Godwin’s Dri-Prime Backup SystemTM (DBSTM) provides independently powered pumping for emergencies including primary power, switch gear and sewage pump failure or repair; and primary pumping during routine maintenance. These conveniences proved particularly appealing to Saint Mary’s Metropolitan Commission (St. Mary’s Metcom) in St. Mary’s County, MD.
With an influx of new home and community construction, St. Mary’s Metcom needed to install a new pump station equipped with a contingency plan that could accommodate 267 gpm of raw sewage at 55 feet of total dynamic head (TDH). Aware of the potential hazards to the new pump station in this residential area, St. Mary’s wanted to incorporate a backup system that could sustain pumping regardless of heavy rain, routine maintenance or electrical outage.
“One option was to have a generator with all the controls (diesel, propane or natural gas) and the associated separate tank and the wiring,” said Gary Reynolds of St. Mary’s Metcom. “The commonsense solution was to find a unit that does it all.”
The utility selected Godwin’s four-inch by four-inch CD100M DBS automatic priming system powered by a John Deere 3015D diesel engine. This skid mounted unit features a battery charger and block heater and is capable of reaching flows to 750 gpm and TDH to 115 feet through float controls and a programmable control panel that alerts the main control center when the backup system begins pumping. In addition, the DBS is housed in a critically silenced, weather-resistant enclosure that keeps the noise level to 68 dBA or less at a distance of 30 feet, which is important at this residential location.
The emergency backup pumping system and the lift station pump system are separate and not dependent upon each other, so if power outages result in failure at the main lift station, the independently power, self-starting DBS automatically takes over.
“With no transfer switch and much less wiring that can be damaged in an electrical storm, this pump saves worry,” Reynolds said. “It operates only when needed, and is sure to run when it needs to.”
Regardless of the reason, when the sewer level rises, the DBS automatic priming feature removes air from the suction line, creating a vacuum that allows the sewage to rise and the pump to establish prime. The pumpset continues to operate and pump the required flow and shuts off when either the wet well is lowered or the electricity is restored, and the primary system re-takes control.
