Remediation of Soils Contaminated with Metals

Program Projects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116 3.11 Electrokinetics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116 3.11.1 Process Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116 3.11.2 Site Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119 3.11.3 Applicability and Demonstration Projects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119 3.11.4 Performance and Cost . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122 3.11.5 Summary of Electrokinetic Remediation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123 3.12 Phytoremediation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124 3.12.1 Process Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125 3.12.2 Applicability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128 3.12.3 Performance and Cost . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128 3.12.4 Summary of Phytoremediation Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130 3.13 Use of Treatment Trains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131 3.14 Cost Ranges of Remedial Technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133 Metals account for much of the contamination found at hazardous waste sites. They are present in the soil and groundwater at approximately 65% of the Superfund or CERCLA (Comprehensive Environmental Response, Compensation, and Liability Act)1 sites for which the U.S. Environmental Protection Agency (U.S. EPA) has signed records of decisions (RODs).2 The metals most frequently identifi ed are lead, arsenic, chromium, cadmium, nickel, and zinc. Other metals often identifi ed as contaminants include copper and mercury. In addition to the Superfund program, metals make up a signifi cant portion of the contamination requiring remediation under the Resource Conservation and Recovery Act (RCRA)3 and contamination present at federal facilities, notably those that are the responsibility of the Department of Defense (DOD) and the Department of Energy (DOE).