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Title: Assessment of intrinsic bioremediation of a coal-tar-affected aquifer using two-dimensional reactive transport and biogeochemical mass balance approaches

Abstract

Expedited site characterization and groundwater monitoring using direct-push technology and conventional monitoring wells were conducted at a former manufactured gas plant site. Biogeochemical data and heterotrophic plate counts support the presence of microbially mediated remediation. By superimposing solutions of a two-dimensional reactive transport analytical model, first-order degradation rate coefficients (day{sup -1}) of various compounds for the dissolved-phase plume were estimated (i.e., benzene (0.0084), naphthalene (0.0058), and acenaphthene (0.0011)). The total mass transformed by aerobic respiration, nitrate reduction, and sulfate reduction around the free-phase coal-tar dense-nonaqueous-phase-liquid region and in the plume was estimated to be approximately 4.5 kg/y using a biogeochemical mass-balance approach. The total mass transformed using the degradation rate coefficients was estimated to be approximately 3.6 kg/y. Results showed that a simple two-dimensional analytical model and a biochemical mass balance with geochemical data from expedited site characterization can be useful for rapid estimation of mass-transformation rates.

Authors:
; ; ; ;  [1]
  1. US EPA, Cincinnati, OH (United States). National Risk Management Research Laboratory
Publication Date:
OSTI Identifier:
20862322
Resource Type:
Journal Article
Resource Relation:
Journal Name: Water Environment Research; Journal Volume: 79; Journal Issue: 1
Country of Publication:
United States
Language:
English
Subject:
01 COAL, LIGNITE, AND PEAT; COAL TAR; AQUIFERS; REMEDIAL ACTION; COAL GASIFICATION PLANTS; ABANDONED SITES; TOWN GAS; BIODEGRADATION; BENZENE; NAPHTHALENE; PLUMES; GROUND WATER; GEOCHEMISTRY; POLYCYCLIC AROMATIC HYDROCARBONS; MASS BALANCE; TWO-DIMENSIONAL CALCULATIONS; BIOCHEMISTRY

Citation Formats

Rogers, S.W., Ong, S.K., Stenback, G.A., Golchin, J., and Kjartanson, B.H. Assessment of intrinsic bioremediation of a coal-tar-affected aquifer using two-dimensional reactive transport and biogeochemical mass balance approaches. United States: N. p., 2007. Web. doi:10.2175/106143006X123120.
Rogers, S.W., Ong, S.K., Stenback, G.A., Golchin, J., & Kjartanson, B.H. Assessment of intrinsic bioremediation of a coal-tar-affected aquifer using two-dimensional reactive transport and biogeochemical mass balance approaches. United States. doi:10.2175/106143006X123120.
Rogers, S.W., Ong, S.K., Stenback, G.A., Golchin, J., and Kjartanson, B.H. Mon . "Assessment of intrinsic bioremediation of a coal-tar-affected aquifer using two-dimensional reactive transport and biogeochemical mass balance approaches". United States. doi:10.2175/106143006X123120.
@article{osti_20862322,
title = {Assessment of intrinsic bioremediation of a coal-tar-affected aquifer using two-dimensional reactive transport and biogeochemical mass balance approaches},
author = {Rogers, S.W. and Ong, S.K. and Stenback, G.A. and Golchin, J. and Kjartanson, B.H.},
abstractNote = {Expedited site characterization and groundwater monitoring using direct-push technology and conventional monitoring wells were conducted at a former manufactured gas plant site. Biogeochemical data and heterotrophic plate counts support the presence of microbially mediated remediation. By superimposing solutions of a two-dimensional reactive transport analytical model, first-order degradation rate coefficients (day{sup -1}) of various compounds for the dissolved-phase plume were estimated (i.e., benzene (0.0084), naphthalene (0.0058), and acenaphthene (0.0011)). The total mass transformed by aerobic respiration, nitrate reduction, and sulfate reduction around the free-phase coal-tar dense-nonaqueous-phase-liquid region and in the plume was estimated to be approximately 4.5 kg/y using a biogeochemical mass-balance approach. The total mass transformed using the degradation rate coefficients was estimated to be approximately 3.6 kg/y. Results showed that a simple two-dimensional analytical model and a biochemical mass balance with geochemical data from expedited site characterization can be useful for rapid estimation of mass-transformation rates.},
doi = {10.2175/106143006X123120},
journal = {Water Environment Research},
number = 1,
volume = 79,
place = {United States},
year = {Mon Jan 15 00:00:00 EST 2007},
month = {Mon Jan 15 00:00:00 EST 2007}
}
  • Experiments at the Department of Energy’s Rifle Integrated Field Research Challenge (IFRC) site near Rifle, Colorado (USA) have demonstrated the ability to remove uranium from groundwater by stimulating the growth and activity of Geobacter species through acetate amendment. Prolonging the activity of these strains in order to optimize uranium bioremediation has prompted the development of minimally-invasive and spatially-extensive monitoring methods diagnostic of their in situ activity and the end products of their metabolism. Here we demonstrate the use of complex resistivity imaging for monitoring biogeochemical changes accompanying stimulation of indigenous aquifer microorganisms during and after a prolonged period (100+ days)more » of acetate injection. A thorough raw-data statistical analysis of discrepancies between normal and reciprocal measurements and incorporation of a new power-law phase-error model in the inversion were used to significantly improve the quality of the resistivity phase images over those obtained during previous monitoring experiments at the Rifle IRFC site. The imaging results reveal spatiotemporal changes in the phase response of aquifer sediments, which correlate with increases in Fe(II) and precipitation of metal sulfides (e.g., FeS) following the iterative stimulation of iron and sulfate reducing microorganism. Only modest changes in resistivity magnitude were observed over the monitoring period. The largest phase anomalies (>40 mrad) were observed hundreds of days after halting acetate injection, in conjunction with accumulation of Fe(II) in the presence of residual FeS minerals, reflecting preservation of geochemically reduced conditions in the aquifer – a prerequisite for ensuring the long-term stability of immobilized, redox-sensitive contaminants, such as uranium.« less
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