Experimental Study of Biodegradation of Ethanol and Toluene Vapors

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kLa, s -1 0.1 0.08 0.06 0.04 0.02 0 Water 1 g/L ethanol 3 g/L ethanol 8 g/L ethanol 0 200 400 600 800 Impeller speed, rpm Figure 4-3. Effects of ethanol concentration and impeller speed on oxygen mass transfer coefficients (error bars are standard deviations) compared to increases of 2.4 times observed by Benedek and Heideger (1971) using 11.7 g/L of sodium chloride. Voigt and Schugerl (1979) reported that k L a increased by a factor of three with ethanol addition in a bubble column. The overall oxygen transfer coefficient increases with increasing impeller speed over the range of 135 to 600 rpm as shown in Figure 4-3. This trend agrees with k L a measurements in stirred tanks reported by others (Benedek and Heideger, 1971; Robinson and Wilke, 1973, 1974; Hassan and Robinson, 1980). The gas holdup was also measured for each operating condition. After the bioreactor was filled initially with the ethanol solution, the gas volume was determined by measuring the amount of liquid that overflowed with the introduction of air at a constant flow rate of 3.5 L/min at each impeller speed. The gas holdup was then 50
calculated by dividing the gas volume by total bioreactor volume, and the results are given in Table 4-1. The experimental data show that the gas holdup increases with increasing ethanol concentration and with increasing impeller speed. Table 4-1. Gas Holdup Gas holdup (ε, %) 135 rpm 300 rpm 450 rpm 600 rpm Distilled Water 1.76 2.49 2.96 3.51 1 g/L Ethanol Solution 1.78 2.48 3.42 4.76 3 g/L Ethanol Solution 1.82 2.54 3.56 5.35 8 g/L Ethanol Solution 1.85 2.66 3.77 5.91 20 g/L Ethanol Solution - - - 7.76 Determination of Average Bubble Diameter The interfacial area, a in Equation (4-4), can be calculated from the experimental data of k L a using a constant k L value of 0.000135 m/s in distilled water (Calderbank and Moo-Young, 1961). The other parameter needed to evaluate bubble diameter is gas holdup. The increase in gas holdup is due to the decrease in surface tension, which was measured with a Du Noüy ring – tensiometer (model K10ST, Tekmar Company). The surface tension was determined to be 71.7, 71.4, 70.2 and 67.7 mN/m for ethanol concentrations in distilled water of 0, 1, 3, and 8 g/L, respectively. With gas holdup data measured, the average bubble diameter can then be calculated from (Hill et al., 1996): d b × ε = 6 (4-5) a 51
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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
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 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: coefficient (k L a) in the well-mix
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
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 (
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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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