In the sticky heat, shopkeepers soldered and fixed broken circuit boards with scraps salvaged from landfill.

The waste research scientist and engineer’s home was informally serviced by “Kabadiwallahs” — scrap dealers who would go from house-to-house collecting recyclable materials for resale.

When Professor Sahajwalla of UNSW accepted her award for the NSW Australian of the Year on Monday, she became emotional as her mind returned to these “waste warriors”.

“The waste-pickers in Mumbai who’d pick up items that can be recycled were doing one of the most important jobs,” Professor Sahajwalla said.

“And yet there’s this assumption that it’s OK that someone doing hard work is worth $12 a day.”

It’s one of the driving factors behind why she wants waste to be seen as so much more.

The Australian Research Council laureate pioneered the process of turning waste into “green materials”.

Her most notable invention is Polymer Injection Technology or “green steel”, which repurposed the carbon found in shredded tyres to replace coking coal in steel production.

This breakthrough has been patented around the world and has diverted millions of old tyres — which would otherwise take decades to decompose — from landfills.

NSW Premier Dominic Perrottet congratulated Professor Sahajwalla on her win, saying her “selfless dedication” embodied “the Australian spirit”.

But the professor remains humble.

“I wasn’t expecting the win, I remember coming up with theories on who would based on who was sitting closest to the aisle with my husband,” she said.

“This is what two nerds do.”

Recycling revolutionary

In 2018, the founding director of the Centre for Sustainable Materials Research and Technology (SMaRT Centre) at UNSW opened the world’s first e-waste microfactory on campus.

A year later, she also opened a plastics microfactory.

Piles of dissected hard drives and dusty printers are amassed at her lab-meets-factory — reminiscent of the electronics bazaars that inspired her obsession.

In a series of steps, custom-made machines — Professor Sahajwalla calls “modules” — break down the e-waste and extract valuable metals that can then be used to make other products.

A record 53.6 million metric tonnes (Mt) of electronic waste was generated worldwide in 2019, up 21 per cent in just five years, according to the UN’s Global E-waste Monitor 2020.

At the height of the pandemic, Professor Sahajwalla’s team turned the plastics from old printers into face shields for health workers at Port Macquarie Hospital.

One of her proudest moments was collaborating with Andrew Douglas, a mattress recycler operating out of Cootamundra, to produce a ceramic tile with one of her machines.

Old beer bottles and ageing mattresses were broken down and turned into tiles that have since been bought by construction giant Mirvac for use in buildings.

“It’s about creating opportunities that are fit for purpose, so maybe you have one module now that can be about $1 million dollars, then as business grows you can add more,”  Professor Sahajwalla said.

The concept does away with needing the capital to build an entire factory from scratch.

At UNSW the experimentation continues with tiles being made from school jumpers to beanies.

“It’s quite limitless if you know how to control your feedstock,” she said.

Her latest patent is a rework of her green steel invention, she describes as the “holy grail” formula by using coffee waste instead of coking coal.

Every breakthrough is still thrilling, the buzz and excitement of coming up with a new solution never gets old, she said.

“I call it the goosebumps moment and then you just want to do it again and again.”