West Pennsboro Pump Station No. 3

Key Accomplishments

• The packaged wastewater pumping system utilized duplex horizontal self-priming centrifugal pumps designed specifically for raw sanitary sewage service. The specified Gorman-Rupp T4A71S-B pumps incorporated 4-inch suction and discharge connections, 15-horsepower motors, 3-inch solids-passing capability and a minimum 25-foot reprime lift.
• Each pump was designed for approximately 300 gallons per minute at 51 feet of total dynamic head, with the pumping system configured for unattended automatic operation and reliable reprime capability for sanitary-sewage service. The complete packaged system incorporated pumps, motors, valves, piping, controls and related appurtenances as a coordinated, factory-tested pumping assembly.
• The station incorporated an Allen-Bradley CompactLogix 5370 L2 PLC-based control system with digital and analog I/O, EtherNet/IP communications and operator-interface functions. The PLC provided lead/lag pump sequencing, automatic alternation, wet-well-level monitoring, pump start/stop control, alarm functions and automatic control of standby operation.
• Emergency pumping capability was provided through an LPG-fueled, water-cooled standby engine integrated with the pumping system. The engine was designed for automatic operation during utility-power failure as well as scheduled exercise cycles, providing an independent means of operating the pumping equipment during emergency conditions.
• The project included extensive pump-station monitoring and alarm capabilities. High and low wet-well levels, phase failure, high pump temperature, station low temperature, engine failure, DC power failure and other operating conditions were incorporated into the control and alarm system.
• A cellular remote-alarm system provided off-site notification and monitoring of station conditions. The specified OmniSite system could place telephone calls and send pager messages, SMS texts and emails, while secure Internet access allowed operators to view alarm status, alarm history and pump run-time information.
• The station underwent coordinated pre-startup inspection, field startup and performance testing with the equipment manufacturer, Engineer and Owner. Testing included operation under both utility and emergency power, pump cycling through the force main, instrumentation calibration, pump-control verification, liquid-level-control testing and confirmation of alarm operation.
• Johnston Construction Company served as the Civil Subcontractor for the West Pennsboro Pump Station No. 3 project in Cumberland County, Pennsylvania. The project was constructed for the West Pennsboro Township Municipal Authority and designed by Herbert, Rowland & Grubic, Inc., under HRG Project No. 007213.0425.
• JCC’s civil subcontract work supported construction of a modern municipal wastewater pumping facility incorporating a precast reinforced-concrete wet well and an integrated packaged pumping system. The wet well was designed for groundwater and flotation conditions and included watertight precast construction, sealed pipe penetrations, access hatches, exterior protective coating and a dedicated odor-control vent.
• The pumping system was based on horizontal self-priming centrifugal pumps specifically designed for raw, unscreened domestic sanitary sewage. Each specified Gorman-Rupp T4A71S-B pump incorporated a 15-horsepower motor and 3-inch solids-passing capability and was designed to deliver approximately 300 gallons per minute at 51 feet total dynamic head.
• Controls for the new station incorporated an Allen-Bradley CompactLogix 5370 L2 programmable logic controller. The PLC continuously monitored wet-well conditions and controlled lead and lag pump operation, automatic pump alternation, start and stop levels, alarms and emergency operating sequences. An air-bubbler level-control system and independent alarm functions provided additional monitoring of pump-station operation.
• The facility also incorporated an LPG-fueled water-cooled standby engine to provide pumping capability during loss of utility power. The controls were designed to automatically transition to emergency operation based on wet-well conditions and to exercise the standby system on a programmed schedule.