Portage City hears final-design update on wastewater plant; estimated cost about $55 million

PORTAGE CITY — The Portage City Council received a final-design and cost update on its wastewater treatment plant overhaul on Tuesday night from Strand Associates, which recommended replacing the plant’s rotating biological contactors with oxidation ditches, adding class A dried biosolids processing and other mechanical and electrical upgrades to meet new discharge limits and to address aging infrastructure.

Strand Associates engineer Randy Lehner said the firm’s current planning estimate places the total project cost “in that $55,000,000 range,” and outlined a multi-year schedule that would submit design documents to the Wisconsin Department of Natural Resources (DNR) in April, advertise for bids in July, open bids in August and aim for construction completion in mid-to-late 2028.

The project responds to coming WPDES permit phosphorus limits from the Wisconsin DNR and to equipment that dates from the plant’s original 1980 construction. Phil Livingston, a city staff member who opened the presentation, told the council that the city contracted Strand in 2021 and that “Strand has been a great asset to our utility department.”

Why it matters: Council members and staff said the plan will affect long-term compliance obligations and the utility’s finances. City staff engaged financial adviser Ehlers and signaled that future rate increases and debt structure will be discussed separately; Strand and staff said the city may be eligible for up to $3,000,000 in principal forgiveness from state funding programs.

Key design elements and operational implications

- Process changes: The design replaces the existing rotating biological contactors (RBCs) with oxidation…