Australian Water Management Review Vol. 1 2014

Bennelong Sewer reline – as big as it gets Kembla Watertech recently took out the ASTT Rehabilitation Project of the Year Award for its innovative CIPP rehabilitation of the Bennelong Stormwater Channel on behalf of client Sydney Water. R ehabilitation of this centuries-old system may have been the largest diameter CIPP installation in Australia – and one of the largest inversions ever in the world. The project was significant because of the age of the system that was rehabilitated (more than 150 years old); the fact that it was the first oviform combined sewer/stormwater system ever constructed in Sydney; the density of the population surrounding it; the enormous size of the channel (perhaps the largest diameter CIPP lining installation ever conducted in Australia); the thickness of the liner (35 mm); and the fact that it involved one of the largest oviform inversions ever worldwide. The project was completed in June 2012. Around 154 m of a massive 1,830 x 1,220 mm heritagelisted oviform stormwater channel was rehabilitated for Sydney Water. The pipe was relined in two inversions using CIPP installation. The access chambers had to be specially constructed for this installation, located in the middle of Sydney CBD bus lanes, near bustling Circular Quay. The liner was installed from an access chamber in Phillip Street, which is in the middle of Sydney’s CBD. The site was surrounded by major businesses, a five star hotel (the InterContinental), and was in the middle of a major bus route in downtown Sydney. This is the largest diameter CIPP lining installation ever conducted in Australia and one of the largest oviform inversions worldwide. It was an extremely difficult and labour intensive installation due to the sheer size and thickness (35 mm) of the liner. 116 | Australian water man age m e nt re v ie w Challenges faced on this project included the close proximity to residents, hotels, tourists, businesses; the proximity to Sydney’s popular tourist location Circular Quay; the physical size of the liner to be installed; the fact that the location intersected with major downtown Sydney bus routes; and the fact that the asset being rehabilitated was Heritage-listed. Lining installation Kembla Watertech used a CIPP water inversion installation. With such a significant stormwater pipe diameter, and a 1,550 mm diameter liner weighing 15 tonnes, it was an extremely difficult and labour intensive process of installation. A stormwater bypass, including construction of a brick weir, was required because of the high residual flow. Ramps over the bypass hose needed to be constructed with enough str

Australian Water Management Review Vol. 1 2014 | Page 122