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

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that the nitrifying bacteria are more sensitively inhibited by a given concentration of chemical toxicant than the heterotrophic bacteria. Thus, failure of the nitrifying process would occur before the carbonaceous removal process. Blum and Speece (1992) also reported that Nitrobactor exhibited approximately the same toxicity as aerobic heterotrophs. Thus, to prevent the interference of the nitrifying system in the toxicity test, 70 mg/L of Nitrogen as NH3-N was added to suppress nitrification (Liebeskind, 1999) in the bacterial system. The major biokinetic parameters found in the two systems namely, the bacterial and yeast sludge are expressed in Table 4.3 and 4.4, respectively. The concentration of free ammonia produced in the system was also measured using a dissociation equation of ammonium salt into ammonia and hydrogen ion (Ortiz, et al., 1997). The formulae used for measuring the free ammonia in given below: [NH3-N] = 17 [NH4 + -N] 10 pH Eq. 4.1 14 exp [ 6344 / ( 273 + T ) ] + 10 pH The inhibition was found to be much higher in the bacterial sludge than that of the yeast sludge. The probable reason for this could be the low oxygen uptake of 0.0030 mg O2/mg VSS. h compared to that 0.0078 mg O2/mg VSS. h of the bacterial culture even at an ammonium chloride concentration of 70 mg/L. The complete biokinetic parameters measured for the yeast and bacterial system are presented in Table C-3 and C-4 of Appendix C. The free ammonia nitrogen concentration in the bacterial sludge was found to reach a maximum of 20 mg/L whereas that found in yeast sludge was 0.013 mg/L. It has been found that the ammonia concentration of 31 to 49 mg/L can cause toxicity (Cheung, et al., 1997) and at a concentration of 200 mg/L can adversely affects the sludge properties (Robinson and Maris, 1985). The toxicity of the compound also depends upon the nature and the composition of the waste. This could be the reason for relatively high toxicity of the ammonia in the landfill leachate. In a yeast based biological system, it was found that a free ammonia concentration of 11 mg/L would inhibit the growth of Candida utilis where the ammonium nitrogen concentration was 350- 520 mg/L (Ortiz, et al., 1997). Relatively low toxicity in the leachate studies could be attributed to the low pH. Table 4.3 Effect of Free Ammonia Concentration on Yield Coefficient and the Specific Growth Rate of the Bacterial Sludge NH4Cl (mg NH4-N/L) Free NH3 (mg NH3-N/L) Y (mg VSS/mg COD) µ (d -1 ) 70 0.44-0.70 0.39 0.093 1000 6.36-10.05 0.38 0.055 1500 9.54-15.07 0.35 0.046 2000 12.72-20.10 0.29 0.031 76
Table 4.4 Effect of Free Ammonia Concentration on Yield Coefficient and the Specific Growth Rate of the Yeast Sludge NH4Cl (mg NH4-N/L) Free NH3 (mg NH3-N/L) Y (mg VSS/mg COD) µ (d -1 ) 70 0 0.50 0.095 1000 0.003-0.006 0.49 0.089 1500 0.005-0.010 0.48 0.087 2000 0.006-0.013 0.49 0.090 The inhibition of the bacterial and the yeast culture with increasing concentration is expressed in Figure 4.9. The inhibition of the bacterial culture increased from 27 to 37% with corresponding increase in ammonium chloride concentration from 1,000 to 2,000 mg/L. The inhibition of the yeast culture was found to be around 6% even at an ammonium chloride concentration of 2,000 mg/L. % Inhibition 100 80 60 40 20 0 Mixed bacteria Mixed yeast R 2 = 0.9592 Figure 4.9 Inhibition of the Yeast and Bacterial Culture with Increasing Ammonium Chloride Concentration Another reason that would contribute to the resistance of the yeast sludge to the ammonia toxicity could be the ammonium and free ammonia concentration. It is well known that the molecular ammonia is toxic but not the ammonium ion. The relationship between the ammonium ion and ammonia is pH dependent. The ammonium ion in the wastewater is usually is in equilibrium with the ammonia and hydrogen ion concentration. The equation of which is expressed as follows: 77 R 2 = 0.9546 0 500 1000 1500 2000 2500 3000 3500 NH4Cl Concentration (mg/L)
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APPLICATION OF MEMBRANE BIOREACTOR
Page 3 and 4:
Abstract Landfill leachate is a com
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Table of Contents Chapter Title Pag
Page 7 and 8:
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
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entails the re-circulation of leach
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Table 2.8 Summary of Biokinetic Coe
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that extensive loss of nitrogen (up
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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 and 82: Chapter 4 Results and Discussion 4.
Page 83 and 84: COD Removal Effeciency (%) COD Remo
Page 85 and 86: MLSS (mg/L) 14000 12000 10000 8000
Page 87 and 88: Specific Growth Rate ( d -1 ) 0.50
Page 89: change in the predominant species w
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
Page 133 and 134: Chapter 5 Conclusions and Recommend
Page 135 and 136: 0.02, respectively. This can be con
Page 137 and 138: References Abeling, U., and Seyfrie
Page 139 and 140: 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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