Sewage collection and treatment authorities across the nation are concerned with maintaining lift station pumping capacities during system failures. Traditional design has incorporated a diesel-powered generator to provide backup electricity in the event of a power failure at the station.
Now, tradition is being broken as sewage authorities discover the benefits of backup pumping capacity instead of backup electrical capacity.
Backup pumping capacity supplied by the Godwin Dri-Prime automatic self-priming diesel powered pumpset provides lift stations with 100% pumping redundancy for emergencies, power outages and scheduled preventive maintenance. The reliability issues of transfer switches and control panels of traditional lift station designs become a thing of the past. The following two case studies illustrate how backup pumping capacity has improved lift station reliability and flexibility.
Multi-use pumps
The Orange Water & Sewer Authority (OWASA) of Carrboro and Chapel Hill, N.C., initially purchased a Godwin HLM10M Dri-Prime pumpset and trailer for a bypass needed in its wastewater treatment facility during a clear well upgrade.
In addition, OWASA used the pumpset for six weeks to provide supplementary pumping while installing permanent pump upgrades.
“Godwin was responsive and really worked with us to provide quotes, engineering and service—all with very short notice,” said Barbara Oslund, OWASA engineering manager. “These pumps have other uses too,” continued Oslund. “We’ve put the trailer and original pipe configuration into storage and are now using the pumpset at our raw water pumping facility as a contingency during power outages.”
In a separate application, OWASA used two of the company’s 12-in DPC300 Dri-Prime pumpsets at its wastewater treatment facility. The pumps, designed as critically silenced units, solved the challenge of providing enough capacity to meet peak demands until a major system upgrade could be completed. As permanently installed pumps at the station were taken offline and upgraded, the pumpsets provided supplemental capacity during high-flow conditions.
“I was against diesel pumping initially, but I sure see the benefits now,” said Johnny Johnson, OWASA’s maintenance manager. “The solutions have really helped us during our system upgrades.”
Backup reliability
Maryland Environmental Services (MES) operates lift stations for a correctional facility in Jessup, Md. As part of a planned lift station upgrade, MES’s consulting engineer contacted Godwin to provide the backup system design required on the project.
The company designed backup pumping systems at two lift stations. Each pumping system consisted of the company’s 8-in. Critically Silenced Dri-Prime pumpset that was skid-mounted and permanently installed with the capability of pumping up to three mgd.
Correctional facilities operate on an increased maintenance schedule that requires more pump servicing, generator exercising and line clearing than at a typical municipal lift station.
Therefore, MES required double backup systems for the permanently installed electrical submersible pumps at the station. The pumpsets provide the secondary backup in the event of a primary backup system failure. Additional reliability comes in the form of self-priming diesel pumps, which meets MES’s standard for a 100% operational guarantee.
“Those pumps start every time and do the job,” said Harry McNally, maintenance supervisor for MES. “They give me peace of mind knowing those diesels are there to back us up.”
