title: Oxygen transfer to slurries treated in a rotating drum operated at atmospheric pressure.
abstract: The objective of this work was to determine (1) the effect of rotational speed (N) and lifters on the oxygen transfer coefficient (k (L)) of a mineral solution and (2) the effect of solids concentration of a slurry soil-mineral solution on k (L), at a fixed value N (0.25 s(-1)); in both cases the treatment was carried out in an aerated rotating drum reactor (RDR) operated at atmospheric pressure. First, the k (L) for the mineral solution was in the range 6.38 x 10(-4)-7.69 x 10(-4) m s(-1), which was of the same order of magnitude as those calculated for closed rotating drums supplied with air flow. In general, k (L) of RDR implemented with lifters was superior or equal to that of RDR without lifters. For RDR implemented with lifters, k (L) increased with N in the range 6.65 x 10(-4)-10.51 x 10(-4) m s(-1), whereas k (L) of RDR without lifters first increased with N up to N = 0.102 s(-1), and decreased beyond this point. Second, regarding soil slurry experiments, an abrupt fall of k (L) (ca. 50%) at low values of the solid concentration (C (v)) and an asymptotic pattern at high C (v) were observed at N = 0.25 s(-1). These results suggest that mass transfer phenomena were commanded by the slurry properties and a semi-empirical equation of the form Sh = f(Re, Sc) seems to corroborate this finding.
authors.affiliation: Departamento de Biotecnología y Bioingeniería, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional CINVESTAV-IPN, México, DF, Mexico. jbarrera@cinvestav.mx
authors.forename: Josefina
authors.initials: J
authors.lastname: Barrera-Cortés
authors.forename: Efraín
authors.initials: E
authors.lastname: Manilla-Pérez
authors.forename: Héctor M
authors.initials: HM
authors.lastname: Poggi-Varaldo
mesh_terms: D001272:Atmosphere; D001420:Bacteria, Aerobic / Q000378:metabolism*; D019149:Bioreactors / Q000382:microbiology*; D018929:Cell Culture Techniques / Q000295:instrumentation* / Q000379:methods; D003198:Computer Simulation; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008954:Models, Biological; D010100:Oxygen / Q000737:chemistry / Q000493:pharmacokinetics*; D010865:Pilot Projects; D011312:Pressure; D012037:Refuse Disposal / Q000379:methods; D012399:Rotation; D012722:Sewage / Q000382:microbiology*
chemical_list: D012722:Sewage; D010100:Oxygen