Browsing by Author "Brassington, Kirsty J."
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Item Open Access Effect of fertilizer formulation and bioaugmentation on biodegradation and leaching of crude oils and refined products in soils(Taylor & Francis, 2012-08-31T00:00:00Z) Coulon, Frederic; Brassington, Kirsty J.; Bazin, R.; Linnet, P. E.; Thomas, K. A.; Mitchell, T. R.; Lethbridge, Gordon; Smith, J. W. N.; Pollard, Simon J. T.The effects of soil characteristics and oil types as well as the efficacy of two fertilizer formulations and three bioaugmentation packages in improving the bioremediation of oil-contaminated soils were assessed as a means of ex situ treatment selection and optimization through seven laboratory microcosm studies. The influence of bioremediation on leaching of oil from the soil was also investigated. The studies demonstrated the benefits of biostimulation to overcome nutrient limitation, as most of the soils were nutrient depleted. The application of both liquid and pelleted slow-release N and P fertilizers increased both the hydrocarbon biodegradation rates (by a factor of 1.4 to 2.9) and the percentage of hydrocarbon mass degraded (by >30% after 12 weeks and 80% after 37 weeks), when compared with the unamended soils. Slow-release fertilizers can be particularly useful when multiple liquid applications are not practical or cost-effective. Bioaugmentation products containing inoculum plus fertilizer also increased biodegradation by 20% to 37% compared with unamended biotic controls; however, there was no clear evidence of additional benefits due to the inocula, compared with fertilizer alone. Therefore biostimulation is seen as the most cost-effective bioremediation strategy for contaminated soils with the levels of crude oil and refined products used in this study. However, site-specific considerations remain essential for establishing the treatability of oil-contaminated soils.Item Open Access Insights into the biodegradation of weathered hydrocarbons in contaminated soils by bioaugmentation and nutrient stimulation(Elsevier, 2016-07-18) Jiang, Ying; Brassington, Kirsty J.; Prpich, George; Paton, Graeme; Semple, Kirk T.; Pollard, Simon J. T.; Coulon, FredericThe potential for biotransformation of weathered hydrocarbon residues in soils collected from two commercial oil refinery sites (Soil A and B) was studied in microcosm experiments. Soil A has previously been subjected to on-site bioremediation and it was believed that no further degradation was possible while soil B has not been subjected to any treatment. A number of amendment strategies including bioaugmentation with hydrocarbon degrader, biostimulation with nutrients and soil grinding, were applied to the microcosms as putative biodegradation improvement strategies. The hydrocarbon concentrations in each amendment group were monitored throughout 112 days incubation. Microcosms treated with biostimulation (BS) and biostimulation/bioaugmentation (BS + BA) showed the most significant reductions in the aliphatic and aromatic hydrocarbon fractions. However, soil grinding was shown to reduce the effectiveness of a nutrient treatment on the extent of biotransformation by up to 25% and 20% for the aliphatic and aromatic hydrocarbon fractions, respectively. This is likely due to the disruption to the indigenous microbial community in the soil caused by grinding. Further, ecotoxicological responses (mustard seed germination and Microtox assays) showed that a reduction of total petroleum hydrocarbon (TPH) concentration in soil was not directly correlable to reduction in toxicity; thus monitoring TPH alone is not sufficient for assessing the environmental risk of a contaminated site after remediation.Item Open Access New insights into the biotransformation of weathered hydrocarbons in soil(Cranfield University, 2008-03) Brassington, Kirsty J.; Pollard, Simon; Coulon, FredericWeathered petroleum hydrocarbons are a highly complex, important soil contaminant. After forty years of petroleum research, weathered hydrocarbons are still not sufficiently understood or appropriately accounted for in contaminated land risk assessments or the associated analytical methods that inform them. Improved insights into these contaminants potential for biotransformation and their residual toxicity are essential for improving risk assessments, bioremediation strategies and effective regeneration of previously contaminated land. This thesis explores the biotransformation of weathered hydrocarbons in the context of risk assessment and management. The research includes a critical review and synthesis of six in-house historical pilot studies, implementation of a novel ultrasonic solvent extraction method for petroleum hydrocarbons and development of analytical tools, providing new insights for human and environmental risk assessments. The biotransformation potential and subsequent effect on the toxicity of two weathered hydrocarbon contaminated soils were investigated using soil microcosms. The use of a previously remediated soil provided novel insight into extended bioremediation potential for petroleum hydrocarbon residues to undergo further biotransformation. The novel ultrasonic extraction method developed collaboratively is a preferred alternative to traditional Soxhlet methods with very high precision (RSD ≤ 10%) and extraction efficiencies. Key benefits of the technique include reduced costs, shorter extraction times (1 h. vs. 8 h.) lower solvent consumption (40 ml vs. 150 ml) and improved extraction efficiencies (recovery ≥ 95 %). Ecotoxicological responses (using mustard seed germination and Microtox® assays) showed that a reduction in total petroleum hydrocarbon (TPH) load within soils could not necessarily be linked to a reduction in residual toxicity, thus reductions in TPH alone is not a suitable indicator of risk reduction. The residues in the previously remediated soil underwent further biotransformation with losses of up to 86 and 92 % in the aliphatic and aromatic fractions respectively. Grinding of this soil was shown to reduce the effectiveness of a nutrient treatment on the extent of biotransformation possible by up to 25% and 20% for the aliphatic and aromatic hydrocarbon fractions, respectively. Toxicity assays confirmed that biotransformation is not physically driven by surface area limitations, contrary to expectation, as responses of ground and un-ground soils were not significantly different (P>0.05). This may have implications for future studies using grinding as a pre-treatment, where biotransformation may be limited by grinding rather than other factors. Both the soils showed significant biotransformation (P<0.05) after 16 weeks of treatment. However, although the soil not previously treated had significantly less TPH losses, a loss of up to 92% shows that further degradation of this soil is possible even though previous investigations had suggested biotransformation had stopped. This has implications for bioremediation practitioners in that it questions whether bioremediation could be restarted and lower concentrations achieved, and warrants further investigation.Item Open Access Optimising the biopiling of weathered hydrocarbons within a risk management framework - PROMISE.(2005-04-01T00:00:00Z) Pollard, Simon J. T.; Hough, Rupert L.; Brassington, Kirsty J.; Sinke, Anja; Crossley, Jane; Paton, Graeme I.; Semple, Kirk T.; Risdon, Graeme C.; Jackman, Simon J.; Bone, B.; Jacobsen, Christian; Lethbridge, GordonThirty years of research into petroleum microbiology and bioremediation have bypassed an important observation – that many hydrocarbon contaminated sites posing potential risks to human health harbour weathered, ‘mid-distillate’ or heavy oils (Pollard, 2003). Ex-situ biopiling is an important technology for treating soils contaminated with weathered hydrocarbons. However, its performance continues to be represented by reference to reductions in the hydrocarbon ‘load’ in the soils being treated, rather than reductions in the risks posed by the hydrocarbon contamination (Owens and Bourgouin, 2003; Tien et al., 1999). The absence of ‘risk’ from the vocabulary of many operators and remediation projects reduces stakeholder (regulatory, investor, landowner, and public) confidence in remediation technologies, and subsequently limits the market potential of these technologies. Stakeholder confidence in the biopiling of weathered hydrocarbons may therefore be improved by demonstrating process optimisation within a validated risk management framework. To address these issues, a consortium led by Cranfield University’s Integrated Waste Management Centre has secured funding from the Government’s Bioremediation LINK programme. Project PROMISE (involving BP, SecondSite Regeneration Ltd., Dew Remediation Ltd., TES Bretby (Mowlem Group), technology translators PERA, and academics from Aberdeen, Cranfield and Lancaster Universities) aims to improve market confidence in biopiling by demonstrating how this treatment may be applied within a risk mItem Open Access Optimising the biopiling of weathered hydrocarbons within a risk management framework.(2005-10-01T00:00:00Z) Hough, Rupert L.; Brassington, Kirsty J.; Sinke, Anja; Crossley, Jane; Paton, Graeme I.; Semple, Kirk T.; Risdon, Graeme C.; Jacobsen, Christian; Daly, Paddy; Jackman, Simon J.; Lethbridge, Gordon; Pollard, Simon J. T.Thirty years of research into petroleum microbiology and bioremediation have bypassed an important observation – that many hydrocarbon contaminated sites posing potential risks to human health harbour weathered, ‘mid-distillate’ or heavy oils rather than ‘fresh product’ (Pollard, 2003). Ex-situ biopiling is an important technology for treating soils contaminated with weathered hydrocarbons. However, its performance continues to be represented by reference to reductions in the hydrocarbon ‘load’ in the soils being treated, rather than reductions in the risks posed by the hydrocarbon contamination (Owens and Bourgouin, 2003; Tien et al., 1999). The absence of ‘risk’ from the vocabulary of many operators and remediation projects reduces stakeholder (regulatory, investor, landowner, and public) confidence in remediation technologies, and subsequently limits the market potential of these technologies. Stakeholder confidence in the biopiling of weathered hydrocarbons may be improved by demonstrating process optimisation within a validated risk man