Determinación del efecto de Cr6+ y Cd2+ sobre la producción de biogás y las características de lixiviado de vertederos biorreactores para la estabilización de materia orgánica residual

Abstract

Bioreactor landfills are an attractive option for municipal solid waste management compared to conventional landfills. It is characterized by the recirculation of the generated leachate, so that the need for leachate treatment is reduced and the rate of biogas generation increases. However, this biogas production can be affected by the concentration of heavy metals such as hexavalent chromium and cadmium, which could have toxic effects on microbiological processes. Three identically started bioreactor landfills were implemented for twelve weeks. They were installed in columns, where successive layers of compost, green waste and sludge from the Ambato wastewater treatment plant were added. The first landfill was used as a control, while the other two were added with hexavalent chromium and cadmium in the ninth week, where a slight stabilization of biogas production occurred. The leachate generated by the columns was collected in a bottom vessel and recirculated to the upper section of the column. The quality of the leachate was analyzed by measuring compounds such as sulphate, sulphide, phosphate, ammonium, magnesium, COD, chromium and cadmium. It was concluded that the addition of hexavalent chromium and cadmium in the bioreactor landfill was not toxic to the microorganisms, but it did affect their operation by causing blockage in the recirculation. This indicates that the presence of these metals did not have an impact on the quality of the leachate and biogas generation.