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

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Table 2.12 Membrane Processes (Rautenbach and Albrecht, 1989) Membrane Mixtures Separated Driving Force Preferably Permeating Processes Component Reverse Aqueous low Pressure difference Solvent Osmosis molecular mass solutions, Aqueous organic solutions (≤ 100 bar) Ultrafiltration Macromolecular Pressure difference Solvent solutions, emulsions (≤ 10 bar) Microfiltration Suspensions, Pressure difference Continuous phase (cross flow) emulsions (≤ 5 bar) Gas Permeation Gas mixtures, Pressure difference Preferably permeating water-vapour gas mixtures (≤ 80 bar) component Pervaporation Organic mixtures, Permeate side: Ratio Preferably permeating aqueous organic of partial pressure to component mixtures saturation pressure Due to high rejection ability, reverse osmosis membranes retain both organic and inorganic contaminants dissolved in water with rejection rates of 98 to 99 % thus being useful for purifying of liquid waste such as leachate. Permeate generated from the reverse osmosis unit is low in inorganic and organic contaminants which meet the discharge standards. Reverse osmosis technology was reported as the most effective in COD removal among different physical-chemical processes evaluated. The removal efficiencies are dependent on the choice of membrane material. Chian and DeWalle (1976) reported 50 to 70 % removal of TOC with cellulose acetate membranes while the use of polyethylamine membranes increased efficiency to 88 %. Reverse osmosis further offers the advantage of almost complete total solid removal and is effective as either a pre-treatment or a polishing treatment for a biologically or ion exchange treated effluent. Membrane filtration is less effective in treating young or acidogenic leachate. The efficiency of different membrane technology in treating methanogenic leachate is presented in Table 2.13. Although nanofiltration and reverse osmosis are quite effective in leachate treatment in terms of organic, inorganic, nitrogen and AOX removal, the disadvantage of membrane treatment system is its susceptibility to fouling and short lifetime. Table 2.13 Removal Efficiency of Moderate to High Concentrations of Pollutants Using Nanofiltration, Ultrafiltration and Reverse Osmosis (Kylefors, 1997) Parameter Reverse Osmosis Nanofiltration Ultrafiltration Removal (%) Removal (%) Removal (%) COD 95 to 99 80 to 90 25 to 60 NH4(N), pH = 6.5 90 to 98 80 to 90 < 20 AOX 95 to 99 70 to 90 30 to 60 Chloride 90 to 99 40 to 90 < 40 28
Colloidal material as well as metal precipitation can cause fouling and clogging in the membranes. Fouling leads to an increase in osmotic pressure and hydraulic resistance, thus increasing the energy consumption. In order to minimize the fouling effect, the pH can be adjusted from 4 to 7.5. Since membranes cannot retain volatile fatty acids, acidogenic leachate is poorly treated using membrane systems. A coupling of a membrane and activated sludge process to form a membrane bioreactor may be more viable as the membrane ensures total solids retention. For moderate to strong methanogenic leachate, a good removal of several substances, including metals can be achieved using bioreactors. Hence, a combination of an activated sludge process with a membrane system, the membrane bioreactor technology can achieve high treatment efficiency with an excellent effluent quality. The application of reverse osmosis for large-scale application had been done in Germany. The process train is as shown in Figure 2.6. The reverse osmosis system had a capacity of 36m 3 /h and had been in operation for long with a change of a membrane after 8 years (Peters, 1997). Operational pressure was ranged from 36 to 60 bars depending on feed characteristics. Membrane filtration took place at ambient temperature and at a permeate flux of 15 L/m 2 .h. The performance of the plant is illustrated in Table 2.14. When a reverse osmosis in Germany was operated at a capacity of 1.8m 3 /h, a salt rejection of 98 % and COD removal of 99 % could be achieved. The membrane was changed after 3 years of operation due to the flux reduction. The illustrations indicated that reverse osmosis is effective in landfill leachate treatment provided that the leachate characteristic is considered and the membrane module modified adapted to meet the design criteria (Peters, 1997). Leachate Binding Reagents Reverse Osmosis I Reverse Osmosis II RO Permeate I Solidification of Residue Concentrate I Concentrate Stabilized Materials Figure 2.6 Treatment of Landfill Leacahte with Two Stage Reverse Osmosis (Peters, 1997) 29 Concentrate II (Recirculation to RO I) RO Permeate II
Page 1 and 2: APPLICATION OF MEMBRANE BIOREACTOR
Page 3 and 4: Abstract Landfill leachate is a com
Page 5 and 6: Table of Contents Chapter Title Pag
Page 7 and 8: 4.5.6 Cost Analysis for Operation 1
Page 9 and 10: 4.4 Effect of Free Ammonia Concentr
Page 11 and 12: 4.16 COD Concentration in the Influ
Page 13 and 14: MWCO Molecular Weight Cut-off MWW M
Page 15 and 16: 1.1 Background Chapter 1 Introducti
Page 17 and 18: generally unsuccessful in removal o
Page 19 and 20: 2.1 Introduction Chapter 2 Literatu
Page 21 and 22: In the municipal solid waste landfi
Page 23 and 24: COD/TOC, VS/FS and VFA/TOC ratios o
Page 25 and 26: Table 2.3 presents the general leac
Page 27 and 28: Ground water 2.7.1 Seasonal Variati
Page 29 and 30: 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: Activated Carbon Adsorption Granula
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 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
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Though, the obtained COD removal ef
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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
Page 157 and 158:
Raw Leachate YMBR Effluent BMBR Eff
Page 159 and 160:
Appendix B Leachate Characteristics
Page 161 and 162:
Table B-2 Acclimation of Mixed Yeas
Page 163 and 164:
Appendix C Experimental Data of Bio
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y: Where: OUR at line g: This is th
Page 167 and 168:
Table C-3 Experimental Results for
Page 169 and 170:
Appendix D Membrane Resistance Stud
Page 171 and 172:
Table D-3 Experimental Data for Det
Page 173 and 174:
Table D-4 Experimental Data for Det
Page 175 and 176:
Pressure (kPa) Pressure (kPa) 25 20
Page 177 and 178:
Appendix E MBR without Ammonia Stri
Page 179 and 180:
Day HRT (h) pH COD (mg/L) Feed Reac
Page 181 and 182:
Day HRT (h) pH COD (mg/L) Feed Reac
Page 183 and 184:
Table E-3 Variation in TMP with Tim
Page 185 and 186:
Appendix F Ammonia Stripping Studie
Page 187 and 188:
Table F-5 Pilot Scale Study on Ammo
Page 189 and 190:
Table G-1 Feed, Reactor and Effluen
Page 191 and 192:
Table G-3 Feed, Reactor and Effluen
Page 193 and 194:
Appendix H Other Studies 179
Page 195 and 196:
Table H-2 Membrane Resistance of th
Page 197:
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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