The Perils of Interceptor Surcharging: Unintended Consequences of In-line Storage
Andrew W Peters · Proceedings of the Water Environment Federation · 2023
The Perils of Interceptor Surcharging: Unintended Consequences of In-line StorageAbstractUtilities are increasingly frequently resorting to real-time control systems that intentionally block the flows in interceptors to take advantage of available in-line storage during storm surges events to combat sewer overflows from sewers. Many utilities are also increasingly frequently extending their pump station’s wet wells into the sewers feeding the wet well to raise net positive suction head to improve pump performance and to effectively enlarge their wet wells, improving pump performance. When hydraulic grade lines subside to normal (open channel) operating levels, the any sewage pushed outside the pipes through defects and failed joint seals/gaskets pours back into the pipe, bringing bedding fines that eventually result in pipe bedding envelope failure and pipe collapse. This paper identifies the causes, mechanisms of failure, evidence of failure caused by surcharges, inspection techniques to identify pipes at risk if surcharged, and rehabilitation methods once a pipe is thus compromised using the case study of the Howard Rossa Interceptor in Evansville, Indiana as an illustration of cause and effect.Real-time control systems that intentionally block flows in interceptors pressurize pipe. In pipes with failed joints (which encompass many interceptors in this situation), the wastewater is pushed outside the pipe. When flows return to normal, the wastewater stored in bedding returns to the interceptor, carrying fines that eventually cause pipe the fail dramatically. Mechanisms of failure, evidence of likely failure, inspection techniques, and rehab methods are discussed.SpeakerShelton, JamesPresentation time11:00:0011:30:00Session time10:30:0012:00:00SessionBAP Tunnels and InterceptorsSession locationRoom S504a - Level 5TopicCollection Systems, Intermediate LevelTopicCollection Systems, Intermediate LevelAuthor(s)Shelton, James WAuthor(s)J. Shelton 1; A. Peters 2 ; J. Shelton 1;Author affiliation(s)Arcadis 1; Evansville Water and Sewer Utility 2 ; 1;SourceProceedings of the Water Environment FederationDocument typeConference PaperPublisherWater Environment FederationPrint publication date Oct 2023DOI10.2175/193864718825159169Volume / Issue Content sourceWEFTECCopyright2023Word count11