title: Where does the removal of H₂S from biogas occur in microaerobic reactors?
abstract: In order to maximise the efficiency of biogas desulphurisation and reduce the oxygen cost during microaerobic digestion, it is essential to know how the process occurs. For this purpose, a reactor with a total volume of 266 L, treating 10 L/d of sewage sludge, was operated with 25.0 L and without headspace. Under anaerobic conditions, the H2S concentration in the biogas varied between 0.21 and 0.38%v/v. Next, O2 was supplied from the bottom of the reactor. At 0.25-0.30 NLO₂/Lfed, the biogas was entirely desulphurised, and its O₂ content remained below 1.03%v/v, when the digester had 25.0 L of gas space. However, with almost no headspace, the H2S content in the biogas fluctuated from 0.08 to 0.21%v/v, while the average O2 concentration was 1.66%v/v. The removed H2S accumulated in the outlet pipe of the biogas in the form of S(0) due to the insufficient headspace.
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: pena@iq.uva.es.
authors.forename: M
authors.initials: M
authors.lastname: Peña
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: D001421:Bacteria, Anaerobic / Q000378:metabolism*; D056804:Biofuels / Q000032:analysis*; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors / Q000382:microbiology*; D002849:Chromatography, Gas; D006862:Hydrogen Sulfide / Q000302:isolation & purification* / Q000378:metabolism; D010100:Oxygen / Q000032:analysis; D012037:Refuse Disposal / Q000295:instrumentation* / Q000379:methods*; D012722:Sewage / Q000382:microbiology*
chemical_list: D056804:Biofuels; D012722:Sewage; D010100:Oxygen; D006862:Hydrogen Sulfide
keywords: Biogas desulphurisation; Headspace; Hydrogen sulfide; Microaerobic digestion