To:
From:
Re:
B. Motion:
Attachments:
Discussion:
City of Nashua, Public Works Division
Board of Public Works Meeting Date: May 25, 2022
David L. Boucher, Superintendent
Wastewater Department
Amendment to Dry Well Valve and Pipe Replacement project-Preliminary Design
Phase Services
To approve an amendment to the contract with Wright Pierce for the preliminary
design plans and specifications for the Dry Well Valve and Pipe Replacement
project in an amount not to exceed $78,300. Funding for this contract will be
through Department: 169 Wastewater; Fund: Wastewater Activities: Washpress
Upgrade and Screening Odor Control.
Wright Pierce Scope of Work and Fee Schedule
The Nashua Wastewater Treatment Facility dry well, consisting of four large
capacity pumps, associated valves and piping is in need of upgrades. The design
phase services for this project was awarded to Wright Pierce in January 2022.
Wright Pierce is currently in the early phase of the design.
Since this project started, two other capital project previously approved for
funding, could be combined with this project since all work is in the same general
vicinity of the plant. These two projects are the screening garage odor control unit
and the wash press chute modifications.
An odor control unit is needed for the screenings garage, which is located in the
floor above the dry well valve upgrades. The odor coming from the screenings
garage is the worst in the plant and an odor control unit on the exhaust fan is
needed to control the strong odors from the garage. Modifications to the wash
press is also needed as solid inorganic material in the influent wastewater, such as
asphalt stones from road work, synthetic rags and miscellaneous plastic debris can
clog the screening pipe. This usually happens during a big storm when high
turbulence can push small stone and other debris to the influent headwork screens.
A modification to the wash press chute is needed to minimize the potential for the
chute to become clogged with debris.
Wright Pierce has a working knowledge of what needs to be done for these 2
smaller projects, which will be added to the scope of the construction of the dry
well valve project. By including these project within the bigger dry well valve
upgrades project, the City will achieve economy of scale and better pricing.
Wright Pierce costs for the preliminary design (Phase I) is $105,800. Their costs
for adding these 2 smaller projects is $78,300. The new total costs for the
preliminary design phase comes to $184,100 with these 2 projects added.
