Evolution of microorganisms in thermophilic-dry anaerobic digestion.
Microbial population dynamics were studied during the start-up and stabilization periods in thermophilic-dry anaerobic digestion at lab-scale. The experimental protocol was defined to quantify Eubacteria and Archaea using Fluorescent in situ hybridization (FISH) in a continuously stirred tank reactor (CSTR), without recycling solids. The reactor was subjected to a programme of steady-state operation over a range of the retention times from 40 to 25 days, with an organic loading rate between 4.42 and 7.50 kg volatile solid/m3/day. Changes in microbial concentrations were linked to traditional performance parameters such as biogas production and VS removal. The relations of Eubacteria:Archaea and H2-utilising methanogens:acetate-utilising methanogens were 88:12 and 11:1, respectively, during start-up stage. Hydrogenotrophic methanogens, although important in the initial phase of the reactor start-up, were displaced by acetoclastic methanogens at steady-state, thus their relation were 7:32, respectively. The methane yield coefficient, the methane content in the biogas and VS removal were stabilized around 0.30 LCH4/gCOD, 50% and 80%, respectively. Methanogenic population correlated well with performance measurements.
Department of Chemical Engineering, Food and Environmental Technologies, Faculty of Marine and Environmental Sciences, University of Cadiz, Campus Rio San Pedro s/n, 11510 Puerto Real, Cadiz, Spain. blanca.montero@uca.es <blanca.montero@uca.es>
B
B
Montero
J L
JL
Garcia-Morales
D
D
Sales
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R
Solera
D000693:Anaerobiosis; D001105:Archaea / Q000235:genetics / Q000254:growth & development*; D019149:Bioreactors; D003470:Culture Media; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development*; D017744:Medical Waste Disposal; D009584:Nitrogen / Q000378:metabolism; D015345:Oligonucleotide Probes; D009930:Organic Chemicals / Q000378:metabolism; D011157:Population Dynamics; D014865:Waste Disposal, Fluid / Q000379:methods
D003470:Culture Media; D017744:Medical Waste Disposal; D015345:Oligonucleotide Probes; D009930:Organic Chemicals; D009584:Nitrogen