As part of a Consent Order and Agreement (COA), the Western Westmoreland Municipal Authority (WWMA) in North Huntingdon, PA, has reached the second phase of a 3-phase sewer system improvements project designed to eliminate sanitary sewer overflows into Brush Creek during wet weather events. The first phase featured a new 45-MGD influent pump station at the Brush Creek Wastewater Treatment Plant (WWTP) and a new 7-MG equalization basin near the WWTP. The remaining phases focus on replacement of 7 miles of interceptor along Brush Creek, Bushy Run, and Coal Tar Run, which include state road, rail and bridge crossings. The entire 6-year WWMA COA improvements project is required to be complete by May 2020.

The pump station is a multi-purpose facility with the capacity to pump 15 MGD to the WWTP and 30 MGD to the equalization basin after WWTP capacity has been maximized. The pump station consists of 2 mechanical bar screens, 3 raw sewage pumps and 4 wet weather pumps. All pumps share a common discharge pipe that allows flow to be pumped to the equalization basin for storage and drained back by gravity through the same pipe to the WWTP for treatment when capacity is available. In addition, WWTP upgrades are underway to improve hydraulic performance and operations.

The equalization basin is an above-ground, wire- and strand-wound, circular, prestressed concrete tank sited on a hill near the WWTP. Operations and maintenance access is provided via a newly constructed road. A utility tunnel installed below an active state road connects the WWTP to the pump station to convey process piping and provides a safe means for WWMA personnel to cross between the two facilities.

For Phases 2 and 3, the interceptor was upsized from 8- to 33-inch-diameter to 12- to 48-inch-diameter pipe to increase capacity. The existing interceptor has major sections either in the toe of the stream bank or in the stream itself. While the interceptor improvements were moved out of the stream where possible, large portions of the interceptor upgrades are within the limits of the stream that required significant regulatory permitting for bypassing creek flows while upgrading an active sewer system. In addition, the interceptor design accommodates 3 miles of asbestos cement pipe (ACP) using a parallel system that allows the existing ACP interceptor to be removed from service and left in place. Phase 3 interceptor work is anticipated to be bid in the spring/early summer of 2019. All three phases were funded by over $40 million in PENNVEST loans available through the Pennsylvania Infrastructure Investment Authority, with the third phase receiving $3.5 million in partial grant subsidy.