Newberg council authorizes RFP for major wastewater plant expansion after capacity study

Newberg City Council voted unanimously April 20 to authorize staff to initiate a request-for-proposals to design and deliver an expansion of the city’s wastewater treatment plant, after hearing a multi-part technical briefing that found existing oxidation ditches and solids-handling systems at or near capacity.

The city manager summarized results of a capacity study and invited engineering staff from Keller Associates to present the technical work. Eric Rowdy, senior process engineer for Keller Associates, said the stress test and modeling indicate the plant requires expansion to serve projected flows through the 2040s. “Based on our modeling, a third oxidation ditch and additional clarifier capacity will be required to meet future flows,” Rowdy said.

Keller staff explained a clarifier “stress test” performed last fall that allowed the city to re-rate existing clarifiers for higher throughput and avoid adding two clarifiers; staff now recommend adding one clarifier and a long oxidation ditch, along with upgrades to solids handling. John Hodkins, operations manager at the plant, said the existing tunnel-composting system is deteriorating and increasingly unable to keep pace with seasonal solids accumulation. “We’re starting to struggle right now — by the spring we start to catch up and by the summer we’re okay, but it’s trending worse,” Hodkins said, arguing that a transition to aerated static-pile handling is a lower‑cost, lower‑maintenance option.

Engineers outlined alternatives they evaluated — including drum/pelletizer dryers and paddle dryers — and recommended moving away from the existing vessel-tunnel composting to aerated static piles to reduce capital cost and operational risk. The recommended delivery method is a construction manager/general contractor (CMGC) approach, with procurement steps beginning in the third quarter of this year and construction expected to finish by the end of 2029 under the current schedule.

Finance staff and the city manager told council that the wastewater fund and system development charge (SDC) balances provide sufficient internal resources to proceed without issuing debt. The city manager said the wastewater fund had about $21.9 million in residual balance and SDC balances were projected near $15–17 million; staff projected that internal balances would not fall below roughly $10 million during the project.

Councilor discussion focused on staging, costs and the benefit of doing the work together rather than piecemeal. Without naming a mover or seconder in the record, council moved and seconded authorization to begin the RFP process; the motion passed by voice vote with all present members in favor.

The council’s authorization starts procurement steps only; final design, contract awards and any construction-phase commitments will return to the council for approval. The city manager and Keller Associates said more detailed cost estimates and alternatives analysis will be included in design-phase documents.

Next steps: staff will issue the RFP process to select an engineering firm and integrated construction delivery partner; council will receive future budget and contract approvals as design and procurement progress.