ANOVA-based comparative study for landfill age and climate impacts on landfill leachate characteristics

This study investigates the combined effects of precipitation and landfill age on leachate characteristics using one-way ANOVA to identify statistically significant differences among impact groups. The primary objective is to evaluate how climatic conditions and landfill age jointly influence both organic and inorganic leachate constituents. The results indicate that precipitation acts as a dominant controlling factor, although its influence is strongly modulated by landfill age and site-specific conditions. In low-precipitation climates, statistically significant temporal variations were observed in organic parameters (COD, BOD, and BOD/COD), particularly during the early stages of landfilling. In contrast, no statistically significant age-related differences were detected in high-precipitation regions, suggesting that dilution and wash-out mechanisms dominate over time-dependent biological processes. For inorganic constituents, chloride and ammonia exhibit weak or inconsistent statistical differences, while calcium and selected metals show more complex, non-linear behavior. These findings demonstrate that one-way ANOVA is an effective tool for identifying parameters sensitive to climatic and temporal factors, while also revealing parameters that are statistically unaffected by such influences. Overall, the results confirm that landfill age plays a significant role in shaping leachate composition in dry climates, whereas hydrological processes are the dominant controlling factors in wet climates.