Council reviews capital-improvement bonding options as Tetra Tech recommends reverse osmosis for leachate treatment

City staff and consultants briefed the Riverview City Council on capital-improvement financing and the Riverview Land Preserve leachate treatment project, focusing on sample bond structures for water, sewer and road work and on a technical recommendation to install a reverse osmosis (RO) leachate-treatment system.

"So they're projecting an interest rate of about 4.25% on this project for 20 years," a finance presentation told the council while showing illustrative amortizations intended to frame how the city might bond for water and sewer mains along with associated road paving. Staff stressed the numbers were illustrative and would return to council for approval if the city advanced toward a bond sale.

The discussion of capital needs covered multiple large projects: prioritized water-main and sewer-main replacements staged over years, a "dual tunnel" project to reduce basement flooding, and a potential wastewater treatment or landfill-related facility. In staff's presentation, an illustrative water-and-sewer bond was shown at about $18 million, while a separate wastewater/landfill-related financing estimate was described at roughly $10 million. Staff said funding sources under consideration included water user fees (enterprise fund), state Act 51 road funds for the road portions, and landfill revenues or surcharges; no tax rate increase was proposed in the presentation.

On the leachate treatment item, Ari of Tetra Tech summarized technical options and recommended reverse osmosis. "PFAS... they're right now driving essentially the whole project here, unfortunately," Ari said, explaining that federal and state wastewater permitting and local limits required treatment beyond the city's existing systems. Tetra Tech reported the landfill currently generates about 100,000 gallons per day (gpd) of leachate; of that, roughly 40,000 gpd are treated for phenolics and PCBs and about 60,000 gpd are monitored and discharged without treatment under current practice.

Consultants ran pilot RO tests and reported that RO produced a clear effluent with PFAS and other regulated parameters below detection or within criteria; they said RO would provide a single, consolidated treatment train that is likely to meet anticipated future permit limits and could produce an effluent clean enough for direct discharge under the appropriate permits. A pilot produced a concentrate stream that is about 10% of influent volume; staff said while the landfill remains open the concentrate could be returned on-site to limit hauling, but after landfill closure the concentrate would require off-site disposal.

Tetra Tech and staff presented lifecycle cost comparisons. In the model used at the meeting, operating costs for an on-site RO system translated to a marginal cost of roughly 5'to'6 cents per gallon versus an assumed hauling-and-disposal cost of about 20 cents per gallon. The presentation included an estimate of about $550,000 per year the city currently pays in sewer/discharge fees to the downstream treatment authority for leachate handling; Tetra Tech said eliminating those fees would offset operating costs over time.

Consultants warned of an urgent regulatory timeline: the downstream permit limits and a local limits evaluation were expected to require compliance by the coming spring. Staff noted long lead times for key equipment (the RO skid was estimated at roughly a 10-month lead) and recommended moving forward on conceptual design, geotechnical work and major equipment specifications now to target a construction schedule that could meet the compliance timeframe.

Council members asked about concentrate disposal, potential future contaminants beyond PFAS, and whether evaporation or waste-heat approaches could reduce hauling costs; consultants said such options merit later study but were not included in the conservative cost comparison presented. The consultants also noted a potential revenue opportunity: as leachate generation declines post-closure the facility could provide treatment-as-a-service to outside generators, but that market analysis and contract terms would need separate development.

No formal bond sale or contract award was approved in the meeting. Councilmembers directed staff to continue design work, refine cost estimates and pursue funding conversations with state and federal representatives; staff said they would return with detailed financing options and required approvals before any debt issuance or construction contract.