Comparative study of the metal pollution treatment from leachates by physical and biological methods

Abstract

The purpose of this study is a comparative study of the treatment of the metallic pollution of the leachates of the controlled public landfill of the city of Fez by application of the biological processes by aeration and physical by filtration.

The treatment of leachates by aeration allows an accumulation of heavy metals (Al, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) by specific aerobic microorganisms present in the leachate, mainly Mn²⁺ ions with a rate of reduction between 90,8% and 93,3%.

For the physical treatment by infiltration-percolation, we carried out a comparative study of the filtrations on different matrices in order to choose the best filter medium. We used as filter media: three types of clay, fly ash, bottom ash and marine sand. The best reductions in heavy metals are observed with the filtering substrate S₃ formed of clays designated A₁ and fly ash, with concentrations lower than Moroccan standards for direct discharges and reduction rates higher than those found after 7 days of leachate treatment by aeration.