LOCATION: Nashua, New Hampshire

DESIGN START: November 2017


IN-SERVICE: August 2020

SIZE & TECHNOLOGY: 2 x 225 kW Engine Anaerobic Digester Gas/Natural Gas Blend

FIRM ROLE: Engineer, Permitting Support, Commissioning

Waldron performed a detailed evaluation of the existing cogeneration building at the Nashua Wastewater Treatment Facility (NWTF). The evaluation included the existing piping, renewable gas production, the two boilers, heat exchangers, gas cleaning room, the exhaust gas flare, and gas hold tank feed system. Waldron provided a preliminary design report on findings and recommended solutions. The renewable gas firing option allowed considerable financial and environmental benefits.

Waldron was the Engineer of Record, environmental and electricity utility permitting agent for the project. The project included the replacement of an existing 300 kW engine generator and associated auxiliary equipment with two 225 kW engine generators, gas blending system for easy startup and to maintain consistent fuel gas quality at the engines, associated heat exchangers, new control system, and new electrical switchgear which enables net metering at the facility. The new design benefited the wastewater facility with significant energy savings and increased the overall operating efficiency, flexibility, and redundancy.