Gresham Smith to Design Upgrades for the City of Lebanon’s Wastewater Treatment Plant
Gresham Smith is pleased to announce a recent contract for wastewater treatment system improvements at the City of Lebanon’s 3-MGD Wastewater Treatment Plant. The firm is providing design, bid- and construction-phase services for the project, which will upgrade the facility’s dewatering, ultraviolet (UV) disinfection and sludge-pumping systems.
“This project continues our longstanding relationship with the City of Lebanon,” commented Ken Roseman, P.E., a senior water resources engineer at Gresham Smith. “We were selected by the client because of our depth of experience in wastewater treatment systems and processes, and we are proud to lend our extensive wastewater management expertise to the project.”
Gresham Smith’s work with these facilities began with an extensive evaluation of the plant’s biosolids equipment, originally installed more than two decades ago, to determine required improvements/upgrades. The analysis was followed by a best-available technology study that evaluated current technology alternatives for the plant’s biosolids dewatering, UV disinfection, and sludge-pumping systems, and made recommendations for “best-fit” upgrades for each system.
The project will replace the plant’s open belt-filter press system with a closed volute dewatering press system. The innovative sludge-dewatering technology offers lower energy consumption and reduces odor migration while producing high-quality dewatered solids. The relatively small size of the volute press allows two volute presses to be installed within the dewatering building’s existing footprint thus providing redundancy (full plant capacity with one unit out of service). This option provides the most cost effective solution for the City. Another alternative considered was the installation of two new belt-filter presses in the existing building. Although potentially achievable, operation and maintenance of two belt presses in the existing building footprint would pose potential safety concerns due to space constraints. Implementation of the belt press option would likely require the added expense of a new building.
The project also includes the replacement of the plant’s 50-year-old sludge/piston pumps with centrifugal disc pump technology. This “new generation” sludge pump system offers greater efficiency, a more consistent sludge flow (which makes the dewatering system run more efficiently), and easier operations and maintenance. New controls will provide fully integrated operation with the volute dewatering system.
Finally, the project includes the replacement and expansion of the facility’s existing UV disinfection system. The new system will incorporate the same disinfection technology but with greatly enhanced components. High-efficiency and long-life amalgam lamps equipped with an automatic chemical/mechanical quartz-sleeve cleaning system will be used. The new UV system will increase disinfection capacity, provide system redundancy/reliability, reduce energy consumption and lower operation costs. Peracetic acid (PAA) will likely be used as an effluent disinfectant to facilitate construction of the new UV system and may be incorporated into the final design as a supplemental/backup disinfectant.
Slated for completion in 2021, Gresham Smith’s budget-conscious upgrades not only provide the City of Lebanon with an enhanced working environment for its employees, but also the system redundancy it has long been seeking.