The expansion and upgrade of the Peirce Island wastewater treatment plant in Portsmouth, NH was completed by the end of August 2020. Penetron crystalline products were specified as a waterproofing solution for the massive concrete structures.
The $70-million upgrade project was the largest single construction project ever undertaken by the City of Portsmouth, New Hampshire. Designed by AECOM, an engineering consultancy, the upgraded Peirce Island facility now provides secondary treatment and nitrogen removal that meets strict federal environmental standards. The upgrades added to the 50-year-old plant by Methuen Construction, the project contractor, include a new filter building with a biologically aerated/anoxic (BAF) filter (using the Kruger BioSTYR™ technology), a new headworks building with a garage, electrical room, IT room, and control room, and a new solids building with the existing solids building re-purposed as an operations/lab building.
Originally constructed in 1965 to treat an average daily flow of 1.5 million gallons of wastewater per day (later expanded to 4.8 million gallons of wastewater), the upgraded Peirce Island WWTP now handles a daily flow of up to 6.1 million gallons of wastewater. The treated wastewater effluent is discharged to the Piscataqua River through a 24 inch diameter single port outfall.
Better Protection for Local Water Quality
“Some components from the previous plant remain in the new layout but the upgrade work was significant,” adds Christopher Chen, Director of The Penetron Group. “The improved capabilities of the new plant to remove nitrogen from wastewater and treat previously untreated stormwater run-off is essential for protecting the quality of the Piscataqua River, which receives the treated effluent from the plant.”
AECOM specified PENETRON ADMIX SB for the new concrete structures, primarily the new BAF building, which is approximately 25 feet above the existing grade and with another 15 feet of the structure below grade. The walls of the building are massive 2-foot-thick concrete structures measuring about 40 feet tall, with the longest wall over 200 feet in length. J.G. MacLellan Concrete Co., the ready-mix supplier, added PENETRON ADMIX SB to about 17,000 yds3 of concrete mix, which was mostly used for the BAF building’s key structural elements.
Keeping Water and Chemicals Out of Concrete
When added to the concrete mix during batching, the active ingredients in PENETRON ADMIX SB react in a catalytic reaction with moisture in fresh concrete and by-products of cement hydration. This chemical reaction generates a non-soluble crystalline formation throughout the pores and capillary tracts of the concrete. This prevents water and water-borne chemicals from entering the concrete structures, even under high hydrostatic pressure. In addition, any cracks that may develop during the lifetime of the concrete automatically self-heal, resulting in waterproof and durable concrete for the lifespan of the structure.
“The new Peirce Island facility offers increased treatment capacity, cleaner effluent and – thanks to Penetron crystalline technology – a markedly more durable treatment plant with decreased maintenance requirements,” notes Christopher Chen.
Durable concrete thanks to Penetron: The $70-million Peirce Island wastewater treatment plant upgrade was the largest single construction project ever completed by the City of Portsmouth, NH.
Meets strict EPA standards: This perspective gives an idea of the massive dimensions of one of the Peirce Island treatment tanks that helps treat up to 6.1 million gallons of wastewater daily.
