Peak Excess Flow Treatment Facility, PEFTF

The Peak Excess Flow Treatment Facility (PEFTF) is being developed as a result of the recommendation in the Willow Lake Wastewater Treatment Plant Facilities Plan. This is the preferred approach to address the wet weather treatment issues facing the utility.

Peak wet weather flows up to 160 million gallons per day (mgd) will be treated within the conveyance system at the PEFTF. The proposed facility is being constructed at River Road Park, the original wastewater treatment plant site. Peak hour flows up to the conveyance system capacity of 155 mgd will be treated at the Willow Lake Water Pollution Control Facility (Willow Lake WPCF). The remote 160 mgd wet weather treatment plant at River Road Park, constructed in multiple phases, eliminates the need for conveyance improvements from River Road Park to the Willow Lake WPCF. The initial phase is planned for a 50 mgd capacity.

The PEFTF facility will consist of treatment processes including pumping, fine screening, high-rate clarification, and ultra-violet light disinfection. Design of the facility will include mitigation of odor, noise, and aesthetic issues, an operations area, and integration with park amenities.

The remote treatment facility proposed will be operated to prevent the capacity of the existing sewer system from being exceeded during the design storm event. It is anticipated the facility will operate fewer than ten times per year, on average. Operation events will typically range in length from a period of a few hours up to one to two days.

To meet regulatory criteria, the remote treatment facility must meet effluent limits that require secondary treatment equivalency and disinfection. Although the high-rate treatment process proposed is a proven technology for drinking water treatment, it does not have a significant history in the United States for wet weather flow treatment. To confirm the high-rate sedimentation process coupled with UV disinfection can reliably achieve the treatment goal, pilot testing was performed over a two-year period.

Questions on this project may be directed to Project Manager Clifton Serres at cserres@cityofsalem.net.

Electronic Versions

Below is a list of the documents available for this project. These documents are provided in Adobe^® Acrobat^® (*.pdf) format. The CSI specification template is provided as a Corel WordPerfect™  (*.wpd) merge document. Please click on the title to download the files.

• Final Process Conceptual Design Part 1 and Part 2
• Basis of Design Memorandum (BDM)
• BDM Drawings
• Procurement of Ultra Violet System for Peak Excess Flow Treatment Facility Specifications
• Procurement of High Rate Clarification System for Peak Excess Flow Treatment Facility Specifications
• CSI Specifications Merge Template
• NPDES Permit, 2004

Additional Information

• WLWPCF Design Standards
• WLWPCF Drawings Library