Effect of salt on aerobic biodegradation of petrol

Authors: Ania C Ulrich Selma E Guigard Julia M Foght Kathleen M Semple Kathryn Pooley James E Armstrong Kevin W Biggar

Publish Date: 2008/04/25

Volume: 20, Issue: 1, Pages: 27-38

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Abstract

Hydrocarboncontaminated 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 insitu biodegradation of hydrocarbons by terrestrial microbes especially at low temperatures To study this effect we prepared a groundwatersoil 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°C for up to 5 weeks Cumulative production of 14CO2 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 14Chexadecane and 14Cphenanthrene under nutrientamended 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 casesThis project was funded by the Water Research Users Group Alberta Environment and was part of the Consortium for Research on Natural Attenuation CORONA funded by the NSERC Collaborative Research and Development CRD program Summer student funding to KP was received from the NSERC USRA program Inkind support by Devon Canada Ltd ConocoPhillips Canada Ltd WorleyParsons Komex International Ltd and Maxxam Analytics is gratefully acknowledged

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