Treatment of Landfill Leachate by coagulation-flocculation [Traitement des lixiviats de décharge par coagulation-floculation]

Coagulation -flocculation is among the techniques commonly used for the treatment of discharges of leachate from landfills. the present work shows the results obtained during the processing of leachate collected at the landfill of the city of fez by the process of coagulation- flocculation using four coagulants such as: lime ca(oh)2,ferric chloride fecl3,the ferric sulfate fe2(so4)3 and aluminum sulfate al2(so4)3. the process efficiency is measured in terms of metallic elements,turbidity,sludge production and color removal. treatment with lime ca(oh)2 allowed a significant discoloration and turbidity removal of 99 % while producing a sludge volume of 647ml/l. as to treatment with fecl3,the results showed a 75% removal of turbidity and low production of settled sludge (245 ml/l). treatment with fe2(so4)3 has a 79 % reduction in turbidity and produces a volume of 264 ml/l of settled sludge which is close to that produced by fecl3 (245 ml/l). furthermore,al2(so4)3 having a turbidity removal of about 97 % and a volume of decanted sludge slightly lower than the product during the treatment with lime (568ml/l). regarding the analysis of metallic elements,the results showed that a substantial removal of the metallic elements in particularly elements as,cd,cr,cu,fe,mn,ni,pb,zn and sb. treatment with lime has shown a greater or lesser affinity for cr (90%) fe (96 %) and mn (99 %). the ferric chloride and ferric sulfate allows the elimination of most of the metal elements with a high affinity for cd,cu,ni,cr and zn. the aluminum sulfate is very suitable for the removal of nickel pb,cr,zn,respectively 95 %,94 %,84 % and 93.