HR: 0800h
AN: B41B-08    [Abstracts]
TI: Transport of Oil-in-Water Emulsions Designed to Deliver Reactive Iron Particles in Porous Media
AU: * Crocker, J J
EM: jonathan.crocker@tufts.edu
AF: Tufts University, 200 College Avenue Room 113 Anderson Hall, Medford, MA 01867, United States
AU: Berge, N D
EM: nicole.berge@tufts.edu
AF: Tufts University, 200 College Avenue Room 113 Anderson Hall, Medford, MA 01867, United States
AU: Ramsburg, C A
EM: andrew.ramsburg@tufts.edu
AF: Tufts University, 200 College Avenue Room 113 Anderson Hall, Medford, MA 01867, United States
AB: Treatment of subsurface regions contaminated with DNAPL is a significant challenge to environmental restoration. The focus of remediation has recently shifted from technologies that recover the contamination to technologies that destroy the contamination in situ. One method of in situ contaminant destruction employs nano- or submicron-size particles of reactive iron metal. Application of iron-based destruction technologies is currently limited by poor delivery of the reactive particles (i.e., lack of contact between the iron particles and the DNAPL). Encapsulation of the reactive particles within an oil-in-water emulsion is a novel approach that may facilitate delivery. The goal of this project was to investigate the transport behavior of emulsions (Tallow oil, Tween 80, and Span 80) within porous media. One-dimensional column experiments were conducted to evaluate pore-clogging when emulsions containing encapsulated reactive particles were passed through two homogeneous sands with an order of magnitude difference in intrinsic permeability. In these experiments, passing an emulsion through the sand column (4.8 cm i.d.) at a constant flow rate (0.86 mL/min) increased the hydraulic gradient by a factor of approximately three. The hydraulic gradient in each experiment was observed to stabilize after one pore volume of emulsion. Subsequent flushing with water recovered the initial hydraulic gradient. Together, these observations indicate that conductivity reductions during emulsion flushing were the result of viscosity and not the result of extensive pore-clogging. Analysis of effluent samples confirmed that there was minimal retention of the emulsion within the sand column. Results from these experiments suggest that emulsion encapsulation may be an effective means for transporting reactive iron particles within the subsurface environment.
DE: 1831 Groundwater quality
DE: 1832 Groundwater transport
SC: Biogeosciences [B]
MN: 2007 Joint Assembly