A lift station is essentially a waste management system. This is used when drain lines located under the sewage line or any plumbing fixtures on a structure produce waste.
The idea of a lift station is to push the sewage high enough so that it can reach the main sewage line following which gravity will carry it out of the plumbing system and into the main system which is typically the municipal drainage system. Hence the name “lift” station.
Now, there is more than one type of lift station and the choice depends on where it needs to be used.
The municipality which collects and also treats drainage water uses two kinds of lift stations—wet well and dry well. The first is a more modern system and the second is the traditional choice.
Also called a submersible pump, a wet well is typically submerged in the drainage water that it is meant to pump upwards. It has a pump that is mounted on the inside of the wet well. A motor is used to get the wastewater to the required level so that gravity can finish the job.
This is a traditional choice and is often placed underground or in a separate chamber from the house. The distance makes it a challenge to maintain a dry well. It is also considered more dangerous than a wet well, its modern counterpart.
There are a few aspects to keep in mind when it comes to designing and constructing a lift station.
- Sewage water is a mix of many fluids and sometimes solids too. The debris can cause clogging, which means you will need a grinder-type pump.
- Wastewater also generates a lot of toxic gases, which means the lift station is a hazardous place.
- Pumps are prone to cycling quite often and too much of it is bad news. So, depending on how often it is switched on and off, it is wise to figure out if a lift station needs multiple pumps.
- The pump should not be switched off for so long that sewage starts becoming septic. If and when it does, it is a condition called putrefaction which is dangerous and must be tended to with special care.
- Most designs today are submersible. This solves a lot of problems that come from keeping the motor and pump away from the sewage system. This makes it a good choice for most structures.
Let’s take a wet well into account. These systems are made to store sewer water temporarily till they are collected by the municipal system. They come with:
- One receiving well
- One or more submersible pumps
- Pumps and their associated valves
- One valve vault
- One or more motors
- One control panel
- One backup generator
- Pump float controls
- Devices for radio communication
- Ventilation system
- Odor control
- Alarm system
Some of them also have a screener to get rid of coarse materials.
The wastewater is pumped upwards by the lift station using a force main which is a pressurized pipe. This sends the wastewater towards the point where it will be lifted to an elevated point.
These are basically the components of a functional lift station from the starting point, which is the power supply to the station, to ways of monitoring the content inside and the control that you need so that the process never fails.
All these parts are in enclosed structures which is why there is such emphasis on their design aspects. Lift stations can also be customized based on the needs of a specific structure.
For an effective sewage system, you need a lift station that functions well. And this is its role in keeping the system afloat.
Raw sewage first makes its way to the underground collection tank through pipelines that are tilted downwards. This is when gravity does the job which is also why they are called gravity pipelines.
Sometimes, waste needs to enter the collection system from pipes that are lower than the tank itself. That means you cannot count on gravity to do the job. When you don’t have the advantage of gravity, you need a lift. That’s where the lift station comes into play.
When the sewage reaches the collection container, it does so with the help of an elevation that is part of the lift station. This is basically what a wet wall is for. It has a holding cell that collects the sewage and then tests the wastewater.
The levels are then monitored with the devices placed in it and solid materials in that waste are removed using a grinder or screener. When this holding cell gets filled, the pump will push the sewage upwards with the help of a pressurized pipe also called the force main.
The force main contains compressors and pumps that make the elevation of the wastewater possible. This gives it the push it needs, quite literally, into the collection tank where it will be treated and sent to the municipal sewage treatment plant.
There will inevitably be problems with every plumbing system at some point. When that happens with a lift station, it might be because there is a power outage or a break in the force main or the pump has failed.
As a result, the wet well will get filled beyond its capacity. The wastewater then finds its way back into the collection system, which can either flood the wet well or worse, lead the sewage water back into the house.
Clogging is also not an uncommon problem in lift stations because of the type of materials that make their way into the tank. This is most likely due to FOG or fats, oils and greases.
In business structures like restaurants, extra precautions are taken to deal with this kind of waste materials. They install flushable rags of some sort, which keep the system operating smoothly.
Bad smells are also an expected problem with lift stations and this can be a problem for your neighbors. These gases are also extremely corrosive and can cause structural damage to the pumps, piping and the wet wall itself.
Whether you have a single pump system or a multiple pump system, you want to make sure that there are no design discrepancies, and that the unit is maintained properly from time to time so that there isn’t an explosion of sewage water on your property.