According to the extended definition of “biomass” given in the EU Directive 2009/28/EC (on renewable energy sources), our attention was recently focused on the assessment and quantification of the biomethane potential (BMP) of: (1) some agricultural residues having a peculiar relevance at Italian national scale, i.e., grape-seeds and plum-stones; (2) a flowering plant, scientifically classified as Isatis Tinctoria L., widely used for the indigo blue colour extraction in the Urbino dukedom (Marche Region, Central Italy, Adriatic Sea side) during the Renaissance epoch. Concerning the Isatis Tinctoria L., our research intention is to consider innovative options for its reevaluation, including the potential bioenergy recovery. The anaerobic digestion tests on the selected substrates were performed in batch mode and at mesophilic conditions. A lab-scale system representing a variant of the Owen et al. (1979) serum-bottle technique was employed in these experiments. A digested sludge from a large wastewater treatment plant was used as the inoculum. The feeding mixtures were prepared observing some precise inoculum-to-substrate (I/S) ratios as defined on a volatile solids (VS) basis. The specific methane yield (SMY) values (expressed as Nml CH4 gVS-1), obtained for the aforementioned residues, resulted not so strictly dependent on the I/S ratio as highly connected with the particular biochemical composition of the feeding materials. For instance, concerning the grape-seeds, the I/S ratio of 1 gave arise to a higher methane production yield as compared with the I/S ratio of 0.5, probably because of a major presence of bacteria in the overall mixture providing a more efficient biochemical degradation of the grape-seed oils. On the contrary, the I/S ratio of 0.5 improved appreciably the methane yield of the plum-stones, rather than the I/S of 1. The increasing of the substrate concentration, indeed, could ensure a broader availability of organic substances for the bacteria, considering that plum-stone is noticeably characterized by a consistent lignin content. Within an integrated research approach, detailed chemical-physical characterisations of the obtained digestates were also carried out, in particular: (1) chemical analyses (COD, calcium carbonate, elemental analysis, and IR spectroscopy); and (2) thermal analyses (differential thermal analysis and thermogravimetric analysis DTA/TG).

Combined BMP Tests and Digestate Characterisation of Peculiar Agricultural Substrates in Italy

TATANO, FABIO;
2012-01-01

Abstract

According to the extended definition of “biomass” given in the EU Directive 2009/28/EC (on renewable energy sources), our attention was recently focused on the assessment and quantification of the biomethane potential (BMP) of: (1) some agricultural residues having a peculiar relevance at Italian national scale, i.e., grape-seeds and plum-stones; (2) a flowering plant, scientifically classified as Isatis Tinctoria L., widely used for the indigo blue colour extraction in the Urbino dukedom (Marche Region, Central Italy, Adriatic Sea side) during the Renaissance epoch. Concerning the Isatis Tinctoria L., our research intention is to consider innovative options for its reevaluation, including the potential bioenergy recovery. The anaerobic digestion tests on the selected substrates were performed in batch mode and at mesophilic conditions. A lab-scale system representing a variant of the Owen et al. (1979) serum-bottle technique was employed in these experiments. A digested sludge from a large wastewater treatment plant was used as the inoculum. The feeding mixtures were prepared observing some precise inoculum-to-substrate (I/S) ratios as defined on a volatile solids (VS) basis. The specific methane yield (SMY) values (expressed as Nml CH4 gVS-1), obtained for the aforementioned residues, resulted not so strictly dependent on the I/S ratio as highly connected with the particular biochemical composition of the feeding materials. For instance, concerning the grape-seeds, the I/S ratio of 1 gave arise to a higher methane production yield as compared with the I/S ratio of 0.5, probably because of a major presence of bacteria in the overall mixture providing a more efficient biochemical degradation of the grape-seed oils. On the contrary, the I/S ratio of 0.5 improved appreciably the methane yield of the plum-stones, rather than the I/S of 1. The increasing of the substrate concentration, indeed, could ensure a broader availability of organic substances for the bacteria, considering that plum-stone is noticeably characterized by a consistent lignin content. Within an integrated research approach, detailed chemical-physical characterisations of the obtained digestates were also carried out, in particular: (1) chemical analyses (COD, calcium carbonate, elemental analysis, and IR spectroscopy); and (2) thermal analyses (differential thermal analysis and thermogravimetric analysis DTA/TG).
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11576/2529397
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