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Expanding Melbourne’s wastewater treatment capacity

Reducing carbon demand for nitrogen removal with one of the world’s first full-scale shortcut nitrogen removal projects – Melbourne Water’s 5 West Nutrient Removal Plant
Melbourne Water’s 5 West Nutrient Removal Plant
Water

Over the past decade, Melbourne’s rapidly growing population has placed increasing pressure on its Western Treatment Plant (WTP) - Australia’s largest wastewater treatment facility. To meet rising demand, the challenge extended beyond simply handling more wastewater - it also needed to reduce energy requirements while modernizing treatment capacity.

Relying on conventional treatment processes to reduce effluent nitrogen would significantly increase carbon and energy demand, so we worked with Melbourne Water to develop an innovative solution that would increase capacity while satisfying their sustainability ambitions.

The result? The innovative 5 West Nutrient Removal Plant (5W NRP). Now in its integration and optimization phase, the plant has demonstrated strong shortcut nitrogen removal results.

Shortcut nitrogen removal (SCNR) via nitrite shunt: Reducing carbon needs and energy demand

SCNR via nitrite shunt is an advanced wastewater treatment process that removes nitrogen more efficiently than traditional methods. 

Normally, nitrogen removal is undertaken in two main stages:

  1. Nitrification: Ammonia is converted to nitrite and then to nitrate.
  2. Denitrification: Nitrate is converted to nitrite and then nitrogen gas, which is released into the atmosphere.

SCNR “shortcuts” this process by stopping nitrification at the nitrite stage - converting ammonia to nitrogen gas via nitrite through what's called the nitrite shunt pathway, without fully converting nitrite to nitrate.

Drawing on lessons from a successful SCNR trial conducted at WTP between 2017 and 2020, Jacobs developed the process design basis for one of the world’s first full-scale shortcut nitrogen removal plants using the nitrite shunt pathway. Leveraging advanced wastewater treatment modeling software and advanced aeration controls, the team translated the trial results into a resilient, full-scale plant.

The trial found that the 150 megaliter per day (ML/d) facility will reduce the carbon needed for nitrogen removal by ~40% and cut energy demand by ~30%. Reducing the carbon needed for nitrogen removal allows for the continued use of the anaerobic primary treatment process to divert carbon to biogas production for energy generation to generate additional renewable energy, supporting Melbourne Water’s sustainability ambitions.

Did you know?

150 ML/d

Daily treatment capacity, ~15% of Melbourne’s wastewater

 

40%

Target reduction in carbon required for nitrogen removal

30%

Target reduction in treatment energy demand

50%

Concrete reduction via Jacobs’ “donut” bioreactor tank design

Bringing the 5W NRP to life

Jacobs provided detailed design, value engineering, construction/commissioning support services and ongoing operational support for implementation and bedding down of the SNCR process at the 5W NRP. 

The design includes five 85-meter diameter precast, post-tensioned bioreactor tanks arranged in a circular “donut” around 45-meter diameter clarifiers. This circular design reduced concrete needs by ~50%, providing a lower cost of construction and reducing Scope 3 emissions, as well as improving site safety during construction.

Jacobs worked closely with Melbourne Water and the contractor, BMD, through detailed design and construction to deliver the project, and continues to support Melbourne Water in ongoing operation of the 5W NRP. 

  • This facility is a powerful example of how circular innovation can transform essential services; by treating wastewater as resource rather than a byproduct, we can create sustainable, lasting value for both our community and the environment.
    Matthew Daley
    Melbourne Water Executive General Manager Service Asset and Lifecycle said

The big picture

Jacobs’ experience in wastewater innovation and long-term collaboration with Melbourne Water enabled one of the world’s first shortcut nitrogen removal projects. 

  • Demonstrates world-leading energy and carbon efficiency in wastewater treatment.
  • Supports Port Phillip Bay health through advanced nutrient removal technology.
  • Sets a new standard for sustainable plant design and construction.
  • Demonstrates lower-carbon construction via reduced volume of concrete and use of concrete with recycled content.
  • Supports the generation of renewable energy for plant operations.
  • Supports Melbourne Water’s sustainability ambitions.

 

Awards and recognition

The 5W NRP project has received several industry recognitions for innovation and excellence including:

  • Melbourne Water’s 5 West Nutrient Removal Plant
  • Melbourne Water’s 5 West Nutrient Removal Plant
  • Melbourne Water’s 5 West Nutrient Removal Plant
  • Melbourne Water’s 5 West Nutrient Removal Plant
  • Melbourne Water’s 5 West Nutrient Removal Plant

All images courtesy of Melbourne Water