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Professor Veena Sahajwalla is passionate about rubbish.

Throughout her career, the director of the Centre for Sustainable Materials Research and Technology (SMaRT) at the University of New South Wales has been looking for ways to transform waste into something useful.

One of her greatest achievements is the invention of so-called “green steel”, the environmentally friendly technology for recycling end-of-life rubber tyres to replace coal and coke in steelmaking. It has meant that more than 2m tyres have been diverted from landfill and greenhouse gas emissions have been reduced.

In 2014 she was awarded the Australian Research Council Laureate fellowship to develop environmentally and economically sustainable micro-recycling of e-waste.

How did you end up pursuing such an offbeat, unconventional and unusual career?

Waste – and how to make the best of it – has been on Sahajwalla’s mind from a young age. “I was born in Mumbai. It’s a crazy city with a big population – 18 million people – with a big amount of waste produced and factories. I grew up in a place where there was a lot of industry and buzz around waste, and I’d walk past these factories and see all this waste, and I thought: this is what I want to do.”

It’s been an enduring passion. “Even now,” says Sahajwalla, “I look at hard rubbish and I think ‘How can you throw that out?’”

She even asked for her old battery back when she got her watch fixed. “Call me a hoarder if that’s what it takes. One time I came back to work on a Monday morning with all the chip bags that I consumed on the weekend and I saved the chip bags, because you can do something with them.”

There are deeper issues at play other than just a reluctance to throw things out. She would like to encourage everyone to rethink how they look at rubbish. “Should we look at it as a waste or should we look at it as a resource?” asks Sahajwalla.

“For us, it’s about something all of us in society are using … we can see everything as part of our lives. It’s a resource. Instead of mining below the ground for our resources, we should look above the ground. From our context, it’s a perfect win-win outcome. In a collaborative manner, we can use or share our resources.”

Sahajwalla has long worked in the traditionally masculine steel industry, but the lack of women in the sector has not been a stumbling block to her success.

“It’s an exciting domain for young people, bringing together sustainability and technology. You can be an engineer and scientist and you can work across the fields.”

Can you describe your background? 

My ambition to transform waste into valuable resources goes back to my childhood in India. Growing up in Mumbai, I used to walk past huge mountains of garbage on the way to school which supported communities of rubbish pickers. I imagined what it would take to convert “rubbish” into something more valuable, like a resource for steelmaking.

Rubbish pickers would then have something more valuable to sell and we could improve the environment and reduce costs for steelmakers. That was part of my drive to first study Material Sciences in India, and to then go onto post-graduate and post-doctoral research in Canada and later in Australia, where I have worked at the UNSW, University of New South Wales (UNSW), Australia in Sydney since the mid-1990s.

To realise this ambition, I knew that we needed to do something really significant; we needed to revolutionise recycling science.

The world’s waste mountains are packed with materials that contain valuable elements like carbon, hydrogen, silicon and metals that we would otherwise source from virgin raw materials.

That was the idea of looking at waste tyres as a potential resource — they are valuable hydrocarbons.

What do you do?

“The work that we do around recycling and waste material is really thinking about a whole new way of transforming waste. Traditionally people think about recycling waste to the same product – so plastics to plastics. When we have more complicated products, such as electronic devices, we have to think differently.”

With electronic devices, the recycling process is complicated “because there are lots of different types of materials locked into a phone or computer. So you have to think about reforming. It’s the transformation of waste to higher value products.”

Sahajwalla is working with companies in the developing world to extract maximum value from electronic waste products, and at the same time finding ways to reduce pollution and harmful health effects.

“If someone in a developing region were just after the copper, and you were a little village somewhere, you had no facilities and some of the plastics were burnt in the open air and you were breathing in the toxins and carcinogens, then a lot of these gases could be lethal.”

Can you describe a few achievements in your career?

We have have invented Polymer Injection Technology that converts old rubber tyres to metal alloys that make ‘Green Steel’ says this could be the answer to deal with the growing problem of disposal of waste tyres globally.

Waste tyres, like coke, are good sources of hydrocarbons. This means they can be usefully transformed in EAF steelmaking, as long as the process of injecting them into the furnace is precisely calibrated.