Seasonality of Municipal Waste Generation: Evidence from a County-Level Case Study in Romania

Municipal waste management is a major challenge for sustainable development, as it is strongly influenced by socioeconomic dynamics, seasonality, and the local institutional framework. In this context, this study aims to analyze the seasonality and structure of municipal waste streams at the county level, using monthly operational data provided by the Integrated Waste Management System in Bacău County, Romania. The analysis is based on descriptive statistical methods, seasonal indicators, nonparametric statistical tests, and exploratory multivariate techniques. Seasonal variability was assessed by calculating monthly and seasonal indices, and differences between seasons were tested using the Kruskal–Wallis test. Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) were used to explore the relationships between waste generation patterns and selected temporal, socioeconomic, calendar, and climatic factors. The results of the analyses reveal a pronounced seasonal pattern, characterized by minimum waste generation during the cold season and maximum generation during the summer months. Residual waste dominates the overall composition throughout the year, while the share of recyclable waste remains low, and the fractional composition remains relatively stable across seasons. Statistical tests confirm the existence of significant seasonal differences between contrasting periods, and multivariate analyses indicate that municipal waste variability is more closely associated with temporal factors and with the socioeconomic indicator considered in this study (average monthly net wage), while climatic variables show weaker associations. From an operational perspective, the results highlight the need to seasonally adjust municipal waste collection, transportation, and treatment capacities, particularly during peak generation periods. By providing a detailed case study at the county level, based on real data, the research contributes to the literature on the seasonality of municipal waste and supports evidence-based management decisions at the local and regional levels, in line with European policy objectives.