What is a Sewage Pump?
Most sewage systems work using the power of gravity to move solids and liquids down a line. There may be situations where it is simply not possible to put plumbing devices uphill from a septic or city sewage system, however, and in those cases, a sewage pump becomes an indispensable item to move effluent. This type of pump has one job and one job only: to move solids and liquids between locations. A typical one will sit in a sewage basin, which must naturally be in the lowest area of the location needing drained. The pump is capable of being submerged and will likely have to deal with some fluids at nearly all times.
A submersible sewage pump is located at the bottom of basin or receptacle, such as a septic tank. The intake for that pump is located as close to the floor of the basin as possible, often being found on the bottom or near the bottom of the device. The goal is to empty as much of the solids and liquids as possible out of the basin. Because some room must be left between the floor and the pump, however, it is unlikely that total draining will ever take place without manual intervention.
While this pump will mainly handle liquids, there will be times when solids will also need disposed of though a system. Most pumps are capable of handling solids up to 2 inches (5 cm) in diameter. Commercial pumps may be capable of handling even larger items.
The vast majority of sewage pumps work the same way. A bulb is attached to the pump much the same way it may look on a sump pump or even in a toilet reservoir. When that bulb reaches a certain height, it kicks on a switch, starting the pumping action. When the liquids lower the bulb to a certain point, the pump switches off.
The main point for many residential consumers is determining what size of a pump to buy. They are usually rated in horsepower, and most are between 0.5 hp and 1 hp. The size of the pump should be based on the amount of sewage generally needing to be transported, usually expressed in gallons per hour. Generally, household sewage pumps are capable of moving between 5,500 gallons (20,000 liters) and 8,000 gallons (about 30,000 liters) per hour. The cost typically depends on the horsepower rating.
Only homes that are not connected to a city sewer system have septic tanks. Most septic tanks work by gravity to send clear water to the drainage or leach field. However, if the field is higher than the septic tank, an effluent pump is used.
Septic tanks should be pumped out by a service company with a pump truck every 3 years or so. This will help maintain both your pump and your field. However pumps, like any appliance, have a limited life span and will need to be replaced every every 2-10 years, depending on the quality.
Even homes on city sewer can have a sewage pump. These might be needed to pump sewage from basement fixtures up to the main house sewer line. Or if your household sewer line is below the level of the city main line, you will need to pump your sewage up to their line.
Sump pumps are used to pump ground water out of your crawlspace or basement.
I've always wondered why the water treatment plant in my town is so far away from the city limits, but it's probably because of being able to use gravity for moving waste water. Most of the town is on a hill, and it was probably more expensive to use sewage pumps than just install extra pipelines out of town.
Do rainwater and sewage water all mix together underneath a city? I remember a couple of years ago there was an issue where the city had to install a new, bigger sewage pump station because after heavy rains certain streets would flood.
If you live in a rural home, is there any type of sewage pump maintenance you can perform to keep it functioning properly?
I don't know anything about septic systems or sewage flow, but 5500 to 8000 gallons per hour seems like a pretty extreme amount. It seems to me that even if you were doing laundry, running the shower, turning on the faucets, and flushing the toilet all at the same time, you would have a hard time using that much water. Do they ever reach this maximum?
Is there any real difference between a sewage pump and a sump pump besides the fact that a sewage pump is designed for solids?
@kentuckycat - You are right. Septic tanks are primarily used for homes or businesses that do not have access to a local sewer system. If you live in town, you are probably not personally responsible for a sewage pump, but your waste may pass through one at some point.
Basically, a septic tank works by filtering out waste water from a home and then delivering it back into the yard as cleaner water. Solids naturally separate from the system and need to be pumped out and trucked away occasionally. I'm not sure if this process uses a sewage pump or not.
Like the article mentions, in town, sewage pumps would primarily be used to move waste from a lower area uphill toward the treatment plant.
Not everyone has a septic tank do they? I thought that these were mostly in rural areas where there were not regular city sewer lines. If that's the case, not everyone has a sewage pump, right? If I have one, I have never known about it.
I have never lived in the country or outside of a town, so I'm not sure exactly what a residential sewage pump is needed for. This article gives a good description of how it works, but if you live in one of these rural areas, to where does the sewage pump deliver the waste?
I guess my real question behind all of this is how does a septic tank work, or what is it's main function?
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