The development of the automotive industry worldwide favours the increasing demand for tyres and the formation of a significant number of used tyres, which are considered waste due to their quantity and durability. Moreover, tyres do not degrade in the natural environment for up to 100 years (Gronowicz and Kubiak 2007). Generally the disposal of used tyres and other polyisoprene based products are problems (Juma et al. 2006).
Hence, the tyre has become a waste on a global scale. Waste tyres arise as a result of the operation of vehicles and the dismantling of end-of-life vehicles. The main components of tyres are rubber, fillers, soot, steel, sulphur, zinc oxide, process oil, vulcanisation accelerators, and so on (Rofiqul et al. 2010). The related waste management includes collection, transport, treatment, and disposal including landfilling (Przydatek and Krok 2018). However, landfilling is the most popular method of waste disposal, which wastes the energy and material potential of used tyres and deteriorates the condition of the environment (Segre and Joekes, 2000). Landfills pose a serious threat to the natural environment, fire-fighting, and habitats for insects and rodents (El-Naqa 2005).
To apply the waste hierarchy, European Union (EU) member states have been adopting measures to encourage solutions that minimise environmental impact (Pomberger et al. 2017). Therefore, on a global scale, all waste producers must be included in organised waste collection (Przydatek 2019). Such behaviour is to help protect natural resources and prevent environmental degradation (Gharfalkar at al. 2015). One of the most popular models in Europe in terms of improving used tyre management (and waste) considers optimisation and is based on extended production responsibility (Sienkiewicz et al. 2012; Gaska et al. 2018).
Every year, huge amounts of waste are generated worldwide, especially in the form of used tyres. In China alone, it has been estimated that around 20 million Mg of tyres will be generated in 2020 (Sun et al. 2016). The economy dealing with the alternative side of using waste is increasingly growing. Currently, the ideal solution for getting rid of used tyres is recycling or incineration (Directive 2000/53/EC). In the rubber waste industry, the tyre can also be used as a fuel, as a component of bituminous mass, and in the roofing and paving industries (Silvestravieiete and Sleinotaite-Budriene 2002; Hernandez-Olivares et al. 2002). Another way to manage used tyres is through retreading.
In 2013, the volume of used tyres in the EU reached 13.6 million Mg (Simić and Dabić-Ostojić 2017). The waste tyre management in the EU is regulated by the following legal acts: Council Directive 1999/31/EC, Directive End-of-Life Vehicle 2000/53/EC, and Directive Waste Incineration 2000/76/EC. Based on these acts, parts including tyres are required to be reused, recycled, or recovered, and the disposal of whole and shredded car tyres is prohibited. However, EU member states have the option of choosing a waste tyre management system considering the relevant fees and free market (Sienkiewicz et al 2012).
The product life cycle, or more precisely the life cycle of the tyre, consists of intangible and tangible stages. The first stage includes design and construction. The second stage consists of three phases: manufacturing, use, and disposal of the used tyre. In all phases of the material cycle, the tyre harms the natural environment and human health and exhausts non-renewable resources. In contrast, Clauzade et al. (2010) and Torretta et al. (2015) found that all car tyre recycling/recovery methods provide environmental benefits.
Used tyres are remanufactured, recycled, or co-incinerated in cement plants as an alternative fuel. Used tyre recycling is an extremely difficult process due to the diversity of the raw material from which they are produced (Sienkiewicz et al 2012). Tires should be disposed to reduce their impact on the environment; through incineration which is the fastest and easiest discarding procedure (Machin et a. 2017).
The main reason for the need to neutralise waste is the development of civilisation and the improvement of the standard of living of society. As a result, waste and alternative technical solutions are increasingly generated.
According to the hierarchy of waste management, the prevention of waste is required. When this is impossible, it is necessary to act to ensure recovery and recycling and to prevent landfilling (COM 2005). Landfilling of used tyres is prohibited, except for bicycle tyres and tyres with an outer diameter greater than 1,400 mm (Act on waste 2012). A valuable element in the management of used tyres is energy recovery with their participation (Huang et al. 2012).
Unfortunately, many tyres are sometimes damaged or destroyed, so a possibility of recycling them in the recycling process must be found, giving them a new shape or function. Too much of this type of waste causes excessive accumulation, leaving recovery less likely. Rubber, steel, and textiles that are suitable for reuse or energy generation are eligible for recovery. Recycling with the use of used tyres, demonstrated in the course of recovery, aligns with environmental protection. The study aims to assess the efficiency of selected issues waste tyre management in Poland from 2008 to 2018 while considering their rational recovery.
Description of examined country
Poland is a country located in Central Europe. The country ranks 69th in terms of its area (312,696 km2) and 36th in terms of world population and ninth in European population. In administrative terms, Poland is divided into three levels: voivodeship, district, and commune. The largest area of 35.579 km2 is occupied by the Mazovian Voivodeship in the central part with the largest number of inhabitants, while the smallest area is 9.412 km2 by the Opolskie Voivodeship, in the south - western part of the country (Przydatek 2020). The lowest average population density is in the voivodships Podlaskie and Warmian-Masurian.
Used tyre management in the country
In Poland, the used tyre collection system is implemented primarily by vehicle service stations and end-of-life vehicle dismantling stations (NWMP 2016). A significant supplement to the collection of used tyres is selective waste collection points and waste management plants. The largest number of collection points for used tyres is located in the Greater Poland Voivodeship, despite the registration of the largest number of vehicles in the Mazovian Voivodeship (CRVD 2018).
Many tyre collection points exist in the country due to the ban on landfilling (waste code 16 01 03 – used tyres) (Regulation 2014). Sixty plants deal with the management of used tyres; few of them deal with comprehensive disposal or recycling of materials. In the Opolskie Voivodeship, an installation enables the co-combustion of used tyres. According to Wasilewski and Stelmach (2009), such a process is favoured by the significant calorific value of tyres with a value of 31.4 MJ kg-1. One of the factors aimed at reducing the amount of waste generated both in Poland and the EU countries is the use of the waste hierarchy, including recycling, which reduces the effect of waste on the environment, the consumption of natural resources, and the costs (Eriksson et al. 2005).