Volumetric Oxygen Mass Transfer Coefficient and Surface Tension in Simulated Salt Bioremediation Media

Abstract

Toluene can be removed from contaminated sites via bioremediation through the addition of biosurfactant compounds, which reduce the surface tension. However, aeration and mixing must be optimized to ensure an effective volumetric oxygen mass transfer coefficient (k L a). Experiments were perfomed with different salt containing solutions, which were tested either as such, or with different supplements. k L a values obtained at different agitation intensities and aeration rates were compared with those in water, and correlated with power number and superficial gas velocity. Surface tension decreased when surfactin was added to toluene-containing media. The seawater-simulating medium exhibited the highest surface tension reduction.

Kinetics of Hydroxyl Radical Production from Oxygenation of Reduced Iron Minerals and Their Reactivity with Trichloroethene: Effects of Iron Amounts, Iron Species, and Sulfate Reducing Bacteria

“…Literature values for k sol and k fre span large ranges that cover our best-fit parameters. Comparison of best-fit k sol and k fre indicates O 2 reacts more quickly with free compared to solid phase Fe­(II), in agreement with trends for O 2 reacting with aqueous Fe 2+ versus reduced nontronite reported by Zeng et al Literature values for k oe span a relatively small range (0.001 to 0.06 s –1 , Table S3), and the value depends on the degree of sample mixing. − Our value is relatively small because sample bottles were gently oscillated at 220 rpm on a shaker, while samples were rapidly mixed in prior work.…”

Probe dynamics influence on determination of volumetric oxygen transfer coefficient

“…The influence of the probe lag was also one of the research topic. However the probe lag impact is known and indicated as one that affect identification [6,19,20], there are not many publications that investigate this problem more precisely. The research on this topic usually concentrate on building the precise model of the probe and improving the determination of K L a [16,17,18,21], but usually presents the effect of probe lag on identification results using one or mostly two methods.…”

“…The influence of different factors such as temperature, pressure, stirrer rotation speed and microorganisms concentration on K L a identification results are widely discussed and investigated [6,8,9,10,11]. The influence of the probe lag was also one of the research topic.…”