When the East Central Regional Water Reclamation Facility (ECR) was interested in rehabilitating existing twin 500-ft long return activated sludge (RAS) pipes, there was concern about its condition and accessibility due to a new 42-inch plant air line that was to be constructed above it. The new air line would make future access difficult and undesirable.
The ductile iron pipe, installed in the mid-1970s, carried return activated sludge at an operating pressure of 25 psi. A solution would require not only access to the space, but also be able to withstand the pressure capabilities. InsituMain® CIPP, a type of fiber-reinforced cured-in-place pipe (CIPP), was identified as a feasible rehabilitation method. The fiber-reinforced CIPP was used along with an epoxy resin to provide a structural solution as well as stand up to the corrosive nature of the RAS effluent.
The project was met with a number of challenges during the installation process including high ground water elevation and special pit placement due to aging infrastructure. To read more about the project, view the full project brief here.