Waste management in the context of digitalization and the circular economy development

The study focuses on the analysis of existing approaches to waste management in different countries, taking account of digitalization and the circular economy development. The authors’ main objective was to define strategic guidelines for ensuring the formation of a waste management system by means of determining the level of achieving the waste management goals by various countries and studying their best practices in this field. The authors applied a clustering method to group the chosen countries based on the level of their indicators in waste management, digitalization, economic growth and achieving sustainable goals. In addition, cluster analysis was used while conducting the research. The study resulted in separating four clusters of the countries depending on their level of the selected indicators in 2022. The results of the research suggest that infrastructure and support of the state are essential factors in successful waste management. The authors offered some recommendations to facilitate the development of smart waste management by the states based on circularization, digitalization, interaction and regulatory support.


1.Introduction
The concept of a circular economy (a closed loop economy) is based on the fact that a circular economy provides value creation mechanisms that do not recognize the use of limited resources [1].Every year, 2.01 billion tonnes of municipal solid waste is produced globally, and, at least 33 percent of that amount is not managed in a way that protects the environment.Statistically, a person generates on average 0.74 kilograms of waste a day, but this figure varies greatly, from 0.11 to 4.54 kilograms.Although highly developed countries constitute only 16 percent of the world's population, they produce around 34 percent of the world's waste, or 683 million tonnes [2].In the future, it is expected that the amount of global waste will go up to 3.40 billion tonnes by 2050, which means that it will be twice as much as the population growth over the same period.In general, a positive correlation between levels of income and waste generation is observed.It is predicted that by 2050 high-income countries will face a 19% rise in daily per capita waste generation as opposed to low-and middle-income countries, where this index may increase by almost 40% or more [2].Therefore, the introduction of the circular economy concept into business practice and ensuring an effective policy on the circular economy development to improve the waste management system at the national level open up new horizons for society and the economy and it is currently one of the most topical problems for scientists and practitioners.The important 1269 (2023) 012003 IOP Publishing doi:10.1088/1755-1315/1269/1/012003 2 elements of the circular economy are its R-principles, due to the observance of which a significant reduction of waste and carbon emissions is achieved.These include Recycle, Rethink, Reduce, Reuse, Repair, Refurbish, and Recover [3; 4].In practice, the circular economy actually boils down to minimizing waste.Therefore, Smart waste management is an integral and key component of the circular economy.By its very nature, Smart waste management ensures the formation of a closed loop, promoting the transition from a linear economy to reusing and recycling as much waste as possible so that it can re-enter the economy [4].Waste management is at the heart of SDG 12, which is one of the 17 Global Sustainable Development Goals approved by the United Nations in 2015 and such goals define the strategic direction for ensuring sustainable development in the world.
In turn, studies have shown [5; 6; 7; 8] that digitalization processes in the economy contribute to the development of waste management models in the context of the circular economy, in particular, maximizing resources, reducing waste, reducing energy intensity and the level of harmful emissions into the atmosphere.This proves that there is a need to take into account these factors for determining successful practices in the field of waste management based on the study of the experience of individual countries and justifies the purpose of this study.To achieve this purpose, it was important to establish the criteria that identify the factors in the circular economy development, sustainable development and digitalization.
Clustering and defining the typology of countries based on these characteristics will allow for a targeted study of an effective economic policy and measures to develop the circular economy.Consequently, the above determines the relevance of this study.

2.Material and methods
The stages of conducting the research are as follows: 1) analysis of the theoretical foundations of waste management based on the principles of the circular economy; 2) determination of indicators that characterize the level of development of waste management based on the principles of the circular economy, taking into account the conditions of digitalization and countries for cluster analysis; 3) determination of clusters of countries based on the selected characteristics; 4) interpretation of the analysis results and determination of best global practices to ensure effective waste management.
The countries with a high level of sustainable development, leading economies and some neighboring countries of Ukraine were selected for cluster analysis.It was necessary to choose those indicators that determine the chosen direction of research and characterize the level of development of waste management based on the principles of the circular economy, taking into account the conditions of digitalization.They are: − Waste Management (WMG) is an indicator that belongs to the issue category of the Environment Performance Index and indicates the level of threat of solid waste to human health, and includes such indicators as Controlled solid waste, Recycling and Ocean Plastics; − GDP per capita, purchasing power parity (constant 2017 international $) -gross domestic product converted to international dollars using purchasing power parity rates, which characterizes the performance of the economy; − SDG 12 is an indicator of the achievement of Sustainable Development Goal 12, which is one of the 17 Sustainable Development Goals established by the United Nations in 2015, and is defined as ensuring sustainable consumption and production patterns; − ICTS is a sub-index of the Global Innovation Index, which indicates the development of digitalization as a supporting infrastructure and consists of such indicators as ICT access, ICT use, Government's online service, E-participation.In order for the data to be of the same dimension, it is necessary to normalize them.The min-max normalization method was chosen according to the formula (1): − where the number of the indicator,  -the country's number,   the value of the i-th indicator for the j-th country.The research is based on cluster analysis.Cluster analysis [9] is a statistical division of the total set of data into subsets (clusters) that have common features in the subset.Clustering refers to "unsupervised" machine learning algorithms that group elements into clusters in such a way that elements of various groups are significantly different, as opposed to elements in a group united by common characteristics.Some algorithms make it possible to track outliers -elements that do not belong to any cluster, because they have unique features, or are very different from the formed clusters.
A K-means method was used for cluster analysis [9].It is an iterative method that forms clusters in which the sum of the Euclidean distances from the center to the elements of the clusters is minimal.
The Elbow method is used to determine the optimal number of clusters.It is necessary to choose the value of k at the "elbow",i.e., at the point after which the distortion/inertia starts to decrease linearly.The R programming language was used to make calculations. .

3.Theory and calculation
The circularization processes of the economy and methods of assessing the level of its development have become the object of a lot of contemporary theoretical and methodological research as well as business practices.Walter R Stahel [2] argues that when the life cycle of products ends, a circular economy changes them into resources, and, in this way, it is possible to minimise waste and close the loop in production.In this system, a product and each part of it is considered a reusable resource that can create value added.Hence, resources never stop to circulate in a circular economy.Thus, the scientists [11] rightly point out that the purpose of this concept is to solve a number of environmental problems such as waste generation and resource scarcity with the preservation and even growth of economic and social benefits and maximizing value at each point in a product's life.Therefore, it can be argued that the concept of a circular economy is based on environmental, resourceful and economic pillars.
The demand to implement the circular economy's principles and waste management models is growing with the growth of world production.Figure 1 shows the level of greenhouse gas emissions by country, and it can be seen that industrial and agricultural countries, countries with a high level of fossil fuel consumption have a high level of greenhouse gas emissions.The highest level of greenhouse gas emissions is observed in the USA and China, as well as in India, Brazil, Iran, Indonesia and russia.For 10 years from 2010 to 2020, the reduction of World CO2 emissions (kg per 2017 PPP $ of GDP) amounted to 6% (Figure 2), and the further acceleration of this indicator is determined by the goals of sustainable development until 2050, which is confirmed by the strategies of leading developed countries.In addition, more and more scholars notice and research the relationship between implementing the circular economy concept and ensuring sustainable development through the achievement of the Sustainable Development Goals.In particular, Linser S. and Lier M. [14] summarize that the principles of sustainable economic development (renewability, balance, involvement) correspond with the goals of the circular economy.Kirchherr J et al. [15] explain the popularity of the circular economy concept, viewing it as "operationalization for businesses to implement the much-discussed concept of sustainable development".However, one cannot disagree with Awan U. and Sroufe R. [16], that both the circular economy and sustainable economy require a deep understanding of needed infrastructure for their implementation.First of all, it is about regulatory support for the implementation of circular initiatives at the level of national governments.
Furthermore, it is clear that innovations and the latest digital technologies should be the basis of building new business models using the principles of circularization [17].One more crucial factor in the circular economy implementation is the effective interaction of all participants in circularization processes, from end consumers to the state.All these factors in the circular economy formation require a more detailed study, which is the basis of this research.
Many modern scientists have devoted their research to determining indicators and assessing the state of waste management and the circular economy development in general.For instance, according to the research [18] into Waste Management Issue Category in the context of state administration quality, Waste Management Issue Category includes the indicator called Controlled Solid Waste.This metric shows the share of waste produced by households and commercial businesses in a country that is collected and processed in such a way that environmental risks are controlled.The indicator regards waste as "controlled" when it undergoes such processes as recycling, composting, anaerobic digestion, incineration, or it is disposed of in a special sanitary landfill, and the range of this category is from 0 to 100.
The input data for these indicators are presented in Table 1.Thus, for the given data, it can be concluded that the optimal number of clusters is 4 (Figure 3).Based on the results of the analysis, 4 clusters were obtained (Figure 4).Cluster 1 includes such countries as Austria, Canada, Denmark, Estonia, France, Slovenia, Sweden, Norway, the Netherlands, United Kingdom, Japan.Poland, Spain, Bulgaria, Portugal, Italy, Lithuania, Slovakia, Germany, the Czech Republic, Latvia and Belgium belong to Cluster 2. Cluster 3 comprises Сhina, Turkey, Belarus, Ukraine, Romania, Hungary, Moldova and Georgia.Ireland is singled out as a separate Сluster 4.
The average score of the Waste Management indicator in the Cluster 1 is 66.3, and among the formed clusters, Cluster 1 ranks second according to this indicator after Cluster 4 (67.9).The average value of GDP per capita also ranks second after Cluster At the same time, in terms of sustainable development, it should be noted that according to the Sustainable Development Report definition methodology, the indicator is an identifier of progress, so, for example, in some developed countries, progress is slower than in developing countries.A high level of achieving the goals in the past by developed countries is contrasted with significant progress made by countries with a lower level of income, however, they are just beginning to actively develop the directions of sustainable development.
Therefore, based on the general characteristics of the formed clusters, the most efficient countries in the field of waste management are those in Cluster 1 and Cluster 4. At the same time, high positions in the development of the circular economy are accompanied by high profitability of the countries and a high level of digitalization of the economy.Cluster 2 is at the transformation stage to ensure the principles of the circular economy, and the countries in Cluster 3 have still unrealized potential in the circular economy development.However, in each cluster, there are countries-leaders in terms of the level of waste management in the cluster, and one can trace the connection between the level of digitalization and the circular economy development in those countries.Among the 35 countries under study, Ireland ranks 9th in terms of waste management, 1st in terms of GDP per capita, PPP; it has a low level of SDG 12 (a decrease in the indicator) and a high level of ICTS (91.5).A Waste Action Plan for a Circular Economy: Ireland's National Waste Policy 2020-2025 was published by the Government of Ireland in 2020.Within the framework of this plan, there are measures in the areas of household and business, plastic, packaging and single use plastic (sup), food waste, extended producer responsibility, construction and demolition waste, textiles, government leadership on the circular economy enforcement, treatment.
Austria has the highest level of waste management.The Austrian Waste Management Act (Abfallwirtschaftsgesetz) lays down fundamental principles of Austria's waste management.They comprise the protection of human beings and the environment, sustainability and the conservation of natural resources.The Landfill Ordinance (Deponieverordnung) stipulates that residual waste must be subject to thermal or mechanical biological treatment in order for the waste to become non-hazardous for peoples' health and the environment and only then it can be dumped into landfill.Such measures help to avoid chemical reactions in landfill sites, thus preventing possible air, soil or water contamination.
Finland, which is part of Cluster 1, is the first country to develop a national road map for the transition to the circular economy concept.Germany, despite belonging to Cluster 2, is considered a leader among other countries in the field of waste processing: the share of waste returned to useful circulation is 66%.
The relevant decisions in the field of waste management are enshrined in the Circular Economy Act ("Kreislaufwirtschaftsgesetz"/KrWG), which is currently the main one in the German waste management system.At the center of the waste management system is the waste hierarchy defined by the European Waste Framework Directive.In addition, German waste management system is based on advanced recycling and thermal treatment of waste, completely avoiding landfilling of solid waste, which has been forbidden in the country since 2005.In 1991, the Packaging Resolution ("Verpackungsverordnung" or VerpackG) was adopted, which implemented the "polluter pays" principle towards producers.In particular, this principle requires retailers to accept free returns of used empty packaging at or near the point of sale from the end user.In response to these demands, the dual system DSD (Duales System Deutschland or German Green Dot) emerged in Germany, which is a jointstock company whose members are packaging and product manufacturers, retail companies and waste disposal companies.Thus, in the German waste management system, not only the state takes an active part, but also private business, which provides and pays for the disposal of "its" (paper, dishes, electronics, cars, etc.) waste.
The Czech Republic has a high level of a circular economy (Cluster 2).The Waste Prevention Programme of the Czech Republic (WPP CR) is composed of 1 main objective and 12 sub-objectives.The main objective of preventing waste is to promote ways of waste prevention, minimize the quantity of waste and the consumption of primary resources.In Sweden (Cluster 1), which has embraced a "Zero Waste" vision, more than 99% of waste is recycled.Switzerland is a leader in glass recycling, which was supported by the Program for the collection and recycling of used glass adopted back in 1972.The experience of Poland (Cluster 2) is interesting, because there is a concept of reverse logistics within waste management, i.e. the consumer has to deliver waste to the producer for further processing, reuse, and repair.
Ukraine is included in Cluster 3, and it ranks last among the studied countries in terms of waste management and GDP per capita.However, at the same time, Ukraine has a relatively high SDG 12 indicator, and a relatively high level of digitalization in Cluster 3, which indicates considerable potential.The war in Ukraine and the continuous military aggression of the russian federation testify to the fact that the energy utilization of waste, the issue of the disposal of military waste and the directions of ensuring sustainable development at various stages of socio-economic development are of particular relevance today.
Before the war Ukraine has made some initiatives in supporting world processes in circular economy.Thus in 2021 as a result of a dialogue with the EU, Ukraine set the National 2030 Economic Strategy with a goalt for climate neutrality by 2060.Ukraine also adopted the National Environmental Security and Climate Adaptation Strategy and joined the Global Methane Pledge and Powering Past Coal Alliance at COP26 in Glasgow.
But even in the war conditions, Ukraine adopted a number of legislative acts in the field of a circular economy and waste management.For instance, in July 2023, the law "On waste management" came into force.This is a framework document, within which the reform of the country's waste management will be built.It provides for the creation of a new permit system on a new information platform, the regulation of waste management powers, multi-level planning from the National Plan to the plan of individual enterprises, the infrastructure development, the implementation of European waste management practices (the development of a waste hierarchy, placing greater responsibility for pollution on producers, etc.).
In Georgia among other legislative initiatives in circular economy formation it is worth to point out The Waste Management Code, which was adopted in 2014.It is based on the experience of EU countries and the best international practices.It supports such processes as waste prevention, reusing, recycling and composting.
The European Circular Economy package (the European Commission, 2015) and The Waste Framework Directive, which is the EU's legal framework for treating and managing waste in the EU [4], are in force in EU countries.According to them, such stages of waste management are defined: 1) preventing waste, 2) preparing waste for being re-used, 3) recycling waste (material recovery), 4) other recovery (e.g.energy recovery), 5) the disposal of waste.According to the EPI report, leaders in this area have adopted waste management hierarchies that prioritize recycling, composting, and waste-toenergy incineration for value recovery from waste material [5,19], which, in our opinion, ensured their leadership in waste management indicators.
Taking into account the above, the priorities for the circular economy development are such measures as: -state support for the development of legislative acts in the field of a circular economy and waste management; -approval of the waste hierarchy; -formation of an effective waste management infrastructure; -coordination of the interaction among all participants of the waste management system at each stage; -promoting the spread of new circular business models based on the concept of Industry 4.0,5.0;-encouraging business to implement circular innovation.

4.Conclusions
The conducted research has made it possible to determine clusters of countries taking into account a comprehensive approach to evaluating the growth of the circular economy using 4 criteria that characterise waste management, economic growth, improvements in the circular economy development in relation to SDG12 indicators, and the level of digitalization.This has helped to determine 4 clusters, rank them and identify individual leading countries, whose experience in the formulation of economic policy should be taken into consideration for facilitating the growth of a circular economy.It has been recommended to use the initiatives of Austria, Ireland, Finland, Germany, the Czech Republic, Finland, and Poland as a basis in the formation of the concept of waste management in developing countries.Priority directions in the waste management system have been defined.

Figure 3 .
Figure 3.The criterion for choosing the number of clusters.
4 and is 50,823.71US dollars.Cluster 2 is in third place in terms of GDP per capita with an average of 39,715.54US dollars.The average ICTS indicator in Cluster 1 is the highest and amounts to 90.1.According to the same indicator, Ireland is in second place with a score of 81.8.Regarding progress in achieving SDG 12, Cluster 1 also takes the leading position with an average value of the indicator of 90.2, but Cluster 3 takes second place with an average value of the indicator of 84.5, Cluster 4 is in third place with Ireland's indicator of 81.8, and the last place belongs to Cluster 2, which has an average value of the indicator 70.3.

Figure 4 .
Figure 4. Clusters of countries according to the selected indicators of waste management based on the principles of the circular economy in the conditions of digitalization.

Table 1 .
Input data for cluster analysis for 2022.