Experimental Study of Biodegradation of Ethanol and Toluene Vapors

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3.4.3 Batch Growth The batch growth experiments were carried out to study the growth rates of P. putida (ATCC 23973) on different substrates, however toluene was stripped too quickly from the bioreactor to carry out batch growth experiments (Brown et al., 2000). Therefore, bioremediation kinetics on ethanol or benzyl alcohol was determined from batch growth experiments. A volume of 1.5 L of media was added to the bioreactor. The reactor, complete with the nutrient media, was sterilized at a temperature of 121 o C for 45 minutes. The inoculum was prepared in shaking flasks using the same chemical as the growth substrate (see Section 3.2.3 for preparation procedure). A certain amount of the selected substrate was added into the bioreactor to reach the desired initial concentration then 75-150 mL of inoculum was aseptically transferred from the shake flask into the bioreactor. The media in the bioreactor thus contained either ethanol or benzyl alcohol at known initial concentrations. The temperature was controlled at 25.0 °C. In order to maintain efficient mixing in the reactor, and to gain sufficient oxygen supply from the air stream, an agitation rate of 450 rpm and an air flowrate of 0.4 L/min was set for all experiments. These operating conditions were based on the results from air stripping and mass transfer experiments. Samples of approximately 10 mL were taken at specific time intervals through the liquid sample port. Three to four mililitres of these samples were immediately analyzed for biomass concentration, and a 5 mL sample was 42
centrifuged and the supernatant was then analyzed for substrate concentration by GC analyses. Samples were always collected and analyzed in duplicate. 3.4.4 Continuous Bioremediation in a CSTR In these experiments, sterilized nutrient media was continuously fed to the bioreactor and spent fermentation broth was continuously removed at dilution rates of 0.01 to 0.1 h -1 . The organic food source was provided from the contaminated air stream. Contaminated air, containing ethanol, toluene or mixtures of ethanol and toluene at various concentrations, was bubbled into the bioreactor using varying flow rates while the agitation speed and temperature were held at 450 rpm and 25.0 °C. 43
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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
Page 11 and 12: 4.3 Batch Growth on Ethanol and Ben
Page 13 and 14: LIST OF FIGURES Figure 3-1. Schemat
Page 15 and 16: Figure 5.3 (b) Simulation of ethano
Page 17 and 18: Figure 5-16. Continuous removal of
Page 19 and 20: NOMENCLATURE a - Interfacial area,
Page 21 and 22: CHAPTER ONE - INTRODUCTION 1.1 Air
Page 23 and 24: esults (van Groenestijn and Hesseli
Page 25 and 26: experimental results are presented
Page 27 and 28: Table 2.2 VOC Emissions in the U.S.
Page 29 and 30: (paint shop effluents, for instance
Page 31 and 32: combustion provides 70 to 90% air p
Page 33 and 34: used to degrade ethanol vapours and
Page 35 and 36: g m -3 . This would suggest that th
Page 37 and 38: treatment, This excessive biomass f
Page 39 and 40: The simultaneous degradation of tol
Page 41 and 42: emoves only water-soluble gases. Wa
Page 43 and 44: 2.2.6 Pseudomonas It is well known
Page 45 and 46: 2.3.2 Growth Models with Inhibition
Page 47 and 48: where µ is the total specific grow
Page 49 and 50: 2.4.1 Batch Reactor In a batch reac
Page 51 and 52: discharged from the other end. The
Page 53 and 54: element solution consisted of (gram
Page 55 and 56: growth on ethanol, 20-48 hours for
Page 57 and 58: Gas phase samples of toluene were c
Page 59 and 60: Inlet sampler Exit sampler To fume
Page 61: Once the oxygen meter indicated a s
Page 65 and 66: where k L a is the volumetric mass
Page 67 and 68: Figure 4-2a shows ethanol liquid co
Page 69 and 70: coefficient (k L a) in the well-mix
Page 71 and 72: calculated by dividing the gas volu
Page 73 and 74: Average bubble diameter, mm 8 7 6 5
Page 75 and 76: Bioflow III bioreactor. Equation (4
Page 77 and 78: 3.5 y=Ln(S0/S) 3 2.5 2 1.5 1 y = 12
Page 79 and 80: Ethanol and biomass concentration,
Page 81 and 82: 4.3.2 Batch Growth on Benzyl Alcoho
Page 83 and 84: Biomass and benzyl alcohol concentr
Page 85 and 86: ethanol loading was beyond the maxi
Page 87 and 88: Table 4-2. Comparison of bioremedia
Page 89 and 90: Biomass, benzyl alcohol and toluene
Page 91 and 92: 4.4.3 Toluene-ethanol Bioremediatio
Page 93 and 94: Substrate and biomass concentration
Page 95 and 96: Biomass and benzyl alcohol concentr
Page 97 and 98: Biomass and benzoic acid concentrat
Page 99 and 100: ethanol. These results clearly indi
Page 101 and 102: CHAPTER FIVE - MATHEMATICAL MODELIN
Page 103 and 104: The stoichiometry of the biomass sy
Page 105 and 106: synthesis and in the ethanol catabo
Page 107 and 108: 1 max Y ex = − 0.635 + 2δ + K 3
Page 109 and 110: Biomass Eq.5-18 Benzyl Alcohol Eq.5
Page 111 and 112: 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,
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C e DKe = (5-63) μ − D m Equatio
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corresponds with the value associat
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Biomass and ethanol concentrations
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than 4.0 mg/L at all dilution rates
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Biomass, benzyl alcohol and ammonia
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negligible ( y out , e = 0) , and e
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Figure 5-17 shows the results at a
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Biomass Concentrations, g/L 3.5 3 2
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C x ( 1 max Q max = ⋅{ D( Cb0 −
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1.2 g/L, the system could not be op
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The continuous models can capture a
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• Air stripping coefficients obta
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Toluene acts as an inhibitor on the
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Bruining, W. J., G. E. H. Joosten,
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Falatko, D. M., and J. T. Novak, 19
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Keuning, S., and D. Jager, 1994.
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Orshansky, F., and N. Narkis, 1997.
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Togna, A. P, M. Singh, 1994. “Bio
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APPENDIX A. Important Metabolic Pat
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III. Toluene Pathway (Adapted from
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Appendix B. Calibration Procedure a
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Figure B-2. Pseudomonas putida (ATC
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Appendix B-3. Calibration of Chemic
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Appendix B-4. Calibration of Toluen
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Appendix C. Experimental Results: A
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Probe response time, s 12 10 8 6 4
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Appendix C-2. Fed-batch Operation B
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Appendix D: Mathematical Solutions
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The microscopic model allows the fo
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13δ Y o , = 0.585 2 x = (D-24) (8K
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2 σ = −1.3E − 06 (E-11) Y xe Y
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Biomass, ethanol, and acetic acid c
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Experimental Study of Biodegradation of Ethanol and Toluene Vapors

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