COMMERCIALIZATION OF ANAEROBIC CONTACT PROCESS FOR ANAEROBIC DIGESTION OF ALGAE by GUNJAN ANDLAY Submitted in partial fulfillment of the requirements for the degree of Master of Science DEPARTMENT OF BIOLOGY CASE WESTERN RESERVE UNIVERSITY May 2010 CASE WESTERN RESERVE UNIVERSITY SCHOOL OF GRADUATE STUDIES We hereby approve the thesis/dissertation of _____________________________________________________Gunjan Andlay Master of Science candidate for the ______________________degree *. Claudia M. Mizutani, Ph.D. (signed)_______________________________________________ (chair of the committee) Christopher A. Cullis, Ph.D. ________________________________________________ Andrew K. Swanson, Ph.D. ________________________________________________ David J. Burke, Ph.D. ________________________________________________ ________________________________________________ ________________________________________________ April 2, 2010 (date) _______________________ *We also certify that written approval has been obtained for any proprietary material contained therein. Dedicated to my parents, and family 2 Table of Contents List of tables ................................................................................................................................... 5 List of figures ................................................................................................................................. 6 ACKNOWLEDGEMENTS ......................................................................................................... 7 List of abbreviations ..................................................................................................................... 8 Abstract ........................................................................................................................................... 9 1. INTRODUCTION .............................................................................................................. 10 2. ANAEROBIC DIGESTION .............................................................................................. 12 2.1 Anaerobic Digestion at commercial level .......................................................... 12 3. ANAEROBIC DIGESTION – THE PROCESS ............................................................. 13 3.1 Stages of Anaerobic Digestion ........................................................................... 13 4. FACTORS AFFECTING PERFORMANCE OF ANAEROBIC DIGESTION ........ 17 4.1 Chemical Oxygen Demand ................................................................................ 18 4.2 C/N Ratio............................................................................................................ 19 4.3 pH and Alkalinity ............................................................................................... 20 4.4 Volatile Solids .................................................................................................... 20 4.5 Total Suspended Solids ...................................................................................... 20 4.6 Fats, Oils and Grease .......................................................................................... 21 4.7 Solids Residence time ........................................................................................ 21 4.8 Hydraulic Retention time ................................................................................... 22 4.9 Agitation ............................................................................................................. 22 4.10 Temperature ....................................................................................................... 22 4.11 COD removal efficiency .................................................................................... 23 4.12 Inoculum growth rate ......................................................................................... 23 4.13 Biogas output...................................................................................................... 24 4.14 Sludge output...................................................................................................... 24 5. INHIBITION OF ANAEROBIC DIGESTION PROCESS .......................................... 26 5.1 Ammonia ............................................................................................................ 26 3 5.2 Sulphide .............................................................................................................. 27 5.3 Light metals (Na, Al, K, Ca, Mg) ....................................................................... 27 5.4 Heavy metals ...................................................................................................... 28 5.5 Organic compounds ............................................................................................ 29 6. ALGAL SPECIES AND ANAEROBIC DIGESTION ................................................. 31 7. ANAEROBIC DIGESTION TECHNOLOGIES ........................................................... 34 7.1 Anaerobic Lagoon .............................................................................................. 35 7.2 Anaerobic contact process .................................................................................. 36 7.3 Upflow Anaerobic Sludge Blanket Reactor ....................................................... 37 7.4 Upflow/Downflow Anaerobic Filtration (Biofilm) process ............................... 38 7.5 Anaerobic Expanded / Fluidized Bed Reactor ................................................... 39 7.6 Anaerobic Membrane Reactor ........................................................................... 40 7.7 Bulk Volume Fermenter ..................................................................................... 41 7.8 Plug Flow Reactor .............................................................................................. 41 7.9 Continuous Stirred Tank Reactor (Complete Mix reactor) ................................ 42 7.10 Anaerobic Sequence Batch Reactor ................................................................... 42 8. ANAEROBIC DIGESTION TECHNOLOGY MATRIX ............................................. 43 8.1 COD loading rate ............................................................................................... 43 8.2 COD removal efficiency .................................................................................... 43 8.3 Influent solids concentration .............................................................................. 44 8.4 Theoretical biogas output ................................................................................... 44 8.5 Comparison of Anaerobic Contact Process with Other Processes ..................... 46 9. COMMERCIAL FEASIBILITY OF ANAEROBIC CONTACT PROCESS ............ 49 10. CONCLUSION ................................................................................................................... 56 11. BIBLIOGRAPHY ............................................................................................................... 57 4 List of tables Table 1: List of factors affecting anaerobic digestion performance ................................. 18 Table 2: Estimated methane outputs of microalgal species .............................................. 32 Table 3: Anaerobic digestion of algal species at laboratory scale .................................... 33 Table 4: List of anaerobic digestion technologies with advantages and disadvantages ... 34 Table 5: Anaerobic Digestion Technology matrix ............................................................ 45 Table 6: Cost comparison of Anaerobic Contact process with other processes ............... 48 Table 7: CapEx and OpEx calculations for Anaerobic contact process ........................... 53 5 List of figures Figure 1: Anaerobic Lagoon ............................................................................................. 35 Figure 2: Anaerobic contact process ................................................................................. 36 Figure 3: Upflow Anaerobic Sludge Blanket Reactor ...................................................... 37 Figure 4: Upflow Anaerobic Filtration process ................................................................ 38 Figure 5: Anaerobic Expanded/Fluidized Bed Reactor .................................................... 39 Figure 6: Anaerobic Membrane Reactor ........................................................................... 40 6 ACKNOWLEDGEMENTS I am extremely grateful to Dr. Christopher A. Cullis, Chair, Department of Biology and Director, MS Entrepreneurial Biotechnology, Case Western Reserve University for constantly guiding and supporting me at each and every step and continuously interacting with me to help in my gradual improvement as a biologist and an entrepreneur. I extend my sincere gratitude to Dr. Andrew K. Swanson, Vice President, R&D, Phycal LLC for guiding me throughout the internship at Phycal by being an excellent supervisor and my thesis advisor. I am indebted to Mr. Martin L. Johnson, P.E. and Mr. Aaron B. Brister (Phycal) and Dr. Mark W. Tenney, P.E. (Independent Consultant) for their extraordinary guidance and assistance on this project. I am extremely thankful to the professors at Department of Biology, Case Western Reserve University, Dr. David J. Burke, for serving on the thesis committee and Dr. Claudia M. Mizutani, for being the Chair of the thesis committee. I am very much contented after fruitfully completing this project