Exploring the performance limits of a sulfidogenic UASB during the long-term use of crude glycerol as electron donor
| Autor: | Mabel Mora, Eva Fernandez Palacios, Maria del Mar Baeza Labat, Francisco Javier Lafuente Sancho, David Gabriel |
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| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Glycerol
Environmental Engineering 010504 meteorology & atmospheric sciences Sulfide chemistry.chemical_element Electrons Electron donor 010501 environmental sciences Waste Disposal Fluid 01 natural sciences Methane Carbon sink chemistry.chemical_compound Environmental Chemistry SO2 valorization Sulfate-reducing bacteria Sulfate Waste Management and Disposal Effluent UASB 0105 earth and related environmental sciences chemistry.chemical_classification Crude glycerol Sewage Pollution Sulfur Bioscrubber chemistry Environmental chemistry SRB |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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