They ve taken a real complex thing and made it fairly simple to set up. That s what I like about it. The TriCities plant treats sewage from Gladstone, Oregon City, and West Linn, Oregon. They ve recently added a diversion from the Clackamas area. Volume runs as low as 3 million gallons a day during the summer and averages 10-12 million gallons per day in the winter.
Sewage is processed through screens, digestors and aeration basins.
Sludge from the digestors is hauled away for application on grass and hay fields. Effluent is chlorinated and dechlorinated before being dumped in the Willamette River. We re supposed to have minimal or no impact on the river. Rainfall is the most important weather parameter for treatment plant operations. They use rainfall data to anticipate increased flows and modify the system to increase capacity.