Wastewater Treatment Facility Upgrade
Weston & Sampson designed the upgrade to the City of Newburyport’s 3.40-million gallons per day (MGD) Wastewater Treatment Facility (WWTF). The upgrades were recommended by Weston & Sampson as part of the facilities planning effort.
The Newburyport WWTF, reconstructed in 1984, is a secondary activated sludge treatment facility, which provides biological treatment of wastewater prior to discharge of effluent into the Merrimack River (per NPDES Permit No. MA0101427). The objective of the WWTF Improvements Project was to modernize and improve the unit processes to treat the current and future flows and loads to the WWTF and minimize the potential for future NPDES permit exceedances to the Merrimack River. To accomplish this goal, improvements to support facilities (buildings, electrical, instrumentation & control systems, etc.) were necessary.
The main components of the proposed project include improvement/upgrade of the existing treatment processes and equipment, reconstruction of the existing process building, and upgrade of the current aeration system from mechanical surface aeration to fine bubble diffused aeration (which required the construction of a new building/enclosure to house the aeration blower equipment).
The project also included construction of a new Operations, Control and Laboratory (OCL) building on a lot adjacent to the existing facility on Water Street, which was historically used for boat sales/storage. The site was known to contain petroleum-contaminated soils within a portion of the building area. Since this property was a Massachusetts 21E site, extensive remediation measures for this contamination were undertaken, including soil excavation/recycling, free-phase petroleum extraction, and construction of a sub-slab depressurization system for the new OCL building.
Weston & Sampson conducted a full geotechnical and environmental soil boring exploration program and designed the foundation for the building. Field/laboratory tests were conducted to determine physical and engineering properties. Stormwater and site civil utilities/features were also designed. Weston & Sampson developed a full cost estimate for the project and provided bidding assistance to the city. A full construction project schedule was also developed and included monitoring by a full-time Weston & Sampson resident engineer.
Officially certified as LEED Gold under the Leadership in Energy and Environmental Design (LEED) program administered by the US Green Building Council, the new OCL building was designed to fit architecturally into the surrounding neighborhood and incorporate LEED principles.
The WWTF Improvements Project design was completed under a fast-track schedule to take advantage of construction phase state/federal funding sources, including the Massachusetts State Revolving Fund (SRF) loan program, the American Recovery and Reinvestment Act (ARRA) funding program, and the Green Infrastructure Reserve fund.
The second contract associated with this project included reconstruction of the existing Operations Building (including the solids dewatering facilities), headworks improvements, influent pumping improvements, chemical feed improvements, and odor control improvements.
The project includes complex construction sequencing requirements and provisions for maintaining continuous efficient operation of the WWTF during construction. These operations and sequencing controls are further complicated by the small site and proximity to neighbors.