Ever wondered about the tyres that are no longer roadworthy after they are used? They are stockpiled, dumped in landfills, or just thrown away on roadsides. This linear product use approach results in a massive waste.
Tyres, whether it is electric, solar powered, gasoline, or hydrogen fuelled vehicle, are indispensable components for the transportation industry. Scrap tyres have potential to harm local environments and negatively affect human health. The most common problems associated with waste tyres are open-air fires and the creation of breeding ground for rodents and mosquitoes. It’s bad but it’s a fact. According to The Freedonia Group Report it is estimated that the world demand for tyres is forecast to rise 4.7 percent per year through 2015 to 3.3 billion units. Approximately same amount of tyres are disposed of every year and almost 20% of them are illegally dumped in landfills, or just thrown away on roadsides.
Is this the end of the story? No, these approaches can ultimately lead towards right environmental choices and would make good financial sense.
The alternative to the growing waste concerns is to develop a circular economy, which goes much further than recycling, and there is a strong business case for development. Building recycling industries to recover, recycle and process the waste tyres – with the focus on the reduce and reuse principles, unemployed people can find gainful employment, SMEs can be developed and, the environmental disaster that waste tyres represent can be economically and effectively addressed. Analysis by McKinsey estimates that shifting in this direction of circular economy model could add $1-trillion to the global economy by 2025 and create 100 000 new jobs within the next five years. It’s worth it!
A normal used passenger car tyre weighs 7.2 kg; it contains at least 238 MJ of thermal energy, which can be useful in some dedicated facilities. In thermoelectric plants, tyres are fed into the hearth without any pre-treatment or slicing. This process is an economically viable alternative for used tyres that cannot be effectively re-treaded, generating a large amount of by-products. Each ton of input (as tyres) generates 287 kg of solid residue made of zinc oxide, ferrous slag and gypsum, each with a well-defined market. The use of old tyres as fuel has the advantage that it does not generate any waste beyond what is usually generated by a standard cement production process. Sliced tyres can be fed into the kiln with the other raw materials. The energy in the rubber provides the heat while the combustion residues are incorporated in the cement without compromising the product’s quality. The ferrous material from the steel wire partially substitutes the large quantities of iron ore used in cement production. Several fuels are used in a cement plants including coal, natural gas and oil. The rubber may provide roughly 20% of the heat required in the kiln, generally at a lower cost than the other fuels. The high temperature of combustion, around 1400°C, under appropriate supply of oxygen, ensures complete burnout of the organic material.
Rubberized asphalt is an alternative to traditional paving material that combines the strength and versatility of asphalt and the longevity and flexibility of recycled rubber. Derived from scrap tyres, the material is said to be longer lasting, safer, less costly and friendlier to the environment than traditional paving materials.
Scrap tyres can be processed into ground rubber to modify asphalt thereby creating rubberized asphalt and rubber asphalt concrete. Asphalt companies buy large quantities of shredded rubber crumbs to mix with their hot melt asphalt to make pavements cheaper. Other road construction companies purchase large quantities of medium sized shredder tyres to use in road beds for minimizing vibrations and for highway sound barriers. Rubberized asphalt is not just sustainable, but actually better than the traditional alternative, better in every way.
Old tyres can be used in barriers such as collision reduction, erosion control, rainwater runoff, wave action that protects piers and marshes. With a blend of art and engineering, the civil engineering applications of waste tyres are emerging.
We can use old tyres in child’s play areas. They’re great for setting up an obstacle course or making a sandbox or a tyre swing. Tyre mulch is also sold as padding for children’s playground. We can make soles for shoes or even entire pairs of flip-flops. We can make livestock feeders or pet house out of old tyres. Used tyres can be transformed into furniture with a little pie of skill and imagination. Since tyres are black and they retain the heat from the sun easily, you can use them in your garden for growing your plants earlier. Basically, you can grow plants and veggies in tyres earlier than in the ground. This trick works great with those species that require more warmth. You can make an outdoor storage bin using old tyres secured together with some plywood and painted in your favourite colour. Old tyres can be transformed into a cool coffee table or other cool pieces of furniture. Just dive, there’s a world of thing you can do. Re- think!
It has been years since we dumped the opportunities for business through valuation of the waste. But, an era is evolving to turn the wastes in every bin into something really spectacular and create value. It is a new shift in the resource management approach, a transition to the unexplored territory and it provides battle against the traditional inertia of waste management. This is the way towards sustainable economies and eco-innovation, and can drive development across the board. This benefits all of us.
About the authors:
Bipin Karki is a graduate student of Renewable and Clean Energy at University of Dayton, and Former TGG Mentee at WWF Nepal (carried out project to reuse tyres). He can be reached at [email protected]
Bishnu Parajuli is an undergraduate student of Industrial Engineering at Institute of Engineering, Thapathali Campus and the President of Society of Industrial Engineering Students – Nepal. He can be reached [email protected]