The problem is not just that tyre dumps are unsightly.There are also tangible health issues, for example tyre stockpiles collect rainwater and provide favourable breeding grounds for mosquitos and vermon. In 1985 the Asian tiger mosquito was found to have spread across the south of Texas, after having arrived via end-of-life tyres from Japan. The mosquito is thought responsible for an outbreak of West Nile virus in Texas in 2012 which killed 89 people. Tyre dumps also pose a high risk fire hazard. In 2012 a tyre fire broke out in Kuwait at a dump containing more than 5 million tyres. The fire was so extensive that the smoke plume was visible from space. This type of fire creates air pollution in the form of carbon monoxide and benzene, and can also contaminate nearby water sources with lead and arsenic compounds. Furthermore the heat created by tyre dump fires can result in oil leaching into the ground … did you know that one car tyre holds around 9 litres of oil?
In Thailand where we manufacture our goods, there are around 600,000 tonnes of tyre waste produced each year, and this amount is on the increase as car ownership within the kingdom continues to rise. Thailand is also one of the world’s largest producers of natural rubber. Of the 3.35 million tonnes produced in 2011, 60% was processed into tyres and tubes. What happens to these tyres when they are no longer usable? Well, in 2013 some 63% of waste tyres in Thailand were disposed of through dumping, open burning and landfill. The landfill, while reducing some of the health and environmental issues related to open ground dumping, is expensive to do properly, and utilises a lot of space due to the resistance of tyres to compaction and decomposition. Retreading is one of the most resource-efficient processes for recycling waste tyres and makes use of the tyre for its original purpose. However, it is limited to repairable waste tyres as opposed to scrap tyres and in reality, only 1 % of waste tyres in Thailand are retreaded and put back into use. Repurposing the tyre’s constituents is another option via grinding processes that result in a tyre-derived aggregate, which can then be used as mulch for agriculture and playgrounds, as artificial turf filler, or an additive in rubberized asphalt. A well-established rubber reclamation industry operates in Thailand with 4% of waste tyres undergoing a process known as devulcanization. This results in a fine rubber powder which can then be transformed into rubber tubing, sheets, and mats. Tyres can also be used as an alternative to coal for high temperature incineration, but there exist the same emission concerns as with the burning of fossil fuels. Pyrolysis is another technology that shows some promise. Heat and pressure are applied to transform tyres into carbon, steel, and oil. The process has some environmental side effects, however, as it is energy intensive and produces hydrocarbon gases. Shortcuts in the pyrolysis process can exacerbate environmental damage, pointing to the need for strong government regulation of this industry.
Within Australia, there are some 51 million tyres discarded per annum, of which only 5% are actually recycled in Australia. The rest are disposed of as landfill, stockpiled, illegally dumped or exported overseas. The Tyre Product Stewardship Scheme was established by the federal government in 2014 in an attempt to encourage the sustainable use of Australia’s end-of-life tyres www.tyrestewardship.org.au . It is hoped that the scheme will lead to the development of a new and innovative tyre recycling industry, which will in turn create employment while reducing the environmental risks of illegal dumping and exporting. Companies such as Green Distillation Technologies (http://gdtc6.com/) are emerging with new technologies and processes that produce minimal emissions while reducing tyres to their constituent elements i.e. carbon, oil, and steel.
Unfortunately, the global tyre dump is growing by the day. The solution to the problem lies in how we view tyre waste. Is it a form of garbage that needs to be disposed of, or is it a valuable resource waiting to be exploited and value added? With the development of innovative technologies from the private sector along with government policy and regulatory alignment, an opportunity exists to build the momentum and capacity needed to tap into this massive and valuable resource.
Connor, K, Cortesa, S, Issagaliyeva, S & Meunier, A 2013, ‘Developing a Sustainable Waste Tire Management Strategy for Thailand’, Research Paper sponsored by the National Science and Technology Development Agency.
Green Distillation Technologies website http://gdtc6.com/
Houston Public Media website http://www.houstonpublicmedia.org/news/texas-looks-at-illegal-tire-dumping-as-health-threat/
Jacob, P, Kashyap, P, Suparat, T & Visvanathan, C 2014, ‘Dealing with emerging waste streams: Used tyre assessment in Thailand using material flow analysis’, Waste Management & Research, vol. 32, no. 9, pp 1-9.
Tyre Product Stewardship Scheme website http://www.tyrestewardship.org.au/
US Environmental Protection Agency website https://www.epa.gov/