Managed and run by the Suffolk County Department of Public Works, the Bergen Point Wastewater Treatment Facility (WWTP) discharges treated effluent into the Atlantic Ocean from an outfall that runs under the Great South Bay and under Jones Beach. It has been decided that the 14,200-foot-long section of the outfall that stretches from the WWTP to Jones Beach Island and passes under Great South Bay is in a failing state and replacement is required.
As part of a joint venture, OHL USA is building a 10-foot diameter tunnel under the Great South Bay via a mixture of soft soil materials. The new 2.6-mile tunnel will fix the existing pipe’s future deterioration issues and will have a longer lifetime. Inside the tube, no carrier pipes will be installed; the lined tunnel itself will act as the replacement outfall.
Using ground freezing methods, the TBM entry and exit shafts are installed and reach to a depth of 80 to 100 feet below ground. Using a slurry TBM, the tunnel is excavated and is simultaneously lined with 48-inch-wide precast concrete section circles. The construction of the shaft is split into major phases of operation, including site planning, launch shaft excavation and installation of the launch shaft.
The scope of work also includes the removal of the pipes and valves at the current Final Effluent Pump Station, the construction of the new piping site, gates, valve chamber, meter chamber, chamber 3B, and the development of staging and mucking areas. Piping operation on the Barrier Island at the current outfall would stretch from the receiving shaft to the new connection.