Browsing by Author "Okoro, C. C."
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Item Biodegradation of Hydrocarbons in Untreated Produced Water using Pure and Mixed Microbial Cultures(2002) Okoro, C. C.; Amund, Olukayode O.Biodegradation studies of hydrocarbons in untreated produced water from Escravos tank farm were undertaken over a period of time using Pure and Mixed microbial cultures and the produced water as the sole carbon and energy source. Gas chromatographic analysis showed that untreated produced water with an oil and grease content of 1407 mg/1 contained various petroleum hydrocarbon fractions including n-alkanes (608mg/1), NSO compounds (12.68mg/1) and PAHs (0.833mg/l). Upon mechanical treatment, the oil and grease content of produced water was reduced to 44mg/l while n-alkanes, aromatics, NSO compounds and PAHs were reduced to 38.4, 2.65, 1.78, 0.0655 mg/l respectively. An Achromobacter sp., used in pure culture and without nutrient supplementation reduced the oil and grease content to 18 mg/l while n-alkanes, aromatics, NSO compounds and PAHs were reduced to 13.68, 1.32, 1.20, and 0.0056 mg/l respectively after 40 days of exposure and this result was better than when mixed microbial culture were used. This is an indication that produced water hydrocarbons are readily biodegradable and pure bacterial cultures can be very effective in degrading its petroleum hydrocarbons.Item Biologically Active Solid Deposits in Biocide treated Oil and Gas pipelines from a Nigerian Onshore Oil Production Facility(National Institute of Ecology, 2013) Okoro, C. C.; Amund, Olukayode O.; Samuel, O. B.Pipelines transporting crude oil, produced water and gas from an onshore oil producing facility in Nigeria are subject to frequent corrosion failures despite treatment programs with chlorine (0.5mg L-1) and sodium azide (0.2 mg L-1). Solid deposit samples from 6 corroded pipelines were analyzed chemically and biologically to determine whether the corrosion episodes were as a result of microbial activity. Microbiological analysis showed relatively high concentrations of microorganisms associated with corrosion such as SRBs (103-105 cell g-1) and APBs (103-107 cells g-1) while chemical analysis showed evidence of corrosion products such as iron II, calcium, sulfide, carbonate and bicarbonate. Chemical analysis also revealed that environmental conditions such as availability of nutrients, pH, moisture and redox potential were favorable for the growth and proliferation of these microorganisms. All the pipeline samples that were investigated recorded remarkable corrosion rates that ranged from 0.065-0.30 mm yr-1 but the rates were higher in chloride treated pipelines. Our investigation revealed that the solid deposit samples were biologically active and pipeline corrosion was as a result of microbial activity. Thus the prevalence of bio-corrosion is likely to be higher in cases where routine pipeline cleaning and checks are not strictly adhered to despite regular biocide treatment programs