Characterization of a leachate from a sanitary intermunicipal landfill. Analysis of the content in metals at several stages of the wastewater treatment plant.

Abstract

In this work the content in seven metals was analysed in samples from a leachate, collected in a sanitary intermunicipal landfill. Samples were collected in three stages of the wastewater treatment plant, just before the biological treatment, just after the biological treatment and from the ultrafiltration permeate. Pb, Cr, Cu, Fe, Mn, Cd, Zn content was determined. Fe was the most abundant of the analysed metals with 22.2 mgL-1 in the samples before the, 41.3 mgL-1 after the biological treatment and 4.0 mgL-1 in the ultrafiltration permeate. Cd content was below detection limit of AAS. Zn, Cu, Cr, Mn and Pb contents are between those limits. The values obtained are in accordance with the range reported in the literature for the analyzed metals. The results obtained suggest that there is a higher concentration of metals in the fraction after the biological treatment, consistent with the fact that there is a recirculation of the ultrafiltration concentrate to this stage. The permeate of ultrafiltration presents the lowest metal content, which indicate an efficiency of the treatment stages so far in metal removal. From the point of view of metal recovery, the best stage to collect samples seem to be after the biological treatment.