In the last period, anaerobic digestion (AD) is acquiring great interest as a form of waste management, in particular for organic fraction of municipal solid waste (OFMSW) because of its contribution to energy recovery and to reduction of environmental pollution. Vulnerability of microorganism involved in AD process, mainly in the methanogenic step, can cause low methane yields and instability of the bioconversion process. Some literature studies showed that the use of pyrolysis char in AD could be advantageous thanks to its structural properties and surface chemistry affecting both the stability of microorganism consortia and digestion media. In this work an attempt to correlate amount of char added to the AD process of food waste (FW) to the performance of the process was made. Char was obtained from slow pyrolysis of Populus nigra up to 873 K at 5 °C/min. AD of a model mixture representing a typical domestic FW was carried out in a batch bioreactor (crimped pyrex bottles with perforable butyl rubber septa) in mesophilic conditions (37 °C). Different amounts of char (wbiochar/wFW) were added to the feedstock: 1, 4 and 10 wt%. Both the liquid and the gas phase were analyzed and monitored during the AD process: microbial growth, pH, biogas volume and composition. Experimental results, reported in Figure 1, have highlighted that the methane yields and the methane concentration in the produced biogas were considerably higher at increasing char concentration. Moreover, hydrogen is also produced in presence of biochar. SEM micrographs and FTIR spectra of the resulting char were produced in order to investigate the nature of the interaction between char and the microbial consortia involved in the bioconversion process.

Enhancement of Methane production during Biochar-Assisted Anaerobic Digestion

C. Florio
;
S. Dumontet;V. Pasquale;
2017

Abstract

In the last period, anaerobic digestion (AD) is acquiring great interest as a form of waste management, in particular for organic fraction of municipal solid waste (OFMSW) because of its contribution to energy recovery and to reduction of environmental pollution. Vulnerability of microorganism involved in AD process, mainly in the methanogenic step, can cause low methane yields and instability of the bioconversion process. Some literature studies showed that the use of pyrolysis char in AD could be advantageous thanks to its structural properties and surface chemistry affecting both the stability of microorganism consortia and digestion media. In this work an attempt to correlate amount of char added to the AD process of food waste (FW) to the performance of the process was made. Char was obtained from slow pyrolysis of Populus nigra up to 873 K at 5 °C/min. AD of a model mixture representing a typical domestic FW was carried out in a batch bioreactor (crimped pyrex bottles with perforable butyl rubber septa) in mesophilic conditions (37 °C). Different amounts of char (wbiochar/wFW) were added to the feedstock: 1, 4 and 10 wt%. Both the liquid and the gas phase were analyzed and monitored during the AD process: microbial growth, pH, biogas volume and composition. Experimental results, reported in Figure 1, have highlighted that the methane yields and the methane concentration in the produced biogas were considerably higher at increasing char concentration. Moreover, hydrogen is also produced in presence of biochar. SEM micrographs and FTIR spectra of the resulting char were produced in order to investigate the nature of the interaction between char and the microbial consortia involved in the bioconversion process.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11367/71447
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