title: Hydrodynamics and mass transfer coefficient in activated sludge aerated stirred column reactor: experimental analysis and modeling.
abstract: The aerated stirred reactor (ASR) has been widely used in biochemical and wastewater treatment processes. The information describing how the activated sludge properties and operation conditions affect the hydrodynamics and mass transfer coefficient is missing in the literature. The aim of this study was to investigate the influence of flow regime, superficial gas velocity (U(G)), power consumption unit (P/V(L)), sludge loading, and apparent viscosity (mu(ap)) of activated sludge fluid on the mixing time (t(m)), gas hold-up (epsilon), and volumetric mass transfer coefficient (k(L)a) in an activated sludge aerated stirred column reactor (ASCR). The activated sludge fluid performed a non-Newtonian rheological behavior. The sludge loading significantly affected the fluid hydrodynamics and mass transfer. With an increase in the U(G) and P/V(L), the epsilon and k(L)a increased, and the t(m), decreased. The epsilon, k(L)a, and t(m), were influenced dramatically as the flow regime changed from homogeneous to heterogeneous patterns. The proposed mathematical models predicted the experimental results well under experimental conditions, indicating that the U(G), P/V(L), and mu(ap) had significant impact on the t(m), epsilon, and k(L)a. These models were able to give the t(m), epsilon, and k(L)a values with an error around +/-8%, and always less than +/-10%.
authors.affiliation: School of Natural and Built Environment, University of South Australia, Mawson Lakes, SA 5095, Australia. bo.jin@unisa.edu.au
authors.forename: Bo
authors.initials: B
authors.lastname: Jin
authors.forename: Paul
authors.initials: P
authors.lastname: Lant
authors.forename: Xiangyu
authors.initials: X
authors.lastname: Ge
mesh_terms: D019149:Bioreactors; D008962:Models, Theoretical; D012212:Rheology / Q000379:methods / Q000706:statistics & numerical data; D012722:Sewage / Q000737:chemistry* / Q000382:microbiology*; D014783:Viscosity
chemical_list: D012722:Sewage