H.I.Fraser has supplied a number of municipal vacuum sewerage systems to developments around Australia. Some of these have been operating for over 20 years.

These installations vary from hotels retrofitted into historic finger wharves,  through to large housing estates built on ground with a high water table and even industrial estates built on reclaimed land at port facilities.

Many of these installations would not have been possible without vacuum solutions as traditional trenching was not possible or was cost prohibitive or local conditions meant the consequences of sewerage leaks were too significant.

Vacuum systems supplied by H.I.Fraser replace gravity mains and transport waste water at high velocity in the vacuum piping high velocity air, so the  piping can be run in shallow trenches parallel to the ground surface or where necessary above ground. In fact it is possible to move sewage uphill and around obstacles giving great freedom for designers and builders.

Additional benefits of vacuum piping are:

  • smaller diameter piping
  • very low holding time in the piping
  • the piping is self-cleaning due to the high velocities of the waste water scouring the piping
  • there are no blockages caused by low gradient piping
  • in the event of cracked piping, the subsequent leak is only air from outside the pipe to inside – no contamination or health concerns.

Municipal vacuum sewage systems services H.I.Fraser provides in Australia

At H.I.Fraser, we provide design, product and maintenance services based on Iseki Redivac municipal vacuum sewage systems to the Australian market. Iseki Redivac has been providing these systems to customers around the world for over 25 years out of it’s Daventry facility and have an excellent reputation for service and quality.

We can provide system design, backed 100% by Iseki Redivac, system review, system maintenance and of course all the specialist products required to build a municipal vacuum system. We stock all the parts required to maintain a system in our Perth and Sydney facilities and have technicians available to help on site when needed.

We can also provide mixed vacuum systems, where we use water saving EVAC vacuum toilets within a building, these vacuum toilets have a 1.2 litre flush, and then utilise Iseki Redivac chambers and valves to collect all other gravity waste water. All of these products operate from the same vacuum plant and main line piping.

View our Case Studies to learn more about what we do

How an Iseki Redivac municipal vacuum sewerage system works:

Waste water is discharged from a building or facility via gravity and directed into a valve chamber. This chamber is usually around 2m in height and 1.2m in diameter. The bottom section of the chamber is shaped to form a small sump. This sump creates batches of waste water for transfer via the vacuum piping.

An Iseki Redivac vacuum interface valve is mounted in the top of the chamber and is fitted with a suction pipe dropping down into the sump. As the waste water rises in the sump, it triggers the valve to open to the vacuum sewer piping. The atmospheric air pressure acting on the waste water in the sump forces the water up suction pipe, through the valve and in to the piping . The valve stays open for 6-10 seconds after all of the waste water has emptied from the sump to allow air to enter the piping. This air mixes with the waste water batch creating a foaming mixture which travels down the piping at up to 6m/s. The valve then closes, completing the cycle.

As the foaming mixture travels down the pipe, the waste water slowly separates from the air and drops on to the walls of the pipe. This drains by gravity to the lowest point in the piping sawtooth, collects as a small pool and then is again transported down the piping via the next batch of air travelling down the pipe. Piping lengths of 3,000m are common. It is the total drop in vacuum pressure along the pipe that limits the piping length. Eventually the air and liquid reaches the vacuum plant room and enters the vacuum tank.

The vacuum plant comprises a tank usually manufactured in steel, vacuum pumps which can be liquid ring or dry vane type, sewage discharge pumps, a control panel and various pressure and level sensors in the tank. The vacuum tank stores both vacuum, to ensure peak loads are met without vacuum loss, and the waste water. The discharge pumps operate once the waste water reaches a pre-determined level and transfers the wastewater to a treatment plant or a nearby main sewer.

The following links provide videos and brochures on the operation of these vacuum systems:

The Iseki Redivac municipal vacuum sewerage system can be used for:

  • Housing developments
  • Stadium roof collection
  • Long buildings, wharves
  • River, lake and coastal communities
  • Refurbishment of buildings
  • Retrofit of sewerage to old communities which are un-sewered or have deficient gravity sewerage systems.