This week, Cat Turner, secretary of IoM Friends of the Earth, finds that creative recycling can give even old tyres a rebirth.
Used tyres: not the most inspiring candidate for recycling, you’d think – but with a little imagination, they can get used for all sorts of things. Farmers use them for weighting down tarpaulins, low carbon builders fill them with rammed earth to make beautiful and liveable homes known as ‘earthships’, and lots and lots of people use them as planters.
I can recall seeing Laxey school put small columns of them to great use as raised potato beds, easily dismantled when the children needed to harvest their produce.
All commendable stuff, but not really making big inroads into the huge numbers discarded every day of the year, the world over.
And there are billions of them, amassing in stockpiles all over the place.
To be sure, the situation’s improving. Back in 1990, only about 17 per cent of the tyres discarded each year were reprocessed into something else of use (including energy, when burned in power plants).
That number has improved massively – nowadays, around 80 per cent of the world’s discarded tyres end up being ‘chipped’ into rubber granules and chunks, for use in playgrounds (the nice squishy-but-firm surface your child lands on after plummeting from the climbing frame), combined into aspalt, made into low-grade rubber materials or burned as a low-cost fuel.
Now, however, the stuff’s finding its way into much higher-value products.
This is because after being flash-frozen and then pulverized into a fine powder, the rubber from old tyres can be a valuable (but cheap – really cheap – and clean) ingredient in just about everything you can think of, from plastics to automobile parts.
It’s great news – in part because it lowers the cost of stuff, but mostly because it saves having to get more oil out of the ground to make those products, and so helps make a significant dent in the world’s carbon footprint.
And that’s crucial, as the effects of climate change begin to really hurt the world’s economies and ecologies.
It’s a double-win for the environment too, being an example of what’s known as ‘closed-loop’ industrial system thinking.
This sounds complicated, but it’s just the term used for any production system in which the waste or byproduct of one process/product gets used to make something else.
Industrial ecosystems thinking is a way of comparing commercial production systems to what’s going on in the biosphere, and trying to learn from it and work in sympathy with it, and closed loop production is an elegant example of it at its best – just as in the natural environment, plant material gets eaten by animals, and the resulting animal waste ends up fertilizing the soil that in return nourishes the plants.
Tyres might look dull and utilitarian – but tyre rubber is actually a pretty sophisticated blend of natural and synthetic rubbers, plus something like a dozen other chemicals.
If you see it as a low-grade, low-tech commodity, then its worthwhile uses are quite limited and low value (ie, the planters and playground surfaces we spoke about before).
But once you take a closer look at what tyres are actually made of (ie, they’re a brilliant cheap source of complex polymers), they become much more interesting. Using the methods I mentioned above, it’s possible to convert them into amazingly fine powders – as small as 50 microns, which is narrower than a human hair – for making everything from plastics to automobile parts, significantly more cheaply than is the case where those things are derived from natural or synthetic rubber.
And eventually, of course, the goal is to ‘close the loop’ on old tyres.
One company involved in this process is Lehigh Technologies.
Lehigh has created a micronized rubber powder out of old tyres, by first freezing them with liquid nitrogen and then running them through what amounts to a ‘turbo jet engine with teeth,’ as the company’s CEO, Alan Barton describes it.
Lehigh is using this ‘cryogenic turbo mill’ to make what it thinks are the finest powders yet from old tyres, to create valuable new material at low cost and with minimal environmental impacts.
The recycled material goes into new products which would otherwise require new oil to make them – thus significantly cutting the greenhouse gas emissions which are involved in their manufacture. Good result!
So far, Lehigh says it has put some 150 million new tyres back on the road (composed of 10 per cent old tyres), and it’s aiming to get into providing materials for roads, construction materials, shoes and plastics.
As the cost of many resources spirals, and the environmental impact of sourcing them gets ever more damaging, we may find that mining waste for new materials becomes our most abundant option.
Let’s hope 2013 is the year of closed loop innovation!