Lower Meramec Lift Station

Home \| What We Do \| Awards \| Who We Are \| In The News \| Contact Us \| Careers \| Links
	Search:

Lower Meramec Lift Station
St. Louis, Missouri

One of the largest and deepest lift stations in the St. Louis area
Key design considerations were site aesthetics and minimizing any offsite issues that would impact the local community
Separate screen structure provides protection for the pumps from damage that could result from debris traveling down the tunnel
Custom-designed combination bar screen and raking machine removes debris from screen structure and conveys it to ground surface for disposal without requiring frequent, labor-intensive maintenance work

100' diameter main lift station shaft extends 226' below grade

Horner & Shifrin, in conjunction with a carefully-chosen group of architectural, civil, and electrical MBE subconsultants, designed one of the largest and deepest sewage lift stations in the St. Louis area for the Metropolitan St. Louis Sewer District (MSD). This lift station receives flow from a 96-inch diameter deep tunnel system, has a design peak pumping capacity of 140,625 gallons per minute (gpm) or 202.5 million gallons per day (MGD), and conveys that flow into a new wastewater treatment plant.

The lift station is approximately 100 feet in diameter and extends 226 feet below grade. This below-grade concrete shaft contains two levels. The bottom level contains two 64” diameter vertical pipe manifolds and associated valves. A second floor, located approximately 33 feet above, contains pumps and valve hydraulic power packs. On this floor are two 800 horsepower (HP), 15 MGD capacity and three 2,000 HP, 40.5 MGD capacity centrifugal pumps to convey the current peak design flow of 67.5 MGD to the treatment plant. The lift station has been designed for the future installation of one additional 2,000 HP pump, plus the replacement of the two 800 HP pumps with 2,000 HP pumps to bring the lift station capacity to 202.5 MGD.

Lift station building was designed to be aesthetically pleasing

Site aesthetics was a key design consideration as well as minimizing any offsite issues that would impact the local community. A considerable effort was placed on the architectural appearance of the lift station and screen structure buildings. In addition, architectural walls were installed to screen mechanical support equipment that is outdoors to improve the facility's “curb appeal.” The above-grade portion of the lift station consists of a 56-foot-tall, two-story, circular, steel-framed block and brick structure approximately 120 feet in diameter supported on the 100-foot-diameter concrete slurry wall shaft via a cantilevered grade beam. The ground floor is supported by structural framing connected to the interior shaft wall and stair shafts, thereby leaving 60% of the floor area open in the center for return air flow and to allow removal of pumps, valves, and piping for maintenance. The ground floor houses all 4,160/480 volt electrical gear. The 800 HP pumps are controlled by 4,160 volt variable frequency drives (VFDs) and the 2,000 HP pumps are controlled by “dual” VFD units that utilize one VFD and multiple switches to be able to start either of two large pumps in a pair on the VFD or across-the-line in an emergency.

Lift station electrical and control equipment featues
redundant systems for use in an emergency

The mezzanine level houses six air handling units that deliver 160,000 cubic feet per minute (cfm) of air for ventilation. This system doubles as a smoke exhaust system to comply with code requirements. The air handling units are equipped with total heat recovery wheels to scavenge waste heat, gas-fired heating systems, and evaporative coolers for summer protection of sensitive electrical gear.

A separate screen structure, located approximately 100 feet “upstream” of the lift station, provides protection for the pumps from damage that could result from debris traveling down the tunnel. A state-of-the-art inorganic media biofilter was designed to treat air emissions from the screen structure. The screen structure consists of a 31-foot-diameter concrete lined shaft that extends 188 feet below grade. The 96-inch-diameter tunnel pipe discharges into two 6-foot-wide screen channels. The custom-designed combination bar screen and raking machine removes the debris from the screen structure and conveys it to the ground surface for disposal without requiring frequent, labor-intensive maintenance work. This 48-foot by 53-foot block and brick structure was constructed on a grade beam cantilevered off the slurry wall shaft. The building is classified as an explosive environment.

In addition, MSD desired to treat odorous air flows that are conveyed to the screen structure by the tunnel, to prevent offensive odors from emanating to nearby residential areas. The screen shaft ventilation system was equipped with a state-of-the-art biofilter to treat the airflow from this screen structure.

The entire facility was designed to allow for remote operation by MSD staff via a distributed control system.

"2008 Engineering Excellence Grand Conceptor Award"
American Council of Engineering Companies of Missouri (ACEC/MO)

<< Back