Estimation of Heterotrophic Biokinetic Parameters in Wastewater Biofilms from Oxygen Concentration Profiles by Microelectrode

2012 ◽  
Vol 29 (6) ◽  
pp. 466-471 ◽  
Author(s):  
Xiao-Hong Zhou ◽  
Jing Liu ◽  
Hui-Min Song ◽  
Yu-Qin Qiu ◽  
Han-Chang Shi
Keyword(s):  
Oxygen Concentration ◽  
Concentration Profiles ◽  
Biokinetic Parameters

Pseudo-steady state oxygen-concentration profiles in an agar slab containing growing Nitrobacter agilis

1995 ◽  
Vol 79 (2) ◽  
pp. 167-170 ◽  
Author(s):  
RenéH. Wijffels ◽  
Meinard R. Eekhof ◽  
Drrk de Beer ◽  
Johannes C. van den Heuvel ◽  
Johannes Tramper
Keyword(s):  
Steady State ◽  
Oxygen Concentration ◽  
Concentration Profiles ◽  
Nitrobacter Agilis

Simulation of turbulence and dissolved oxygen concentration profiles over biofilm using k–ɛ turbulence model

2005 ◽  
Vol 52 (7) ◽  
pp. 181-186 ◽  
Author(s):  
H. Nagaoka ◽  
K. Sanda
Keyword(s):  
Mass Transfer ◽  
Dissolved Oxygen ◽  
Oxygen Concentration ◽  
Turbulence Model ◽  
Laser Doppler Velocimetry ◽  
Concentration Profiles ◽  
Doppler Velocimetry ◽  
Turbulent Model ◽  
Dissolved Oxygen Concentration ◽  
Oxygen Concentration Profile

The objective of this study is to investigate the flow structure over biofilm experimentally and theoretically. Velocity and turbulence profiles over biofilm measured by a laser Doppler velocimetry were compared to simulated profiles using the k–ɛ turbulent model. Also, dissolved oxygen concentration profiles over biofilm are measured using a micro DO sensor. The k–ɛ turbulence model was proved to be a useful tool for the understanding of mass transfer inside and outside biofilm. Dissolved oxygen concentration profile inside and outside biofilm showed the existence of turbulent diffusion inside biofilm.

Oxygen Distribution in Packed Bed Membrane Reactors For Partial Oxidation Systems and its Effect On Product Selectivity

2004 ◽  
Vol 2 (1) ◽  
Author(s):  
U. Kuerten ◽  
Martin van Sint Annaland ◽  
J.A.M. Kuipers
Keyword(s):  
Mass Transport ◽  
Oxygen Concentration ◽  
Partial Oxidation ◽  
Waste Product ◽  
Packed Bed ◽  
Product Formation ◽  
Convective Transport ◽  
Membrane Reactors ◽  
Concentration Profiles ◽  
Concentration Gradients

Packed bed membrane reactors (PBMRs) are currently considered for the distributive addition of oxygen in partial oxidation systems. Among other advantages the decreased oxygen concentrations in the PBMR can result in improved product selectivities for reaction systems in which the oxygen dependency of the target product formation is less pronounced than that of the waste product formation. Oxidative dehydrogenation (ODH) of methanol to formaldehyde (Diakov et al., 2002) and ethylbenzene to styrene (Shakhnovich et al., 1984) are industrially relevant examples of such a kinetic system.To achieve considerable selectivity improvements the oxygen concentration should be kept small compared to hydrocarbon concentrations. However, a decrease of the oxygen concentration is accompanied with a decrease in the effectiveness of the catalyst particles since the intraparticle oxygen concentration gradients (and not the hydrocarbon concentration gradients) predominantly determine the actual activity and product selectivities of the catalyst, rendering the common effectiveness factors inapplicable for the modeling of a PBMR.Furthermore, concentration profiles over the radius of the packed bed can emerge, if the radial mass transport rate of oxygen from the membrane wall to the center of the bed is insufficient compared to the local oxygen consumption rate. If the transmembrane flux is dominated by convective transport as typical with porous membranes, the radial oxygen concentration profiles result in increased product losses, and the use of a one-dimensional reactor model may result in an overestimation of the product selectivity.In this paper the effect of limitations of the oxygen mass transport in a PBMR – i.e. intraparticle and from the membrane to the centerline of the packed bed – have been discussed for the ODH of methanol and ethylbenzene.

Oxygen concentration profiles and exchange in sediment cores with circulated overlying water

1989 ◽  
Vol 21 (3) ◽  
pp. 401-409 ◽  
Author(s):  
JEAN-PIERRE R. A. SWEERTS ◽  
VINCE ST LOUIS ◽  
THOMAS E. CAPPENBERG
Keyword(s):  
Oxygen Concentration ◽  
Sediment Cores ◽  
Concentration Profiles ◽  
Overlying Water
Sign in / Sign up

Export Citation Format

Share Document