Large diameter sanitary sewer interceptors are often the backbone of a collection system and many utilities are faced with thernchallenge of rehabilitating them as they approach the end of their design life. Due to the critical nature of these interceptors,rnaccess may be restricted, cleaning may be difficult, and bypass pumping may be unfeasible. This paper will present the methodsrnand design considerations for these difficult cases with project examples that include rehabilitation of a live sanitary sewerrntunnel using commercial divers. The objectives were to identify construction projects that were: A) Fully utilizing the currentrnstate of trenchless technology, B) Cost-effective, and C) Attractive to contractors for increased competition during bidding.rnProject challenges included: complex bypass pumping restrictions through creeks and wetlands, up to 60% accumulated debrisrnin 78-inch interceptors, and a limited construction season window.
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