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Title: Semi-passive, Chemical Oxidation Schemes for the Long-term Treatment of Contaminants

Abstract

This research involves a combined experimental and modeling study that builds on our previous DOE-sponsored work in investigating how KMnO{sub 4} can be better used with in situ remediation of groundwater contaminated by chlorinated ethylenes (e.g., PCE, TCE, DCE). This study aims to provide scientific basis for developing a new long-term, semi-passive ISCO scheme that uses controlled release KMnO{sub 4} as a reactive barrier component. Specific objectives of the study are (1) to construct controlled release KMnO{sub 4} as a new reactive barrier component that could deliver permanganate at a controlled rate over long time periods of years, (2) to quantitatively describe release mechanisms associated with the controlled release KMnO{sub 4}, (3) to demonstrate efficacy of the new remediation scheme using proof-of-concept experiments, and (4) to design advanced forms of controlled release systems through numerical optimization. The new scheme operates in a long-term, semi-passive manner to control spreading of a dissolved contaminant plume with periodic replacement of the controlled release KMnO{sub 4} installed in the subsurface. As a first step in developing this remedial concept, we manufactured various prototype controlled release KMnO{sub 4} forms. Then we demonstrated using column experiments that the controlled release KMnO{sub 4} could deliver small amountmore » of permanganate into flowing water at controlled rates over long time periods of years. An analytical model was also used to estimate the diffusivities and durations of the controlled release KMnO{sub 4}. Finally, proof-of-concept flow-tank experiments were performed to demonstrate the efficacy of the controlled release KMnO{sub 4} scheme in controlling dissolved TCE plume in a long-term, semi-passive manner. Another important thrust of our research effort involved numerical optimization of controlled release systems. This study used a numerical model that is capable of describing release patterns of active agent from controlled release systems of varied forms and applications. We manufactured prototype single- and double-layered matrix-type controlled release systems and tested their release patterns using numerical simulations and column experiments. In a series of simulations, we demonstrated that an encapsulated, dispersed-agent polymeric matrix-type controlled release system could deliver active agent at a predetermined constant rate for long time periods of years and decades. Such long-term, constant release system is useful in the construction of fertilizers, herbicides, or implantable drug delivery devices as well as in subsurface treatment. Construction of more advanced forms of controlled release systems is currently under way.« less

Authors:
Publication Date:
Research Org.:
The Ohio State University Research Foundation
Sponsoring Org.:
USDOE
OSTI Identifier:
861451
Report Number(s):
DOE/ER/63487
TRN: US200710%%54
DOE Contract Number:
FG07-02ER63487
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; CHLORINATED ALIPHATIC HYDROCARBONS; REMEDIAL ACTION; GROUND WATER; PERMANGANATES; POTASSIUM COMPOUNDS; CONTAINMENT SYSTEMS; DESIGN; OXIDATION; FLOW MODELS

Citation Formats

Frank W. Schwartz. Semi-passive, Chemical Oxidation Schemes for the Long-term Treatment of Contaminants. United States: N. p., 2005. Web. doi:10.2172/861451.
Frank W. Schwartz. Semi-passive, Chemical Oxidation Schemes for the Long-term Treatment of Contaminants. United States. doi:10.2172/861451.
Frank W. Schwartz. Tue . "Semi-passive, Chemical Oxidation Schemes for the Long-term Treatment of Contaminants". United States. doi:10.2172/861451. https://www.osti.gov/servlets/purl/861451.
@article{osti_861451,
title = {Semi-passive, Chemical Oxidation Schemes for the Long-term Treatment of Contaminants},
author = {Frank W. Schwartz},
abstractNote = {This research involves a combined experimental and modeling study that builds on our previous DOE-sponsored work in investigating how KMnO{sub 4} can be better used with in situ remediation of groundwater contaminated by chlorinated ethylenes (e.g., PCE, TCE, DCE). This study aims to provide scientific basis for developing a new long-term, semi-passive ISCO scheme that uses controlled release KMnO{sub 4} as a reactive barrier component. Specific objectives of the study are (1) to construct controlled release KMnO{sub 4} as a new reactive barrier component that could deliver permanganate at a controlled rate over long time periods of years, (2) to quantitatively describe release mechanisms associated with the controlled release KMnO{sub 4}, (3) to demonstrate efficacy of the new remediation scheme using proof-of-concept experiments, and (4) to design advanced forms of controlled release systems through numerical optimization. The new scheme operates in a long-term, semi-passive manner to control spreading of a dissolved contaminant plume with periodic replacement of the controlled release KMnO{sub 4} installed in the subsurface. As a first step in developing this remedial concept, we manufactured various prototype controlled release KMnO{sub 4} forms. Then we demonstrated using column experiments that the controlled release KMnO{sub 4} could deliver small amount of permanganate into flowing water at controlled rates over long time periods of years. An analytical model was also used to estimate the diffusivities and durations of the controlled release KMnO{sub 4}. Finally, proof-of-concept flow-tank experiments were performed to demonstrate the efficacy of the controlled release KMnO{sub 4} scheme in controlling dissolved TCE plume in a long-term, semi-passive manner. Another important thrust of our research effort involved numerical optimization of controlled release systems. This study used a numerical model that is capable of describing release patterns of active agent from controlled release systems of varied forms and applications. We manufactured prototype single- and double-layered matrix-type controlled release systems and tested their release patterns using numerical simulations and column experiments. In a series of simulations, we demonstrated that an encapsulated, dispersed-agent polymeric matrix-type controlled release system could deliver active agent at a predetermined constant rate for long time periods of years and decades. Such long-term, constant release system is useful in the construction of fertilizers, herbicides, or implantable drug delivery devices as well as in subsurface treatment. Construction of more advanced forms of controlled release systems is currently under way.},
doi = {10.2172/861451},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Dec 13 00:00:00 EST 2005},
month = {Tue Dec 13 00:00:00 EST 2005}
}

Technical Report:

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  • 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 developmentmore » 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.« less
  • This study aims to provide basic research on a new passive remediation concept based on an in situ chemical oxidation scheme. The first objective is to use laboratory experiments and computer simulations to develop a new semi-passive delivery system for the controlled release of KMnO4. A system is required to facilitate the slow release of KMnO4 into flowing ground water in a manner that maximizes the lateral spreading, and minimizes the number of wells. The second objective is to use laboratory experiments to assess whether chemical mixtures or cyclic chemical renovation schemes are capable of providing both contaminant destruction andmore » plugging control. Preliminary experiments have identified compounds capable of delaying precipitation or dissolving precipitates. We have hopes that even in with a passive scheme that plugging can be controlled in the immediate vicinity of wells. The third objective is to evaluate the kinetics of interactions among treatment chemicals and the porous medium in order to optimize design. It is well known that natural, oxidizable compounds in aquifer materials utilize KMnO4. The well design requires knowledge concerning the fate and transport of KMnO4.« less
  • As of the third year of this 3-year project, we have developed numerical models and performed a series of computer simulations to investigate the problems related to the delivery of permanganate to the saturated porous media. Primary results of this study are being prepared for presentation in national conferences and as papers in peer-reviewed publications. In addition, we have assessed the capabilities of various types of chemical mixtures in providing both contaminant destruction and plugging control. Results of this study have been published in peer-review journals.
  • As of the third year of this 3-year project, we have developed numerical models and performed a series of computer simulations to investigate the problems related to the delivery of permanganate to the saturated porous media. Primary results of this study are being prepared for presentation in national conferences and as papers in peer-reviewed publications. In addition, we have assessed the capabilities of various types of chemical mixtures in providing both contaminant destruction and plugging control. Results of this study have been published in peer-review journals.
  • 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 developmentmore » of a new ISCO scheme that can provide both destruction efficiencies and plugging control would be required.« less