Document Detail


A partially coupled, fraction-by-fraction modelling approach to the subsurface migration of gasoline spills.
MedLine Citation:
PMID:  17014926     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The subsurface spreading behaviour of gasoline, as well as several other common soil- and groundwater pollutants (e.g. diesel, creosote), is complicated by the fact that it is a mixture of hundreds of different constituents, behaving differently with respect to e.g. dissolution, volatilisation, adsorption and biodegradation. Especially for scenarios where the non-aqueous phase liquid (NAPL) phase is highly mobile, such as for sudden spills in connection with accidents, it is necessary to simultaneously analyse the migration of the NAPL and its individual components in order to assess risks and environmental impacts. Although a few fully coupled, multi-phase, multi-constituent models exist, such models are highly complex and may be time consuming to use. A new, somewhat simplified methodology for modelling the subsurface migration of gasoline while taking its multi-constituent nature into account is therefore introduced here. Constituents with similar properties are grouped together into eight fractions. The migration of each fraction in the aqueous and gaseous phases as well as adsorption is modelled separately using a single-constituent multi-phase flow model, while the movement of the free-phase gasoline is essentially the same for all fractions. The modelling is done stepwise to allow updating of the free-phase gasoline composition at certain time intervals. The output is the concentration of the eight different fractions in the aqueous, gaseous, free gasoline and solid phases with time. The approach is evaluated by comparing it to a fully coupled multi-phase, multi-constituent numerical simulator in the modelling of a typical accident-type spill scenario, based on a tanker accident in northern Sweden. Here the PCFF method produces results similar to those of the more sophisticated, fully coupled model. The benefit of the method is that it is easy to use and can be applied to any single-constituent multi-phase numerical simulator, which in turn may have different strengths in incorporating various processes. The results demonstrate that the different fractions have significantly different migration behaviours and although the methodology involves some simplifications, it is a considerable improvement compared to modelling the gasoline constituents completely individually or as one single mixture.
Authors:
F Fagerlund; A Niemi
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Publication Detail:
Type:  Comparative Study; Evaluation Studies; Journal Article; Research Support, Non-U.S. Gov't     Date:  2006-10-02
Journal Detail:
Title:  Journal of contaminant hydrology     Volume:  89     ISSN:  0169-7722     ISO Abbreviation:  J. Contam. Hydrol.     Publication Date:  2007 Jan 
Date Detail:
Created Date:  2006-12-05     Completed Date:  2007-03-19     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8805644     Medline TA:  J Contam Hydrol     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  174-98     Citation Subset:  IM    
Affiliation:
Department of Earth Sciences, Hydrology, Uppsala University, Villavägen 16, 75236 Uppsala, Sweden. Fritjof.Fagerlund@hyd.uu.se
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MeSH Terms
Descriptor/Qualifier:
Computer Simulation
Gases / analysis
Gasoline / analysis*
Models, Theoretical*
Soil Pollutants / analysis
Water Movements*
Water Pollutants, Chemical / analysis
Chemical
Reg. No./Substance:
0/Gases; 0/Gasoline; 0/Soil Pollutants; 0/Water Pollutants, Chemical

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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