Optimization of Fresh Landfill Leachate Treatment by a Response Surface Methodology

Landfill leachates represent obvious sources of the environment pollution and many processes were used for their treatment. In the present work, we applied coagulation-flocculation process to treat a fresh landfill leachate, originiating from Rabat (Morroco) city, by using ferric chloride as coagulant and a polymeric flocculant. Thus, 25 (5(2)) full factorial experimental design, and response surface methodology, were both employed to determine the optimal coagulant and flocculant dosages. The data showed that at pH = 8.4, the regression coefficients (R-2) obtained for, turbidity, chemical oxygen demand (COD), and color removals, reached, respectively, 0.95, 0.95 and 0.82. The variance analysis (ANOVA) studies have showon that the most significant factor for COD, turbidity and colorization removals was the coagulant dosage. The optimum dosages values as determined by multiple responses optimization, were 12.6 g/L for the coagulant, 63.8 mL/L for the flocculant. In addition, the removal percents obtained for the turbidity, the COD and the colorization, were 94.6%, 35.2% and 94.2% respectively. The overall data indicate that the coagulation-flocculation is an efficient process for treating the landfill leachate.