Utilizing Existing Resources: Rehabilitation of 72″ Steel Lock-Bar Pipe

The Western Bays of Long Island New York were once a productive fishing area. Much of the excess nitrogen in the Bay is attributed to wastewater treatment facilities that discharge directly into the Bays. In an effort to improve the marsh’s ecosystem, the New York State Department of Environmental Conservation (NYSDEC) and Nassau County Department of Public Works entered into a unique partnership to implement a Design–Build project that would remove up to 90% of the nitrogen loading in an already compromised area. Up to 75 million gallons per day (MGD) of wet and dry weather flow needed to be diverted from the Bay Park Sewage Treatment Plant (BPSTP) to the Cedar Creek Water Pollution Control Plant (CCWPCP) to be discharged via the existing ocean outfall at that site. This Bay Park Conveyance Project would require the construction of a 12.4-mi long force main from the South Shore Water Reclamation Facility to the existing Cedar Creek Water Pollution Control Plant (WPCP) outfall. The plan was to utilize 7.3 mi of an existing abandoned 72″ steel lock-bar pipe. This aqueduct would require full rehabilitation of the existing pipeline. The preliminary design for the 72″ pipeline was to rehabilitate the pipe by sliplining with Fiberglass Reinforced Polymer Mortar (FRPM) pipe or Steel pipe. Carbon Fiber Reinforced Polymer (CFRP) lining would be considered, but on very limited sections of pipeline due to installation cost and efficiency. The design criteria developed provided the basis for the system design, including appropriate standards, Mandatory Requirement for performance and/or materials, and product specifications. This paper will review this project in detail from cradle to grave covering aspects from the background with initial design parameters and to the process of final design and construction completion. Included in this presentation will also be lessons learned throughout the design and construction process.