A pressure sewer system consists of a series of positive displacement grinder pumps moving finely ground effluent material along a network of small diameter polyethylene pipes. Each dwelling within the system has a below ground pump station. The waste water is delivered to the station by traditional gravity methods; this is then ground into a fine slurry and pumped under a low pressure through a network of polyethylene pipes. The piping network can extend for many thousands of metres at a total dynamic head of 60 metres.

Gravity Sewer 
Pipelines are laid on a grade to pumping stations or large diameter trunk sewer mains.
Minimum pipeline grades must be achieved to ensure that the wastewater velocities are sufficient that solids
don’t settle and odours don’t occur, thus meaning deep trenches, harder environmental impact and sometimes not economically viable when terrain becomes difficult.

Pressure Sewer System 
Each property is provided with a small pump station unit, the property drain is connected to this pump unit and all
wastewater from the property is pumped under a low pressure to a discharge point, which could be an existing gravity sewer or treatment plant. Due to the velocities of pressure sewer smaller pipe sizes are used and only a minimum cover over the pipeline is required. Pressure sewer does not require pipeline grades unlike gravity.

Typically pressure sewer systems are installed where traditional gravity methods are not used due to the cost of installation and poor ground conditions. Areas that have been served by pressure sewer are hilly mountainous terrains, coastal flats with very high water tables, areas of extreme environmental & cultural sensitivity, parks and city suburbs where the gravity point is higher than the dwelling. Pressure sewer technology is currently being used by the major metropolitan water authorities, rural water authorities & councils, land developers and individuals who require a reliable pumped sewer system.

In all cases pressure sewer can be adapted to suit each individual case. There is a diverse range of products available in Australia like; different size stations, multiple pump configurations and custom made systems to suit individual needs. Pressure sewer can operate as a stand alone system or it can be integrated into rising mains, waste water treatment plants or gravity sewers.

Pump stations are usually installed in a location that the property owner agrees to, and along with the pump station there is a small control panel which can be mounted on a dwelling or remotely on a post. A colour maybe specified for the control panel to suit environmental features and location. The pump station protrudes from the ground by only 100mm in height and 1 meter in diameter and has a typical green lid to suit gardens, lawn area’s and native vegetation.

A separate circuit from the properties existing switchboard needs to be installed, and that circuit needs to run to the control panel location within the property.

All pressure sewer pump stations are size to have a storage capacity but during times of power failure the user needs to be mindful of their water usage until power is restored; protection against brown outs is an optional component of a pressure sewer system and can be easily installed to protect the pump against this type of occurrence.

Pump operation is dependant on waste water production from the dwelling; during peak times typically the pump will start more frequently between 5 and 10 times daily in an average property with a run time of 1 to 3 minutes per cycle.

The pump station is fitted with tamper proof bolts to control access into the pump chamber area and the control panels are fitted with either padlocks or internal locks.

The pump stations are very quiet, the pump that pumps the wastewater is located at the bottom of the pump station (wet well) which is around 1metre below surface level, the pump stations are vented thru the property drain and thru the pump station lid which helps dissipate the build up of odours inside the pump chamber, also due to the frequency of pump run time wastewater is not held very long inside the pump well before it is pumped away.

The pump stations are very small and the complete installation on property should take around 2 days to complete. The pressure sewer reticulation is typically installed via trenchless techniques and with smaller diameter pipes, the construction time frame is far more efficient that typical gravity sewer.