kV)

Under the concepts of “more compactness”, “easi-er use” and “greater safety”, further miniaturization,front access and completely oil-free equipment areachieved.(1) Installation area can be extensively reduced

The skeletal diagram and comparison with aconventional device are shown in Fig. 14. The mount-ing area is extensively reduced by about 50% in thecase of a 2-circuit, 2-bank and 1-VCT system.(2) Maintainability is drastically improved

As shown in Fig. 15, all the manipulating andmonitoring functions such as manipulators, monitor-ing instruments and gas components are mounted onthe front panel of the equipment. There is no need toturn the equipment to access the side or the back.Thus, daily maintenance can be performed as if thiswas an ordinary switchboard.(3) High safety

Completely oil-free equipment is achieved bymaking electrically-driven spring-manipulation typecircuit breakers.4.1.2 Super-miniaturization by replacing extra-high-

voltage circuit-breaker with vacuum circuit breaker(VCB)

The gas-insulated switchgear is super-miniatur-ized by replacing the usual 72/84kV gas circuit breakerwith a vacuum circuit breaker. This also achieves acost reduction.

4.2 Digital multi-function relayThe digital multi-function relay is an integrated

compact module with functions of protection, manipu-lation, instrumentation, monitor and transmission forinitial power receiving and distribution facilities, andhas the following advantages. Table 4 shows thespecifications and Fig. 16 shows the appearance of therelay.(1) System is readily made intelligent

With its transmission function, the relay canconnect to upper level computers through a network.So in addition to the normal operation and supervisorycontrol functions, intelligent functions such as support


Fig.14 Space comparison of front access type GIS

Front access type GISConventional type GISSkeletal diagram

VCT

Fig.15 Appearance of front access type GIS

of the operation and maintenance are readily achieved.(2) Fault analysis is easy

Data at the occurrence of a fault such as currents,voltages, zero sequence currents, zero sequence volt-ages, etc. are automatically preserved and the instru-mentation results can be displayed in the relay itself.Fault analysis is easy, even at a central location, byviewing the transmitted fault data.(3) Reduced labor for maintenance

In addition to the continuous fault monitoringfunction of the relay itself, the relay is provided withan automatic checking function which verifies accura-cy of the analog input parts and responses of theoutput relays, and a circuit breaker monitoring func-tion which observes breakage of trip coils and open-ing/closing times of the circuit breakers. This achievesa reduction in the labor for maintenance.

4.3 Intelligent control centerThe intelligent control center is a multistage

stacked power board that is a modified conventionalcontrol center made highly functional and intelligent

by replacing its control unit with an electronic unit.The intelligent control center has the following advan-tages and its specifications are listed in Table 5.(1) Extensively reduced external wiring and short-

ened construction periodBecause the equipment has a transmission func-

tion, a total networked system can be built rangingfrom upper level systems, such as PLCs (programma-ble logic controllers) and CRT supervisory controllers,to the fields of local operator panels. This enableshigher maintenance with detailed data, extensivereduction in the number of external wires and ashorter onsite construction period.(2) Faults are preventable

The protection performance is dramatically en-hanced by new functions such as an overload pre-alarm, ground fault pre-alarm, detection of blockedopening/closing of MCs (magnet contactors) and detec-tion of abnormally configured MC main circuit, togeth-er with conventional functions such as overload, openphase, ground fault, instantaneous overcurrent andundercurrent protection. This enhanced protection

Fig.16 Appearance of digital multi-function relay

AM180975 N99-2332-4


Table 4 Function list of digital multi-function relay ○ : With function, － : Without function

Item

Instrumentation functions

Current value indication (A) － ○

Voltage value indication (V) ○ －

Zero sequence current value indication (MA0) － ○

Zero sequence voltage value indication (MV0) ○ －

Power value indication (W) － ○

Reactive power value indication (var) lag power factor － ○

Power factor indication (cos ) － ○

Frequency indication (Hz) ○ －

Watt-hour indication (Wh) － ○

Fault record (measured value at fault) indication MA, MA0

MV, MV0

－ ○

○ －

Open/close manipulation of line switch

Control functions

－ ○

Remote/direct changeover (control right) － ○

Open/close remote control (external contact and transmission) － ○

Short circuit protection (INST: instantaneous)

Protection functions

－ ○

Overcurrent protection (OC: inverse time-lag) － ○

Directional ground protection (DG) － ○

Overvoltage protection (OV) ○ －

Undercurrent protection (UV) ○ －

Ground overvoltage protection (OVG) ○ －

Voltage recognition (VR) ○ －

Remote trip (external trip) － ○

Reverse phase and open phase － ○

Relay setting value indication

Display functions

○ ○

Relay operation indication ○ ○

Line switch status indication － ○

Control right status indication (remote/direct) － ○

CB trip coil breakage monitoring Monitoring functions (maintenance support)

－ ○

CB opening/closing time monitoring － ○

Constant monitoring function

Self-diagnostic functions

○ ○

Automatic checking (initiated at fixed cycles every 24 hours) ○ ○

Manual test (initiated anytime) ○ ○

Lamp test ○ ○

Forced operation (each element individually) ○ ○

Reception of line switch open/close signals

Transmission functions (T-Link) Only for types with T-Link

Transmission of measured value data to upper system

Transmission of protective relay operation signals to upper system

Transmission of setting values of protective relays and timers to upper system, and reception of setting values

Transmission of line switch status indication signals and control right status indication (remote/direct) signals to upper system

Transmission of switchgear side signals (CB draw-out position, etc.) to upper system

Transmission of system failures and ID data to upper system

Content Bus unit Feeder unit (shared combination unit)

φ

performance allows the prevention of faults.(3) Switch room space is saved

The direct connection of control signals with PLCsthrough transmission lines eliminates the necessity forinstallation of conventional auxiliary relay panels, andthus space saving of the switch room can be achieved.

5. Conclusion

New energy technology and the energy savingtechnology have been introduced and applications towater treatment plants have been explained. It will be


Table 5 Function list of intelligent control center

Item

Applied circuit

Protection

Monitor, display

Inverter, 1-phase or 3-phase general low-voltage load with inching manipulation

OverloadOpen phaseDirection groundInstantaneous overcurrentUndercurrentOverloard pre-alarmDirection ground pre-alarmMC fault

Monitor display

™Load current™Leakage current™Fault current™Fault condition™Setting value™Operating record

OperationManipula-tion Instrumenta-

tion, setting

™Selector switch: REM-DIR-TEST™Push button switch: ON, OFF, REV

™Push button switch: MODE SELECT, SET/FLT, RESET, ∧, ∨, ENTER

™Main circuit: Automatic setting (Non-reversible, reversible, power source feed)

™Control circuit: 256-pattern

™Compensation time: 0.5 to 5.0 s (in 0.5 s steps)

™Restart: 0 to 60 s (in 1 s steps), Instant restart if interruption is shorter than 0.2 s.

™Control signal: 4-point (88F, 88R, interlock, external fault)

™Manipulation signal: 4-point (ON, OFF, REV, center)

™Operation signal: 3-point (ON, OFF, REV)

™Fault signal: 2-point (Element can be selected)

™Contact capacity: Rated current 1 A, maximum switching capacity 250V AC, 5A

Sequence

Control

Restart after momentary power inter-ruption

Input

Output

Content Item

TEST mode

Test

CPU self-diagnosis

™Protection function: Overload, ground fault

™Control function: Center (via transmission), onsite, MCC

™Normally: CPU monitor, Communication monitor

™During operation: ROM monitor, RAM monitor, EE-ROM monitor, Analog input value monitor

™During test: Analog input value monitor

™F-NET: Normally provided with T-Link

™Transmission rate: 500kbs™Transmission distance: 1km™Transmission line:

2-wire twisted pair cable™Number of terminals that can be

connected: 32/1-link to 128/4-link

System

™Transmission quantity: Digital 26-items, analog 4-items

™Data contents: Operation signal, fault signal, measured value, setting value, present value of operation record

Transmission data

™Reception quantity: Digital 22-items

™Data contents: Operation signal, setting value, initial value of operation record

Receptiondata

Transmis-sion

Content

Memory

Fault current

Setting value ™All setting items

Operation record

™Operating time™MC close/open™Trip™Overload™Open phase™Ground fault™Instantaneous overcurrent™Undercurrent™External fault™Momentary interruption restart™MC failure™Maximum load current™Minimum load current

™Overload: 0 to 1000%A™Ground fault: 0 to 500mA

™Protection: CT rating, rated current, overload protection mode, instantaneous operat-ing current of overcurrent, instanta-neous operating time of overcurrent, operating current of undercurrent, operating time of undercurrent, ground fault sensitive current, ground fault operating time, ground fault changeover, open phase protection valid/not valid, overload pre-alarm operating current, ground fault pre-alarm operating current, overload protection reset method, starting lock time

™Control: Momentary interruption compensation time, momentary interruption restart time, sequence number, application sorting of fault output contact, process-ing during CPU error

™Transmission: Transmission address, processing during upper system error

™Operation record: Initial value™Setting protection:

Provided with locking function of setting value

ItemSetting

appreciated if this information is helpful in theimplementation of measures to counteract environ-mental problems, such as reducing fossil fuel consump-tion by accelerating applications of new energy andenergy saving apparatus. Although the new energy

technology still has some subjects that should beimproved upon in the future, such as cost reductionand higher efficiency, Fuji Electric will continue tomake efforts to provide systems in response to require-ments of the age and society.


1. Introduction

Japan has built up a rich social framework in anenvironment that has been blessed with the benefits ofwater. A close relation between the utilization ofwater resources and social activities has always beenmaintained. Recently, the water quality of drinkingwater resources, rivers, lakes and marshes, has de-graded year-by-year due to advanced industries, higherliving standards and concentrated population. Inaddition, water shortages due to a lack of rain becauseof global climactic abnormalities are also makingunfavorable circumstances for water volume. On theother hand, waterworks, which form the basis for ourstandard of living, are becoming more widespread anda stable supply of high quality “safe and good tastingwater” is required for the coming 21st century.

Responding to such needs of the times, Fuji

Kouju Miyairi

Instrumentation, Control andSensor Technology for Waterworks

Electric has contributed to problem solving with vari-ous system technologies - energy, plant, process andEIC (Electricity, Instrument and Computer) systems -which have been cultivated for many years in the fieldof waterworks.

This paper will introduce new water quality sen-sors and original process control and instrumentationsystems for waterworks that respond to the latestwater environment changes.

2. Sensors

System technology that has responded to waterquality changes is represented in the newly developedwater quality sensors. Figure 1 shows the relationbetween the process flow of waterworks and the waterquality sensors.

Fig.1 Relation between process flow of waterworks and water quality sensors

Mixing tank

Intake

Flocculation basin Sedimentation basin

Ozone catalysis tank

Active carbon adsorption tank Filter basin

Service reservoir

Water supply facilities

Water quality safety monitorCoagulationsensor

High-sensitivityturbidimeter

Water purification plant

Control room

Trihalomethane analyzer

Service water quality monitor


2.1 Water quality safety monitorTo verify the safety of a water source, fish are

generally kept in raw water and their behavior ob-served to determine if any abnormality exists in thewater. This method has such problems as ambiguityin the observation of fish behavior and the laborrequired to constantly maintain the many fish in ahealthy condition. Thus, another automated methodhas been required. With a dissolved oxygen electrode,the water quality monitor introduced here directlydetects reduced respiration activity of bacteria (nitrify-ing bacteria) sensitive to acute toxicants in water, andissues an alarm. This monitor is not capable ofdetermining toxicants but automatically samples wa-ter for inspection if any toxicant is infected, and thisallows the toxicant to be identified later with a preciseanalyzer.

2.2 Coagulation sensor and controllerIn the coagulation-sedimentation process, an im-

portant treatment in water purification plants, thecoagulant injection rate is largely determined based onraw water quality or the manual analysis of a jar test,however satisfactory results have not been achieved inmany cases when the raw water quality suddenlychanges. Based on the fluctuation in absorbance ofirradiating light, the coagulation sensor and controllermeasure the mean diameter of flocculated particles inmixing tanks and flocculation basins of the waterpurification plants. The controller performs optimizedcoagulant injection control.

2.3 High-sensitivity turbidimeterMass infection of the pathogenic organism

cryptosporidium occurred in 1996 in the Kanto districtof Japan, and the pollution source was believed to becity water. The Japanese Ministry of Health andWelfare issued then tentative guidelines for cryptospo-ridium that required the turbidity in the effluent froma filter basin to be kept under 0.1 degree. Followingthese guidelines, Fuji Electric has developed a newtype of high-sensitivity turbidimeter. Utilization of thefront light scattering particle counter method hasallowed this turbidimeter to measure the super-lowturbidity of 0.001 degree, impossible for the conven-tional transmitting light method and the surface lightscattering method, and to simultaneously measureparticle size distributions (0.5, 1.0, 3.0 and 7.0µm orgreater). In the field of waterworks, this highly precisehybrid turbidimeter will be a critical device for a newepoch.

2.4 Trihalomethane analyzerAs treated in the new water quality standards,

monitoring the concentration of trihalomethane in citywater is extremely important because trihalomethaneis feared to be a carcinogen. However, gas chromatog-

raphy, an existing analyzing method, requires skilland time because of its complicated pretreatment andis incapable of continuous measurement by batchprocessing. Thus, a simpler and faster measuringanalyzer has been desired. This trihalomethaneanalyzer is for laboratory use and analyzes quickly andautomatically the total trihalomethane in sampledwater with a fluorometry method based on the Fuji-wara Reaction.

2.5 Service water quality monitorIn Japan, automated daily inspection of the water

quality (pH, turbidity, color, residual chlorine, electricconductivity, water temperature and water pressure)as prescribed in the waterworks law is coming intowidespread use mostly in large cities, but a color meterwhich only identifies some colors has been used as asubstitute for the color inspection. In coordinationwith the Japan Water Works Association, Fuji Electrichas developed the world’s first monitor that is capableof identifying all hues. This monitor can detect colorgradations of city water such as red water, white waterand black water and has a performance equivalent tothat of human eyes. The monitors are placed atmultiple points along a water distribution network.Obtaining real-time data by continuous monitoring hasenabled the realization of advanced water manage-ment such as ensuring the safety of service waterquality and preventing expansion of damage due tofaults or disasters by centralized monitoring, andmonitoring the flow time from the water purificationplant by continuous measuring of water pressure, pHand residual chlorine concentration.

3. Process Control Technology

Water management and control represents a tech-nology for handling changes in the water volume. Thephrase “water management” often refers to waterintake management, water supply management andwater distribution management, and here water man-agement and control shall cover these three wideareas.

3.1 Water supply management and controlThe principle objective of water supply manage-

ment and control is to economically and effectivelydistribute the water volume from a water intake to aservice reservoir. Figure 2 shows an overview of watersupply management.(1) Water demand prediction

The prediction of water demand forms the basis ofwater supply management. Daily demand is predictedfor each service district, and based on the results, thewater distribution for all the water purification plantsand intake stations in a city is determined. Moreoverthe hourly demand is predicted by calculation from thepredicted daily water volume, and then the hourly


supply water volume to service reservoirs is planned.An online processing flow of the demand prediction isillustrated in Fig. 3.(2) Optimum water volume distribution

The supply water volume from each water purifica-tion plant is determined when the demand of eachservice district is planned. The supply water volumeplan is prepared such that the management cost isminimized when the water intake capacity, waterpurification capacity and water supply capacity of eachwater purification plant are limited. The watervolume distribution can be determined to minimize thetotal limited volume of service water during a watershortage. It is possible to examine the water manage-ment plan and to quickly respond to abnormalitiessuch as contamination of the source water by atoxicant.

(3) Service reservoir managementWhen hourly changes in the water volume from a

service reservoir are predicted, it is possible to level offthe supply water volume to the service reservoir and todevise a supply water plan for minimizing the numberof changes to running supply water pumps. Everyapproach is combined to optimize each service reser-voir. If the service reservoir receives water via thesupply water pumps, the number of running pumps iscontrolled, and if water is received via the inflowvalves, water inflow control (stepwise or continuous) isperformed.(4) Water management support simulation

The water management plan for maintaining sta-ble service water volume and pressure is designedunder variously assumed conditions in normal andabnormal circumstances, and simulation of the resultsis performed.

(a) Online simulationThe water level variation of each basin is calculat-

ed using the online data (present water level, plannedwater volume and predicted water demand) at the timeof the simulation. Simulation is also performed withmodified settings for the change of the planned watervolume

(b) Water management planning simulationSimulation of abnormal circumstances, modified

distribution systems or facilities, and for the optimumadjustment of water management plans can be per-formed under flexible conditions.

3.2 Water distribution controlWater distribution control mainly aims to reduce

the quantity of leakage by adjusting water pressure, toevenly serve water during a water shortage, and tomaintain the safety of water quality.(1) Pipe network calculation

The pipe network calculation is a basic analysismethod in water distribution control. This methodcomputes the water pressure and flow distribution in apipe network with given network parameters (pipenetworking topology, demand distribution, etc.), and isused to design pipe routing at new installations orduring renovation.(2) Selection of water pressure monitoring point

Based on the result of the pipe network calcula-tion, the pipe network is broken into several blocks andwater pressure monitoring points are set up at one ormore positions in each of the blocks. If there aremultiple positions, the block area is divided to obtainthe most effective allocation according to cluster analy-sis utilizing the similarity of water pressure variations.Then, monitoring points are selected at the positionswhere there is a large influence and where there islittle influence on the water pressure of the pipenetwork.(3) Distributed water pressure control (water pres-

sure adjustment)

Fig.2 Overview of water supply management

Waterdistribution

Service reservoir

Watersupplyingpump

Waterconveyingpump

P P

Clean waterreservoirmanagement

Servicereservoirmanagement

Hourlydemandprediction

Waterpurificationplanning

Water supplyplanning

Waterintakeplanning

Waterpurificationplant

Waterintakestation

Dailydemandprediction

Optimum watervolumedistribution

Fig.3 Online processing flow of demand prediction

Predict hourly water demand

Predict daily water demand

Distributionpattern file

Modify parameters of dailydistribution pattern withprevious day’s data

Predictionmodel file

Modify prediction modelparameters with Kalman filter

For eachdistribution area

Input predicted weather and maximumtemperature on that day and actualweather and maximum temperatureof previous day

Data file ofactual waterdistribution

Computational processingof the previous day’s actualdata for each distribution area


Fig.4 The latest waterworks management system

Service water quality monitor(pH, turbidity, color, etc.)

Service water quality monitor(pH, turbidity, color, etc.)

Solar battery

ISDN network, public telephone network, private optical fiber network

Pipe network(Pressure)

Safety monitoring of raw water(Toxicant sensor, ITV)

Slave station Slave station

Private line Microwave radio

Communication control equipment

Local area network for controlService reservoir, water intake station dataWater purification plant data

Local area network forinformation

Supervisory control computerDB

DB

Monitor CRT 2

Monitor CRT 1

World wide web computer

Open information computer

Router

Router

Water quality equipment

Waterqualitywork station

Watermanagementterminal

Water management work station

Shared information computer

Internet

City residents

Intranet of Water Bureau

Water Bureaumaintenance section

Base station

PHS communication

Personal cellular phone

Mobile terminal

Water pressure control adjusts the water pressurein each of the blocks with the water pressure adjustingvalve for that block. All the logical control isimplemented by onsite digital regulators. However,the water pressure setting of each block is determinedby a central computer or an operator and transmittd to each onsite regulator.(4) Water distribution control support simulation

A water distribution control plan is designed undervarious assumed conditions of normal and abnormalcircumstances, and simulation of the results is per-formed.

(a) Water pressure adjustment simulationFor fair and appropriate service water volume

under normal and abnormal circumstances, this simu-lation obtains the operating information for waterpressure adjusting valves and control valves from themutually given data of service water volume, second-ary pressure, end pressure and valve openings.

(b) Pipe network management simulationUnder mostly abnormal conditions, this simulation

performs economical management by modifying bound-aries of the distribution areas.

(c) Calculation of effect of water pressure adjust-ment

The effect of reduced service water volume byadjusting water pressure is calculated.

(d) Analysis of residual chlorine concentrationThe distribution of residual chlorine concentration

at service reservoirs and water faucets is estimated bycalculating consumption of the residual chlorine con-centration in the pipe network.

3.3 Example of water management systemWater supply management has been mostly intro-

duced into big-city areas such as Tokyo Metropolis,Osaka Prefecture, Kanagawa Prefecture, YokohamaCity and Kobe City. In many supervisory controlsystems for water purification plants, the function ofwater supply management is included in the supervi-sory control of external facilities. On the other hand,water distribution management is mainly applied inregional cities such as Matsuyama City, TakamatsuCity, Kumamoto City and Matsumoto City. To realizewater distribution control, some initial investmentsuch as dividing the pipe network into blocks andproviding onsite facilities is still required depending onthe scale of the waterworks plant.

In Matsuyama City, time limitations were placedon the feed water during the water shortage of 1994.


At that time, water distribution control with automaticpressure control valves was implemented in 77% of allthe districts and played an important role in thecountermeasures against the water shortage.

4. Instrumentation System Technology

Sensor and process control technologies have beenintroduced as system technologies for waterworkscountermeasures against water pollution and watershortages or leaks. Of the instrumentation systemtechnologies that comprehensively manage the afore-mentioned technologies, this section will describe thetechnologies most easily affected by disasters, datatransmission and power supply technologies.

Figure 4 illustrates an example of an instrumenta-tion system configured with the latest technologies.

4.1 Data transmission(1) Communication line

Selection of a communication line is important inthe configuration of an instrumentation system. Theline should actually be selected on the basis of cost-effectiveness after sufficient study of the geographicalcondition, regional characteristics (whether radiowaves can be received, or whether any telephone linesare near) and reliability (especially in disasters), aswell as performance (transmission speed, capacity,etc.)(2) Network technology

Use of the internet or intranet is effective forinformation exchange (supervisory control data, main-

tenance and management data) between the cityresidents and related sections of the WaterworksBureau. In case of an emergency such as an earth-quake disaster, the personal handy-phone system(PHS) is necessary for obtaining accurate onsite infor-mation. On the other hand, employment of a generalpurpose LAN and a standard communication protocolallows different companies to be linked with each otherthrough routers and exchange information between thesupervisory control system and other related systems.

4.2 Power supply technologyPower supplies are especially important, along

with transmission lines, for information communica-tion during disasters. As a countermeasure againstpower failures, uninterruptible power supplies (UPS)are required for sensors, transmission systems andcomputer systems. Utilization of solar batteries is alsounder consideration as emergency power sources forthe water quality monitors placed in pipe networkswithin a city.

5. Conclusion

System technology that responds to changes in thewater environment, together with global environmen-tal problems, will become increasingly important in thefuture. Fuji Electric will continue to provide varioussystem technologies for the effective utilization oflimited water resources and supply of safe and goodtasting water. We will strive to create a waterworkstotal management system suitable for the informationsociety of the 21st century.


Jun Umetsu

Instrumentation, Control andSensor Technology forSewage Treatment Plants

1. Introduction

Many sewerage facilities are being built recentlyand their use is becoming more widespread. Thetechnologies used in these facilities, such as sensors,instrumentation systems and control systems, is alsoimproving day-by-day. This paper will describe theselatest technologies for sewerage facilities.

2. Sensor

A sensor is equivalent to the human sense of sightand hearing. Various types of sensors are used insewerage facilities to measure water flow, waterpressure, water level and water quality. These sensorsare expected to be improved upon in the future, withadvanced precision and easier maintenance.

On the other hand, new principles of instrumenta-tion have been put to practical use, and the develop-ment of various new sensors is promoted. These newsensors for sewerage facilities will be described below.

2.1 BiosensorThe biosensor is a type of sensor that employs a

molecule identification function for biomaterials (en-zyme, microbes). The measuring method utilizes thecharacteristics of biomaterials that catalyze the reac-tion of a specific chemical substance, and detects withan electrode the change (consumption, generation) inthe chemical substance passing through a biomaterialimmobilized membrane. The configuration of theenzyme sensor includes the enzyme-immobilized mem-brane, an electrode transducer and a simple module.

Some biosensors have been already used in thefield of medical care to measure blood sugar values andin the field of food. In the field of the sewerage, awater quality meter that uses a nitrifying bacteriabiosensor and other water quality biosensors for sens-ing ammonia, nitrogen and phosphorus is now underdevelopment. Biosensors are expected to be usedwidely in the future.

2.2 Coagulation sensor for sewage dehydrationTo efficiently, steadily and continuously process

sludge generated from sewage treatment, determina-tion of the following is necessary: the type of dehydra-tor, the type of coagulant compatible to properties ofthe sludge and performance of the dehydrator, and acoagulant injection rate suitable for the concentrationof desiccated solids (SS concentration) in the sludge.

Fuji Electric is now developing a coagulant injec-tion control system for sewage dehydration. Corre-sponding to changes in the condition of the sludge, thesystem automatically and continuously controls onlinethe injection of coagulant by using a coagulation sensorfor sewage dehydration.

The measurement principle of the coagulationsensor utilizes the analysis method of infrared absor-bency fluctuation. The coagulation sensor computesand outputs a volume factor by irradiating far-infraredlight to an object and then calculating the meandiameter and numeric concentration of flocculatedparticles in that object from the degree of lightabsorbance.

3. Instrumentation System

During the treatment process at sewerage facili-ties, various quantities such as water level, pressureand water quality, including flow rate, are measuredand the systems that monitor and control such quanti-ties are configured. These latest systems for thesewerage will be described below.

3.1 Optical instrumentation technologyWith the development of low-loss optical fiber in

1970, the application of optics to instrumentationtechnology suddenly became a leading field of hightechnology. Optical instrumentation technology isroughly divided into (1) measurement with appliedoptics and (2) optical measurement using optical fibers.The former category includes point sensors such as theturbidimeter, infrared thermometer, Fourier transfor-mation infrared analyzer, and image sensors for vision-sensing robots and quality inspection or the selectionof goods. The latter is an instrumentation system thatuses optical fiber cable instead of conventional copperwire. Use of optical fibers has given this technology

Instrumentation, Control and Sensor Technology for Sewage Treatment Plants 127

broadband characteristics and resistance to lightning,noise and explosions, resolving various problems thathad previously held back this technology.

Figure 1 illustrates the optical field bus system inwhich the FFI system, developed as the world’s firstoptical fiber instrumentation system, is even moreopen. The sophisticated sensors use microcomputersand their output signals are transmit in digital form.

The advantages, as compared with conventionalsystems, are as follows: (1) resistance to noise (light-ning surge, electromagnetic induction), (2) intrinsicallysafe explosion-proofing, (3) high accuracy throughdigitization, (4) realization of self-diagnostic functionsand centralized maintenance (remote adjusting from acentral location), (5) reduction in the number of cables

Fig.1 Optical field bus system

Optical field bus sensors

Reflective starcoupler

Optical fiber cable

O/E converter

Controller

LAN

Field bus configurationsupport tool

(Operator station)

Fig.2 Centralized monitoring and distributed control system

(Sludge disposal plant)(No. 2 water treatment plant)(No. 1 water treatment plant)(Power supply equipment) Sensor

Control centerInstrumentpanel

Powersupplypanel

ACS-2000controlstation

HTLT LKP

SQCDDC

Sensor

PRPRHC


C/C RY LKP

SQCDDC

Sensor


C/C RY LKP

SQCDDC

Sensor


C/C RY LKP

SQCDDC

LAN

LAN

PC serverAOS-PCPersonalcomputer

(Control room) Network printer Hard copy

by using a star coupler, (6) simplified operation(allowing mixed communication cables with powercables in the same cable root), and (7) an open(internationally standard) multi-vendor network.

3.2 Network systemThe sewerage facilities have equipment both inside

and outside of the treatment plants and networksconfigured for the exchange of information and controlamong facilities.3.2.1 Local area network

A local area network is used to transmit informa-tion as well as instrumentation and control signals foreach piece of equipment inside the plant. Using a localarea network, many treatment plants employ a cen-tralized monitoring and distributed control system asshown in Fig. 2.3.2.2 Regional network

Network systems using telephone lines and opticalfiber cables are employed to transmit the instrumenta-tion and control signals of wastewater booster pumpstations scattered throughout a wide area and of mainline flow rate measuring equipment, and to performcentralized monitoring in the treatment plants.(1) Small-scale monitoring system

This system monitors and transmits data at fixedtime intervals using an ordinary public telephone lineas shown in Fig. 3. The cost performance of thissystem is enhanced through partnered managementwith neighboring towns and villages.(2) Remote supervisory control system

This system performs supervisory control withdata loggers and CRTs of a remote monitor office bycontinuously transmitting instrumentation and controldata via the private line of a telephone company asshown in Fig. 4. Many such systems are commonly and


Fig.5 Optical fiber network system

widely employed at present.(3) Optical fiber network system

Systems have recently been employed that ex-change data through optical fiber cables laid inunderground sewerage pipes. This allows constructionof a wide area network along with the sewage pipingnetwork, and implementation of advanced informationexchange. Features of such networks are listed below.① Does not require construction of a special path

because vacant space in the sewage pipes canbe used.

② Resistant to disasters and faults and thereliability is high.

③ Can exchange information that is highly denseover a wide area.

These networks are expected to play a big role inthe future information society.

The system configuration employs the aforemen-tioned optical field bus system or an Ethernet asshown in Fig. 5.

3.3 System power sourceA good-quality power source is necessary to nor-

mally run the aforementioned network. A UPS(uninterruptible power supply) is often used as thepower source of the network.

4. Process Control

The appropriate control is performed in eachtreatment process of the sewerage facilities. Therecently used new control systems will be describedbelow.

4.1 Advanced controlPID control is extensively used even now for lower-

order single loop control. However, there is a limita-tion on its application to higher-order systems orremarkably non-linear systems such as a time variablesystem with large dead time, multivariate systems anddistributed constant systems. (It can be said that thewater treatment process essentially has these charac-teristics.)

With the utilization of digital controllers, higher-level control systems came to be extensively used.Along with advances in modern control theory and inapplications to control technology, the application ofsuch advanced control methods to process control hasbecome possible by utilizing the functions of computersand these controllers. The various control systemsthat aim at such high-level control are commonlyreferred to as advanced control systems.

Fuzzy-logic based control is performed in thewastewater pump station of the sewerage facilities.

Fig.3 Small-scale monitoring system

(No. 4 station)(No. 3 station)(No. 2 station)

(No. 1 station)

Transmissionequipment




Public telephone network

Printer

Personal computer

MODEM

MODEM

DI , AI

TLM

MICREX-F70

(Control room)

PR

Fig.4 Remote supervisory control system

(No. n station)(No. 1 station) (No. 1 station)

SAS-50Telemeter/telecontroller

AIDI

AODO

Private line

ASA-2000Telemeter/telecontroller

TM / TC TM / TC TM / TC

(No. n station)

TM / TC

TM / TC TM / TC

LAN

PC serverAOS-PCPersonal computer

(Control room) Network printerPR PR

Field sensors

Camera

Optical datagatheringequipment

Controller

(No. 2 pump station)

(No. 1 pump station)

Optical fiber cable

E/O, O/Econverter

E/O, O/Econverter

Ethernet switch

Field sensors

Camera

Optical datagatheringequipment

Controller

Optical fiber cable

E/O, O/Econverter

E/O, O/Econverter

Ethernet switch

Ethernet switch

(Control room) Printer Personal computer PR

Instrumentation, Control and Sensor Technology for Sewage Treatment Plants 129

With fuzzy-logic control, controllers are used to provideproper pump and gate control by: subdividing theprocess of inflow control into several control rules(previously a task which only skillful operators couldperform), judging the circumstances based on rainfallintensity and pump discharge, and understanding thevariation rate of the water level.

4.2 Application of AI (artificial intelligence)Research on AI and its application has centered

around the United States since the 1960’s. Since the1980’s, applications such as expert systems and ma-chine translation systems have been put to practicaluse one after another. A system in which problems aresolved with using a human rule of thumb (knowledge)is referred to as a knowledge based system.

Various development support systems and tools forknowledge base systems have been already introduced.In the industrial field, centering on expert systems, the

range of applications is rapidly broadening.In sewerage facilities, neural network systems are

actually employed in the inflow prediction system.These systems use personal computers and modify thesetting values of various parameters based on thedeviation between predicted inflow values and actualmeasured values. The computers ultimately learnfrom data to minimize the deviation between predictedand measured values.

5. Conclusion

In addition to the original purpose of sewagetreatment, sewerage facilities are deeply concernedwith community developments such as advanced infor-mation networks. It is believed that these networkswill to continue to advance in the future. Therefore,Fuji Electric will not fall behind and will also contrib-ute to social development.


Yasuhiko SonomuraMasami HasegawaShinyuu Kamino

Information Processing System forWater and Sewage Treatment Plants

1. Introduction

The trend of recent information processing systemsin water treatment plants is toward the enhancedrequirements of reduced construction, maintenanceand managing costs, together with requirements ofhigh functionality, following the rapid progress andimprovement of electronics and information processingtechnologies.

To respond these requirements, Fuji Electric real-ized an open architecture information processing sys-tem, employing the latest technologies as well astechnologies and expertise that have been cultivatedover many years, based on open architecture. In thispaper, we will introduce this latest information pro-cessing system.

2. Latest Information Processing System forWater Treatment Plants

2.1 Realization of medium to small-scale systems2.1.1 SCADA

Fuji Electric has developed FOCUS (Fuji opencontrol universal system) as a SCADA (supervisorycontrol and data acquisition) system. This system canrealize a low cost, highly functional control system byapplying expertise of the dedicated DCS (distributedcontrol system) system cultivated by Fuji Electric up tothe present. The system is configured with an operatorstation (FOCUS) and controllers. Low cost construc-tion of an open integrated control system is possibleusing an Ethernet*1 as a LAN to connect the twosystems.(1) System specifications

(a) Hardware specificationsPC/AT*2 compatible personal computers can beused in all operator stations. Windows NT 4.0*3 isused as the OS and InTouch*4 is employed as thefundamental part of the HCI (human-computer

interface). An Ethernet is utilized as the LAN forcontrol, but PE/P-LINK (enhanced processor/pro-cessor link) made by Fuji Electric can be also used.The following controllers made by Fuji Electricmay be connected: ACS (advanced controller) -2000, ACS-250, MICREX-F and MICREX-SX.Commercially available devices such as networkprinters for the printing logging panel, color ink-jetprinters for the copying panel and magneto-opticaldisks for data banking can be used as peripheraldevices of the FOCUS (personal computer). In thismanner, a low priced system can be constructed.(b) Software specificationsFor the FOCUS, a standard panel shown in Table 1

*1 Ethenet : A trademark of Xerox Corporation

*2 PC/AT : A trademark of IBM Corporation

*3 Windows NT 4.0 : A trademark of Microsoft Corporation

*4 InTouch : A trademark of Wonderware

Process input

Process value 576 points

Integrated value Including the above points

Digital 10,240 points

Setup valueProcess output

128 points

Operation 512 points

Trend panel8 pens × 64 pages Storage period: 5 days/1 min collection

Plant panel Panel sheet: 100 sheets

Logging panel

Sheet: Daily report : 20 sheets Monthly report: 20 sheets Annual report : 20 sheetsStorage period: Daily report : 62 days Monthly report: 12 months Annual report : 5 years

Computation expression Within the limits of Excel

Group loop panel Displays by grouped instrument modules

Alarm panelDisplays alarms in time series20 points/panel, 100 panels

Historical message panelDisplays historical messages in time series20 points/panel, 100 panels

System condition panel Displays system condition

Restriction of signal points: All using Tag= within 44,000 Tags AI per point = using 50 Tags Others per point = using 1 Tag

Remarks

Table 1 Standard panel specifications

Information Processing System for Water and Sewage Treatment Plants 131

is provided. Each panel is made with InTouch andhas an excellent operability due to ample incorpo-ration of Fuji Electric’s water treatment technolo-gies.For engineering support, a plant panel, central tothe monitoring operation, can be easily made intovisual panel using InTouch. Further, the loggingpanel format is designed with Excel*5. Therefore,the engineering of the FOCUS is an easy-to-usemonitor, able to realize EUC (end user computing).

(2) Examples of FOCUS system applicationsSeveral examples configurations will be indicated

below.(a) Remote monitoringIn addition to stand-alone use, the FOCUS canperform remote monitoring utilizing the merits ofan Ethernet. This system configuration is shownin Fig. 1.Routers are provided for the control LANs of localcontrollers. These LANs are constructed from anEthernet. Routers and the FOCUS are connectedto the network on the remote side (such as anoffice). This configuration makes the remoteFOCUS able to perform the same operation as the

local FOCUS.(b) Remote maintenanceThe water and sewage treatment plant is animportant piece of lifeline equipment. When anobstruction occurs in this monitoring system, im-mediate measures are necessary. In such a case, ifdiagnosis, status investigation and software modi-fication of the system are possible from the remoteside (such as a manufacturer’s office), the restora-tion time can be shortened. In the FOCUS system,collection of RAS information, straightforward cor-rection or modification of the software and investi-gation of defects can be performed via a telephoneline from a remote station.(c) Wireless LAN systemWhen utilizing FOCUS and a wireless LAN, it ispossible to use most FOCUS functions with note-book type personal computers from a remoteposition or freely moving, instead of from fixedCRTs. In this manner, one can visually monitor aplant, into which monitoring CRTs cannot beintroduced because of cost or the installationlocation, by carrying a notebook type personalcomputer with him. An example system configura-tion is shown in Fig. 2. The device is configured bysimply attaching an antenna to the notebook type

Fig.1 Remote monitoring system

*5 Excel: A trademark of Microsoft Corporation

To public linesFOCUS-PServer for remote

monitoring

Ethernet(coaxial cable)Announcement

printer

Ethernet(coaxial cable)

ACS-250

ACS-250ACS-250

Logging printer(Future)

Router

DSU

HUB

Repeater RepeaterOpticalcable

Ethernet(coaxial cable)

Router

Water purification plant (B)

Public lines

Converter

TransceiverNTT DA64digital access line

Public lines

Remote maintenance structure

Router

Ethernet (coaxial cable)

To public lines

Logging printer

FOCUS-P

FOCUS-P

Office A

Office B

To network

To network

Modembuilt-in

Maintenancecompany

Note PC withbuilt-in modem for remote main-tenance

Modembuilt-in

Announcement printerHard copy

FOCUS-P

HUB

DSU

Water purification plant (A)


Fig.2 Wireless LAN system

personal computer and providing onsite accesspoints.

2.1.2 Small-scale wide-area monitoring systemThis centralized monitoring system is for a medi-

um to small-scale town to improve the efficiency ofmaintenance and management (Fig. 3). This systemuses a general-purpose personal computer and a publicline (including use of a portable telephone) instead of adedicated line, and has a low price, regarded asimportant by the management.

A central monitor collects data from each facility ata fixed period or an arbitrary dial-up time. The data isused as panel, trend and logging data.

When an abnormality occurs in any facility, anemergency report is issued to emergency report devices(telephone, paging, etc.) and the central monitor.

2.2 System for large to medium-fieldsThis system is constructed with a standardized

architecture so that it can be applied to all systemsfrom large to small-scale. This system achievesflexibility and low cost in response to the requirementsof operation in a plant and yearly systematic construc-tion.2.2.1 Development concept

As a general trend in information and controlsystem, rapid advances are being made in systematiza-tion technology closely related to network systems suchas field dispersion, autonomy dispersion and openarchitecture systems.

This system, based on the above-mentioned trend,is developed to incorporate general-purpose technolo-gies such as the personal computer and the Ethernet,aiming to improve maintainability and to achieve highfunctionality, high performance and high reliabilitycorresponding to the open architecture.

This system enables configuration of systems thatconform to the present state and in which the combina-tion of old and new systems is becoming commonplace.This system is planned as a successor to the resources(hardware and software) constructed for the MICREX-IX integrated control system released in 1992.

The introduction of new technologies, compliancewith an open architecture environment, enrichment ofthe service environment, and flexible response to userrequirements, and guarantee of reliability are alsoplanned for this system.2.2.2 System requisites

When constructing an advanced open process auto-mation system, it is necessary to maintain the pasthigh reliability and real-time performance and further,to employ an open architecture, an important conceptfor information control. Requisites for the advancedopen process automation system will be describedbelow.(1) Open architecture of data

The process data, operation and history data andtrend data stored in the information processing systemshould be able to be freely exported to a personalcomputer connected to the network, and be used forsuch applications as the creation of statistic materials,evaluation of maintenance and management, develop-ment of operation plans, etc,(2) Realization of end user computing

Through offering a support system that utilizes aneasy to understand, personal-computer-like graphicaluser interface and ISV (independent software vender)software, the system should be able to be improved ormodified by the user himself.(3) Freedom and cost reduction

In the past manufacturer’s standard, DCS (distrib-uted control system), the user’s freedom of selectionwas restricted to some extent to realize high reliabilityand comfortable operability.

P-Link *2

*1: Ethernet*2: P-Link: LAN for control (made by Fuji Electric)*3: Wireless LAN specification ™Frequency: 2.4 GHz band ™System: Direct spectrum diffusion system ™Speed : 2 Mbps ™Distance: 30 to 50m indoor

Ethernet *1

HUB

Motor roomElectrical room

Wireless point

Wireless point

PLC panel

WirelessLAN card

Indicationterminal

Wireless point

Wirelesspoint

Controller forinstrumentationpanel

Monitoringinstrumentationpanel

Machinery roomOperation room

Fig.3 Small-scale system

Same ason left

Pumpingstation D

Same ason left

Pumpingstation C

(4 to 20mA)AiDi

Modem

Water purification plant B

Public lines

LAN forcontrol

PLC FAXTelephone PagingCentral monitor

Main water purification plant (Water purification plant A)


Fig.4 System for large to medium field

speed and function, coexistence of the plant controlwith the production control is a big problem.

In response to this problem, an operation environ-ment is realized in which there is a link functionbetween the process data and management data byemploying an Ethernet, an open network, as the LANfor control in this system.

In addition, an SQL server is mounted on thedatabase to provide open data so that the user canutilize the plant data freely and easily. The storeddata can be edited and modified by using a commer-cially available spreadsheet program or database soft-ware.

Moreover, the user can utilize the same functionsas in a HCI device through a general-purpose LANfrom an AOS (advanced operator station) -PC (personalcomputer) for HCI use located at an arbitrary site.

This system is an open information processingsystem, is a successor to the high reliability and highperformance of DCS, and will comply with futurenetworks.(2) Excellent reliability and maintainability

This system realizes high reliability and maintain-ability with an advanced self-diagnostic function andRAS information based on the technologies cultivatedin the IX series for custom devices.

To achieve the required reliability of the operationsystem, duplex design for an Ethernet that uses anyinformation, control or onsite LANs is made possible inaddition to the conventional duplex system for thedevices.

To achieve the required maintainability of thesupport system, it is possible to read the various typesof RAS information and write programs from an AES

*: AX: Advanced information and control system for the next generation

IPU(Intelligent Process input-output Unit)

Remote PIO

Field LAN Ethernet (10/100Mbps)

T-LINK

AX* controllers max. 30 sets[Unit type]ACS-2000

[Unit type]ACS-2000

ACS-250

Control LAN

Ethernet duplex design (10/100Mbps)

AOS-PC2000max. 16 sets

ADS-PC20002 servers provided (personal computers)

AOS-PC2000 AOS-PC2000 AES

Public linesInformation LAN

Ethernet (10/100Mbps) Ethernet (10/100Mbps)

General-purposepersonal computerNetwork printer max. 8 setsAOS-PC2000 AES Remote AOS-PC

Coupled with the adoption of an open architecture,utilization of de facto standards eliminates dependenceupon manufacturer standards and results in demandfor systems with a high degree of freedom, anddownsizing results in cost reductions.(4) Fusing of control and information

Due to the open architecture of the database, theuser should be able to effectively utilize stored data,which could not be sufficiently utilized in the past.Further, the data should be able to be used in a high-level information and control package, and in thesystems of business management, work management,utilization and opening of information, equipmentmaintenance, etc.(5) Realization of general-purpose hardware

The system should be constructed using the latestdevices on the market as components.2.2.3 System configuration and features

The system configuration is shown in Fig. 4.This system realizes an information system con-

sisting of: operator stations, open database stations,high-speed control LANs, high-speed control stationsand intelligent field centers. Furthermore, the configu-ration of this system integrates functionality through ahigh-speed LAN with operation control systems, worksupport service systems, multi-media communicationsystems and computer network systems, providingsolutions to the aforementioned requisites.(1) Open architecture

With the integration of monitoring and control, itis inevitable that demand increases for system integra-tion with a production control system. However, sincethere is a large difference between plant control andproduction control from the viewpoint of processing


(advanced engineering station) that is remotely locatedand connected to information and control LANs. Coex-istence of AES and AOS functions in the same personalcomputer provide the benefit that a manager in officeor a maintenance person in a maintenance room canobtain RAS information in addition to monitoring theoperation state.2.2.4 Overview of the system(1) Control LAN function

This system utilizes an Ethernet, a practical defacto standard in the OA field, and at this time, newlyemploys an FL-Net compatible protocol, recognized byJEMA as JPCN-2, allowing easy connections withproducts made by other manufacturers, while main-taining the real-time characteristic of data. In thepast, this characteristic was considered difficult tomaintain.

With this protocol, cyclic transmission, the trans-mission of information within a definite time, andmessage transmission, the transmission of manage-ment information and schedule information, are real-ized.

The FL-Net compatible protocol uses UDP/IP, astandard Internet protocol, as a basic part, andemploys a token function, to avoid the collision ofinformation and guarantee the reliability and real-time characteristic.(2) HCI function

This innovative system can display panels identi-cal to those of the HCI of the plant via public lines(ISDN, frame relay, etc.) from the remote-side general-purpose PC and the combination of an AOS-PC2000(personal computer), an HCI using open architecturematerial, and commercially available general-purposesoftware. Further, a remote control monitoring systemvisible through a browser can be realized.

Moreover, in the operator station, the system canmonitor camera images of a local patrol terminal.Onsite images can be monitored and controlled usingremote connections, mobile computing and wirelesstechnology.

The visibility of HCI itself is improved by increas-ing the number of colors and enabling color expressionfor the targeted plant. Operability is also improved bythe Windows-like panel configuration, panel develop-ment, three-dimensional appearance of operationswitch buttons, etc.

Either “mouse” or “touch” can be selected as thepointing device. Figure 5 shows examples of the panel.(3) Data base function

Connection with general-purpose databaseIn business reporting by the user, instances of

report generation based on operation data and controldata are increasing.

Therefore, it is desired that the user himself caneasily extract the operation data and control data, andthen edit the data with general-purpose software.

In the ADS, connection with a general-purpose

Fig.5 Examples of panels

Fig.6 Database connection

(1) Picture made by dialog

(2) Trend panel

Control stationACS

Personal computer

General-purpose software (SQL client)Excel, Access, etc.

™Operation control

™Quality contnrol

™Maintenance

General-purpose database (SQL server) ™Trend data ™Historical alarm data ™Historical running

data ™Daily, monthly and

annual report data

Specific database

™Trend data ™Historical alarm data ™Historical running

data ™Daily, monthly and

annual report data

General-purposedatabase connection

Database stationADS

Ethernet

Operator stationAOS

*6 Windows SQL : A trademark of Microsoft Corporation

*7 Access : A trademark of Microsoft Corporation

database is possible (Fig. 6). The general-purposedatabase is equipped with a Windows SQL*6 Server ofthe Microsoft Corporation. The trend, logging, alarmand operation history data managed by the ADS(advanced database station) has been stored in thegeneral-purpose database. The user is offered anenvironment where he can freely manipulate this datausing general-purpose software such as Excel andAccess*7 through an Ethernet line on the persona


Fig.8 Advanced control system

pH meter

pH meter

M (Indoor)

Coagulation controller

Optical sensorunit

Converter unit

Coagulation sensor [Example]Computer systemWorkstationDCS systemRecorder

Information processing

[Related system] [Basic system]Coagulation control in water purification plant

Rapid mixing tank

Chemical feed rateRaw water flow rate

Set up value of feed ratio / feed rate

Chemical feedsystem(feed control)

DDC Single loop controller

Measuring system

InstrumentsRecorders,indicators

™The mean particle sizeof floc

™Mixing tank pH™Coagulant feed ratio setup

value™Alkali feed ratio setup value

Mixing tank pH

Calculation andcontrol unit

The mean particlesize of floc

Chemical feed rate

Raw water flow rate

Coagulant feed ratio setup value Alkali feed ratio setup value

Fig.7 Configuration of intelligent field center system

I/O

I/O

I/O

I/O

<Local panel> <Local panel>

<Field LAN (Profibus)>

IFC: Intelligent Field Center

<Control center>

<ACS-2000>

Control LAN

Information processing system

computer of a client.(4) Controller function

For process control devices, open architecture andinformation-orientation are promoted by upgradingconventional technologies. New devices such as anintelligent field center and local handy terminals areprovided.

Durable PC boards (PCU), which employ statictype RAM disks having no moving parts can bemounted on the ACS-2000 controller. In this manner,advanced control (analysis and forecast calculation),conventionally required of workstations, can be com-puted on devices in the local field. This functionality

can be realized on distributed controllers in the localfield by improving the calculation speed and real-timecharacteristics. Further, the product series isstrengthened with regards to telemeter and telecontrolfunctions.

(a) Intelligent field center (IFC)The intelligent field center (Fig. 7) realizes onsiteLAN (Profibus*8) transmission of all signals byintegrating the conventional functions of controlcenters and auxiliary relay panels into a dedicatedelectronic control unit.The control unit is equipped with a protectionfunction, and memory functions of fault electricalcurrent and operation history. Facilitating thecollection of RAS information makes it possible toshorten the MTTR (mean time to repair).The employment of an onsite LAN (Profibus)facilitates cable cost reduction, wiring work ratio-nalization and the addition of devices, as well asmaking possible the integration of managementand control information, reduction of maintenancecost, promotion of sensor intelligence and construc-tion of an inter-operable multi-vender system.(b) Coagulation control system (advanced control)It was confirmed by various experiments that thecoagulation and sedimentation processes in a wa-ter purification plant depend on the size of parti-cles in coagulation flocs. An advanced coagulantfeed system (Fig. 8) combining a device to measurethe coagulation flocs in real-time (coagulationsensor) with a model forecasting control device(coagulation controller) has been developed.Conventionally, due to chemical feed ratio control

*8 Profibus: A trademark of Siemens A.G.


Since the master station can be connected via a T-Link (terminal link) to sequencers of the companyand other controllers, flexible configurations arepossible.

(5) Process I/O functionsIn addition to the conventional IPU (intelligent

process input-output unit), an open architecture PIO(process input-output control unit) is employed in thesystem.

The open architecture PIO*9, a remote processinput-output device developed under the basic princi-ple of “small and high-reliable open architecture PIO”,is connected to a 10 Mbps or 100 Mbps Ethernet.

Features of the open architecture PIO are listedbelow.

(a) Remote process input-output device connectedwith an open architecture IO bus

The I/O bus that connects process input-outputdevices is an Ethernet that is an open architectureLAN. The interface technology is open so thatcontrollers from other companies in addition tothose from Fuji Electric may be connected.(b) Process input-output device equipped with fea-

tures for the PAS (process automation system)market

This process input-output device is equipped withfeatures for the PAS market such as a RASfunction, redundancy function and resistance tothe environment.(c) Process input-output device conforming to in-

ternational standardsThis process input-output device conforms to inter-national standards such as safety standards, CEmarking specifications and intrinsic safety stan-dards, adapting to the worldwide market.

3. Conclusion

In this paper, we have introduced the latestinformation processing system for water and sewagetreatment plants.

In the future, we will offer products and servicesfor system lifecycle management, from daily mainte-nance through renovation, for the safe operation of thissystem.

based on raw water turbidity (feedforward control)or chemical feed control based on operator’s experi-ence, too much coagulant has often been injected.However, due to feedback control based on the flocparticle sizes, the coagulant came to be adequatelyinjected.In this control, since parameters must be adjusteddepending on the characteristics of each mixingtank and water, it is necessary to gather data for afixed period after introduction. However, this dataanalysis and parameter setting can be easilyperformed with support tools and engineeringsupport.(c) Telemeter and telecontrolASA (advanced supervisory and data acquisition)-2000 is a TM/TC (telemetry and control equip-ment) device that can be connected through adedicated line on the voice call band to multiplelarge-capacity slave stations.Connection between a master station and othercontrollers or HCI devices is possible with acompany specific LAN (DPCS (distributed processcommunication system) -F and P/PE-LINK) and anEthernet (compatible with FL-Net), making flexi-ble configurations possible.The master station can be connected with slavestations of various scales and functions such as theSAS (supervisory and data acquisition system) -50in addition to the ASA-2000.The slave stations can be constructed as multi-function devices by attaching not only a transmis-sion function but also various sequence functions.The transmission system can perform high-speed(maximum 9,600 bps) and highly reliable transmis-sion by employing the HDLC (high-level data linkcontrol procedure) transmission method in additionto the CDT (cyclic digital telemeter) transmissionmethod (cyclic transmission method).The SAS-15 is a 1:1 type, compact-size and highlyexpandable TM/TC device that transmits over adedicated line on the voice call band. Since thecapacity and layout are fixed, such software as alayout table is unnecessary.

*9 Incollaboration with Yokogawa Electric Corporationand Fuji Electric

Advanced Water Treatment Technology for Waterworks and Sewerage Systems 137

Kazutaka TakahashiNorimasa NonakaRyutaro TakahashiNobuyuki MotoyamaKousei Sasaki

Advanced Water Treatment Technologyfor Waterworks and Sewerage Systems

1. Introduction

One hundred years have elapsed since modernwaterworks made their debut in Japan. Over thisperiod, the saturation level of waterworks has exceed-ed 93% and Japan has literally entered an “era of highsaturation.” However, due to the progress of industrialactivities and concentration of the population in cities,various types of effluent flowing into the public waterarea has increased, and the offensive taste and odor ofthe tap water has become problematic. Further, it hasbecome evident that various micro-organic pollutantsand chlorinated materials exist in rivers, and theexistence of trihalomethanes (THMs) in tap water hasalso become evident. Therefore, measures must beimplemented in waterworks from a new viewpoint.

The recent deterioration of the water environmentis becoming increasingly serious and the water envi-ronment is undergoing many various changes, regard-less of artificial or spontaneous reasons such as micro-pollutants, such as pesticides and neutral detergents,eutrophication and the generation of pathogenic organ-isms.

In the future, the introduction of treatment andmonitoring systems for pathogenic organisms, pesti-cides and micro-organic substances will be necessary,and especially, the regulation of disinfection byprod-ucts is anticipated to become stricter.

It is expected that these treatment systems andmeasuring and monitoring system for micro-chemicalsubstances will be developed in the future.

As for the trend of sewerage systems, the satura-tion level has exceeded 50% and their role is diversify-ing, as these systems are becoming an importantinfrastructure for daily life.

In the past, the role of sewerage systems was tocollect and treat the wastewater discharged from thecity and to remove the wastewater from our livingarea. Recently, however, treated sewage effluent hasbecome an important water resource in the city.

Reflecting that status, disinfection of the treatedsewage effluent requires a severity of methods. Forexample, when the treated sewage effluent is dis-charged into a clear stream where sweetfish are

swimming and many sorts of aquatic life are living,chlorination is not suitable because of its residualproperty and influence upon the ecology. Disinfectionusing ozone or ultraviolet radiation is required becauseits non-residual property. Therefore, at the Hirose-river purification center in Sendai-city, ozone disinfec-tion was employed. Further, when reusing treatedwater, the necessary disinfection level differs depend-ing on the use, and disinfection technologies shall beinvestigated in consideration of water quality itemsthat provide a person with comfort such as transparen-cy.

In the past, the purification process utilized con-ventional treatments to guarantee tap water in con-formance with tap water quality standards. Now,however, due to the state of water pollution in waterresources, it is becoming necessary to maintain thewater quality of raw water itself for tap water.

In this paper, the latest advanced water treatmenttechnology for waterworks and sewerage will be intro-duced.

2. Advanced Water Treatment Technology forWaterworks and Sewerage

2.1 Current practices of advanced water treatment2.1.1 Advanced water purification in waterworks

This treatment technology is used to treat odoroussubstances, trihalomethane forming precursors (THM-FP), trihalomethanes, color, ammonium nitrogen, an-ionic detergents, etc. which cannot be removed byconventional potable water treatments (coagulation-settling, slow filtration, rapid filtration and chlorina-tion). This treatment technology is being applied inaddition to the conventional treatment.

Advanced treatments are roughly classified intothe following three treatments (Fig. 1), and whennecessary, are applied in combination in addition toindependent application. In particular, ozonation iseffectively applied together with activated carbon inmany cases.(1) Effects of ozonation

Ozonation is a treatment that uses the muchstronger oxidation of ozone instead of that of chlorine.


The function and main usage effects of ozonation areas follows:

(a) Odor destruction : Odor and taste removal(b) Removal of trihalomethanes and trihalom-

ethane forming precursors(c) Removal of color(d) Conversion into smaller organic molecules :

Improving adsorption of activated carbon(e) Generation of biodegradable organic matter :

Improving treatment of biological activatedcarbon (BAC)

(f) Removal of pesticides etc.(g) Oxidation of iron and manganese(h) Inactivation of virus

(2) Effects of biological treatmentBiological treatment is used to obtain the effect of

treatment from a biochemical reaction created byorganisms existing on a biofilm. There are two typesof biological treatments, anaerobic and aerobic, but theaerobic treatment is normally used in the waterworks.

Biological treatment is effective on ammoniumnitrogen, algae, moldy odors, anionic detergents, man-ganese, etc., and removes turbidity. Biological treat-ment reduces the color, KMnO4 consumption, etc., butthe potential for forming halogenated organic matter ishardly removed if the precursor is soluble.(3) Effects of activated carbon

There are three advanced treatments: ozonation,activated carbon and biological treatment. However, ifozonation and activated carbon are used together,odors are almost perfectly removed, and the life of theactivated carbon is prolonged because the burden hasbeen shared between ozonation and activated carbon.

Among the activated carbon treatments, there is aso-called biological activated carbon (BAC) treatment.This treatment is a system in which microorganismsare attached on the surface of granular activatedcarbon, and both physical adsorption of the activatedcarbon and biological treatment by microorganisms aresimultaneously performed. As mentioned above, inthis case, the life of the activated carbon increases bythree times or more compared to the normal case.

Ozonation at the previous stage of the biologicalactivated carbon treatment is effective in improvingbiological treatments. Ozonation and biological acti-

Table 1 Principal sewage advanced treatments and functionsfor the purpose of water reuse

◎: Better ○: Effective △: Less ―: None

Water quality item

SS

Turbidity

Color

Odor

BOD

COD

Detergent

T-P

T-N

NH3-N

E.-coli

Dissolved inorganic substances

◎

◎

―

―

○

△

―

―

―

―

△

―

―

△

○

◎

△

○

○

―

―

―

―

―

―

△

◎

◎

△

△

○

―

―

―

◎

―

◎

○

△

△

○

△

△

―

―

○

○

―

Sand filtration

Activatedcarbon filtration

Ozone Biofiltr-ation

Fig.1 Advanced potable water treatment

Advanced treatment

OzonationPowdered activatedcarbonActivated

carbon Granular activatedcarbon (GAC)

Fluidized bedAdvancedtreatment

Fixed bed

Honeycomb Bacterialactivatedcarbon(BAC)

Biologicaltreatment(Contact aeration)

Rotary disc

vated carbon treatment are generally applied in combi-nation. The effects of combined ozonation and biologi-cal activated carbon treatment is as follows:

(a) The burden of the treatment can be shared.(b) The combination has a wide-ranging treatment

effect.(c) By combining the biological activated carbon

treatment at the next stage of the ozonation,byproducts formed by ozonation are removed.

Bio-refractory organic substances are decomposedinto biodegradable substances in ozonation, and theseare biologically removed in the biological activatedcarbon treatment tank.2.1.2 Advanced water purification in sewerage

Advanced water purification is a general term forhigher-level treatment technologies whose aim is re-use, environment protection, or the removal of sub-stances that cannot be removed by conventional sec-ondary treatments. The treatments are classifiedmainly into the removal of organic substances andremoval of nutrients.

The following technology exists for advanced treat-ments in sewerage:(1) Removal of organic substances

Coagulation and sedimentation, sand filtration,activated carbon filtration, ozonation, biological fixedbed, ultra-filtration and reverse osmosis(2) Removal of nutrients

Coagulation and sedimentation, crystalization de-phosphatation, break point chlorination, ion-exchange,activated sludge with coagulant, phospho-stripping,anaerbic-aerobic activated sludge, biological denitrifi-cation, oxidation ditch, batch-type activated sludge andreverse osmosis

From amongst these technologies, ozonation isespecially excellent in removing colors and odors,disinfecting reused water, and in eradicating the ozone


by self-decomposition so as not to influence the envi-ronment, differing from the residual of chlorination(Table 1).

2.2 Innovative advanced water treatment2.2.1 Disinfection technology for Cryptosporidium

parvum oocysts by ozoneIn recent years, water-born group infection by

Cryptosporidium parvum oocysts has become a severesocial problem.

Cryptosporidium parvum is a parasitic protozoa,and only approximately 3log10 of the infectious type ofoocysts could be removed with conventional rapidfiltration. Further, chlorination as a disinfectant inthe waterworks hardly has any disinfecting effect.Moreover, the infective doses for human are so smallthat a 50% infective dose is 132 oocysts and a 1%infective dose is 2.4 oocysts. Therefore, this hasbecome a very serious problem to guarantee waterquality for sanitary tap water. To inactivate theCryptosporidium parvum oocysts, treatment withozone seems promising and the CT values of 2log10

inactivation are 3.5 to 17mg · min/L estimated with theanimal infection method and 12 to 16mg · min/L esti-mated with excystation. However, because of differentexperiment conditions and estimation methods, the CTvalues are greatly discrepant. Therefore, it is neces-sary to gather even more knowledge for defining thelevel of ozonation in water treatment.

Recent research on the ozonation disinfection ofCryptosporidium parvum oocysts conducted by theauthors will be reported below.(1) Influence of residual ozone

When testing under the conditions of pH 7, watertemperature of 20°C and residual ozone of 0.05 to0.5mg /L using excystation and the DAPI/PI stainingtest, the results showed that the influence of residualozone was small and that the inactivation effect couldbe expressed with simple CT values. The inactivationCT values of 1 and 2log10 were 6.3 to 7.6 and 10 to12mg · min/L with excystation and 7.5 to 12 and 16 to24mg · min/L with the DAPI/PI staining test. Further,the inactivation curve by ozone could be expressedwith a series event model, and could be approximatedwith a two-hit model for estimation by excystation andwith a one-hit model for estimation by the DAPI/PIstaining test.

Using the mouse infection method, tests wereconducted under the conditions of pH 7, water temper-ature of 20°C and residual ozone of 0.3 and 0.5mg /L.To estimate the infection, a Cryptosporidium parvumoocysts suspension after ozonation was centrifuged andwashed 3 times, diluted step-by-step with 5 successivedilution series, and given to 5 scid mice (6 weeks ofage) by oral-injection at every dilution step. After 4weeks from the oral-injection, the oocysts in feces wereexamined, and an MPN (maximum probable number)was calculated. Defining ID (infective dose) as 1 MPN,

and IF (infective factor) as the reciprocal of ID(infective dose), the relativity of the infective factorwas estimated with IF/IF0 (ID0 /ID). As the result, the2log10 inactivated CT values are approximately 3 and6mg · min/L at residual ozone levels of 0.3 and 0.5mg/Lrespectively, and the lower the residual ozone is, thesmaller the CT value. The 2log10 inactivated CT valuesreported by Finch, et al. were 1.7 and 2.6mg · min/L atresidual ozone levels of 0.25 and 0.5mg /L respectively,showing a similar tendency. From these results,inactivation by estimation of infection could possibilitybe dependent upon the residual ozone. The cause ofthe difference between our research and Finch’s re-search must be investigated, but, judging both resultscomprehensively, the 2log10 inactivated CT value byestimation of infection is considered to be 6mg · min/Lat the maximum.(2) Influence of pH

In the excystation test, an experiment was con-ducted under the conditions of water temperature of20°C, residual ozone levels of 0.1, 0.3 and 0.5mg/L andpH 6, 7, 8 and 9. The 1log10 inactivated CT valueswere scattered about 5.5 to 9.0mg · min/L at theresidual ozone level of 0.5mg/L, but were 6.3 to7.6mg · min/L at the residual ozone level of 0.1mg/Land 6.7 to 6.9mg · min/L at the residual ozone level of0.3mg/L, and no large difference existed. From theseresults, it is considered that the influence of pH doesnot exist under the condition of constant residualozone.(3) Others

Methodology has been investigated to estimate theinactivation level of animal infection with alternativemethods such as excystation, DAPI/PI staining, etc.,but these methods have not yet been sufficientlyestablished. With the exception of specific organiza-tions, there are many difficulties in introducing anestimation method by animal infection. From theviewpoint of the actual circumstances of the water-works and sewerage fields in Japan, progress inresearch into the relation between both animal infec-tion and alternative methods is desired.2.2.2 Control of bromate ion formation

Bromate contamination, based on the guidelinevalue of 25 µg/L in the WHO drinking water qualityguideline (1993), has been determined to be a carcino-gen, and in addition, the maximum contaminant level(MCL) of 10 µg/L was indicated by USEPA last year.These values are open to further discussion, but whenraw water includes a high concentration of bromide iondue to the influence of sea water flowing against thestream, there exists a possibility that bromate ionexceeding these values is formed by ozonation.

To control this bromate ion, various research hasbeen implemented. As an example, if the main goal ofozonation is to control trihalomethane formation, ithas become clear that bromate ion formation can becontrolled with the following method.


Bromate forming characteristics from the batchtest shown in Fig. 2 indicate that ozone first reactswith the THM forming precursor followed by anincrease of residual ozone in the treated water, andthen the bromate ion is formed. From these character-istics, if residual ozone control is used for ozone dosagecontrol and the residual ozone is controlled to approxi-mately 0.1 to 0.2mg/L at the point where the residualozone is a maximum, it is understood that the bromateion formation will be restricted and sufficient removalof the THM formation ability will be obtained.2.2.3 Advanced water treatment with ozone resistant MF

membraneApplication has begun of micro-filtration (MF)

membranes and ultra-filtration (UF) membranes towater purification, and these have been introducedinto and are operating in more than one hundred smallplants. In Europe and America, membrane filtrationfacilities have been already operating in purificationplants of the several ten-thousands tons/day scale. InJapan, as a response to problems such as Cryptospo-ridium, it is considered that in the future, purificationfacilities using micro-filtration membranes and ultra-filtration membranes will be introduced into larger-scale purification plants.

On the other hand, due to the contamination of

water resources, many purification plants are consider-ing the introduction of advanced treatment facilitiesusing ozone and biological activated carbon. In theadvanced treatment MAC 21 project, a hybrid treat-ment of membranes and advanced treatment was alsoconsidered. However, when using organic membranes,deterioration of the membrane material became prob-lematic, and therefore, the combination methods werelimited. As a solution, a micro-filtration membraneusing PVDF resistant to dissolved ozone as membranematerial has been developed, enabling a more effectivecombination of membranes and advanced treatment(Fig. 3).(1) Ozone resistant membrane module characteristic

Type of membrane : Outer skin hollow fiberMembrane material : PVDF

(polyvinylidene fluoride)Nominal pore size : 0.1 µmMembrane area : 50 m2

(2) Membrane treatment and effects with ozone resis-tant membrane

Presently, the membrane filtration equipment ap-proved for water supply is the equipment that usesmicro-filtration membranes and ultra-filtration mem-branes, and treats turbidity and disease-causing germssuch as bacteria, Giardia and Cryptospordium. Con-ventional coagulation/sedimentation/filtration and mem-brane filtration basically treat the same substances.However, conventional technology treats water qualityin mg/L orders, but in principle, membrane filtrationperfectly removes particles larger than the pore size ofthe membrane. Since Cryptospordium has the possi-bility to cause disease even when there are severaloocysts in 1 m3 of water, conventional treatments maybe difficult for operation and control. On the otherhand, conventional treatments may surpass membranefiltration in such water quality criteria as colorcomponents.

Membrane filtration has the feature of perfectremoval of impurities larger than the pore size asshown in Fig. 4, and in addition, the use of coagulant iszero or very small and the area for the facility can bereduced. However, membrane filtration must becombined with advanced treatments such as activatedcarbon adsorption for substances such as odorous

Fig.2 THMFP removal and bromate ion formation by ozonation

Ozone consumption (g/m3)

40 0.4

35 0.35

30 0.3

25 0.25

20 0.2

15 0.15

10 0.1

5 0.05

00.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

0

THMFP removal rate (%)

Bromate ionconcentration(µg/L)

Residual ozoneconcentration(g/Nm3)

Res

idu

al o

zon

e co

nce

ntr

atio

n (

g/N

m3)

TH

MF

P r

emov

al r

ate

(%)

Bro

mat

e io

n c

once

ntr

atio

n (

µg/L

)

Bromide ion concentration in raw water: 520 µg/L

Fig.3 Schematic diagram of advanced water treatment system

P

P

P

Ozone-resistantmembranemodule

BackwashwasteScrubbingwaste Permeate

tankRawwater

Feedwatertank

Backwashpump

Feedpump

Backwashwaste

Storage PumpRawwatertank

Pre-filter Ozonator

Compressor

tank

Activatedcarbon filter

Fig.4 Particle size and separation method

Reverse osmosis

Nano-filtration

Ultra-filtration

Micro-filtration

Activated carbon adsorptionCoagulation-filtration

Size

Odorousmaterials,NH4-N

Pesticides,Fulvicacid

HumicacidClayBacteria

10µm 1µm 0.1µm

Virus

0.01µm 1nm 1

ParticleSilt,Algae


Fig.5 Anaerobic-anoxic-aerobic process control system

substances and pesticides that are difficult to removewith micro- or ultra-membrane filtration. Of thevarious combination methods, use of ozone resistantmembranes is considered as a method that limitsclogging and fouling of the membrane while utilizingthe feature of membrane filtration. Use of ozone as apre-treatment of membrane filtration promotes theinsolubility of metallic salts, coagulation of impuritiesin raw water, decomposition of sticky organic matters,and limits clogging and fouling of the membrane.Further, by keeping the dissolved ozone concentrationon the surface of the membrane, the multiplication oforganisms on the surface is prevented and organicsubstances adsorbed on the surface or inside of themembrane are decomposed. As a result, a high fluxcan be maintained. Currently, a high flux of 5m/dayper unit of transmembrane pressure, 4 to 5 timesgreater than the conventional membrane filtration forwaterworks, is obtained in water with ozone dosing of2mg/L. Moreover, the frequency of cleaning themembrane with chemicals is remarkably reduced,

Secondary settling™Return sludge

quantity flow control(Influent water

quantity index)™Excess sludge

quantity control(A-SRT control)

Aerobic tank™A-SRT control (Nitrification)™DO control (Nitrification)™Coagulant addition control

(Phosphate removal)(Influent water quantity index, Counter measures

against rain water)

Anoxic tank™Recirculating sludge

flow control(Denitrification)(Influent waterquantity index)

Influent water™Primary settling

bypass control(Phosphate removal)(Influent water

quantity index)

Maincontrolitems

Concentration meter

Excess sludgeReturn sludge

Raw sludge Air

Sandfiltration

SecondarysettlingAerobicAnaer-

obicAnoxic

Primarysettling

Flowmeter

Valve

Raw sewage Polishedeffluent

Flow meter

Flow meter

Flow meter Flow meter

Recirculating sludge

Waterlevel

T-N

T-PSettlingzone

Primary settlingbypass sewage

Pathchangeover

Temp. PH

MLSS DO

Methanol

ORP ORP

Coagulant

Coagulant additionMethanol addition

facilitating operation and maintenance control. As forthe water quality, good water treated with advancedtreatment is obtained by combining ozonation andactivated carbon.

3. Advanced Water Treatment for Sewerage

3.1 Nitrogen and phosphate removalAdvanced water treatment for sewerage and the

technology of Fuji Electric is shown in Table 2.Regarding nitrogen and phosphate removal, represen-tative of advanced treatment technologies, Fuji Elec-tric has accumulated many good results for processcontrol systems of the anaerobic-anoxic-aerobic method(A2O) and Modified Ludzack-Ettinger (MLE) processwith coagulant.

Figure 5 shows an overview of the process controlsystems of the anaerobic-anoxic-aerobic method. Ni-trogen removal consists of 2 stages of nitrification anddenitrification, and performs A-SRT control that con-trols the removal of excess sludge to stabilize thenitrification and the restoration of sludge to efficientlydenitrify, etc. Phosphate removal can perform primarysedimentation bypass control to maintain a high-levelof phosphate removals corresponding to variations inthe inflow water quality, coagulant adding control, etc.Highly reliable control is a feature of Fuji Electric’stechnology.

In addition to the above-mentioned controls, com-puter based technology is developing to simulate thebehavior of organisms in each reaction tank related tonitrogen or phosphate removal, and to predict thetreated water quality. It is believed that the introduc-tion of this simulation technology will lead to the

™Ozonation™Advanced oxidation process (AOP)

Advanced treatment Fuji Electric s technology

Nitrogen and phosphate removal

™A2O process control system™MLE nitrification-denitrification

process with coagulant control system™Dual tank type intermittent aeration™Dual tank type intermittent aeration

with membrane separation

Disinfection of treating water

™Ozone disinfection

Reuse of treated water

Table 2 Sewage advanced treatment and Fuji Electric’stechnology


Fig.6 Flow diagram of dual tank type intermittent aerationprocess with membrane separation

ThickenerExcess sludgeDehydration water

Returnsludge

Blower

Membraneunit

Aeration stirrer

Effluent

Controller

Secondreaction tank

Firstreaction tank

DO ORP

EqualizationtankInfluent

realization of greater stability in the operation ofadvanced treatment processes.

Fuji Electric has independently developed a dualtank type intermittent aeration process and dual tanktype intermittent aeration process with membraneseparation as advanced treatment processes for small-

Fig.7 Flow diagram of activated sludge process withoutexcess sludge

Aeration tank Settling

Raw water BODEffluent

Return sludgeOzonated sludge

Ozonation tank Ozone generator

scale treatments. A flow diagram of the dual tank typeintermittent aeration process with membrane separa-tion, the most advanced treatment process, is shown inFig. 6. This process repeats aeration and stirring andcreates anaerobic-anoxic-aerobic conditions in a timeseries using the oxidation reduction potential (ORP) asa control index to remove nitrogen and phosphatesimultaneously in each reaction tank. Table 3 showsthe results of domestic sewage. The treated waterquality is very good as BOD and SS (suspended solids)are less than 1mg/L, T-N is 5mg/L and T-P is 0.1mg/L.In the future, these advanced treatments will bewidely introduced.

Fuji Electric has been actively dealing with theozonation of sewage and has accumulated much experi-ence with ozone disinfection that is harmless to theecology in the discharge area and suitable for the reuseof treated water.

3.2 Activated sludge process without excess sludgeActivated sludge process is widely used for waste-

water that includes organic substances. This is an

Table 3 Pilot plant treatment results for dual tank typeintermittent aeration with membrane separation

Item Influent water Treated water Removal ratio

BOD (mg/L)

COD (mg/L)

SS (mg/L)

T-N (mg/L)

T-P (mg/L)

181

93

120

42

4.5

<1

5.9

<1

5.0

0.1

99% or more

94%

99% or more

88%

97%

Table 4 Pilot plant test results

Item Treatment with additional ozone

Conventional treatment without ozone

Experimental conditions

Quantity of water treated (m3/day)Retention time in whole aeration tank (h)

Aerobic tank (h) Anaerobic tank (h)

MLSS concentration (mg/L)Sludge return ratio (%)Water recirculation ratio (%)

10241212

3,000 to 4,5003616

10241212

2,500 to 4,5003616

Water quality

Sludge

Ozone treatment sludge (m3/day)Ozone dosage

for treating sludge (kgO3/kg VSS)for treating water (mg/L)

0.36

0.0516

—

——

Raw water Treated water Treated water

T-BOD (mg/L)S-BOD (mg/L)T-COD (mg/L)S-COD (mg/L)SS (mg/L)T-N (mg/L)NH4-N (mg/L)NOx-N (mg/L)T-P (mg/L)PO4-N (mg/L)

11.61.720.014.219.67.10.13.42.31.6

19132.612228.324034.418.10.04.21.3

10.81.013.67.510.35.60.12.21.81.2

Excess sludge quantity (kg/day) 0 ca. 0.7


excellent process that utilizes organism functions, butthe multiplied organisms must be removed from thesystem as excess sludge and disposed of. In recentyears, because of the increase of sludge quantity andthe shortage of sludge disposal areas due to highersewerage saturation levels, it is strongly desired toreduce the excess sludge quantity. As a countermea-sure to this problem, a new activated sludge processhas been developed.

Figure 7 shows the basic flow diagram of theprocess. A constant quantity of activated sludge ispulled out through a return sludge line and returned toan aeration tank after treatment with ozone. Theprinciple of this process is that the activated sludge isconverted to organic matter able to biologically decom-pose due to the strong oxidation reaction of ozone in anozone reaction tank. This organic matter becomes food

for the activated sludge in the aeration tank anddecomposes into water and carbon dioxide, withoutcreating sludge.

Table 4 shows experiment results in a pilot plantfor 5 months where identical raw water has beentreated both without and with additional ozone forcomparison.

4. Conclusion

We introduced some of the concepts and FujiElectric’s technologies for advanced water treatment inwaterworks and sewerage system. At Fuji Electric, wewill continue to employ new technology and to developmore efficient and more highly advanced treatmentsystems in the future.


Yusuke YamaguchiMamoru Sato

Engineering and Construction Techniquesfor Waterworks and Sewerage Systems

1. Introduction

Engineering can be defined as means and proce-dures for promoting system configuration and con-structing a plant through the whole process of plan-ning of the plant to its maintenance and managementafter the completion and depends largely on humanintellectual work. Along with the greater sophistica-tion and larger scale of plants, engineering work israpidly increasing in complexity and scale. Specialemphasis has been placed on engineering work be-cause its quality greatly affects the quality and cost ofthe entire system.

On behalf of the company, a “site superintendent”is given authority and made responsible for onsiteconstruction to complete a job to a purchaser’s satisfac-tion by the delivery date. It is important to establishconstruction techniques for this purpose.

In recent years, there have been urgent demandsfor public works in Japan to reduce cost and guaranteequality in response to the trends toward an improvedbidding and contracting system and business globaliza-

Fig.1 Schematic diagram of CALS in public works and private companies

Fuji Electric (head office

and branches)

Fuji Electric (factories)

Fuji Electric (construction

site)

™Materials suppliers

™Construction corporations

™Civil engineering/machine manufac-turing corporations

Various informa-tion systems

™Design consultant ™Construction

design firm

Construction-related corporations

Link-up of networks

In-house CALS

Maintenance

Construction

Production

Design

Arrangements

Order intake

Fuji Electric

Shared virtual DB Lifecycle

Mana-gement

Const-ruction Design

Investi-gation

Planning

Other industries

Overseas companiesThe people

Local governments

Local agencies of the above

Government agencies

Purchaser/Facility superintendent

Individual DB

tion. Furthermore, relaxation of various restrictionsand computerization in the public sector are stronglydemanded as part of administrative reform. Increasedefficiency and labor savings are also required for publicworks.

This paper introduces Fuji Electric’s handling ofCALS (commerce at light speed), which is of increasingimportance to engineering and construction tech-niques.

2. CALS

CALS was initiated by the Department of Defense(DOD) of the United States and is now performedworldwide led by private sectors.

Within private industry in Japan, CALS is activelyperformed under the guidance of the Ministry ofInternational Trade and Industry (MITI). Withinpublic works, “basic concepts for upgrading CALS/ECfor construction works” have been drafted by the“Study Group for an Integrated Information System toSupporting Public Works” as promoted by the Ministry

Engineering and Construction Techniques for Waterworks and Sewerage Systems 145

Fig.2 Key system for arrangements of plant components:ACTION

of Construction.In the CALS/EC for construction works, all stages

such as planning, design, cost estimate, bidding,contract, construction and maintenance are performedbased on CALS for the purpose of lower total cost,greater efficiency and improved quality. An “actionprogram” was prepared in 1997 and specific field testsare being implemented.

Figure 1 shows a schematic diagram of CALSimplementation within public works and within aprivate company.

3. Fuji Electric’s Handling of CALS

Fuji Electric has been participating in committeesof the Inter-company Electronic Commerce Promoting

Settlement of accounts

Accounts payable/ payment

Accounts receivable/ recovery

Totaling of sales

Totaling of orders

Factory system

Division system

Sales agents/associated com-panies

Overseas locations

ACTION and related systems

ACTION(EDI)

Organization and CALS Promoting Organization, pro-moted by MITI for the investigation, research, popular-ization, and education about CALS.

While implementing CALS, Fuji Electric and itsassociated companies are promoting business renova-tion of the whole Fuji Group by encouraging anupgrade of the information infrastructure, such asexpanding networks and restructuring all key systems,aiming at data digitization, information sharing andpaperless business.

3.1 Key system for plant-component arrangementsIn corporate management, to restructure all busi-

ness processes of a group of companies into a whole,cooperation is becoming increasingly important be-tween departments concerned with sales, design, man-ufacturing, physical distribution and onsite construc-tion.

In the restructuring of key system for plant-component arrangements, the primary objective is toshare information within the group and build anintegrated system to support order receipt, arrange-ments, sales and schedule control for the purpose ofimproving the function (F), quality (Q), cost (C),delivery (D), safety (S), and efficiency in overheaddepartments. Information sharing can be achieved bylinking key system with systems of various depart-ments in the company and its associated companies.(refer to Fig. 2)

3.2 Integrated information system in public systems divisionIn public systems division, purchasers are the

Fig.3 Integrated information system in public systems division

Associated companiesManufactures from which components are supplied

Purchaser Intracompany Mobile Site construction offices

ExtranetInternetIntranetC/S system

Network (WAN, LAN) mobile certification

Engineering information

Communication informationWeb server

After-sales service

Site construction support

Mobile

Factory/parties concerned

Design/manufac-turing support

Management information

Data transfer

<Key system>

Site

Associated companies

Factory

Design

Engineering

Sales

Adminis-tration

Parties concerned

After-sales service

Site construction

Shipment from factoryManufacturingDesignArrangementsOrder

intake

Business flow

ACTION

SJOINT

C/S C/S

C/S

C/S


ministries, their agencies and local governmentsthroughout Japan. Since many sales locations andsites are scattered throughout the country, businessliaison through networks is very important.

Due to company-wide computerization, internaland external company telecommunication infrastruc-tures such as intra-company networks and ISDN weredramatically improved, and information processingtechnologies such as the internet and mobile communi-cation have made great advancement. This allows theintegration of conventional business support systemsand the construction of an integrated informationsystem (Fig. 3) that covers all relevant departments,site construction offices and associated companies,contributing to improved engineering work.

In public systems division, an intranet and anextranet were constructed as corporate CALS systemsand put into operation. The former handles informa-tion ranging from order intake and site construction tomaintenance throughout product lifecycles (informa-tion about communication, management and engineer-ing). The latter handles information transfers andbusiness liaisons with associated companies.

The sharing of information through the intranet isdescribed below.(1) Sharing of communication information

Communication among participant members isvery important for unifying members’ desires in thesame direction and attaining an objective. A net-worked system and digitization eliminates location andtime restrictions.

E-mail, a bulletin board system, an electronicconference room and schedule management are config-ured on the intranet as part of the shared communica-tion information.(2) Sharing of management information

Within the public systems division, an informationsystem (SJOINT) was formed in 1993 that has beenutilized for the division’s business. It is consistent

information, from order intake through site construc-tion for individual projects, in order to increase theefficiency of paperwork and share the information withother concerned parties.

ACTION system is only used to enter the data ofarrangements information, avoiding duplicate entries.Not only the division’s data but data from factories areautomatically transferred from ACTION to SJOINT,where updated data is always available.(3) Sharing of engineering information

In the manufacture, construction and maintenanceof a plant system, not only is communication andmanagement information necessary, but engineeringinformation such as communication notes, specifica-tions and drawings is also essential.

The aforementioned information is processed andaltered, new information is created over the course ofplant processes from order intake through site con-struction, and an enormous amount of data is trans-ferred from upstream to downstream divisions. Greatcare must be taken so that no errors occur duringprocessing and alteration.

For these reasons, the company constructed asystem using CASE (computer aided system & soft-ware engineering) and has been improving the produc-tivity and quality of delivered systems.

The above activities are, however, informationsharing between limited sections, and still much effortmust be expended to exchange engineering informationbetween organizational groups.

Information used while conducting a plant’s busi-ness includes a variety of documents, drawings, photo-graphs, videos, spreadsheets and databases. There aremany technical challenges to the distribution of digi-tized information of the above, and to the digitization,distribution and exchange of past information assets,for which high expectations are placed upon therealization of EDI (electric data interchange) to stan-dardize information exchange.

Figure 4 shows the top page of an intranet.

3.3 Project homepageIn this intranet system, all the members concerned

with the project share information from order intake toshipment and maintenance. Information is managedfor each project to increase the information transferspeed, to attain instantaneous information and topromote each project smoothly.

Shared information about each project can beentered in the form of a homepage (Fig. 5) and all theinformation about that project can be obtained on thehomepage.

Communication information and information cre-ated by the support and management systems to bedescribed later can be shared by making the informa-tion public as FQCDS information.

However, specifications and working drawings,which are the result of engineering, have not yet been

Fig.4 Example of intranet homepage

Engineering and Construction Techniques for Waterworks and Sewerage Systems 147

Fig.5 Example of project homepage Fig.6 Concept of software generation from specifications

exchanged nor reused seamlessly.Regarding the distribution of drawings, since CAD

tools are not standardized there are many challengesto be overcome for the exchange of such information,including data exchange.

For this reason, PDF (portable document format)files suitable for use in information distribution wereintroduced. CAD drawings and past paper-basedassets were converted from a raster image processorand information distribution via the internet is beingevaluated.

In addition, management and database informa-tion entered through a C/S (client/server) system isavailable and can be viewed with a Web browser byconnecting a Web server and database. This contrib-utes to improved management of various divisionsbased upon correct and wide-ranging information.

The function of entering data into a database usinga Web browser was constructed by means of CGI(common gate interface) and a JAVA script, and hasbegun operation as a business system.

There are many types of content and informationmedia to be shared in engineering tasks. It is requiredto develop CALS constituent technologies such technol-ogy to digitize content and information, workflowtechniques (seal of approval, confirmation), technologyto control altered information and security technolo-gies.

3.4 Support system for design and manufacturingDesign, manufacturing and testing have been

mechanized and automated.In present control systems where information

equipment plays a pivotal role, improved quality andproductivity of software related engineering tasks isstrongly demanded.

Fuji Electric constructed and has been utilizing anengineering environment which can provide integratedsupport not only to a monitoring and control system forwater treatment FAINS but also to control systems for

other fields.The support system aims at improving quality and

productivity of engineering tasks by automaticallygenerating downstream information from upstreaminformation. Basic concepts for system design, soft-ware design and test scheduling to achieve this goalare listed below.(1) Integration of working environment in all processes(2) Centralized control of data in all processes(3) Higher level of software specification description(4) Automatic generation of control software from

specifications(5) Extraction of engineering information from speci-

ficationsThese concepts create an environment for a com-

mon platform that can be used uniformly with variouspackages. Generated information is publicly displayedon a project homepage, conveyed to other divisions,and utilized for copying and processing by downstreamdivisions.

Figure 6 shows the concept of software generation.

3.5 Site construction support systemFigure 7 shows management tasks for site con-

struction. A site superintendent must fully under-stand the objective and contents of the constructionand manage it (schedule, materials, quality, laborcosts, safety, paper work, costs, etc.) in accordancewith drawings, specifications, related laws and regula-tions and contract conditions.

Site superintendents must always exercise leader-ship in solving problems, give accurate instructionsand orders to subordinates and workers, and must alsocomplete the construction smoothly by effectively com-municating with purchasers, design engineers, con-struction companies and machine manufacturers

In the past, however, sites have been treated as ifthey were solitary islands with regard to information.Site construction is managed as if in a virtual factory,but in realty, there are many challenges in terms ofproduction rationalization systems and job supportthrough networks, compared with those in a factory.

In response to this situation, along with the

L 1DND 1NND 2OR 3AN 5O 6AN 1OR 7( 8

& R0

3. Match between documents and specifications

2. Quality improvement

1.Productivity improvement

Logical table

Data flow

Logic flow

Control flow

Switch flow

ControllerProgram

Monitor

Editor

Conven- tional process

DocumentorControl specifica-tions

Purchaser


Fig.7 Management tasks for site construction

Site superin-tendent

Site construction

Paper-work

control

Quality control

Cost control

Labor manage-

mentSafety control

Materials control

Schedule control

Con-struction manage-

ment

Authorities concerned

Electric power

companies

Companies concerned with con-struction

Electric machinery

manu-facturers

Machine manufac-

turers

Civil engi-neering

companies

Construc-tion

companies

Design offices

Purchaser

construction of a mobile network environment, FujiElectric has constructed and started operation of anenvironment where company divisions and remotesites can exchange information interactively. Sitesupport systems are intended to improve quality andreduce costs of construction management, allowing sitesuperintendents to perform efficient jobs and allparties concerned to convey information at higherspeed.

Collection of site construction information for eachproject on the project homepage allows companydivisions and remote sites to share information, andmakes it easy to post and to reuse various drawingsand materials onsite.

In addition, laws and regulations related to siteconstruction, internal regulations for safety and sani-tation, and job manuals are posted on the homepage sothat they may be thoroughly understood by sitesuperintendents scattered across the country. Thesupport system reduces jobs in administrative depart-ments that handle the distribution of documents andnotification of their alterations. The time required forinformation conveyance can be considerably reduced by

Fig.8 Example of homepage for weekly schedule andperformance

the system compared with mail or home delivery in theform of paper.

Figure 8 shows an example homepage for a weeklyschedule and performance.

4. Conclusion

This paper has presented Fuji Electric’s approachto engineering and construction techniques for water-works and sewerage systems, focussing mainly onFuji’s support system from the viewpoint of informa-tion sharing.

Browsing, processing, conversion and generation ofdigitized information are performed throughout thelifecycles of products and facilities according to theCALS concept, “data is only once created and used asmany times as possible.” Introduced as an example inthis paper is the CALS implementation from orderintake to delivery and maintenance of waterworks andsewerage systems products in a group of companies.

Application of ISO9000S (quality ISO) andISO14000 (environment ISO) to public works areunder study. Fuji Electric is pushing hard to obtainmore ISO certifications. CALS is an efficient means ofhandling the thorough documentation (procedures,evidences) required for obtaining ISO certification.

Fuji Electric’s CALS has just begun. Fuji Electricwill continue to promote and spread CALS applicationswithin companies, capitalizing on experiences andtechniques accumulated in CALS activities.

AMERICA

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