Modernisation of the Lower Molonglo Wastewater Treatment Plant – Icon Water

This project concerns the modernisation and extension of the Lower Molonglo wastewater treatment plant in Canberra, in the Australian Capital Territory. Commissioned in the late 1970s, the contract includes the design and construction of a new treatment line incorporating innovative membrane filtration technology, as well as the upgrade of existing facilities. Upon completion, the plant will be able to treat up to 97 megalitres (ML) of wastewater per day. The contract is valued at AUD 385 million (EUR 236 million) and will employ up to 250 people at peak activity.

Context

The Lower Molonglo Wastewater Treatment Plant is a key piece of infrastructure in the Canberra region’s sanitation network. With population growth and increasingly stringent environmental standards in the country, it became essential to increase its treatment capacity and modernise its facilities. This project forms part of a ten-year programme initiated by Icon Water to ensure a sustainable and efficient service for the Australian Capital Territory community. It is the first site in this long-term transformation of the region’s wastewater treatment system.

Technical Aspects

The project involves the design and construction of a membrane bioreactor (MBR) capable of treating up to 97 ML/day of wastewater. Membrane filtration, the core technology of the new process, relies on very fine membranes that retain pollutants while allowing clean water to pass through, ensuring high-quality treatment and a significantly more compact facility.

The works also include the modernisation of existing equipment, aiming for long-term compatibility and efficiency. Several environmental measures are integrated into the project:

  • Use of low-carbon concrete to reduce CO2 emissions

  • Reuse of 90% of excavated or deconstructed materials on site

  • Supply of 100% renewable electricity to the site

  • Exclusive use of recycled water for construction operations

Impact

By significantly increasing the wastewater treatment capacity of the Lower Molonglo plant, the project will meet the future needs of Canberra and surrounding areas while reducing the infrastructure’s carbon footprint. It enhances the performance of the sanitation system while contributing to the territory’s ecological transition. In addition, the site will mobilise local skills, with up to 250 jobs created at peak activity, thus strengthening the regional economy.

Project Stakeholders

Client:
Icon Water (Australian Capital Territory)
Consortium:
Seymour Whyte – VINCI Construction Grands Projets
Design:
BECA HunterH2O

Key Figures

Contract value: AUD 385 million (EUR 236 million)
Post-upgrade treatment capacity: 97 ML/day
Workforce mobilisation: Up to 250 people at peak activity
Project start date: November 2025
Duration of the first project: 4 years
Programme duration: 10 years

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