Riser Pipe Construction for the Ashbridges Bay Treatment Plant Outfall

Author(s) K. Waher, J. Kempa-Teper, P. Rüsch, A. Solecki
Presented at: Pipelines 2023 Conference - Advancing Solutions for Resilient and Sustainable Infrastructure and Asset Management - San Antonio, Texas. Aug. 12–16, 2023.


The City of Toronto’s Ashbridges Bay Treatment Plant Outfall (ABTPO) project will be the largest wastewater treatment plant effluent outfall in Canada. This paper discusses the design approach and construction efforts for the riser pipes on the ABTPO project, including construction sequencing. Base bid marine construction performance requirements and limitations, alongside contractor-specific construction methods for all riser installation steps, are presented in the paper. Finally, the paper includes consultant and owner perspectives on challenges encountered and solutions implemented to successfully perform marine construction for ABTPO.