Case Studies: Trenchless Sewer Rehabilitation in River Valley Lands (York Durham Sewage System and Toronto Albion Sanitary Trunk Sewer Rehabilitation Projects)

摘要

As underground infrastructure in the Greater Toronto Area ages, municipalities are commencing large-scale rehabilitation programs to extend the service lives of their sewage collection systems. Trenchless methods are typically preferred to rehabilitate aging infrastructure installed in areas that are located in protected forests, parklands, and archaeological areas-of-potential. This paper will examine two large diameter sewer systems requiring trenchless rehabilitation; the York-Durham Sewage System (YDSS), and the Toronto Albion Sanitary Trunk Sewer (STS). The YDSS and Albion STS are wastewater collection systems constructed in the 1970s and 1960s, respectively. The YDSS ranges in diameter from 525mm to 1350mm, while the Albion STS is 750mm in diameter for the entire length. After thorough CCTV investigations, both systems identified several locations that were subject to severe infiltration or structural deficiency that require rehabilitation. For the Albion STS, an Environmental Assessment was completed in 2015 and directed the detailed design towards a combination of abandonment, rehabilitation, and complete flow diversion to a larger trunk sanitary sewer.