Rising mains from the Nellie Street, Governor Road, Beach Street, Chelsea Park Drive and Wise Avenue pumping stations on the Mornington Peninsula have been renewed. On the Chelsea Park Drive renewal, works were completed in four days compared to an estimate of approximately 15 days for conventional construction – resulting in a saving of $200,000.
The red line in the picture above shows the route of the rising main. Imagine working in these backyards with large excavation equipment. This job was completed without entering any of the properties.
Another major challenge was the sewer rising main rehabilitation of 300 mm cast iron cement lined pipe (CICL) at Wise Avenue in Frankston. This rising main had been giving South East Water some grief over the last few years with recent failures in one backyard and along residential street. CCTV inspection indicated deterioration at several locations.
It is approx. 550 m in total length with 50 m running through the back of established properties and 80 m running under the Frankston Freeway in varied depths from 2 to 4 m.
Article continues below…The trenchless installation of 550 m, 300 mm structural, independent polyethylene pipe had to be done in six sections between 50 m and 130 m in length due to the position of the pipe. The challenge was to create least disturbance to the environment by use of no-dig technology and to complete the job as fast as possible without inconvenience to the community and freeway traffic with the sewer rising main pipe running through residential properties, streets and under the Frankston – Mornington Freeway.
Very important was also to avoid damage to properties and other existing services.
The pump station was taken off-line for 11 days with management of flows controlled by use of eductor trucks and the use of a two-way fall manhole diverting to another catchment point. The job was completed in 15 days, with actual rehabilitation lining taking only 11 days to finish.
Overall, in comparison to alternatives, the project generated huge reduction of time and, consequently, cost. Prior and during works consultation with all residents ensured that all went smoothly and ensured customer satisfaction, as alternative methods are often noisier and take much longer to complete. The pipe characteristics of flow efficiency and volume capacity have been tested after completion and the pump station set up could be retained as before.
