Syngas fermentation to acetate offers a promising solution for its valorisation, particularly when syngas contains a high N concentration, which otherwise impedes the utilisation of syngas biomethanation gaseous product in cogeneration or upgrading units. In this study, continuous lab-scale syngas fermentation assessing the effects of acidic pH and psychrophilic conditions (28 °C and 20 °C) on bioconversion efficiency and anaerobic consortium diversity was studied. The results showed that as temperature and pH decrease, acetate yield increases.
View Article and Find Full Text PDFWaste biomass is considered a promising renewable energy feedstock that can be converted by anaerobic digestion. However, anaerobic digestion application can be challenging due to the structural complexity of several waste biomass kinds. Therefore, coupling anaerobic digestion with thermochemical processes can offset the limitations and convert the hardly biodegradable waste biomass, including digestate residue, into value-added products: syngas and pyrogas (gaseous mixtures consisting mainly of H, CO, CO), bio-oil, and biochar for further valorisation.
View Article and Find Full Text PDFThis study shows biomethane production in a novel two-stage syngas biomethanation consisting of the thermophilic anaerobic digestion of sewage sludge combined with an injection of syngas as the first stage. Since the syngas does not contain enough reducing equivalents, the produced biogas was connected to the second stage consisting of the trickle-bed reactor with the external H addition (ex-situ) to increase the CH content further. The aim was to evaluate the influence of different syngas compositions on the biomethane production in both stages.
View Article and Find Full Text PDFBiotechnol Adv
February 2019
Biogas produced from organic wastes contains energetically usable methane and unavoidable amount of carbon dioxide. The exploitation of whole biogas energy is locally limited and utilization of the natural gas transport system requires CO removal or its conversion to methane. The biological conversion of CO and hydrogen to methane is well known reaction without the demand of high pressure and temperature and is carried out by hydrogenotrophic methanogens.
View Article and Find Full Text PDFHydrogen sulfide is widely known as the most undesirable component of biogas that caused not only serious sensoric and toxic problems, but also corrosion of concrete and steel structures. Many agricultural and industrial waste used in biogas production, may contain a large amount of substances that serve as direct precursors to the formation of sulfide sulfur-sources of hydrogen sulfide in the biogas. Biological desulfurization methods are currently promoted to abiotic methods because they are less expensive and do not produce undesirable materials which must be disposed of.
View Article and Find Full Text PDFAppl Microbiol Biotechnol
March 2015
In this study a completely stirred tank reactor was used to study the effect of sulfide to nitrate (S/N) ratio on sulfide removal while nitrate was used as electron acceptor. Several S/N ratios were studied for this purpose ranging from 0.3 to 2.
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