The Avac train decanting system was designed for installation in long haul train “stabling” or maintenance yards, in order to provide safe and efficient decanting of raw sewage from regional and interstate trains that are equipped with on-board toilets.

The system uses vacuum to lift the sewage from the waste retention tanks located under all of this type of train carriage. The sewage waste is lifted, via flexible hose connections, into a rigid pipe network for horizontal transportation to a centralised vacuum sewage plantroom, from where it is discharged to the municipal sewer system, or alternatively to an on-site treatment plant.

The rigid pipe network can be in-ground or more often is at an elevated level, typically fixed to the overhead crane gantries that are typical over the “roads” on which the trains are elevated for servicing, including sewage decanting.

The system is fully automated and computer controlled for operator safety and efficiency, and includes visual status of train decanting progress, data logging and off course emergency shutdown facility at all decanting stations.

How does it work?



Moving large volumes of sewage from train on-board retention tanks for disposal is potentially dangerous for the operators performing the task, as well as the significant risk of polluting the local environment should something go astray. Avac has developed a computerized multiple step safe method of doing so, with the operators’ safety as a major priority.


The Avac system facilitates the decanting of all of the train on-board sewage retention tanks within a short period allowing for a fast turnaround, this ensuring that the decanting process is not hindering the rolling stock being returned to service quickly.

Environmental Protection

The Avac system uses vacuum to lift the waste from the train on-board retention tanks into a piping network used for the transport of the waste to a central area for ultimate disposal. This means that should the be a problem (eg leaking pipe joint etc), there will be NO exfiltration of waste into the environment, rather air will be pulled into the system, and the Avac computerized system will raise an alarm and send it to the designated recipients advising of the problem.

New Construction Or Retrofitting Of Existing

In addition to providing decanting facilities in new stabling yards, the Avac system enables the retrofitting of this safe and efficient system to existing facilities. The piping network, which transports the waste from each decanting point to a central area, is kept under negative pressure (partial vacuum) while the system is operating. This enables the piping to be either in the ground, or above ground, eg suspended overhead from a crane gantry…thus enabling quick and cost effective retrofitting of existing facilities.