Australian-first innovation delivers unique repair solution for Hunter Water

When faced with the challenge of repairing a critical 900 millimetre water main near Newcastle, NSW, Hunter Water had two options; proceed with a traditional dig and repair method which would significantly disrupt a busy arterial road, or find a new solution.

As a utility providing drinking water, wastewater, recycled water and some stormwater services to a population of almost 600,000 people in the Lower Hunter region in NSW, Hunter Water is increasingly looking for new, more innovative ways to service its customers.

For Hunter Water it was a clear choice – innovation over impact. In the case of the 900 millimetre water main, the section needing repair was located under a busy thoroughfare, which presented a significant obstacle.

Instead of choosing a traditional dig and repair method, it proceeded with a trenchless ‘triple line’ solution using Primus Line technology. The project, which involved installing three flexible liners into the pipeline, was a first-of-its-kind for the Australian water industry, having previously only been implemented in Europe.

For Hunter Water, the decision to adopt an innovative approach has proven a win-win.

“The success of this project has been testament to the collaboration of all parties involved, both within the planning and operations teams at Hunter Water, and with our contract partners who helped us in the manufacturing and delivery,” said Executive Manager Service Delivery for Customers, Glen Robinson.

By adopting this method, Hunter Water was able to negate its main obstacle.

“Our civil maintenance crews were able to access the pipe by digging two trenches, three metres deep by seven metres long, on either side of the break location. This meant there was no need for significant road closures or traffic disruption to our community,” said Mr Robinson.

“We then enlisted the help of Interflow to install the Primus Line technology. This involved a week-long process of concurrently threading three flexible, reinforced liners into the water main from these trenches, and inflating them using compressed air.

“Using three smaller 450 millimetre liners presented us with the best option for maximising the flow capacity of the pipeline, when compared with using a single 500 millimetre liner, which would have granted us just 25 per cent of its use.

“The liners were then connected to the remaining pipeline with purpose-built manifolds. We were able to work with a local manufacturer to design and make these end fittings, which were a core component of the project.

“All up, the construction phase took just eight weeks to complete. We couldn’t have done this job without the vast number of skilled and dedicated professionals who assisted in the supply and delivery. I’d like to extend a sincere thanks to everyone involved, both Hunter Water staff, as well as contractors and suppliers.

“This project has demonstrated that innovation can open the door to new, better ways of doing things. We certainly hope to take the lessons learned from this job and see what we can take from it for future projects.”