“Sustainable sewage treatment is a step change in Melbourne Water's resource recovery ability”
Melbourne’s population is growing and the amount of sewage that the city will need to process may almost double by 2050. Melbourne Water sees this as an opportunity to increase its contribution to the circular economy as it engages in upgrading its Western Treatment Plant, where agriculture and biodiversity meet resource recovery.
The Western Treatment Plant Resource Recovery and Re-Use Complex - a joint partnership initiative between Melbourne Water and John Holland Group - will take three years to complete and will be fully operational in 2029. Dr Nerina Di Lorenzo, Melbourne Water Managing Director, discusses the utility’s planned wastewater infrastructure investments and specifically the planned capacity upgrade to the historic Western Treatment Plant, a world-leading facility in environmentally-friendly sewage treatment.
Please tell us briefly about your career path and your current role at the Melbourne Water
I’ve been with Melbourne Water now since July 2019 when I started as Executive General Manager of Service Delivery, before being appointed as Managing Director in December 2021. My formal studies include a Bachelor of Engineering, a Bachelor of Business and a PhD on the topic of organisational change. My roles have spanned the areas of Asset Management, Infrastructure Operations, Project Delivery and Business Improvement. Prior to this, I worked in the oil industry on the oil rigs in Bass Strait.
The WTP upgrade will increase its capacity by 95 bn litres per year in primary treatment to cope with Greater Melbourne’s population growth
I’ve spent over two decades in senior leadership roles, including almost five years as CEO of what is now known as Merri-bek Council. I am thoroughly committed to the delivery of the essential services Melburnians rely on today, while planning for the future.
Can you provide an overview of Melbourne Water’s planned investments in wastewater infrastructure in the coming years?
In 2022-23, we invested $303.7 million to safely manage the sewage generated by a growing city. Significant investments included the continued construction of a $200 million project that will duplicate the Hobsons Bay Main Sewer Yarra River crossing. This is all in addition to the commencement of the $333 million treatment capacity upgrade at the Western Treatment Plant (WTP).
What are the key objectives of the Western Treatment Plant upgrade, and what makes this facility unique?
This project will improve the treatment capacity of WTP, which currently treats over 60% of Melbourne’s sewage, or 200 billion litres of sewage a year. We will be increasing capacity by 95 billion litres per year in primary treatment capacity so the increased capacity will ensure the Western Treatment Plant can cope with Greater Melbourne’s increasing population, which is projected to double in population by 2050.
Further, as well as improving delivery efficiency, the projects have aided with technical innovation, sustainably modernising the way incoming sewage is treated, reducing greenhouse gas emissions, integrating food waste and enhancing the site’s methane gas production to create renewable energy.
The plant site is home to more than just sewage treatment facilities – doubling as a farm and internationally-recognised bird habitat
Established in the early 1890s, the historic WTP in Werribee is a world leader in environmentally-friendly sewage treatment, and one of Victoria’s most unlikely hidden treasures. Roughly the size of Phillip Island, the vast site is home to more than just sewage treatment facilities – doubling as a working farm and internationally-recognised bird habitat. Here, agriculture and biodiversity meet resource recovery, education and ecotourism, supporting Melbourne’s renowned liveability.
Can you tell us about resource recovery and reuse at the Western Treatment Plant?
The Resource Recovery and Re-Use Complex project is a programme of works intended to address historic and forecast growth relating to the wastewater services performed by the WTP. It transforms the WTP from a predominantly lagoon-based treatment system to a modern plant.
The project includes constructing four new key elements of the WTP, making up the Resource Recovery and Re-Use Complex: (i) a new primary treatment plant to reduce the load on existing lagoons; (ii) a sludge thickening system to minimise the water waste and thicken the sewage sludge - helping to reduce the load on existing assets; (iii) the relocation and enhancement of the existing liquid waste receival and treatment facility to improve the processing of liquid food waste to enable bioenergy production, and (iv) a sludge digestion treatment system to treat and convert a portion of all the collected sludges to reduce the plant’s odour potential.
The Resource Recovery and Re-Use Complex is a major milestone in the transformation of the WTP and will enable the rapid evolution of the site to meet the needs of the next decade and beyond. The transition to environmentally sustainable sewage treatment will deliver reductions in greenhouse gas emissions, help us to produce more renewable energy, and is a step change in our resource recovery ability at the WTP, supporting Victoria’s Circular Economy.
What are the expected environmental benefits of the planned upgrades to Melbourne’s wastewater infrastructure?
The Resource Recovery and Re-Use Complex is making significant investments in digital resources and academic partnerships to aid Melbourne Water in monitoring its scope 1, 2 and 3 emissions and ultimately reducing emissions across the works. Though laden with constructing a brand new state-of-the-art treatment works, the project bundle seeks to reduce Scope 3 carbon by at least 20% from a baseline, through a myriad of sustainability initiatives and innovations.
The new Resource Recovery and Re-Use Complex is a milestone in the transformation of the WTP to meet the needs of the next decade and beyond
Additionally, the Liquid Food Organic Waste has the potential to generate revenue and renewable power and deliver sustainable waste solutions to the circular economy.
What measures are being taken to ensure the upgraded wastewater infrastructure is resilient to climate change and extreme weather events?
The WTP is low-lying, has a flat topography and its coastal embankments are partially built on reclaimed land with only a narrow beach buffer between the site and Port Phillip Bay. This means that the site is vulnerable to coastal hazards. Climate change impacts and sea level rise are expected to exacerbate the risk of coastal hazards to the WTP’s biodiversity and sewage treatment values if no action is taken.
How will Melbourne Water fund these significant infrastructure projects, and what role, if any, will government grants or public-private partnerships play?
The multi-million dollar project is estimated to cost $711 million and is funded via Melbourne Water’s Price Submission, which is developed every five years and outlines our four proposed services across water, sewerage, waterways and drainage. It outlines the cost of delivering these services and the prices we intend to charge customers.
Our Price Submission is subject to approval by the Essential Services Commission, Victoria's independent regulator, which regularly reviews prices for water and other essential services to protect the interests of consumers.