Semi-Passive Chemical Oxidation Schemes for the Long-Term Treatment of Contaminants

Schwartz, Frank

Ohio State University

关键词: By-Products;    Ethylene;    Chemical Reactions;    Solutes;    37 Inorganic, Organic, Physical And Analytical Chemistry;   

DOI  :  10.2172/835411
RP-ID  :  EMSP-86642-2003A
RP-ID  :  FG07-02ER63487
RP-ID  :  835411

美国|英语

来源: UNT Digital Library

【 摘 要 】

In situ chemical oxidation or ISCO schemes involve the addition of a chemical oxidant, such as potassium permanganate (KMnO4), which destroys chlorinated solvents like TCE in a straightforward reaction. Although ISCO is now regarded as a developing technology in an industrial sense, beyond active flushing schemes, there have been relatively limited investigations in how ISCO might be better used. Our previous study showed that KMnO4 flushing approaches often would be frustrated by the inability to control the delivery of the treatment fluid due to precipitation of low-permeability reaction by-product like MnO2 and other problems. It was therefore suggested that development of a new ISCO scheme that can provide both destruction efficiencies and plugging control would be required. The goal of our current study is to develop a scientific basis for the use of new semi-passive, well-based ISCO systems for treating chlorinated ethylene in groundwater. More specifically, our work examines the possibilities of developing a slow release KMnO4 scheme. This scheme could be operated in a semi-passive manner with periodic additions of the slow-release KMnO4 solids into well-delivery systems. To our knowledge, a system of this type has not been demonstrated. Our current scientific work is then concerned with how to manufacture the slow release KMnO4 solids, how the well systems can be designed, and how they interact with the flow systems to maximize spreading. To achieve these goals, development of numerical models to simulate solute transport coupled with NAPL dissolution and chemical reaction with the oxidant is required. There is also a need for ways to control the local precipitation of MnO2 that could cause plugging near the wells, or at least remove the plugging materials. Moreover, the likely extent of spreading of KMnO4 added by the wells must be understood. Finally, the spacing of wells will depend in part how far KMnO4 ends up spreading away from the treatment zone. Thus, a geochemical study as to the reaction kinetics involving KMnO4 and natural aquifer materials including carbonates, metals, and natural organic matter is also required. We feel that research of the type we are conducting with the current DOE grant is vital to advancing the remediation technology to the industrial phase.