Two experimental runs, lasting 28 and 44 days, respectively, were designed to simulate a miniaturized landfill environment by using specific prototypes, each one consisting of: (i) a digester, representing the landfill waste body under predominant anaerobic degradation conditions, connected to (ii) a soil column, representing the landfill cover soil. These experiments aimed to investigate the compositional changes in biogas, generated in the digesters, passing through treated and untreated soil columns. Adopting a circular economy approach aimed at transforming waste streams into resources, landfill leachate (LL) and dewatered sewage sludge (SS) were used for the treatment of the soil columns. In both experiments, gas samples were periodically collected from the headspace of the digesters and from four different sampling ports placed along the soil columns. Furthermore, the flow of the generated biogas and the temperature inside the digester were monitored. Isotope analyses of CH4 and CO2 highlighted that CH4 was markedly affected by isotope fractionation due to biodegradation processes in the treated soil columns, although not showing any evident vertical trend. The contents of alkanes, aromatic, cyclic, terpenes, halogenated, and S-substituted compounds decreased upward along the vertical profiles of the treated soils, whilst O-substituted compounds relatively increased. The second experimental run highlighted how the efficacy in biogas abatement by the treated soil was influenced to a large extent by the addition with dewatered SS as compared with LL recirculation. Such laboratory experiments indicated that a particular landfill cover soil treated with dewatered SS is expected to optimize the efficacy in degrading CH4 and selected VOCs with respect to untreated cover soil. Future works may be aimed at testing the effective landfill gas (LFG) attenuation capacity of this developed biocover soil system at a full-scale landfill.
Attenuation of volatile inorganic and organic compounds in landfill cover soils treated with sewage sludge and landfill leachate
Fabio Tatano;
2023
Abstract
Two experimental runs, lasting 28 and 44 days, respectively, were designed to simulate a miniaturized landfill environment by using specific prototypes, each one consisting of: (i) a digester, representing the landfill waste body under predominant anaerobic degradation conditions, connected to (ii) a soil column, representing the landfill cover soil. These experiments aimed to investigate the compositional changes in biogas, generated in the digesters, passing through treated and untreated soil columns. Adopting a circular economy approach aimed at transforming waste streams into resources, landfill leachate (LL) and dewatered sewage sludge (SS) were used for the treatment of the soil columns. In both experiments, gas samples were periodically collected from the headspace of the digesters and from four different sampling ports placed along the soil columns. Furthermore, the flow of the generated biogas and the temperature inside the digester were monitored. Isotope analyses of CH4 and CO2 highlighted that CH4 was markedly affected by isotope fractionation due to biodegradation processes in the treated soil columns, although not showing any evident vertical trend. The contents of alkanes, aromatic, cyclic, terpenes, halogenated, and S-substituted compounds decreased upward along the vertical profiles of the treated soils, whilst O-substituted compounds relatively increased. The second experimental run highlighted how the efficacy in biogas abatement by the treated soil was influenced to a large extent by the addition with dewatered SS as compared with LL recirculation. Such laboratory experiments indicated that a particular landfill cover soil treated with dewatered SS is expected to optimize the efficacy in degrading CH4 and selected VOCs with respect to untreated cover soil. Future works may be aimed at testing the effective landfill gas (LFG) attenuation capacity of this developed biocover soil system at a full-scale landfill.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
