Peirce Island Wastewater Facility Upgrade Project

This project is the largest that the City has undertaken. The Peirce Island Wastewater Treatment Facility (WWTF) upgrade expands treatment at the plant to an advanced secondary process which removes organics and nitrogen. Progress videos are available on our YouTube page, shown below.

Project Contact

Public Meetings


Monthly public meetings with City staff, the Contractor and other officials involved in the project are typically held every third Wednesday each month at 11 a.m. in City Hall's Conference Room A to ensure that citizens are informed; these meetings are broadcasted and available on the City’s YouTube channel, with presentations and notes available at Wastewater Public Meetings


Anticipated Construction Traffic Volume: High

This work this week will include, but not be limited to:

*10/1/18 – 12/16/18: First shift work beginning at 6 a.m. to complete carpentry work; no over length trucks will be picked up by police detail prior to 6:30 a.m. to be brought to the site for unloading at 7 a.m. Second shift (2:30 p.m. – 11 p.m.) work to occur to install pipe and fittings in the BAF Building pipe gallery.


  • Install mechanical process piping and equipment in the Solids Building
  • Continue construction of masonry in the Solids Building
  • Install reinforcing steel and concrete for the Biologically Activated Filter (BAF) Building walls and elevated slabs
  • Install mechanical process piping in the Biologically Activated Filter Building
  • Continue mechanical, electrical, plumbing, HVAC, and masonry activities in the Grit Building and Grit Chambers
  • Install underground process piping throughout the site
  • Export excavated materials off site



  • Start Date: September 2016
  • BAF Substantial Completion: December 2019
  • Secondary Permit Compliance: April 2020
  • Project Substantial Completion: May 2020
  • Final Completion: August 2020
  • Project Construction Costs:
  • Design Engineer: AECOM
  • General Contractor: Methuen Construction
  • Design Flow: 6.1 MGD average
  • New Treatment Processes:
    • New Headworks
    • Biologically aerated/anoxic filter (BAF) using the Kruger BioSTYR ™ technology for Secondary Treatment and Nitrogen Removal
    • Rotary screw presses for solids dewatering
    • Simplified Process Flow Schematic

Map of Project Area


Map of Peirce Island Project Area


Designated Map of Construction Traffic Route


Designated Map of Construction Traffic Route