Dr. Valdes-Morales, Hector

This study aims: (a) to characterize the raw leachate generated in the landfill of Fez city, and (b) to evaluate the feasibility to apply an aerobic treatment followed by a Fenton oxidation process. The aerobic treatment was conducted in a suspended grow bioreactor during 60 days. The bioreactor was monitored every 3 days, following the variation of pH, chemical oxygen demand (COD), biochemical oxygen demand (BOD5), turbidity, conductivity, color number (CN), total suspended solids (TSS), nitrates (NO3−-N), nitrites (NO2−-N), and the absorbance values of the UV–vis spectrum. Results showed an elimination of41%, 31%, 50%, 52%, and 37%, on COD, BOD5, color number (CN), NO2−-N and NO3−-N, respectively. Thereafter, a Fenton oxidation process was successfully applied to the biological pre-treated leachate, improving the removal of COD, BOD5 and color to 73%, 99.5% and 94%, respectively.

In this work, the landfll leachate of Fez city (Morocco) is characterized physicochemically and the feasibility to apply a Fenton process is evaluated. A design of experiments based on Box–Behnken combined with a response surface methodology was used to assess the efect of three operating variables (pH, Fe2+ and H2O2 dosages) on two target responses: COD and color removal. The results of the analysis of variances demonstrate that both responses are signifcantly afected by Fe2+ dosage and pH. Statistical and graphical analyses show that maximum efciencies of 85% and 96% are obtained in terms of COD and color removal, respectively, when operating conditions are set in pH=2.8, [Fe2+]=1621 mg L−1 and [H2O2]=2500 mg L−1.

This study aims to investigate the feasibility to apply a coagulation-flocculation process to treat the landfill leachate of the municipal solid waste of Casablanca city (Morocco). Three types of coagulants are assessed: lime (Ca(OH)2), ferric chloride (FeCl3), and alum (Al2(SO4)3). Optimum conditions in terms of the removal of chemical oxygen demand (COD), heavy metals, colour and turbidity contents are determined, using a standard jar test apparatus. Optimum coagulant dosages of 52.5 g Ca(OH)2.l-1, 12 g FeCl3.l-1 and 22.5 g Al2(SO4)3.l-1 are obtained. Lime allows to remove 66.25% of COD, 98% of turbidity, 80% of colour with a low sludge volume generation (30%). When the optimum coagulant dose of FeCl3 is applied a 62.5% of COD, 92.5% of turbidity, 82% of colour are removed with less sludge volume generation (21%).Whereas when Al2(SO4)3 is used 11% COD and 6% of turbidity removal are obtained with a slightly lower sludge volume generation (11%). Regarding the analysis of metallic elements, the results show that a substantial elimination of heavy metals is reached, particularly of Cd, Cr, Cu, Fe, Ni and Pb. Treatment with lime shows a greater affinity to Cr (86%) and lower to Fe (60%). Ferric chloride allows to eliminate most of the detected metal elements with a high affinity toward Cd, Cu, Ni, Cr and Zn. Alum shows to be very suitable for Ni, Pb, Cr elimination with 95 %, 94 % and 93% removal efficiency, respectively. These results show that coagulation-flocculation could be used as a promising process for the pretreatment of landfill leachates of Casablanca city.