Recycling Tired Tyres
Everyone who has had a vehicle for at least a few years has had the necessity to have tyres replaced whether it is replacing one through damage or multiple through wear and tear. But do any of us give a second thought to what happens to the tyre once it leaves your vehicle?
An Australian study by Hyder Consulting Pty Ltd published 30 April 2015[1] states that approximately 51 million equivalent passenger units of tyres entered the waste stream in 2013-14 which equates to around 408,000 tonnes.
Of these, approximately 5% were recovered locally (either through recycling, energy recovery or civil engineering); 32% were exported, of this 32% figure many tyres are burnt in brick and cement kilns in countries that have quite lax air pollution laws like Bangladesh, India and Thailand; approximately 16% went to licensed landfills; and 2% were stockpiled for future recovery. Approximately 14% of end-of-life tyres were categorised as having “unknown†destination, and anecdotal evidence suggests that approximately 31% of Australian tyres (predominantly large, off the road tyres) are land-filled at mining sites. That is approximately 31 million tyres entering landfill over 2013-14.
Every year millions of used tyres are dumped, whether legally or illegally. The cost of dealing with this problem rises to the millions. The dumping of tyres can also lead to severe health hazards and environmental damage.
"Even the smallest number of dumped tyres can create a dangerous breeding ground for mosquitoes that transport disease, such as Dengue Fever and the Ross River Virus."[2]
While controlling Dengue fever is a more complex issue than simply managing our waste tyres, there is little question that Australia’s poor management of waste tyres is a significant contributor. In 2007 Dengue Fever was very much a rare disease in Australia, with just 187 cases in 2007; then by 2010 the rate of infection had increased to 1,171.
Additionally, "Tyres are combustible. Once ignited, they are difficult to extinguish – producing chemical toxins that affect humans, flora, fauna, waterways and the atmosphere. Because of their unique shape and components, once lit, a tyre fire is almost impossible to extinguish."
In the 1970s, a campaign was organised to dispose of 2 million used tyres into the Atlantic Ocean between two living coral reefs, about a mile off the coast of Fort Lauderdale, Florida.
The intent was to try to provide an aquatic habitat as well as to add to the coral reefs that were already there.
Coastal storms and hurricanes, of which there are numerous off Florida, moved a great quantity of the tyres onto the middle reef, essentially destroying it. In the main area where the tyres were dumped there has been no significant coral growth.
“You get down about 20 feet,” says Army Diver Jason Jakovenko, “and the 34 acre area starts to come into sight… It’s like the moon or something. It’s weird. It doesn’t look like anything you can imagine. It’s just tires for as far as you can see down there.”
The estimated cost for Florida state officials to hire private contractors to remove the tyres was $30 million. Coastal America, a small federal office that is responsible for bringing federal agencies together on large marine projects, brought about the idea to turn this project into a training exercise for the military with the military donating the time and expertise of its divers. This saved the state officials 28 million dollars leaving a need of just 2 million dollars for the transportation and the recycling of the tyres.
The dumping of tyres in the ocean is not unique to Florida or the USA for that matter. Among other countries are Malaysia, Japan, Portugal, France, Israel, Italy, Philippines and Spain.
Queensland University of Technology’s(QUT) Professor Richard Brown says “Globally, 1.5 billion tonnes of tyres are discarded each year. Australia, alone, will generate 55 million disused tyres a year by 2020. “Getting rid of old tyres in an environment-friendly way is a universal nightmare”.
As the world struggles with what to do with end-of-life tyres from cars, trucks and earth moving equipment Australia has been developing and refining a process called destructive distillation to recycle whole tyres. This process also known as pyrolysis occurs when you super-heat tyres in a reactor vessel containing an oxygen-free atmosphere ensuring there is no combustion and therefore no burning.
Pyrolysis reduces the tyres to three main products, Oil, Steel and Carbon Black. A 10kg car tyre yields 4 litres of oil, 1.5kg of steel and 4kg of carbon black. Based on these results using car tyres alone could generate 220 million litres of oil by 2020 just in Australia. The steel remains untouched since it does not get hot enough and is returned to be recycled and used to make new tyres. The high purity carbon is released in powder form, Carbon Black, which steel mills can use as a carbon source, replacing coal or coke in steel manufacturing[3].
The most common use (70%) of carbon black is as a pigment and reinforcing phase in automobile tires. Carbon black also helps conduct heat away from the tread and belt area of the tire, reducing thermal damage and increasing tire life. Carbon black particles are also employed in some radar absorbent materials used in the reduction of the radar cross-section of aircraft and in photocopier and laser printer toner, and other inks and paints. The high tinting strength and stability of carbon black has also provided use in colouring of resins and films. About 20% of world production goes into belts, hoses, and other non-tire rubber goods. The balance is mainly used as a pigment in inks, coatings and plastics. For example, it is added to polypropylene because it absorbs ultraviolet radiation, which otherwise causes the material to degrade. Carbon black has also been used in various applications for electronics. As a good conductor of electricity, carbon black is used as a filler mixed in plastics, elastomer, films, adhesives, and paints. Application of carbon black as an anti-static agent has provided uses as an additive for fuel caps and pipes for automobiles[4].
In addition, the process is emission-free, using recycled oil recovered through the process as the heat source for the production so the only waste generated is heat.
Researcher Farhad Hossain(QUT) said tests conducted on the oil from tyres in 10% and 20% diesel blends. The experiments were performed with constant speed on four different engine loads with no loss of engine performance and a massive reduction in emissions.
QUT’s Professor Richard Brown said they found a 30% reduction in nitrogen oxide which helps to create petrochemical smog and that there was also a reduction by 33% in particle mass. “It is a fuel that is as good as or better than normal diesel… made from old rubber otherwise destined to rot as landfill.”
How do we, as consumers, encourage the use of destructive distillation to recycle end-of-life tyres? Contact your local member of the House of Representatives and let them know that we need to end all practices of disposing of tyres that do not completely recycle the tyre such as with destructive distillation. You can find your local member through the Parliament of Australia website Members Search.
Alternatively you can contact your State Environmental Protection Agency(EPA) and put your concerns in writing either by email or snail mail. Find your state EPA. https://www.google.com.au/search?q=Contacting+the+EPA
[1] Stocks & Fate of End of Life Tyres – https://www.nepc.gov.au/system/files/resources/8f17c03e-1fe7-4c93-8c6d-fb4cdc1b40bd/files/stocks-and-fate-end-life-tyres-2013-14-study.pdf
[2] Why Recycle – https://tyrecycle.com.au/why-recycle
[3] Green steel from old rubber tyres produces no waste or toxic fumes – CRC Association – https://crca.asn.au/green-steel-from-old-rubber-tyres-produces-no-waste-or-toxic-fumes/
[4] Carbon Black – https://en.wikipedia.org/wiki/Carbon_black#Common_uses