Thesis - faculty.ait.ac.th - Asian Institute of Technology

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4.2 Biokinetic Studies Bio-kinetic experiments are important in any biological treatment systems. A biological system consists of a mixture of organisms with different growth patterns and degradation rates. The overall growth and degradation rate is important for the degradation of the pollutants present in the waste. Therefore, bio-kinetic studies were conducted to get an overall picture of the degradation potential and growth of the microorganisms used in the degradation pattern. 4.2.1 Acclimatization of Mixed Yeast and Bacterial Sludge Prior to the biokinetic study, it is necessary to acclimatize the organisms to the prevailing toxic conditions of the leachate having high COD and ammonia concentrations along with other humic organic components. After acclimatization of the culture to be used, a rich mixture of resistant leachate degrading organisms could be obtained. In the present experiment, bacterial and yeast culture were used to degrade the leachate in the membrane bioreactors. Preceding acclimatization of the yeast culture, to obtain a wide range of the yeast species, yeast was enriched using the standard enrichment technique. The enrichment was completely accomplished once the yeast reached a MLSS concentration of 3,000 mg/L. The acclimatization and the enrichment of the bacterial and yeast culture was done as described in section 3.3.2. The pH of the yeast culture was maintained at around 3.5 as yeast activity is pronounced at low pH and this would also help in preventing bacterial contamination. (1) Organic Removal The acclimatization of the bacterial and yeast culture were done as described in section 3.3.2 with the simulated medium-aged landfill leachate having characteristic given in section 3.2 with variation in COD load, which was step-wise increased to finally obtain an acclimatized culture. The operation conditions for the acclimatization process are mentioned in the Table 3.2. The organic load while acclimatizing was step wise increased from 3,800 to 7,300 for bacterial as well as yeast culture. The acclimatization was done step-wise until a COD removal approximately 70% could be achieved. The changes in the biomass concentration along with the F/M ratio and COD removal efficiencies were noticed. These measured parameters are given in Table B-2 and B-3 of Appendix B. Acclimatization of yeast and bacterial culture took about 67 days. The change in the COD removal efficiency and the F/M ratio is given in Figure 4.1 and 4.2. It was found that after 67 days, the COD removal efficiency with yeast culture was higher than that of bacterial culture. The COD removal efficiency reached 75% in yeast sludge compared to 66% in the bacterial sludge. This indicates that, yeast culture could probably be more effective in leachate treatment than the bacterial culture. However, as the results obtained are not sufficient to conclude that yeast system has a better performance than bacteria system, further investigation is necessary. F/M ratio decreased from 1.01 to 0.62 kg COD/kg SS.d in the yeast culture and from 1.45 to 1.14 kg COD/kg SS.d in the bacterial sludge. The difference between the F/M ratios in the bacterial culture was not as much as the yeast culture. This suggests that the growth of the yeast culture was more prominent than the bacterial culture. Lower the F/M ratio, the better is the leachate treatment capacity of the system. This could be the reason for the better removal efficiency of COD by the yeast culture. 68
COD Removal Effeciency (%) COD Removal Effeciency (%) . 80 70 60 50 40 80 70 60 50 40 0 10 20 30 40 50 60 70 80 Time (Days) Figure 4.1 Variation in F/M and COD Removal Efficiency in Yeast Sludge Figure 4.2 Variation in F/M and COD Removal Efficiency in Bacterial Sludge 69 COD Removal Effeciency F/M Ratio COD Removal Effeciency F/M Ratio 0 10 20 30 40 50 60 70 80 Time (Days) 1.60 1.40 1.20 1.00 0.80 0.60 0.40 1.60 1.40 1.20 1.00 0.80 0.60 0.40 F/M (kgCOD/kg SS.d) F/M (kgCOD/kg SS.d)
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APPLICATION OF MEMBRANE BIOREACTOR
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Abstract Landfill leachate is a com
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Table of Contents Chapter Title Pag
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4.5.6 Cost Analysis for Operation 1
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4.4 Effect of Free Ammonia Concentr
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4.16 COD Concentration in the Influ
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MWCO Molecular Weight Cut-off MWW M
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1.1 Background Chapter 1 Introducti
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generally unsuccessful in removal o
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2.1 Introduction Chapter 2 Literatu
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In the municipal solid waste landfi
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COD/TOC, VS/FS and VFA/TOC ratios o
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Table 2.3 presents the general leac
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Ground water 2.7.1 Seasonal Variati
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Table 2.5 Variation of COD, BOD & B
Page 31 and 32: entails the re-circulation of leach
Page 33 and 34: Table 2.8 Summary of Biokinetic Coe
Page 35 and 36: that extensive loss of nitrogen (up
Page 37 and 38: ammonia could only be achieved when
Page 39 and 40: Table 2.10 Treatment Efficiencies o
Page 41 and 42: Activated Carbon Adsorption Granula
Page 43 and 44: Colloidal material as well as metal
Page 45 and 46: iologically, physical-chemical proc
Page 47 and 48: Ammonia Stripping Air stripping of
Page 49 and 50: These systems are land intensive wh
Page 51 and 52: the biological treatment can be rep
Page 53 and 54: Table 2.16 Typical Leachate Composi
Page 55 and 56: influent reached 200 mg/L. For the
Page 57 and 58: Table 2.18 Advantages and Disadvant
Page 59 and 60: through the effluent. Different ope
Page 61 and 62: Mixed Liquor Suspended Solids and D
Page 63 and 64: 2.12 Yeasts 2.12.1 Introduction The
Page 65 and 66: Nishihara ESRC Ltd. (2001) studied
Page 67 and 68: nitrification-denitrification proce
Page 69 and 70: Table 3.1 Composition of Simulated
Page 71 and 72: 3.4.1 Ammonia Toxicity The experime
Page 73 and 74: Figure 3.4 Experiments Conducted to
Page 75 and 76: Leachate Option Ammonia Stripping R
Page 77 and 78: MW larger than 50 kDa, (2) MW betwe
Page 79 and 80: Figure 3.7 Flowchart Showing Ammoni
Page 81: Chapter 4 Results and Discussion 4.
Page 85 and 86: MLSS (mg/L) 14000 12000 10000 8000
Page 87 and 88: Specific Growth Rate ( d -1 ) 0.50
Page 89 and 90: change in the predominant species w
Page 91 and 92: Table 4.4 Effect of Free Ammonia Co
Page 93 and 94: Table 4.5 Substrate Utilization by
Page 95 and 96: 4.3.1 Initial Membrane Resistance P
Page 97 and 98: when compared with the present stud
Page 99 and 100: COD Removal Efficiency (%) 90 80 70
Page 101 and 102: (2) TKN Removal Efficiency Prior to
Page 103 and 104: As there was no significant improve
Page 105 and 106: The probable reason for frequent fo
Page 107 and 108: Ammonia Concentration (mg/L) Ammoni
Page 109 and 110: concentration after treatment. Othe
Page 111 and 112: After the chemical cleaning of the
Page 113 and 114: emoval of 38%. A higher removal in
Page 115 and 116: Influent BOD (mg/L) Influent BOD (m
Page 117 and 118: (3) TKN Removal Efficiency The TKN
Page 119 and 120: Figure 4.34 gives the overall TKN r
Page 121 and 122: fraction and slowly biodegradable C
Page 123 and 124: BOD (mg/L) BOD (mg/L) 6000 5000 400
Page 125 and 126: Figure 4.39 Molecular Weight Cut-of
Page 127 and 128: COD (mg/L) 8000 6000 4000 2000 COD
Page 129 and 130: Though, the obtained COD removal ef
Page 131 and 132: cake used on the top of the membran
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Chapter 5 Conclusions and Recommend
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0.02, respectively. This can be con
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References Abeling, U., and Seyfrie
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Brown, M.J., and Lester, J.N., 1980
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Diamadopoulos, E., 1994. Characteri
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Grady, C.P.L., Daigger, G.T., and L
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Keenan, J.D., Steiner, R.L., and Fu
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Martin, G.M.A., Auzmenti, A.I., and
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Pohland, F.G., and Harper, S.R., 19
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Shin, H.S., An, H., Kang, S.T., Cho
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Visvanathan, C., Ben Aim, R., and P
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Appendix A Pictures of Experiments
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Raw Leachate YMBR Effluent BMBR Eff
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Appendix B Leachate Characteristics
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Table B-2 Acclimation of Mixed Yeas
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Appendix C Experimental Data of Bio
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y: Where: OUR at line g: This is th
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Table C-3 Experimental Results for
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Appendix D Membrane Resistance Stud
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Table D-3 Experimental Data for Det
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Table D-4 Experimental Data for Det
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Pressure (kPa) Pressure (kPa) 25 20
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Appendix E MBR without Ammonia Stri
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Day HRT (h) pH COD (mg/L) Feed Reac
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Day HRT (h) pH COD (mg/L) Feed Reac
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Table E-3 Variation in TMP with Tim
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Appendix F Ammonia Stripping Studie
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Table F-5 Pilot Scale Study on Ammo
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Table G-1 Feed, Reactor and Effluen
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Table G-3 Feed, Reactor and Effluen
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Appendix H Other Studies 179
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Table H-2 Membrane Resistance of th
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Table H-6 Chemical Cost for the Yea
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Thesis - faculty.ait.ac.th - Asian Institute of Technology

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