When the West Side sewage pump station in Onondaga County, New York, prepared to undergo its first major expansion and upgrade in over 30 years, the project required a bypass system to move a peak flow of 30 million gpd.

The West Side pump station is the second largest pump station in Onondaga County, taking in about 8 million gpd of sewage from communities in the western suburbs, then pumping it to a nearby wastewater treatment plant. The expansion and upgrades to the station were designed to add more sewer capacity to help reduce overflows into Onondaga Lake during heavy rains. The project would also expand the pump station’s capacity and increase its efficiency.

The county’s Department of Water Environment Protection hired local contractor C.O. Falter Construction to oversee the bypass project. The initial design called for using the station’s existing pumps during the expansion and upgrades. But it was later determined those pumps could only handle 19 mgd.

Accurate flow data and flow documentation is critical to properly size the bypass pumping system. If the anticipated peak flow isn’t determined correctly, then the temporary bypass will not be able to sustain the sewer system during rehabilitation and risks of contamination to the surrounding environment increase considerably as the possibility of a sewage spill becomes more likely.

After determining the initial design missed the target by 25%, it became apparent the job would require a temporary bypass system to meet the maximum flow capacity.

Tight footprint

C.O. Falter Construction engaged Xylem to design and install a temporary system to convey the full amount of flow within the same footprint as the original pumps. This helped the project avoid road closures and traffic delays.

To stay within the compact station area, Xylem recommended two Flygt N 3312 pumps that could plumb into the existing piping system, resulting in material costs savings.

In addition to the two Flygt N 3312 pumps, the bypass system at the West Side pump station also included three Godwin Dri-Prime CD300M pumps. Housed in a specially designed, acoustically silenced enclosure to minimize noise pollution, the attenuated units reduced pump noise levels to 69 dBs at 30 feet, meeting OSHA noise exposure standards.

With the pump station located in a high-visibility area between Interstate 690 and Onondaga Lake and overlooking the New York State Fairgrounds, the pump equipment representative explains that loud diesel equipment would not have been appreciated.

One Godwin CD300M pump was set up on grade and away from the construction area, with the other two diesel-driven pumps serving as backups. Backup systems are essential in any bypass operation, as they protect against instances of unexpected high flows or primary system failure during pipe rehabilitation. The combination of reliable primary pumps supported by a robust backup system offers peace of mind, as service is guaranteed to be maintained during loss of power — whether from a scheduled outage or a natural disaster.

The combination of diesel pumps and electric submersible pumps allowed the temporary bypass to operate at maximum efficiency, offering a flexible solution for fluctuating wastewater flow levels.

The diesel pump model used for this project also has the capacity to handle solids up to 3.7 inches in diameter, allowing a wide range of slurries and fibrous materials to easily pass through the pump’s impeller and resist clogging. This, along with the portability of the pump, makes it an excellent choice in challenging dewatering applications where sewage, sludge or a large volume of water needs to be removed or redirected.

The Godwin pumps were fitted with variable- frequency drives, enabling operators to control the motor speed and reach the required duty point, ensuring optimum operating efficiency throughout the project. To save energy and diesel fuel costs, each pump activated only when increased flows called for additional pump activity.

Cost savings

Renting the equipment versus the capital expenditure of purchasing it outright also provided a significant cost savings for Onondaga County. Pump rental solutions offer the flexibility to handle complex and evolving applications without having to invest in expensive pumping equipment that isn’t required on an ongoing basis.

“A bypass of this size isn’t something you do every day,” says the pump supplier representative. “For larger projects, end users don’t have justification for the cost of the pumps.”

Along with providing pumping equipment without capital expenditure, the Department of Water Environment Protection had access to engineers, product experts and service technicians to ensure operations continued uninterrupted.

Remote monitoring

The Department of Water Environment Protection and its contractor also needed access to system operations when staff was not on site. To ensure the bypass ran smoothly for the duration of the project, a Godwin advanced remote monitoring and control panel was installed to continuously collect data from the VFD and transducer.

The bypass system went online in March 2018 and ran 24/7 through September 2018. It was set up to emulate the response and flows of the plant’s permanent equipment, and remote connectivity enabled the various parties involved in the project to continually monitor the pumps from any location via any smart device.

The remote monitoring capability was especially helpful when the project first got up and running, and fluctuations in the water flow varied widely due to the shifting student population at nearby Syracuse University.

“Syracuse is a huge college town, so there were higher flows when school was in session and then capacity dropped in the summer,” says the pump supplier representative. “That’s the beauty of remote monitoring. We can watch the equipment and do troubleshooting as needed without having to be on site.”

With the ability to set parameters and alarms for minor issues, C.O. Falter Construction could address potential problems before they caused a major shutdown, optimizing manpower throughout the project.

Dan Falter, project manager for C.O. Falter Construction, notes the ease with which anyone involved in the expansion and upgrade project could monitor the system in real time from remote locations.

“It’s pretty slick,” Falter says. “If a pump goes down, we’re alerted even if we’re not on site. The remote monitoring capability provides peace of mind, which is everything.”

Along with flexibility and convenience, the remote monitoring and controls capabilities also proved more economical than traditional manned pump watch, representing a substantial costs savings of nearly $57,000. 

About the Author

Darrin Ruiz is the Northeast regional applications engineer for Xylem and its Godwin and Flygt brand pumps, serving the municipal, construction and industrial markets.