Microbial community structure of a low sulfate oil producing facility indicate dominance of oil degrading/nitrate reducing bacteria and Methanogens

Analysis of microbial community structure of a low sulfate oil producing facility in Nigeria using 16S rRNA gene sequencing technique revealed dominance of oil degrading and nitrate reducing bacteria and methanogenic archaea in produced waters and oil samples namely, Marinobacter (37%), Azovibrio (21%), Thauera (10–28%), and Methanolobus (22%). On the contrary, the associated oil pipeline samples revealed massive dominance of potentially corrosive Methanolobus (60%) and Methanobacterium (25-27%). Further experimentation shows that the methanogens implicated in oil pipelines are corrosive moderate halophile that utilizes H2/CO2 and methanol as substrates. More emphasis should therefore be on methanogenic archaea as opposed to sulfate reducing bacteria (SRBs) during mitigation plans for microbially induced corrosion (MIC) in a low sulfate oil producing facilit

Induction of Souring and Corrosion by Anaerobic Microbial Activities in Offshore and Nearshore Oil-Producing Facilities in Nigeria

Anaerobic microbiological activities of two oil-producing facilities were determined by monitoring microbial activities in CSB-K medium and MPN counts of SRB in API RP-38 broth medium and APB in ZPRA-5 broth medium. Corrosion measurements were also carried out by weight loss method. Our investigation revealed that microbial activities at the near-shore facility were dominated by both sulfate reduction and methanogenesis with potential for souring and corrosion, while that of offshore was dominated by sulfate reduction, but the potential for souring and corrosion were reduced by frequent application of a combination of biocides by the operators

Biodegradation of Produce Water Hydrocarbons by Pure Cultures of Alcaligenes sp.

Biodegradation studies of hydrocarbons in untreated produce water from an oil production facility in Nigeria was undertaken over a period of time using pure cultures of Alkaligenes sp. Isolated from Escravos River where produce water was being discharged as at the time the studies were carried out. Gas chromatography and mass spectrometry were used to monitor the rate of reduction in some petroleum hydrocarbon fractions while the index used to evaluate biodegradation was the decreasing trend in the ratios of nC17/Pristane and nC18/Phytane. Gas chromatographic analysis showed that untreated produced water used for the study had an oil and grease content of 1407mg/L, this includes n-alkanes (608mg/L), Aromatics (13.88mg/L), NSO compounds (12.68mg/L) PAHs(0.833mg/L) and some unidentified greasy components. Upon mechanical treatment, the oil and grease component of produce water was reduced to 44mg/L comprising of n-alkanes (38.40mg/L), Aromatics (2.65mg/L), NSO compounds (1.78mg/L), PAHs (0.0655mg/L) and some unidentified greasy component. A pure culture of Alcaligenes sp. after 40 days of exposure to untreated produced water reduced the oil and grease content to 19.58mg/l comprising of n-Alkanes (16.87mg/l), Total aromatics (1.25mg/l), NSO compounds (0.98mg/l) and PAH (0.0096mg/l). This result indicate that produce water is readily biodegradable and pure cultures of Alcaligenes sp. used for the study were very efficient in the degradation of produced water hydrocarbons especially the recalcitrant PAH component when compared with the conventional mechanical treatment process. [Journal of American Science 2010;6(4):107-113]. (ISSN: 1545-1003)

Souring and Corrosion Potentials of Onshore and Offshore Oil-producing Facilities in the Nigerian Oil-rich Niger Delta

Souring and corrosion potentials of two oil producing facilities were determined by monitoring microbial activities in CSB-K medium and MPN counts of SRB and APB in API RP-38 and ZPRA-5 broth medium, respectively. Corrosion rate measurements were carried out by weight loss method. Our investigation revealed that microbiological activities at the onshore facility were dominated by methanogenesis with zero potential for souring and high potential for corrosion while that of offshore facility were dominated by sulfate reduction with high potential for both souring and corrosion. Biocide treatments were effective against the sulfate-reducing bacteria but not effective against the methanogens associated with corrosion

The effects of nitrogen and carbon sources on the ability of two microbial isolates to produce bioemulsifiers

Pseudomonas mallei and Pseudomonas pseudomallei were isolated from produced water samples collected from Escravos Tankfarm, Nigeria. The two bacterial isolates were found to produce very high emulsion turbidities when grown on hydrocarbon culture medium. The bioemulsifier produced by these two isolates were found to be related as they contain both protein and carbohydrate moieties of very close molecular weight and no trace of lipid. The bioemulsifier produced emulsified both aliphatic and aromatic hydrocarbons and also a variety of hydrocarbon mixtures such as olive oil, kerosene, diesel oil and crude oil. A combination of acetate and diesel oil seemed to be the preferred carbon source for bioemulsification while Ammonium sulfate was the preferred nitrogen source. Bioemulsifier production was highest at pH 7.05 while a pH greater than 7.25 inhibited bacterial growth and emulsifying activity

Plasmids of phenanthrene and dibenzothiophene-degrading bacteria isolated from produced water samples of oil production operations

Some bacterial isolates from produced water that showed extensive degradation of Polycyclic aromatic hydrocarbons (PAH) in produced water were screened for the presence of catabolic plasmids targeted for the degradation of phenanthrene and dibenzothiophene (DBT) to determine whether the genes responsible for the degradation of these substrates reside in either plasmid or chromosomal DNA. When grown on phenanthrene, Acinetobacter lwoffi, Enterobacter sp. And Pseudomonas sp. harbored some plasmids with molecular weights less than 23.1kbp except Pseudomonas sp that harbored plasmids with molecular weight higher than 48.5 kbp. When Corynebacterium sp., Vibrio sp. and Pseudomonas aeruginosa were grown on dibenzothiophene (DBT), Plasmids with molecular weights higher than 48.5kbp were found in these organisms. Upon further investigation and curing with acridine orange, the resident plasmids were lost in phenanthrene and DBT degrading isolates but all the organisms retained their abilities to grow on these compounds. This result indicates that the genes for the degradation of phenanthrene and DBT in these organisms probably reside in the Chromosomal DNA as opposed to the Plasmid DNA

The bio-corrosive nature of injection water sources used in the Nigerian oil and gas industry.

The bio-corrosive nature of injection water used in the Nigerian oil and gas industry from different sources such as seawater, produced water, brackish water, fresh and underground water were investigated with special emphasis on some of their components which enhance corrosion such as microbial activity, dissolved oxygen and presence of dissolved substances such as chlorides, sulfates and ammonia. Our investigation reveals that seawater, produced water and brackish water had higher salinity, conductivity, concentrations of dissolved oxygen, TDS, sulfate, organic nutrients, sulphate reducing bacteria (SRB), acid producing bacteria (APB) and higher corrosion rates (0.24-0.56 mm yr-1) than fresh and underground water whose corrosion rates ranged between 0.06-0.08 mm yr-1. Our study also established high correlation between corrosion rates and the concentrations of Fe2+, SRB, APB, TDS, DO and conductivity in all injection water samples examined in the study. The role of microorganisms in enhancing corrosion was also clearly established in some samples

Enhance Bioremediation of Hydrocarbon Contaminated Mangrove Swamp in the Nigerian Oil Rich Niger Delta Using Seawater, Microbial Inocula and Amended with Crude Oil Biosurfactants and Micronutrients

Abstract: Enhanced bioremediation of hydrocarbon contaminated mangrove swamp in the Nigerian oil rich Niger Delta was carried out using sea water microbial inocula amended with crude biosurfactants and micronutrients in a pilot scale experimental study that was monitored for 5 weeks. The indices used to monitor the progress of bioremediation were; the gradual loss in the gravimetric weight of oil, the biomarker index as exemplified by the decreasing trend in the ratios of nC17/Pristane and nC18/Phytane, the Gas chromatographic analysis of the residual oil and the population dynamics of hydrocarbon degrading bacteria. The bioremediation protocol employed in plot D where sea water microbial inocula was used in combination with crude biosurfactants and micronutrients was very efficient, fast and economical as after 7 days of application, about 97% of the total petroleum hydrocarbons (TPH) originally present in the contaminated mangrove swamp were removed. In plot C where sea water microbial inocula was applied along with micronutrients but without biosurfactants, the original TPH was reduced by 71% after 7 days of application. The other two plots (A and B) where neither sea water microbial inocula nor crude biosurfactants were applied showed no appreciable biodegradation after 14 days of application. Statistical analysis using analysis of variance (ANOVA) and Duncan multiple range test (DMRT) showed that seawater microbial inocula amended with crude biosurfactants and micronutrients significantly influenced bacterial growth and subsequent biodegradation of the petroleum hydrocarbon within a relatively short time. The short duration of the bioremediation program must have prevented the disastrous ecological consequences the prolonged presence of petroleum hydrocarbons would have caused the mangrove swamp environment. [Nature and Science 2010;8(8):195-206]. (ISSN: 1545-0740)

Biodegradation of produced water hydrocarbons by Aspergillus fumigatus

Abstract: Biodegradation studies of hydrocarbons in untreated produce water from an oil production facility in Nigeria was undertaken over a period of time using pure cultures of Alkaligenes sp. Isolated from Escravos River where produce water was being discharged as at the time the studies were carried out. Gas chromatography and mass spectrometry were used to monitor the rate of reduction in some petroleum hydrocarbon fractions while the index used to evaluate biodegradation was the decreasing trend in the ratios of nC17/Pristane and nC18/Phytane. Gas chromatographic analysis showed that untreated produced water used for the study had an oil and grease content of 1407mg/L, this includes n-alkanes (608mg/L), Aromatics (13.88mg/L), NSO compounds (12.68mg/L) PAHs(0.833mg/L) and some unidentified greasy components. Upon mechanical treatment, the oil and grease component of produce water was reduced to 44mg/L comprising of n-alkanes (38.40mg/L), Aromatics (2.65mg/L), NSO compounds (1.78mg/L), PAHs (0.0655mg/L) and some unidentified greasy component. A pure culture of Alcaligenes sp. after 40 days of exposure to untreated produced water reduced the oil and grease content to 19.58mg/l comprising of n-Alkanes (16.87mg/l), Total aromatics (1.25mg/l), NSO compounds (0.98mg/l) and PAH (0.0096mg/l). This result indicate that produce water is readily biodegradable and pure cultures of Alcaligenes sp. used for the study were very efficient in the degradation of produced water hydrocarbons especially the recalcitrant PAH component when compared with the conventional mechanical treatment process

Biodegradation of produced water hydrocarbons by Aspergillus fumigatus

Biodegradation studies of hydrocarbons in untreated produce water from an oil production facility in Nigeria were undertaken over a period of time using pure cultures of Aspergillus fumigatus isolated from the zone of produce water discharge into the receiving sea water. The rate of reduction in some petroleum hydrocarbon fractions such as n-Alkanes, Aromatics, Nitrogen Sulfur and Oxygen (NSO) containing compounds and Polycyclic aromatic hydrocarbons (PAHs) were monitored by means of Gas chromatography and Mass spectrometry using mechanically treated produced water as a reference. Gas chromatographic analysis showed that untreated produced water used in the study had an oil and grease content of 1407mg/l, this includes n-alkanes(608mg/l), Aromatics (13.88mg/l), NSO compounds (12.68mg/l) PAHs(0.833mg/l) and some unidentified greasy components. Upon mechanical treatment, the oil and grease component of produced water was reduced to 44mg/l comprising of nalkanes (38.40mg/), Aromatics (2.65mg/), NSO compounds(1.78mg/), PAHs (0.0655mg/) and some unidentified greasy component. A pure culture of Aspergillus fumigatus after 120 days of exposure to untreated produce water was able to reduce the hydrocarbons to the following components. n-Alkanes (78.5mg/l), Aromatics(1.58mg/l), NSO compounds (1.22mg/l) and PAHs (0.0168 mg/l). This result indicate that produce water from Chevron’s Escravos tank farm is readily biodegradable and the Aspergillus fumigatus culture used in the study was very effective in degrading the PAHs and NSO components of the hydrocarbon when compared with the conventional mechanical treatment process even though the biodegradation process was very slow