What is a Foul Pump Station?
Foul pump stations move wastewater from A to B in low gravity areas and are also known as lift stations. Wastewater flows downhill, but what happens if it needs to get back up to higher ground? This is where a foul pump station comes in – to give it a push to get there!
A typical foul pump station consists of a tank with an inlet, an outlet and one or more pumps inside that use electricity. When sewage enters the pump station and reaches a certain level, a float switch activates the pump. The pump then propels the wastewater to next point of call such as a sewer or a treatment plant.
Large wastewater pump stations include a control panel to allow for manual operation during maintenance work or repairs. During normal conditions, pumping stations operate on a single pump or set of pumps but will have back up pumps ready to take over in case a pump fails. This is known as built in redundancy.
Pumping stations are the most effective way to move wastewater. The size of the pump station and power of the pumps will depend on the volume and the type of wastewater to be pumped, so let’s take a look at at some different types.
Traditional Pump Stations
Older pump stations often consist of a wet well and a separate, adjacent dry well which houses the pumps. The wet well is the holding place for wastewater that flows via gravity and is hooked up to the pumps inside the dry well. Dry well pumping stations are no longer a popular option for two reasons:
- Confined underground space access – making maintenance and repair work tricky and hazardous
- Flooding risk – leaky pipework or pump failure can flood the dry well with sewage and cause expensive damage
It’s for this reason that wet well pump stations and wet wells with integrated pumps have come to replace traditional dry well pump stations. The pumps inside a wet well are known as submersible pumps and we’ll discuss these in the next section.
As the name suggests, submersible pumps are submerged in wastewater. The motor in a submersible pump is carefully sealed to prevent any liquid from entering it and causing it to fail. Submersible pumps can be lifted to ground level using a chain and guide rail system which is much safer and easier than accessing pumps in a dry well for maintenance and repairs. Foul pump stations with submersible pumps operate across a huge variety of applications from domestic and light commercial to municipal and industrial. See below for the typical operational ranges of submersible pumps:
- Flow rate ranges between 20 to 28000 lpm
- Horsepower ranges between 1 to 250 hp
- Total head (pressure) ranges between 0.4 to 6 Bar
In some applications, it may be necessary for the foul pump station to be capable of handling solids. A grinder pump, typically used in domestic sewage pumping applications, will reduce solids in the wastewater to create a fine slurry which it will then pump to a septic tank or a sewer. In residential areas, one grinder pump station may serve multiple houses.
Packaged Pump Stations
A packaged pump station is a self contained system with all the internal pipework fitted inside a watertight, reinforced tank. After the tank is installed below ground, the submersible pump and control equipment are fitted and connected to the power supply. Once the inlet and outlet pipes are connected to the pump station it is ready to operate. Packaged foul pump stations are a very popular choice due to the ease of installation, access and maintenance. A reputable wastewater treatment company will often include service checks as part of the package.
Pumping up to thousands of litres of wastewater and sewage on a daily basis will inevitably cause internal wear and tear. That’s why controls and alarms are essential equipment for foul pump stations. When the wastewater rises above a certain level an alarm will notify of a failure in the system. Suppliers may even offer a remote monitoring service with SCADA, the Supervisory Control & Data Acquisition system. This is particularly helpful with large foul pump stations that need close supervision and regular checks.
Do I Need Sewage Pump Station?
Foul pump stations are an essential part of wastewater treatment. Without pump stations, wastewater accumulates in low gravity areas, backs up pipes, overflows into buildings and floods land. Even if you weren’t aware of it, or unless you live on the top of a hill, there is probably a pump station close by! If you are building a new home and think you may need a foul pump station, get in touch with a local wastewater treatment company, they will advise you best. The same is true for commercial premises.