Characterization and pollution potential of leachate from urban landfills during dry and wet periods in arid regions

Leachate originating from municipal solid waste landfills poses a serious contamination threat to public health. The study performed a bio-physicochemical characterization of leachate from two landfills in Oman, i.e., Multaqa landfill leachate (MLL) and Barka landfill leachate (BLL) before and after rainfall. Samples were characterized for ninety-two (92) parameters. Additionally, the leachate pollution index (LPI) was estimated to assess. The study found a high value of the leachate parameters without any rainfall incidents. Pearson correlations (+/- ve) have to be seen more than 90% in all cases, which is a strong association (r>0.75) for the measured parameters in both MLL and BLL. Rainfall significantly reduced the concentrations of organic contaminants and solids in leachate due to dilution. The study revealed about 18-29% and 14-28% reductions in the LPI sub-index for organic and inorganic contaminants, respectively, after the rainfall. The overall LPI values were higher compared to similar findings from the literature. Such deviations could be attributed to the unsegregated nature of solid wastes, resulting in the formation of contaminants or from the disposal of a high volume of solid wastes in a smaller area. Therefore, the study recommends efficient management strategies of landfills to reduce potential leachate groundwater contamination.