Semi-passive, Chemical Oxidation Schemes for the Long-term Treatment of Contaminants
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.
- Research Organization:
- The Ohio State University Research Foundation
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- FG07-02ER63487
- OSTI ID:
- 861451
- Report Number(s):
- DOE/ER/63487; TRN: US200710%%54
- Country of Publication:
- United States
- Language:
- English
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