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Author      Title/Abstract      


Infiltration Reduction Utilizing Flood Grouting Technology
Author: Martha Burke, Robert Jacobsen, Steve Merrill and Justin Twenter
Date: 10/12
WEFTEC 2012, New Orleans, LA, Sept. 29 – Oct. 3, 2012

The 1950s-era concrete pipe sanitary sewer system in Seattle’s Broadview neighborhood experiences significant wet weather inflow and infiltration. Intense wet weather events have resulted in sewer overflows into private residences and the environment. Previous work indicates that the majority of flow during wet weather is infiltration. For an infiltration reduction project to achieve maximum success, all components of the sewer system—mainlines, maintenance holes, and private side sewers—have to be addressed. An alternatives analysis indicated that infiltration reduction using flood grouting was the most cost-effective, least disruptive methodology. Flood grouting involves isolating and treating an entire section of the sewer system between two maintenance holes, including the side sewers, with two chemicals in separate steps. The segment is filled completely to the rim and utilizes hydrostatic pressure by the chemical fluid to apply the grout to the system. To determine the success of the project, flow meters have been installed in the system to document before and after conditions for modeling analysis. Infiltration removal rates, costs, challenges associated with working on private property, and lessons learned from this flood grouting project are documented in this paper.