title: Microaerobic digestion of sewage sludge on an industrial-pilot scale: the efficiency of biogas desulphurisation under different configurations and the impact of O2 on the microbial communities.
abstract: Biogas produced in an industrial-pilot scale sewage sludge reactor (5m(3)) was desulphurised by imposing microaerobic conditions. The H2S concentration removal efficiency was evaluated under various configurations: different mixing methods and O2 injection points. Biogas was entirely desulphurised under all the configurations set, while the O2 demand of the digester decreased over time. Although the H2S removal seemed to occur in the headspace, S(0) (which was found to be the main oxidation product) was scarcely deposited there in the headspace. O2 did not have a significant impact on the digestion performance; the VS removal remained around 47%. Conversely, DGGE revealed that the higher O2 transfer rate to the sludge maintained by biogas recirculation increased the microbial richness and evenness, and caused an important shift in the structure of the bacterial and the archaeal communities in the long term. All the archaeal genera identified (Methanosaeta, Methanospirillum and Methanoculleus) were present under both anaerobic and microaerobic conditions.
authors.affiliation: Department of Chemical Engineering and Environmental Technology, Escuela de Ingenierías Industriales, Sede Dr. Mergelina, University of Valladolid, Dr. Mergelina s/n, 47011 Valladolid, Spain. Electronic address: irisrc@iq.uva.es.
authors.forename: I
authors.initials: I
authors.lastname: Ramos
authors.affiliation: Department of Chemical Engineering and Environmental Technology, Escuela de Ingenierías Industriales, Sede Dr. Mergelina, University of Valladolid, Dr. Mergelina s/n, 47011 Valladolid, Spain. Electronic address: rebeca.perez@iq.uva.es.
authors.forename: R
authors.initials: R
authors.lastname: Pérez
authors.affiliation: Socamex S.A.U (Grupo Urbaser), Polígono Industrial San Cristóbal, C/Cobalto 12, 47012 Valladolid, Spain. Electronic address: mreinosor@socamex.com.es.
authors.forename: M
authors.initials: M
authors.lastname: Reinoso
authors.affiliation: Socamex S.A.U (Grupo Urbaser), Polígono Industrial San Cristóbal, C/Cobalto 12, 47012 Valladolid, Spain. Electronic address: rtorio@socamex.com.es.
authors.forename: R
authors.initials: R
authors.lastname: Torio
authors.affiliation: Department of Chemical Engineering and Environmental Technology, Escuela de Ingenierías Industriales, Sede Dr. Mergelina, University of Valladolid, Dr. Mergelina s/n, 47011 Valladolid, Spain. Electronic address: maria@iq.uva.es.
authors.forename: M
authors.initials: M
authors.lastname: Fdz-Polanco
mesh_terms: D000332:Aerobiosis / Q000187:drug effects; D000693:Anaerobiosis; D001105:Archaea / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D001419:Bacteria / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D044822:Biodiversity; D056804:Biofuels / Q000032:analysis*; D019149:Bioreactors / Q000382:microbiology; D002245:Carbon Dioxide / Q000032:analysis; D058645:Denaturing Gradient Gel Electrophoresis; D006862:Hydrogen Sulfide / Q000032:analysis; D007221:Industry; D008697:Methane / Q000032:analysis; D064307:Microbiota / Q000187:drug effects* / Q000235:genetics; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010100:Oxygen / Q000494:pharmacology*; D010865:Pilot Projects; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012722:Sewage / Q000382:microbiology*; D013455:Sulfur / Q000302:isolation & purification*; D014835:Volatilization
chemical_list: D056804:Biofuels; D012336:RNA, Ribosomal, 16S; D012722:Sewage; D002245:Carbon Dioxide; D013455:Sulfur; D008697:Methane; D010100:Oxygen; D006862:Hydrogen Sulfide
keywords: Biogas desulphurisation; DGGE; Hydrogen sulphide; Microaerobic digestion; Microbial communities