Advancing Plastic Waste Management for a Circular Economy: Comparative Insights from Plovdiv (Bulgaria) and Kostanay (Kazakhstan)

Plastic waste management is a critical challenge worldwide, influenced by the socio–economic conditions and policy frameworks of individual countries. This study evaluates the plastic waste management practices in two cities, Kostanay, Kazakhstan, and Plovdiv, Bulgaria, through a comparative analysis of household waste data, recycling systems, and legislative frameworks. The cities are similar in their main features, but the practice of plastic waste management is developed to varying degrees. In the period from 2017 to 2023, the population of Plovdiv decreased by 6.77% and the amount of municipal waste decreased by 3.55%. In Kostanay during 2021–2023, the population of the city increased by about 5%, and the amount of waste generated by more than 25%. Using morphological analysis and municipal records, this research identifies gaps in current practices and explores actionable strategies for enhancing plastic waste recycling. The qualitative analysis of the practice of urban plastic waste management shows that, compared to Plovdiv, the Kazakh city has underused the managerial and technological capabilities in the process of developing the plastic waste management industry and the transition to a circular economy. This study highlights the potential for implementing circular economy principles in both cities, with targeted recommendations to address existing challenges and maximize waste treatment and recycling. In Plovdiv, thermochemical processes for recycling plastic waste into new products are promising, while in Kostanay, mechanical methods for optimizing waste collection and transportation are promising.