Experimental Study of Biodegradation of Ethanol and Toluene Vapors

More documents

Recommendations

Info

• At an inlet air concentration of 19.5 mg/L, ethanol was consumed 100% at maximum removal rates of 304 mg/L-h, which is better than existing biofilter systems currently in use by industry. • Steady state removal of ethanol-toluene mixture from a contaminated air stream was conducted using a CSTR. The removal efficiency reached 100% for ethanol and 89% for toluene at ethanol inlet concentration of 15.9 mg/L and toluene inlet concentration of 4.5 mg/L. The fastest toluene removal rate was 93 mg/L-h. • Using benzyl alcohol as the co-substrate, toluene was again successively removed from a contaminated air stream using a CSTR. The removal efficiency of toluene reached 97% with the fastest toluene removal rate of 93 mg/L-h. The metabolic models were developed for bioremediation of ethanol/benzyl alcohol based on the published metabolic pathways. Specific discoveries from metabolic modeling are: • Simple Monod and substrate inhibition kinetics generated curves that were able to represent the experimental batch biodegradation of ethanol and benzyl alcohol, respectively, within 95% confidence level. The metabolic model then allowed the incorporation of these kinetic coefficients to predict the in-situ concentrations of other key metabolites (ATP, CO 2 , etc.) during batch growth cultures. • The metabolic models have also been developed to simulate simultaneous bioremediation of ethanol / toluene and benzyl alcohol/toluene mixtures. 154
Toluene acts as an inhibitor on the growth of P. putida on these mixtures, and does not contribute to increased growth rates or biomass production. • For continuous steady state operations, the more readily degradable substrate, ethanol, requires less maintenance for biomass growth on its own (0.10 C- mol/C-mol-h) than bioremediation in the presence of toluene, such as bioremediation of ethanol/toluene mixture (0.27 C-mol/C-mol-h), and benzyl alcohol/toluene mixture (0.069 C-mol/C-mol-h). • When biomass concentrations reach high levels, the oxygen demand will also be high, which can limit growth, and may require an oxygen enriched air supply. 6.2 RECOMMENDATIONS • More thorough chemical analyses of the cultures, including ATP, CO 2 , acetic acid, etc., is recommended to provide more data for fitting the metabolic models. • More CSTR experiments at wider operating conditions are recommended. In particular, the lowering of the concentrations of the co-substrates should be studied in the hopes that higher amounts of toluene can be captured and bioremediated. • A wider range of VOCs should be investigated in order to determine the minimum water solubility chemicals that can actively be consumed by Psuedomonas putida. • A wider range of bacteria should be investigated to determine if bioremediation of toluene as a sole substrate could be achieved in a CSTR. 155
Page 1 and 2:
BIOREMEDIATION OF VOLATILE ORGANIC
Page 3 and 4:
ABSTRACT The mass transfer of ethan
Page 5 and 6:
effect on the growth of P. putida.
Page 7 and 8:
ACKNOWLEDGMENT Of the countless peo
Page 9 and 10:
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 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 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 (
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
Page 129 and 130: x = 5 ∑ i= 1 x N i (5-40) where x
Page 131 and 132: ethanol in a steady state mode is l
Page 133 and 134: where ν 1 , ν 2 , ν 3, ν 4 are
Page 135 and 136: Biomass concentration, g/L 1.5 1 0.
Page 137 and 138: φ T =ν 4 (5-53b) φx = −ν 1 (5
Page 139 and 140: In this study, a metabolic model ha
Page 141 and 142: Equations (5-34) and (5-35) and the
Page 143 and 144: ATP 1 = Y max ATP r x + m ATP ⋅ C
Page 145 and 146: Ethanol, biomass and ammonium conce
Page 147 and 148: Figure 5-13a shows that the lower t
Page 149 and 150: 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: • Air stripping coefficients obta
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 and 202: Probe response time, s 12 10 8 6 4
Page 203 and 204: Appendix C-2. Fed-batch Operation B
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
show all

Experimental Study of Biodegradation of Ethanol and Toluene Vapors

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?