Experimental Study of Biodegradation of Ethanol and Toluene Vapors

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Table C-1. Dimensions of the stirred tank bioreactor Property Value Reactor diameter 0.247 m Reactor height 0.320 m Number of impellers 2 Position of impellers 0.05, 0.18 m (from bottom) Impeller diameter 0.06 m Blade width 0.01 m Volume 0.014 m 3 182
Appendix C-2. Fed-batch Operation Batch growth experiments performed at very high substrate concentrations often result in very poor bacterial biomass yield because of substrate inhibition, oxygen insufficiency, and the generation of toxic metabolic byproducts. Fed-batch processes are often employed in fermentation to minimize substrate inhibition, or to avoid oxygen insufficiency and possible overheating (resulting from high biomass growth). In this study, a working medium volume of 1.5 L was added to the bioreactor for fed-batch operation. The inoculum was prepared in shake flasks using the same chemical as the growth substrate (See Section 3.2.3 for preparation procedure) and then transferred into the bioreactor at time zero. The substrate, ethanol, was continuously introduced from a contaminated air stream. The ethanol gas concentrations both in the inlet and outlet gas streams were measured and in the liquid phase as well. An ethanol inlet concentration of 25.0 mg/L was introduced into the bioreactor at an air flowrate of 0.4 L/min with a working volume of 1.5 L. Figure C-2 shows a fed-batch operation conducted at 450 RPM and 25.0°C. Initially, ethanol metabolism was low and the ethanol concentration in the liquid increased similar to an ethanol mass transfer alone (shown by the straight line in Figure C-2). After about three hours, biomass growth for the next five hours prevented further build-up of ethanol in the liquid phase. 183
Page 1 and 2:
BIOREMEDIATION OF VOLATILE ORGANIC
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ABSTRACT The mass transfer of ethan
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effect on the growth of P. putida.
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ACKNOWLEDGMENT Of the countless peo
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TABLE OF CONTENTS PERMISSION TO USE
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4.3 Batch Growth on Ethanol and Ben
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LIST OF FIGURES Figure 3-1. Schemat
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Figure 5.3 (b) Simulation of ethano
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Figure 5-16. Continuous removal of
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NOMENCLATURE a - Interfacial area,
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CHAPTER ONE - INTRODUCTION 1.1 Air
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esults (van Groenestijn and Hesseli
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experimental results are presented
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Table 2.2 VOC Emissions in the U.S.
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(paint shop effluents, for instance
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combustion provides 70 to 90% air p
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used to degrade ethanol vapours and
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g m -3 . This would suggest that th
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treatment, This excessive biomass f
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The simultaneous degradation of tol
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emoves only water-soluble gases. Wa
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2.2.6 Pseudomonas It is well known
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2.3.2 Growth Models with Inhibition
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where µ is the total specific grow
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2.4.1 Batch Reactor In a batch reac
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discharged from the other end. The
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element solution consisted of (gram
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growth on ethanol, 20-48 hours for
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Gas phase samples of toluene were c
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Inlet sampler Exit sampler To fume
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Once the oxygen meter indicated a s
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centrifuged and the supernatant was
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where k L a is the volumetric mass
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Figure 4-2a shows ethanol liquid co
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coefficient (k L a) in the well-mix
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calculated by dividing the gas volu
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Average bubble diameter, mm 8 7 6 5
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Bioflow III bioreactor. Equation (4
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3.5 y=Ln(S0/S) 3 2.5 2 1.5 1 y = 12
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Ethanol and biomass concentration,
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4.3.2 Batch Growth on Benzyl Alcoho
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Biomass and benzyl alcohol concentr
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ethanol loading was beyond the maxi
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Table 4-2. Comparison of bioremedia
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Biomass, benzyl alcohol and toluene
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4.4.3 Toluene-ethanol Bioremediatio
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Substrate and biomass concentration
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Biomass and benzyl alcohol concentr
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Biomass and benzoic acid concentrat
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ethanol. These results clearly indi
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CHAPTER FIVE - MATHEMATICAL MODELIN
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The stoichiometry of the biomass sy
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synthesis and in the ethanol catabo
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1 max Y ex = − 0.635 + 2δ + K 3
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Biomass Eq.5-18 Benzyl Alcohol Eq.5
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r x r N -1.27 -1 0 1 0 0 -0.2 0 0 2
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φ = −θ b ⋅ν (5-31) φ b = 1.
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The data sets used to evaluate the
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Figures 5.4a and 5.4b present 95% c
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Ethanol and biomass concentration (
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Ethanol measured (C-mol/L) 0.3 0.25
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Figures 5.5 (a-d) demonstrate the s
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Benzyl alcohol and biomass concentr
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Benzyl alcohol measured (C-mol/L) 0
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x = 5 ∑ i= 1 x N i (5-40) where x
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ethanol in a steady state mode is l
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where ν 1 , ν 2 , ν 3, ν 4 are
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Biomass concentration, g/L 1.5 1 0.
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φ T =ν 4 (5-53b) φx = −ν 1 (5
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In this study, a metabolic model ha
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Equations (5-34) and (5-35) and the
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ATP 1 = Y max ATP r x + m ATP ⋅ C
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Ethanol, biomass and ammonium conce
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Figure 5-13a shows that the lower t
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Biomass, substrate concentrations,
Page 151 and 152: C e DKe = (5-63) μ − D m Equatio
Page 153 and 154: corresponds with the value associat
Page 155 and 156: Biomass and ethanol concentrations
Page 157 and 158: than 4.0 mg/L at all dilution rates
Page 159 and 160: Biomass, benzyl alcohol and ammonia
Page 161 and 162: negligible ( y out , e = 0) , and e
Page 163 and 164: Figure 5-17 shows the results at a
Page 165 and 166: Biomass Concentrations, g/L 3.5 3 2
Page 167 and 168: C x ( 1 max Q max = ⋅{ D( Cb0 −
Page 169 and 170: 1.2 g/L, the system could not be op
Page 171 and 172: The continuous models can capture a
Page 173 and 174: • Air stripping coefficients obta
Page 175 and 176: Toluene acts as an inhibitor on the
Page 177 and 178: Bruining, W. J., G. E. H. Joosten,
Page 179 and 180: Falatko, D. M., and J. T. Novak, 19
Page 181 and 182: Keuning, S., and D. Jager, 1994.
Page 183 and 184: Orshansky, F., and N. Narkis, 1997.
Page 185 and 186: Togna, A. P, M. Singh, 1994. “Bio
Page 187 and 188: APPENDIX A. Important Metabolic Pat
Page 189 and 190: III. Toluene Pathway (Adapted from
Page 191 and 192: Appendix B. Calibration Procedure a
Page 193 and 194: Figure B-2. Pseudomonas putida (ATC
Page 195 and 196: Appendix B-3. Calibration of Chemic
Page 197 and 198: Appendix B-4. Calibration of Toluen
Page 199 and 200: Appendix C. Experimental Results: A
Page 201: Probe response time, s 12 10 8 6 4
Page 205 and 206: Appendix D: Mathematical Solutions
Page 207 and 208: The microscopic model allows the fo
Page 209 and 210: 13δ Y o , = 0.585 2 x = (D-24) (8K
Page 211 and 212: 2 σ = −1.3E − 06 (E-11) Y xe Y
Page 213: Biomass, ethanol, and acetic acid c
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Experimental Study of Biodegradation of Ethanol and Toluene Vapors

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