Composting Plant Leachate Treatment by Coagulation-Flocculation Process

Abstract: This experimental study was conducted to investigate the effect of treatment of composting plant leachate by a coagulation-flocculation process. The effects of different dosages of coagulant and different pH values on the coagulation processes were compared. Ferric chloride and aluminium sulphate (alum) were tested as conventional coagulants. The experimental results show that a 18 % removal of COD and 90% removal of heavy metals can be attained at pH 6.5 (optimum for alum) with the addition of 1400 mg L alum and-1 a 28 % removal of COD and 86 % removal of heavy metals can be attained at pH 10 (optimum for ferric chloride) with the addition of 2000 mg L ferric chloride. The comparison of these values with the Iranian guideline-1 for effluent discharge shows that the concentration of heavy metals in leachate did not exceed the maximum values allowed. Key word: Solid Waste Leachate Chemical treatment Heavy metals INTRODUCTION The specific composition of leachates determines its The growing production of domestic and industrial landfill leachates often involve a combination of wastes in the world causes serious disposal problems. appropriate techniques. They are designed as modular, Solid waste landfill sites are often defined as hazardous multi-stage units, capable of coping with the changing and heavily polluted wastewaters with considerable leachate characteristics over the years. Several processes,