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Case Study grinder pumps that are less effective in dealing with hard or stringy foreign materials, the N-pump maintains con- tinuous flow by the leading edge of the rotating impeller passing across a stationary relief groove at the suction port of the pump. The dynamic action cleans and passes any rags, stringy materials, and many solids without com- promising hydraulic efficiency. The elimination of drag imposed by such buildups inherently reduces the N-pump energy requirement. The savings for Jackson Energy should potentially accrue into tens of thousands of dollars over the expected service life of the replacement pumps. "The electrical cost reductions were immediate," Myracle noted. "Our monthly cost dropped from $78 per month to $39.95, and we've experienced a virtual elimination of high-level alarms that required emer- gency dispatches and extra man-hour expense or the need to defer work elsewhere on the system. Management could clearly see the savings in actual electric utility costs." "Our total annual reduction in oper- ating costs following the upgrade ran $5,737.92," he said. "At that rate, the total costs to replace the two pumps could be recovered in just 1.19 years!" With the new Flygt pumps in place, the Rolling Acres Lift Station now requires only a routine inspection once a month by one field technician. The station is monitored 24/7 on the util- ity's SCADA at a central dispatch center whose record of significantly reduced alarms further supports the promised reliability of the new pumps. He went on to note that Jackson Energy recently annexed a large area in the northeast part of the county that will receive a broader scope of improved services. The annexation and merger of sewer services will require removal of some stations in favor of building a consolidated 600-gpm station. The new Ashport Road Lift Station is engineered beyond the initial rating for expansion up to 1000 gpm. Based on Myracle's firsthand experience at the Rolling Acres Lift Station, the N-pumps became the preferred specification for the new sta- tion serving the annexed service area. "Rolling Acres proved on a small scale the benefits of the N-type impeller," he said. "When planning the new station we could clearly see on paper that cost comparisons on a larger scale also favored Flygt N-Pumps." Steve London is president of Steven London Associates. London has an extensive background as a writer and editor. For the past 17 years the company has been involved in the development of application stories that highlight various solutions for water management professionals. London can be contacted at slondon@comcast.net. 36 Water Online The Magazine, Wastewater Edition ■ wateronline.com