Grantee Research Project Results
Final Report: Integration of Filtration and Advanced Oxidation: Development of a Membrane Liquid-Phase Plasma Reactor
EPA Grant Number: R835332Title: Integration of Filtration and Advanced Oxidation: Development of a Membrane Liquid-Phase Plasma Reactor
Investigators: Bellona, Christopher , Holsen, Thomas M. , Dickenson, Eric , Mededovic Thagard, Selma
Institution: Clarkson University , Southern Nevada Water Authority
EPA Project Officer: Packard, Benjamin H
Project Period: August 16, 2012 through August 15, 2016 (Extended to August 15, 2017)
Project Amount: $499,779
RFA: Research and Demonstration of Innovative Drinking Water Treatment Technologies in Small Systems (2011) RFA Text | Recipients Lists
Research Category: Drinking Water , Water
Objective:
Engineer, develop and demonstrate an integrated process comprised of membrane technology and electrical discharge plasma generated via a novel reticulated vitreous carbon (RVC) electrode material. The successful development of this process will result in a technology that is scalable, robust, requires minimal chemical input, has a small foot-print, and achieves a finished water quality better than treatment systems that require multiple technologies.
Summary/Accomplishments (Outputs/Outcomes):
(1) Project Activities and Achievements
The main objective of this study was to engineer, develop and demonstrate an innovative water treatment technology that could potentially replace conventional water treatment unit processes for small water treatment systems. To this end, the objective of this project was to develop and electrical discharge plasma (i.e., non-thermal plasma (NTP)) reactor for the degradation of organic contaminants. NTP offers several advantages over established advanced oxidation processes in that reactive species are generated in situ, and the process requires no chemical additions. Work completed during the course of this project can be broken down into the following main components: a) systematic performance evaluation of NTP reactor configurations; b) evaluation of the optimized NTP reactor design for contaminant degradation; c) effectiveness for destruction of recalcitrant perfluoroalkyl substances; and d) development of a scalable NTP system for field deployment.
A. Systematic NTP Performance Evaluation
To improve the feasibility of plasma-based water treatment technology (i.e., NTP) and develop basic guidelines for reactor design and optimization, work was first conducted to identify and characterize design parameters and physical phenomena that influence treatment efficiency. The first phase of the study established that the chemical reactions responsible for the degradation of organic solutes can be more accurately represented, mathematically, as heterogeneous reactions, rather than the common representation as homogeneous reactions. Using Rhodamine B (RhB) as the model solute, the observed removal rate constant was found to be proportional to the area of the plasma–liquid interface. This observation supported the validity of the proposed heterogeneous rate equation and inspired the conception of a general design principle, which prescribes maximizing contact between the plasma and the treated solution. The second phase of the study involved the application of this design principle to create seven different ‘‘contact-oriented’’ reactors. The design parameters employed to increase contact included feeding liquid streams directly through the discharge region and generating a layer of foam on the liquid surface. The contact-oriented reactors validated the founding principle by achieving removal efficiencies up to 145 times that for the reference case (point-plate with discharge in liquid). The removal efficiencies attained in this work compare quite favorably with those achieved by other advanced oxidation processes for the degradation of RhB.
B. Optimized NTP Reactor Performance
Worked performed during the first project period lead to the development of an optimized reactor design termed the enhanced contact NTP reactor. Work was performed to evaluate the degradation performance of a variety of environmentally relevant organic contaminants (Mededovic Thagard et al. 2017). First-order degradation rate constants obtained through experimentation. Surprisingly, two perfluoroalkyl substances (PFAS), perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), had the largest first-order degradation rate constants among the contaminants tested. Additionally, it was hypothesized that surfactant-like contaminants are generally well degraded by NTP because they interact with the plasma streamers produced during NTP treatment (Mededovic Thagard et al. 2017). The effective removal of PFAS is currently of heightened interest due to widespread contamination, recalcitrance in the environment, lack of effective treatment technologies and human toxicity concerns (Houtz et al. 2013, Hu et al. 2016, Merino et al. 2016). Observed PFOA and PFOS degradation kinetics were evaluated multiple times and the project team concluded that the developed NTP reactor had the potential to be the most current effective PFAS destruction method develop to date.
C. PFAS Destruction with Developed NTP Reactor
The developed NTP reactor was tested for the transformation of PFAS. The NTP process was adapted for two cases, high removal rate and high removal efficiency. During a 30-minute treatment, the PFOA concentration in 1.4 L aqueous solutions was reduced by 90% with the high rate process (76.5 W input power) and 25% with the high efficiency process (4.1 W input power). Both achieved remarkably high PFOA removal and defluorination efficiencies compared to leading alternative technologies. The high efficiency process was also used to treat groundwater containing PFOA and several co-contaminants including perfluorooctane sulfonate (PFOS), demonstrating that the process was not significantly affected by co-contaminants and that the process was capable of rapidly degrading PFOS. Preliminary investigation into the byproducts showed that only about 10% of PFOA and PFOS is converted into shorter-chain perfluoroalkyl acids (PFAAs) (Stratton et al. 2017)
D. Development of a Pilot-scale NTP Reactor for PFAS Treatment
Work commenced in 2016 to develop a larger-scale plasma reactor that would not require recirculation (i.e., flow through reactor; Figure 6). The reactor consists of two ceramic diffuser plates serving as the grounded electrode and two stainless steal rods serving as the high-voltage electrodes. This system was tested on PFAS contaminated groundwater which is summarized in the next section. The research team developed a system to recycle argon gas through the system to reduce argon gas consumption.
Conclusions:
Work completed during the course of this project can be broken down into the following main components: a) systematic performance evaluation of NTP reactor configurations; b) evaluation of the optimized NTP reactor design for contaminant degradation; c) effectiveness for destruction of recalcitrant perfluoroalkyl substances; and d) development of a scalable NTP system for field deployment.
References:
Dai, F., Fan, X., Stratton, G.R., Bellona, C.L., Holsen, T.M., Crimmins, B.S., Xia, X. and Mededovic Thagard, S. (2016) Experimental and density functional theoretical study of the effects of Fenton’s reaction on the degradation of Bisphenol A in a high voltage plasma reactor. Journal of Hazardous Materials 308, 419-429.
Houtz, E.F., Higgins, C.P., Field, J.A. and Sedlak, D.L. (2013) Persistence of Perfluoroalkyl Acid Precursors in AFFF-Impacted Groundwater and Soil. Environmental Science & Technology 47(15), 8187-8195.
Hu, X.C., Andrews, D.Q., Lindstrom, A.B., Bruton, T.A., Schaider, L.A., Grandjean, P., Lohmann, R., Carignan, C.C., Blum, A., Balan, S.A., Higgins, C.P. and Sunderland, E.M. (2016) Detection of Poly- and Perfluoroalkyl Substances (PFASs) in U.S. Drinking Water Linked to Industrial Sites, Military Fire Training Areas, and Wastewater Treatment Plants. Environmental Science & Technology Letters.
Lau, C., Butenhoff, J.L. and Rogers, J.M. (2004) The developmental toxicity of perfluoroalkyl acids and their derivatives. Toxicology and applied pharmacology 198(2), 231-241.
Mededovic Thagard, S., Stratton, G.R., Dai, F., Bellona, C., Holsen, T.M., Bohl, D.G., Paek, E. and Dickenson, E.R.V. (2017) Plasma-based water treatment: development of a general mechanistic model to estimate the treatability of different types of contaminants. Journal of Physics D: Applied Physics 50, 1-13.
Merino, N., Yan, Q., Deeb, R.A., Hawley, E.L., Hoffmann, M.R. and Mahendra, S. (2016) Degradation and removal methods for perfluoroalkyl and polyfluoroalkyl substances in water. Environmental Engineering Science 33(9), 615-649.
Post, G.B., Cohn, P.D. and Cooper, K.R. (2012) Perfluorooctanoic acid (PFOA), an emerging drinking water contaminant: A critical review of recent literature. Environmental Research 116, 93-117.
Schultz, M.M., Barofsky, D.F. and Field, J.A. (2003) Fluorinated Alkyl Surfactants. Environmental Engineering Science 20(5), 487-501.
Stahl, T., Mattern, D. and Brunn, H. (2011) Toxicology of perfluorinated compounds. Environmental Sciences Europe 23(1), 1-52.
Stratton, G.R., Bellona, C.L., Dai, F., Holsen, T.M. and Thagard, S.M. (2015) Plasma-based water treatment: Conception and application of a new general principle for reactor design. Chemical Engineering Journal 273, 543-550.
Stratton, G.R., Dai, F., Bellona, C.L., Holsen, T.M., Dickenson, E.R.V. and Mededovic Thagard, S. (2017) Plasma-Based Water Treatment: Efficient Transformation of Perfluoroalkyl Substances in Prepared Solutions and Contaminated Groundwater. Environmental Science & Technology 51(3), 1643-1648.
Journal Articles on this Report : 5 Displayed | Download in RIS Format
| Other project views: | All 22 publications | 6 publications in selected types | All 6 journal articles |
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Dai F, Fan X, Stratton GR, Bellona CL, Holsen TM, Crimmins BS, Xia X, Mededovic Thagard S. Experimental and density functional theoretical study of the effects of Fenton’s reaction on the degradation of bisphenol A in a high voltage plasma reactor. Journal of Hazardous Materials 2016;308:419-429. |
R835332 (2016) R835332 (Final) |
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Mededovic Thagard S, Stratton GR, Dai F, Bellona C, Holsen TM, Bohl DG, Paek E, Dickenson E. Plasma-based water treatment:development of a general mechanistic model to estimate the treatability of different types of contaminants. Journal of Physics D:Applied Physics 2017; 50:1-13. |
R835332 (Final) |
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Stratton GR, Bellona CL, Dai F, Holsen TM, Mededovic Thagard S. Plasma-based water treatment: conception and application of a new general principle for reactor design. Chemical Engineering Journal 2015;273:543-550. |
R835332 (2015) R835332 (2016) R835332 (Final) |
Exit Exit Exit |
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Stratton GR, Dai F, Bellona CL, Holsen TM, Dickenson ERV, Mededovic Thagard S. Plasma-based water treatment: efficient transformation of perfluoroalkyl substances in prepared solutions and contaminated groundwater. Environmental Science & Technology 2017;51(3):1643-1648. |
R835332 (2016) R835332 (Final) |
Exit Exit Exit |
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Mededovic Thagard, S., Stratton, G.R., Dai, F., Bellona, C., Holsen, T.M., Bohl, D.G., Paek, E. and Dickenson, E.R.V. (2017) Plasma-based water treatment:development of a general mechanistic model to estimate the treatability of different types of contaminants. Journal of Physics D:Applied Physics 50, 1-13. |
R835332 (Final) |
not available |
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.
Project Research Results
- 2016 Progress Report
- 2015 Progress Report
- 2014 Progress Report
- 2013 Progress Report
- Original Abstract
6 journal articles for this project