Electro-Osmotic Remediation of Fine-Grained Sediments.

The coupled-flow phenomenon, electro-osmosis, whereby water flow results from an applied electrical potential gradient, is being used at Lawrence Livermore National Laboratory to induce water flow through deep (25-40 meters below surface) fine-grained sediments. The scoping work described here lays the groundwork for implementation of this technology to remediate solvent-contaminated clayey zones at the LLNL site. The electro-osmotic conductivity (k{sub e}) measured in-situ between two 37 m deep wells, 3 m apart of 2.3 x 10{sup -9} m{sup 2}/s-V is in good agreement with the value determined from bench-top studies on the core extracted from one of the wells of 0.94 {+-} 0.29 x 10{sup -9} m{sup 2}/s-V. Hydraulic conductivity (k{sub h}) of the same core is measured to be 2.03 {+-} 0.36 x 10{sup -10} m/s. Thus, a voltage gradient of 1 V/cm produces an effective hydraulic conductivity of {approx}1 x 10{sup -7} m/s; an increase in conductivity of nearly three orders of magnitude.