Local crane lifts lid on Lincoln’s digester milestone

SA Water’s $18 million upgrade of the Port Lincoln Wastewater Treatment Plant at Billy Lights Point reached a major milestone this week, with the new anaerobic digester’s 20 tonne steel cover craned into place with the help of a locally-sourced mobile slew crane.

Port Lincoln business Shillabeer Crane Hire worked together with crews from South Australian company Guidera O’Connor to carefully guide the 10-metre-diameter cover on top of the digester during a 20-minute lift.

Resembling a ‘flying saucer’ while it was shifted through the air, the cover caps off the majority of the digester’s construction, which includes the structure’s round walls and installation of internal pipework.

SA Water Senior Manager Production and Treatment Lisa Hannant said safety was at the forefront of the cover lift and the team undertook significant planning in preparation.

“It’s an incredible feat and people might not be aware of the work behind-the-scenes to ensure a safe, successful operation,” Lisa said.

“The digester has been engineered to support the weight of the cover and we carried out a range of investigations to enable the lift, including compaction testing of the ground the crane sat on and an extensive bearing capacity assessment.

“Four high-grade steel chains were attached to fixing points pre-welded to the cover, while outriggers were used to stabilise the crane as it lifted our cover to the top of the eight-metre-high digester.

“The lid is actually a floating cover and sits comfortably in voids, controlled by guide rails and rollers – moving up and down depending on capacity within the digester, which is also sealed by water to prevent the escape of biogas generated during the digestion process.

“Our biogas is then extracted and burnt to provide a source of heat for the digester, helping to hold waste at a constant 38 degrees to create an optimal environment for the bacteria inside.”

Anaerobic digesters are large, sealed concrete tanks that heat the solid organic waste from sewage – known as sludge – in an oxygen-free environment, to promote the natural bacterial metabolic processes that break it down.

The new infrastructure will reduce methane emissions, and improve odour management and the long-term operability of the treatment plant.

Ms Hannant said local Port Lincoln contractors were playing a key role in the plant’s upgrade.

“With a statewide network and continuous focus on sustaining our infrastructure, there’s often opportunities to work together and support local businesses and communities,” Lisa said.

“An important part of delivering the upgrade has been working with our lead contractor, Guidera O’Connor, to identify and partner with local contractors, and to date we’ve already worked alongside seven businesses from across Port Lincoln.

“Keeping it local, where possible, can lead to a positive economic and social impact for the community we’re working within, while enabling us to tap into their expertise and knowledge for the benefit of our wider project.

“There’s around 40 full-time employees working at the plant on any given day to deliver this project and they’ve already built two pump station chambers, concrete footings and structural steelwork for new site buildings, and are now progressing our digested waste hardstand and standby storage lagoon.

“We’re proud to deliver a major project that supports residential and industrial growth in the town and will continue to keep the local community and businesses updated as we progress to the finish line.”

As part of the wider program, SA Water invested $6 million to increase the capacity of the sewerage pipe network, which included the upgrade of a wastewater pumping station and four kilometres of new sewer main around the Port Lincoln Marina.

The upgrade of SA Water’s Port Lincoln Wastewater Treatment Plant marks the final stage of the program, and is expected to be complete by December 2020.

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