Orange County outlines $185 million plan to rebuild Harriman wastewater plant, schedules public hearing

Mary Beth Bianconi, partner at Delaware Engineering, D.P.C., told the Orange County Sewer District No. 1 advisory board on March 18 that the county is moving toward submitting a near-complete permit application and seeking grant and low‑cost loan programs to fund a planned expansion and upgrade of the Harriman Wastewater Treatment Plant.

Bianconi said the current design would replace Train 1 with a new 7,000,000‑gallon‑per‑day sequencing batch reactor and upgrade Train 3 “to maintain it at 3 MGD.” She told the committee the preliminary total project cost is $185,000,000 and said the estimate includes contingencies, escalation and costs for longevity and regulatory compliance. “Our current preliminary cost estimate is a hundred and $85,000,000,” she said.

The consultant said the county has completed the site survey, is scheduling asbestos and lead surveys in mid‑April for buildings planned for demolition, and expects to issue a geotechnical RFP within days. The basis‑of‑design report is nearly complete pending an updated peaking factor, and staff intend to submit a permit application this week. Bianconi said the county already submitted a variance request for total dissolved solids and chloride to the state Department of Environmental Conservation and had received only an acknowledgment as of the meeting.

Why it matters: the project is intended to address three drivers the county cited repeatedly — aging infrastructure, new regulatory requirements and anticipated future flow demand. The county is seeking a mix of grants and 0‑percent or low‑interest loans to reduce the amount each sewer customer would pay if the county instead borrowed the full cost at market rates.

Funding and rate impacts

Bianconi walked the committee through a table in the county’s map‑plan report that calculates the annual cost to a typical single‑family home under a range of grant/loan scenarios. Using conservative assumptions, the worst‑case annual cost shown in the materials is just over $1,000 per unit; the consultant said operation and maintenance and capital show roughly $500 each under that analysis. Stacking grant and low‑cost loan programs lowered the modeled annual cost to a range that Bianconi described as roughly $880 to about $1,000 per year depending on award outcomes.

She emphasized the county is pursuing federal funding from what she called the Bipartisan Infrastructure Law, described in the meeting materials as a program offering a 50% grant and 50% low‑interest loan up to $25 million per award: “This program is valuable to us,” she said, and the county wants to capture available funds in the final year of the program.

Committee members pressed for clarity about who pays these amounts. Committee members and municipal representatives reiterated the presentation and the map‑plan report apply only to properties inside Orange County Sewer District No. 1 (the village of Harriman area and parts of Monroe and the villages noted in the presentation). The consultant and staff said outside users and intermunicipal agreement (IMA) negotiations could reduce the district’s per‑unit costs and that those anticipated outside revenues were included in the offsetting revenue line in the model used for the table.

Schedule and scope

Bianconi said the county anticipates bidding construction in 2028 and estimated a roughly 24‑month construction period (with seasonal shutdowns and regulatory review potentially extending completion into 2030 or 2031): “We would bid the project in 2028, and then we would probably — you're looking at 2030, '31 depending on what time of year we do the bidding.”

Board members also debated presentation language for an upcoming public hearing the materials list for late March; the committee asked that the public presentation keep the headline numbers simple while also making clear what portion of the $185 million is expansion versus longevity, regulatory compliance and other line items. Bianconi offered to add a table from the map‑plan report to the public PowerPoint that lists the main components of the $185 million estimate.

Environmental and regulatory context

Staff and consultants said regulatory drivers shaped the project. The county has been working with the state DEC on permit renewal and sampling requirements, including emerging contaminants and site‑specific analyses; DEC had acknowledged a prior full application submitted in September 2023 and requested additional material in March 2025 that the county said it had provided. The Ramapo River, the project’s receiving water, was described as having low‑flow segments that require effluent controls that meet aquatic life standards; the project includes an upgraded discharge pipe and changes to meet the newer permit conditions.

Questions and remaining uncertainties

Committee members sought clearer public messaging on (1) what the $185 million covers, (2) how the new capacity relates to the incremental 3 MGD increase that results from going from 6 MGD to 9 MGD, and (3) how long any added capacity will serve demand before further expansion is needed. County staff said the current design replaces Train 1 with a new 7 MGD plant and explained that the site has been master‑planned to allow for future expansion up to larger capacities if needed. Staff also noted the project now integrates longevity and expansion work rather than keeping them separate because demolition and replacement reduced the scope of stand‑alone longevity upgrades.

Next steps

Staff said they will finalize the permit package and submit it, follow up with DEC on outstanding variance requests, finalize the geotechnical RFP and adjust the public hearing slide deck to better distinguish new capital costs from existing charges. The county’s materials list a public hearing in late March at 3 p.m. and additional legislative and committee actions leading to a May legislative decision to enable applications due in May.