Willapa Regional Wastewater Facilities

Rognlin's constructed this new 2.9 MGD wastewater treatment plant on the same site as the existing plant. Major components in Schedule A of this project included a new 20-inch influent pressure line under the Willapa River to the new treatment plant and a new 10-inch influent pressure line from Raymond Pump Station No. l to the new treatment plant. Schedule B of this project included conveyance facilities between the existing South Bend Pump Station No. 3 and the new Willapa River Crossing consisting of approximately 12,900 linear feet of 16-inch HDPE pipe, 530 linear feet of 8-inch PVC pipe, 355 linear feet of 20-inch HDPL pipe, valve vaults, manholes, and pump station work.

The new plant also included a variety of different systems and buildings including a new leachate/vactor truck dump station, a new pile-supported headworks with six-millimeter fine screens, a screenings washer compactor, aerated grit chambers, two pile-supported aeration basins, two pile-supported circular secondary clarifiers, an equipment building with process air blowers, chemical feed systems, return activated sludge pumps, non-potable water pumps, scum pumps, waste activated sludge pumps, thickened sludge pumps, digested waste activated sludge pumps and a rotary screen thickener, two pile-supported aerobic digesters, a pile supported lime storage and addition system, two pile-supported digested sludge storage tanks, a pile-supported solids handling building with sludge recirculation and feed pumps, a sludge heat pasteurization and dewatering system, electric steam boiler, and sludge conveyor, a scum holding vault, a plant drain pump station, an aeration basin drain pump station, a stormwater treatment system and pump station, a diesel fuel storage system, a control building with laboratory, and modifications to the existing control building, existing generator building and existing blower building.