TTSA outlines $310 million 'clean water revitalization' plan to replace chemical-intensive processes

Jason Hayes, general manager of Tom and Jerry Sanitation Agency (TTSA), told the Tall City PUD board that the agency is proposing a multi-decade "clean water revitalization" project to replace aging, chemically intensive treatment systems with a membrane-bioreactor (MBR) approach.

Hayes said the plant is highly regulated for nitrogen and phosphorus and currently treats between roughly 2 million and up to 12 million gallons per day depending on season. "We are permitted for a a weekly average of 9,600,000 gallons a day," he said, drawing attention to the regulatory constraints that drove the evaluation of alternatives. He described a 50-year life-cycle cost analysis that produced a preferred MBR solution estimated to "ring in at approximately $310,000,000." Staff earlier reported a 20-year CIP estimate near $116,000,000 that has since been revised upward by later cost and scope analyses.

Hayes described several operational and safety benefits of the MBR option: substantially reduced use of hazardous chemicals (he said the project would "eliminate methanol completely" and cut sodium hypochlorite use), lower delivery‑truck traffic, and greater flexibility to meet potentially tighter future discharge limits. The project would rely more on biological nutrient removal and fine membrane filtration, which Hayes described as "state of the art" but not experimental, chosen for multi-decade maturity and reliability.

Board members and staff discussed financing and schedule. Hayes said the agency has already sold a bond tranche (a $20,000,000 tranche that produced about $25,000,000 net) and is exploring revolving funds and WIFIA financing; staff expect to complete preliminary design and have 30% design by January before pursuing major financing. On construction timing, Hayes said bidding could occur in late 2028 with construction starting spring 2029 under a design‑bid‑build approach, or earlier if a construction‑manager/general‑contractor model is used.

Why it matters: TTSA serves roughly 30,000 customers (reported as about 46,000 equivalent dwelling units capacity) and discharges to an aquifer that ultimately connects to regional waterways; the plant's performance affects water quality across the service area. The board did not take an immediate action to approve construction funding; Hayes said the presentation and supporting reports are available on the agency website for further review.