On Sunday (subs note: November 10), Piper – a tunnel-boring machine – completed the final leg of her journey to install a five-kilometre-long pipeline to transport wastewater from Warkworth to the Snells Beach Wastewater Treatment Plant.

The new pipeline is part of a broader programme of work by Watercare to improve the performance of the local wastewater network and support growth in Warkworth, Snells Beach and Algies Bay.

Watercare is investing over $300 million, which includes building a state-of-the-art wastewater treatment plant at Snells Beach.

Watercare project manager Dirk Du Plessis says the pipeline was tunnelled in three stages, with the last stage being the shortest and easiest for Piper to complete.

“On her final leg, Piper went headfirst, mostly downhill, to tunnel through consistent but hard ground.

“Unlike the other two legs, her third leg had no curves on it – making things a bit easier and faster.

“Throughout her journey, Piper used her face to devour a smorgasbord of various soft and hard ground that were transported out of the tunnel and separated from the water at a dedicated separation plant at the launchpad.

“At the separation plant, the ground material is separated and water is pumped back to Piper to transport much-needed bentonite for lubrication and for pumping tailings back to the surface.

“Since September of last year, Piper has been installing the pipeline at a rate of about 36 meters per day.”

Watercare senior project engineer AJ Jaafar says despite Piper breaking down twice on her 14-month journey, the installation of the pipeline has gone rather smoothly.

“Between each leg, a dedicated McConnell Dowell crew would spend two to three months getting her ready to go.

“During this time, the crew would give her a good pampering: washing and checking her hydraulics, motors, and navigation systems, as well as replacing worn-out seals and mechanical parts or broken equipment damaged from her last leg.

“Plus, it also gave the crew time to set up the equipment at each new launch site and do final checks and balances before starting each leg.

“Once she’s tunnelling up to 50 metres underground, it’s almost impossible to get her out for repairs without causing damage and delays to the project.

Jaafar says once Piper completes this final leg, she will undergo a full maintenance check.

“After Piper gets a clean bill of health, she will move onto her next job with her own dedicated drive crew.

“Our next major milestone for the project is to backfill the drive sites and to connect the pipeline into the Lucy Moore Wastewater Pump Station and Snells Beach Wastewater Treatment Plant.

“After that, this pipeline will be brought into service at the same time as the pump station and treatment plant, which is scheduled to be in service by mid to late 2025.”

Update on the Snells Wastewater Treatment Plant

More than 120 workers are diligently working to complete the mechanical and electrical installation at the Snells Beach Wastewater Treatment Plant.

Watercare project manager Casper Kruger says the crews have livened the motor control centre recently, permanently connecting the plant to the local power network.

“Achieving this required a coordinated effort between the contractor, power supplier, and electrical inspector following months of preparation and planning.”

Kruger says the teams focus is on completing key elements of the plant in preparation for commissioning in 2025.

In the coming weeks, our crews will be finishing up the installation of the outfall tanks and UV systems, as well as having the process water in place for the cold commissioning start in early 2025.

“The completion of our control building is another key element of the plant that will shortly be fitted out to enable the cold commissioning to begin.”

Kruger says cold commissioning is a crucial step to ensure the plant operates smoothly and safely.

“This process involves testing and verifying the plant’s electrical and mechanical equipment, as well as treatment systems, without introducing wastewater into the system.

This phase is essential for identifying and rectifying potential problems early, reducing the risk of operational failures, and ensuring compliance with regulatory standards.

The Snells Beach Wastewater Treatment Plant is on track to be brought back into service by mid to late 2025.”

Currently, the two wastewater treatment plants at Warkworth and Snells Beach serve a population of around 8,500 people. The new plant will be able to serve 18,000 people initially and will undergo staged upgrades as required to serve up to 35,000 people.

© Scoop Media