Thạc Sĩ Airlift assisted wastewater treatment

ACKNOWLEDGEMENTS
As with many learning experiences, graduate school has taught me things that extend far beyond the classroom. One of the greatest lessons learned relates to the fact that perseverance has allowed me to accomplish much more than I would have originally felt possible. I would first like to acknowledge Cedric Brown with TESI, Inc., for providing to me first hand interaction with domestic wastewater treatment. I would also like to thank the previous graduate students and friends Steven, Pavani, Cynthia, and Chris for their unselfish help throughout the process. In addition, I would like to thank Mr. Dale for helping me clarify my data sets. I would be remiss if I did not mention Mrs. Sandy and her constant support with the entire process.
Thank you to my Committee members Dr. Frank Tsai and Dr. Chandra Theegala. Their guidance has allowed me to understand the subtle details associated with hydraulics and technical writing. For this endeavor towards graduate school but more importantly the capacity to confidently tackle the extreme unknown I give thanks to Dr. Ron Malone. I have learned that one of the greatest assets that every individual possesses is his or her time. My life has been forever changed because I was able to capture a great deal of this intangible asset from Dr. Malone. He consistently maintains the bar as an educator.
This opportunity would not have been possible without the support of my family. I would like to thank my in-laws Mr. David, Mrs. Judy, Mr. Mark and Mrs. Angela for their vigilant help with the day to day struggles that were compounded with this lengthy effort. To my parents, Sidney and Mary Jane, you have always been my biggest fans and without your guidance and persistent “Push” I would not have made it. Your love is truly selfless and I hope to manifest that with my children. Rachel, Laura, and Amy thank you for your support with each of my steps along the way, I did it. Finally, I would like to thank my wife Shelley and two
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children Bruen and Matilda. Your position demanded unending fortitude and extraordinary character for the deep valleys and the short peaks and it was always there. You were always the beginning and the end all along the way. I am because of you, Thank You for that.
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TABLE OF CONTENTS
ACKNOWLEDGEMENTS ii
LIST OF TABLES .vi
LIST OF FIGURES vii
ABSTRACT .ix
CHAPTER 1. INTRODUCTION 1
Biological Treatment of Wastewater .3
CHAPTER 2. LITERATURE REVIEW .5
Static Low Density Media Filtration 5
Airlift Pump History 9
Airlift Pump Operation 9
Submergence Depth to Lift Height Ratio, S:L .10
Gas to Liquid Ratio, Qg:Q 12 w
Riser Pipe Diameter and Air Injection Method .13
Airlift Pump Flow Regimes .14
CHAPTER 3. METHODS AND MATERIALS .16
Experimental Apparatus .16
Experimental Protocol .23
Water Flow Discharge .23
Aeration Capacity 27
CHAPTER 4. RESULTS AND DISCUSSION .29
Airlift Pump Discharge 29
Airlift Discharge Potential with Increasing Air Input and S:L Ratio 30
Airlift Discharge Potential with Increasing Air Input and Lift Height 31
Airlift Discharge Potential Using Multiple Draft Tubes 32
Airlift Discharge Potential Qg:Q 33 w
Conclusion of Optimal Flow Discharge Configuration .34
Airlift Pump Oxygen Transfer .36
Airlift Oxygen Transfer for Differing Initial Concentrations 37
Conclusion of Oxygen Transfer .38
CHAPTER 5. CONCLUSION .40
REFERENCES 43
APPENDIX A: SUPPLEMENTAL GRAPHS 47
APPENDIX B: SUPPLEMENTAL VIEWS OF EXPERIMENTAL APPARATUS .50
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APPENDIX C: PITOT TUBE DESIGN RECOMMENDATIONS 51
APPENDIX D: DATA GENERATED FOR GENERALIZED RELATIONSHIP BETWEEN LIFT AND SUBMERGENCE .53
APPENDIX E: RAW AND COMPUTED DATA FOR THE FIRST SET OF DISCHARGE EXPERIMENTS 54
APPENDIX F: RAW AND COMPUTED DATA FROM THE SECOND SET OF OXYGEN TRANSFER EXPERIMENTS .69
VITA 173
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LIST OF TABLES
Table 3-1 Description of various components used in experimental apparatus 20
Table 5-1 Design rules prescribed for 6″ airlift pump use when combined with 25 ft3 PolyGeyser® filters in domestic wastewater treatment applications .42
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LIST OF FIGURES
Figure 1-1 The consolidation of multiple unit operations into one bioclarifier simplifies the treatment strategy .2
Figure 2-1 SLDM filters normally operate with a packed bed. The bed expands when a backwash occurs allowing excess biofloc to settle as sludge. (Bellelo et. al., 2006) 7
Figure 2-2 Sketch of common airlift pump showing the difference between static lift, dynamic lift, and submergence (Gudipati, 2005) 11
Figure 2-3 Two-Phase flow regimes in airlift pumps as air input increases (Reinemann and Timmons, 1988) .15
3Figure 3-1 Flow chart for air and water travel throughout the 25 ft SLDM filter and 6″ airlift pump combination 17
3Figure 3-2 The experimental apparatus used for testing consisted of the 25 ft filter, the double draft airlifts, the external reservoir, the catch basin, the blower, and various pitot tubes 18
Figure 3-3 10″ x 6″ diverter channel receiving flow from the discharge section of the airlift pump and spilling into the catch basin (L) .21
Figure 3-4 Pitot tube locations used on the experimental filter and 6” airlift pump .21
Figure 3-5 Venturi flow measurement apparatus used for testing .22
Figure 3-6 External overflow circulation system used in the experimental tests 24
Figure 3-7 Venturi curve calibrated for applicable flow range tested .26
Figure 4-1 Both S:L and Q will positively enhance Qgw in a 6 inch airlift pump for lift heights ranging from 9 to 15 inches 30
Figure 4-2 Qw increases logarithmically with Q and S:L .31g
Figure 4-3. When L is confined to 15″ or less, S may be as important as Q for enhancing Q.32gw
Figure 4-4 The double draft tube in the current configuration could not yield the multiplicative Qw expected because of frictional velocity constraints 32
Figure 4-5 The optimum Q:Qgw appears to increase with S:L .34
Figure 4-6 Qw increases linearly with S:L .35
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Figure 4-7 Optimal Qw for a 12″ L and 4:1 S:L configuration using a 6″ draft tube was observed within a water velocity of 1 to 2 ft/sec of which corresponds to a maximum Qg of 22 cfm .36
Figure 4-8 Oxygen transfer in a 6” airlift pump increases at a proportional rate to air input and Cdeficit .37
Figure 4-9 The rate at which oxygen is transferred into the water appears to max out at Qg equal to 25 cfm .38
Figure 4-10 Oxygen transfer in 6″ airlift pumps can be correlated to air input and C .39deficit
Figure 5-1 The 6″ airlift pump can supply adequate aeration to sustain both carbon oxidation and nitrification in the bead bed at the lowest suggested Q 40