Wastewater Treatment & Sewer Collection

Concord General Services Wastewater Treatment Division and Highway and Utilities Division provide services for the collection and treatment of wastewater (PDF) for Concord and portions of Bow and Boscawen. The wastewater collection system contains 163 miles of sanitary sewer line and 8 pump stations throughout Concord. Two wastewater treatment facilities treat the City’s wastewater.

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Hall Street Wastewater Treatment Facility

The main wastewater treatment facility is located at 125 Hall Street in Concord. The facility was built in 1979 and provides wastewater treatment for Concord and portions of Bow. The plant was designed for a capacity of 10.1 million gallons per day and a peak flow capacity of 25.0 million gallons. The plant is currently treating an average of 4 million gallons of wastewater per day. The facility also treats various off-site waste streams, including approximately 5 million gallons of landfill leachate per year and 2 million gallons of domestic septage from local communities. The plant process generates approximately 7,500 wet tons of biosolids annually that are transported off-site to be used as fertilizer or as a component of manufactured topsoil. The facility occupies approximately 28 acres of land, although the City of Concord owns an additional 75 acres around the plant that consists of wooded areas and farm land. Read our feature in the Summer 2017 issue of the NEWEA Journal to see the future options of biosolid stabilization in Concord.

Penacook Wastewater Treatment Facility

The Penacook Wastewater Treatment Plant is located at 7 Penacook Street in Penacook. The plant was originally built in 1973 to treat a significant industrial discharge from the former Allied Leather Tannery. After the tannery closed in 1987, the flow reduced. The plant was converted from a conventional activated sludge plant to a sequencing batch reactor (SBR) process in 2005 after flow conditions were below the capacity. This facility treats an average of 300,000 gallons of wastewater per day and has a treatment capacity of 1.2 million gallons. The former primary clarifier and aeration tank is utilized for wastewater storage during periods of high flow, which occur primarily during the early spring of each year. This facility services the Penacook area of Concord and a portion of Boscawen. Concord is one of two communities (the other being Portsmouth) in New Hampshire that operate two wastewater treatment facilities. Read our feature in the September 2016 issue of TPO Magazine (PDF) for more information about our Penacook Wastewater Treatment Facility.