Browsing by Author "Daly, Paddy"

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    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
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    Understanding the fate and transport of petroleum hydrocarbons from coal tar within gasholders
    (Elsevier Science B.V., Amsterdam., 2009-02-28T00:00:00Z) Coulon, Frederic; Orsi, R.; Turner, Claire; Walton, Christopher; Daly, Paddy; Pollard, Simon J. T.
    Coal tars have been identified as posing a threat to human health due to their toxic, mutagenic and carcinogenic characteristics. Workers involved in former gasholders decommissioning are potentially exposed to relevant concentrations of volatile and semi-volatile hydrocarbons upon opening up derelict tanks and during tar excavation/removal. While information on contaminated sites air- quality and its implications on medium-long term exposure is available, acute exposure issues associated with the execution of critical tasks are less understood. Calculations indicated that the concentration of a given contaminant in the gasholder vapour phase only depends on the coal tar composition, being only barely affected by the presence of water in the gasholder and the tar volume/void space ratio. Fugacity modelling suggested that risk-critical compounds such as benzene, naphthalene and other monocyclic and polycyclic aromatic hydrocarbons may gather in the gasholder air phase at significant concentrations. Gasholder emissions were measured on-site and compared with the workplace exposure limits (WELs) currently in use in UK. While levels for most of the toxic compounds were far lower than WELs, benzene air-concentrations where found to be above the accepted threshold. In addition due to the long exposure periods involved in gasholder decommissioning and the significant contribution given by naphthalene to the total coal tar vapour concentration, the adoption of a WEL for naphthalene may need to be considered to support operators in preventing human health risk at the workplace. The Level I fugacity approach used in this study demonstrated its suitability for applications to sealed environments such as gasholders and its further refining could provide a useful tool for land remediation risk assessors. (C) 2008 Elsevier Ltd. All rights reserved.