Experimental Study of Biodegradation of Ethanol and Toluene Vapors

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4.3 Batch Growth on Ethanol and Benzyl Alcohol 4.3.1 Batch Growth on Ethanol One of the ethanol batch growth experiments is shown in Figure 4-7 (S 0 = 2.3 g/L). Growth started after a 5 h lag phase and was reflected exactly by ethanol consumption in the bioreactor. The initial concentration of 2.3 g/L of ethanol was completely consumed in less than 12 hours. At low initial ethanol concentrations no byproduct was detected in the media and the Monod model was used to describe the growth kinetics: 1 dX μ S μ = = max X dt K + (4-9) s S μ max is the maximum specific growth rate and K s is the Monod saturation constant. The specific growth rate on ethanol during the log phase was determined by plotting ln(X) versus time. The dissolved oxygen values were found to be higher than the critical value (0.35 mg/L, Shuler and Kargi, 2002) for growth on ethanol at initial concentrations up to 5.8 g/L, which indicated that oxygen mass transfer is not a ratelimiting step under these conditions. For the batch growth experiments at ethanol initial concentrations up to 5.8 g/L, the specific growth rates were within the range of 0.37 ± 0.03h -1 . This rate of growth on ethanol is much greater than the maximum specific growth rate (0.046 h -1 ) of Acetobacter aceti on ethanol reported earlier by Wei et al., 1999. Pseudomonas putida (ATCC 23973) will therefore be much more effective in removing ethanol from contaminated air compared to that earlier work. The growth process is reproducible, and Figure 4-8 shows the results for two different batch runs. 58
Ethanol and biomass concentration, g/L 2.5 2 1.5 1 0.5 0 biomass ethanol 0 5 10 15 Time, h Figure 4-7. Batch growth of Pseudomonas putida on ethanol at initial concentration of 2.3 g/L, air flow rate of 0.4 L/min, 450 rpm and 25.0 o C 59
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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
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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
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 and 62: Once the oxygen meter indicated a s
Page 63 and 64: centrifuged and the supernatant was
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: 3.5 y=Ln(S0/S) 3 2.5 2 1.5 1 y = 12
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
Page 113 and 114: φ = −θ b ⋅ν (5-31) φ b = 1.
Page 115 and 116: The data sets used to evaluate the
Page 117 and 118: Figures 5.4a and 5.4b present 95% c
Page 119 and 120: Ethanol and biomass concentration (
Page 121 and 122: Ethanol measured (C-mol/L) 0.3 0.25
Page 123 and 124: Figures 5.5 (a-d) demonstrate the s
Page 125 and 126: Benzyl alcohol and biomass concentr
Page 127 and 128: 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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