Integrated Electrochemical Soil Remediation

1. Integrated Electrochemical Soil Remediation Investigator: Krishna R. Reddy, Department of Civil & Materials Engineering Prime Grant Support: National Science Foundation • More than 500,000 contaminated sites exist in the U.S. that require urgent remediation to protect public health and the environment • Existing technologies are ineffective or expensive for the remediation of mixed contamination (any combination of toxic organic chemicals, heavy metals, and radionuclides) in heterogeneous/low permeability subsurface environments • Innovative and effective new technologies are urgently needed • Chemical oxidation can destroy organic contaminants, while electrokinetic remediation can remove heavy metals • Integration of chemical oxidation and electrokinetic remediation is proposed to accomplish simultaneous: • Electroosmotic delivery of the oxidant into homogeneous and heterogeneous soils to destroy organic contaminants • Removal of heavy metals by electromigration and electroosomosis processes • Fundamental processes and field implementation considerations are being investigated through bench-scale experiments, mathematical modeling, and field pilot-scale testing • Bench-scale experiments revealed that: • Oxidants such as hydrogen peroxide can be introduced into clay soils effectively based on electroosomosis process. Native iron in soils can be utilized as catalyst in Fenton-like reactions. Organic compounds such as PAHs can be destroyed. • Heavy metals such as mercury and nickel can electromigrate towards the electrode wells and then be removed. • Electrical energy consumption is low • On-going research evaluating field contaminated soils, optimization of the process variables, mathematical modeling, and planning of field pilot-scale test.