Wastewater Pump Station on Governors Island

New York, NY

H2M was selected to investigate and provide design services for improvements to the wastewater pump station on Governors Island in New York City.

The almost 50-year-old pump station conveys all wastewater on the 172-acre Governors Island through a force main under Buttermilk Channel to Brooklyn. The pump station is a single-story 30-foot by 25-foot masonry building above grade with two basement levels. The pump station was flooded during Hurricane Sandy.

The design for station improvements included replacement of shaft driven pumps with submersible wastewater pumps; replacement of comminutor; lightning protection on building; replacement of doors with flood doors; replacement of windows with higher sills; asbestos abatement of roofing materials; replacement of roof; replacement of pump controls; elevation of electrical equipment within building; new ventilation system for wet well and dry well; painting of interior and exterior; removal and disposal of unused fuel tank; addition of wastewater flow meter; new LED lighting; a backflow preventer on water service; replacement of valves; modification of force main piping to allow connection of portable pumps; addition of a handwash sink; replacement of sump pump; and addition of an alarm system.

An approximately 2,200-foot-long, 14-inch diameter ductile iron force main conveys wastewater from the pump station under Buttermilk Channel to Brooklyn. The deepest part of the pipe is at elevation -51. Prior to design and to determine adequacy for higher flows from future development, a television inspection was conducted of 450 feet of 24-inch gravity sewer downstream of the force main discharge and 87-feet of the downstream end of the force main pipe. An internal tethered acoustic survey was conducted to identify and locate leaks and gas pockets along 1,796 feet of the upstream end of the force main while it remained in service. The device was inserted in an existing 2-inch tap on a wye in the drywell.

During the design phase, H2M evaluated the wastewater pump capacity to convey flow from potential development over a 20-year period as envisioned by The Trust for Governors Island and provided a footprint for potential future expansion of the pump station wet well. The pump station was evaluated to identify necessary repairs and improvements to bring the station into a state of good repair and into compliance with applicable codes and standards. Following construction, the pump station will provide reliable operation, have a rehabilitated building envelope, and be more resilient to potential flooding.