ABSTRACT
No presente trabalho foi estudada a influência das condições de aeração no tratamento de efluentes fenólicos com biofilmes. Os ensaios foram realizados com efluente sintético para simular dejetos industriais com elevadas concentrações de fenol. Foram testadas vazões de aeração de 0,7, 1,6, 2,3 vvm na cinética de biodegradação de fenol. Nas melhores condições testadas, quais sejam: reator de leito empacotado, com suporte de esferas de cerâmica e vazão de 2,3 vvm, foi atingida eficiência de remoção de fenol de aproximadamente 96 por cento.
Subject(s)
Biodegradation, Environmental , Biofilms , Industrial Effluent Treatment , Activated Sludges/methods , PhenolABSTRACT
The feeding media was studied in a fed-batch process for production of the complex spore-d-endotoxin by B. thuringiensis S93. The microorganism was first cultvated in a initial batch followed by an exponential feeding (m=0,25h(-1)) with concentrated culture media (160 g glucose/L) containing different ratios of glucose and autolysed yeast: 8/7, 8/4 and 8/2 (g/g). The batch culture medium was composed of glucose (8 g/L), autolysed yeast (7g/L) and mineral salts. Sporulation and d-endotoxin production were observed only after the end of feeding. To compare the experiments, batch cultivations were also performed with an initial concentration of 8 g/L of glucose and the same ratio of glucose and autolized yeast. Batch cultivations reached lower concentrations of total biomass and spores than the fed-batch ones and percentagens of sporulation higher than 80 per cente. The 8/7 ratio fed-batch cultivations reached the highest biomass concentration, producing however a very low level of sporulation (27per cent) and virtually no d-endotoxin. Cultivations with 8/4 and 8/2 ratios reached the highest concentrations of spores. In those assays, the maximum spores concentration and the maximum sporulation percentage were 8,3x10(9) spores/mL and 90per cent for the 8/4 ratio and 5,6x10(9) spores/mL and 89per cent for the 8/2 ratio.