The Allegheny Valley Joint Sewage Authority (AVJSA) owns and operates a conventional activated sludge wastewater treatment plant (WWTP) rated for an average day flow of 5.5 MGD along with five (5) pump stations. The Authority’s service area is located in the northeast portion of Allegheny County, serving eight communities with a total population of approximately 36,000. The original facilities were constructed in 1962 to service Springdale Township, Springdale Borough, Harmar Township, and Cheswick Borough. In 1980, the facility was upgraded to treat flow from Richland Township, a portion of Fox Chapel, and the Deer Creek Drainage Basin Authority (DCDBA). The DCDBA serves West Deer and Indiana Townships.
In July 2014, the AVJSA entered into a Consent Order and Agreement (CO&A) with the Pennsylvania Department of Environmental Protection (DEP) to eliminate sanitary sewer overflows at each of their five (5) pump stations. The CO&A required extensive flow monitoring, hydraulic modeling, system mapping, and the completion of a regional Act 537 Plan with recommended improvements. The Act 537 Plan required adoption by all eight (8) communities. All work was completed by KLH as required by the CO&A timeline.
The conclusion of the planning process recommended the WWTP be expanded to an average day flow of 8 MGD with a peak flow capacity of 42 MGD. Four (4) of the pump stations would be eliminated and one large pumping facility would be constructed. A new gravity interceptor and wet weather forcemain were also proposed.
KLH began design in April of 2018. Monthly progress meetings were held with KLH staff and the AVJSA Management to review detailed aspects of the design. The treatment plant site posed many design challenges. The site is very constrained and is bound by the Allegheny River to the east and active Norfolk Southern Railway to the west.
It was determined by KLH that the most cost effective solution would be a split train treatment system. The original communities of Springdale Borough, Springdale Township, Harmar Township, and Cheswick Borough would pump to the existing activated sludge WWTP. A new pump station was designed to convey the flow directly to the WWTP via a new wet weather forcemain. The Authority’s existing Tawney Run Interceptor was also upgraded to convey flow to the new pump station. The flow from DCDBA would be pumped through a new separate headworks and new sequential batch reactor (SBR) process.
All flow would be combined and be disinfected by a new ultraviolet (UV) system. The project also includes new digesters along with a multitude of equipment upgrades.
The design has been completed and a Part II Construction Permit was received in March of 2020. AVJSA broke ground on construction in 2022.