Effect of polarity‐reversal and electrical intensity on the oil removal from soil

Abstract

BACKGROUND: Although electro-bioremediation (EK-Bio) is effective at removing organic contaminants from soil, the role of electrical intensity (EI) and polarity-reversal (PR) remains unclear. Two electrokinetic reactors (ER I and II) with six treatments (EK-I, EK-PR-I, Bio-I, EK-Bio-I, EK-Bio-PR-I and EK-PR-II) were applied for 42 days to examine the effect of EI and PR on oil EK-Bio remediation. RESULTS: The final oil degradation rate in EK-Bio-PR-I was 27.8%, representing an increase of 18.4%, 11.3% and 7.6% compared with EK-I, Bio-I and EK-Bio-I, respectively. Soil pH remained at around 6.6, and the average bacterial counts increased from 7.66 to 8.41 log 10 cfu g -1 dry soil by the end of EK-Bio-PR-I. There was a significant positive linear correlation between EI and the oil degradation rate in EK-I (y = 0.6919x + 9.2278; Pearson correlation coefficient = 0.9887). The simulated oil degradation rate was assessed according to the above equation in an amplification experiment (EK-PR-II), and the observed oil degradation rate showed no significant difference with the simulated data (P > 0.05).CONCLUSION: EI and PR have positive effects on oil degradation efficiency and soil bacteria, indicating that EK-Bio with appropriate EI and periodic PR is the best approach for removing oil from soil.

Compositional and metabolic quotient analysis of heavy metal contaminated soil after electroremediation

“…Rigorous study of individual tests with a variety of enzyme and microbial activity outcomes evaluated the soil quality after EKR (Muscolo et al 2014;Wang et al 2009). Notwithstanding this report, Li et al (2015) made an effort to combine EK process and bioremediation (EK-bioremediation) to enhance the transport of bacteria or nutrients for effective biodegradation. They observed that electrical intensity has positive effects on oil degradation efficiency and soil bacteria, indicated that EK-Bio with appropriate electrical intensity is a suitable approach for removing organic contaminants from soil.…”

Effect of polarity-reversal on electrokinetic enhanced bioremediation of Pyrene contaminated soil

“…To overcome the drawback, a series of methods were used to control the pH, such as injecting solution [11][12][13], fixing the cathode and approaching anodes [14,15], electrolyte circulation [16,17] and non-uniform electrokinetics [5,18]. Polarity reversal was proposed for neutralizing soil pH and stimulating bioremediation of organic contaminated soil [4,9,19]. Bioremediation coupled with EK-PR could increase the temperature, bioavailability and transformation of organic contaminants without causing extreme pH conditions at the electrodes [20,21].…”

“…In addition, this technique may enhance the microbial activity for the degradation of contaminants, by producing oxygen at the anode [22]. In EK-Bio technology, the removal of organic contaminant likely depends not only on the effect of biodegradation, but also on that of electrical intensity induced stimulation [19].…”

Integrating Electrokinetic and Bioremediation Process for Treating Oil Contaminated Low Permeability Soil

“…However, a larger TPH removal is likely to occur when prolonging the research process. Development carried out in this research can be an option in supporting the effectiveness of electrokinetic bioremediation process [16], [17].…”