Coatesville Wastewater Treatment Plant Upgrade and Expansion, Pennsylvania American Water, Lancaster County, PA

Owned and operated by the Pennsylvania American Water Company, the Coatesville Wastewater Treatment Plant serves 6,500 customers in 16 municipalities. Originally constructed in 1931, the plant was upgraded three times by the 1990s, but was unable to handle growth in the Coatesville area and was edging closer to organic loading limits under high flow conditions. Upgrades were required to resolve environmental issues the PADEP had identified in a Consent Order pertaining to sewer capacity overloads at the aging plant.

BH designed the upgrade and expansion of the facility’s systems and processes to increase capacity to 7 MGD. The project was completed on schedule despite the challenges of construction in the midst of an active steel mill and a very tight site and schedule. The finished product also sets the stage to cost effectively increase capacity by another 5 MGD in 10 years.

BH provided professional design, permit, bidding, and construction phase services to expand and upgrade the existing Coatesville Wastewater Treatment Plant (WWTP) to accommodate the regional growth and more stringent discharge criteria. The existing facility was a trickling filter plant with discharge criteria based on a flow rate of 3.85 MGD. The new facility uses oxidation ditches to meet new discharge criteria at an increased flow of 7 MGD.

The majority of the existing WWTP was demolished, including the trickling filters, primary and secondary clarifiers, headworks, and equalization lagoon. The demolition involved draining and cleaning tanks, removing tank equipment and structural walls, and providing the proper backfill to allow new and future structures to be constructed. The expansion required the acquisition of land on the north and south sides of the existing WWTP. The facilities included influent screw pumps, screening and grit removal equipment, two parallel oxidation ditches, three final clarifiers, tertiary filters, and UV disinfection. Sludge is thickened by gravity belt thickeners and discharged to the existing aeration tanks, which were retrofitted to serve as aerobic digesters. Centrifuges were installed in the existing digester building for sludge dewatering, and discharges processed sludge to dumpsters or a covered sludge storage pad.

The old WWTP was situated within an active steel mill owned by Mittal USA. The area is heavily industrialized, so PHMC and PNDI clearances were obtained as part of the Sewage Facilities Plan.