COMPREHENSIVE WET WEATHER TREATMENT PLANNING FOR THE CITY OF SALEM, OREGON

Wet weather treatment is an issue of high interest in many parts of the country. For the City of Salem, Oregon, wet weather is a common occurrence during the winter months, and even though the City spends 4 million per year on sewer rehabilitation and repair, SSOs discharged directly to the Willamette River occur approximately seven times per year on average. Wet-weather SSOs and ongoing wastewater treatment needs for the City are being addressed through a comprehensive planning process incorporating collection system and treatment facility planning, pilot testing, permitting, public acceptance, and financing. The recommended plan involves permitting and construction of a remote peak excess flow treatment facility (PEFTF) consisting of preliminary treatment, high-rate clarification (HRC) and ultraviolet light (UV) disinfection, rather than conveyance of all peak flows to the Willow Lake wastewater Treatment Plant (WLTP) for subsequent treatment.