Exploratory analysis of seasonal variability and recovery potential of Al, Cu, Fe, and Zn in municipal solid waste incineration bottom ash

The growing demand for metals such as aluminum, copper, iron, and zinc has driven the search for alternative sources. Waste-to-Energy markets enable energy generation and recovery of valuable materials from municipal incinerator bottom ash. This study addresses the occurrence of seasonal variability in metal concentrations, its potential impact on recovery efficiency, and the comparability of incineration residues with natural deposits. Unlike previous research, our approach focused on identifying possible seasonal drivers, interpreting correlations between metals, and comparing bottom ash composition with residues from other plants and natural ores, thereby supporting the concept of sustainable resource management. We analyzed samples collected over 52 weeks to identify seasonal variations in metal concentrations. Seasonal analysis and correlation matrices revealed variability and weak dependencies between metal concentrations. A comparative analysis was performed across European and Asian waste-to-energy facilities. The mean value of aluminum in Poland is 32,481 ppm, while in other cities it ranges from 17,000 to 85,000 ppm. Copper concentrations range from 597 to 25,100 ppm (4567 ppm in Poland). Our results show that the concentrations of analyzed metals vary throughout the year, with colder seasons exhibiting higher levels than warmer periods of the year, highlighting the need for effective recycling strategies.