Grinder pump
Encyclopedia
A grinder pump is a waste management
device. Waste from water-using household appliances (toilets, bathtubs, washing machine
s, etc.) flows through the home’s pipes into the grinder pump’s holding tank. Once the waste inside the tank reaches a specific level, the pump will turn on, grind the waste into a fine slurry, and pump it to the central sewer system
.
Grinder pumps can be installed in the basement or in the yard. If installed in the yard, the holding tank must be buried deep enough that the pump and sewage pipes are below the frost line
.
There are two types of grinder pumps, semi-positive displacement (SPD) and centrifugal.
, 1.5 hp
or 2 hp
. A cutting mechanism macerates waste and grinds items that are not normally found in sewage, but may get flushed down the toilet. The pump has a level sensor either built into the pump, called “sensing bells,” or attached externally to the pump, called “floats.” (The level sensing devices vary among grinder pump manufacturers.)
If the pump malfunctions and the waste level in the holding tank rises above a certain level, the alarm panel should alert the homeowner that the pump is experiencing problems. The alarm panel should have both a buzzer and an indicator light.
The holding tank, likely constructed of fiberglass
, high-density polyethylene (HDPE) or fiberglass-reinforced polyester
(FRP), has an inlet opening and a discharge opening. The pipes from the home are connected to the inlet; the pipe that leads to the sewer main is connected to the discharge. Often, more than one home or restroom (in a park, for example) can be connected to one grinder pump station. In this case, more than one inlet can be installed. It is a good idea to consult the manufacturer or factory representative before purchasing a grinder pump station to ensure that more than one inlet hole can be drilled.
The tank has a lid made from heavy-duty plastic or metal that is bolted and/or padlocked shut to prevent entry by unauthorized persons.
Homeowners are not usually limited by what they can or can not pour down their drains because their home has a grinder pump. Sanitary napkins, diapers, kitty litter, paint, oil (both motor oil and cooking oils), etc. should not be flushed or poured down any drain, whether the home is connected to a gravity sewer system, septic tank
, grinder pump or cesspool.
A questionable item is "disposable wipes" that are made by cleaning companies for personal use, cleaning toilets, etc. Some wipe companies say "flush one at a time," some say "not for pump systems," some say "safe for sewers." Check with the grinder pump manufacturer for their recommendation.
In large sewage pump stations, clogging problems are often avoided by installing a chopper pump in the tank. A chopper pump is able to handle larger/tougher solids than a residential grinder pump, including hair balls, diapers, sanitary napkins, clothing, etc.
Waste management
Waste management is the collection, transport, processing or disposal,managing and monitoring of waste materials. The term usually relates to materials produced by human activity, and the process is generally undertaken to reduce their effect on health, the environment or aesthetics...
device. Waste from water-using household appliances (toilets, bathtubs, washing machine
Washing machine
A washing machine is a machine designed to wash laundry, such as clothing, towels and sheets...
s, etc.) flows through the home’s pipes into the grinder pump’s holding tank. Once the waste inside the tank reaches a specific level, the pump will turn on, grind the waste into a fine slurry, and pump it to the central sewer system
Sanitary sewer
A sanitary sewer is a separate underground carriage system specifically for transporting sewage from houses and commercial buildings to treatment or disposal. Sanitary sewers serving industrial areas also carry industrial wastewater...
.
Grinder pumps can be installed in the basement or in the yard. If installed in the yard, the holding tank must be buried deep enough that the pump and sewage pipes are below the frost line
Frost line
The frost line—also known as frost depth or freezing depth—is most commonly the depth to which the groundwater in soil is expected to freeze. The frost depth depends on the climatic conditions of an area, the heat transfer properties of the soil and adjacent materials, and on nearby heat sources...
.
There are two types of grinder pumps, semi-positive displacement (SPD) and centrifugal.
Components
The grinder pump “station” consists of the pump, a tank, and an alarm panel. A pump for household use is usually 1 hpHorsepower
Horsepower is the name of several units of measurement of power. The most common definitions equal between 735.5 and 750 watts.Horsepower was originally defined to compare the output of steam engines with the power of draft horses in continuous operation. The unit was widely adopted to measure the...
, 1.5 hp
Horsepower
Horsepower is the name of several units of measurement of power. The most common definitions equal between 735.5 and 750 watts.Horsepower was originally defined to compare the output of steam engines with the power of draft horses in continuous operation. The unit was widely adopted to measure the...
or 2 hp
Horsepower
Horsepower is the name of several units of measurement of power. The most common definitions equal between 735.5 and 750 watts.Horsepower was originally defined to compare the output of steam engines with the power of draft horses in continuous operation. The unit was widely adopted to measure the...
. A cutting mechanism macerates waste and grinds items that are not normally found in sewage, but may get flushed down the toilet. The pump has a level sensor either built into the pump, called “sensing bells,” or attached externally to the pump, called “floats.” (The level sensing devices vary among grinder pump manufacturers.)
If the pump malfunctions and the waste level in the holding tank rises above a certain level, the alarm panel should alert the homeowner that the pump is experiencing problems. The alarm panel should have both a buzzer and an indicator light.
The holding tank, likely constructed of fiberglass
Fiberglass
Glass fiber is a material consisting of numerous extremely fine fibers of glass.Glassmakers throughout history have experimented with glass fibers, but mass manufacture of glass fiber was only made possible with the invention of finer machine tooling...
, high-density polyethylene (HDPE) or fiberglass-reinforced polyester
Polyester
Polyester is a category of polymers which contain the ester functional group in their main chain. Although there are many polyesters, the term "polyester" as a specific material most commonly refers to polyethylene terephthalate...
(FRP), has an inlet opening and a discharge opening. The pipes from the home are connected to the inlet; the pipe that leads to the sewer main is connected to the discharge. Often, more than one home or restroom (in a park, for example) can be connected to one grinder pump station. In this case, more than one inlet can be installed. It is a good idea to consult the manufacturer or factory representative before purchasing a grinder pump station to ensure that more than one inlet hole can be drilled.
The tank has a lid made from heavy-duty plastic or metal that is bolted and/or padlocked shut to prevent entry by unauthorized persons.
Maintenance
Grinder pumps should not require preventive maintenance. However, grinder pumps that use floats to sense the level in the holding tank are prone to grease buildup that may turn the pump on unnecessarily, or not turn on the pump at all, causing the tank to fill up and sewage to possibly back up into the home or yard. To prevent this, grinder pumps that use floats are often hosed down to remove the grease from the floats.Homeowners are not usually limited by what they can or can not pour down their drains because their home has a grinder pump. Sanitary napkins, diapers, kitty litter, paint, oil (both motor oil and cooking oils), etc. should not be flushed or poured down any drain, whether the home is connected to a gravity sewer system, septic tank
Septic tank
A septic tank is a key component of the septic system, a small-scale sewage treatment system common in areas with no connection to main sewage pipes provided by local governments or private corporations...
, grinder pump or cesspool.
A questionable item is "disposable wipes" that are made by cleaning companies for personal use, cleaning toilets, etc. Some wipe companies say "flush one at a time," some say "not for pump systems," some say "safe for sewers." Check with the grinder pump manufacturer for their recommendation.
In large sewage pump stations, clogging problems are often avoided by installing a chopper pump in the tank. A chopper pump is able to handle larger/tougher solids than a residential grinder pump, including hair balls, diapers, sanitary napkins, clothing, etc.