The project involved relining six lengths of DN450 using Expanda liner, raising one access chamber, and cleaning and coating eight access chambers.

Prior to the lining works commencing, the lines were cleaned using a Recycler. To reduce cartage and use of water, the cleaning was undertaken by a one position set up incorporating two dingos positioned further up the line. The dingos were placed into position using a 100 tonne crane along with the relining Kubota to carry out the works.

Given the sewers and access chambers were located parallel to the shoreline, and on steep rocky ground, the project management team arranged for crew access to be on foot, access chambers to be well supported and equipment lifted in by crane directly above each relevant access chamber. The coatings works and sewer relining were undertaken in tandem to take advantage of the arranged closures and permits.

Significant planning and consultation with multiple stakeholders was undertaken to identify optimal relining methodology, impact to members of the public, site hazards and suitable controls, and environmental impacts.

The challenge

Six consecutive sewer pipelines were located on steep inaccessible bushland, servicing the high-profile tourist area of Mooloolaba. The parklands are maintained by the local Council and have huge numbers of pedestrians accessing the beach and park each day. Given the large area of parkland, multiple site setups were established requiring careful coordination, pedestrian management, and effective communications.

The solution

Clean the access chambers by using a single Recycler Unit with multiple dingo units placed strategically to allow jetting of a single distance of nearly 350 metres.

Reline the largest run (160 metres) of the sewer main using Expanda spiral wound liner through a bend and buried access chamber.

Recoat all access chambers using a four stage process of blasting, prime coating, rendering and epoxy top coat.

Conclusion

This project required extensive collaboration and consultation on environmental considerations identified by Unitywater and the Sunshine Coast Council to ensure that species and habitat management was a high priority resulting with minimal impact.

Flexible traffic and environmental controls were put in place due to the high pedestrian traffic which affected public footpaths and high profile tourist areas. Bog mats were used to control subsidence of equipment given softness of ground from recent rain and protection of concrete footpaths from the weight of the equipment and to minimise vegetation impact.

The project was completed on time and within budget without impact to the Unitywater network.

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