H.I.Fraser have experience in supporting a number of municipal vacuum sewage systems varying from hotels retrofitted in to historic finger wharves, through to large housing estates built on ground with high water table and even industrial estates built on reclaimed land at port facilities.
We provide maintenance services for the existing systems installed by third parties as well as through-life support of the systems engineered and installed by our team based on Iseki Redivac’s municipal vacuum sewage technology.
Our long-term partner Iseki Redivac have 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 a complete range of services for system review, assessment and maintenance as well as supply all the specialist products and spare parts required to maintain a municipal vacuum sewer system. With extensive stock in our Perth and Sydney facilities and technicians available to help on site, we are able to provide premium service for a competitive price.
Examples of the projects we have been working on include:
- Refurbishment of buildings and housing re-developments
- Refurbishment of buildings in river, lake and coastal communities
- Stadium roof collection upgrades
- Long buildings, wharves upgrades
- Retrofit of sewage to old communities which are un-sewered or have deficient gravity sewer systems.
How an Iseki Redivac municipal vacuum sewage system works:
Waste water is discharged from a building or facility via gravity and directed in to 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 in to 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 gravity drains 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: