Radio Australia - Innovations - Recycle Plastics To Fence Posts
21 January 2008
Recycle Plastics To Fence Posts
A process to make all waste plastics useful
DESLEY BLANCH : You probably think you're doing your bit for the
planet by recycling household waste like plastic bottles and
cartons. But in fact, most kinds of plastic are extraordinarily
hard to recycle and they end up in landfill.
Plastic in landfill can take hundreds of years to biodegrade and
burning or melting it lets off toxic gases, so it poses a real
quandary. A Melbourne business man has spent nearly a decade
figuring out how to turn the 77-thousand different types of
plastics into fence posts.
Roger Sweeney, Director of Australian Composite Technology gets
plastic waste from all over Australia. He manages to reuse
everything, from hard hats to car bumper-bars and mobile phone
The ABC's environment reporter, Claire Gorman went to meet him
recently at his production plant and just a small warning this is a
very noisy field report.
CLAIRE GORMAN : Roger, we've just walked into your factory here
and it's an enormous space and there's piles and piles of plastics
here. What's this right here in front of us?
ROGER SWEENEY : That's geo-fabrics material, which is made of
recycled Coke bottles, 99.9 per cent.
CLAIRE GORMAN : And this stuff, it actually looks like rolls of
fabric, is that going to go into your products?
ROGER SWEENEY : That's correct. It's shredded, granulated and
blended into our mixture for composite material.
CLAIRE GORMAN : What's making my head spin about being in your
factory while we've just had a quick walk around is there's
actually hundreds and hundreds of kinds of plastics here.
ROGER SWEENEY : That's right. We do just about all industrial
plastics, including cross linked polymers.
CLAIRE GORMAN : How many kinds of plastics do you recycle?
ROGER SWEENEY : We've probably lost count of the actual number,
but theoretically, our choice is up to 77-thousand.
CLAIRE GORMAN : Here on my right are piles of plastic in
bundles. What's this here?
ROGER SWEENEY : This is a waste stream from the industrial
sector which is largely polyprophylene packaging material.
CLAIRE GORMAN : So, what was this stuff of packed
ROGER SWEENEY : Nuts and bolts and equipment for manufacturing
CLAIRE GORMAN : Alright. Now we're just walking down here, and
this is a big canvas bag and it's got some chewed up pipe of some
kind in it and it's bright purple. What would that have been
ROGER SWEENEY : They're offcuts from the manufacture of plastic
water pipe, which is replacing a lot of copper in building
CLAIRE GORMAN : And, you've chewed this up ready to go into your
ROGER SWEENEY : That's correct. That plastic is cross-linked.
It's difficult to recycle, but we've been able to find a way of
CLAIRE GORMAN : That's one of the issues isn't it with all these
different plastics coming in that they are not pure plastics a lot
of them. They've got say, glues on them and metals and all kinds of
ROGER SWEENEY : That's right. The process of recycling is
becoming increasingly more difficult due to the complexities of the
CLAIRE GORMAN : And, what's this here, on our left? It looks
like -- well they're very strange shaped objects. What are
ROGER SWEENEY : Aah, that's sprues and runners from the
injection moulding industry.
CLAIRE GORMAN : What are these bright yellow things?
ROGER SWEENEY : Those bright yellow things are old chicken
crates that take chickens to market once they've been put to
CLAIRE GORMAN : So, say with a product like this, it might come
in with blood or other things on it. Is that a problem for your
ROGER SWEENEY : No, we can handle the contamination and dirt and
cardboard and other minor contaminations will go straight through
CLAIRE GORMAN : This is a crate of what used to be mobile
phones. How many of these would you get in every week?
ROGER SWEENEY : Oh, they come in by huge containers from MRI via
the Mobile Muster campaign.
CLAIRE GORMAN : What are these things up there that look like
Petrie dishes almost?
ROGER SWEENEY : They are trays that are used in the
pharmaceutical industry for making vaccines.
CLAIRE GORMAN : So, is there a danger that there might be
contamination in a case like that?
ROGER SWEENEY : No, they've been sterilised before they've been
delivered to ACT. (Australian Capital Territory)
CLAIRE GORMAN : Alright, so I'm getting the idea that you've got
masses of different kinds of plastic, including car bumpers and all
kinds of things. What's the first step in your process?
ROGER SWEENEY : Initially, when materials are received, we size
reduce it by running it through a shredding process.
CLAIRE GORMAN : And that's that massive noise in the background
ROGER SWEENEY : Well, it'll get noisier when we get closer to
CLAIRE GORMAN : This is a conveyor belt. Does this represent the
beginning of the process here?
ROGER SWEENEY : That's correct. This reduces the large objects
such as bumper bars down to a manageable size, for further
CLAIRE GORMAN : I'm looking at the vast array of stuff you've
got here. I'm wondering does anything go back into landfill?
ROGER SWEENEY : It does. Our recovery rate is for every one
hundred and four 30 cubic metre skips are processed, we send one
skip to landfill, so it's less than one per cent of material is
CLAIRE GORMAN : This stuff here comes from Canberra, does
ROGER SWEENEY : That's right. That comes from Parkwood Recycling
Centre, that is all the building waste, plastics from all the
building activity in Canberra.
CLAIRE GORMAN : What made you want to do a job like this, where
you're actually inventing a recipe to recycle stuff that other
people think is junk?
ROGER SWEENEY : Insanity.
CLAIRE GORMAN : I see you smile there, but you do have some
significant challenges, don't you?
ROGER SWEENEY : Well, we do. The way forward in the environment
is to actually do something. You can't just sit on your hands and
talk about it. You've actually got to get out. Invested in here is
around eight million dollar investment and it probably needs twice
as much again to make a real impact. So, I think time for talking
is finished. This is part of the doing of the doing.
CLAIRE GORMAN : You must have had to put a big R&D
investment in that though?
ROGER SWEENEY : We spent nine years researching it before we set
CLAIRE GORMAN : What's happening here in front of us?
ROGER SWEENEY : This material is going through a granulation
process to reduce it in size and then it's being re-densified back
into pellets to make it usable in our process.
CLAIRE GORMAN : Is this the next stage from what we just
ROGER SWEENEY : That's correct. This is the next size reduction,
and in this case, because it's light plastics, it's being
redensified to give it some mass, so it can be used in the
extrusion process, which we will see shortly.
CLAIRE GORMAN : So this stuff coming out there that you've got
in your hand is very fine?
ROGER SWEENEY : That's right, and it's very heavy, which enables
it to have some critical mass to able to be blended with the other
hard plastics to use in the composite process.
CLAIRE GORMAN : I was just laughing before because you've got
these massive posters here of Australian Open tennis stars. What
are these doing here?
ROGER SWEENEY : We do the recycling of plastics for shows like
the Australian Tennis Open and these signs and posters and pictures
and billboards happen to be made of plastic. It's a polypropylene
and we also re-shred them. We kept a few of these as a bit of a
CLAIRE GORMAN : So are you telling me you're going to mince up
our Australian Open tennis stars?
ROGER SWEENEY : That's right and some of them should be minced
up too, I can assure you.
CLAIRE GORMAN : Compared to some of your other equipment, this
machine in front of us looks a little bit insignificant, but in
fact it's not.
ROGER SWEENEY : It's where the excitement starts in the
This machine is a ribbon blender that takes all that material
you've seen being shredded and granulated and blends it into the
successful formula to make a fence post in a very consistent
CLAIRE GORMAN : What would happen if the formula wasn't
ROGER SWEENEY : The post would get rejected under quality
control and we'd have to shred them and start the whole process
CLAIRE GORMAN : And weight is important too?
ROGER SWEENEY : This machine weighs it as it goes along. It's on
its own pedestal with its own scales and we can tell absolutely to
the kilogram as to what blends of material are in it.
CLAIRE GORMAN : I just climbed up the ladder there and had a
look in and it looks a little bit like a breadmaker.
ROGER SWEENEY : That's exactly right. Just like when you Mum
made a cake. If you didn't put sufficient flour in, or too much
flour or not enough currants or whatever, the recipe wouldn't come
CLAIRE GORMAN : I bet you've done that a few times?
ROGER SWEENEY : Many thousands.
CLAIRE GORMAN : You've got a handful of metal there. What's
ROGER SWEENEY : In the system, we have ten zones that remove
metal from the plastics. Even plastic that looks clean contains
metal that could be as fine as a staple, but when you're putting
thousands of tonnes a year through, it certainly builds up and you
need to have this sort of magnetic protection gates on the
The metal, it damages the extrusion equipment and it's important
that you remove as much of it as possible.
This is the actual machine that makes the fence post. The
material that you have seen processed in our walkabout today;
having been fully blended is now fed into the extruder, which
injects the hot plastic into the moulds. The moulds are then
carouselled into a water bath, cooled and then extracted and
CLAIRE GORMAN : In my mind, plastics have become a bit dangerous
when they're heated, but that doesn't happen in your process?
ROGER SWEENEY : No, we never exceed the melting point of the
DESLEY BLANCH : Roger Sweeney, Director of Australian Composite
Technology, showing ABC Canberra's environment reporter, Claire
Gorman, around his factory.