A crew member walks on the inside of an underground sewer tunnel

Wastewater Facility Settled Sewage Pipe SIPP

During a review of the San Jose-Santa Clara Regional Wastewater Facility, severe crown corrosion was found inside critical 96-inch and 87 by 136-inch settled sewage pipe constructed in 1961. According to expert estimations, the probability of failure of the interior of the pipelines was 80-100%, with a remaining service life rating of 0-12 years and probability of failure of the exterior of pipelines 40-60% with a remaining service life of 24-36 years.

The Michels Trenchless, Inc. crew performed a variety of work to rehabilitate 541 feet of the 96-inch round pipe and 380 feet of the 87 by 136-inch pipe, started with cleaning. The crew completed the over-the-hole wet-out of a cured-in-place pipe (CIPP) liner on the round pipe. From the installation of the liner to cool-down of the heated water, the installation process of the 96-inch CIPP liner took 80 consecutive hours.

The crew used rebar and concrete to repair the damaged crown on the other pipe, sprayed geopolymer mortar to restore the crown to size, and completed a spray-in-place pipe (SIPP) application of an epoxy liner to rehabilitate the remainder of the pipe.