Field Column Study Using Zerovalent Iron for Mercury Removal from Contaminated Groundwater

Passive in situ remediation technologies, for example, permeable reactive barriers, PRBs, are an attractive and less expensive alternative compared to conventional pump and treat systems for groundwater remediation. Field column experiments were conducted to evaluate the removal of dissolved mercury from groundwater using zerovalent iron as the reactive media. Two column tests were conducted over a 6-week period, which simulated 2 and 10 years of groundwater flow through a potential full-scale treatment system. The influent groundwater pH was 7.8−9.5. The groundwater was reduced with an Eh, corrected to the standard hydrogen electrode, ranging from 0 to 120 mV over the trial period. Prior to treatment the total mercury concentration of the groundwater was approximately 40 μg L-1. Effluent from the 10-year simulation contained approximately 0.5 μg/L of mercury during the first 3 weeks and increased to as much as 4 μg L-1 by the end of the testing period. Effluent from the 2-year simulation was generally