case studies

12th June 2018 by Iseki Iseki

PULAU INDAH, INDUSTRIAL PARK, Malaysia

Client: Central Spectrum (M) Sdn Bhd
Country: Malaysia
Length of Pipe: 5 km
No. of Valves: 100
Volume of Flow: 30 litres/second
Specialist Feature: Reduced sewer depths through innovative design to negotiate the deep storm water drains

Pulau Indah is an island off the coast of Malaysia, South-west of the capital city Kuala Lumpur. The ground conditions on the island are mangrove swamp overlain with fine sand and a water table approximately 1 metre below the existing ground levels. With storm water drains installed at depths of up to 3 metres, the previously designed gravity system had main sewers 5 metres deep and 4 pumping stations each at a depth of 10 metres from the finished ground levels. With the existing soil conditions, the difficulty and cost of installing the gravity system made it an unattractive solution for the client.

Iseki Redivac designed a vacuum system with the “crossover” pipes from the valve chambers passing through the storm drains at a high level, thereby allowing the main vacuum sewers to be installed at shallow depths. A single vacuum station replaced the four gravity pumping stations by collecting the sewage from the entire development and pumping it directly to the nearby sewage treatment plant. With sewer and chamber depths being considerably reduced, a 40 % capital cost saving was passed onto the client and the single vacuum station significantly reduced the operation and maintenance costs of the local water authority.

Reclaimed Swamp Land

Vacuum Pipework
Vacuum sewers constructed from PN8 polyethylene pipes jointed using electrofusion welding techniques.Vacuum Station Equipment
The two storey station comprises three rotary vane vacuum pumps, a 13.5m³ vacuum vessel and three centrifugal screw sewage discharge pumps.A motor control centre complete with PLC logic controls the M&E equipment automatically and notifies the local water authority when attendance is required at the station via an automatic dial-up facility built within the control centre.

Summary
Iseki’s innovative approach to design overcame the engineering problems caused by the difficult ground conditions and offered a 40% capital cost saving to the client and reduced the operational costs of the local water authority.

Possible Applications for Iseki Redivac’s Technology
Rural community sewerage systems
Industrial developments
Supply bases
Housing development/compounds
Hazardous waste collection
Airports & military installations
Beach developments
Remote villages

Pulau Indah

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Deep Storm Water Drains

Cable works and trenching

High Water Table
Cost effective solutions to many difficult drainage problems

Installation underway in narrow trenches. Cost-effective solutions to many difficult drainage problems

12th June 2018 by Iseki Iseki

NADARZYN, Poland

Client: Local Administration of Nadarzyn
Country: Poland
Length of Pipe: 16km
No. of Valves: 244
Volume of Flow: 20 litres/second
Specialist Feature: Widely scattered building in narrow streets. Difficult terrain with high water table.

Nadarzyn is a town situated approximately 30 km south of the capital city of Poland, Warsaw. The town and the surrounding area is flat with Nadarzyn itself being sparsely populated with houses and local amenities widely spread.

The water table is only approximately 1m below the existing ground level and trial holes found the soil conditions to be very poor. With these challenging ground conditions and the cost implications associated with installing a conventional gravity system it became apparent that an alternative solution would be needed. ISA POLSKA Sp. z.o.o. met the challenge by designing a vacuum sewerage system which vastly reduced the construction period and the projects capital costs.

With sewer and chamber depths being considerably reduced, a 35% capital cost saving was passed onto the client and the single vacuum station significantly reduce the operation and maintenance costs of the local water company.

Vacuum Pipework
The polyethylene pipework in sizes ranging from Ø90mm to Ø280mm.

Two submersible discharge pumps each rated at 20 l/s.

Steel cylindrical 16m³ vacuum vessel, vertically mounted underground on a concrete base.

Fully automated motor control centre is uses a programmable PLC to control the operation of vacuum and discharge pumps.

The valve monitoring console is situated alongside the MCC and monitors the open/closed mode of each interface valve located around the town.

Exhaust gases are filtered by passing them through a biological filter located outside the vacuum station building.

Vacuum Station Equipment
Three vacuum pumps manufactured by Busch each with a capacity of 630m³/hr each.

The sewage discharge pumps installed in the Gorefield vacuum station are centrifugal screw type pumps rated at 17l/s supplied by Hidrostal Ltd.

The vacuum vessel is fully coated inside and out as well as being certified to Lloyds standards. The motor control centre is fully automatic with PLC logic control. All pumps start in rotation and all conditions are monitored with a data logging system.

A PC based valve monitoring console was designed to allow comprehensive interrogation of each individual vacuum interface valve. This data provides quick and easy identification of potential problems long before it could lead to a line failure.

Summary
The ‘Vacuum Way’ proved to be the ideal solution to overcome the engineering difficulties resulting from the difficult ground conditions and offered a 35% capital cost saving to the client while minimising the operational cost for the local water company.

Possible Applications for Iseki Redivac’s Vacuum Technology
Rural community sewerage schemes
Industrial developments
Supply bases
Housing developments / compounds
Hazardous waste collection
Airports & military installations
Beach developments
Remote villages
Roof Drainage

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Outside view of Nadarzyn Vacuum Station

630 mᶾ/hr Vacuum Pumps inside Nadarzyn Vacuum Station

Fabrication of sewer junction

Installation underway in narrow trenches. Cost effec-tive solutions to many difficult drainage problems

Iseki Redivac Interface Valve installed in chamber

12th June 2018 by Iseki Iseki

GOREFIELD England

Client: Anglian Water
Country: England
Length of Pipe: 5000 m
No. of Valves: 105
Volume of Flow: 15 litres/second
Specialist Feature: Vacuum technology selected based on cost-efficiency and reliability over alternative systems.

Gorefield, located near Wisbech, is a beautiful village in East Anglia within the operational area of Anglian Water Services. The benefits of using vacuum technology to serve this village were identified by Anglian Water, after consultation with Barhale Construction and Iseki Redivac.

The system, designed by Iseki Redivac, was installed by Barhale Construction using unique techniques which had been developed especially for these projects with Iseki providing technical assistance and supervision. The two vacuum stations were constructed on vacant land at the edge of each village. This project has also seen the introduction of the very latest in Iseki Redivac’s process and control equipment including a computer-aided Individual Valve Monitoring and Analysis System. This has further enhanced the operational maintainability of these vacuum systems and has underpinned Iseki Redivac’s existing reputation for reliability and efficiency.

Completed in August 2003, the residents of Gorefield are now served by a state of the art sewer system which greatly reduces any potential impact on the environment. The installations, comprising of 5000m of polyethylene sewers and 105 vacuum interface valves, were completed with very little inconvenience to the residents and minimum disruption to local road traffic and businesses.

Vacuum Pipework
Vacuum sewers in polyethylene sized from Ø90mm to 200mm.

Vacuum Station Equipment
The vacuum station operates with two rotary vane vacuum pumps rated at 630m³/hr.

The sewage discharge pumps installed in the Gorefield vacuum station are centrifugal screw type pumps rated at 17l/s supplied by Hidrostal Ltd.

Summary
Poor ground conditions, challenging topography, river crossings and the need for installation to take place over a short time span, causing minimal impact to the normal life of the village, made Iseki Redivac the only realistic choice.

Applications for Iseki Redivac’s technology
Rural community sewerage systems
Industrial developments
Supply bases
Housing development/compounds
Hazardous waste collection
Airports & military installations
Beach developments
Remote villages

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Preparing the trench for the vacuum main to be laid

Iseki Redivac Interface Valve installed in chamber

630mᶾ/hr Vacuum Pumps Installed

12th June 2018 by Iseki Iseki

FOUCHERES, France

Client: La Commune Foucheres
Country: France
Length of Pipe: 5500 m
No. of Valves: 76
Volume of Flow: 5 litres / second
Specialist Feature: River and rail crossings

The village of Foucheres is situated approximately 150km South East of Paris near the town of Troyes. The village was served by septic tanks which overflowed at times when the water table was high. Collection of sewage using a conventional gravity system was difficult due to the ground conditions. The River Seine and the local railway line also had to be negotiated several times, which further added to the difficulty of installing a sewerage system. Using vacuum technology these problems were overcome by shallow digging and fixing small diameter pipes to the bridge.

As illustrated on the below photograph the vacuum pipe was fixed to the bridge decking. To achieve the required pipe invert levels over the bridge a lift of 1 metre was installed over a distance of 20m leading up to the bridge. The vacuum sewer pipe then falls towards the vacuum station which can be seen behind the trees on the left.

Foucheres

Vacuum Pipework
Vacuum sewers in polyethylene sized from Ø90mm to 160mm.

Vacuum Station Equipment
Two rotary vane air cooled vacuum pumps with a capacity of 160m³/hr.

Two dry well discharge pumps rated at 5l/s, duty and standby.

Vacuum vessel has a 4m³ volume and is epoxy coated inside and out and tested to Lloyds Certification.

The motor control cabinet is fully automatic with a programmable PLC. All pumps start in rotation.

The valve monitoring system which monitors the open/closed mode of each interface valve located around the village, can be individually observed from the vacuum station.

Exhaust gases are filtered by passing them through a Biological Filtration Unit situated adjacent to the vacuum station.

Summary
The Vacuum Way was able to offer substantial savings in cost together with a rapid and manageable installation due to the shallow, narrow trenches inherent with this technology.

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Vacuum Sewer being installed alongside other services

Valve Chamber Installed

Vacuum Vessel and associated equipment

12th June 2018 by Iseki Iseki

DUNAVARSÁNY 6 Villages, HUNGARY

Client: Pest County
Country: Hungary
Length of Pipe: 100km
No. of Valves: 2000
Volume of Flow: 7 Stations, 6000 Houses
Specialist Feature: Systems linked to common treatment plant. River crossings.

The six villages of Taksony, Szigetszentmarton, Majoshaza, Dunavarsany, Delegyhaza and Aporka comprise in total around 6,000 houses. The villages lie in Pest County, to the south of the Hungarian capital of Budapest. Until 1997 the villages were without mains drainage and the Pest County Municipality perceived this situation as in need of attention. Local consulting engineers examined many options in order to achieve the most cost effective and technically appropriate solution. After much consideration, a central sewage treatment works with vacuum sewerage collection systems was selected. The treatment plant is located between Dunavarsany and Aporka – approximately centrally within the group of villages. The six villages themselves are served by vacuum sewerage systems with the Dunavarsany village requiring two vacuum collection stations. In excess of 100 km of vacuum sewer mains and 30 km of pumped discharge mains are incorporated within the systems.

The work is being carried out by local contractor Resonator with the treatment plant due for commissioning in 1998 together with the collection systems for Taksony, Dunavarsany, Delegyhaza and Szigszentmarton.

Dunavarsany

Vacuum Pipework
Vacuum sewers in PN6 polyethylene sizes from 90mm – 200mm diameter with electrofusion joints.

Vacuum Station Equipment (each)
Each of the stations incorporates 3 No. liquid ring vacuum pumps rated according to peak flow within the catchment (Nash).

Two dry well discharge pumps rated according to peak flow (full duty).

Vacuum collection vessel fully protected for local conditions. Motor control cabinet fully automatic with a PLC. All pumps start in rotation and conditions are monitored with a data logging system.

Summary
This sewerage system could only have been designed and built within the allocated time span using ‘The Vacuum Way’ An achievement we are proud to be a part of.

Possible Applications of the Vacuum Way
Rural community sewerage schemes
Industrial developments
Supply bases
Housing developments / compounds
Hazardous waste collection
Airports & military installations
Beach developments
Remote villages

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Villages situated 5km south of Budapest.

Pre-cast concrete Collection Pit.

12th June 2018 by Iseki Iseki

DEERING, ALASKA, USA

Village Safe Water, Alaska

Client: Village Safe Water, Alaska
Country: ALASKA, USA
Length of Pipe: 1.68 km
No. of Valves: 53
Volume of Flow: 8 litres / second
Specialist Feature: Operation in arctic conditions

Deering is situated 800km North West of Anchorage. This small village consisting of some fifty houses, a school and a laundry sits on a narrow peninsular with the sea on one side and a small river estuary on the other. There are no roads leading to or from Deering so approach to the village has to be made by sea or air. A vacuum system was chosen to serve this village because of its versatility, ease of installation and its ability to transport the relatively low flows of sewage from the individual properties at high speed through small bore pipes to the vacuum collection station without the danger of the sewage freezing. The foam insulated polyethylene pipes were installed just above the permafrost. Glycol trace heating was installed to the foam, this is designed to stop the pipes freezing during the winter months when the temperatures can get as low as minus 50°C.

The electric supply to the village is provided by a small generator, so a new generator dedicated to supplying the power required by the vacuum system was also provided. The installation of the system commenced in 1997, however, work quickly came to a stop when the civil contractor uncovered the remains of an old village, many artefacts were discovered some inches below the surface during the excavation of the pipe trench. A team of archaeologists quickly set up a laboratory in Deering to examine and preserve the artefacts. This was a very slow process which resulted in no further pipe work being installed that year. In 1998 work recommenced but once again progress was slow.

Vacuum Pipework
Over 1500m of Polyethylene pipe were installed. Pipe sizes ranging from Ø90mm to Ø160mm.

Summary
As a result of the vacuum system being installed the residents of Deering can now take their drinking water from the river without the danger of it being contaminated by sewage which was previously disposed of by hand into the sea around the estuary.

Possible Applications of Iseki Redivac’s Vacuum Technology
Rural community sewerage schemes
Industrial developments
Supply bases
Housing developments / compounds
Hazardous waste collection
Airports & military installations
Beach developments
Remote villages

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Deering Main road

Vacuum Station

Toilet with Iseki Vacuum Valve installed in sump

12th June 2018 by Iseki Iseki

Zayed Sports City Stadium, UAE

Client: Abu Dhabi Municipality
Country: United Arab Emirates
Length of Pipe: 300 m
No. of Valves: 36
Volume of Flow: 50 litres/second
Specialist Feature: Collects sewage from 70,000 seat stadium

Situated in the heart of Abu Dhabi the Capital City of the U.A.E. is the prestigious Zayed Sports City Stadium, the venue of international sporting events and competitions. Guided by the belief of H.H. Shaikh Khalifa Bin Zayed, the Crown Prince in 1974 the complex was completed by 1980 and has a seating capacity of 70,000 spectators.

The Stadium plumbing and waste water collection system lies deep within the structure and finds its way into a gravity collector sewer constructed in a gallery around the perimeter of the stadium, at depths exceeding 4 metres.

Located in saline water conditions with an upper surface just below the ground level, the prospects of relaying the sewer in such ground conditions was a daunting if not impossible task. An alternative consideration to reline the damaged pipes was also very difficult primarily due to severe access problems.

Iseki offered the vacuum technology as a solution. The proposal was to intercept the incoming gravity flows above ground in collection sumps and via a vacuum interface valve and ring main collect the sewage in a steel vessel located in the vacuum station cleverly positioned beneath the seating.

Careful design ensured comprehensive operation of the system both under maximum design conditions of 70,000 spectators attending the 1994 Arab Gulf Football Tournament and normal day to day attendance with the very small flows generated by the employees at the complex.

The system whilst being fully automatic is monitored via telemetry in the Town Drainage central control complex thus alleviating maintenance costs but ensuring efficient and continuous working. With the installation now totally above ground future inspections or replacements will be particularly straight forward and cost-effective.

Vacuum Pipework
200 mm diameter polyethylene pipework around the service gallery connecting into the vacuum station

Vacuum Station Equipment
3 No rotary vane vacuum pumps each rated at 400m³/hr

2 No dry well discharge pumps each rated at 50 l/sec duty assist

Vacuum collection vessel volume – 16 m³ fully protected with epoxy coating and tested to Lloyds certification

Motor control cabinet – fully automatic with switchable programmable PLC. All pumps start in rotation and all conditions are remotely monitored via station telemetry in the Town Drainage dept central control which minimises personnel attendance.

Bespoke valve monitoring system which monitors the open / closed mode of each interface valve located around the stadium, the data is transmitted onward to central control such that each point of discharge within the Stadium can be individually observed.

Exhaust gases are filtered by passing them through an activated carbon filtration unit and are finally discharged via a vent stack to the rear of the stadium.

Summary
This project demonstrates the unique versatility and Engineering flexibility of the technology in providing solutions to difficult drainage problems.

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Stadium

Interface valve mounted in wall cabinet.

Collection Sump

Discharge pump and pipework

Black PE Vacuum pipe visible in roof prior to cladding

12th June 2018 by Iseki Iseki

All England Lawn Tennis Club, Number 1 Court, Wimbledon

Client: All England Lawn Tennis Club
Country: UK
Length of Pipe: 600 m
No. of Valves: 54
Volume of Flow: 120 litres/sec
Specialist Feature: Roof rainwater drainage. Large invert lifts from gutter to vacuum ring main.

As part of an on-going development of the excellent facilities at Wimbledon, the All England Lawn Tennis Club commissioned the design and construction of a new Number 1 Court. The chosen design included a symmetrical cantilevered roof with no supporting columns within the seating area, thus ensuring that all spectators will be able to enjoy unobstructed views of the tennis. However, this aesthetically pleasing design led to the problem of draining the stormwater since it was not desirable to have downpipes from the high-level gutter to ground level.

Following on from the success of the Centre Court drainage system the designers looked to Iseki to construct a new Roof Drainage system for the new Number 1 court. The Vacuum Way proved an ideal choice, with the interface valves located high in the roof space, draining both the inner and outer gutters via dual ring mains back to a single collection station, together with the system’s ability to cope with a full range of rainfall conditions.

The Interface Valves open and close automatically as the flow dictates and are switched off during play on the court, thus ensuring complete silence for the players. The complete system is constantly scrutinised via an Iseki valve monitoring system to check that valves and equipment are working fully and efficiently during the championships and automatically for the rest of the year.

No. 1 Court under construction

Vacuum ring mains

Vacuum Pipework
Vacuum sewers in polyethylene, sized from 90mm to 200mm diameter, with electro-fusion joints.Vacuum Station Equipment
3 liquid ring vacuum pumps each rated at 925 m³/hr duty/assist/assist (Nash) 3 No dry well discharge pumps each rated at 60 l/sec duty/assist/assist (Sihi) 25m³ Vacuum collection vessel fully protected and tested to Lloyds certification Motor control cabinet – fully automatic with programmable PLC. All pumps start in rotation and all conditions are remotely monitored via building management system to a central control office, which minimises personnel attendance. Bespoke valve monitoring system which monitors the open / closed mode of each interface valve located around the roof, such that each valve within the roof area can be individually observed from the collection station. This data is also passed through to the control office. Exhaust gases from this system are exhausted to atmosphere under the stands, whilst the water is discharged via a pressure main to the storm water drain in the road outside.

Summary
This project demonstrates the versatility of The Vacuum Way in its use for collecting effluents other than sewage. This roof had the difficult geometry of the gutter being some metres below the crown of the roof, which was where the main drainage pipes had to run for aesthetic reasons. This meant that a powered system of some kind had to be used and Iseki were able to offer the most cost effective and efficient solution.Possible Applications of the Vacuum WayRural community sewerage schemes Industrial developments Supply bases Housing developments / compounds Hazardous waste collection
Airports & military installations Beach developments Remote villages

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Vacuum Interface Valve suspended in roof

Valve Monitoring panel located in pumping station

Vacuum ring mains

Vacuum Ring Main suspended from roof structure

Narrow Streets unsuitable for conventional gravity sewerage system

12th June 2018 by Iseki Iseki

TAI WAI & TAI PO, Hong Kong

Client: Government of Hong Kong
Country: Hong Kong
No. of Vacuum stations: 2
No. of Valves: 110
Volume of Flow: 40 litres/second
Specialist Feature: Vacuum sewers installed in narrow streets that restricted access.

When the villages of Tai Wai and Tai Po in the New Territories of Hong Kong urgently required a replacement for their old septic tanks with a proper sewer system they were faced with a serious problem. They needed a completely new sewerage network, but the very narrow streets would not allow for trench digging machinery and conventional large bore sewage pipes simply could not facilitate the complexity of pipe runs required. Therefore a conventional gravity system could not be used. Iseki Redivac provided the answer. The Iseki Redivac technology only requires shallow narrow trenches to be dug enabling the connection of approximately 400 buildings. Connection to some of the more remote properties was a challenge to the designers and construction teams with each property seeming to present more obstacles and needing tighter connections. The principle of the system is that when sufficient effluent has entered the valve chamber it ‘triggers’ an Iseki Redivac interface valve which introduces vacuum to the chamber drawing the effluent into the sewer pipe at velocities of around 6 meters/second. At this speed, the sewers can accommodate tight bends, curves and even inclines whilst providing a self-cleaning, low maintenance system.

Vacuum Pipework
Vacuum sewers in PN10 polyethylene pipe sized from Ø90mm to Ø160mm with electro-fusion joints.

Vacuum Station Equipment
Two vacuum stations each operate with two rotary vane vacuum pumps. The two sets of pumps in Tai Wai and Tai Po stations are rated at 630 m³/hr and 250m³/hr respectively.
The sewage discharge pumps installed are centrifugal screw type pumps supplied by Hidrostal. Both vacuum vessels are fully coated inside and out as well as being certified to Lloyd’s standards. The motor control centre is fully automatic with PLC logic control. All pumps start in rotation and all conditions are monitored with a data logging system.

Summary
For Tai Wai vacuum technology was the only option available to the designers, as the trenches had to be dug by hand. At Tai Po the substantially lower installation costs and the need for fewer pumping stations made the Iseki Redivac system the preferred choice based on cost efficiency alone. The two sewer systems were installed over ten years ago and are still providing a reliable efficient service to the community.

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Narrow Streets unsuitable for conventional gravity sewerage system

Narrow Passageways

Interface Valve in bespoke chamber

Vacuum Vessel being installed

8th June 2018 by Iseki Iseki

UNIVERSITY CITY, Sharjah, UAE

Client: Sharjah Municipality
Country: United Arab Emirates
Length of Pipe: 44 km
No. of Valves: 410
Volume of Flow: 4 stations each 50 litres/sec
Specialist Feature: Versatile system that was designed, built and commissioned in 6 months

The Sheikh perceived the need for a University in the Emirates and he personally took on the task of coordinating the project. However this created a tall order with a time scale such that when Iseki were invited to offer a solution only 20 weeks remained before the planned opening. This fast track approach rendered the use of a vacuum sewerage system a must. Iseki Engineers designed the scheme on site ahead of construction. The use of local suppliers in Sharjah enabled the HDPE pipe to be manufactured to the required quality and delivered to site, allowing pipe laying to proceed immediately. Local companies were also used to manufacture the large vacuum vessels, whilst the balance of equipment, such as pumps, was shipped out from Europe. A tall order, delivered on time with the versatility of Iseki personnel and technology.

Vacuum Pipework
Vacuum sewers in PN10 polyethylene sizes from Ø90mm – Ø200mm with electro-fusion joints

Vacuum Station Equipment
Four stations each operating with three rotary vane vacuum pumps each rated at 400m³/hr (Busch) together with two dry well discharge pumps each rated at 50 l/s (full duty)Vacuum collection vessel 25m³ fully protected for Middle East conditions and tested to Lloyds certification. Motor control cabinet fully automatic with a PLC. All pumps start in rotation and all conditions are monitored with a data logging system.

Bespoke vacuum interface valve monitoring system which monitors the open/close mode of each valve at all locations around the project.

Summary
This sewerage system could only have been designed and built within the allocated time span using ‘The Vacuum Way’ An achievement we are proud to be a part of.

Applications for Iseki Redivac’s Technology
Rural community sewerage schemes
Industrial developments
Supply bases
Housing developments / compounds
Hazardous waste collection
Airports & military installations
Beach developments
Remote villages

Download this Case Study as a pdf

University of Sharjah

Avenue

Vacuum Vessel

Electrical Control Panel situated in the Vacuum Station

Pipe laying in progress