The Gettysburg Municipal Authority sewer system extends beyond the Borough’s boundaries to provide public sewer service to neighboring municipalities including Straban and Cumberland Townships. Projected development growth, mainly in Straban Township, necessitated expansion of the facilities from 2.45 to 3.0 MGD.
The design solutions converted 25-year-old oxidation ditches into new BNR processes and changed four large equalization tanks into sequencing batch reactors, aerobic digesters and post equalization tanks. A new headworks building with improved screening and grit removal machinery protects the plant from harmful materials while a new 1,000 kilowatt generator supports ongoing operations in case of a power supply outage.
A new computerized SCADA/Process Control System (PCS) was added to provide monitoring and automatic control of all new and existing treatment processes and equipment as well as provide new data collection and reporting capabilities. Prior to the installation of the new PCS, the WWTP had no previous automated control of equipment. A combination of strategically placed plant PLCs, vendor equipment control systems, local HIM screens, operator interface workstations with graphic control screens, and a data historian server were provided.
During the construction phase, BH’s Construction Services Division provided full-time project representation and construction management. Duties included technical support, problem resolution, submittal review and approval, contractor schedule review, job conferences, budget monitoring, photo documentation, quality assurance, change order negotiation and processing, application for payment review, client liaison, substantial and final completion inspection, start-up assistance, and warranty period support and close-out.
Increased plant capacity supports reasonable growth in the areas around Gettysburg. The project was completed on schedule without interruption to ongoing treatment. The design solutions increased average plant capacity by 20% while delivering substantial saving to the Municipal Authority by reusing existing oxidation ditches and equalization tanks and utilizing the existing ultraviolet disinfection system.