Influence of electric field strength on the microbial degradation of petroleum hydrocarbons

BACKGROUND Microbial remediation of petroleum-contaminated soil is a low-cost technology that does not produce secondary pollution. However, the microbial degradation cycle is often time consuming and inefficient on account of the strong hydrophobicity of petroleum hydrocarbons. RESULTS This study took contaminated soil around a well site in Xinjiang as the research object, isolated Bacillus from this soil to conduct experiments on the microbial degradation of petroleum hydrocarbons, and applied an external DC electric field to this system to enhance the microbial degradation rate. Results showed that a degradation rate of 69.1% within 9 days and soil dehydrogenase activity of 401 mg L-1 h(-1) could be achieved under an applied electric field intensity of 1.5 V cm(-1). Compared with the degradation effect without an electric field, the maximum degradation efficiency was improved to 73.1% in the presence of an electric field. The degradation kinetics obtained to fit the 3/2-order kinetic equation well, and the degradation half-life was 51-111 h. CONCLUSION Analysis of the petroleum degradation products revealed that the electric field enhances microbial degradation. Specifically, the electric field could not only accelerate the degradation of petroleum hydrocarbons by microorganisms but also change the products obtained after degradation. This study provides a research reference for the in situ remediation of petroleum hydrocarbon pollution. (c) 2021 Society of Chemical Industry

Automated summary

Microbial remediation of petroleum-contaminated soil is a low-cost and environmentally friendly technology. In this study, the use of an external DC electric field was found to significantly enhance the microbial degradation rate of petroleum hydrocarbons, leading to an improved degradation efficiency and faster degradation kinetics.