Organic Solvents Improve Hydrocarbon Desorption and Biodegradation in Highly Contaminated Weathered Soils

By Garcia-Rivero, M.; Saucedo-Castaneda, G. et al. | Journal of Environmental Engineering and Science, July 2007 | Go to article overview

Organic Solvents Improve Hydrocarbon Desorption and Biodegradation in Highly Contaminated Weathered Soils


Garcia-Rivero, M., Saucedo-Castaneda, G., Gutierrez-Rojas, M., Journal of Environmental Engineering and Science


Abstract: Slurry phase laboratory microcosms were used to investigate the effect of selected solvents (hexane, benzene, toluene, n-butanol, acetone, and methanol) on desorption and the resulting microbial biodegradation of hydrocarbons in highly contaminated weathered soils. For nonpolar solvents, solubility and desorption of hydrocarbons increased linearly as polarity increased. In desorption and biodegradation assays, toluene significantly increased hydrocarbon consumption by twice as much, in comparison to the control without solvent. After 30 culture days, the initial hydrocarbon concentration in soil (Soxhlet method), 237.2 g [kg.sup.-1] of dry soil, diminished 21% when toluene was initially added. Saturated and aromatic fractions became degraded to a greater extent in the presence of toluene, 11% and 50%, respectively. The results in this research indicated that the use of solvents is effective in improving both hydrocarbons desorption and biodegradation in highly polluted weathered soils.

Key words: slurry phase, overall hydrocarbon biodegradation, solvents, hydrocarbon fractions, biodegradation.

Resume : Des microcosmes de la phase de boue en laboratoire ont ete utilises pour examiner les effets de solvants selectionnes (hexane, benzene, toluene, n-butanol, acetone et methanol) sur la desorption et la biodegradation microbienne resultante d'hydrocarbures dans des sols alteres hautement contamines. Pour les solvants non polaires, la solubilite et la desorption des hydrocarbures augmentaient lineairement en fonction de l'augmentation de la polarite. Lors de tests de desorption/biodegradation, le toluene allait jusqu'a doubler la consommation d'hydrocarbures par rapport au controle sans solvant. Apres 30 jours de culture, la concentration initiale en hydrocarbures dans le sol (methode Soxhlet), 237,2 g [kg.sup.-1] de sol sec, avait diminue de 21 % lorsque du toluene avait ete ajoute au debut. Les fractions saturees et aromatiques se sont degradees plus fortement en presence de toluene, respectivement de 11 % et de 50 %. Les resultats de cette recherche indiquent que l'utilisation de solvants est efficace pour ameliorer la desorption et la biodegradation des hydrocarbures dans les sols alteres fortement pollues.

Mots-cles : phase de boue, biodegradation generale des hydrocarbures, solvants, fraction d'hydrocarbures, biodegradation.

[Traduit par la Redaction]

Introduction

Biological treatment of environmental pollutants offers economic and ecological alternatives to traditional physicochemical and thermal technologies. The major factor limiting the bioremediation of soils contaminated with hydrocarbons (HCs) is the poor availability of these hydrophobic compounds to microorganisms. Bioavailability is inversely correlated with compound sorption by soil, and sorption can protect a compound from microbial attack (Ainsworth et al. 1993).

Studies have shown that HC consumption occurs only in the liquid phase (Ghoshal et al. 1996) and that desorption rate controls the biodegradation rate (Carmichael et al. 1997). Given that mass transport is the limiting step in biodegradation, it must be improved by enhancing solubility in the liquid phase. One way of enhancing solubilization is adding surfactants or solvents. However, many difficulties are recognized regarding to the use of synthetic surfactants: they can prevent biodegradation because of their toxicity to microorganisms or due to the sequestration of compounds within micelles (Liu et al. 1995).

An alternative for improving the bioavailability of hydrophobic compounds is the use of solvents, which can increase the desorption rate from solid phase or even raise solubility in the liquid phase. For example, Jimenez and Bartha (1996) used different hydrophobic solvents, such as paraffin oil, in a two-liquid-phase bioreactor to increase biodegradation of pyrene. Bonten et al. (1999) studied the effects of short-term heating of contaminated soil, and soaking in an organic solvent on the subsequent biodegradation of polycyclic aromatic hydrocarbons (PAHs). …

The rest of this article is only available to active members of Questia

Already a member? Log in now.

Notes for this article

Add a new note
If you are trying to select text to create highlights or citations, remember that you must now click or tap on the first word, and then click or tap on the last word.
One moment ...
Default project is now your active project.
Project items
Notes
Cite this article

Cited article

Style
Citations are available only to our active members.
Buy instant access to cite pages or passages in MLA 8, MLA 7, APA and Chicago citation styles.

(Einhorn, 1992, p. 25)

(Einhorn 25)

(Einhorn 25)

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

Note: primary sources have slightly different requirements for citation. Please see these guidelines for more information.

Cited article

Organic Solvents Improve Hydrocarbon Desorption and Biodegradation in Highly Contaminated Weathered Soils
Settings

Settings

Typeface
Text size Smaller Larger Reset View mode
Search within

Search within this article

Look up

Look up a word

  • Dictionary
  • Thesaurus
Please submit a word or phrase above.
Print this page

Print this page

Why can't I print more than one page at a time?

Help
Full screen
Items saved from this article
  • Highlights & Notes
  • Citations
Some of your highlights are legacy items.

Highlights saved before July 30, 2012 will not be displayed on their respective source pages.

You can easily re-create the highlights by opening the book page or article, selecting the text, and clicking “Highlight.”

matching results for page

    Questia reader help

    How to highlight and cite specific passages

    1. Click or tap the first word you want to select.
    2. Click or tap the last word you want to select, and you’ll see everything in between get selected.
    3. You’ll then get a menu of options like creating a highlight or a citation from that passage of text.

    OK, got it!

    Cited passage

    Style
    Citations are available only to our active members.
    Buy instant access to cite pages or passages in MLA 8, MLA 7, APA and Chicago citation styles.

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn, 1992, p. 25).

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences."1

    1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

    Cited passage

    Thanks for trying Questia!

    Please continue trying out our research tools, but please note, full functionality is available only to our active members.

    Your work will be lost once you leave this Web page.

    Buy instant access to save your work.

    Already a member? Log in now.

    Search by... Author
    Show... All Results Primary Sources Peer-reviewed

    Oops!

    An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.