| With a population of 677, the small town of Harleyville, S.C., located 60 miles northwest of Charleston, was looking to upgrade its aging lift stations to increase efficiencies, lower utility costs and reduce overall pump maintenance for its municipal wastewater facility. |
Efficient Pumps Slash Run Times, Energy Use "Due to the greater pumping capacity of the Grundfos SLV pumps, the station's run time dropped by roughly 80 percent," said Dan Huggins, P.E., project manager, URS Corporation, who noted that peak pump operation fell from an average of 18 hours per day to 3.5 hours per day (factoring in median
rainfall and infiltration amounts). The additional pump capacity combined with the reliability of the SLV Series' pumps made an immediate impact on the trouble-plagued system. "Since
power consumption accounts for 85 percent of a pump's lifecycle costs, likely the most dramatic savings for this project is the ability to maximize pumping performance across each lift station," said Robert Pruit, principal of Carolina Pumpworks, who worked with Huggins to incorporate the SLV pumps. "Some of the town's outdated pumps were running nearly non-stop during increased flow events to keep the
wet wells from overflowing. For example, when rainfall swelled the volume of flow into the town's sewer lines, both of the pumps at each of the individual lift stations would typically run for extended periods of time to deal with the increased flow."
Added Capacity & Redundancy In all, the three newly upgraded duplex lift stations each feature two 5.5-HP, 1,750-RPM, three-phase pumps that alternate operation according to the station's level control system, which offers both system redundancy and added capacity during increased flow events. To overcome prior difficulties with pumps clogging, the team selected the optional SuperVortex impeller, to help ensure that solids up to 3-inches in diameter pass freely through the
solids-handling pump without jamming. Carolina Pumpworks also provided custom-designed control panels to meet Harleyville's requirements. The control panels included the Grundfos IO113 pump monitor relays that together with the pump sensors provide more protection against
thermal overload and seal leakage. The transformation began in October 2011 when -- with the aid of state grants -- the town installed its first SLV pump system at Pump Station 5 as a retrofit application. This aging lift station served 125 residents and pumps sewage one-quarter mile to the next
manhole and was plagued with service issues. "The old pumps frequently clogged, and the resulting motor stress forced a pump removal -- and repair -- roughly every six months," said Harleyville Maintenance Superintendent Tommy Weeks. "Pump maintenance for this station alone was running nearly $4,000 a year."
