Electrolysis-driven bioremediation of crude oil-contaminated marine sediments

• Published in: New biotechnology Vol. 38; no. Pt B; pp. 84 - 90
• Main Authors: Bellagamba, Marco, Cruz Viggi, Carolina, Ademollo, Nicoletta, Rossetti, Simona, Aulenta, Federico
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 25.09.2017; Elsevier Science Ltd
• Subjects: Biodegradation; Biodegradation, Environmental; Bioremediation; Breaking down; Chemical analysis; Chlorine; Clean technology; Contaminants; Contaminated sediments; Contamination; Crude oil; Dimensionally stable anodes; Disasters; Electrode potentials; Electrolysis; Energy conservation; Energy requirements; Environmental conditions; Exploitation; Hydrocarbons; Marine pollution; Marine sediments; Marine technology; Microbial activity; Microorganisms; Oil pollution; Oil spills; Oxygen; Performance degradation; Petroleum hydrocarbons; Petroleum Pollution; Redox potential; Seawater; Seawater - chemistry; Seawater - microbiology; Sediment pollution; Sediments; Soil contamination; Soil management; Sulfate reduction; Water analysis; Water Pollutants - chemistry; Water Pollutants - metabolism; Water Pollution
• ISSN: 1871-6784; 1876-4347
• DOI: 10.1016/j.nbt.2016.03.003

•An electrochemical approach for oxygen delivery to contaminated marine sediments is presented.•A 2V voltage difference was applied continuously or intermittently across electrodes to drive seawater electrolysis.•Electrolysis allowed manipulating the redox potential of the sediment.•Electrolysis accelerated biodegradation of crude oil hydrocarbons while suppressing sulfate-reduction. Bioremediation is an effective technology to tackle crude oil spill disasters, which takes advantage of the capacity of naturally occurring microorganisms to degrade petroleum hydrocarbons under a range of environmental conditions. The enzymatic process of breaking down oil is usually more rapid in the presence of oxygen. However, in contaminated sediments, oxygen levels are typically too low to sustain the rapid and complete biodegradation of buried hydrocarbons. Here, we explored the possibility to electrochemically manipulate the redox potential of a crude oil-contaminated marine sediment in order to establish, in situ, conditions that are conducive to contaminants biodegradation by autochthonous microbial communities. The proposed approach is based on the exploitation of low-voltage (2V) seawater electrolysis to drive oxygen generation (while minimizing chlorine evolution) on Dimensionally Stable Anodes (DSA) placed within the contaminated sediment. Results, based on a laboratory scale setup with chronically polluted sediments spiked with crude oil, showed an increased redox potential and a decreased pH in the vicinity of the anode of ‘electrified’ treatments, consistent with the occurrence of oxygen generation. Accordingly, hydrocarbons biodegradation was substantially accelerated (up to 3-times) compared to ‘non-electrified’ controls, while sulfate reduction was severely inhibited. Intermittent application of electrolysis proved to be an effective strategy to minimize the energy requirements of the process, without adversely affecting degradation performance. Taken as a whole, this study suggests that electrolysis-driven bioremediation could be a sustainable technology for the management of contaminated sediments.