Characterization and physico-chemical treatment of El-Kerma (Algeria) landfill leachates by batch adsorption on untreated and chemically activated sawdust

The uncontrolled landfill of El-Kerma (Western Algeria) constitutes a typical example of deterioration of the natural water resources by solid wastes. It generates large volumes of leachate with a strong polluting load (extreme conductivity of 130 mS/cm, extreme chemical oxygen demand (COD) of 28000 mg O(2)/L). Therefore, this leachate should be treated before it is discharged into the environment. The physico-chemical treatment of this landfill leachate by batch adsorption of the organic matter on sawdust activated with a 3 N NaOH solution (SB3) gave a maximum adsorption capacity of 100 mg/g, according to the Langmuir model. This result was obtained for an optimal mass of 0,3 g, with a contact time of 40 min, at pH 11 and a temperature of 55 degrees C. This adsorption is a fast endothermic process, which follows a pseudo first-order kinetic model. Successive treatment tests on untreated leachates have been carried out using a series of five reactors. A 98% abatement rate of the organic matter has been obtained using SB3 sawdust in the outlet of the third reactor. Therefore, the adsorption material used was as effective as other materials widely used in the purification of the effluents.