Tratamento de vinhaça em reator anaeróbio operado em batelada seqüencial contendo biomassa imobilizada sob condições termofílicas e mesofílicas / Vinasse treatment in anaerobic sequencing batch reactor with immobilized biomass under thermophilic and mesophilic conditions

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

In this work, the viability of the thermophilic (55 Celsius degrees) and mesophilic (35 Celsius degrees) anaerobic treatment of sugar cane vinasse in an anaerobic sequencing batch reactor containing immobilized biomass (ASBBR) was evaluated. The reactor was filled with polyurethane foam matrices inoculated with a granular sludge taken from an UASB reactor treating poultry slaughterhouse wastewater operating at 35 Celsius degrees. The mixing was provided by means of a mechanical mixer operated at 300 rpm. During the operation at thermophilic temperatures, the cycle time of the ASBBR was changed in the different operating phases according to the influent concentration. At the mesophilic temperatures, the reactor operated at a fixed cycle time of 24 hours. Monitoring analyses included the determinations of chemical oxygen demand (COD), total volatile acids, bicarbonate alkalinity and pH of influent and effluent samples, and along the cycles. The microbial community development inside the reactor was monitored during all the experimental phases by means of microscopic observations. During the adaptation period, the biomass of the thermophilic reactor was fed with low concentration vinasse with 0.3 to 1.0 gCOD/L. The biomass was considered adapted to the thermophilic temperature after 50 days. The enrichment of the mesophilic reactor with methanogenic biomass lasted 21 days. In this period the reactor was fed with ethanol based substrate (2.5 gDQO/L) and minerals. The applied organic loads in the thermophilic reactor were 0.85, 2.16, 4.59, 3.95, 4.07, 6.0 and 5.24 gDQO/L.d reaching average removal efficiencies of 43 + OU -7.9%, 73 + OU -7.0%, 68 + OU -19.2%, 78 + OU -9.0%, 55 + OU -10.0%, 46 + OU -19.0% and 75 + OU -7.5%, respectively. The mesophilic reactor was able to accommodate organic loads of 2.85, 6.4, 7.9, 10.5, 22.2 and 36.0 gCOD/L.d with average removal efficiencies of 75 + OU -8.7%, 76 + OU -9.6%, 78 + OU -4.1%, 78 + OU -7.7%, 85 + OU -4.1% and 79 + OU -2.1%, respectively. Therefore, the treatment of sugar cane vinasse in the ASBBR under mesophlic temperatures performed better than at thermophilic conditions. The microbiological observations of biomass samples indicated that methanogenic Methanosarcina-like archaea and fluorescent rods predominated at thermophilic temperatures, whereas the Methanosaeta-like archaea predominated in the reactor under mesophilic temperatures.

ASSUNTO(S)

mesophilic archeae thermophilic arquéia vinasse vinhaça termofílica mesofílica asbbr asbbr anaerobic process processo anaeróbio

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