Philadelphia Water Company
Walker Diving was contracted by the Philadelphia Water Department to inspect and clean the dual siphons carrying waste water under the Schuylkill River. The fifty year old 50" x 600-ft. dual siphons were constructed with a thin steel liner encased in a concrete filled tunnel. A breach between the siphons eliminated the possibility of dewatering one siphon at a time. All work would have to be performed by divers. Diving operations were conducted utilizing fully sealed suits and helmets due to the hazardous waste water. Water depths in the siphons ranged from 55-ft. to 65-ft. with very minimal visibility. The divers initially noted the steel liner to be deteriorated and unraveling causing flow blockage. The divers removed the damage steel liner by mechanically cutting. Once the liner was removed, the siphons needed to be slip-lined. The task involved the insertion and jacking together of over 200 short lengths of 42" ID fiberglass liner pipe in each siphon. Once the liner was fully inserted and sealed at both ends, the space between the old siphon and new liner was grouted. The project was completed safely and successfully on time. Walker Diving has completed many slip-lining projects.