Nitrogen as an indicator of mass transfer during in-situ gas sparging

2011 ◽  
Vol 126 (1-2) ◽  
pp. 8-18 ◽  
Author(s):  
Gerd U. Balcke ◽  
M. Hahn ◽  
Sascha E. Oswald
Keyword(s):  
Mass Transfer ◽  
Gas Sparging

The role of (bio)surfactant sorption in promoting the bioavailability of nutrients localized at the solid-water interface

1999 ◽  
Vol 39 (7) ◽  
pp. 91-98 ◽  
Author(s):  
Ryan N. Jordan ◽  
Eric P. Nichols ◽  
Alfred B. Cunningham
Keyword(s):  
Mass Transfer ◽  
Cell Membrane ◽  
Substrate Concentration ◽  
Water Interface ◽  
Industrial Systems ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Surfactant Sorption

Bioavailability is herein defined as the accessibility of a substrate by a microorganism. Further, bioavailability is governed by (1) the substrate concentration that the cell membrane “sees,” (i.e., the “directly bioavailable” pool) as well as (2) the rate of mass transfer from potentially bioavailable (e.g., nonaqueous) phases to the directly bioavailable (e.g., aqueous) phase. Mechanisms by which sorbed (bio)surfactants influence these two processes are discussed. We propose the hypothesis that the sorption of (bio)surfactants at the solid-liquid interface is partially responsible for the increased bioavailability of surface-bound nutrients, and offer this as a basis for suggesting the development of engineered in-situ bioremediation technologies that take advantage of low (bio)surfactant concentrations. In addition, other industrial systems where bioavailability phenomena should be considered are addressed.

An Optical Microreactor Enabling In Situ Spectroscopy Combined with Fast Gas-Liquid Mass Transfer

2018 ◽  
Vol 90 (11) ◽  
pp. 1855-1863 ◽  
Author(s):  
Sebastian Ponce ◽  
Hauke Christians ◽  
Alfons Drochner ◽  
Bastian J. M. Etzold
Keyword(s):  
Mass Transfer ◽  
In Situ Spectroscopy ◽  
Liquid Mass ◽  
Liquid Mass Transfer

Effect of gas sparging on the rate of mass transfer at a single sphere

1991 ◽  
Vol 47 (3) ◽  
pp. 187-191 ◽  
Author(s):  
M.A. Zarraa ◽  
Y.A. El-Tawil ◽  
H.A. Farag ◽  
M.Z. El-Abd ◽  
G.H. Sedahmed
Keyword(s):  
Mass Transfer ◽  
Gas Sparging ◽  
Single Sphere

Micro-environments and mass transfer phenomena in biofilms studied with microsensors

1999 ◽  
Vol 39 (7) ◽  
pp. 173-178 ◽  
Author(s):  
Dirk de Beer ◽  
Andreas Schramm
Keyword(s):  
Mass Transfer ◽  
Liquid Flow ◽  
Microbial Population ◽  
In Situ Hybridisation ◽  
Molecular Techniques ◽  
Complex Structures ◽  
Microbial Composition ◽  
Direct Observations ◽  
Direct Measurements

Direct observations on chemical micro-environment and microbial composition in biofilms are rare. The combination of microsensor and molecular techniques is highly useful for studies on the microbial ecology of biofilms. We shortly describe some applications of microsensors to study mass transfer phenomena and microbial processes in biofilms. It has recent been recognized that biofilms are not always flat layers of cells, but can consist of complex structures allowing liquid flow. Thus the classical view, that transport in biofilms is diffusional, is challenged. In laboratory grown biofilms the effect of convection on mass transfer was demonstrated. The microsensor technique has improved, so that direct in situ measurements in living biofilms are possible. By direct measurements of liquid flow with microsensors we show that in biofilms grown in bioreactors heterogeneity and convectional transport must also be taken into account. For the description of the microbial population we use molecular techniques, such as in situ hybridisation with 16S rRNA-targeted oligonucleotide probes. In a nitrifying-denitrifying biofilm we found a complex nitrifying community consisting of members of the genera Nitrosomonas, Nitrosospira, Nitrobacter and Nitrospira. Their occurrence was correlated with nitrification activity as determined by microsensor measurements.

In-situ sparging: Mass transfer mechanisms

1996 ◽  
Vol 6 (4) ◽  
pp. 15-29 ◽  
Author(s):  
Wilson S. Clayton ◽  
David H. Bass ◽  
Neil M. Ram ◽  
Christopher H. Nelson
Keyword(s):  
Mass Transfer ◽  
Transfer Mechanisms

In situ measurement of activity and mass transfer effects in enzyme immobilized electrodes

2006 ◽  
Vol 39 (1) ◽  
pp. 131-140 ◽  
Author(s):  
Wayne Johnston ◽  
Nathan Maynard ◽  
Bor Yann Liaw ◽  
Michael J. Cooney
Keyword(s):  
Mass Transfer ◽  
In Situ Measurement ◽  
Transfer Effects

In situ probing and evaluation of two different electrode materials in bio electrochemical systems by means of Optical Coherence Tomography on automated robotic platform

2020 ◽  
Author(s):  
Jinpeng Liu ◽  
Harald Horn ◽  
Michael Wagner
Keyword(s):  
Mass Transfer ◽  
Stainless Steel ◽  
Optical Coherence Tomography ◽  
Structural Parameters ◽  
Power Production ◽  
Fluid Structure Interactions ◽  
Biofilm Growth ◽  
Electrochemical Systems ◽  
Biofilm Structure

<p>Carbon-based and stainless steel-based materials are widely utilized as anode/cathode electrodes in bio electrochemical systems (BESs) due to its low capital cost, high conductivity and large specific surface area. Carbon-based materials such as carbon veil are mostly applied in lab-scale reactors because of its versatile shape and configuration. Moreover, stainless steel type materials show higher strength and are easier to incorporate within flow field. Optical coherence tomography (OCT) as an image technique is a suitable method to monitor biofilm growth and fluid-structure interactions at the meso-scale. In BESs, investigating bulk-biofilm interface (fluid-structure interactions) is of particular interest to optimize the mass transfer under suitable hydrodynamic condition and enhances the overall effectivity of BESs systems. To extend the knowledge about the influence of different anode electrodes as substratum on OCT monitoring and quantification, the biofilm structural properties analyzed by OCT image processing and bioelectrochemical systems performance were compared.  </p> <p>A custom-designed dual-chamber setup was constructed by two transparent optical flow cells and fixed in the automated monitoring platform (Evobot). Herein, we applied OCT to in-situ characterize and quantify the biofilm structure properties on two different anode electrodes (carbon veil-CV and porous stainless steel-SS) as substratum in microbial fuel cell (MFC) mode.  3D OCT dataset analysis presented 3 structural parameters for biofilm-carbon veil interface and 5 structural parameters for biofilm-stainless steel interface, separately. Biofilm volume (BioV) was calculated to compare CV and SS anode electrodes.</p> <p>In this study, a time-series of biofilm development was performed on both CV and SS materials. At the fourth day, the biofilm almost covered the entire anode surface and achieved 97% substratum coverage. Afterwards the biofilm grew mostly in vertical direction. With the further biofilm growth along height the electric resistance increased and power production gradually reached the equilibrium. Nevertheless, both materials did not show predominant advantage on power production. Furthermore, a relatively small error appeared on quantitative analysis of Biofilm volume using stainless steel. Whereas, the predictability of biofilm volume on the carbon veil anodes was hindered by the appearance of shadowing effects. Thus, it can be concluded that stainless steel flat plate electrode is preferable as anode material to investigate the interaction between biofilm structure, hydrodynamic conditions and mass transfer in BESs via OCT.</p>

Interferometry for in situ mass transfer measurements in a wind tunnel

1984 ◽  
Vol 2 (4) ◽  
pp. 203-203 ◽  
Author(s):  
B. L. Button ◽  
B. N. Dobbins
Keyword(s):  
Mass Transfer ◽  
Wind Tunnel
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