Slayden Constructors completed a major upgrade to the Lake Oswego Water Treatment Plant, expanding its capacity from 16 to 38 MGD to meet the growing water needs of the Lake Oswego Tigard Partnership. Construction was delivered in three carefully planned phases, allowing Slayden to demolish existing structures only after new facilities were fully operational resulting in zero unplanned shutdowns throughout the project.

Upgrades spanned every part of the treatment process. Work included a new 54 inch influent pipeline, raw water metering, and advanced chemical injection and rapid mixing facilities. Slayden replaced the plant’s existing sedimentation basins with ballasted flocculation, added an intermediate ozone contact basin and ozone generation system, and constructed deep bed granular activated carbon filters to replace aging media filters. The team also built a new 2.0 MG chlorine contact basin, completed water storage clearwell, and installed a new 48 inch finished water pipeline to replace the existing clearwell and pump station piping.

Additional improvements included new residuals handling systems with wash water equalization, a recycle pump station, solids thickening, and mechanical dewatering facilities. Slayden also constructed modern chemical storage and feed facilities, a new electrical building, and a new administration building to support long term plant operations.

Extensive site work rounded out the project, including yard piping, new roadways and parking areas, stormwater detention and treatment facilities, upgraded electrical service, site lighting, fencing, and landscaping. The completed expansion significantly strengthened the region’s ability to deliver safe, reliable drinking water for decades to come.