The Town of Riverhead formed the Calverton Sewer District in 1999 after taking over the formal Naval Weapons Industrial Reserve Plant from the US Navy to create the Enterprise Park at Calverton (EPCAL). The existing sewage treatment plant was originally built in the late 1960’s and the sanitary infrastructure improvements necessary to support future development of the EPCAL site include upgrading the existing sewage treatment plant. The project also proposed to relocate the existing surface water outfall to a groundwater recharge site located outside the nationally recognized Peconic Estuary watershed.
To achieve the goal of the upgrade, H2M architects + engineers designed the new process to start with a new below grade concrete screening channel with fine screens with integral screenings washing/compacting zones. Screened influent then discharges into an upgraded influent pump station where dry pit pumps were replaced with new submersible pumps. Following the pre-treatment systems, the existing final settling tanks were converted to new pre-equalization holding tanks including a new pre-equalization submersible pump station which conveys influent to the new Membrane Bioreactor (MBR) process. An existing aeration basin was converted with new concrete divider walls into a dual train MBR process, each train including an anoxic basin and aeration/MBR basin for biological nutrient removal. Treated and clarified water, or permeate, is drawn from the ultrafiltration membrane filters and transferred to the new effluent pump station before travelling through a new 2-mile force main to the final recharge basins. Waste sludge from the MBR process is pumped and to and held within new sludge holding tanks, located in the remaining existing aeration basin.
To support the new facility, new electrical distribution gear and a natural gas emergency generator were provided. The existing control building has been repurposed with the new permeate pumps, aeration blowers and motor control centers including variable frequency drives, motor starters and low voltage transformer. To provide the operations team with the tools necessary to monitor and control the MBR process, new lab casework and testing equipment were purchased. Finally, new control panels were provided for each process including custom Programmable Logic Controllers (PLC) for the needs of this facility. An ethernet network is part of the design such that the various portions of the process can communicate with each other, and ultimately a Supervisorial Control and Data Acquisition (SCADA) computer receives all the data of the facility to provide remote connectivity to the support teams ranging from the programmer that supplied the control panel to the engineers for providing assistance.
With the completion of this upgrade, the facility has been upgraded to a 100,000 gallon per day treatment plant. The future planning and development will dictate the ultimate capacity of the collection system; however this facility now has the ability to be upgraded in modules to meet the future needs of the Calverton Sewer District. H2M is proud to have worked with the Town as part of the planning, design and construction of this first phase and will continue to work the with Town to provide operations support and engineering assistance as the facility moves into the future