In response to concerns from DEQ that the city of Newberg’s winter flows and total solids may be approaching untenable levels due to population growth the city is looking at adding a third oxidation ditch to the water treatment plant. It’s worth noting that the city has never had a discharge into the river unlike other nearby communities.
This will entail a very major expense since it would require upsizing many parts of the existing waste water plants infrastructure including addition capacity for clarifiers and solids handling. Scoping work is occurring right now, but the cost is likely to be north of $30M. A wastewater capacity study was completed in April of 2025 to assess the need for this upgrade.
There are documents below related to this project its history and for full transparency documents connected to the upcoming request for proposal (RFP) to obtain proposals to carry out this critical task.
Documents Connected to the Oxidation Ditch and Capacity Study
Here a list of downloadable documents connected to the Wastewater Treatment Plant (WWTP) and recent studies to discover its capacity status and future needs.
The recent capacity study from February of 2026 that points to the need for major upgrades to our WWTP system can be downloaded from here.
Here are as built documents for download as examples of our current secondary clarifier and oxidation ditch installations:
Oxidation ditch
Secondary clarifier
RFP and RFP Questions and Answers
Items connected to the upcoming RFP will be posted below (If approved by the City Council this spring).
