The South Interceptor Rehabilitation project is located in Renton, Washington. Inspection of this section of the South Interceptor indicated significant levels of concrete degradation and corrosion due to hydrogen sulfide. This segment of the South Interceptor is the northern most section, connecting to the Eastside Interceptor inside the Wastewater Treatment Division’s (WTD) South Treatment Plant, which is the primary influent line to the facility, conveying flows from Tukwila, South Renton, Kent, Black Diamond, Auburn, and Algona. The project will repair over 1,600 LF of severely deteriorated 72-inch and 90-inch diameter reinforced concrete sewer pipe and rehabilitate up to seven (7) maintenance holes along the South Interceptor. This work will require high-capacity sewer diversion pumping through temporary piping (both buried and above grade) and odor control at each discharge location. Multiple pipeline rehabilitation methods will be considered during alternatives analysis, seeking methods that will maximize existing capacity. Modifications to the Eastside Interceptor and South Interceptor junction structure are anticipated to isolate flows during rehabilitation. The project area is largely commercial and industrial, with the existing interceptor alignment running below Grady Way and I-405. Permitting, environmental, and property requirements will depend on the diversion alignment and relining method, and further evaluated during predesign. Close coordination with the City of Renton, WSDOT, and South Treatment Plant operations is anticipated. Refer to the Owner’s Project Criteria preliminary outline (Progressive Design Build Agreement, Exhibit A) for a complete summary of anticipated scope elements
