Full metadata
Title
Trade-offs in utilizing of zero-valent iron for synergistic biotic and abiotic reduction of trichloroethene and perchlorate in soil and groundwater
Description
The advantages and challenges of combining zero-valent iron (ZVI) and microbial reduction of trichloroethene (TCE) and perchlorate (ClO4-) in contaminated soil and groundwater are not well understood. The objective of this work was to identify the benefits and limitations of simultaneous application of ZVI and bioaugmentation for detoxification of TCE and ClO4- using conditions relevant to a specific contaminated site. We studied conditions representing a ZVI-injection zone and a downstream zone influenced Fe (II) produced, for simultaneous ZVI and microbial reductive dechlorination applications using bench scale semi-batch microcosm experiments. 16.5 g L-1 ZVI effectively reduced TCE to ethene and ethane but ClO4- was barely reduced. Microbial reductive dechlorination was limited by both ZVI as well as Fe (II) derived from oxidation of ZVI. In the case of TCE, rapid abiotic TCE reduction made the TCE unavailable for the dechlorinating bacteria. In the case of perchlorate, ZVI inhibited the indigenous perchlorate-reducing bacteria present in the soil and groundwater. Further, H2 generated by ZVI reactions stimulated competing microbial processes like sulfate reduction and methanogenesis. In the microcosms representing the ZVI downstream zone (Fe (II) only), we detected accumulation of cis-dichloroethene (cis-DCE) and vinyl chloride (VC) after 56 days. Some ethene also formed under these conditions. In the absence of ZVI or Fe (II), we detected complete TCE dechlorination to ethene and faster rates of ClO4- reduction. The results illustrate potential limitations of combining ZVI with microbial reduction of chlorinated compounds and show the potential that each technology has when applied separately.
Date Created
2017
Contributors
- Mohana Rangan, Srivatsan (Author)
- Krajmalnik-Brown, Rosa (Thesis advisor)
- Delgado, Anca G (Committee member)
- Lowry, Gregory V. (Committee member)
- Arizona State University (Publisher)
Topical Subject
Resource Type
Extent
v, 23 pages : illustrations (some color)
Language
eng
Copyright Statement
In Copyright
Primary Member of
Peer-reviewed
No
Open Access
No
Handle
https://hdl.handle.net/2286/R.I.45527
Statement of Responsibility
by Srivatsan Mohana Rangan
Description Source
Viewed on March 6, 2018
Level of coding
full
Note
thesis
Partial requirement for: M.S., Arizona State University, 2017
bibliography
Includes bibliographical references (pages 20-23)
Field of study: Civil, environmental and sustainable engineering
System Created
- 2017-10-02 07:19:38
System Modified
- 2021-08-26 09:47:01
- 3 years 2 months ago
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