Why New Zealand's government is investing in discarded tyres (Hint: it's about sustainability)

Wed, 2017-06-28 07:30 -- Doug Peeples

I am a firm believer of the circular economy, and its potential intersection with the smart cities movement and how it can help decouple growth from resource consumption, and environmental impact. In this post, we highlight the leadership work by New Zealand in its goal to recycle tyres into the built environment. In the smart city, efforts like this – converting waste problems into economic opportunities – need to be replicated so we can scale our chances of achieving a true circular economy. — Adam Beck

There are numerous massive tyre dumps scattered around New Zealand. And while spent tyres are supposed to be recycled, about 70 per cent of them get thrown away.

As Environment Minister Nick Smith explained in a Newshub article, "When people go to replace their tyres at their local tyre shop, they get charged five or seven bucks to recycle the tyre, but too often the tyre never gets recycled." Among the problems created are the dumped tyres attract rats and contaminants seep into soil and water.

The Government has come up with a strategy to recycle 60 per cent of the discarded tyres. There are three basic elements to the plan:

  • Large tyre dumps will be outlawed
  • Waste Management NZ will receive $6.4 million from the Government's Waste Minimisation Fund (WNF) to install tyre shredding equipment in Christchurch and Auckland
  • Most of the shredded tyres will be sent to concrete manufacturer Golden Bay Cement.

"You need to have iron as input to the cement. And at the moment we get that from beach sands on the west coast of NZ. But the steel inside the tyres actually helps provide the iron. So we'll need about half as much beach sands," Smith said.

The shredded tyres also will be used as a more environmentally-friendly fuel – to replace about 15 per cent of the coal New Zealand typically imports.

Turning rubber into roads
The WMF also is investing $460,550 another approach involving three research projects conducted by Government-owned research company Scion.

Scion scientists are investigating if it will be possible to undo the vulcanising process that turns raw rubber into durable tyres. If they can, the rubber may be used as a high-performance binder for roads or as an additive in thermoplastics.

They’re also looking at the potential for integrating the waste rubber into building materials such as flooring that would create a sound barrier. And the third project is focussed on assessing how the rubber could be used in wood panel manufacturing as a component that would reduce noise and vibration.

"Finding solutions to this environmental challenge is well within our research capabilities and the results are already very promising," said Elspeth MacRae, Scion's general manager for manufacturing and bioproducts.

Doug Peeples is a writer specializing in technology and energy. Follow @smartcitiesanz on Twitter.