Cessnock Wastewater Treatment Works Upgrade

Hunter Water
2021 - 2024

Abergeldie was the lead contractor to deliver a major process upgrade to the Cessnock Wastewater Treatment Plant for Hunter Water. The WWTP treats 5.8 megalitres per day and can handle wastewater from a population of up to 32,000 people. The upgrades were designed to meet future EPA requirements, through improved bio-processes in the plant and further protected local waterways.

Scope of works

The scope of work included:

  • Replacement of four existing trickling filters with a new bio batch reactor.
  • New chemical dosing systems.
  • New thickening processes for waste.
  • Power and control system upgrades.

An additional scope of works was awarded for new facilities for ferric oxide storage which included a building, new dosing skids and containment measures including double-contained pipework.

Addressing complexities efficiently 

In addition to the technical complexity of the upgrades, the team was challenged by extended periods of wet weather and disruptions to key supply chains leading to material shortages in international imports of mechanical equipment. Where possible works were delivered in parallel with the later stages of the design process, and commissioning activities were re-sequenced to get traction on areas that were completed early.

The Abergeldie team worked collaboratively with Hunter Water throughout the project and refined the process design to achieve greater efficiencies for the WWTP, which included replacing the original client design of an oxidation ditch, with a bioreactor batch.

The location of the works presented additional challenges. With the plant nearing a residential area, the access to the plant was quite tight. Strict environmental controls have helped to ensure the local creek has been protected. A proactive approach to safety and risk management onsite has helped to ensure the safety of our workers, our clients, partners and the broader community.  


Meeting EPA requirements 

The upgrade to Cessnock Wastewater Treatment Works has improved the treatment processes for the wastewater processing plant, ensuring the output of the treated water is of high quality.

The upgrades now ensure the treated water adheres to new, stricter parameters set by the EPA and cater for the projected population growth of the Cessnock local government area.