Enhancing the Clarification of Azzaba Landfill Leachate Using Biocoagulants with Optimization by Box Behnken Design

This study focuses on optimizing the coagulation-flocculation process for treating pollutants in the leachate from Azzaba landfill, utilizing natural coagulants: walnut shells, Moringa oleifera seeds, and Opuntia ficus-indica leaves. Walnut shells, at pH 4, a coagulant dosage of 12g/L, 300rpm stirring speed, and 25 minutes of treatment, demonstrated remarkable reductions in turbidity (83.92%) and suspended solids (92%). Opuntia ficus-indica, operating under pH 6, a coagulant dosage of 10g/L, 300rpm stirring speed, and 20 minutes of treatment, achieved significant reductions in turbidity (86%) and suspended solids (90%). Moringa oleifera, functioning at pH 3, a coagulant dosage of 6g/L, 300rpm stirring speed, and 35 minutes of treatment, exhibited substantial decreases in turbidity (91%) and suspended solids (85%). Adding lime and starch as flocculants further enhanced treatment efficiency, particularly in turbidity reduction. The Box Behnken design (BBD) optimization highlighted the outstanding effectiveness of coagulants, emphasizing their exceptional performance in turbidity and suspended solids removal. However, maintaining pH stability remains pivotal for optimal results. These findings underscore the efficiency of natural coagulants, especially walnut shells, in leachate treatment, showcasing a promising approach to environmental remediation.