Treatment of Landfill Leachate by Heterogeneous Catalytic Ozonation with Granular Faujasite Zeolite

Abstract

Ozonation, combined with suitable catalyst represents an interesting option in removing poorly degraded pollutants from stabilized landfill leachate. Therefore, this study aimed to eliminate chemical oxygen demand (COD), color, and ammoniacal nitrogen, and to improve the biodegradability of stabilized landfill leachate using the heterogeneous catalytic ozonation with natural zeolite (Faujasite) in comparison with solo ozone or adsorption treatment. First, Faujasite was characterized and used in batch studies to find the optimum removal, followed by isotherm and kinetic studies to understand the mechanism. Next, ozonation as sole treatment under different operating conditions of pH and reaction time was applied. Subsequently, Faujasite was combined in the same reactor with the ozone in heterogeneous catalytic ozonation to enhance the treatment performance. Removal for ammonia, COD, and color by ozone as sole treatment were 29%, 47%, and 90%, respectively, compared with 63%, 66%, and 60% reductions by Faujasite as adsorbent. Heterogeneous catalytic ozonation with Faujasite shows ∼64% and 93% of the COD and color removal at pH 11. At this pH, Faujasite promoted ozone degradation, whereas 35% of ammonia was removed at pH 5 because of the interaction between direct ozone and pollutants on the Faujasite surface. Leachate biodegradability also improved from 0.016 to 0.1 after the combined treatment. Faujasite augmented in the ozonation improved the removal of pollutants and simultaneously enhanced the biodegradability of the stabilized landfill leachate.