Effectiveness of Selected Issues of Used Tyre Management in Poland

The study aimed to assess used tyre management eciency in Poland from 2008 to 2018, considering their recovery based on EU and national regulations. Within 11 years, over 5 million Mg of used tyres were introduced to the domestic market, exceeding 50 million registered vehicles. A signicant process in tyre waste management was the recovery of 47% of tyres, which was almost fully correlated with the total amount of tyres. Only the growth trend of the manufactured tyres was considered signicant, and the rarely used indicator of the accumulation of used tyres per area showed an uneven accumulation of worn tyres with the highest amount of 48.06 Mg km -2 in a region with a small area but signicant volume of tyres. Therefore, management of used tyres requires taking actions that optimise increasing waste collection and rational recovery in the context of the further minimisation of environmental pressure and increasing the eciency of their use, taking into account the advanced technology.


Introduction
The development of the automotive industry worldwide favours the increasing demand for tyres and the formation of a signi cant 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, llers, soot, steel, sulphur, zinc oxide, process oil, vulcanisation accelerators, and so on (Ro qul et al. 2010). The related waste management includes collection, transport, treatment, and disposal including land lling (Przydatek and Krok 2018). However, land lling 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). Land lls pose a serious threat to the natural environment, re-ghting, 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 roo ng and paving industries ( 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 rst 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 bene ts.
Used tyres are remanufactured, recycled, or co-incinerated in cement plants as an alternative fuel. Used tyre recycling is an extremely di cult process due to the diversity of the raw material from which they are 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 land lling (COM 2005). Land lling 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 e ciency 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 km 2 ) 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

Methods And Materials
The acquisition of data was based on a questionnaire addressed to 16 individual Provincial Marshal O ces in Poland and owner observations. Based on the data from annual for the years 2008 to 2018 that include the total sum and sums of the quantities of tyres whose were generated, collected, recovered, an analysis was conducted that includes the determination of the mass accumulation indicator of tyres by According to Miliute-Plepiene and Plepys (2015), the number of studies considering waste accumulation indicators is increasing, which may result from the need to identify factors causing an increase in the mass of generated waste. In addition, based on Statistics Poland (2008-2018), the number of registered vehicles in Poland was determined. This number included motor vehicles, buses, lorries, special cars, tractor units, agricultural tractors, motorcycles, and mopeds. The obtained data constituted the basis for the assessment of the e ciency of used tyre management.
A statistical analysis was also performed that included the maximum, minimum, and average. To determine the correlation relationship meeting the condition of the normal distribution for the data covering the total number of tyres, including those generated, collected, and recovered, the Pearson linear correlation coe cient method was used. When the condition of normal distribution was not met, Spearman's rank method was applied. The Spearman correlation coe cient R is a non-parametric equivalent of Pearson's coe cient. As with parametric correlation, the Spearman correlation coe cient R measures the strength of the correlation between variables. Non-parametric tests were used due to the lack of normality of the distribution of most of the analysed indicators following the results of the Shapiro-Wilk test (p <0.05) (Przydatek and Kanownik 2019).
A ow chart (i.e. a line chart for cases) and a cluster analysis were used to explain the detection of the structure of the data, considering the hierarchical agglomeration method, allowing the determination of the tree hierarchy of elements of the analysed set. The non-parametric Mann-Kendall statistical test was chosen to test a series of numbers in terms of identifying an upward or downward trend that is not necessarily linear. Statistica 13 (StatSoft Poland, StatSoft, Inc., USA) was used for statistical analysis. The total amount of tyres during the 11 analysed years ranged from 708.24 to 135,570 Mg with an average of 32,741 Mg (Tab. 2). The highest amount of collected tyres occurred in 2017, while vehicles in the following 2018 (Fig. 1).
The accumulation indicator of collected tyres per country area in the analysed years ranged between 1.94 and 2.12 Mg·km -2 . In turn, the number of vehicles registered in the analysed period was from 43,389,232 to 62,570,032 which was an increase of as much as 19,180,800. The extreme values for both the number of tyres and the rate of accumulation of worn tyres were recorded in 2008 and 2017 (Fig. 1). Figures 2 with the dominance of waste recovery at the level of 47% (Fig. 3). However, the maximum values differ signi cantly in this respect. The highest value of 80,197 Mg occured in the case of collected tyres.

The variability of the indicated indicators is presented in
The average values of collected and recovered tyres were respectively 14,295 and 16,060 Mg. In case of the generated tyres average amount was the lowest amounted to 3,950 Mg (Tab. 2), similarly share of 11% (Fig. 3). The highest correlation value of 0.90 occurred between the total tyres amount and recovered tyres. The correlation value of 0.73 between the total number of tyres and collected tyres was high. The recovered tyres correlate with the collected tyres (0.43), which is a moderate correlation. The remaining relationships between the collected tyres and number of generated tyres, the total quantity of collected and generated tyres, and the recovered tyres did not exceed 0.4 (Tab. 3).
However, the trend study con rmed only a statistically signi cant increase in the generated tyres and a decrease in the collected tyres (Tab. 4).

Discussion
The total amount of used tyres over 11 years in the country exceeded 5 million Mg with an average of 32,741 Mg, which con rms that this waste poses a serious problem in the area of environmental protection. According to Karaağaç et al. (2017), in Turkey, the annual amount of waste tyres is estimated at a higher level of 250,000 Mg. Similarly in Greece amount of collected waste tires exceeded 50,000 Mg One of the important aspects of waste management is the prevention of waste. However, in the case of worn tyres, the prevention of their formation is limited for the sake of road safety in the scope of the required minimum tread height of a tyre. This indicates that the increase in the amount of used tyres depends on the number of vehicles in use. The average number of vehicles in the analysed period was over 1.5 times higher than the number of tyres collected. As the number of vehicles increases, so does the amount of tyres and their waste (Yadav and Tiwari 2017). Despite the successive increase in the number of vehicles, the largest amount of used tyres occurred in 2017. This result was observed in the centralwestern part of Poland, where the largest number of tyre collection points is located. De Figueiredo and Mayerle (2008) noted that the level of recycling of used tyres depends on the optimisation of the number and location of collection points. Despite the favourable results, however, the reuse of rubber as part of recycling in EU countries becomes problematic due to the declining demand for granules due to the economic crisis (Torretta et al. 2015). In contrast, Karaağaç et al. (2017) indicated that the demand for polymeric materials has been increasing in recent years in Turkey.
According to Skarbek and Michalski (2012), the solution for the rational management of used tyres is recovery and recycling. As part of the recycling process, used tyres are used in the production of bituminous mass, which allows lower costs concerning raw materials (Hsisheng et al. 1995). Ahn and Chen (2014) demonstrated that most tyres are not properly managed by land lling, among others on 'wild' land lls. Moreover, Isse and Salem (2013) classi ed combustion as one of the most popular methods of tyre management, the side effect of which is the emission of pollutants into the atmosphere. In Italy, about two-thirds of energy is produced on this basis (Torretta et a. 2015). The recovery of this energy is most often carried out by direct burning of tires (fragmented or whole) or in the pyrolysis process (Fig. 4), which is one of the effective processes of thermal conversion of waste with the calori c value of the pyrolytic liquid within the range of 41-44 MJ kg − 1 (Williams 2013). One of the researcher (Godlewska, 2017) showed that most often waste tires recovery means energy recovery.
In turn the recovery of used tyres in Poland was signi cant and amounted to 47%. This result indicates that the risk to the environment is minimised following the 4R principle (Mmereki et al. 2016

Conclusions
The analysis of the test results for the total amount of used tyres, including those generated, collected, and recovered in Poland, allowed for the formulation of the following conclusions: Under EU requirements and the hierarchy of waste management in the country, tyres were reused, recovered, and recycled.
The signi cant average amount of used tyres, 32,741 Mg, con rms that this waste poses a potential problem in the area of environmental protection.
The average number of vehicles in relation to the amount of worn tyres, over 1.5 times higher, occurred with a noticeable growth trend of generated tyres.
The tyre accumulation index per country area was 2.12 Mg km -2 at achieved by 48.06 Mg km -2 in one of the smallest Voivodeship in Poland.
The largest amount of used tyres occurred in 2017, despite the successive increase in the number of vehicles in the central -western part of the country with the largest number of tyre collection points.
Recovery of used tyres at the level of 47% exhibited a moderate correlation with the collection, whereas the correlation with the total amount of tyres was almost full.
The desirable and at the same time effective direction of the utilization of used tires in domestic conditions should be their e cient thermal conversion with energy recovery.  Table 2 Average amount of generated, collected and recovered waste tires in Poland  The data of amount Linear variation in the value Share of individual processes