This study presents an assessment of the kinetic, mass transfer and hydrodynamic parameters of a pilot-scale fixed bed reactor containing immobilized biomass in polyurethane matrices and fed with the effluent of a horizontal-flow fixed bed anaerobic reactor, which was used to treat domestic sewage. It was found that the liquid-solid and intra-particle mass transfer resistances significantly affected the overall oxygen consumption rate and that mechanical agitation could minimize such resistances. The volumetric oxygen transfer coefficient (kLa) values for superficial air velocities between 8.4 cm min(-1) and 57.0 cm min(-1) varied from 20.8 h(-1) to 58.8 h(-1) for tap water, and 16.8 h(-1) to 53.0 h(-1) for the anaerobic pre-treated effluent. The intrinsic oxygen uptake rate was estimated to be 19.9 mgO2 gVSS(-1) h(-1). A first-order kinetic model with residual concentration was considered to adequately represent the COD removal rate, whereas nitrogen conversion was considered to be well represented by a model of pseudo-first-order reaction in series. It was also found that the ammonium conversion to nitrite was the limiting step of the overall nitrogen conversion rate. The hydrodynamic behavior of the reactor was represented by three to four completely mixed reactors in series.
RESUMO-A cefamicina C (cef C) é uma antibiótico β-lactâmico que se destaca por possuir atividade contra as bactérias gram-negativas e ser resistente à ação das enzimas beta-lactamases. O principal objetivo deste trabalho foi aplicar a adsorção de troca iônica para recuperarar a cef C, da fase de topo de um processo de extração líquido-líquido, baseada nos sistemas de duas fases aquosa (SDFA). As condições experimentais utilizadas no processo de extração por SDFA composto por uma mistura de PEG e fosfato, foram: PEG 400, pH 8,0, tamanho de tie-line (TLL) 43 e razão de volume entre as fases (rTLL) de 1,00. As recuperações da fase PEG, foram realizadas por adsorção e dessorção da cef C, com a resina aniônica Amberlite IRA-400 Cl-. As adsorções foram realizadas nas temperaturas de 10, 20 e 25°C e em pH 8,0. Para os experimentos realizados, obteve-se as cinéticas de adsorção e dessorção da cef C na fase de topo (SDFA) e as isotermas de adsorção para as condições de recuperação da cef C.
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