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

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available, and appears to be cost effective pretreatment option for landfill leachate (Cheung, et al., 1997), it was used in the present studies. The initial ammoniacal nitrogen in the simulated landfill leachate proposed in the study was around 1,600-1,800 mg/L. Ammonia stripping studies were done in two stages- one in the laboratory scale to optimize the parameters to be used for ammonia studies prior to MBR process and secondly, in the pilot scale studies to confirm the results of the laboratory studies in a larger scale. The laboratory scale studies were done with leachate volume of 2 L whereas pilot scale studies were done with leachate volume of 40 L. Firstly, the pH for the ammonia stripping was standardized using a velocity gradient of 1,530 s -1 with a contact time of 2 h. The alkaline pH facilitates the formation of the free ammonia molecule in comparison with the ammonium ion, thus making it easy to remove ammonia. For this reason, the pH was adjusted to alkaline condition. The pH was adjusted to 9, 10, 11, and 12 using sodium hydroxide solution. The variation in removal efficiency was tested for three samples with different concentrations to eliminate the standard error in the analysis. It was found that the ammonia removal efficiency significantly increased when pH was increased from 10 to 11 or 12. The detailed results are presented in Table F-1 of Appendix F. The removal efficiency was 38-45 % at pH 11 compared to 16-23% at pH 9 and 24-30% at pH 10 (Figure 4.21). The difference between the removal efficiency at pH 11 and 12 was around 5%, which was considered not much significant. Thus, it could be said that the effective pH for the ammonia stripping would be around 11-12. The results of ammonia stripping were similar to other studies done in municipal landfill leachate (Cheung, et al., 1997; Ozturk, et al., 1999). After standardization of pH, the velocity gradient and the contact time were standardized using leachate samples with pH 11-12. The ammonia concentration and removal efficiency at different contact time and the velocity gradients are given in the Table F-2 to F-4 of Appendix F. The contact time for the ammonia removal was varied from 2 to 6 h. The velocity gradient used in the study was 1,530, 2,850 and 4,330 s -1 , which were varied along with the contact time. Figure 4.22 elaborates the removal efficiency and ammonia concentration with varying contact time and velocity gradient for the initial leachate ammonia concentration of 1, 380 mg/L. The summary of the results for different samples at varied contact time and velocity gradient is summarized in Table 4.12. The rate of ammonia removal is directly proportional to the velocity gradient or the volume of air diffused through the liquid. The main mechanism used for ammonia removal was simple mechanical mixing. It was found that when the velocity gradient was increased from 2,850 s -1 to 4,330 s -1 , the removal efficiency did not improve much with 2, 4 and 6 h contact time. Therefore, it could be concluded that 2,850 s -1 was the optimum velocity gradient for ammonia stripping. The ammonia removal efficiency was found to be between 88 and 95% at 4 h contact time at velocity gradient of 2,850 s -1 . Though at 6 h contact time, the ammonia removal efficiency improved further, the difference in ammonia removal between 4 and 6 h was not significant. Thus, the standard velocity gradient and the contact time were taken as 2,850 s -1 and 4 h, respectively. At optimum conditions, the system consumed NaOH of 12.5 kg/m 3 and produced sludge at a rate of 80-100 L/m 3 . 92
Ammonia Concentration (mg/L) Ammonia Removal (%) 1600 1400 1200 1000 Figure 4.21 Variation in the Ammonia Removal Efficiency with pH 800 600 400 200 0 60 50 40 30 20 10 0 1,106 mg/L 1,366 mg/L 1,380 mg/L 0 1 2 3 Contact Time (h) 4 5 6 Figure 4.22 Ammonia Removal Efficiency with Varying Velocity Gradient and pH 93 R 2 = 0.9753 8 9 10 11 12 13 pH 100 90 80 70 60 50 40 30 20 10 0 Control 1530 s-1 2850 s-1 4330 s-1 Removal Effeciency (%)
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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
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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
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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
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Table 2.10 Treatment Efficiencies o
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Activated Carbon Adsorption Granula
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Colloidal material as well as metal
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iologically, physical-chemical proc
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Ammonia Stripping Air stripping of
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These systems are land intensive wh
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the biological treatment can be rep
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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 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: The probable reason for frequent fo
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
Page 141 and 142: Diamadopoulos, E., 1994. Characteri
Page 143 and 144: Grady, C.P.L., Daigger, G.T., and L
Page 145 and 146: Keenan, J.D., Steiner, R.L., and Fu
Page 147 and 148: Martin, G.M.A., Auzmenti, A.I., and
Page 149 and 150: Pohland, F.G., and Harper, S.R., 19
Page 151 and 152: Shin, H.S., An, H., Kang, S.T., Cho
Page 153 and 154: Visvanathan, C., Ben Aim, R., and P
Page 155 and 156: 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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