Development and implementation of a new adjuvant-organic coagulant in the process of coagulation-flocculation of the leachate from a landfill

Abstract

The only alternative for the final disposal of solid wastes in Mexico is the sanitary landfill, but the leachate generated represents a water and soil contamination risk. This work had the purpose of determining the coagulation-flocculation potential of several mixtures made up of variable proportions of banana starch, aluminum sulfate and clays (LASA 55; LASA 73; LASAB 23530 and LASAR 23530). To evaluate the coagulation-flocculation effectiveness, controls were run with aluminum sulfate and ferric chloride. Leachate was pretreated and jar tests were performed, measuring control components as Turbidity, Color, Chemical Oxygen Demand (COD) Hydrogen Potential (pH), Total Suspended Solids (TSS) and Conductivity. Turbidity was reduced to less than 5 NTU with 75 mg/L in two treatments (LASA 55 and aluminum sulfate). The highest color removal was obtained with ferric chloride, followed by LASA 55 and aluminum sulfate, LASAB 23530 and LASA 73, the lowest being that with LASAR 23530. The mixtures based on starch plus aluminum sulfate showed a low COD removal and, in comparison with LASAR, the conventional coagulants presented a better removal. A very similar correlation was observed between TSS and conductivity. The results obtained in this work determined the feasibility of applying mixtures with coagulant properties for leachate treatment and for future tests in the treatment of industrial or municipal wastewaters.