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

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Table 2.4 Classification of Types of Substances Using Molecular Weight Cutoff (Chian, 1977; Harmsen, 1983) Division Molecular Weight Substances MW 10,000 Da High Molecular Weight Carbohydrates, Proteins Humic carbohydrate-like substances Thurman and Malcolm (1981) reported humic substances (hydrophobic acids) accounted for about 50 to 90 % of the dissolved organic carbon (DOC) present in leachate, whereas Imai, et al. (1995) indicated that humic substances contributed to only 30 % of the DOC. This implies that non-humic substances (hydrophobic neutrals and bases, hydrophilic acids, neutrals and bases) may be more important than humic substances in terms of refractory characteristics of leachate. The effectiveness of a treatment process can be related to the removal of specific organic fraction in leachate. Both fulvic and humic substances are inert to biological treatment. The accumulation of high molecular humic carbohydrates were found to affect bacteria flocculation (Chian and DeWalle, 1976). Therefore, fractionating the organic based on molecular weight, is an indication of the removal efficiency and degradation potential of the biological system. Generally, leachate is highly contaminated with organic concentrations measured as BOD and COD, with ammonia, halogenated hydrocarbons and heavy metals. The humic substances constitute an important group of organic matter in leachate (Chain, 1977; Lecoupannce, 1999). These substances can be compared with humic substances of natural organic matter (NOM). Humic substances are refractory anionic macromolecules of medium MW (1,000 Da MW- fluvic acids) to high MW (10,000 Da MW-humic acids). They contain both aromatic and aliphatic components with primarily carboxylic and phenolic functional groups. In many case, 500 to 1,000 Da MW fluvic-like fraction increases with landfill ages and after a biological treatment (Mejbri, et al., 1995). Therefore, a post treatment step is usually required for complete removal of organics (Rautenbach and Mellis, 1994). 2.7 Factors Affecting Leachate Composition In order to arrive at an appropriate treatment process, it is necessary to understand the leachate characteristic and the factors affecting it. Generally, the quantity of leachate is a direct function of the amount of external water entering the landfill. Landfill leachate is composed of the liquid that has entered the landfill from external sources, such as surface drainage, rainfall, groundwater and the liquid produced from the decomposition of waste. A generalised pattern of leachate formation is presented in Figure 2.4.
Ground water 2.7.1 Seasonal Variation Precipitation Evaporation Evaporation Surface runoff Gas Gas Storage Ground water Figure 2.4 Water Movements in the Landfill Rainfall acts as a medium of transportation for leaching and migration of contaminants from a landfill. Rainfall also provides the required moisture content for methane production and biological activity. Figure 2.5 shows that the leachate production varies to a great extent with the amount of rainfall. It has been experienced that in hot and humid climates, leachate production is much higher and varies more than in hot and arid regions due to intensive microbial activity (Trankler, et al., 2001). During dry season, the leachate production is very low due to the evaporation whereas in raining season, the leachate production is related to amount of rainfall intensity. Therefore, when designing a landfill for disposal of municipal waste, and developing a treatment scheme for leachate treatment, the quality and quantity of leachate may be influenced by climate and microbial activity. On the other side, though high rainfall leads to increased leachate production, it reduces leachate strength due to the dilution. The quality of leachate produced may be regarded as proportional to the volume of water percolating through the landfill waste. Reduction of the quantity of water entering the tip is therefore of great importance in reducing the rate of leachate generation (Tatsi and Zouboulis, 2002). Few researchers have measured the temporal variation in leachate production as 2-45 L/s, depending largely on the precipitation over the landfill (Martin, et al., 1995). The influence of seasonal variation in the landfill leachate quality and quantity varies from place to place which is also influenced by other factors. It is necessary to consider the hydrological and leachate quality data while suggesting a treatment for leachate to avoid environmental deterioration problems caused by direct disposal. 13 Surface runoff Leachate
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: Table 2.3 presents the general leac
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 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
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MW larger than 50 kDa, (2) MW betwe
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Figure 3.7 Flowchart Showing Ammoni
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Chapter 4 Results and Discussion 4.
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COD Removal Effeciency (%) COD Remo
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MLSS (mg/L) 14000 12000 10000 8000
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Specific Growth Rate ( d -1 ) 0.50
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change in the predominant species w
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Table 4.4 Effect of Free Ammonia Co
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Table 4.5 Substrate Utilization by
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4.3.1 Initial Membrane Resistance P
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when compared with the present stud
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COD Removal Efficiency (%) 90 80 70
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(2) TKN Removal Efficiency Prior to
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As there was no significant improve
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The probable reason for frequent fo
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Ammonia Concentration (mg/L) Ammoni
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concentration after treatment. Othe
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After the chemical cleaning of the
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emoval of 38%. A higher removal in
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Influent BOD (mg/L) Influent BOD (m
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(3) TKN Removal Efficiency The TKN
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Figure 4.34 gives the overall TKN r
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fraction and slowly biodegradable C
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BOD (mg/L) BOD (mg/L) 6000 5000 400
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Figure 4.39 Molecular Weight Cut-of
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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
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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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