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

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obtain high treatment efficiencies of 76% TKN, 60% COD, 84% phosprorus removal at HRT of 7 hours and with a F/M ratio of 1.73 g COD/g MLSS.d. The maximum specific growth rate of C. utilis was found to be 0.19 h -1 Hu (1989) used ten different yeast strains in cultures to treat vermicelli wastewater which contained BOD ranging from 24,000 to 44,000 mg/L and high concentration of starch, lactic acid and protein. Based on the ability of starch degradation, protein hydrolysis and lactic acid tolerance, these yeast strains were screened from 391 colonies isolated from soil samples. Most of them could grow well with pH range of 3.0-5.0, 4.0 being the optimum. The results shows that the two strains could reduce soluble COD by 92% at HRT of 7 days, F/M ratio of 0.48 g COD/g MLSS.d and VLR of 1.03 kg COD/m 3 .d. Due to the poor settling ability of yeasts, they could not be flocculated or settled as in a conventional activated sludge process and were easily washed out with the effluent. Therefore, the HRT in this process have to keep long and same as the SRT. The author postulated that the fungi contamination prevented the formation of yeast flocs. Chigusa, et al. (1996) used nine different strains of yeasts capable of decomposing the oil to treat wastewater from oil manufacturing plants. A pilot scale yeast treatment system had been run for one year. According to the results, 10,000 mg/L of hexane extracts in the raw wastewater were reduced by the yeast mixture to about 100 mg/L. Elmaleh et al.(1996) investigated the yeast treatment of highly concentrated acidic wastewater from the food processing industry. The strain Candida utilis was cultured in continuously completed mixed reactors. This system did not have a separate settling tank; the SRT and HRT of the system were identical. A mixture of acetic acid, propionic and butyric acid was the carbon source of feed wastewater. The pH was maintained at 3.5 to prevent any bacterial contamination. The TOC removal obtained was 97% at high loading rates (30 kg TOC/m 3 .d). The growth yield and maximum specific growth rate of yeasts were similar to those for conventional activated sludge (µmax = 0.5 h - ; Y = 0.85-1.05 kg SS/kg TOC for acetic acid). Olive mill wastewater normally contains high concentration of fats, sugars, phenols, volatile fatty acids which contribute to a very high COD concentration (100,000-200,000 mg/L). Scioli and Vollaro (1997) reported that Yarrowia lipolytica cultured in aerated fermenter was capable of reducing the COD level of olive oil processing wastewater by 80% in 24 h. Fats and sugars were completely assimilated while methanol and ethanol were present. The effluent had a pleasant smell due to the presence of these compounds. The authors asserted that a possible approach for pollution reduction in olive-oil-producing countries is to use membrane to filter effluent before discharging into the sewage system. Useful biomass (40% protein) and valuable lipase enzyme could also be obtained in this process. Arnold, et al. (2000) investigated the ability of selected yeast strains (C. utilis and Galactomyces geotrichum) to purify silage wastewater containing high COD concentration of 30,000 to 80,000 mg/L by using the shaker-flask. High removal efficiencies of COD (74-95%), VFA (85-99%) and phosphate (82-99%) were obtained after 24 hrs and some ammonia was also removed. During treatment, pH rose from initial values of 3.7-5.8 to 8.5-9.0. This was presumably due to removal of lactic acid and VFAs. An efficient removal of P from the system could lead to the shortage of phosphorus. 50
Nishihara ESRC Ltd. (2001) studied the effect of the Yeast Cycle System on dried food and marine products processing wastewater. In this system, the yeast treatment/pretreatment could be conducted with high organic and nutrient loadings. The organic removal obtained was more than 90%. Moreover, this system is relatively unaffected by load variation and the structure of yeast flocs facilitated oxygen diffusion. Table 2.20 gives a comparison with conventional complete mixing activated sludge in terms of the operating conditions. Dried food products processing wastewater has BOD5 concentrations ranging from 2,920-15,800 mg/L and SS concentration 1,360 mg/L. Marine products processing wastewater has BOD5 and SS concentrations ranging from 3,550- 8,850 mg/L and 680-940 mg/L respectively. Some yeast strains, Candida edax, Candida valdivana and Candida emobii, were predominantly grown during enrichment with this raw wastewater. The predominance of yeast strains with the enrichment culture technique is based on free competition among different organisms in real wastewater. It was found that the yeast treatment process can obtain high efficiency at a higher volumetric loading (5–6 times), F/M ratio (2–3 times) when compared with the AS process. The efficiency of this system is presented in Table 2.21. Table 2.20 Operating Conditions of Yeast System Compared with Activated Sludge Process (Nishihara ESRC Ltd., 2001) Parameter Unit Dried Food Marine Activated Products Products Sludge* Influent BOD5 BOD5 volumetric loading mg/L kg/m 5,200 5,450 110-400 3 .day 9.12 8.48 0.8 – 1.9 Yeast concentration mg/L 8,000-13,500 8,000- 10,000 2,500 – 4,000 BOD5 sludge loading kgBOD5 0.9 0.9 0.2 – 0.6 (F/M) /kgVSS.day Water temperature °C 27 26 23 – 30 pH 6.5 4.8 6.5 – 8.5 DO mg/L 0.8 0.7 ≥ 2 SVI ml/g 53 66 100 – 120 Remark * Complete mixed activated sludge (Tchobanoglous and Burton, 1991) Table 2.21 Performance of Yeast Based Treatment System in Dried Food Products and Marine Product Industry (Nishihara ESRC Ltd., 2001) Parameter (mg/L) Dried Food Products Marine Products BOD5 SS T-N T-P Cl - BOD5 SS T-N T-P Cl - Influent After pretreatment 5,450 798 153 33 5,160 5,218 1,360 198 38 1,080 by yeast 150 113 72 18 5,080 118 95 109 22 1,068 Efficiency (%) After activated 97 86 53 46 2 98 93 45 42 1 sludge 4 15 10 15 5,080 12 18 16 7 1,068 Efficiency (%) 97 87 86 17 - 90 81 85 68 - 51
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
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4.4 Effect of Free Ammonia Concentr
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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 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: 2.12 Yeasts 2.12.1 Introduction The
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
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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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