Gas Station Grinder Pump Helps Save Money

Oct. 10, 2019
Installation of a new grinder pump at an Indiana gas station leads to significant cost savings for municipality

In 1999, the town of St. Leon, Ind., voted to upgrade its decentralized septic systems to a municipally operated sewage system. Because of varying elevation levels throughout the town, a low-pressure sewage system was chosen. Today, the town processes more than 200,000 gal of sewage per day, and has more than 1,000 single-phase grinder pumps in operation.

The town’s property owners are required to purchase the grinder pumps for each site, and are responsible for maintenance should a clog or other issue occur. Most clogs stem from the flushing of products deemed “flushable” by manufacturers. Across the country, items such as paper towels, baby wipes and disposable cleaning cloths are overwhelming sewer systems and causing costly clogs and disruption in service. In St. Leon, these incidents typically are infrequent and easily corrected.

“Normally, clogging occurs with new residents who are unaware of what materials cannot be flushed into a grinder station,” said Steve Clark, plant operator for the St. Leon Wastewater Utility. “Once they have been informed, the problem goes away.”

Identifying the Problem

Not all of St. Leon’s clogging problems are always eliminated, however. A grinder pump located at a high-traffic gas station was experiencing frequent maintenance issues, requiring unclogging two to four times per month.

“People flush anything—baby wipes, diapers, feminine products, clothing—and when the bathroom runs out of toilet paper, paper towels would get flushed down too,” said Dave Deddens, owner of the gas station.

The gas station has also been expanding over the years, adding more amenities and a fast food restaurant, but the size of the grinder station remained the same, as the owner was hesitant to pay for an upgrade. This increase in use on the grinder pump put added stress on the system capacity, which had been maximized.

Frequent service calls were inconvenient and expensive for both Deddens and the municipality. Each service call costs Deddens $50, in addition to the inconvenience caused by the gas station being unable to use its water until the clog is cleared. But the cost to the municipality is significantly higher. To clear the clog, the municipality must employ a vacuum truck, which costs approximately $400 per service call. The municipality also is responsible for the cost of labor required to clear the clog, administrative costs associated with necessary paperwork and any additional repairs that might be needed further down the line.

Finding a Solution

To help eliminate these costly clogs and relieve the financial burden on the municipality, Clark contacted Straeffer Pump and Supply for a solution. Straeffer recommended the Myers V2 grinder for the difficult application.

The Myers V2 employs a semi-open impeller and patent-pending axial cutter technology, designed to cut through challenging solids and trash found in domestic wastewater without roping or clogging. Unlike radial cutters, which have open spaces that can easily clog, axial cutters take small bits out of solid material and push the remaining material away, preventing large masses from blocking the inlet and shutting down the pump.

The V2 operates like a pair of scissors. A stationary cutter plate has holes that allow fluid to flow through, while a rotating cutter moves with the motor shaft. As the blade of the rotating cutter passes over the inlet holes, it creates a scissor action that cuts the material passing through the stationary cutter.

Tim Bertram, vice president of Straeffer, explained that there are two types of clogs: one that strings up slowly, and one that occurs all at once with a single-phase pump during start/stop. When a radial cutter grinder, still in the process of grinding an object, shuts off after a pump cycle, it often clogs on restart because it lacks the torque to continue grinding the material. “I was convinced the V2 was the solution when I reviewed the product specs and saw the new design with improved torque,” Bertram said.

“What sold me on the new V2 grinder as a solution to St. Leon’s problem was the video demonstrating how well it grinds the material that clogs traditional grinders, especially during start/stop,” said Elisha Winters, branch manager of Straeffer.

To install the V2 in the existing grinder station, the team had to change the capacitor in the control panel, adjust the standpipes and check that the V2 was drawing the correct amps. Since installation in April 2015, the gas station has not experienced a single clog. When Deddens built a new restaurant adjacent to the gas station, he made sure to specify the V2 unit.

“During the construction of the new restaurant I had considered using hand dryers exclusively in the bathroom rather than paper towels because people will flush anything. I was afraid we were going to end up with paper towels clogging the new grinder station,” Deddens said. “The V2 grinder performed so well at our gas station that we decided to keep the paper towels, and insisted that our new grinder station for the restaurant be designed with the V2 grinder.”