Petroleum Research Today is a free monthly online journal that collates and summarizes the latest research about Petroleum, including details on crude oil, extraction, chemistry, pollution. | ||||||||
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Effect of salt on aerobic biodegradation of petroleum hydrocarbons in contaminated groundwater.Ulrich AC, Guigard SE, Foght JM, Semple KM, Pooley K, Armstrong JE, Biggar KW Department of Civil and Environmental Engineering, University of Alberta, Edmonton, AB, Canada, T6G 2W2, aulrich@ualberta.ca. Hydrocarbon-contaminated soil and groundwater at oil and gas production sites may be additionally impacted by salts due to release of produced waters. However, little is known about the effect of salt on the in-situ biodegradation of hydrocarbons by terrestrial microbes, especially at low temperatures. To study this effect, we prepared a groundwater-soil slurry from two sites in Canada: a former flare pit site contaminated with flare pit residue (Site A), and a natural gas processing facility contaminated with natural gas condensate (Site B). The slurry with its indigenous microbes was amended with radiolabeled hydrocarbons dissolved in free product plus nutrients and/or NaCl, and incubated in aerobic biometer flasks with gyrotory shaking at either 25 or 10 degrees C for up to 5 weeks. Cumulative production of (14)CO(2) was measured and the lag time, rate and extent of mineralization were calculated. For Site A, concentrations of NaCl >/=1% (w/v) delayed the onset of mineralization of both (14)C-hexadecane and (14)C-phenanthrene under nutrient-amended conditions, but once biodegradation began the degradation rates were similar over the range of salt concentrations tested (0-5% NaCl). For Site B, increasing concentrations of NaCl >/=1% (w/v) increased the lag time and decreased the rate and extent of mineralization of aliphatic and aromatic substrates. Of particular interest is the observation that low concentrations of salt (</=1% NaCl) slightly stimulated mineralization in some cases. Published 25 April 2008 in Biodegradation.
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