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6-3  Outline of product technology (7 companies)

6-3-1 KUBOTACorporation

6-3-1-1 Ductileironpipeswithhazard-resilientjointsThe structure of a ductile iron pipe with hazard-resilient joints is designed so that the joints between the pipes

expand and contract. The spigot is also unable to pull out of the socket even if the pipe is fully extended because the lock ring engages with the spigot projection. In a pipeline installed underground, even if a single joint be-comes fully extended, the adjacent pipes will be pulled one after the other, allowing for any ground deformation to be absorbed along the entire pipeline.

Fitted with these features, ductile iron pipes with hazard-resilient joints suffered no damage even in major earthquakes of the past. Pipelines in actual use, which have withstood major earthquakes, were used to investi-gate their behaviour, and to verify the effectiveness of chain-structure pipelines and their seismic resistance even against repeated major earthquakes. It has also been confirmed that the pull-out resistant performance of pipes that have been used for about 40 years has not changed from its initial values.

In addition to earthquake countermeasures against seismic vibrations and liquefaction, there have also been many cases of pipelines withstanding other ground de-formation caused by natural disasters, such as heavy rains and tsunamis.

With a view to 100 years into the future, we recommend ductile iron pipes with hazard-resilient joints that can be safely used in pipelines, as a measure against natural disas-ters such as earthquakes, typhoons, landslides, tsunamis.

Figure 6-3-1-1 Lift-up demonstration of GX-type duc-tile iron pipes with a nominal diameter of 300 mm

Figure 6-3-1-2　 NS-type ductile iron pipes with a nominal diameter of 300 mm with no reported damage following the Great East Japan Earth-quake, despite being scoured by tsunamis and knocked by ship-ping containers and other heavy objects (Ishinomaki City, Miyagi Prefecture)

Figure 6-3-1-3 NS-type ductile iron pipes with nominal diameters of 100 and 75 mm, located under riverside roads, with no reported leaks or damage following heavy rains (Matsuyama City, Ehime Prefec-ture)

Φ300NS

φ75NS

φ100NS

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6-3-1-2 Membranebioreactor(MBR)The membrane bioreactor (MBR) process is a method of treating wastewater which combines the biological

treatment of activated sludge and the separation of solids from liquids using membranes. A feature of the MBR is its small footprint and high effluent quality free from colon bacilli and suspended solids (SS). Kubota began developing the MBR in the late 1980s. Since about 1990, it has been applied to various areas, such as septic tanks, industrial wastewater and sewage, with upwards of 6,000 applications in the field. The scale of wastewa-ter treatment plants has gradually become larger, including cases of 20,000 m3 per day at the Semboku Sewage Treatment Plant in the Japanese city of Sakai, and 159,000 m3 per day at the Canton Water Reclamation Facil-ity in the United States.

On the other hand, the biggest issue for the MBR was that it consumed more power than conventional pro-cesses. To achieve energy savings, aside from developing a new model of membrane unit as well as a siphon filtration system and other peripheral equipment, Kubota also set about developing software technologies for controlling airflow volume in order to reduce the power used by air blowers, which accounts for most of the power consumed. As a result of these efforts, power consumption was reduced to the same level as conven-tional processes. Going forward, it is expected that the applications of the MBR will widen further as a treat-ment method that is also effective from the perspective of recycling sewage, thereby contributing to recycling of the world’s water resources.

Figure 6-3-1-4   Process flow in the MBR

Figure 6-3-1-5 Exterior view of a mem-brane unit

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6-3-2 TAISEIKIKOCo.,ltd.

6-3-2-1 TAI-FLEXDescriptionofductileironexpansionjoint

Earthquakes and other natural disasters can cause fissures, landslides or liquefaction, which can lead to ground movement. Such ground movement can have a significant impact on essential utilities, and with water pipes, there is a strong chance of pipes slipping out from joints or the joints becoming damaged. Environments where pipes are buried, such as soft ground or the boundary between different strata, are also susceptible to ground movement.

Ductile iron expansion joints are flexible joints with excellent slip-out resistance to counter such ground movements.

1) Features, structure and performanceThe ball-type structure gives the joint flexibility allowing it to follow considerable bending, and incorporat-

ing the expansion/contraction function inside the ball enables the pipeline to accommodate ground movement (Figures 6-3-2-1 and 6-3-2-2). Furthermore, Taisei Kiko’s unique assembly method achieves a non-bolt struc-ture, with no connections using bolt and nut. This makes for an expansion joint with a high slip-out resistance of at least 3D kN (D: nominal diameter) at full expanded state.

2) Performance classifications

Item Class Performance of joint

Slip-out resistance A 3D kN or more (D: nominal diameter)

Expansion/contractionperformance S-1 ±0.01 ℓmm or more (ℓ: Effective length of single pipe)

Joint deflection angle M-1 ±15° or more

*Classifications are per ISO 16134 Earthquake- and subsidence-resistant design of ductile iron pipelines

Expansion/contractionExpansion/contraction

BendBendSubsidenceSubsidence

Casing BallRubbergasket Casing cover

Rubber gasketLock ring

Figure 6-3-2-1 Structure of expansion joint Figure 6-3-2-2 Expansion/contraction, bend and sub-sidence performance

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3) ApplicationsFigure 6-3-2-3 shows the example of a fixed inlet and outlet pipe from a structure. Due to the risk of water

leaking if the pipe slips out from subsidence, the expansion joint has been installed so the joint can deviate ac-cording to the subsiding pipe in order to protect the pipeline. Figure 6-3-2-4 shows the example of an expansion joint being used in an area of large displacement between an abutment and underground pipes.

6-3-2-2 EarthquakeResistantReinforcementFittingsDescriptionofreinforcementfittingsusedonjointsofexistingductilepipes

While the penetration rate of earthquake resistant pipes as an earthquake countermeasure is progressively improving, there are currently many K-type ductile pipes being used which have not yet reached the end of their useful lives. As a means of counteracting these pipes slipping apart at joints, Taisei Kiko considered a way of increasing the slip-out resistance at joints by using reinforcement fittings. With this method, work on existing pipes can be carried out with the water still running through them, without having to shut off the water supply. This method has many other practical advantages, including less excavation work, shorter completion times, and more effective use of resources. Taisei Kiko rates the method as an effective option for pipelines against ground subsidence and earthquakes. For instance, the method can be applied in urban areas and other locations where the water supply cannot be shut off, and it can also be done in stages in cases where traffic restrictions must be kept short or where work is scheduled for short night-time shifts, and in places where replacement with new pipes is not possible.

1) Features, structure and performanceThe reinforcement fitting is arranged around the outside of the joint, and the wedge-structured slip-out pre-

vention fixed on the spigot is hooked onto the flange of the existing socket (Figure 6-3-2-5). A feature of the fitting is that it gives flexibility to the movement of the joint by means of a hook structure to the socket that is not fastened using nuts and bolts. This means that the pipeline can cope with subsidence and other ground movement as any bend performance is maintained even after the reinforcement fitting has been installed. Fur-thermore, a joint with a reinforcement fitting installed has an axial slip-out resistance of 3D kN (D is nominal diameter in mm), equivalent to that of an earthquake-resistant fitting.

Double-type expansion joint

Ecce

ntric

Ground subsidence

Figure 6-3-2-3 Pipe installed around a struc-ture

Figure 6-3-2-4 Installation of an expansion joint

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2) Method of construction The disengaged reinforcement fitting is placed over the joint, and connected together to form a ring. The bolts

are tightened, and construction is complete. The only construction management is the tightening torque of the bolts. No special tools are required. Also, with consideration being given to the construction work at the design stage, rather than separately attaching each side of the reinforcement fitting, the fitting is unloaded as one (Fig-ure 6-3-2-6), meaning that the crane only needs to be operated once. In addition, it also reduces the lifting work underneath the pipe, and reduces the burden on workers.

written by: Hisakazu AsaiTechnical Department

TAISEI KIKO CO., LTD.

Figure 6-3-2-6 Method for installing a rein-forcement fitting

Figure 6-3-2-7 An installed reinforce-ment fitting (φ400)

Reinforcement fittingHook structure on socket

Ductile pipe

Rubber ring formed Existing glandaccording to existing pipe

Wedge structure on spigot

Reinforcement fitting

Ductile pipesocket

Ductile pipespigot

Figure 6-3-2-5  Joint structure of reinforcement fitting

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6-3-3 Hitachi,Ltd.

InformationandControlSystemsforWaterSupplyandSewerageElectrical equipment as well as information and control systems used in water supply and sewerage in Japan

have changed significantly with the times. In the early days, operating the various electrical equipment installed in water purification plants, sewage

treatment plants, pumping stations and so on involved operators directly controlling switches on the actual ma-chines. However, with advances in automated control from a central monitoring panel, by the 1960s, equipment with automatically controlled instrumentation was being actively introduced.

During the 1970s and 1980s, automatic control using digital computers became a reality, as did monitoring and operation via CRT monitors, bringing about a major technological change.

Then in the 1990s, progress was made in the integrated control of electricity, instrumentation and computers (EIC). As for today, systems being introduced include those based on the scale of business, remote monitoring and control systems that support wide-area management, and distributed systems capable of flexibly accom-modating gradual extensions and upgrades. Information and control systems can now be offered, tailored to the natural environment and society of the respective country or region.

Along with developments in hardware, functional enhancements have also been made to software. During the 1970s, systems were established for controlling the injection of chemicals and the flocculation process. To date, a wide range of systems have been put into practical use, including systems controlling the operation of ad-vanced water purification and membrane filtration processes, and systems designed to reduce the burden of sewage treatment on the environment.

Nowadays, instead of just monitoring and control systems for individual facilities, wide-area management systems are being used which extend across multiple facilities. For instance, at water utilities, systems are being used which support the planning of day-to-day water supply operations based on conditions at water sources and at facilities and on forecasts for water demand.

Japan’s water supply utilities and sewage utilities each account for just under 1% of all electricity consump-tion nationwide. As a way of realising energy savings, information and control technologies have been intro-duced which do not necessitate any significant rebuilding of facilities. Examples of technologies that have been put to practical use include technology using real-time pipe network simulation to optimise control of water pressure in water distributing pipes, and technology using ammonia sensors to control and improve the effi-ciency of the aeration process at advanced sewage treatment facilities (where ammonium nitrogen is removed).

As the nation’s population declines, two issues facing Japan are a decrease in technical staff working in water supply and sewerage and the transfer of technologies. A promising solution for these issues going forward is the application of latest technologies, such as IoT and AI, to improving business efficiency and to transferring the experience of veteran engineers.

written by: Takahiro TachiHitachi,Ltd

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6-3-4 SwingCorporation

TechnologyforRecoveringPhosphorusfromSewage:Rephosmaster®

As an important element essential for sustaining life and for industrial use, phosphorus is such a scarce re-source in Japan that the country relies completely on imports. On the other hand, as a kind of pollutant in waste-water, it is also one of the causes leading to eutrophication in natural water bodies and the formation of scale in sewage treatment plants. In recent years, there have been widespread efforts to effectively remove the phospho-rus in sewage and recover it for reuse.

Rephosmaster®, developed by Swing Corporation, is an innovative phosphorus recovery technology that uses a completely mixed crystallisation reactor capable of efficiently recovering phosphorus contained in digested sludge in the form of magnesium ammonium phosphate (MAP), known as struvite. Phosphorus was usually recovered with the filtrate from the dewatering process of digested sludge, but with Rephosmaster®, digested sludge can be processed directly. For this reason, in addition to the soluble phosphate, chemically precipitated phosphate occurring naturally during sludge digestion, such as the struvite, can also be recovered, and so the phosphorus recovery efficiency can be improved vastly.

Rephosmaster® was selected by the Ministry of Land, Infrastructure, Transport and Tourism (MLIT) for the Breakthrough by Dynamic Approach in Sewage High Technology Project (B-DASH Project; research commis-sioned by the National Institute for Land and Infrastructure Management (NILIM)). Full-scale demonstration of the performance of Rephosmaster® during long-term operation was conducted in fiscal 2012–2013 in Higashi-nada Sewage Treatment Plant, Kobe City, and the efficiency of phosphorus recovery and the effectiveness of the recovered struvite as fertiliser were evaluated. The full-scale demonstration plant is still in operation. Recovered struvite is processed into a fertiliser product suitable for agricultural use, and there are ongoing efforts for its commercialisation to expand the product quantity.

Further application of Rephosmaster® is expected, as it is a technology capable of recycling phosphorus con-tained in sewage and reusing it as fertiliser in a practical and economic way, thereby contributing to a sustain-able and resource-recycling society.

written by: Shojiro WatanabeEngineering & Development Division

Municipa Water & Sewage Engineering Dept. Swing Corporation

Sludge after phosphorus removal

Digested Sludge

DewateredSludge

Dehydrater

forFertiliser

Recovered StruviteRephosmaster®(Phosphorus Recovery Plant)

Digester

Figure 6-3-4-1 Phosphorus recovery process

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6-3-5 COSMOKOKICO.,LTD.

PipeworkunderpressurePipework under pressure is a construction method that enables a branch to be fitted or a valve to be inserted

without shutting off the water supply. Not only does this method contribute to a better service for water users, but it also reduces the workload for water service operators in a variety of ways.

The method of fitting a branch without shutting off the water supply involves attaching a split tee, a gate valve and a boring machine in that order to the pipe under pressure, forming a pressure vessel at the branch, and bor-ing into the pipe while water continues to flow.

The construction method for inserting a valve involves attaching an upright divided fitting to the pipe under pressure, setting up a process valve and boring machine in that order, to form a cylindrical pressure vessel. Us-ing a hole saw cutter larger in diameter than the main pipe, the main pipe inside the fitting is sliced in rounds and the coupon is removed. Using an inserting machine, a specially designed valve is inserted into the fitting and fixed in place. As for the pressure resistance when inserting the valve, the pressure either side of the valve is kept level by means of a pressure-equalising hose connecting the upper vessel to the fitting, thereby relieving the resistance during insertion and the load on the rubber seal.

Phase1: Boring Phase2: Removal Phase3: Connect New Pipe

Valve (Open)

Fitting Boring Machine

Hole Saw Cutter

New Pipe Valve (Close)

Figure 6-3-5-1 Branch Work Under Pressure Mechanism

Phase 1: Boring Phase 2: Valve Setting Phase 3: Inserting Valve

Gate Valve (Open)

Hole Saw Cutter Gate Valve (Open)

Gate Valve (Close)

Valve Body

Inserting Machine Boring Machine

Figure 6-3-5-2 Inserting Mechanism

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Public-Private Partnerships in Water Supply and Sewerage Systems

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These methods can also be applied to high water pressure and large diameter pipelines, and in 2005, insertion of a valve in a pipeline measuring 2,600 mm in diameter was certified as a Guinness World Record.

Meanwhile, for smaller pipes in urban areas, the Plug 3 type construction method is used as a simple way of inserting valves using compact equipment. The Plug 3 type construction method involves mounting a split tee, a process valve and a boring machine facing upward to form a pressure vessel on the branch pipe. After boring a hole of the same diameter, a shell-type rubber seal valve is attached to the branch. A valve plug pushed down from the bored opening extends into the pipe, thereby stopping the water. Depending on the inner surface of the pipe, the plug may not completely stop the water, but given that the method is less expensive and can be per-formed with smaller equipment than the inserted valve, the plug is often used in Japan as a temporary valve used in construction.

In recent years, Japan has been transitioning to earthquake-resistant pipelines, and as a consequence, Cosmo Koki has also been taking action to make the split tee used in the pipework under pressure resistant to earth-quakes. Variations of the method have also increased in proportion to customer needs, such as methods for re-placing pipeline fixtures, including air valves or fire hydrants, without interrupting the water supply, and the pipework under pressure for bypassing a spot pipe removal.

Developments overseas have so far centred on activities supporting water supply projects through Official Development Assistance (ODA). But as strong interest is being shown for Japan’s pipework under pressure, praised as being of world-class standard, it is expected that the methods will play a part in infrastructure ser-vices—in reducing the suspension of water supply—in countries around the world that are becoming increas-ingly urbanised.

written by: Shinji YamanouchiDevelopment Department Director

Cosmo Koki co.,ltd

Setting (Water Supply) Shutting (Water Stop)

Fitting

Pipe

Plug (Open) Plug (Close)

Pipe

Figure 6-3-5-3 Plug 3 Type Plug open and close

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6-3-6 MEIDENSHACORPORATION

CeramicFlat-SheetMembraneSystemsforWaterPurificationandSewerageTreatmentMeidensha’s ceramic flat-sheet membranes are used by immersing them in water tanks. With applications in

water purification and sewerage treatment sectors, the method is effective for the water purification of highly turbid river water and for membrane bioreactors (MBR) which retain high concentrations of MLSS within the tank in which the membrane is immersed. Following are some of the features of ceramic flat-sheet membranes.

1) Enhanced permeabilityMicrofiltration (MF) membrane with a nominal pore size of 0.1 μm has a pure water permeability of 40 or

more m3 per m2 per day at a water temperature of 25°C and pressure of 100 kPa, and so contributes to space-saving installations.

2) Enhanced strengthSince high-pressure washing is possible, the filtration performance of the membrane can be restored by

physically washing the membrane surface. Also, since there is little abrasion of the membrane surface caused by activated charcoal, it can be integrated with the adsorption process for trace amounts of organic compounds, meaning space savings for the overall process are also possible.

3) Outstanding chemical resistanceSince the membrane is made from a material that can also withstand chemical cleaning using sodium

hypochlorite and acid, it can be expected to have an increased operational life.

In water purification, Meidensha has already obtained various domestic and international certifications, so the membrane can be used with confidence. Certifications include the de facto international standard, NSF/ANSI 61 and 419, plus the domestic standards, Membrane Module Certification for Water Supply and the Certification of Water Treatment Equipment.

In wastewater treatment too, Meidensha has received California’s Title 22 certification, meaning the membrane can be applied to the reuse of treated water—demand for which is expected to grow in the future.

In sewerage and wastewater treatments in Japan, commercialisation of membrane systems has started with wastewater from food-processing factories. Meidensha is also proceeding with technology development to adapt to public sewerage, and utilising the features of membranes, is demonstrating the potential for operations at low power consumption (0.39 kWh/m3 for the whole process, including MBR and pretreatment).

Examples of facilities delivered overseas which process a minimum of 10,000 m3 per day are an MBR for use in public sewerage and a membrane filtration system for use at a water purification plant in Singapore. Meidensha also has a track record in water purification and sewerage treatment and various wastewater treatment technologies in North America, the Middle East, China, Taiwan and Korea.

written by: Shoichi SameshimaWIS Product & Ecosystem Development Division Water Infrastructure Systems (WIS) Business Unit

MEIDENSHA CORPORATTION

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6-3-7 METAWATER.Co.,ltd.

OzoneTreatmentTechnologiesforWaterandWastewaterServicesMETAWATER’s ozone technologies have been applied in the fields of water and wastewater and also in

various industries since 1972.

(1) Highlyreliableozonegenerationsystem METAWATER supplies ozone generation systems that employ a high-performance IGBT inverter for pow-

er supply, combined with glass-lined electrodes that have an extremely low failure rate. The electrodes manufactured in Japan are highly accurate and capable of maintaining excellent performance over a long period of time. METAWATER was the first company to supply an air-fed type system, with a high ozone concentration of 50 g/Nm3, to water purification plants. Its oxygen-fed type systems are the only ones in the world to use the Double Cooling System which applies water cooling to both the internal and external sur-face of the electrodes. It also uses particularly high-precision electrodes in the form of μ-GAP Technology. The system has been supplied to about 50 plants for primarily water and wastewater treatment in North America and China. At present, the system is sold by the METAWATER Group company, Aqua-Aerobic Systems, Inc. as Aqua ElectrOzoneTM in North America.

(2) Applicationofozonetreatmentinwaterpurification Ozone treatment has been introduced into more than 60 water purification plants in Japan, especially in

large cities. The primary objectives of the treatment include / odour removal, trihalomethane formation potential (THMFP) reduction, and manganese oxidation. METAWATER’s ozone treatment systems have been introduced in many plants, including large-scale water purification plants with a capacity of more than 1 million m3/day, and are helping to improve the quality of tap water in Japan.

METAWATER is also committed to process development. Recent efforts include a demonstration test of the advanced oxidation process (AOP) in water purification. The objective is to control the odour and bromates generation during periods of low water temperature.

(3) Applicationofozonetreatmentinwastewatertreatment In the area of wastewater, the objectives of ozone treatment in Japan include water reuse and environmental

protection in water where effluent is discharged. In addition to being effective as a disinfectant, ozone is also effective for decolourization and deodorization. Therefore it can be used to improve the safety and comfort of water. To further improve the quality of reclaimed water, METAWATER supplies the combined system of ozone treatment with ceramic membrane filtration. Ozone enhances the membrane filtration per-formance, and so is effective in improving flux. The treated water from the process is used, for instance, to water gardens and flush toilets in office buildings.

(4) Systemsdesigncombiningmechanicalandelectricaltechnologies METAWATER does more than just supply high-performance equipment for water treatment, such as ozone

generation system and ceramic membrane filtration system. It also provides operation, control and monitor-ing systems to build highly efficient and highly reliable water treatment systems.

Written by: Ryutaro TakahashiSenior Manager

Water Supply Engineering Dept. Plant Engineering Div.

METAWATER Co., Ltd.