Artículos de revistas
Real evidence about zeolite as microorganisms immobilizer in anaerobic fluidized bed reactors
Fecha
2007Registro en:
Process Biochemistry 42 (2007) 721–728
doi:10.1016/j.procbio.2006.12.004
Autor
Fernández, N.
Montalvo, S.
Fernández Polanco, F.
Guerrero, L.
Cortés, I.
Borja, R.
Sánchez, E.
Travieso, L.
Institución
Resumen
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 8C). 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.