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(e)) measured in-situ between two 37 m deep wells, 3 m apart of 2.3 x 10(-9) m /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(-9) m(2)/s-V. Hydraulic conductivity (k(h)) of the same core is measured to be 2.03 +/- 0.36 x 10(-10) m/s. Thus, a voltage gradient of 1 V/cm produces an effective hydraulic conductivity of similar to 1 x 10(-7) m/s; an increase in conductivity of nearly three orders of magnitude.