The Grinder Pump Lift Station: Popularity vs. Practicality
Romtec Utilities routinely designs package lift stations for wastewater, storm water and industrial process water. These lift station designs can include grinder pumps, cutter pumps, chopper pumps, turbine pumps, positive displacement pumps and solids handling pumps. Often times, the pump type is determined by the application, that is the water type. For wastewater, a grinder pump lift station is commonly requested by customers, but is the grinder pump the best solution for a wastewater lift station?
“Grinder” is a term that is easily recognized in the pumping world. The grinder pump lift station is common to the residential market capable of servicing 1 to 25+ homes. Grinder pumps can either be centrifugal or positive displacement, using different mechanisms to grind and move the wastewater. Depending on the location and flow requirements, a grinder pump station might be the best choice for a residential wastewater lift station.
The grinder pump lift station is a solution for low flow and high head applications. A submersible grinder pump grinds all the wastewater as it enters the pump. The opening for these pumps is less than ½” in diameter. Because the opening is so small, the grinder pump must grind all the material into fine slurry containing no solids. This action allows the force main size to remain small without worry of blockages.
The major concern with a grinder pump station is that if a solid too large for the pump to grind gets into the system then it can cause problems for the pump. Grinder pumps cannot pass solids, so a grinder pump lift station has its limitations. Situations where large solids could get flushed or drained may require chopper pumps or cutter pumps. Grinder pumps, cutter pumps, and chopper pumps are all centrifugal pumps but all can’t be used in the same situations.
A lot of people believe that a cutter pump lift station or chopper pump lift station are the same as a grinder pump lift station. We’ve already discussed that grinder pump stations can only process slurry, but chopper pumps and cutter pumps can actually pass solids up to 3” in diameter. Cutters and choppers are both types of submersible pumps. Any solids or stringy materials that are present in the wet well are cut down to a size the pump can handle.
Chopper pumps and Cutter pumps can pump a much larger range of flow in gallons per minute (gpm) than the grinder pump, making these lift stations more versatile. Because chopper pumps and cutter pumps don’t have to thoroughly pulverize solids, they require less maintenance. Cutter pump lift stations and chopper pump lift stations are also more efficient and have a lower likelihood of clogging.
The term “grinder pump station” is well liked by the pumping world because the word “grind” seems to imply the complete breakdown of solids, but the truth is that grinder pumps have strict size limitations for solids handling. When considering lift station design for wastewater or industrial process water with solids-handling requirements, Romtec Utilities will often let the lift station requirements determine the pumps to be used.
Romtec Utilities designs lift stations with grinder pumps, cutter pumps, or chopper pumps to meet each customer’s wastewater lift station requirements. If we’re told to use a grinder pump, we have no problem specifying one, but keep in mind that there are other pump-types available that might be better suited to your project. If you have any questions, call the Romtec Utilities Sales Staff today and see if the grinder pump lift station is the best solution for your pumping problem.