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

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. [Journal of American Science 2010;6(4):107-113]. (ISSN: 1545-1003).