A sewer upgrade has set a national milestone as Australia’s first independently verified net-zero carbon infrastructure project. Recognised for sustainability and community impact, the project has established a new benchmark for how infrastructure can be both resilient and climate-positive.
During Ozwater’25, John Holland and Melbourne Water won the national Infrastructure Project Innovation Award – Metro (sponsored by Laing O’Rourke) at the Australian Water Awards, an accolade recognising innovative projects within the water sector that drive prosperity and sustainability.
The Hobsons Bay Main Sewer Project delivered outstanding results in the areas of sustainability, social value and community, setting new standards for best practice in the water sector.
Melbourne Water Acting Executive General Manager of Service & Asset Lifecycle Sean Hanrahan said the asset, built in the 1960s, is still a critical part of Melbourne’s sewer network, transferring around 30% of the city’s wastewater to the Western Treatment Plant.
“Nearing the end of its service life, inspections had revealed significant structural degradation, and the sewer was classified as high risk under our corporate framework, with no viable alternatives for flow diversion due to the sewer’s location underneath the Yarra River,” he said.
“There was also the potential for severe environmental and operational consequences if not upgraded. It became clear that a new, duplicate pipeline was needed to safeguard the system’s resilience. This urgency drove us to duplicate the line, while embedding Melbourne Water’s sustainability, innovation and community goals from day one.”
John Holland Environment and Sustainability Manager Keith Dimech said the project stands out due to the sustainability outcomes, which resulted from an opportunity.
“When I joined the project as Environment Manager, Melbourne Water had already set some pretty ambitious net zero targets and were looking at ways to roll those into their construction work, construction being a large contributor to overall carbon emissions,” he said.
“It was this great opportunity where both John Holland as the provider, and Melbourne Water as the client, were looking at ways to make this hundred-million-dollar project really ambitious. We asked: what could we take from other projects to make this one stand out?
“During the tender and the final negotiations, the idea came up: why don’t we try to make this project net zero or carbon neutral? It was an ambition, but we didn’t have the systems, processes or procedures in place for how to actually do it. But we found a way.”
Hanrahan said achieving net zero on the Hobsons Bay Main Sewer Project meant counting every tonne of carbon, especially elusive Scope 3 emissions from materials and spoil.
“We built the Project Pathway to Net Zero tool to track Scope 1-3 across our supply chain, offset emissions and secure Australia’s first independently verified net-zero certification,” he said.
“Along the way, we rethought sourcing, repurposed spoil and deployed 250 solar panels with battery storage for 24-hour rewewable energy onsite. It wasn’t easy, but the result was a project that not only met its environmental goals but set a new benchmark for sustainable infrastructure in Australia.”
Sustainability was also worked into both culture and contract, Hanrahan said, with circular-economy KPIs sitting alongside safety measures, and self-performed delivery enabling more intentional recruitment.
“Additionally, 50% of engineer workforce were women, well above the 13% national average. Reusing materials and avoiding landfill weren’t extras but core to delivering a project that balanced green outcomes with genuine social inclusion,” he said.
Dimech said Project Pathway to Net Zero was documented with flowcharts, tools and processes, with the intention of applying the approach further afield.
“We’ve rolled it out on my current project, which is four times bigger than Hobsons Bay. A lot of the smaller processes, like how we collect data from our sub-contractors, record it, report it to Melbourne Water, are now business-as-usual,” he said.
“We are talking about this approach with every new tender. From my perspective, it’s something we’d like to apply across many projects. It doesn’t cost extra money; it’s just a structured way of collecting and reporting data.
“At the end of the project, you’ve got really high-quality data about what materials you used, backed by delivery dockets and documentation. That makes it easier to purchase offsets, which is essential to achieving net zero, because your data is validated.”
This last point should not be underestimated, Dimech said, with offsets requiring data as proof.
“What’s really valuable is that we’ve shared this process with Melbourne Water, and they’re now encouraging other contractors to use it. It’s not just a John Holland product,” he said.
"Sustainability isn’t something we should be monetising; it’s something we should all contribute to. We’re trying to help in reducing the work involved in carbon calculations.
“Scope 3 reporting is now mandatory for most, that’s created a lot of work in the industry. So getting these systems into the industry ethos – and ideally making them free – will hopefully reduce costs for the whole water sector.”
Hanrahan said winning the Infrastructure Innovation Award means a lot to the utility, not simply for the win, but for the legacy the work will leave in the sector.
“Not just as recognition of the hard work, vision, and collaboration that went into this project – it also demonstrates that purpose-driven infrastructure is not only possible, but also powerful,” he said.
“It shows that when you lead with purpose and align around shared values, you can deliver outcomes that benefit people and the planet. Looking ahead, Hobsons Bay sets a precedent for future metro water infrastructure.
“It’s a blueprint for how we can extend beyond Environmental, Social, and Governance (ESG) principles weaving sustainable construction principles into every stage of delivery. Creating infrastructure that’s cost effective, resilient, inclusive and climate-positive.”
Know of an outstanding water project? Nominations for state and territory awards are now open.