The use of 2D non-uniform electric field to enhance in situ bioremediation of 2,4-dichlorophenol-contaminated soil.

In situ bioremediation is a safe and cost-effective technology for the cleanup of organic-contaminated soil, but its remediation rate is usually very slow, which results primarily from limited mass transfer of pollutants to the degrading bacteria in soil media. This study investigated the feasibility of adopting 2D non-uniform electric field to enhance in situ bioremediation process by promoting the mass transfer of organics to degrading bacteria under in situ conditions. For this purpose, a 2D non-uniform electrokinetic system was designed and tested at bench-scale with a sandy loam as the model soil and 2,4-dichlorophenol (2,4-DCP) as the model organic pollutant at two common operation modes (bidirectional and rotational). Periodically, the electric field reverses its direction at bidirectional mode and revolves a given angle at rotational mode. The results demonstrated that the non-uniform electric field could effectively stimulate the desorption and the movement of 2,4-DCP in the soil. The 2,4-DCP was mobilized through soil media towards the anode at a rate of about 1.0 cmd(-1)V(-1). The results also showed that in situ biodegradation of 2,4-DCP in the soil was greatly enhanced by the applied 2D electric field upon operational mode. At the bidirectional mode, an average 2,4-DCP removal of 73.4% was achieved in 15 days, and the in situ biodegradation of 2,4-DCP was increased by about three times as compared with that uncoupled with electric field, whereas, 34.8% of 2,4-DCP was removed on average in the same time period at the rotational mode. In terms of maintaining remediation uniformity in soil, the rotational operation remarkably excelled the bidirectional operation. In the hexagonal treatment area, the 2,4-DCP removal efficiency adversely increase with the distance to the central electrode at the bidirectional mode, while the rotational mode generated almost uniform removal in soil bed.

[1]  Shunitz Tanaka,et al.  Electrokinetic remediation of clayey soils containing copper(II)-oxinate using humic acid as a surfactant. , 2003, Journal of hazardous materials.

[2]  G. C. Yang,et al.  Remediation of TCE contaminated soils by in situ EK-Fenton process. , 2001, Journal of hazardous materials.

[3]  A. Zehnder,et al.  Mass transfer limitation of biotransformation: quantifying bioavailability , 1997 .

[4]  L. Cavalca,et al.  Degradation of 2,4,6‐trichlorophenol by a specialized organism and by indigenous soil microflora: bioaugmentation and self‐remediability for soil restoration , 1998, Letters in applied microbiology.

[5]  Philip H. Brodsky,et al.  Integrated in situ soil remediation technology: the lasagna process. , 1995, Environmental science & technology.

[6]  P. Armenante,et al.  Aerobic degradation and dechlorination of 2–chlorophenol, 3‐chlorophenol and 4‐chlorophenol by a Pseudomonas pickettii strain , 1995, Letters in applied microbiology.

[7]  Hui Wang,et al.  The use of non-uniform electrokinetics to enhance in situ bioremediation of phenol-contaminated soil. , 2005, Journal of hazardous materials.

[8]  Petri Latostenmaa,et al.  Electrokinetic soil remediation--critical overview. , 2002, The Science of the total environment.

[9]  Sunggyu Lee,et al.  Effect of oxygen amendments and soil pH on bioremediation of industrially contaminated soils , 1996 .

[10]  L. Cavalca,et al.  Chlorophenol removal from soil suspensions: Effects of a specialised microbial inoculum and a degradable analogue , 2004, Biodegradation.

[11]  Si-Jing Wang,et al.  Biotransformation kinetics of Pseudomonas putida for cometabolism of phenol and 4-chlorophenol in the presence of sodium glutamate , 2004, Biodegradation.

[12]  R. Sims,et al.  Bioremediation of Contaminated Soils , 1999 .

[13]  E. Voudrias,et al.  Sorption-desorption behaviour of 2,4-dichlorophenol by marine sediments. , 2000, Chemosphere.

[14]  M. Bayer,et al.  The electrophoretic mobility of gram-negative and gram-positive bacteria: an electrokinetic analysis. , 1990, Journal of general microbiology.

[15]  Qi-shi Luo,et al.  In situ bioelectrokinetic remediation of phenol-contaminated soil by use of an electrode matrix and a rotational operation mode. , 2006, Chemosphere.

[16]  Qi-shi Luo,et al.  Mobilization of phenol and dichlorophenol in unsaturated soils by non-uniform electrokinetics. , 2005, Chemosphere.

[17]  R. Céspedes,et al.  Degradation of Chlorophenols by Alcaligenes eutrophus JMP134(pJP4) in Bleached Kraft Mill Effluent , 1997, Applied and environmental microbiology.

[18]  R. J. Gale,et al.  Optimization of 2-D Electrode Configuration for Electrokinetic Remediation , 1999 .

[19]  X. Quan,et al.  Biodegradation of 2,4-dichlorophenol in sequencing batch reactors augmented with immobilized mixed culture. , 2003, Chemosphere.

[20]  C. Knowles,et al.  Electrokinetic remediation of metals and organics from historically contaminated soil , 2000 .

[21]  W. B. Betts,et al.  The potential of dielectrophoresis for the real-time detection of microorganisms in foods , 1995 .

[22]  J. Puhakka,et al.  Aerobic fluidized-bed treatment of polychlorinated phenolic wood preservative constituents , 1992 .

[23]  C. L. Page,et al.  Electroremediation of Contaminated Soils , 2002 .