TY - JOUR
T1 - ZVI-Clay remediation of a chlorinated solvent source zone, Skuldelev, Denmark: 1. Site description and contaminant source mass reduction
AU - Fjordbøge, Annika Sidelmann
AU - Riis, Charlotte
AU - Christensen, Anders G.
AU - Kjeldsen, Peter
PY - 2012
Y1 - 2012
N2 - Field investigations on the effects of ZVI-Clay soil mixing were conducted at a small DNAPL source zone with PCE as the parent compound. In a one-year monitoring program, soil samples were collected at three horizontal sampling planes (2.5, 5.0 and 7.5m bgs.). PCE was found to have a pseudo first-order degradation half-life of 47days resulting in more than 99% depletion of the source mass after one year. The main degradation product was ethene, while only low concentrations of the primarily biotic sequential degradation products (cDCE, VC) were detected. The soil mixing resulted in more homogeneous vertical conditions, while the horizontal homogenization was very limited. Iron was delivered in the full targeted depth with an average iron enrichment of 3.1%, and an average decline in the oxidation–reduction potential of more than 500mV. Due to the applied top-down addition of ZVI, the iron content decreased from 4.6% to 2.1% on average over a depth of 5m; hence, there is a potential for optimization of the delivery method. Most in situ technologies are limited by subsurface heterogeneities, whereby the successful dispersion of geological units and contaminants holds great promise for remediation of DNAPL source zones with ZVI-Clay soil mixing.
AB - Field investigations on the effects of ZVI-Clay soil mixing were conducted at a small DNAPL source zone with PCE as the parent compound. In a one-year monitoring program, soil samples were collected at three horizontal sampling planes (2.5, 5.0 and 7.5m bgs.). PCE was found to have a pseudo first-order degradation half-life of 47days resulting in more than 99% depletion of the source mass after one year. The main degradation product was ethene, while only low concentrations of the primarily biotic sequential degradation products (cDCE, VC) were detected. The soil mixing resulted in more homogeneous vertical conditions, while the horizontal homogenization was very limited. Iron was delivered in the full targeted depth with an average iron enrichment of 3.1%, and an average decline in the oxidation–reduction potential of more than 500mV. Due to the applied top-down addition of ZVI, the iron content decreased from 4.6% to 2.1% on average over a depth of 5m; hence, there is a potential for optimization of the delivery method. Most in situ technologies are limited by subsurface heterogeneities, whereby the successful dispersion of geological units and contaminants holds great promise for remediation of DNAPL source zones with ZVI-Clay soil mixing.
KW - ZVI-Clay
KW - Zero valent iron
KW - Soil mixing
KW - Source remediation
KW - Chlorinated solvents
KW - DNAPL
U2 - 10.1016/j.jconhyd.2012.08.007
DO - 10.1016/j.jconhyd.2012.08.007
M3 - Journal article
C2 - 23010546
SN - 0169-7722
VL - 140-141
SP - 56
EP - 66
JO - Journal of Contaminant Hydrology
JF - Journal of Contaminant Hydrology
ER -