ZVI-Clay remediation of a chlorinated solvent source zone, Skuldelev, Denmark: 1. Site description and contaminant source mass reduction

ZVI-Clay remediation of a chlorinated solvent source zone, Skuldelev, Denmark: 2. Groundwater contaminant mass discharge reduction

“…The technology significantly changes the hydraulic and chemical properties of the source through soil mixing with the addition of zero valent iron (ZVI) and clay. ZVI results in a significant source mass depletion as described in the companion paper (Fjordbøge et al, 2012). The source mass depletion has also been the primary focus of previous field applications (Bozzini et al, 2006;Ovbey et al, 2010;Shackelford et al, 2005).…”

“…Descriptions of the field site with its seven discrete tetrachloroethene (PCE) source zones and the source mass depletion by ZVI-Clay soil mixing (source zone V) are provided in the companion paper Fjordbøge et al (2012). Prior to the remediation, the soil concentrations of the parent compound PCE were as high as 12,000 mg/kg, and separate phase PCE was extracted from the monitoring well in the central part of the source zone.…”

“…The cores were also examined to identify any low-permeable geologic units in the sandy aquifer, which might cause back-diffusion of stored contaminants. The sampling was conducted by use of a 54 DT Model GeoProbe mounted with a hydraulic hammer as described in more details by Fjordbøge et al (2012).…”

“…The hydraulic gradient and conductivity were determined. Depletion of the contaminant source is described in the companion paper (Fjordbøge et al, 2012). Field data showed four distinct phases for PCE mass discharge: (1) baseline conditions, (2) initial rapid reduction, (3) temporary increase, and (4) slow long-term reduction.…”

“…A two-dimensional (2D) numerical groundwater model has been developed with the objective of improving the conceptual understanding of the mass discharge development and identifying the governing processes. Finally, the mass discharge reduction has been related to the source mass depletion presented in the companion paper (Fjordbøge et al, 2012) using an analytical power law model.…”