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1999 Progress Report: Innovations in Vapor Phase Bioreactor Design
EPA Grant Number: R826168Title: Innovations in Vapor Phase Bioreactor Design
Investigators: Kinney, Kerry A.
Institution: University of Texas at Austin
EPA Project Officer: Shapiro, Paul
Project Period: December 1, 1997 through November 30, 2000
Project Period Covered by this Report: December 1, 1998 through November 30, 1999
Project Amount: $293,809
RFA: Exploratory Research - Environmental Engineering (1997)
Research Category: Engineering and Environmental Chemistry
Description:
Objective:The objectives of the research project are to: (1) develop an efficient, vapor phase bioreactor (VPB) that will operate reliably over long periods of operation; and (2) characterize the temporal and spatial distribution of active biomass in these bioreactor systems. Conventional bioreactor systems do not adequately control several important operating parameters such as biomass distribution, biomass activity, and nutrient/moisture levels within the biofilm. These simple systems work acceptably during short-term tests in the laboratory, but fail to ensure reliable long-term performance in the field where process variables fluctuate widely. Typically, these systems are analyzed using a black box approach and the activity of the biomass responsible for the pollutant degradation remains uncharacterized. In this study, the effect of three design features on bioreactor performance, biomass distribution, and biomass activity in toluene-degrading bioreactors are being investigated; these features include directionally switching operation, slip stream feed, and an aerosol delivery system. Progress Summary:
This research project is being conducted in three study phases: Phase 1, Directionally Switching Experiments; Phase 2, Nutrient Aerosol Experiments; and Phase 3, Slip Feed Experiments. All three phases are being conducted simultaneously and are nearing completion. Study results indicate that directionally switching operation greatly enhances the stability and long-term performance of vapor phase bioreactors by providing a more even distribution of active biomass throughout the bioreactor column. An evaluation of the effect of switching frequency on bioreactor performance indicates that a 3-day switching frequency provides the most stable contaminant removal efficiencies and the highest contaminant elimination capacities. Experiments with the nutrient aerosol delivery system indicate that this system can effectively deliver nutrients and moisture to vapor phase bioreactors packed with natural or synthetic materials. The nutrient aerosol system also can be used to regenerate contaminant degradation capacity in a bioreactor that has become nutrient-limited. Study results also confirm that the slip feed system can be used to maintain biomass activity during bioreactor shutdown periods. The bioreactor equipped with a slip feed system required approximately 70 percent less time to recover full contaminant degradation capacity following a 7-day process shutdown.
In addition to the progress cited above, this study has also served as the catalyst for innovative research that extends beyond the scope of the original project. For instance, the Principal Investigator now has several studies underway to evaluate fungal bioreactors based on work conducted during the preliminary phase of this Environmental Protection Agency (EPA)-funded study. One of these studies is being funded by a National Science Foundation (NSF) CAREER award that the Principal Investigator received last year to pursue this line of research. Experimental results indicate that fungal bioreactors can achieve contaminant elimination capacities up to an order of magnitude higher than comparable bacterial systems and are much more resistant to adverse operating conditions.
Three graduate students and two undergraduate students have received extensive research training as a result of this EPA-funded project. Based on their research efforts, two of the graduate students will complete their Masters degrees in August and the third student will finish his Ph.D. degree in December. Of the two undergraduate research assistants, one has graduated with a degree in chemical engineering and now works in the environmental engineering field; the second student will be completing her final year in the Civil Engineering program at the University of Texas at Austin next fall.
Future Activities:Final experiments are currently underway to further evaluate the effectiveness of the directionally switching, slip feed, and nutrient aerosol systems. In addition, a model that incorporates the effect that active and inactive biomass have on bioreactor performance is being developed. With the aid of additional funding from other sources, the scope of the research effort is being expanded to examine the effect of contaminant mixtures on bioreactor performance, and a fungal bioreactor is being developed to treat volatile organic compound (VOC)-contaminated air.
Journal Articles on this Report: 2 Displayed | Download in RIS Format
| Other project views: | All 16 publications | 5 publications in selected types | All 5 journal articles |
| Type | Citation | ||
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Song J, Kinney KA. An evaluation of the effect of directionally-switching frequency on vapor phase bioreactor performance. Applied Microbiology and Biotechnology 2000. |
R826168 (1999) |
not available |
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Song J, Kinney KA. Effect of vapor-phase bioreactor operation on biomass accumulation, distribution, and activity: linking biofilm properties to bioreactor performance. Biotechnology and Bioengineering 2000;68(5):508-516. |
R826168 (1999) R826168 (Final) R826128 (Final) |
not available |
fungal bioreactor, biomass activity, VOC , Air, Scientific Discipline, Engineering, Chemistry, & Physics, air toxics, Environmental Engineering, Environmental Chemistry, treatment, biomass, chemical treatment, biofilms, environmental contaminants, biotrickling filters, air sampling, airborne suspension, atmospheric particles, emission control technologies, cost effective, biofiltration systems, VOCs, vapor phase bioreactors, directionally-switching parameters
Progress and Final Reports:
1998 Progress Report
Original Abstract
Final Report