Australian Water Management Review Vol. 1 2014

Oviform Sewer Rehabilitation in the West Kembla Watertech field crews have just successfully completed a challenging contract in Western Australia. The Mount Lawley (East Perth) main sewer was scheduled for refurbishment, as well as a main sewer in Fremantle. Kembla Watertech relined these oviform sewers with UV cured CIPP lining installations. A major part of this contract was managing the sewer flows, and installing a partially unground bypass system in East Perth. Additionally, oviform patching was a major part of this contract. Patching in reticulation lines has been a day to day task at Kembla Watertech. However, field crews had to become oviform patching experts prior to starting patching work on this contract. Kembla Watertech Project Manager, Paul Propper explains, “Kembla Watertech was awarded a contract relining oviform sewer mains in Perth, Western Australia, and due to a sudden pipe collapse from deteriorated pipe before lining rehabilitation, oviform patching was required.” He continues, “Our staff successfully installed 28 oviform patches battling extreme temperatures and high UV index over two months in Perth and Fremantle.” To become experts in oviform patching, the team began an extensive period of research, where theory and existing case studies were examined. However, it soon became Figure 1: Above ground testing facility in Perth 124 | Australian water man age m e nt re v ie w evident that information regarding oviform patching was scarce, so practical testing of physical conditions would be necessary. The team designed above ground testing areas at our depot in Sydney, and on site in Perth to ensure the team had a real sense of how the conditions would impact them and began a process of trial and error to work out an efficient and successful system. A training program was then undertaken for other crew members to become proficient in the patching system. A major part of this contract was flow management. Kembla Watertech worked closely with subcontractors to develop an appropriate flow management process for this project, which involved nearly a kilometre of bypass hose in three sections, one of which was a 400 metre underground buried bypass hose to assist with road crossings. Kembla Watertech Project Manager, Paul Propper explains, “The underground bypass hose helped reduce the impact on local roadways, traffic and helped alleviate public safety concerns in a residential area.” a battle to install the patches prior to the resin curing. Shade structures were implemented to reduce the direct sunlight on both the resin and on the workers. Patches were installed early on in the shift and later on in the early evening to try to reduce the risk of curing the resin in the middle and hottest part of the day. This contract also involved installing UV cured oviform liners into 380mm x 255mm oviform sewer lines in Fremantle and East Perth. Ancillary work involved bypass coordination, removing manhole benching, lids, and step irons in order to facilitate lining equipment. Bypass installation was a huge component with a 70m bypass hose buried underground with four road crossings to prevent a major traffic control set up and to reduce public safety concerns. The project was finished in February 2014, with many customers commenting on the professional nature of the workers, and attentiveness of staff when liaising about project impacts. Kembla Watertech Managing Director, Chris Meredith, is pleased with the expertise gained by the crews and said, “The project management and field crew worked together well to complete this project seamlessly considering the challenges faced including working with a new client, management of multiple subcontractors, extreme temperatures, and having to gain expertise in oviform patching.” The physical conditions were quite extreme and with temperatures pushing 40 degrees on most days it became Figure 2: Finished product Figure 3: Above ground trial

Australian Water Management Review Vol. 1 2014 | Page 130