Exploring the performance limits of a sulfidogenic UASB during the long-term use of crude glycerol as electron donor
Fernandez Palacios, Eva (Universitat Autònoma de Barcelona. Departament d'Enginyeria Química, Biològica i Ambiental)
Lafuente Sancho, Francisco Javier (Universitat Autònoma de Barcelona. Departament d'Enginyeria Química, Biològica i Ambiental)
Mora Garrido, Mabel (Universitat Autònoma de Barcelona. Departament d'Enginyeria Química, Biològica i Ambiental)
Gabriel, David (Universitat Autònoma de Barcelona. Departament d'Enginyeria Química, Biològica i Ambiental)

Date:	2019
Abstract:	SOx contained in flue gases and S-rich liquid effluents can be valorized to recover elemental sulfur in a two-stage bioscrubbing process. The reduction of sulfate to sulfide is the most crucial stage to be optimized. In this study, the long-term performance of an up-flow anaerobic sludge blanket (UASB) reactor using crude glycerol as electron donor was assessed. The UASB was operated for 400 days with different sulfate and organic loading rates (SLR and OLR, respectively) and a COD/S-SO42− ratio ranging from 3. 8 g O2 g−1 S to 5. 4 g O2 g−1 S. After inoculation with methanogenic, granular biomass, the competition between sulfate-reducing and methanogenic microorganisms determined to what extent dissolved sulfide and methane were produced. After the complete washout of methanogens, which was revealed by next-generation sequencing analysis, the highest S-EC was reached in the system. The highest average sulfate elimination capacity (S-EC = 4. 3 kg S m−3d−1) was obtained at a COD/S-SO42− ratio of 5. 4 g O2 g−1 S and an OLR of 24. 4 kg O2 m−3d−1 with a sulfate removal efficiency of 94%. The conversion of influent COD to methane decreased from 12% to 2. 5% as the SLR increased while a large fraction of acetate (35% of the initial COD) was accumulated. Our data indicate that crude glycerol can promote sulfidogenesis. However, the disappearance of methanogens in the long-term due to the out competition by sulfate reducing bacteria, lead to such large accumulation of acetate.
Grants:	Ministerio de Economía y Competitividad CTQ2015-69802-C2-1-R
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, i la comunicació pública de l'obra, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original. No es permet la creació d'obres derivades.
Language:	Anglès
Document:	Article ; recerca ; Versió acceptada per publicar
Subject:	Bioscrubber ; Carbon sink ; Crude glycerol ; SO2 valorization ; SRB ; UASB
Published in:	Science of the total environment, Vol. 688 (October 2019) , p. 1184-1192, ISSN 1879-1026

DOI: 10.1016/j.scitotenv.2019.06.371
PMID: 31726549

Postprint 27 p, 993.8 KB

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