Keywords: landfill leachate, coagulation, flocculation, physicochemical treatment, leachate treatment, Mexico, organic matter, COD, chemical oxygen demand, ferric chloride, ferrous sulphate
Physico–chemical treatment of type III leachates from a landfill in Tuxtla Gutiérrez, Chiapas, Mexico
This project set out to study the nature and composition of leachate produced in the sealed off area of the landfill in the city of Tuxtla Gutiérrez, Chiapas, Mexico. The leachate was found to be mature, type III leachate, as determined by its biodegradability and therefore, experiments using the coagulation–flocculation process were performed to treat the leachate. The two coagulants used were: Ferric Chloride (FeCl3) and Ferrous Sulphate (FeSO4), applied in different doses (1.4, 1.6 and 1.8 g/L), using 3 different pHs (4, 5 and 6), in a 3² experimental arrangement. To assess the efficiency of the process, the organic charge was quantified in terms of chemical oxygen demand (COD). The results showed that FeCl3 was considerably more effective than FeSO4 in the removal of organic matter. It was also observed that the best removal efficiencies measured in COD (67%) were obtained at pH 6 using a dose of 1.4 g/L of FeCl3.