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Customer: Watercare Services Ltd Contract type: Construct only Location: Auckland, New Zealand   |
Fast Facts
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McConnell Dowell’s Mechanical Division has a long history of delivering asset upgrades and renewals at the Māngere Wastewater Treatment Plant, and late last year, Watercare awarded the team the contract to upgrade Digester 8.
The Digester 8 Tank is one of eight mesophilic anaerobic digester tanks at the plant where wastewater is stored. Bacteria break down the organic matter inside this pressure vessel as part of the wastewater treatment process. The project's scope of work includes:
- Inspecting and repairing pipes and fittings inside the tank
- Creating a safe access platform for valve maintenance
- Replacing the roof
- Constructing a foundation slab suitable for lifting
- Designing and installing a support system for the emergency shutdown pipes
- Repairs to the internal scaffolding and surfaces
The aim is to improve and extend the digester's working life, which, when regularly maintained, can last up to 50 years.
Some of the work scope, including the removal of the old roof, has already been completed. The old materials from the roof were recycled wherever possible, and approximately 100 tonnes of steel were crushed for reuse. The focus on sustainable construction methods at the Digester 8 Upgrade has resulted in the recycling of 150 tonnes of steel to date.
The reduce, reuse, recycle philosophy has diverted approximately 98% of the waste on the project from landfills, surpassing the company-wide target of 90% and aligning with Watercare’s sustainability policy.
The planned upgrade is scheduled to be completed at the end of 2026.
