Dr. Anumitra Mirti, an environmental and climate resilience specialist and Beca’s newly appointed sustainability advisor, shares her insights on the state of circular economy in the roads and infrastructure sector. Written by Tara Hamid, Roads & Infrastructure Australia magazine.
Dr. Anumitra Mirti joined Beca earlier this year to lead the group’s first dedicated decarbonisation and sustainability advisory service in Australia. 

As a researcher with the University of New South Wales, she has studied the impact of climate change and extreme weather events on infrastructure health. In her former capacity as Strategic Environmental Planning Manager for the Central Coast Council in New South Wales, she has helped deliver projects on climate change, sustainability, disaster resilience and greening visions. 

She is now excited about the prospect of helping implement circular economy frameworks through projects and initiatives led by Beca. More broadly, she’s invested in creating a wider impact on the industry by helping facilitate decarbonisation strategies for Beca’s clients.

"Infrastructure projects are responsible for 70 per cent of Australia’s annual greenhouse gas emissions."

“I want to make real impact on the ground, and to eradicate the narrowness in thinking,” she tells Roads & Infrastructure magazine. 

As one of Asia Pacific’s largest independent advisory, design and engineering consultancies, Beca helps deliver major road, highway, railway, bridge and airport projects within the region. As such, the group’s initiatives have a high impact on the market and the rest of the industry.

“At Beca, we have a sustainability strategy, which focuses on both Beca’s performance – which we call our footprint, as well as on how we create impact in the market – which we refer to as our handprint,” says Mirti. 

“I joined Beca because of the opportunity to influence across sectors. Beca is at the forefront of delivering critical infrastructure projects, so I believe Beca’s role is to be part of the solution, working with upstream and downstream clients to facilitate conversations around decarbonisation.”

It is through this advisory role that Mirti is looking to generate collective impact on moving the infrastructure sector towards circularity. The first step, she says, is acknowledging that the pace of change needs to accelerate. 

“Infrastructure projects are responsible for 70 per cent of Australia’s annual greenhouse gas emissions. With hundreds of billions of dollars committed to infrastructure and construction projects, there’s a real opportunity for us to be innovative and bring new ideas into the future. This is the least advanced area where we can facilitate net zero thinking and meet our goal of limiting global warming to below 1.5 degrees Celsius,” she says.

And yet, major hurdles remain on the way, particularly with respect to the use of secondary construction materials that have zero, or lower, greenhouse gas emissions.

Impact of materials

The steel, cement and aluminium industries each produce about seven to nine per cent of annual global greenhouse emissions. This embodied carbon is in addition to emissions produced in the process of transporting materials to project sites.

Cement, as one of the key ingredients of any construction project, remains highly carbon intensive. The burning of limestone to create quicklime – a key ingredient of cement – released significant amount of carbon dioxide into the atmosphere, leading to direct emissions from cement production. 

“Forget about everything else. If we continue to use cement, we are not going to be able to meet our target for 2050,” says Mirti.

"If we continue to use cement, we are not going to be able to meet our target for 2050."

Realising the need for construction materials to align with net zero carbon targets, the World Wide Fund (WWF) last year initiated the formation of Materials and Embodied Carbon Leaders’ Alliance (MECLA), which is supported by the New South Wales Government’s Department of Planning, Industry and Environment. The goal of MECLA is to bring different sectors together across the building and construction supply chain to gain a better understanding of barriers to uptake.

Observing that the initiative is a “good start for bringing industry together,” Mirti says finding green substitutes for construction materials requires a systemic approach to overcome barriers from a legislative and technical perspective. 

“Take the case of Beca for example. As a company delivering critical infrastructure, Beca’s goal is to implement infrastructure that utilise products with low carbon intensity. On the supply side, we buy material locally wherever possible to reduce our carbon footprint. Likewise, when we deliver an asset for our client, we want to make sure that we are delivering a net zero service to them so that we are not putting the burden on the client to continue with emissions from that project. But our decisions can be compromised by what is available in terms of policy framework.”  

Searching for alternative materials

With some key construction materials in short supply – either in the short, medium or long term – access to clean secondary material is another issue Mirti says the sector needs to consider.

“Fly ash is fast become a secondary material to make cement and maintaining our roads. But as a by-product of coal production, access to fly ash will be limited in the coming years when coal mines in Australia close eventually,” says Mirti.

Infrastructure projects are responsible for 70 per cent of Australia’s annual greenhouse gas emissions.
“A parliamentary inquiry conducted last year found that in New South Wales alone, we have about 200 million tonnes of fly ash stored just in the Hunter Region. But most of this fly ash is not the clean material used for cement production, rather it’s coal ash, which is a toxic waste. So, we might only have access to clean fly ash for less than ten years or so, unless you import it at premium price and high carbon footprint.”

While there have been positive strides in recent years to incorporate recycled material into infrastructure projects, Mirti says the knowhow is still at its infancy.

“While we have dipped our toes into re-purposing waste material such as glass and soft plastic in infrastructure – a process that was accelerated following the 2017 waste import ban from China – we are still at the beginning of that learning curve. While countries in northern America and Europe are moving much faster, we are strolling. We need a leapfrog approach to fast-track the transition to circularity,” she says.

“It’s positive to see local, state and federal governments testing low-carbon materials and recycled materials in road designs. But to move beyond these trials, technical specification is required. Currently, we are at the juncture of building that knowhow. With innovation funds flowing from state and federal governments, together with the backing of our academic sector and the data available from local trials and from other countries, we can mobilise that transition.”

The missing ingredient

Mirti says it’s promising to see a growing appetite for circularity in infrastructure projects, especially within roads and transport. The missing ingredient, she says, is the urgency to fast-track implementation by creating the right mechanisms.

“As of last year, all of our states had come up with very strong policy positions. The New South Wales Government’s Waste and Sustainable Materials Strategy sets strong directions for secondary material use. Queensland’s Waste Management Resource Recovery Strategy provides a framework for the state to become a zero-waste society,” she says.

“Victoria is leading in this space, being the first government to create a Circular Economy Act in 2021. Another good example from a circular economy perspective is from Geelong, which was the first Australian city to provide an innovative procurement model for 100-year maintenance-free pedestrian bridges,” she adds.

The next step, she observes, is for all key stakeholders to come together to create collective knowledge of how to transition from the trial phase to implementation phase.

"We need to re-think the entire system. Everyone is still working in silos and the overall approach so far has been reactive rather than proactive.”

“Implementing circular economy is complex, because currently in Australia we are trying to fit circular solutions into a linear system and it’s not going to work. We need to re-think the entire system. Everyone is still working in silos and the overall approach so far has been reactive rather than proactive,” she observes.

“Positive change is happening across the sector, but so far, it’s been moving more like a tornado, making only partial and localised impact. If we want to leap forward, we need to move collectively like a cyclone.” 

This article was originally published in the April edition of Roads & Infrastructure Australia magazine. To read the magazine, click here.