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Evaluation of Co-metabolic Removal of Trichloroethylene in a Biotrickling Filter under Acidic Conditions

Chheda, Dhawal
http://orcid.org/0000-0002-8025-4902
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1458900120

Abstract Details

2016, MS, University of Cincinnati, Engineering and Applied Science: Environmental Engineering.
Trichloroethylene (TCE) is a widely used industrial solvent and one of the most frequently detected volatile organic compounds (VOCs) in water, air and soil. Its harmful health effects on humans affecting every core systems of the body and its potential carcinogenicity makes TCE a toxic compound whose removal from these vital resources is necessary. Biotrickling filters have proven to be more economic and efficient while eradicating harmful VOCs as compared to other technologies like incineration. This research analyzes the effectiveness of biotrickling filtration technology to biodegrade TCE from the feed air streams. Two biotrickling filters were seeded with fungi strains and were maintained at pH 4 by a nutrient solution containing formate buffer, crucial minerals and vitamins. This solution was nozzle sprayed on the bed at a rate of 2 L/d. The air streams entered the systems at an empty bed residence time of 2 mins. These streams were spiked with the liquid VOCs through syringe pumps. Furthermore, as TCE is a hydrophobic non-beneficial carbon source for microbes, starvation was chosen as the biomass control strategy. Initially, a spatial analysis was performed using ArcGIS to study TCE distribution across mainland USA and the industrial discharge per individual state for 2007. According to the density maps obtained, the Midwestern, Eastern and Pacific Western states were particularly contaminated with TCE, with most of the densely contaminated locations coinciding with Superfund sites. Subsequently, the co-metabolic removal of TCE in biotrickling filter systems was assessed with the feed consisting TCE and methanol (co-metabolite). Two biotrickling filters were fed with different methanol:TCE ratios – Biofilter I with 70:30 feed ratio and Biofilter II with 80:20 ratio. Each system was fed with various influent VOC concentrations distributed across four phases each. The main objective of this study was to obtain the VOC loading rates at which efficient elimination of TCE can be achieved. The effect of a primary substrate on TCE oxidation in a biotrickling filter was studied. Thereafter, the impact of a ternary mixture of VOCs (toluene, methanol and TCE) on TCE’s oxidation in the same systems was assessed. While most studies evaluate biotrickling filters with feed of a solo or a binary mixture of VOCs, the industrial discharges often have a more complex mixture. Therefore, it is essential to gauge the response of biofilters when a ternary mixture is loaded. Toluene was selected as the third VOC because most industries releasing TCE, emit toluene and methanol along with it. The two trickle bed air biofilters were each supplied with a different ratio of toluene:methanol:TCE – Biofilter I with 45:40:15 and Biofilter II with 50:24:26. Each system was tested for three phases, with increasing TCE concentrations from Phase “A” to “C”. It was observed that the elimination capacity of TCE is highly dependent on the influent composition ratio and loading rates, especially of the primary substrates. Starvation could be successfully applied to the biosystems to control any excess growth of biomass and fungi strains were effective in removing TCE at higher kinetics than literature.
George Sorial, Ph.D. (Committee Chair)
Pablo Campo, Ph.D. (Committee Member)
Margaret Kupferle, Ph.D. P.E. (Committee Member)
81 p.
Environmental Engineering
Biotrickling Filter; Fungi; Methanol; Trichloroethylene; Toluene; Biodegradation

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Citations

  • Chheda, D. (2016). Evaluation of Co-metabolic Removal of Trichloroethylene in a Biotrickling Filter under Acidic Conditions [Master's thesis, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1458900120

    APA Style (7th edition)

  • Chheda, Dhawal. Evaluation of Co-metabolic Removal of Trichloroethylene in a Biotrickling Filter under Acidic Conditions. 2016. University of Cincinnati, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1458900120.

    MLA Style (8th edition)

  • Chheda, Dhawal. "Evaluation of Co-metabolic Removal of Trichloroethylene in a Biotrickling Filter under Acidic Conditions." Master's thesis, University of Cincinnati, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1458900120

    Chicago Manual of Style (17th edition)

ucin1458900120
602
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This open access ETD is published by University of Cincinnati and OhioLINK.