Limits...
The "Oil-Spill Snorkel": an innovative bioelectrochemical approach to accelerate hydrocarbons biodegradation in marine sediments.

Cruz Viggi C, Presta E, Bellagamba M, Kaciulis S, Balijepalli SK, Zanaroli G, Petrangeli Papini M, Rossetti S, Aulenta F - Front Microbiol (2015)

Bottom Line: Electrons flow through the snorkel up to the part exposed to the aerobic environment (the cathode), where they reduce oxygen to form water.Collectively, the results of this study confirmed that the snorkels accelerate oxidative reactions taking place within the sediment, as documented by a significant 1.7-fold increase (p = 0.023, two-tailed t-test) in the cumulative oxygen uptake and 1.4-fold increase (p = 0.040) in the cumulative CO2 evolution in the microcosms containing three snorkels compared to snorkel-free controls.Indeed, while after 200 days of incubation a negligible degradation of TPH was noticed in snorkel-free controls, a significant reduction of 12 ± 1% (p = 0.004) and 21 ± 1% (p = 0.001) was observed in microcosms containing one and three snorkels, respectively.

View Article: PubMed Central - PubMed

Affiliation: Water Research Institute, National Research Council Rome, Italy.

ABSTRACT
This study presents the proof-of-concept of the "Oil-Spill Snorkel": a novel bioelectrochemical approach to stimulate the oxidative biodegradation of petroleum hydrocarbons in sediments. The "Oil-Spill Snorkel" consists of a single conductive material (the snorkel) positioned suitably to create an electrochemical connection between the anoxic zone (the contaminated sediment) and the oxic zone (the overlying O2-containing water). The segment of the electrode buried within the sediment plays a role of anode, accepting electrons deriving from the oxidation of contaminants. Electrons flow through the snorkel up to the part exposed to the aerobic environment (the cathode), where they reduce oxygen to form water. Here we report the results of lab-scale microcosms setup with marine sediments and spiked with crude oil. Microcosms containing one or three graphite snorkels and controls (snorkel-free and autoclaved) were monitored for over 400 days. Collectively, the results of this study confirmed that the snorkels accelerate oxidative reactions taking place within the sediment, as documented by a significant 1.7-fold increase (p = 0.023, two-tailed t-test) in the cumulative oxygen uptake and 1.4-fold increase (p = 0.040) in the cumulative CO2 evolution in the microcosms containing three snorkels compared to snorkel-free controls. Accordingly, the initial rate of total petroleum hydrocarbons (TPH) degradation was also substantially enhanced. Indeed, while after 200 days of incubation a negligible degradation of TPH was noticed in snorkel-free controls, a significant reduction of 12 ± 1% (p = 0.004) and 21 ± 1% (p = 0.001) was observed in microcosms containing one and three snorkels, respectively. Although, the "Oil-Spill Snorkel" potentially represents a groundbreaking alternative to more expensive remediation options, further research efforts are needed to clarify factors and conditions affecting the snorkel-driven biodegradation processes and to identify suitable configurations for field applications.

No MeSH data available.


Related in: MedlinePlus

(A) Amount of total cells and Bacteria in the sediment from the different treatments as measured after 0, 200, and 417 days of incubation. (B) Analysis of the bacterial component of the microbial community of the sediment using group-specific Catalyzed Reporter Deposition-Fluorescence In Situ Hybridization (CARD-FISH) probes (samples taken at the end of the incubation). Error bars represent the SE of replicate samples.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4559663&req=5

Figure 5: (A) Amount of total cells and Bacteria in the sediment from the different treatments as measured after 0, 200, and 417 days of incubation. (B) Analysis of the bacterial component of the microbial community of the sediment using group-specific Catalyzed Reporter Deposition-Fluorescence In Situ Hybridization (CARD-FISH) probes (samples taken at the end of the incubation). Error bars represent the SE of replicate samples.

Mentions: A whole-cell detection method was applied for the characterization of the microbial communities growing in the sediment and at the surface of the graphite rods (i.e., “the snorkels”) in the different microcosms. As shown in Figure 5A, near the totality of the microbial population in the sediment was composed of Bacteria, with a ratio Bacteria/total DAPI stained cells ranging between 83 and 99%. The abundance of total microbial cells and Bacteria in the sediment samples from the live control (treatment “C”) and from the microcosms containing the “snorkel(s)” (treatment “S” and “S3”) increased over time, ultimately reaching a similar value of around 5 × 107 cells per gram of sediment at the end of the incubation (i.e., day 417; Figure 5A). A statistically relevant difference among the treatments was observed on day 200 whereby the concentration of total cells in the microcosms containing the snorkel(s) was higher than in the corresponding control (4.4 ± 0.4 × 107 and 4.5 ± 0.4 × 107 cells per gram of sediment in treatment “S” and “S3,” respectively, versus 3.1 ± 0.3 × 107 cells per gram of sediment in treatment “C”; p < 0.001 for both “S” and “S3” treatments, two-tailed t-test; Figure 5A).


The "Oil-Spill Snorkel": an innovative bioelectrochemical approach to accelerate hydrocarbons biodegradation in marine sediments.

Cruz Viggi C, Presta E, Bellagamba M, Kaciulis S, Balijepalli SK, Zanaroli G, Petrangeli Papini M, Rossetti S, Aulenta F - Front Microbiol (2015)

(A) Amount of total cells and Bacteria in the sediment from the different treatments as measured after 0, 200, and 417 days of incubation. (B) Analysis of the bacterial component of the microbial community of the sediment using group-specific Catalyzed Reporter Deposition-Fluorescence In Situ Hybridization (CARD-FISH) probes (samples taken at the end of the incubation). Error bars represent the SE of replicate samples.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4559663&req=5

Figure 5: (A) Amount of total cells and Bacteria in the sediment from the different treatments as measured after 0, 200, and 417 days of incubation. (B) Analysis of the bacterial component of the microbial community of the sediment using group-specific Catalyzed Reporter Deposition-Fluorescence In Situ Hybridization (CARD-FISH) probes (samples taken at the end of the incubation). Error bars represent the SE of replicate samples.
Mentions: A whole-cell detection method was applied for the characterization of the microbial communities growing in the sediment and at the surface of the graphite rods (i.e., “the snorkels”) in the different microcosms. As shown in Figure 5A, near the totality of the microbial population in the sediment was composed of Bacteria, with a ratio Bacteria/total DAPI stained cells ranging between 83 and 99%. The abundance of total microbial cells and Bacteria in the sediment samples from the live control (treatment “C”) and from the microcosms containing the “snorkel(s)” (treatment “S” and “S3”) increased over time, ultimately reaching a similar value of around 5 × 107 cells per gram of sediment at the end of the incubation (i.e., day 417; Figure 5A). A statistically relevant difference among the treatments was observed on day 200 whereby the concentration of total cells in the microcosms containing the snorkel(s) was higher than in the corresponding control (4.4 ± 0.4 × 107 and 4.5 ± 0.4 × 107 cells per gram of sediment in treatment “S” and “S3,” respectively, versus 3.1 ± 0.3 × 107 cells per gram of sediment in treatment “C”; p < 0.001 for both “S” and “S3” treatments, two-tailed t-test; Figure 5A).

Bottom Line: Electrons flow through the snorkel up to the part exposed to the aerobic environment (the cathode), where they reduce oxygen to form water.Collectively, the results of this study confirmed that the snorkels accelerate oxidative reactions taking place within the sediment, as documented by a significant 1.7-fold increase (p = 0.023, two-tailed t-test) in the cumulative oxygen uptake and 1.4-fold increase (p = 0.040) in the cumulative CO2 evolution in the microcosms containing three snorkels compared to snorkel-free controls.Indeed, while after 200 days of incubation a negligible degradation of TPH was noticed in snorkel-free controls, a significant reduction of 12 ± 1% (p = 0.004) and 21 ± 1% (p = 0.001) was observed in microcosms containing one and three snorkels, respectively.

View Article: PubMed Central - PubMed

Affiliation: Water Research Institute, National Research Council Rome, Italy.

ABSTRACT
This study presents the proof-of-concept of the "Oil-Spill Snorkel": a novel bioelectrochemical approach to stimulate the oxidative biodegradation of petroleum hydrocarbons in sediments. The "Oil-Spill Snorkel" consists of a single conductive material (the snorkel) positioned suitably to create an electrochemical connection between the anoxic zone (the contaminated sediment) and the oxic zone (the overlying O2-containing water). The segment of the electrode buried within the sediment plays a role of anode, accepting electrons deriving from the oxidation of contaminants. Electrons flow through the snorkel up to the part exposed to the aerobic environment (the cathode), where they reduce oxygen to form water. Here we report the results of lab-scale microcosms setup with marine sediments and spiked with crude oil. Microcosms containing one or three graphite snorkels and controls (snorkel-free and autoclaved) were monitored for over 400 days. Collectively, the results of this study confirmed that the snorkels accelerate oxidative reactions taking place within the sediment, as documented by a significant 1.7-fold increase (p = 0.023, two-tailed t-test) in the cumulative oxygen uptake and 1.4-fold increase (p = 0.040) in the cumulative CO2 evolution in the microcosms containing three snorkels compared to snorkel-free controls. Accordingly, the initial rate of total petroleum hydrocarbons (TPH) degradation was also substantially enhanced. Indeed, while after 200 days of incubation a negligible degradation of TPH was noticed in snorkel-free controls, a significant reduction of 12 ± 1% (p = 0.004) and 21 ± 1% (p = 0.001) was observed in microcosms containing one and three snorkels, respectively. Although, the "Oil-Spill Snorkel" potentially represents a groundbreaking alternative to more expensive remediation options, further research efforts are needed to clarify factors and conditions affecting the snorkel-driven biodegradation processes and to identify suitable configurations for field applications.

No MeSH data available.


Related in: MedlinePlus