Real evidence about zeolite as microorganisms immobilizer in anaerobic fluidized bed reactors

Fernández N.; Montalvo, S; Fernandez-Polanco, F; Guerrero, L; Cortes, I; Borja, R; Sanchez E.; Travieso, L

Abstract

Using the scanning electronic microscopy, it was observed that natural zeolite possesses excellent physical characteristics as a support medium in anaerobic fluidized bed reactors (AFBR). Samples for biomass analysis were taken from two identical laboratory-scale AFBR (R-1 and R-2), which were operated with 25% of fluidization. These reactors treated distillery wastewaters (vinasses) at mesophilic temperature (30 ± 2 °C). The experiments were carried out with 0.25-0.50 and 0.50-0.80 mm zeolite particle diameter in reactors R-1 and R-2, respectively. The biomass concentration attached to zeolite in both reactors was found to be in the range of 40-45 g volatile solids/l. COD removal efficiencies as high as 90% were achieved at organic loading rate (OLRs) of up to 20 g COD/l day. The volatile fatty acid (VFA) levels were always lower that the suggested limits for digester failure. The yield coefficient of methane production was 0.29 l CH4(at STP)/g COD consumed and was virtually independent of the OLR applied. A hybridization technique (fluorescence in situ hybridization, FISH) helped determine the predominant anaerobic microorganisms that colonized the natural zeolite, which were found to be Methanosaeta and Methanosarcinaceae, observing a reduced number of sulphate reducing bacteria. The results obtained for reactors R-1 and R-2 were very similar, showing that the particle size did not significantly influence the microbial community immobilized on zeolite. © 2007 Elsevier Ltd. All rights reserved.

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Título según WOS: Real evidence about zeolite as microorganisms immobilizer in anaerobic fluidized bed reactors
Título según SCOPUS: Real evidence about zeolite as microorganisms immobilizer in anaerobic fluidized bed reactors
Título de la Revista: PROCESS BIOCHEMISTRY
Volumen: 42
Número: 4
Editorial: ELSEVIER SCI LTD
Fecha de publicación: 2007
Página de inicio: 721
Página final: 728
Idioma: English
URL: http://linkinghub.elsevier.com/retrieve/pii/S135951130600451X
DOI:

10.1016/j.procbio.2006.12.004

Notas: ISI, SCOPUS