The Bethel Park Municipal Authority is undertaking a phased program to upgrade its 4.92-MGD Piney Fork Wastewater Treatment Plant in South Park, PA, to address operational and process inefficiencies and replace equipment with updated technology. As Engineer of Record for the Authority since 2008, Wade Trim has provided planning, design, construction management and operations assistance for the program as well as on-call engineering services.

The first phase, completed in 2012, focused on secondary digester cover and mixing improvements, new primary clarifier mechanisms, and flow distribution improvements. The second phase, currently in construction, includes replacing the existing rectangular secondary clarifiers with two new 100-foot-diameter circular final clarifiers, piping and building improvements, and adding an ultraviolet (UV) light disinfection system and provisions for future nutrient removal. The UV system and appurtenances will enable full disinfection of the effluent without the need for dechlorination, resulting in zero chlorine residual.

The primary digester is also being upgraded with a new cover and mixing system, similar to improvements completed on the secondary digester. With only one digester in service at a time over the past 3 years, operational practices for sludge processing and solids handling have required significant modifications to maintain plant operations.

Scheduled to be complete in fall 2017, the upgrade program will increase the operational capacity of the digestion system as well as the final clarifiers that were undersized for peak flow conditions, providing adequate treatment for future plant flows. In addition, design is underway to convert an unused building into a new laboratory/office facility for staff.