Wastewater > Project Case Study

Wastewater Facilities Planning and Upgrade

Soon after constructing an aerated lagoon treatment facility in the 1990’s, the Town of Jaffrey received stringent, new, unachievable discharge limits for ammonia, copper and BOD due to limited dilution in the Contoocook River. The Town and its previous engineering consultants worked with NHDES and USEPA without success throughout the 1990’s in trying to develop a wastewater management plan that would assure compliance with the state and federal water quality regulations, and be affordable for the Town’s sewer users. In late 2000, the Town selected Wright-Pierce to perform a comprehensive evaluation of wastewater treatment and discharge options, including land disposal of effluent, and to assist in obtaining federal and state funding to help pay for the recommended wastewater management plan.

Wright-Pierce coordinated with the Town to conduct a multiple approach strategy to achieve both regulatory compliance and the schedule requirements of Administrative Orders issued by NHDES and USEPA. Wright-Pierce performed river modeling to challenge the proposed nutrient criteria and a hydrogeologic investigation of multiple potential discharge sites while negotiating innovative NPDES discharge permit conditions. Alternatives for potential discharge alternatives were also evaluated. This phase required coordination with NHDES on a total maximum daily load (TMDL) study of the Contoocook River and the State’s first attempt at nutrient modeling in a river.

The recommended plan included a 1.25 MGD enhanced biological nutrient removal oxidation ditch treatment facility with centrifuge sludge dewatering and UV disinfection. The state-of-the-art treatment facility will allow compliance with stringent nitrogen and phosphorus discharge limits at significantly lower power and O&M costs than other available treatment technologies. A $2M effluent filtration system, which was initially required by EPA, was removed from the project based on the affordability analysis and on quality monitoring performed by Wright-Pierce which demonstrated that more stringent phosphorus standards would produce no meaningful water quality benefit.

With Wright-Pierce assistance, the Town obtained $11.7 million in state and federal funding for the $18 million project. Grants were obtained from NHDES, USDA Rural Development, US Economic Development Authority (EDA), and EPA STAG. The remainder of the project costs are funded with low interest SRF loans.

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