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Yongje Kim, KIGAM (Republic of Korea)
Eung Seok Lee, The Ohio State University (United States)
Ganming Liu, The Ohio State University (United States)
Franklin Schwartz, The Ohio State University (United States)
Motomu Ibaraki, The Ohio State University (United States)
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This study is to investigate a semi-passive scheme for groundwater remediation, which involves a controlled-release system to control spreading of dissolved organic plumes. Functionally, a reactive barrier system is created by installing solid rods in bore holes across the downstream nose of a plume. These engineered solids slowly dissolve and release an active agent at a controlled rate into the ambient flow to affect the in situ destruction of organic contaminants. This controlled-release approach can be adapted to the treatment of different types of contaminants by appropriate selection of the active agent.
Different aspects of this method have been studied using a variety of investigative approaches. An experimental study by Lee and Schwartz (2007a) described the possibilities for releasing an oxidant (potassium permanganate: ) from various solid forms in a controlled and predictable manner and destroying dissolved plumes of chlorinated solvents like trichloroethylene (TCE) and dichloroethylene (DCE) in groundwater. In subsequent studies, a generalized modeling approach was developed to explain and to provide a basis for designing the release pattern of active agent from solid forms of variable designs (Lee and Schwartz, 2007b). Proof-of-concept experiments with a large pilot-scale system verified the capability of the controlled-release system to control the spread of chlorinated solvents like TCE and DCE (Lee et al., 2007).
An important next step in developing this remedial concept is to provide a capability for modeling controlled-release systems to fully explore issues involving the release and mixing of active agents in complex aquifer settings and the overall performance of such a system. The computer code, which was developed in this study, simulates various implementations of controlled-release systems. Of particular interest are key questions bearing on the application of controlled-release systems, namely the difficulties in mixing released agent within a contaminant plume, possible engineering approaches to promote mixing, and controls on the size of treatment zones. For this study, we used as active agent in the controlled-release system. The development of this general code also opens possibilities for exploring other types of reactive barriers created by reductants, nutrients, bioactive agents, and agents for in situ redox manipulations.
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