The contract also required replacement of 14 access chambers and the installation of several sections of parallel sewer to remove junctions from the main sewer. Being only 100 m away from the Swan River meant highly charged ground water conditions, which required dewatering, and the ground water had to be tested to ensure acid sulphate levels were not too high. Ensuring all of this was achieved, under the watchful eye of the Swan River Trust, meant every event and contingency needed to be considered and addressed prior to commencement of any works.

The bypassing of the sewer was critical, as one of the main issues was how to safely control and bypass the sewer flow that peaked at 250 L/sec. To enable the refurbishment works to be undertaken the 685 mm diameter RC sewer main needed to be completely isolated. With layflat seen as highly risky, and poly requiring welded joints, Drilline chose Aquamine® 300 mm diameter high impact PVC reusable pipe for this important task.

Aquamine provided a rapid, reliable and safe high pressure piping system that was easily installed and cost effective compared to other piping systems currently available. It is constructed out of a high impact PVC composite with a unique locking system that makes it virtually tamper proof when charged. The unique rubber ring and locking system also means the pipeline can handle operating pressure up to 1,100 Kpa.

Disruption to the public was also another major consideration as the 2 km long bypass pipe ran along the highly trafficked parks and foreshore of the Swan River. Drilline were able to install over 60 m of pipeline an hour, which is about the same time it would normally take to fusion weld two 6 m lengths of poly together, installing nearly 2 km of 300 mm diameter bypass line in four days.

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Drilline was so impressed with the ease, safety and cost effectiveness of the Aquamine pipe that they have become Australian distributors, investing in stock and vacuum lifting gear for easy handling and installation. With a 20-year history in the US, Aquamine pipe has been used for a range of pressure pipe applications from potable water to slurry lines on mine sites. Judging from the success Drilline has achieved, this product also has a great future in Australia.