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A pilot scale study of combining struvite precipitation with UniBAR-anammox process as a sustainable… Kalam, Sifat 2015

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A PILOT SCALE STUDY OF COMBINING STRUVITE PRECIPITATION WITH UNIBAR-ANAMMOX PROCESS AS A SUSTAINABLE UNIFIED SOLUTION FOR MANAGING NUTRIENTS IN CENTRATE by Sifat Kalam B.Sc. (Civil Engg.), Bangladesh University of Engineering and Technology Dhaka, Bangladesh, 2011 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIRMENTS FOR THE DEGREE OF  MASTER OF APPLIED SCIENCE in The Faculty of Graduate and Postdoctoral Studies (Civil Engineering) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) May 2015 © Sifat Kalam, 2015   ii  Abstract Nitrogen (N) and phosphorus (P) from wastewater discharges are the primary causes of eutrophication in receiving water bodies. Removal and recovery of nutrients from wastewater is important, due to their high demand as fertilizer.  Two well established technologies, struvite precipitation for P-removal and anammox process for N-removal, are combined in this study to manage both nutrients concurrently. A pilot-scale study was conducted at the Annacis Wastewater Treatment Plant Research Center in Delta, BC, combining Struvite precipitation using the UBC Crystallizer with the UniBAR-anammox process, in two possible combination sequences. In combination 1 (Pre-Anammox-Struvite process), an average combined removal efficiency of 90.8±1.8% P and 79.2 ± 1.9% N was achieved. The anammox process was not affected by the chemical load (caustic and magnesium) from the struvite process. The UniBAR-anammox process showed similar behaviour pattern for both centrate and struvite effluent feed, achieving over 70% N-removal. Batch test results at different temperatures indicated that the anammox process performed better at higher temperature, for both feeds. N-removal efficiency decreased from around 70% to 57%, as the   mp                    om 34    o 25    In  om in  ion 2  Po  -Anammox-Struvite process), the average combined N and P removal efficiencies were 71.0±5.2% and 90.8±1.8 %, respectively. With the change in struvite influent after combination (from centrate to anammox effluent feed), while using the same pH set point of 7.67, P-removal decreased, due to a lower N: P molar ratio. A higher pH set point of 8.30, to maintain desired supersaturation ratio, resulted in 90% removal. However, higher caustic consumption was introduced in  iii  combination 2, compared to the negligible amount in combination 1. Pure struvite pellets were recovered from both combinations.  iv  Preface This dissertation is original, unpublished, independent work by the author, Sifat Kalam   v  Table of Contents  Abstract ........................................................................................................................ ii Preface ......................................................................................................................... iv Table of Contents ..........................................................................................................v List of Tables ............................................................................................................... ix List of Figures................................................................................................................x Nomenclature .............................................................................................................. xv Acknowledgements .....................................................................................................xix Dedication ...................................................................................................................xxi 1 Introduction ...........................................................................................................1 1.1 Background .....................................................................................................1 1.2 Research Objectives .........................................................................................2 1.3 Research Questions ..........................................................................................3 2 Literature Review ..................................................................................................5 2.1 Importance of Wastewater Nutrient Management ............................................5 2.1.1 Environmental Concern ...............................................................................5 2.1.2 Stringent Regulations ...................................................................................5 2.1.3 Problems in Wastewater Treatment Plants....................................................7 2.1.3.1 Additional Nutrient Load From Dewatered Sludge Liquor or Centrate .7 2.1.3.2 Unintentional Struvite Formation .........................................................8 2.1.4 Global Phosphorus and Nitrogen Cycle ........................................................9 2.1.5 Supply and Demand of Phosphorus and Nitrogen ....................................... 10 2.1.6 Economic Considerations ........................................................................... 12 2.2 Wastewater Nutrients Management Techniques ............................................. 13 2.3 Phosphorus Management ............................................................................... 13 2.3.1 Physical Treatment .................................................................................... 13 2.3.2 Chemical Treatment ................................................................................... 14 2.3.2.1 Calcium Phosphate Precipitation ........................................................ 14 2.3.2.2 Chemical Precipitation by Iron or Aluminum ..................................... 15 2.3.2.3 Struvite Precipitation Process ............................................................. 15 2.3.2.4 P-Removal by Ion Exchange .............................................................. 16 2.3.3 Biological Treatment ................................................................................. 16 2.4 Nitrogen Management ................................................................................... 17 2.4.1 Physical Treatment .................................................................................... 17 2.4.1.1 Gas Stripping ..................................................................................... 17 2.4.1.2 Microwave Technique ........................................................................ 18  vi  2.4.2 Chemical Treatment ................................................................................... 18 2.4.2.1 Breakpoint Chlorination ..................................................................... 18 2.4.2.2 Struvite (MAP) Precipitation .............................................................. 19 2.4.2.3 Selective Ion Exchange ...................................................................... 19 2.4.3 Biological Treatment ................................................................................. 20 2.4.3.1 Conventional Nitrification and Denitrification .................................... 20 2.4.3.2 Nitrification........................................................................................ 20 2.4.3.3 Denitrification .................................................................................... 21 2.4.3.4 Anaerobic Ammonium Oxidation (ANAMMOX) .............................. 22 2.5 Anammox Process for N-removal .................................................................. 23 2.5.1 Mechanism of Anammox Process .............................................................. 23 2.5.2 UniBAR-Anammox Reactor ...................................................................... 25 2.5.3 Key Factors for Controlling UniBAR-Anammox Process........................... 27 2.5.3.1 Dissolved Oxygen .............................................................................. 27 2.5.3.2 pH ...................................................................................................... 27 2.5.3.3 Temperature ....................................................................................... 28 2.5.3.4 Nitrite Accumulation .......................................................................... 28 2.5.3.5 Ammonium Concentration ................................................................. 29 2.5.4 Application of Anammox Technology in WWTPs ..................................... 30 2.6 Struvite Process for P-removal ....................................................................... 31 2.6.1 Struvite Chemistry ..................................................................................... 31 2.6.2 Fluidized Bed UBC-Crystallizer for Struvite Precipitation Process............. 31 2.6.3 Key Factors for Controlling Struvite Precipitation Process ......................... 32 2.6.3.1 Solubility Product and Supersaturation Ratio...................................... 32 2.6.3.2 pH ...................................................................................................... 33 2.6.3.3 Temperature ....................................................................................... 33 2.6.3.4 Turbulence ......................................................................................... 34 2.6.3.5 Molar Ratios ...................................................................................... 34 2.6.3.6 Presence of Impurities ........................................................................ 35 2.6.4 Application of Struvite Technology in WWTPs ......................................... 35 3 Materials and Methods........................................................................................ 36 3.1 Project Outline ............................................................................................... 36 3.2 Influent (Centrate) Characteristics.................................................................. 37 3.3 Process Combinations .................................................................................... 39 3.3.1 Combination 1: Pre-Anammox-Struvite Process ........................................ 39 3.3.2 Combination 2: Post-Anammox-Struvite Process ....................................... 40 3.4 Experimental Set up ....................................................................................... 41 3.4.1 Struvite Reactor Setup ............................................................................... 41 3.4.1.1 Struvite Reactor Design ...................................................................... 41 3.4.1.2 External Clarifier for Struvite Column ................................................ 44 3.4.1.3 Process Feed, Storage tanks and Pumps .............................................. 45 3.4.1.4 Process Operations ............................................................................. 46 3.4.2 Anammox Reactor Setup for Combination 1 .............................................. 46 3.4.2.1 Anammox Reactor Design.................................................................. 46 3.4.2.2 External Clarifier for Anammox Process ............................................ 47 3.4.2.3 Process Feed, Storage Tanks and Pumps ............................................ 47  vii  3.4.2.4 Process Operations ............................................................................. 48 3.4.3 Anammox Reactor Setup for Combination 2 .............................................. 53 3.4.3.1 Anammox Reactor Design.................................................................. 53 3.4.3.2 External Clarifier for Anammox Process ............................................ 54 3.4.3.3 Process Feed, Storage Tanks and Pumps ............................................ 54 3.4.3.4 Process Operation .............................................................................. 55 3.5 Reactor Operating Conditions ........................................................................ 60 3.6 Monitoring and Maintenance ......................................................................... 61 3.7 Sample Collection and Preservation ............................................................... 62 3.8 Sample Analysis ............................................................................................ 62 3.9 Analytical Methods ........................................................................................ 63 3.9.1 pH.............................................................................................................. 63 3.9.2 Alkalinity ................................................................................................... 63 3.9.3 Ammonia-Nitrogen (NH3-N) ..................................................................... 63 3.9.4 Nitrite-Nitrogen (NO2-N) ........................................................................... 64 3.9.5 Nitrate-Nitrogen (NO3-N) .......................................................................... 64 3.9.6 Ortho-Phosphate (PO4-P) ........................................................................... 64 3.9.7 Magnesium (Mg) ....................................................................................... 64 3.9.8 Caustic (NaOH) ......................................................................................... 65 3.9.9 Total Suspended Solids and Total Dissolved Solids (TSS and VSS) ........... 65 3.9.10 Particle Size Distribution........................................................................ 66 3.9.11 Sieve Analysis of Struvite Pellets ........................................................... 66 3.9.12 Chemical Analysis of Struvite Pellets ..................................................... 66 3.9.13 XRD Analysis of Struvite Pellets ........................................................... 67 3.10 Terminology .................................................................................................. 67 3.10.1 Removal Efficiency................................................................................ 67 3.10.2 Hydraulic Retention Time (HRT) ........................................................... 67 3.10.3 Recycle Ratio ......................................................................................... 68 3.11 Statistical Analysis ........................................................................................ 68 4 Results and Discussion ........................................................................................ 69 4.1 Influent Characteristics (Centrate).................................................................. 69 4.2 Combination 1 (Pre-Anammox-Struvite Process) Results............................... 71 4.2.1 Phosphorus and Nitrogen Removal in Combination 1 ................................ 71 4.2.1.1 P-Removal in Combination 1 ............................................................. 71 4.2.1.2 N-Removal in Combination 1 ............................................................. 73 4.2.2 Variation in Wastewater Characteristics Before and After Combination 1 .. 76 4.2.3 Effect of Struvite Effluent Feed on UniBAR-Anammox Process ................ 85 4.2.4 Effect of Struvite Effluent Feed and Temperature on UniBAR-Anammox Process Behavior (Batch Test Results) ................................................................... 88 4.3 Combination 2 (Post-Anammox-Struvite Process) Results ............................. 93 4.3.1 Phosphorus and Nitrogen Removal in Combination 2 ................................ 94 4.3.1.1 P-Removal in Combination 2 ............................................................. 94 4.3.1.2 N-Removal in Combination 2 ............................................................. 96 4.3.2 UniBAR-Anammox Process Results .......................................................... 98 4.3.3 Variation in Wastewater Characteristics Before and After Combination 2 103  viii  4.3.4 Effect of Anammox Effluent Feed on Struvite Precipitation Process and Caustic Consumption........................................................................................... 111 4.4 Struvite Pellets Analysis in Combination 1 and 2 ......................................... 113 5 Conclusions and Recommendations ................................................................. 120 5.1 Conclusions ................................................................................................. 120 5.2 Recommendations for Future Work ............................................................. 122 References.................................................................................................................. 124 Appendices ................................................................................................................ 133 Appendix A: Calculations for Upflow Velocity and Reynolds Number .................. 134 Appendix B: XRD Analysis Results of Struvite Pellets............................................ 136 Appendix C: Data Sheet ............................................................................................ 142    ix  List of Tables  Table 2.1: Water quality guidelines for total ammonia for the protection of aquatic life (mg/L NH3)(CCME, 2010) ..............................................................................................6 Table 2.2: World supply, demand and potential balance of Nitrogen and Phosphorus .... 12 Table 3.1: Struvite column design values ...................................................................... 43 Table 3.2: Reactor operating conditions for process combinations ................................. 60 Table 4.1: Annacis centrate characteristics (February to December 2014) ..................... 69 Table 4.2: Average particle size in combination 1 ......................................................... 84 Table 4.3: Effect of struvite effluent feed and temperature on anammox process cycle time in batch test ........................................................................................................... 89 Table 4.4: Effect of struvite effluent feed and temperature on anammox process N-removal in batch test ..................................................................................................... 91 Table 4.5: Average particle size in combination 2 ....................................................... 110 Table 4.6: Sieve analysis results of struvite pellets ...................................................... 113 Table 4.7: Chemical analysis results of struvite pellets ................................................ 118     x  List of Figures  Figure 1.1: Pilot Scale study of combining Struvite precipitation and UniBAR-anammox process ............................................................................................................................3 Figure 2.1 Dewatered sludge liquor or Centrate recycled to WWTP headworks adopted from (Munch and Barr, 2001) ..........................................................................................8 Figure 2.2: Nitrogen cycle (Environment Canada, 2001) .................................................9 Figure 2.3 :Anammox bacteria in the global Nitrogen cycle adopted from  (Trimmer et al., 2003) ....................................................................................................................... 24 Figure 2.4: Mechanism of Anammox process adopted from (Jetten et al., 2001) ............ 25 Figure 3.1:  Process flow diagram of AWWTP .............................................................. 36 Figure 3.2: Ammonia-Nitrogen variation in centrate ...................................................... 38 Figure 3.3: Ortho-Phosphate variation in centrate .......................................................... 38 Figure 3.4: Combination 1 (Pre-Anammox-Struvite Process) ........................................ 39 Figure 3.5: Combination 2 (Post-Anammox-Struvite Process) ....................................... 40 Figure 3.6: Injection port of pilot scale UBC crystallizer ............................................... 42 Figure 3.7: External clarifier of struvite column ............................................................ 44 Figure 3.8: Process flow diagram of Pre-Anammox-Struvite process (combination 1) ... 51 Figure 3.9: Pilot scale experimental setup for Pre-Anammox-Struvite process (combination 1) ............................................................................................................. 52 Figure 3.10: Heating system installed for pilot scale anammox reactor .......................... 53 Figure 3.11: Anammox bacteria under microscope; left image at start up and right image after sludge enrichment ................................................................................................. 56  xi  Figure 3.12: Mature anammox granule .......................................................................... 57 Figure 3.13: Process flow diagram of Post-Anammox-Struvite process (combination 2)58 Figure 3.14: Pilot scale experimental setup for Post-Anammox-Struvite process (combination 2) ............................................................................................................. 59 Figure 3.15: Nitrite test by colorimetric method ............................................................ 61 Figure 4.1: Sampling locations and notations for Combination 1 ................................... 71 Figure 4.2: Phosphorus removal in Struvite process (Combination 1) ............................ 72 Figure 4.3: Percentage removal of P and N in Struvite process (Combination 1) ............ 72 Figure 4.4: Ammonia removal in Struvite process (Combination 1) ............................... 73 Figure 4.5: Ammonia-Nitrogen concentration in Combination 1.................................... 74 Figure 4.6: N-removal efficiency in Combination 1 ....................................................... 75 Figure 4.7: Average N-removal in Combination 1 ......................................................... 76 Figure 4.8: TSS variation in Combination 1 .................................................................. 77 Figure 4.9: VSS variation in Combination 1 .................................................................. 77 Figure 4.10: Nitrate-Nitrogen variation in Combination 1 .............................................. 78 Figure 4.11: Nitrite-Nitrogen variation in Combination 1 .............................................. 79 Figure 4.12: Nitrite-Nitrogen variation in Combination 1 removing reactor failure data points ............................................................................................................................ 80 Figure 4.13: Alkalinity variation in Combination 1 ........................................................ 81 Figure 4.14: pH variation in Combination 1 .................................................................. 82 Figure 4.15: Conductivity measurements in Combination 1 ........................................... 82 Figure 4.16: Average Conductivity values in Combination 1 ......................................... 83 Figure 4.17: Particle size distribution Combination 1 .................................................... 84  xii  Figure 4.18: Comparison of average pH and NO2-N values before and after Combination1 ............................................................................................................... 85 Figure 4.19: Comparison of average NO3-N, Alkalinity, TSS and VSS values before and after Combination 1 ...................................................................................................... 86 Figure 4.20: Anammox reactor behaviour (HRT, pH, NO2-N) before and after Combination 1 (Error bar showing 95%CI) ................................................................... 86 Figure 4.21: Anammox reactor behaviour (Alkalinity and NO3-N) before and after Combination 1 (Error bar showing 95%CI) ................................................................... 87 Figure 4.22: Anammox reactor behaviour (TSS and VSS) before and after Combination 1 (Error bar showing 95%CI) ........................................................................................... 87 Figure 4.23: Effect of Struvite effluent feed and temperature on Anammox reactor pH . 88 Figure 4.24: Effect of Struvite effluent feed and temperature on Anammox reactor alkalinity ....................................................................................................................... 90 Figure 4.25: Effect of Struvite effluent feed and temperature on Anammox reactor dissolved oxygen level .................................................................................................. 90 Figure 4.26: Effect of Struvite effluent feed and temperature on Anammox reactor ammonia-nitrogen concentration ................................................................................... 91 Figure 4.27: Effect of Struvite effluent feed and temperature on Anammox reactor nitrite-nitrogen Level ............................................................................................................... 92 Figure 4.28: Effect of Struvite effluent feed and temperature on Anammox reactor nitrate-nitrogen level ..................................................................................................... 92 Figure 4.29: Sampling locations and notations for Combination 2 ................................. 94 Figure 4.30: Phosphorus removal in Struvite Process (Combination 2) .......................... 95  xiii  Figure 4.31: Average percentage P-removal in Struvite process (Combination 2) .......... 95 Figure 4.32: Ammonia-Nitrogen concentration in Combination 2.................................. 96 Figure 4.33: Average N-removal efficiency in Combination 2 ....................................... 97 Figure 4.34: TSS variation within pilot scale Anammox reactor (Combination 2) .......... 98 Figure 4.35: VSS variation within pilot scale Anammox reactor (Combination 2) ......... 98 Figure 4.36: VSS/TSS ratio within pilot scale Anammox reactor (Combination 2) ........ 99 Figure 4.37: N-removal efficiency and HRT in pilot scale Anammox reactor .............. 100 Figure 4.38: Ammonia-Nitrogen concentration in pilot scale Anammox reactor (Combination 2) .......................................................................................................... 101 Figure 4.39: Nitrite-Nitrogen concentration within pilot scale Anammox reactor (Combination 2) .......................................................................................................... 102 Figure 4.40: Nitrate-Nitrogen concentration within pilot scale Anammox reactor (Combination 2) .......................................................................................................... 102 Figure 4.41: TSS variation in Combination 2............................................................... 103 Figure 4.42: VSS variation in Combination 2 .............................................................. 104 Figure 4.43: Nitrite-Nitrogen concentration in Combination 2 ..................................... 105 Figure 4.44: Nitrate-Nitrogen concentration in Combination 2 .................................... 106 Figure 4.45: pH variation in Combination 2 ................................................................ 106 Figure 4.46: Alkalinity variation in Combination 2 ...................................................... 107 Figure 4.47: Conductivity variation in Combination 2 ................................................. 108 Figure 4.48: Average Conductivity in Combination 2 .................................................. 108 Figure 4.49:  Particle size distribution in Combination 2.............................................. 109  xiv  Figure 4.50: Caustic consumption in Struvite precipitation process (Combination 1 and Combination 2) ........................................................................................................... 111 Figure 4.51: Average caustic consumption in Struvite precipitation process in Combination 1 and 2) .................................................................................................. 112 Figure 4.52: Harvested Struvite pellets ........................................................................ 113 Figure 4.53: Struvite pellets size distribution graph ..................................................... 114 Figure 4.54: Pre-Anammox-Struvite pellets under microscope (10X) .......................... 115 Figure 4.55: Post-Anammox- Struvite pellets under microscope (10X) ........................ 115 Figure 4.56: Pre-Anammox-Struvite crystal under microscope, 300X magnification (Centrate Feed) ........................................................................................................... 116 Figure 4.57: Post-Anammox Struvite crystal under microscope, 300X magnification (Anammox Effluent Feed) ........................................................................................... 116 Figure 4.58: XRD analysis of Pre-Anammox-Struvite pellets (2mm size) .................... 117 Figure 4.59: XRD analysis of Post-Anammox-Struvite pellets (2mm size) .................. 117 Figure 4.60: Physical properties of Pre-Anammox-Struvite pellets (2mm size) ............ 119 Figure 4.61: Physical properties of Post-Anammox-Struvite pellets (2mm size) .......... 119  xv  Nomenclature °C Degrees Celsius AAS Atomic Absorption Spectrophotometer ANAMMOX Anaerobic Ammonium Oxidation AOB Ammonia Oxidizing Bacteria ARR Ammonia Removal rate AWC Annacis Wastewater Centre AWWTP Annacis Wastewater Treatment Plant BC British Columbia BNR Biological Nutrient Removal BPR Biological Phosphorus Removal BOD5 Biochemical Oxygen Demand over 5 day (mg/L) CANON Completely Autotrophic Nitrogen Removal CI Confidence Interval CRT Crystal Retention Time CSTR Continuously Stirred Tank Reactor cm Centimetre d Day D10 10th P    n il  o  P   i l  Siz  Di   i   ion  μm) D50 50th P    n il  o  P   i l  Siz  Di   i   ion  μm) D90 90th P    n il  o  P   i l  Siz  Di   i   ion  μm) DO Dissolved Oxygen (mg/L)  xvi  EBPR Enhanced Biological Phosphorus Removal EC Electric Conductivity (mS/cm) FNPT Female-National Pipe Thread gm Grams h Hour H2SO4 Sulfuric Acid HRT Hydraulic Residence Time (h) kg Kilogram kPa Kilopascal Ksp Solubility Product L Litre m Metre MAP Magnesium Ammonium Phosphate Mg Magnesium mg Milligram mL Millilitre mm Millimetre min Minute mS/cm Millisiemens per centimetre MW Microwave N Nitrogen N2 Nitrogen Gas NH3 Ammonia  xvii  NH4+ Ammonium NH4-N Ammonium Nitrogen NO2- Nitrite NO2-N Nitrite Nitrogen NO3- Nitrate NO3-N Nitrate Nitrogen NOB Nitrite Oxidizing Bacteria O2 Oxygen Gas P Phosphorus PAO Polyphosphate Accumulating Organism pH Power of Hydrogen PO4-P Phosphate Phosphorus PS Conditional Solubility Product PSD Particle Size Distribution Q Flow rate (L/day) Re Reynolds Number RR Recycle Ratio RPM Revolutions per Minute s Second SRT Sludge Retention Time (days) SSR Super Saturation Ratio TSS Total Suspended Solids (mg/L) TKN Total Kjeldahl Nitrogen (mg/L)  xviii  TP Total Phosphorus (mg/L) UBC University of British Columbia VFD Variable Frequency Drive VSS Volatile Suspended Solids (mg/L) WWTP Waste Water Treatment Plant XRD X-ray Diffraction μm Micrometre    xix  Acknowledgements   First of all I would like to thank and convey my deepest gratitude to my research supervisor Dr. Donald S. Mavinic, Department of Civil Engineering for his continuous support, supervision and encouragement throughout my years at UBC. I want to thank Dr. Babak Rezania, for giving valuable suggestions related the research, sharing his expertise of Anammox Process and providing mature Anammox bacteria for faster reactor enrichment.  I would like to thank Dr. Sergey Lobanov, for all the XRD analysis he has done for me and also for sharing his expertise in Struvite precipitation process and teaching me PhreeqC modelling. My special thanks to Fred Koch for his suggestions and assistance with struvite reactor assembly and initial set up, Timothy Ma for all the sample analysis work, Scott Jackson and Bill Leung for the technical support. I want to thank Paula Parkinson for helping me with analytical works, placing equipment orders and for always attending me with a smile even at her busiest time.  More importantly, I want to thank my dear friend Jason for his constant support and encouragement. I was lucky to have him by my side at the Annacis Wastewater Center. My heartiest thanks to Patrick Tsao for his help throughout the project at Annacis Wastewater Center. Also I want to thank Sharmeen Farhana, Marcia Fromberg, Afrina Zerin Disha and Greg Archer for helping me with reactor wrap up at the end.  xx  Special thanks to Parssa Hassan for being my mentor and for sharing her experiences with the bench scale study; and Pavel Islam, who fixed my laptop at a crucial stage of my study.  I would also like to thank Metro Vancouver for allowing me to work at the Annacis Wastewater Center, Delta. Special thanks to Ron Howell and Darlene Reigh, Metro Vancouver for their continuous support. My sincere gratitude to NSERC, Opus Dayton-Knight and the City of Abbotsford for the research funding.  Last, but not the least, I want to thank all my lab mates, friends, family, my parents and specially my husband for their endless support and undying encouragement. And thank you GOD for everything!      xxi  Dedication       To My Husband Wi ho   who   lov ,   ppo    n      i i    I wo l n‘   v n    h         Introduction  1  1 Introduction 1.1 Background Nitrogen (N) and phosphorus (P) are two essential nutrients playing important part in the global nutrient cycle involving all living forms. Nitrogen circulates through the global N-cycle while phosphorus is a non-renewable resource mined from phosphate rocks. Due to the high demand of phosphorus in industry and agricultural sector against limited supply, global phosphorus reserves are decreasing each year. While both nitrogen and phosphorus have very high demand as fertilizers, large amount of these nutrients are already present in the wastewater, which can be recovered, hence turning the wastewater into resource. Excess nutrients (P & N) in wastewater not only pose threat to the environment (causing eutrophication), they are also responsible for struvite nuisance and increased operational cost in wastewater treatment plants. Therefore, nutrient management in WWTPs is of primary concern. During the anaerobic digestion step in the sludge management process, dewatered sludge liquor or centrate is released in the digester and contains a very high amount of soluble ammonia and phosphorus. Centrate contains 500 mg/L to 1500 mg/L of ammonium-nitrogen (NH4-N) and 37 mg/L to 150 mg/L of phosphate-phosphorus (PO4-P) (Britton, 2002; Fattah, 2004; Hassan, 2013; Huang, 2003). Because of these high concentrations, centrate must be recycled back to the headwork of WWTPs, imposing additional nutrient loads on the plants. Almost 15 – 20% of ammonia load and up to 10% of phosphate in the influent of WWTPs come from centrate (Fux et al., 2006; Wild et al., 1997).  Among several wastewater treatment technologies developed to treat this side stream, struvite precipitation for P-removal and the anammox process for N-removal, have Introduction  2  become very popular with high removal efficiencies. Orthophosphate removal of over 90% can easily be achieved by the struvite precipitation process, while ammonia removal is only in the range of 4 to 20%,  leaving a huge amount of nitrogen load (Adnan, 2002; Booker et al., 1999; Fattah, 2004). On the other hand, the anammox process removes only nitrogen (over 90% of ammonia) but the final effluent is still rich in phosphate (Kosari, 2011; Wu, 2012). Instead of managing one nutrient at a time, a unified solution of managing both nutrients by combining anammox and struvite process is of great interest in the wastewater sector. A bench-scale study was conducted with synthetic feed (representing anammox effluent) as influent for a struvite precipitation process; the study resulted in 60 to 70 % PO4-P removal and 15 to 20% NH4-N removal, with a relatively higher (2 to 3 times) caustic consumption. In that study, pure struvite precipitated in the form of powder instead of pellets (Hassan et al., 2013). Several questions resulting from the bench-scale study by Hassan (2013), encouraged this follow-up pilot scale study; the possible outcome using on-site, centrate from WWTPs with fluctuating characteristics instead of synthetic feed. Possible results obtained from combining these two technologies in reverse order; and the possibility of producing high-quality struvite pellets, needed to be answered.   1.2 Research Objectives This pilot scale study was conducted at Annacis Wastewater Centre (AWC), Delta, BC, Canada. The goal was to manage the nutrients present in the Annacis centrate, combining struvite precipitation with a UniBAR-Anammox process, in two different sequences shown in Figure 1.1. Introduction  3          The objectives of this study were: • To combine struvite precipitation with Pre-UniBAR anammox and Post-UniBAR-anammox process, to remove and recover P and N • To recover struvite pellets for commercial use • To meet the caustic consumption challenge, through reduced chemical usage In order to meet the objectives, research questions were identified and experiments were conducted at the Annacis Wastewater Research Center over a period of one year.  1.3 Research Questions   What could be the potential of N-removal from centrate by Post-Struvite Anammox Process? Final Effluent Low P, Low N Combination 1: Pre-Anammox-Struvite Process Centrate  Influent High P & N  Struvite Precipitation with UBC Reactor UniBAR Anammox Process Struvite Effluent Low P, High N Final Effluent Low P, Low N Combination 2: Post-Anammox-Struvite Process Centrate  Influent High P & N  Struvite Precipitation with UBC Reactor UniBAR Anammox Process Anammox Effluent Low N, High P Figure 1.1: Pilot Scale study of combining Struvite precipitation and UniBAR-anammox process Introduction  4   How does the Struvite Effluent Feed affect the Anammox Process? Is there any adverse effect of the combination?  What could be the potential of P-removal and recovery from centrate by Post- Anammox Struvite Process?  How does the Anammox effluent feed affect the Struvite Process? Is there any adverse effect of the combination?  Is it possible to produce Struvite Pellets in both combinations? Also, is there any difference in the struvite pellets recovered from the Pre and Post Anammox Struvite Processes?    Literature Review  5  2 Literature Review Among different nutrients (Nitrogen, Phosphorus, Carbon, Potassium etc.) present in wastewater, Nitrogen (N) and Phosphorus (P) are the main nutrients of concern because of their high concentration and deleterious role in water pollution. On one hand, an excess amount of phosphorus and nitrogen pose threats to the environment, while on the other hand, these two are irreplaceable elements in many physiological and biochemical processes in all life forms.  2.1 Importance of Wastewater Nutrient Management 2.1.1 Environmental Concern Eutrophication is the major environmental concern resulting from nitrogen and phosphorus discharges into rivers, lakes, ponds and streams. These nutrients, in excess amount, are responsible for algal blooms and excessive levels of microorganisms and subsequent dissolve oxygen depletion in the receiving water bodies. It also increases turbidity, while decreasing the aesthetic values, due to excess biological productivity. As a result, this water may no longer be beneficial for drinking or recreation purposes. Among these two, phosphorus is the limiting nutrient and mainly responsible for eutrophication (Bitton, 2005; Schindler, 2006). Since both of these nutrients are present in wastewater, it is essential to remove excess N and P before discharging the effluent from WWTPs.  2.1.2 Stringent Regulations Because of the environmental concern, phosphorus and nitrogen concentrations in WWTP effluent have to meet stringent discharge regulations. In North America total Literature Review  6  phosphorus discharge limit ranges from 0.1 to 2 mg/L (Metcalf & Eddy et al., 2003). According to Canadian Water Quality Guidelines for the Protection of Aquatic Life in freshwater system, a total phosphorus of 0.035 to 0.1 mg/L triggers eutrophic conditions  and TP >0.1 mg/L triggers hyper-eutrophic conditions (CCME, 2004). Guideline values for un-ionized ammonia for the protection of aquatic life is 0.019 mg/L and for total ammonia-nitrogen varies from 0.02 to 189 mg/L depending on pH and temperature (CCME, 2010). Total ammonia values (in mg/L NH3) are shown in Table 2.1.  Table 2.1: Water quality guidelines for total ammonia for the protection of aquatic life (mg/L NH3)(CCME, 2010) According to the Guidelines for Effluent Quality and Wastewater Treatment at Federal Establishments, a total phosphorus (TP) of 1 .0 mg/L has to be maintained in the effluent Literature Review  7  before discharge (Federal Activities Environmental Branch, 1976). In different regions of Canada, phosphorus concentration discharge limits vary, based on the regional environmental conditions. For example, the city of Penticton, South Central, BC has a strict TP discharge limit of 0.25 mg/L from WWTPs, keeping in mind the growing agricultural sector (Britton, 2002). Different treatment technologies are applied in wastewater treatment plants to meet the rigorous discharge limits of N and P. 2.1.3 Problems in Wastewater Treatment Plants To deal with the wastewater nutrients, several biological nutrient removal (BNR) and enhanced biological phosphorus removal process (EBPR) plants are currently in use throughout the world. However, there are issues of operational problems like excess sludge production, phosphorus re-release during anaerobic digestion and struvite formation in piping and equipment, possibly causing costly shut downs. 2.1.3.1 Additional Nutrient Load From Dewatered Sludge Liquor or Centrate Biological phosphorus removal is done by utilizing Polyphosphate Accumulating Organisms (PAOs) to accumulate phosphorus in excess of their metabolic requirements; this stored polyphosphate is re-solubilized during anaerobic digestion (Jardin and Pöpel, 2001). Also, the breakdown of protein and bacteria causes high concentrations of  ammonia (Munch and Barr, 2001).  In one study, sludge digestion increased ortho-phosphate concentration by 38% (Jardin and Pöpel, 2001), whereas more than 80% of previously removed phosphorus in the BNR process was re-released after digestion, in another study (Mavinic et al., 1998). Literature Review  8  Various articles have reported that centrate can contribute 15-40% of total nitrogen loading to the WWTPs (Klein et al., 2013; Kosari, 2011; Mehrdad et al., 2013).  After dewatering the anaerobic sludge, this sludge liquor (centrate) is recycled back to the headworks of WWTPs, because of the high P and N content, as shown in Figure 2.1.  Figure 2.1 Dewatered sludge liquor or Centrate recycled to WWTP headworks adopted from (Munch and Barr, 2001) This additional nutrient loading from the side stream affects the plant performance, as well as increases operational cost. Hence, suitable treatment of centrate is required (Munch and Barr, 2001; Pitman et al., 1991). 2.1.3.2 Unintentional Struvite Formation Unintentional formation of struvite (essentially, a hardened scaling effect) in piping, digestion tanks pumps, valves, etc. causes major operational problems in many wastewater treatment plants (Ohlinger et al., 1998). High turbulent areas (i.e. pump impellers, pipe bends etc.)  and areas with high phosphate, magnesium, along with high pH (i.e. digested sludge liquor pipelines) are prone to struvite formation (Hassan, 2013; Jaffer et al., 2002; Ohlinger et al., 1999). Struvite precipitation damages pumping systems, causes plugging of piping and reduces the plant flow capacity. Annual costs for Literature Review  9  one mid-size treatment plant (25 MGD) surpassed 100,000 US dollars, due to the struvite nuisance (Doyle and Parsons, 2002).  2.1.4 Global Phosphorus and Nitrogen Cycle The biospheric cycle of N is different than the P cycle (Smil, 2000). Global N cycle consists of nitrogen in five major forms (NH3, NH4+, NO2-, NO3- and N2) and their inter transition (nitrogen oxidation state ranging from +5 to -3) (Kang, 2014). The simplified global nitrogen cycle is shown in Figure 2.2.  Figure 2.2: Nitrogen cycle (Environment Canada, 2001) When urea and other proteinaceous organic matter are decomposed by microorganisms, nitrogen present in those organic matters gets converted to ammonia, which is further oxidized to nitrites and nitrates. These nitrites and nitrates are used up by plant and animals for protein generation, which will eventually release ammonia back into the Literature Review  10  environment after the decomposition of dead plants and animals (Wu, 2012). On the other hand, the denitrification process converts these nitrites and nitrates into N2 gas, which is released back to the atmosphere. Beside this natural N cycle, the industrial fixation process known as Haber-Bosch is used for ammonia production, from this atmospheric nitrogen (Kang, 2014).  In the atmosphere, nitrogen is the main component of air (78% of volume in dry air), whereas phosphorus does not exist in a stable gaseous form but is found in the earth‘  crust, soils, sediments and water. P is the eleventh-most abundant mineral in the lithosphere (Smil, 2000). Mineralization, weathering, erosion, and runoff will transfer soluble and particulate P to the ocean, which is eventually deposited into the sediments, creating a one-way flow of inorganic P. Then again, organic P is cycled in land- and water-via living forms. Phosphates present in soils are converted to orthophosphates to become biologically available to plants and microorganisms; this moves up to the animals and human body through the food chain and at the end of the cycle, decomposition of dead microorganisms, plants and animals return a portion of the nutrient back into soil (Smil, 2000).  2.1.5 Supply and Demand of Phosphorus and Nitrogen Phosphorus (P) and Nitrogen (N), two essential nutrients, are of high demand globally. Natural calcium pho ph    o  v  io    o m ,  omm   i lly known    ―Pho ph     o k‖, is the source of phosphorus for the phosphate industry and is being depleted rapidly. Yearly extraction of phosphate (expressed as P2O5) is approximately 38 million tonnes globally (Driver et al., 1999).  Literature Review  11  By 2100, 20–35% (best case scenario) or 40–60% (worst case scenario) of global P reserves will be depleted (Van Vuuren et al., 2010). Also, this reserve is localized in some regions like Morocco, Russia and China (FAO, 2012; Mavinic, 2015; Smil, 2000). Along with declining P reserves, the quality of the extracted phosphates has become a matter of great concern, because of the heavy metal contamination (such as arsenic, cadmium, uranium, lead, mercury, nickel, chromium, copper and zinc), thus posing health risks (Driver et al., 1999; Smil, 2000). Also, the P content of extracted phosphates is decreasing approximately 4% every 5 years (Mavinic, 2015). In contrast, nitrogen is abundant in the atmosphere. Nitrogen (from air) is combined with hydrogen (mainly from natural gas) to produce ammonia in the Haber-Bosch Process (Aneja et al., 2008). Ammonia (NH3) is the basic nitrogen source used for N fertilizer. Beside the anthropogenic activity, biological nitrogen fixation of approximately 2 x 108 metric tonnes of N2/year is estimated globally (Bitton, 2005).  Nutrient (nitrogen, phosphorus as P2O5 and potassium as K2O) consumption as fertilizer globally, is expected to reach 194.1 million tonnes by 2016, at a rising demand rate of 3.5 percent per annum (1.3% for N and 6% for P) from 2012 to 2016. Worldwide supply, demand and the potential balance of Nitrogen and Phosphorus were forecasted by the Food and Agricultural Organization. Estimated values for 2016 are shown in Table 2.2 (FAO, 2012). Literature Review  12  Table 2.2: World supply, demand and potential balance of Nitrogen and Phosphorus Nitrogen (N) Estimated for 2016 (thousand tonnes) Phosphorus  (as P2O5) Estimate for 2016 (thousand tonnes) NH3 Capacity (as N) 181,458 H3PO4 Capacity 61,323 NH3 Supply Capability (as N) 158,463 H3PO4 Supply capability 49,835 N Other use 311,76 H3PO4 industrial demand 6,534 N Availability for fertilizer 127,287 H3PO4 available for fertilizer 43,301 N Fertilizer consumption 115,956 P fertilizer consumption/demand 45,012 Potential N Balance 11,332 Potential H3PO4 balance 3,781  2.1.6 Economic Considerations  There are several economic aspects of wastewater nutrient management. Recovered nutrients can be a suitable product for dealing with the current demand for nutrients in the industry and agricultural sector. Nutrient recovery can save chemical and operational cost in the treatment plants by reducing sludge handling cost, maintenance costs (due to unintentional struvite formation) and costly shutdown. Also, there is a potential for revenue earning from struvite product sale (Fattah, 2004; Huang, 2003; Shu et al., 2006).  Since P and N are of high demand in the fertilizer industry, recovering these nutrients in struvite pellet form is a good option which can be used as a slow release fertilizer. Along with phosphate and ammonia, magnesium is also present in struvite pellets and all these three nutrients are essential for plant growth. In Japan, produced struvite from wastewater was sold at around €245 Euro (approximately $230 USD) per tonne in 2001 (Ueno and Fujii, 2001). From other studies, a suggested value for struvite per tonne was mentioned as $198- $330 USD in Australia and $283 USD in UK (Doyle and Parsons, 2002; Munch and Barr, 2001), about 12-15 years ago. Also, because of higher purity and Literature Review  13  low heavy metal content, recovered phosphorus products are preferred over mined phosphate rocks in the phosphate and fertilizer industry (Driver et al., 1999). Approximately 0.63 million tons of phosphorus (as P2O5) could be harvested annually worldwide through struvite recovery from WWTPs, saving phosphate rock mining by 1.6%  of global demand (Shu et al., 2006). Phosphorus recovery also reduces sludge generation (up to 49%), leading to a considerable reduction in sludge handling costs (Woods et al., 1999). Around $120 CAD per day sludge handling cost was saved in a phosphorus recovery study at the Penticton, BC, Advanced WWTP, due to less polymer usage and savings in sludge shipping (Britton, 2002). Without recovery technology, the P removal process generated excess sludge in the form of chemical precipitates, incurring a cost of 15 million Euros per year in France for sludge handling (Paul et al., 2001). 2.2 Wastewater Nutrients Management Techniques With the most recent developments in nutrients removal and recovery methods incorporated in wastewater treatment plants (WWTPs), wastewater is now being considered as a resource rather than waste (Mavinic, 2015). Different physical, chemical, and biological nutrient removal methods are mentioned in this section.  2.3 Phosphorus Management  2.3.1 Physical Treatment Physical treatment options such as filtration for particulate phosphorus and membrane technologies (i.e. membrane bioreactors, tertiary membrane filtration, reverse osmosis Literature Review  14  for suspended and dissolved phosphorus removal) have shown promising results (Strom, 2006). 2.3.2 Chemical Treatment Because of the simplicity and reliability of the process, chemical precipitation with multivalent metal ion salts is used widely in wastewater treatment, to remove phosphorus by converting soluble phosphate to a particulate form (Woods et al., 1999). Popular methods for phosphorus recovery by chemical precipitation include calcium phosphate precipitation, aluminum and iron phosphates, struvite (magnesium ammonium phosphate) precipitation, membrane or ion exchange with precipitation etc. (Fattah, 2004; Hassan, 2013) 2.3.2.1 Calcium Phosphate Precipitation Usually Ca(OH)2 (Calcium hydroxide) is used to facilitate calcium phosphate precipitation in the form of Ca10((PO4)6)OH2 (Hydroxylapatite) at a pH greater than 10, as seen in equation (1)   10 Ca+ + 6 PO43- + 2 OH- ↔   10(PO4)6(OH)2 (1) But because of this high operating pH, it is important to adjust the pH of discharged wastewater. Also, sludge production and operation costs due to chemical addition are higher in this process, making it disadvantageous (Metcalf & Eddy et al., 2003). Phosphorus recovery as calcium phosphate was considered to be more promising. But the recovered calcium phosphate pellets, with the use of sand as seed crystals, could not Literature Review  15  match the phosphorus content level available in the high grade phosphate rocks (Driver et al., 1999).  2.3.2.2 Chemical Precipitation by Iron or Aluminum Iron salts such as ferric chloride, ferric sulphate, or ferrous sulphate are used for phosphate precipitation with iron (FePO4) at a minimum pH of 5.3, as per Equation (2)  Fe3+ + HnPO43-n ↔ F PO4 + nH+ (2) On the other hand alum is used for aluminum phosphate precipitation at pH above 6.3, as shown in Equation (3)  Al3+ + HnPO43-n ↔ AlPO4 + nH+ (3) An increase in chemical cost and sludge production, as well as possible decrease in  effluent pH, are considered as the disadvantages of these processes (Metcalf & Eddy et al., 2003). 2.3.2.3 Struvite Precipitation Process Precipitation of phosphorus in the form of magnesium ammonium phosphate (MAP) is popularly known as struvite precipitation, for phosphorus recovery. A white crystalline substance consisting of equimolar magnesium, ammonium and phosphate is named as struvite, or MAP (MgNH4PO4.6H2O) (Doyle and Parsons, 2002). Struvite, being the end product of struvite crystallization process, has commercial value as a slow release fertilizer because of its mineral composition (Mg, N and P) and high P2O5 content Literature Review  16  (Booker et al., 1999). Detailed discussions on struvite precipitation process are provided in Section 2.6. 2.3.2.4 P-Removal by Ion Exchange  Phosphate ions from tertiary wastewater can also be removed by membrane or ion exchange technologies, preceding precipitation (Fattah, 2004). Ion exchange resins, such as purolite, hydrotalcite and layered double hydroxides, have been successfully used for P-removal (Lv et al., 2008; Nur et al., 2013). The ion- exchange technique is a simple and economical process with less sludge production (Nur et al., 2013).   2.3.3 Biological Treatment Biological nutrient removal (BNR) and Enhanced Biological Phosphorus Removal (EBPR) are the biological phosphorus removal processes, where Polyphosphate Accumulating Organisms (PAOs) remove P by accumulating phosphorus in excess of their metabolic requirements, when subjected to alternating aerobic and anaerobic conditions. The 5-stage Bardenpho process, the Modified UCT process, and the Johannesburg process are commonly used BNR processes (Metcalf & Eddy et al., 2003). Candidatus Accumulibacter phosphatis is the bacterium considered responsible for Biological P removal (BPR) processes (Bitton, 2005). BPR reduces chemical usage cost as well as disposal cost of chemical sludge. Other concerns in the chemical precipitation process are the unacceptable concentration of coagulant cations (Al3+, Fe3+ etc.) in the effluent and  the increasing total dissolved solids in the receiving water, due to the chemical addition, affecting re-use (Barnard and Shimp, 2013; Paul et al., 2001). But the implementation of BPR requires a complex plant design (Morse et al., 1998). It is also Literature Review  17  responsible for increasing aeration requirement and formation of nuisance struvite within the solids piping, digesters, holding tanks, as well as inducing problems with dewatering in digested sludge  (Barnard and Shimp, 2013; Schauer, 2013). 2.4 Nitrogen Management 2.4.1 Physical Treatment 2.4.1.1 Gas Stripping Gas stripping (especially air) is a popular physical treatment method which removes volatile forms of nitrogen, like ammonia from wastewater based on the principle of ion equilibrium with ammonia and hydrogen ions shown in Equation (5)  NH4+  NH3+ H+ (5) Basic conditions (pH >7.0) and higher temperatures, encourage ammonia gas production, by shifting the equilibrium to the right (Wu, 2012). Air stripping takes place in aerated grit chambers, biological treatment reactors, or transfer channels or within stripping towers. In the stripping towers, gas-liquid contact is provided with the use of packing material, increasing the mass transfer coefficient of the process. However, air stripping is not an economic option because of the high aeration requirement and probable need for contaminated gas treatment (Metcalf & Eddy et al., 2003). Also, there is the additional cost of maintenance because of the scale formation at high pH, within these towers, needing a frequent acid wash (Reeves, 1972). Literature Review  18  2.4.1.2 Microwave Technique Microwave (MW) radiation is an alternative approach developed recently for the removal of ammonia nitrogen from wastewater. The formation of ammonia (NH3) from ammonium ion (NH4+) at high pH, following volatilization of the molecular ammonia (NH3) by MW radiation, is the basic mechanism of this novel process. Though the vital part in removal process is played by a thermal effect, non-thermal effects also contribute in the removal. A study done with MW application for removing high concentrations of ammonia present in coke-plant wastewater resulted in 93% of N-removal at pH 11 and MW power of 750W (Lin et al., 2009a).  MW technology has a faster and higher removal efficiency than a stripping method (Menéndez et al., 2002). Also, the decrease in investment and treatment cost due to the reduction in effluent water volume and better water quality after treatment, are considered as advantages of MW processes. However, the high energy consumption for converting electric energy to heat is the main disadvantage of this process  (Lin et al., 2009b). 2.4.2 Chemical Treatment 2.4.2.1 Breakpoint Chlorination Breakpoint chlorination can be used to remove ammonia from wastewater by adding chlorine to wastewater and oxidizing the ammonia-nitrogen to nitrogen gas. Monochloramine (NH2Cl) is formed when chlorine, in the form of hypochlorus acid (HOCl), reacts with ammonia at 1:1 molar ratio. Further oxidation reaction forms dichloramine. Breakpoint reaches at chlorine to ammonia-nitrogen molar ratio of 1.5:1 as Literature Review  19  the chloramines get oxidized and N2 is released into the atmosphere. The overall reaction is shown in Equation (6)   NH4+ + 1 5 HO l → 0 5 N2 + 1.5 H2O + 2.5 H+ + 1.5 Cl- (6) This chemical process is very fast but high chemical cost and potential toxic effect on aquatic life from residual chlorine creates some disadvantages (Metcalf & Eddy et al., 2003)  2.4.2.2 Struvite (MAP) Precipitation As mentioned earlier in Section 2.3.2.3, chemical precipitation in the form of magnesium ammonium phosphate (MAP), commonly known as struvite (MgNH4PO4.6H2O), is a popular method already applied at full scale, for ammonia-nitrogen removal and recovery from wastewater, along with phosphorus. Detail descriptions are given in Sections 2.6.  2.4.2.3 Selective Ion Exchange Selective ion exchange by natural zeolite clinophlolite has been applied to remove N from wastewater. To prevent fouling of zeolite, filtration is added before ion-exchange. Regeneration of the zeolite is also required in this process (Sedlak, 1991). Ammonium nitrogen removal efficiency as high as 95% with good control over effluent quality are the usual advantages, while a major disadvantage of this ion-exchange technique is the high cost associated with chemical regeneration (Lahav and Green, 1998).    Literature Review  20  2.4.3 Biological Treatment 2.4.3.1 Conventional Nitrification and Denitrification  Conventionally biological nitrogen removal from wastewater is achieved by two processes, nitrification and denitrification. Nitrification is a two-step process where ammonia is oxidized into nitrates by chemoautotrophs and then nitrates get converted to nitrogen gas in the denitrification process, by heterotrophic bacteria.   2.4.3.2 Nitrification The two phase nitrification process consists of an ammonia oxidation reaction, followed by nitrite oxidation reaction, under aerobic conditions. In the first step, ammonia-oxidizing bacteria (AOB), such as Nitrosomonas oxidize the ammonia and ammonium present in wastewater into nitrites, as seen in Equation (7) (Bitton, 2005; Metcalf & Eddy et al., 2003).  NH3 + 1.5 O2 → NO2- + H+ + H2O (7) In the second step, nitrite-oxidizing bacteria (NOB), such as Nitrobacter, further oxidize nitrite into nitrate, as shown in Equation (8) (Bitton, 2005; Metcalf & Eddy et al., 2003).  NO2- + 0.5 O2 → NO3- (8) Dissolved oxygen (DO) levels, temperature, pH, ammonia/nitrite concentration, and BOD5/TKN ratio are the controlling factors for the biological nitrification process. Aerobic conditions, with a DO level of 2 mg/L or above must be maintained in the reactor. According to stoichiometric calculations, 4.6 mg O2 is needed to oxidize 1 mg of ammonia. Temperature within a range of 8-30°C helps the biological kinetics, with an Literature Review  21  optimal temperature range of 25-30°C. Nitrification is an alkalinity consuming reaction where 7.14 g of alkalinity as calcium carbonate (CaCO3) is consumed per 1 mg of ammonia oxi iz    Thi   iologi  l p o       op     pH≤ 6 0  S   i i n   lk lini y h    o be present in the system to maintain the optimum pH range of 7.5 to 8.5, for the AOB and NOBs (Bitton, 2005).  2.4.3.3 Denitrification Denitrification is an anoxic biological process where nitrates and nitrites generated in nitrification process are reduced to nitrogen gas (N2) in multiple steps shown in Equation (9) (Bitton, 2005)  NO3- → NO2- → NO → N2O → N2 (9) Reduction of Nitrite and nitrates are shown in Equations (10) and (11) (Wu, 2012).   2NO3- +10 H+ + 10e- = N2+2OH-+ 4H2O   (10)  2NO2- +6 H+ + 6e- = N2+2OH-+ 2H2O   (11) Facultative heterotrophic bacteria such as Psuedomonas, Bacillus, Spirilum, Hyphomicrobium, Agrobacterium, Rhizobium etc. are responsible for denitrification (Bitton, 2005). From the above equations, it can be seen that denitrifying bacteria need an electron donor for this reduction reaction. Organic compounds such as acetic acid, citric acid, methanol, ethanol etc. act as electron donors.  In the absence of sufficient organic compounds in wastewater, external carbon sources are added to complete the denitrification reaction. Methanol is popular as a carbon source because of its relative lower cost. Denitrification, using methanol, is illustrated in Equation (12)  Literature Review  22   6 NO3- + 5 CH3OH → 3 N2 + 5 CO2 + 7 H2O + 6OH- (12)  CH3OH/NO3- ratio needs to be greater than 3 for complete denitrification. Nitrate concentration, anoxic condition, presence of organic carbon, pH and temperature are the controlling factors for this process. Temperatures of 35-50°C, pH range of 7.0-8.5 and dissolved Oxygen (DO) < 0.2-0.5 mg/L are the optimal conditions (Bitton, 2005). From stoichiometric calculation it is found that 3 to 3.6 mg alkalinity is produced per mg of nitrate reduction reaction during denitrification (Bitton, 2005; Wu, 2012). Common biological nitrogen removal processes incorporated in wastewater treatment plants are the Modified Ludzack-Ettinger (MLE) process, the 4-stage Bardenpho process and the step feed process, with a typical design SRT of 10 to 20 days at 10 °C, or 4 to 7 days at 20°C (Metcalf & Eddy et al., 2003). 2.4.3.4 Anaerobic Ammonium Oxidation (ANAMMOX) A nov l mi  o i l p o     n m   ―An mmox‖ h       n ly g in   pop l  i y in the wastewater sector for N-removal from wastewater containing high nitrogen concentration (Strous et al., 1997). This process is more advantageous over the conventional nitrification-denitrification process, as operational costs are reduced up to 90% (Jetten et al., 2001) since the oxygen requirement is less (saves up to 63% of Oxygen) and no external carbon source is needed (Wu, 2012). Also, the conventional nitrification– denitrification process is not suitable for dewatered sludge liquor (centrate) due to the high amount of CO2 being released. Besides, another greenhouse gas, nitrous oxide production, is expected to be half of that produced in conventional nitrification-Literature Review  23  denitrification process, since only half of the ammonia is oxidized to nitrite in anammox process (Hassan, 2013). Details on the Anammox process are discussed in Section 2.5. 2.5 Anammox Process for N-removal 2.5.1 Mechanism of Anammox Process  The possible presence of bacteria that could produce nitrogen gas from ammonium was first mentioned in 1977 by Broda, when he hypothesized that two kinds of lithotrophs were missing in nature based on Gibbs free energy calculations (Broda, 1977). Mulder et al. (1995) discovered a novel biological process of oxidizing ammonia into nitrogen gas, while studying denitrifying fluidized bed reactor behaviour for treating the effluent of a methanogenic reactor. This evidence of ammonia being oxidized under anaerobic condition triggered  h  n m  ―An   o i  Ammoni m Oxi   ion  An mmox)‖ (Mulder et al., 1995). The anammox process equation, with nitrite as an electron acceptor, was proposed by van de Graaf et al. in 1995. The reaction shown is in Equation (13)  NH4+ + NO2- = N2 + 2H2O (13) Later on, from stoichiometric mass balance, a molar ratio of ammonia and nitrite in anammox process was found to be 1:1.32 under anoxic conditions, as presented in Equation (14) (Strous et al., 1998). NH4++1.32NO2-+0.066HCO3-+0.13H+=1.02N2+0.26NO3-+0.066CH2O0.5N0.15+ 2.03H2O (14) Literature Review  24  Anammox bacteria are active players in the global nitrogen cycle, as shown in Figure 2.3.  Figure 2.3 :Anammox bacteria in the global Nitrogen cycle adopted from  (Trimmer et al., 2003) Candidatus Brocadia anammoxidans, Candidatus Kuenenia stuttgartiensis and Candidatus Scalindua sorokinii etc. are some anammox bacteria species identified by their 16rRNA sequences in wastewater and marine environment (Jetten et al., 2001; Penton et al., 2006). Slow growing anammox bacteria have an average doubling time of 10.6 days (Jetten et al., 2001). These red-coccoid, anammox bacteria have diameter of less than 1 µm (Van Niftrik et al., 2004). Van de Graaf et al. proposed the first metabolic pathway of anammox considering hydroxylamine (NH2OH) as a critical intermediate of nitrite reduction (Van de Graaf et al., 1995).  A similar mechanism theory was postulated by Jettan et al. (2001) through 15N-labelling experiments in Candidatus Brocadia anammoxidans species (Figure 2.4) where nitrite (electron acceptor) was reduced to hydroxylamine (NH2OH) and reacted with ammonium (electron donor), producing hydrazine (N2H4). Dinitrogen gas was the final end product (Jetten et al., 2001).  Literature Review  25   Figure 2.4: Mechanism of Anammox process adopted from (Jetten et al., 2001) In another study with Candidatus Kuenenia stuttgartiensis species, nitric oxide (NO) was suggested to be the intermediate for nitrite reduction  instead of hydroxylamine (Strous et al., 2006). Therefore, hydrazine was assumed to be an important intermediate for the anammox process which was oxidized by HZO (equivalent to hydroxylamine-oxidoreductase-like protein) present inside anammoxosome of the anammox bacteria cells (Jetten et al., 2001; Strous et al., 2006). 2.5.2 UniBAR-Anammox Reactor Unified Biological Aerated Reactor (UniBAR) is a single-stage, biological reactor where partial nitrification and anammox processes can take place to remove ammonia from wastewater, thus reducing the footprint and start up time of reactors (Prongineer Ltd., 2011). The reason behind adopting partial nitrification along with the anammox process is that wastewater does not always contain the required Nitrite to Ammonia molar ratio of 1.32 (Strous et al., 1998; Zhang et al., 2008). To achieve this nitrite/ammonia ratio, several processes like Partial Nitrification-Anammox, Sharon-Anammox, and the Literature Review  26  CANON process have been used (Khin and Annachhatre, 2004; Wu, 2012; Zhang et al., 2008).  In CANON (Completely autotrophic nitrogen removal over nitrite) process, where partial nitrification and anammox process are integrated into one reactor, the AOB take oxygen to oxidize ammonium to nitrite (Partial Nitrification Equation 15); the anammox bacteria convert nitrite and the ammonium remained in the reactor to nitrogen gas under anaerobic conditions (Anammox process Equation 16). Equation (17) presents the overall CANON process reaction.   NH4+ + 1.5O2      NO2-+ 2H++H2O (15)  NH4+ + 1.32NO2-+0.13 H+      1.02N2+0.26NO3-+2H2O (16)     NH4+ + 0.85O2      0.44N2+0.11NO3-+ 1.08H++1.43H2O (17) Dissolved oxygen in the reactor  needs to be less than 0.5 g/L to facilitate anammox growth, while inhibiting NOB (Khin and Annachhatre, 2004; Kuai and Verstraete, 1998; Strous et al., 1997) This autotrophic process saves 63% of oxygen and 100% of carbon sources, compared to conventional nitrification and denitrification processes (Kuai and Verstraete, 1998).  Also there is no CO2 gas emission in the combined process, as it gets consumed by the autotrophic bacteria (Khin and Annachhatre, 2004). The advantages of the UniBAR-anammox process are the capability of bio-augmentation, savings in space energy and capital cost, flexibility in process operation (batch/continuous) and less start-up time (Prongineer Ltd., 2011). Literature Review  27  2.5.3 Key Factors for Controlling UniBAR-Anammox Process Since the UniBAR-Anammox process is a one stage reactor, accommodating partial nitrification and anammox process, factors such as pH, temperature, DO and nitrite accumulation need to be tightly controlled to facilitate AOB and Anammox bacteria growth, while suppressing the NOB. 2.5.3.1 Dissolved Oxygen At oxygen limiting conditions, AOB and NOB both compete for oxygen. Dissolved oxygen less than 0.4 mg/L, with a high ammonium environment, favours the growth of AOB over NOB, as NOB gets washed out (Schmidt et al., 2003; Sliekers et al., 2005). By providing intermittent aeration, nitrite produced by AOB, can be reduced by Anammox activity rather than being oxidized by NOB (Kang, 2014). Although anammox activity is completely inhibited by the presence of oxygen, it is possible to combine partial nitrification and the anammox process within one reactor, since the inhibition of oxygen is reversible (Strous et al., 1997). For a continuous, anammox culture reactor, a DO level below 0.2 ppm was preferable (Jung et al., 2007). In two different studies with a one stage anammox process, the DO level was maintained below 0.3- 0.5 mg/L (Kang, 2014; Wu, 2012).   2.5.3.2 pH pH and temperature controls the equilibrium between NH4+/NH3 and NO2-/ HNO2. At a constant temperature with increasing pH (7.5-8), AOB growth rate and activity is encouraged over NOB, due to the increase in ammonia concentration. Also, the nitrification rate decreases below pH 7.0 (Hellinga et al., 1999; Van Hulle et al., 2010). Literature Review  28  The optimal pH range for Anammox was found to be 6.7 - 8.3 (Strous et al., 1999). In a pilot-scale (400 L) CANON process, SBR operation with centrate feed, a pH set point of 6.0 resulted in an average N-removal over 90% (Wu, 2012).  2.5.3.3 Temperature Mass transfer, chemical equilibrium and the growth rate of AOB and NOB are influenced by temperature (Van Hulle et al., 2010). Temperature above 25 ºC increases AOB growth over NOB, while temperatures higher than 40ºC causes deactivation (Hellinga et al., 1999). The optimal temperature for AOB was found to be 35ºC and for NOB 38ºC (Grunditz and Dalhammar, 2001). For anammox systems, temperatures of 30 to 40ºC have been reported to be optimum, with highest activity at 37ºC (Egli et al., 2001; Strous et al., 1999). Other studies have also worked in moderate to low temperature ranges (11 - 28ºC), and showed some anammox activity (Egli et al., 2001; Isaka et al., 2007; Wu, 2012). 2.5.3.4 Nitrite Accumulation Nitrite is an essential and critical element in the anammox process. Nitrite produced by AOB is utilized, along with ammonia, by the anammox bacteria to produce nitrogen gas. But at the same time, excess amount of nitrite in the system is toxic to anammox bacteria and inhibits the process. However, the inhibitory concentration of nitrite varied in different studies. Short term inhibition was observed at 60 mg/L NO2-N (Bettazzi et al., 2010) while complete inhibition was reported at 100 mg/L NO2-N in a SBR system (Strous et al., 1999) and at185 mg/L NO2-N in RBC system (Egli et al., 2001). In contrast, only 50% activity loss was observed at nitrite concentrations as high as 350 Literature Review  29  mg/L NO2-N (Dapena-Mora et al., 2007). Other studies also reported similar higher NO2-N tolerance level in the anammox process (Cho et al., 2010; Kimura et al., 2010). Along with the inhibitory concentrations of NO2-N, there were differences in the inhibitory effects; some authors reported reversible effect, while other authors stated irreversible inhibition. In order to figure out the reason behind this contradiction, another study was performed to determine the effect of nitrite inhibition on the anammox process. This study identified that the aforementioned literature values resulted from different determination methods and biomass in different aggregation states, showing severe inhibition in case of suspended and flocculent biomass, compared to granular biomass (possibly due to the outer layer of the biofilm protecting the inner core). At the end of the several manometric batch tests, the authors of this study agreed with the higher NO2-N tolerance level, concluding that the IC50 of 350-400 mg/L NO2-N, in case of biofilm or granular sludge, can be regarded as an accurate and relatively situation independent value (Lotti et al., 2012).  2.5.3.5 Ammonium Concentration Different experimental studies have been conducted to determine the inhibitory ammonium concentrations on the anammox process. While one study identified no effect up to 1000 mg N/L in a continuous SBR operation (Strous et al., 1999), another study reported 50% inhibition at 770 NH4+ - N/L resulting from batch tests (Dapena-Mora et al., 2007). This conflict might have occurred from the difference in the experimental conditions and methods. To better understand the substrate (ammonium) inhibition effect, another research work was undertaken which confirmed that ammonium had no inhibitory effects, whereas free ammonia inhibited the anammox activity at a pH higher Literature Review  30  than 7.6 (Puyol et al., 2014). Free ammonia, as low as 13–90 mg/L, was found to be toxic to organisms (Waki et al., 2007). Another study showed that the free ammonia levels in anaerobic condition with non-acclimated biomass, encouraged the degree of nitrite build-up. However, once the biomass got acclimated, there was no inhibitory effect on the ammonium or nitrite oxidation by free ammonia levels as high as 40 mg NH3-N/L (Turk and Mavinic, 1989).  2.5.4 Application of Anammox Technology in WWTPs The anammox process is suitable for wastewater with a high ammonia load and low carbon/nitrogen ratio. Several bench and pilot scale studies with centrate, landfill leachate and coke-oven wastewater have resulted in successful N-removal by the anammox process (Wu, 2012). In the last 20 years, full-scale application of this technology has gained a lot of interest. The first full-scale (70 m3) SHARON-ANAMMOX process was built in Rotterdam WWTP, Netherlands in 2002 for centrate treatment with a design load of 500 kg-N/d (7.1 kg-N/m3/d) (van der Star et al., 2007). This plant achieved over 95% of NH4-N removal (Friedlander and Auger, 2004). In Taiwan, a full-scale, landfill-leachate treatment plant (average flow rate 304 m3/d) has been operational since 2006, with coexisting partial nitrification, anaerobic ammonium oxidation and denitrification processes. The combined partial nitrification and anaerobic ammonium oxidation process removed 68% of the total nitrogen (TN) (Wang et al., 2010).  Literature Review  31  2.6 Struvite Process for P-removal 2.6.1 Struvite Chemistry Phosphorus recovery as Struvite or MAP (MgNH4PO46H20) has become very popular recently in the wastewater sector. The simplified general reaction for struvite chemistry is shown in Equation (18) (Doyle and Parsons, 2002) Mg2++NH4++PO43-+6H2O↔MgNH4PO4.6H2O (18) With a molar ratio of magnesium, ammonium and phosphate of 1:1:1, in the struvite crystal. Nucleation and crystal growth  are two stages identified in the struvite precipitation process (Doyle and Parsons, 2002). Supersaturation ratio (SSR) controls the nucleation while crystal growth is controlled by mixing energy (Ohlinger et al., 1999). After the struvite crystal precipitation, hydrogen ions are released in solution, reducing the reactor pH (Hassan, 2013). Therefore, caustic is added externally to maintain the desired pH in the reactor, or CO2 can be stripped (Fattah et al., 2008; Mavinic, 2015). 2.6.2 Fluidized Bed UBC-Crystallizer for Struvite Precipitation Process Struvite crystallization, with fluidized bed reactors have been used for nutrient recovery projects at UBC since 1999, and the technology was patented in 2009 (Koch et al., 2011). By adding caustic and magnesium externally, the desired molar ratio of Mg:N:P of 1:1:1 is achieved inside the reactor, to facilitate struvite nucleation and subsequent struvite growth over time. Fluidization of the particles, along with sufficient turbulence, needs to be maintained. The UBC crystallizer has four column sections with an injection port at the bottom. Over 90% of phosphorus recovery, as struvite, is achieved using this reactor Literature Review  32  (Adnan, 2002; Fattah, 2010, 2004; Huang, 2003). Detail description of the reactor is discussed in Section 3.4.1. This technology is licensed to the Ostara Corporation, Vancouver, BC, Canada. 2.6.3 Key Factors for Controlling Struvite Precipitation Process There are several factors affecting the struvite formation such as pH, SSR, temperature, mixing energy, molar ratios etc. 2.6.3.1 Solubility Product and Supersaturation Ratio Solubility product (Ksp) is the equilibrium constant of a reaction that controls the precipitation process. It is popularly expressed as pKsp (-log Ksp) (Fattah, 2004). Instead of a particular pKsp value, slightly different values have been reported in the range of 12.6 to 13.8 for struvite (Dastur, 2001).  In recent years, supersaturation ratio (SSR) has become more popular to indicate the struvite formation potential which can be calculated using Ksp, as shown in Equation (19) (Wilson, 2013). However, to get a simple and quick estimation, SSR is also calculated using the conditional solubility product, from Equation (20) (Britton, 2002; Fattah, 2010; Hassan, 2013).      [{    }{    }{     }    ]     (19)             (20) Where, Ps=Conditional solubility product = [Mg2+][NH4+][PO43-] [ ] denoting concentration in moles per liter, Pseq= Conditional solubility product at equilibrium Literature Review  33  At equilibrium state, SSR equals to 1. Struvite precipitation occurs under supersaturated condition (SSR > 1) until the equilibrium is reached again, whereas struvite dissolution takes place in under-saturated conditions (SSR < 1). Struvite reactor pH needs to be controlled to maintain desired SSR of 1.0 to 5.0, in order to achieve the highest amount of phosphorus recovery as struvite (Hassan, 2013).  2.6.3.2 pH pH is one the key factors in struvite crystallization process controlling struvite solubility. Struvite precipitation takes place in alkaline conditions, where the rate of struvite crystallisation increases with increasing pH. For effective P-removal, a pH value of greater than 8.5 is suitable (Stratful et al., 2001) until a pH of 9.8, after which ammonia from water volatilises into free ammonia gas (NH3). As a result, the N: P molar ratio decreases, affecting struvite formation (Booker et al., 1999). The optimum operational pH for P- recovery varies with wastewater characteristics (Stratful et al., 2001). A number of studies reported an operational pH in the range of 8.0 to 9.0, successfully recovering more than 80% phosphorus and even higher (Booker et al., 1999; Jaffer et al., 2002; Munch and Barr, 2001). In contrast, other studies at UBC achieved over 90% phosphorus recovery, at a lower pH range of 7.3 to 7.5 with the help of a better mouse trap (Adnan, 2002; Fattah, 2004; Tweed, 2009).  2.6.3.3 Temperature Temperature affects the struvite solubility and crystal morphology (Durrant et al., 1999) .Struvite solubility increases with an increase in temperature from 10ºC to 50ºC, and then starts to decrease (Aage et al., 1997; Doyle and Parsons, 2002). In another study, struvite Literature Review  34  formation was found to be higher at 10ºC than at 20ºC (Adnan, 2002). Also, at higher temperatures (64ºC),  struvite morphology changes, affecting solubility (Doyle and Parsons, 2002).  2.6.3.4 Turbulence Turbulence or mixing energy helps in CO2 stripping from wastewater increasing the pH. Also, turbulence causes particle collision, resulting in better struvite formation. Struvite particle shapes are affected by the shear gradient of turbulence, producing compact crystals at high turbulence, while elongated crystals at low turbulence (Ohlinger et al., 1999). However, crystal breakage can be a concern when the mixing energy is too high (Durrant et al., 1999). In some studies, the Reynolds number (Re) calculated from upflow velocities in a fluidized bed reactor, has been used as a guideline of turbulence (Adnan, 2002; Fattah, 2004; Huang, 2003). 2.6.3.5 Molar Ratios For struvite precipitation processes, N: P and Mg: P molar ratios are critical controlling factors. Typically, the molar concentration of ammonium is higher than that of phosphorus in wastewater, which encourages P-removal as relatively pure struvite (Munch and Barr, 2001; Stratful et al., 2001). Again, Mg being the limiting factor , the amount of P-recovery is influenced by the Mg:P molar ratio (Stratful et al., 2001). A molar ratio of 1.05:1.00 achieved 95% P recovery from centrate (Jaffer et al., 2002), while another study mentioned a higher molar ratio of 1.30 : 1.00 for high P recovery as struvite (Munch and Barr, 2001). Because of the low molar concentration of magnesium usually found in wastewater, it needs to be added externally, most often as MgCl2. Literature Review  35  2.6.3.6 Presence of Impurities Presence of foreign ions such as calcium, carbonates, acetate and organic acids increases the solubility of struvite (Durrant et al., 1999; Ohlinger et al., 1998). Also, due to the impurities present, complex ions might form in the solution, increasing the solubility of struvite. Formation of magnesium phosphate complexes, reduces availability of magnesium and phosphate ion concentration for struvite formation (Ohlinger et al., 1998). 2.6.4 Application of Struvite Technology in WWTPs Wastewater treatment plants in several countries have implemented the struvite technology for phosphorus recovery. Shinji East Clean Centre, Japan earned 27,000 yen per tonne, by selling struvite products as fertilizer (Ueno and Fujii, 2001).  Unitika Ltd. Of Japan have been successfully running full-scale, MAP reactors and selling the struvite    ―G   n MAP II‖     iliz    (Munch and Barr, 2001). In Canada, full scale application of this technology has been successfully implemented by Ostara, Inc. at WWTPs in Saskatchewan and Alberta. Ostara also operates nutrient recovery facilities throughout the USA (such as in Wisconsin, Oregon, Pennsylvania, Virginia states) and Europe (Slough, UK) as well. The O     ‘  P   l® P o     is well known for phosphorus removal (up to 90%) and ammonia removal (of 40%) from centrate. Produced struvite is marketed as Crystal Green®, an environment friendly, slow-release  fertilizer (Ostara, 2014). The technology itself, is licensed directly from UBC (Koch et al., 2011). Materials and Methods  36  3 Materials and Methods 3.1 Project Outline  A pilot-scale study was conducted at the Annacis Wastewater Centre (AWC), Delta, BC to remove and recover phosphorus and nitrogen from dewatered sludge liquor or centrate, combining struvite precipitation with UniBAR-Anammox process. This UBC Master project was under study for one year.   Among the five Metro Vancouver wastewater treatment plants, the Annacis Wastewater Treatment Plant (AWWTP) is the largest, serving over a million residents. A simple process flow diagram of the plant is shown in Figure 3.1.  Figure 3.1:  Process flow diagram of AWWTP Materials and Methods  37  In the solids handling phase, anaerobically digested sludge is dewatered with centrifuges to 30% total solids and 70% of sludge liquor (Metro Vancouver, 2008). This sludge liquor or centrate is returned to the headworks, due to the high concentration of N and P. There is a supply line of this centrate from AWWTP to the AWC research hall, with a flow rate of 50 L/m and pressure of 350 kPa.    In the first part of the project, background studies were done with centrate feed to the struvite and anammox reactor separately, to determine the P and N removal efficiency. In the second part of the project, two possible combinations were studied by combining struvite process with pre and post anammox processes. The removal efficiencies of these combined processes were then compared with the background data. 3.2 Influent (Centrate) Characteristics Centrate or dewatered sludge liquor from Annacis wastewater treatment plant was used as the process influent. At AWC, centrate was first stored in a 5500 L tank, for at least 2 days, to facilitate solids settling; then the centrate supernatant was transferred into another 5500 L tank, used as the feed tank for the study.  The storage tanks were filled once or twice a week with fresh centrate. As a result, centrate characteristics were not always constant during the study.  Since P and N are the nutrients of concern in centrate, their variation throughout the project period is shown in Figures 3.2 and 3.3.  Materials and Methods  38   Figure 3.2: Ammonia-Nitrogen variation in centrate   Figure 3.3: Ortho-Phosphate variation in centrate It can be seen from the graphs that ammonia-nitrogen concentrations went below 600 mg/L and ortho-phosphate below 100 mg/L in April-May and again in mid Jul-mid Aug 2014 (red circled), when the centrate got diluted with DAF subnatant before coming to the research hall. This fluctuation also affected the reactor performances (discussed later). 02004006008001000120011-Jan-14 2-Mar-14 21-Apr-14 10-Jun-14 30-Jul-14 18-Sep-14 7-Nov-14 27-Dec-1415-Feb-15NH4-N (mg/L) Ammonia-Nitrogen Concentration in Centrate 02040608010012014016018011-Jan-14 2-Mar-14 21-Apr-14 10-Jun-14 30-Jul-14 18-Sep-14 7-Nov-14 27-Dec-14 15-Feb-15PO4-P (mg/L) Ortho Phosphate Concentration in Centrate Materials and Methods  39  3.3 Process Combinations 3.3.1 Combination 1: Pre-Anammox-Struvite Process A background study was done, with centrate feeding to the struvite and anammox reactor separately, then in the combination step, centrate as influent was fed into the struvite column first, to remove and recover phosphorus along with a small percentage of ammonia-nitrogen. This low-P & high-N struvite effluent was fed to the anammox reactor for N removal. In the combined process, the main focus was on the anammox reactor behaviour, since the influent for this anammox reactor now changed from centrate to struvite effluent (indicated by the red box) in Figure 3.4.    Struvite         Final Effluent Low P, Low N Struvite Effluent Low P, High N Struvite Precipitation with UBC Reactor UniBAR Anammox Process Centrate  Influent High P & N  Anammox Effluent Low N, High P Struvite Effluent Low P, High N Centrate  Influent High P & N Step 1: Background Study with Centrate Feed Step 2: Combined Process Centrate  Influent High P & N  Struvite Precipitation with UBC Reactor UniBAR Anammox Process Figure 3.4: Combination 1 (Pre-Anammox-Struvite Process) Materials and Methods  40  3.3.2 Combination 2: Post-Anammox-Struvite Process After completing the background study with centrate in step 1, two processes were combined in step 2. Centrate was the main influent feeding into the anammox reactor for N-removal while a post-anammox struvite column was setup to remove and recover mainly P with a small amount of N. In the second combination, the main focus was on the struvite process behaviour, since the influent for this struvite column changed from centrate to anammox effluent (indicated by the blue box) in Figure 3.5.             Struvite Precipitation with UBC Reactor UniBAR Anammox Process Step 1: Background Study with Centrate Feed Struvite Precipitation with UBC Reactor UniBAR Anammox Process Centrate  Influent High P & N  Centrate  Influent High P & N  Struvite Effluent Low P, High N Centrate  Influent High P & N  Anammox Effluent Low N, High P Final Effluent Low P, Low N Anammox Effluent Low N, High P Step 2: Combined Process Figure 3.5: Combination 2 (Post-Anammox-Struvite Process) Materials and Methods  41  3.4 Experimental Set up 3.4.1 Struvite Reactor Setup The main component of the struvite precipitation process setup was the UBC crystallizer or struvite column. An external clarifier was attached to it for recycle. Storage tanks for caustic and magnesium feed, pumps for centrate feed, recycle line and magnesium feed, and a pH controller for caustic feed were also needed.   3.4.1.1 Struvite Reactor Design A fluidized-bed, UBC crystallizer was used for the struvite precipitation process, consisting of  an ‗Inj   ion po  ‘     h   o  om,  ollow    y ‗H  v    Zon ‘, ‗A  iv  Zon ‘, ‗Fin   Zon ‘  n  ‗ l  i i  /S    hopp  ‘     h   op with increasing diameter. This variation in diameter, with increasing height, facilitated turbulent mixing and helped to separate the fluidized particles by size. For crystal growth, higher turbulence was needed at the harvest zone (Ohlinger et al., 1999). Once the particles grew larger, they could move down the reactor, overcoming the high upflow velocities (Fattah, 2004). The crystallizer was made of clear PVC piping and a pH probe was installed in the active zone, which was connected to the pH controller to maintain the desired pH in the reactor. Injection port The bottom part of the reactor was called the injection port, where the centrate feed and recycle feed returning from the external clarifier were mixed with the caustic and magnesium feeds. A high supersaturation ratio was achieved here, due to the coincident injection points of chemical feed lines (Fattah, 2004).  Materials and Methods  42  Figure 3.6 shows the injection port of the struvite column.   Figure 3.6: Injection port of pilot scale UBC crystallizer Harvest Zone The harvest zone above the injection port had two ball valves to isolate this part, while harvesting struvite pellets and cleaning the injection port. Active Zone 1.5 inch (3.81 cm) diameter active zone above the harvest zone had a pH probe installed to monitor and maintain the reactor pH. There was an isolation valve to separate this zone, if needed. Materials and Methods  43  Fines Zone On top of the active zone, there was a 3 inch (7.62 cm) diameter section of fines zone. It provided room for the expanded fluidized bed particles. Clarifier/Seed hopper The top-most section was of 7.5 inch (19.05 cm) inside diameter with a height of 15 inch (38.1 cm). Due to low upflow velocity in this section, fine particles were captured inside the reactor and prevented from being washed out. There were two overflow outlets at the side of the seed hopper. The main overflow at 12.5 inch (31.75 cm) water depth and the backup overflow line at 14 inch (35.56 cm) water depth in this section provided the pathway for struvite effluent flowing into the external clarifier. Section dimensions with upflow velocities and Reynolds numbers (at 25  ) are shown in Table 3.1.   Table 3.1: Struvite column design values Sections Length Inside diameter Area Volume Flow rate Upflow velocity* Reynolds Number Re* HRT   cm cm cm2 L L/min cm/min   min Harvest 53.34 2.54 5.07 0.27 2.04 402.60 1909.24 7.21         Active 60.96 3.81 11.40 0.70 178.93 1272.82 fines 60.96 7.62 45.60 2.78 44.73 636.41 seed hopper 38.10 19.05 285.02 10.86 7.16 254.56 Below harvest zone (Injection port included) 19.05 2.54 5.07 0.10     Total  232.41     14.70         *Upflow velocity and Reynolds number calculations are given in Appendix A Materials and Methods  44  3.4.1.2 External Clarifier for Struvite Column Effluent from the struvite reactor was, at first, captured into the square pyramidal shaped external clarifier and then recycled back to the struvite column. Since the fine particles and suspended solids settled in the clarifier, a relatively clear final effluent could pass to the drain. Total clarifier volume was 53.5 L, with a water holding capacity of 46.5 L. Clarifier dimensions are shown in Figure 3.7.  Figure 3.7: External clarifier of struvite column At the bottom of the clarifier there was an outlet for the recycle line, while an effluent overflow line going to the drain was set at the top. A level switch set inside the clarifier was connected to the recycle pump, to ensure the immediate shutdown of the pump if the water in the clarifier accidentally drained out.    14" (35.6 cm) 15.5" (39.4 cm) 15" (38.1 cm) 7" (17.8 cm) Materials and Methods  45  3.4.1.3 Process Feed, Storage tanks and Pumps Influent Feed AWWTP centrate was used as the struvite reactor influent in background study, as well as in combination 1. As mentioned in Section 3.2, centrate supernatant was stored in a 5500 L holding tank. For combination 2, influent for the struvite column was the anammox effluent stored in a 1325 L storage tank. For all cases, the influent was pumped with a 6-600 rpm MasterflexTM L/S peristaltic pump (pump head no.18) at a flow rate of 340 ml/min to the struvite reactor through a ½ inch (1.27 cm) tubing and ball valve. Magnesium Feed Magnesium feed was stored in a 208 L tank after preparing it from commercial grade magnesium chloride hexahydrate pellets (MgCl2.6H2O). To maintain a Mg/P molar ratio of 1.3 inside the reactor, this Mg feed was pumped to the injection port with a 1-100 rpm MasterflexTM L/S peristaltic pump, at a flow rate of 6 to 9 ml/min through ¼ inch (0.64 cm) tubing.  Caustic Feed pH is an important variable of the struvite crystallization process and needed to be monitored and maintained. Since pH in the reactor drops due to struvite formation, caustic (NaOH) addition is needed to maintain the set pH. Approximately 1.0 M caustic feed was prepared from commercial grade sodium hydroxide pellets and stored in a 120 L tank. pH monitoring and caustic pumping was controlled by a HANNA Instruments pH controller, connected to a Oakton pH probe placed at the bottom of the active zone in the Materials and Methods  46  struvite reactor. The pH probe and pH controller were regularly calibrated by standard buffer solutions of pH 4, pH 7 and pH 10.  Recycle Line The recycle line running from the bottom of the external clarifier to the struvite column injection port through ½ inch (1.27 cm) tubing was operated by a Moyno 500 series (Model no 33160) progressing cavity pump, with a ½ HP motor and a digital VFD (variable frequency drive) controller. 3.4.1.4 Process Operations The struvite reactor was seeded with 100 ml of 1.0 mm struvite pellets at the beginning of each run, to reduce the time requirement for nucleation. After the crystallization process started, any produced fine pellets would act as new seed (Fattah, 2004). It was important to start running the feed and recycle pumps before seeding, to keep the seed fluidized to prevent clogging of the injection port. Magnesium and caustic pumps were turned on right after the seeding. Influent, recycle and magnesium feed were continuous, whereas the intermittent caustic feed was controlled by the pH controller. After completion of each run, the struvite pellets were harvested and dried for further analysis. 3.4.2 Anammox Reactor Setup for Combination 1 3.4.2.1 Anammox Reactor Design An 11.5 L reactor was used for the continuous anammox process, equipped with a mechanical paddle stirrer to achieve complete mixing. The liquid level in the reactor was set to be 10.8 L and mixing was done at 20 rpm, to avoid sludge break up due to high shear forces at higher mixing speed. The reactor temperature was maintained      lly 33-Materials and Methods  47  34  ) with a 150 W submerged heater. Intermittent aeration was done with the help of a timer attached to the air pump, to maintain anoxic/anaerobic conditions (DO level less than 0.5 mg/L) to limit NOB activity. An Oakton Waterproof DO 300 Meter and galvanic probe were used for DO measurements. When the timer was ON, air would flow though a flow meter and then through the porous-stone, fine-bubble diffuser mounted at the bottom of the reactor. In this study, the DO level was maintained between 0.20-0.25 mg/L. Reactor pH was monitored and maintained (mostly pH 6.6-6.8) with the help of an Oakton pH probe and pH controller (Eutech Instrum n   αlph -pH 800). The anammox reactor was wrapped with heat reflecting air bubble insulation sheets, to maintain desired reactor temperature. 3.4.2.2 External Clarifier for Anammox Process Anammox reactor effluent overflowed to a 1.2 L clarifier, which would retain the anammox bacteria and this settled sludge was then recycled back to the reactor. The supernatant (clear effluent) went to the drain.     3.4.2.3 Process Feed, Storage Tanks and Pumps Influent Feed  In the background study, centrate was used as the anammox process influent, whereas for the experimental setup of combination 1, struvite effluent was the influent feed. In   mi   n  in l  n       w    on  oll    y  h  E    h In    m n   αlph -pH 800 pH controller. The pH set point in the pH controller was set as 6.6-6.8 and an Oakton pH probe placed inside the reactor was connected to the controller. The pH controller would initiate feed pumping slowly with a 1-100 rpm MasterflexTM L/S peristaltic pump (flow Materials and Methods  48  rate 3.5 ml/min), if the reactor pH went below 6.6. Influent feed pumping would stop when the pH level reached 6.8 in the reactor. The HRT of the reactor varied, due to variable feed consumption rate.  Recycle Line Settled sludge from the bottom of the external clarifier was recycled back to the reactor continuously at a flow rate of 3.5 ml/min. Another 1-100 rpm MasterflexTM L/S peristaltic pump was used for this recycle. Aeration Aeration was done by an air pump (Top Fin® Air 8000) attached to a Cole-Parmer valved acrylic flow meter (0.4-5 LPM). In the study, the air flow rate was maintained 1.0-1.4 LPM through a fine bubble air diffuser. Aeration of 30 min ON/20 min OFF was controlled with a timer connected to the air pump. A check valve was installed after the flow meter to prevent back flow of water from the reactor to the flow meter, during air OFF time.    3.4.2.4 Process Operations Start up and System Failure The anammox reactor started running on Nov 15, 2013. At start up, 4L of mature anammox sludge was added with 6.8 L of hot water in the reactor. This mature anammox sludge was borrowed from a 400 L UniBAR-Anammox reactor running at the Annacis Research Centre by Prongineer R&D Ltd. pH set point was maintained as 6.8-7.0 and the   mp        w   33-34    Aeration was done by air flow of 0.5 LPM at 30 min ON/15 Materials and Methods  49  min OFF. This reactor failed twice within a month due to NO2 building up. Reactor failure on Nov 29, 2013 was due to an accidental increase in air flow rate and the second failure on 13 Dec, 2013 was due to cold temperature  10  ) in the reactor as reactor heater failed due to the building cold temperatures during that entire week; hence, NOB outcompeted AOB. The reactor was restarted on 13 Dec 2013, with 4L fresh mature sludge, 1L existing sludge and 5.8 L hot water.  Sludge Enrichment and System Optimization In this phase, aeration rate and time was adjusted to maintain TSS and VSS value higher than 2000 mg/L and an HRT around 2-4 days. To facilitate the growth rate of AOB, air flow rate was increased (1.0 to 1.4 LPM) and the air timer was adjusted to 30 min ON/20 min OFF. At the same time, the pH set point was changed to 6.6-6.8. Batch Test on Anammox Process In order to determine the effect of struvite effluent feed on anammox process, batch test were conducted on the UniBAR-anammox reactor. Centrate and Struvite Effluent feed were added to the reactor in batch mode, instead of the continuous feed process. 30% feed (3.3 L) was added to the 70% of the reactor sludge (7.5 L) and after complete mixing, the initial pH was recorded to be in the range of 7.5-7.6. Using the same aeration rate and ON/OFF time as in continuous feed process, the pH reduction was monitored until it went down to pH 6.0. Samples were collected from the reactor at 0.5 h interval. Batch tests were conducted at operating temperatures of 34  C, 30  C and 25  C. the low temperature test at 20   was unsuccessful with centrate feed (tested twice) and hence, was not tested with struvite feed.  Materials and Methods  50  The continuous process flow diagram and experimental setup for combination 1 is shown in Figures 3.8 and 3.9. Materials and Methods  51   Figure 3.8: Process flow diagram of Pre-Anammox-Struvite process (combination 1) Materials and Methods  52   Figure 3.9: Pilot scale experimental setup for Pre-Anammox-Struvite process (combination 1) Anammox Reactor Struvite Reactor Struvite External Clarifier Anammox External Clarifier Anammox pH controller Struvite pH controller Caustic feed Mg feed Seed Hopper Fines Zone Active Zone Harvest Zone Materials and Methods  53  3.4.3 Anammox Reactor Setup for Combination 2 3.4.3.1 Anammox Reactor Design The total volume of the pilot-scale, continuous process anammox reactor was 575 US gallons (2176 L), with the liquid volume set to be 480 US gallons (1816.8 L). A mechanical paddle stirrer was installed to achieve complete mixing at 15 rpm to facilitate granule formation and avoid sludge break up due to high shear forces. An operating reactor temperature o  33-34   was maintained with a special heating system consisting of a two 3kW over the side immersion heaters (Omega PTH-302) being controlled by two CBC992-250 thermostat controllers.  The heater elements were made of 316SS (stainless steel) and would stick into the tank 26 inches (66 cm) from the top, with the hot portion being the last 16 inches (40.64 cm).  The liquid level in the tank was not allowed to drop below 10 inches (25.4 cm) of the top of the tank and a low level switch cut-out system was used. A level switch attached with the heater was connected to the heater control box to ensure immediate shutdown of the heater if, in any case, the liquid level in the reactor dropped below the safe level for a heater.                                                                    Figure 3.10: Heating system installed for pilot scale anammox reactor Hot section of heater element Ideal liquid level Materials and Methods  54  A timer was used to supply air intermittently through a flow meter and then a disk diffuser mounted at the bottom of the reactor. The DO level in the reactor was between 0.2-0.25 mg/L. pH probe and pH controller (Eutech Instruments pH 190 series) were used to monitor and maintain pH 6.6 to 6.8 in the reactor.  3.4.3.2 External Clarifier for Anammox Process An external clarifier, having a total volume of 30 US gallons (113.5 L) and a liquid level of 25 US gallons (94.5 L) was installed after the anammox reactor to store the effluent. Anammox bacteria that were washed out from the reactor with the effluent, settled in the clarifier and the bottom sludge was then recycled back to the reactor. As a result, clear effluent would overflow from the clarifier.     3.4.3.3 Process Feed, Storage Tanks and Pumps Influent Feed  Centrate from the 5500 L storage tank was pumped intermittently, as the influent feed for this pilot-scale, anammox reactor depended on reactor pH and pH set point of the pH controller. A pH probe placed inside the reactor was connected to the Eutech Instruments pH 190 series pH controller. Centrate feed pumping started through a 6-600 rpm MasterflexTM L/S peristaltic pump (flow rate 600 ml/min) whenever the reactor pH dropped below pH set point (6.6-6.8) of the pH controller; pumping stopped after reaching the desired pH level. The HRT of the reactor was calculated from the feed consumption rate.     Materials and Methods  55  Recycle Line A 6-600 rpm MasterflexTM L/S peristaltic pump, with no. 18 pump head, was used to continuously recycle back the settled sludge from the bottom of the external clarifier to the anammox reactor, at a flow rate of 400 ml/min.  Aeration An HIBLOW HP-80 air compressor was used to provide 35 LPM air flow through a Cole-Parmer valved acrylic flow meter (10-100 LPM) and a disk diffuser at the bottom. An aeration ON/OFF time was controlled by a timer connected to the air pump. Back flow of water was prevented with the help of a check valve installed in between the flow meter and diffuser.    3.4.3.4 Process Operation Inoculation and Start up On Feb 13, 2014, 200 US gallons (757 L) of anammox effluent (collected from a 400 L UniBAR-Anammox reactor running at Annacis research centre by Prongineer R&D Ltd) was added with 82 US gallons (310 L) of centrate and 150 US gallons (568 L) of hot water in the pilot scale reactor. Reactor TSS and VSS were found to be 320 mg/L and 280 mg/L respectively. pH set point of 6.6-6.8 and a temperature of 33-34   were maintained at all times. At start up, an air flow of 0.5 LPM at 10 min ON/4 h OFF was used, which was later on increased step wise from 0.5 LPM to 25 LPM, and aeration ON/OFF time was adjusted for different combinations to facilitate the growth of bacteria. In this phase, priority was given to increase both TSS and VSS, while slowly decreasing the reactor HRT. On March 21, 2014, TSS and VSS were measured to be 840 mg/L and Materials and Methods  56  520 mg/L, respectively, and the HRT decreased to 15 days at 25 LPM air flow (15 min ON/2 h OFF). Sludge Enrichment and System Optimization Keeping the pH set point same as 6.6-6.8  n    mp        o  33-34  , only  h       ion rate and time was adjusted until the TSS and VSS reached the desired level of about 2000 mg/L and HRT dropped below 7 days. Achieving a low HRT was important for the process combination 2 in order to provide sufficient influent to the struvite column in the post-anammox process.  Figure 3.11 shows anammox granule under microscope (20x)   Figure 3.11: Anammox bacteria under microscope; left image at start up and right image after sludge enrichment  Anammox granule retained on filter paper (WhatmanTM glass microfiber filter 934-AHTM) is shown in Figure 3.12. Materials and Methods  57    Figure 3.12: Mature anammox granule  The process flow design for combination 2 is shown in Figure 3.13, and the experimental setup for combination 2 is shown in Figure 3.14.    Materials and Methods  58   Figure 3.13: Process flow diagram of Post-Anammox-Struvite process (combination 2) Materials and Methods  59   Figure 3.14: Pilot scale experimental setup for Post-Anammox-Struvite process (combination 2) Anammox Reactor Anammox External  Clarifier Anammox Effluent Storage tank Centrate Tank Struvite Reactor Struvite External Clarifier Anammox  pH Controller Materials and Methods  60  3.5 Reactor Operating Conditions Struvite and anammox reactor operating conditions for both combinations are shown in Table 3.2. Table 3.2: Reactor operating conditions for process combinations UniBAR-Anammox Process Air Flow Rate (LPM) 1 to 1.4 (reactor volume 10.8 L) 35 (reactor volume 1816.8 L) Air pump Timer 30 min ON/20 min OFF (reactor volume 10.8 L) 40 min ON/20 min OFF(reactor volume 1816.8 L) Dissolved Oxygen (mg/L) 0.2-0.25 pH set point 6.6-6.8               C) 34     on in o   P o    ) 34  , 30  , 25    n  20        h T   ) Mixer (rpm) 20 (reactor volume 10.8 L) 15 (reactor volume 1816.8 L) Struvite Column pH set point of Struvite Column 7.67 (Pre and Post-Anammox Struvite Process) 8.30 (Post-Anammox Struvite Process) Recycle ratio 5 Feed flow rate (L/min) 340 Desired Supersaturation Ratio (SSR) 4 Upflow velocity (cm/min) 400  Materials and Methods  61  3.6 Monitoring and Maintenance Feed and recycle flow rates of the reactors were regularly measured with the help of a graduated cylinder and stop watch. Temperature, pH, and conductivity of the influent, effluent and reactor contents were monitored regularly. A digital thermometer (300 series stainless steel stems) was used for temperature measurement. pH monitoring was done with Oakton pH probe and meter. The pH meter was calibrated bi-weekly using a 3 point calibration with standard buffer solutions of pH 4, pH 7 and pH 10. Conductivity was measured with a probe connected to a conductivity meter (HANNA Instruments, Hi 9033). The liquid levels in all the tanks (influent and chemicals) were recorded regularly to calculate the feed consumptions. Monitoring the dissolved oxygen and nitrite concentration inside the anammox reactor were of utmost importance as the DO level of anammox process needed to be less than 0.5 mg/L and nitrite build up in the system would inhibit anammox process and deteriorate reactor performance. Routine nitrite test check was done by a colorimetric method using the API Nitrite test kit to ensure that nitrite concentrations were below 25 mg N/L (see Figure 3.15). Higher than this value would reduce ammonium removal activity (Kang, 2014).                               Figure 3.15: Nitrite test by colorimetric method Materials and Methods  62  The Oakton Waterproof DO 300 Meter for dissolved oxygen measurement was calibrated using a 2 point calibration, with a sodium sulfite solution and an oxygen saturated solution. The anammox reactor maintenance was undertaken on a monthly basis. Reactor walls, mixer blade, and aerator were cleaned by mechanical scrubbing, while the tubes were cleaned with hot water running.  A lot of maintenance work was needed for the struvite reactor and external clarifier, due to the struvite formation on the walls, tubes and injection port. Mechanical scrubbing, along with running hot water, were to be performed on a weekly basis for the whole struvite reactor setup, while the injection port needed to be cleaned every alternate day.  3.7 Sample Collection and Preservation For the continuous, pilot-scale study, grab samples of influent, reactor and effluent of both anammox and struvite process were collected almost every weekday (sometimes on weekends too). For the batch test of the anammox reactor (combination 1), grab samples were collected from the reactor every half an hour during each test run. Grab samples were also being collected from the magnesium and caustic tanks on a bi-weekly basis, to measure the concentrations. For pH and temperature, collected liquid samples were analyzed immediately but for all other analyses, samples were immediately preserved and stored in a 4°C refrigerator. Solid samples of produced struvite pellets were dried, weighted and stored in air tight plastic bags for further analysis. 3.8 Sample Analysis Liquid samples were analyzed for pH, alkalinity, total suspended solids (TSS), volatile suspended solids (VSS), ammonia-nitrogen (NH4-N), nitrite-nitrogen (NO2-N), nitrate-Materials and Methods  63  nitrogen (NO3-N), phosphate (PO4-P), and particle size distribution. Chemical and XRD analysis were also performed on the solid samples of produced struvite pellets to confirm characteristics. After completing grain size distribution of struvite pellets, solid samples were analyzed for ammonia-nitrogen (NH4-N), phosphate (PO4-P) and magnesium (Mg) concentrations along with XRD analysis. pH, alkalinity, TSS and VSS tests were performed at the Annacis Wastewater Research Centre Lab; all other analyses were conducted at the Environmental Engineering Laboratory of the Department of Civil Engineering, University of British Columbia.  3.9 Analytical Methods 3.9.1 pH  Immediate Analysis   Electrometric Method by Oakton pH meter and pH probe    Standard Methods 4500 H+  (APHA, 2005)  3.9.2 Alkalinity  Immediate Analysis   Titration Method by Mantech TitraSip SA  Standard Methods 2320 B (APHA, 2005) 3.9.3 Ammonia-Nitrogen (NH3-N)  Flow injection analysis on Lachat QuickChem 8000(calibration range 0-50 mg/L)  Standard Methods 4500-NH3 H (APHA, 2005)  Samples were filtered through a 0 45 μm ni  o  ll lo    il    , diluted, preserved with 1 drop of 5% H2SO4 to pH<2 and stored at 4°C, dark until analysis Materials and Methods  64  3.9.4 Nitrite-Nitrogen (NO2-N)  Colorimetric Method on Lachat QuickChem 8000 (calibration range 0-25 mg/L)  Standard Methods 4500-NO2- B  (APHA, 2005).   Samples were filtered through a 0 45 μm ni  o  ll lo    il    , diluted, preserved with 1 drop of Phenylmercuric Acetate Solution to pH<2 and stored at 4°C, until analysis 3.9.5 Nitrate-Nitrogen (NO3-N)  Cadmium Reduction Flow Injection Method on Lachat QuickChem 8000 (calibration range 0-25 mg/L)  Standard Methods 4500-NO3- I (APHA, 2005).   Samples were filtered through a 0 45 μm ni  o  ll lo    il    , diluted, preserved with 1 drop of Phenylmercuric Acetate Solution to pH<2 and stored at 4°C, until analysis 3.9.6 Ortho-Phosphate (PO4-P)  Flow Injection Analysis for Orthophosphate on Lachat QuickChem 8000 (calibration range 0-25 mg/L)  Standard Methods 4500 Ortho-P G (APHA, 2005).   Samples were filtered through a 0 45 μm ni  o  ll lo    il    , diluted, preserved with 1 drop of 5% H2SO4 Solution to pH<2 and stored at 4°C, until analysis 3.9.7 Magnesium (Mg)  Flame atomic absorption spectrophotometry analysis with Varian Inc. SpectrAA220® Fast Sequential Atomic Absorption Spectrophotometer (AAS). Materials and Methods  65   Air/Acetylene (C2H2) flame method, Standard Methods 3111 B (APHA, 2005).  1 ml of sample was diluted with 9 ml of 20g/L Lanthanum solution (prepared from reagent grade Hexahydrate lanthanum nitrate and distilled water) to prevent interference by ionic species in AAS  1 drop of concentrated HNO3 was added to the prepared 10 ml sample to prevent interference by soluble organics and vortex mixing was done prior to analysis.  7 point calibration curve of 0, 0.25, 0.5, 1.0, 2.5, 5.0 and 10.0 mg/L Mg were utilized. 3.9.8 Caustic (NaOH)  Acid Titration Method  Standard Methods (ASTM, 2009)  Samples collected from caustic tank were titrated with strong acid (HNO3) and end point was detected with phenolphthalein indicator.  Concentration of  base (NaOH) was calculated from the equation below, Cacid x Vacid = Cbase x Vbase Where, Cacid = Concentration of acid, M or N Vacid = Volume of acid used Cbase = Concentration of base, M or N Vbase = Volume of base used 3.9.9 Total Suspended Solids and Total Dissolved Solids (TSS and VSS)  Thoroughly mixed samples were filtered through pre-weighted WhatmanTM glass microfiber filter (934-AHTM)  n    i   ov  nigh     103-105   in VW    i n i i  Materials and Methods  66  1350 FM forced air oven (for TSS)  n   h n    550    o  1 h in Thermolyne 30400 furnace (for VSS)  Samples weighted on Ohaus Adventurer AR0640   Standard Methods 2540 D/E (APHA, 2005)   TSS and VSS were calculated as shown below, TSS, mg/L = (103/105     y w igh  - Filter weight), mg / volume of sample, L VSS, mg/     550    y w igh -103/105     y w igh ), mg / vol m  o    mpl ,   3.9.10 Particle Size Distribution   Light Scattering Method on Mastersizer 2000 with Hydro 2000S auto sampler  Standard Methods 2560 D (APHA, 2005)   Particle size distribution graphs were generated along with D10, D50, D90 values 3.9.11 Sieve Analysis of Struvite Pellets  Sieve analysis was performed on the air dried harvested struvite pellets  Standard ASTM C136/C136M (ASTM, 2014)  Standard sieves of No. 5 (4 mm), No. 10 (2 mm), No. 18 (1 mm), No. 35 (0.5 mm) and No. 120 (0.125 mm) of American Standard Sieve Series ASTM E-11 specification were used to separate the harvested pellets according to size.  Each size fraction was then weighted on Ohaus Adventurer AR0640. 3.9.12 Chemical Analysis of Struvite Pellets  Sample pellets were crushed into powder, dissolved in distilled water with concentrated HCl acid addition and then analyzed for Mg, NH4-N and PO4-P to Materials and Methods  67  check the molar ratio of Mg:NH4:PO4 with the desired value of 1.0 for pure struvite.  Standard Methods 3111 B,  4500-NH3 H and 4500 Ortho-P G(APHA, 2005)  3.9.13 XRD Analysis of Struvite Pellets  X-Ray Diffraction (XRD) analysis was performed on the powdered struvite pellets to match the intensity and positions of the peaks produced from the sample to the powder diffraction database file, PDF-2, provided by the International Center for Diffraction Data (to identify crystal structure in the solids).  Bruker D8 Advance X-ray diffractometer with   Kα    i  ion was used for the analysis located in the UBC Department of Chemistry.  3.10 Terminology 3.10.1 Removal Efficiency Z-removal efficiency (%) =(Zinfluent-Zeffluent)*100/ Zinfluent Zinfluent= Concentration of Z in influent sample, mg/L Zeffluent= Concentration of Z in effluent sample, mg/L 3.10.2 Hydraulic Retention Time (HRT) HRT, days or min = VR/ Q VR=Volume of reactor, L Q = Flow rate, L/d or ml/min   Materials and Methods  68  Also, Q=Vf/T  Vf=Volume of feed consumed, L  T= time, days or min 3.10.3 Recycle Ratio Recycle Ratio (RR) = QRec/Qinf QRec = Recycle flow rate, ml/min or L/d Qinf = Influent flow rate, ml/min or L/d 3.11 Statistical Analysis 95% confidence intervals were calculated and shown as error bars in the graphs. If the confidence intervals of any two values did not overlap, they were considered as statistically different.  Results and Discussion  69  4 Results and Discussion 4.1 Influent Characteristics (Centrate) AWWTP centrate was used as the process influent in this pilot-scale study. More than 500 L per day of centrate was fed to the reactors, over a period of 1 year. The fresh, onsite centrate characteristics varied during the study. A summary of the Annacis wastewater treatment plant centrate characteristics is presented in Table 4.1. Table 4.1: Annacis centrate characteristics (February to December 2014) Parameters Units n Average ± 95% CI Maximum Minimum Temperature  C 54 19.4 ± 0.7 26.3 15.0 pH   100 7.9 ± 0.02 8.2 7.7 Conductivity mS/cm 10 7.0 ± 0.5 8.0 6.8 Alkalinity (CaCO3) mg/L 100 3010.0 ± 99.4 3787.8 1731.0 Total Suspended Solids (TSS) mg/L 100 239.4 ± 10.6 420.0 120.0 Volatile Suspended Solids (VSS) mg/L 100 202.1 ± 8.9 350.0 110.0 Magnesium (Mg) mg/L 50 5.5 ± 0.38 12.4 2.0 Ammonia-Nitrogen (NH4-N) mg/L 100 722.9 ± 33.4 1041.8 368.7 Phosphate (PO4-P) mg/L 100 119.9 ± 4.1 168.6 67.6 Nitrite-Nitrogen (NO2-N) mg/L 52 0.6 ± 0.2 2.7 0.0 Nitrate-Nitrogen (NO3-N) mg/L 52 0.1 ± 0.05 0.9 0.0  This centrate was rich in ammonia, with an average NH4-N concentration of about 722.9±33.4 mg/L. Maximum NH4-N was found to be 1041.8 mg/L, while the lowest was recorded to be 368.7 mg/L. The average PO4-P concentration was 119.9±4.1 mg/L, with a maximum value of 168.6 mg/L and a minimum of 67.6 mg/L. The N: P molar ratio was calculated to be 13.4: 1.0, based on average values. Both NH4-N and PO4-P values reflected values from the literature review (Britton, 2002; Fattah, 2004; Hassan, 2013). The lowest values were recorded at the time of unintentional dilution of centrate by DAF Results and Discussion  70  subnatant. This incidence took place when there was not enough centrate supply and the DAF subnatant was used to flush the supply lines.  The pH of the centrate was 7.9 ±0.02 (High 8.2, low 7.69), which favoured the struvite precipitation process and minimized caustic requirement. Due to the low concentration of Mg in the centrate feed (average 5.5±0.38 mg/L), external Mg needed to be added to the UBC struvite crystallizer, as explained in Section 2.6.3.5 and Section 3.4.1.3. Conductivity was used (average of 7.0±0.5 mS/cm) as one of the input parameters in Potts model (Potts, 2002), to estimate the required pH set point of the pH controller in the struvite precipitation process, to maintain the desired SSR in the reactor (Fattah, 2004; Forrest, 2004). In the summer, the centrate   mp        w      high    26  , while in winter as low as 12  . Also, the centrate temperature was the same as room temperature in the research hall, since fresh centrate was stored for at least 2 days in a 5500 L storage tank for increased solids removal.  The NO2-N concentration was too low in the centrate, averaging 0.6±0.2 mg/L, reflecting similar results in another study conducted with WWTP centrate (Wu, 2012). Therefore, partial nitrification process was to be incorporated in the anammox process to ensure sufficient nitrite for the anammox process (as previously explained in Section 2.5.2). Average NO3-N concentration was also found to be very low, (0.14±0.1 mg/L). The average TSS in the centrate was 239.4±10.6 mg/L, while VSS was 202.10±8.96 mg/L. The alkalinity (as CaCO3) of the centrate was on an average 3010.1±99.4 mg/L, which was consumed in the UniBAR-anammox reactor.   Results and Discussion  71  4.2 Combination 1 (Pre-Anammox-Struvite Process) Results In combination 1, the centrate was fed to the struvite column and UniBAR-anammox reactor separately as the first step, and then the two processes were combined. For better understanding of the results and data, 4 sampling locations, along with their corresponding data series notation for the combined step, is shown in Figure 4.1.      4.2.1 Phosphorus and Nitrogen Removal in Combination 1 4.2.1.1 P-Removal in Combination 1 Influent (centrate) was fed into struvite column and Mg feed was added externally. Reactor pH set point in the pH controller was 7.67, which controlled the caustic addition  o m in  in  h     i    SS  o  4 0     im     wi h Po  ‘  mo  l)  PO4-P in the influent (centrate) fed into struvite column varied in the range of 67.6 mg/L to 147.8 mg/L and the effluent PO4-P range was 3.0 to 30.0 mg/L.  The PO4-P concentration in the influent and effluent of the struvite column itself is shown in Figure 4.2 Location (4) Final Effluent of Combined Process (=Anammox Effluent) Combination 1: Pre-Anammox-Struvite Process Location (1) Influent (Centrate)  Struvite Precipitation with UBC Reactor UniBAR Anammox Process Location (2) Anammox Influent (=Struvite Effluent) Location (3) Anammox Reactor  Figure 4.1: Sampling locations and notations for Combination 1 Results and Discussion  72   Figure 4.2: Phosphorus removal in Struvite process (Combination 1) An average P-removal efficiency of 90.8±1.8 % (maximum 97.5%, minimum 71.5%) and N-removal efficiency of 9.1±1.6 % (maximum 31.8%, minimum 0%) were achieved in the struvite precipitation process. A plot of percentage removal efficiencies for PO4-P and NH4-N removal is shown in Figure 4.3.  Figure 4.3: Percentage removal of P and N in Struvite process (Combination 1) 020406080100120140160PO4-P (mg/L) Phosphate Concentration in influent and effluent of Struvite Precipitation Process InfluentPO4-PEffluentPO4-P0.0020.0040.0060.0080.00100.00120.00(%) Removal Percentage PO4-P  and NH4-N  removal in Struvite Process % P-removal% N-removalResults and Discussion  73  4.2.1.2 N-Removal in Combination 1 In the previous background study, before combining the two processes, centrate was the influent for anammox, as well as the struvite reactor. Influent (centrate) NH4-N varied between 419.5 and 1061 mg/L, while effluent NH4-N concentration was 400.5 to 1030 mg/L. NH4-N concentration in the influent and effluent of struvite column is shown in Figure 4.4.    Figure 4.4: Ammonia removal in Struvite process (Combination 1) The struvite precipitation process removed less than 10% (average 9.1±1.6 %) of NH4-N from the centrate itself.  The subsequent anammox process was responsible for the larger portion of N-removal. The average NH4-N load, coming from the centrate to UniBAR-anammox reactor was 915.2±33.6 mg/L and after removal average NH4-N in the anammox effluent was found to be 217.0±8.0 mg/L. N-removal efficiency in the UniBAR-anammox process, with 30040050060070080090010001100NH4-N (mg/L) Ammonia Concentration in influent and effluent of Struvite Precipitation Process  Influent(Centrate)NH4-NEffluentNH4-NResults and Discussion  74  centrate feed, could reach as high as 79.8%, while the lowest as 72.3%. After that, the combination started where the influent (centrate) was fed into struvite reactor first (average NH4-N load 747.1±27.2 mg/L, maximum 1041 mg/L, minimum 596.9 mg/L) and the struvite effluent (average NH4-N load 678.71±27.2 mg/L) was used as the influent for anammox reactor. The anammox effluent was the final effluent of the combined process, where NH4-N fluctuated between 123.9 to 320.6 mg/L, with an average of 206.2±9.8 mg/L. Therefore, N-removal efficiency in the anammox process, with struvite effluent feed varied between 61% and 78.7%. With an additional N-removal of 1.0% to 24% by the struvite precipitation process itself, the combined N-removal efficiency achieved was as high as 95.5%, while the lowest was 67%. The concentration of NH4-N in influent and effluent of the background and combination step is shown in Figure 4.5.   Figure 4.5: Ammonia-Nitrogen concentration in Combination 1 0200400600800100012005-Feb-14 27-Mar-14 16-May-14 5-Jul-14 24-Aug-14NH4-N (mg/L) Ammonia-Nitrogen Concentration in Influent and Effluent (Struvite+Anammox) Combined Process  Influent for AnammoxProcess (StruviteEffluent)Final Effluent(Combined Process)Influent (Centrate toStruvite Reactor)Influent (Centrate toAnammox Reactor)Anammox EffluentResults and Discussion  75  The percentage N-removal efficiency in struvite precipitation, UniBAR-anammox and the combined process, are all shown in Figure 4.6.   Figure 4.6: N-removal efficiency in Combination 1 In the background study with centrate feed, the average N-removal efficiency of 76.2±1.0% was achieved with the UniBAR-anammox process. The process combination started on 07 April, 2014. After combining, the anammox process N-removal efficiency was, on average 70±1.1%. This reduction in N- removal efficiency was due to reactor failures, which occurred twice (13 Jun, 2014 and again on 28 Jun, 2014). The reason behind the reactor failures was the replacement of the air flow pump as the old one stopped working properly. While adjusting the air flow rate and aeration time with the new pump, an excess amount of air was introduced into the anammox reactor, unintentionally causing nitrite buildup and eventual reactor failure. The average N-removal efficiency in combination 1 is shown in Figure 4.7. 0.0010.0020.0030.0040.0050.0060.0070.0080.0090.0010-Feb-14 1-Apr-14 21-May-14 10-Jul-14 29-Aug-14% N-removal Percentage N-removal in (Struvite+Anammox) Combined Process  N-removal inAnammox Process(Struvite Effluentfeed)N-removal inStruvite Process(Centrate feed)N-removal inStruvite+AnammoxCombined ProcessN-removal inAnammox Process(Centrate Feed)Results and Discussion  76   Figure 4.7: Average N-removal in Combination 1 The bar charts in Figure 4.7 indicate that an average N-removal efficiency in the anammox process was 76.2±1.0% with centrate feed and 70±1.1% with struvite effluent feed. In the combination process, with an additional 9.1±1.6% N-removal by struvite precipitation process, average combined N-removal was achieved as 79.2 ± 1.9%. 4.2.2 Variation in Wastewater Characteristics Before and After Combination 1 TSS, VSS, NO2-N, NO3-N, alkalinity, pH and conductivity were measured in the influent, effluent and reactor samples. Results were plotted, as shown in Figures 4.8 to 4.16. TSS and VSS values were used to determine the sludge holding capacity. Also, the graphs helped in the understanding of the anammox reactor start up, sludge enrichment and system optimization phases. TSS and VSS variation in combination 1 are shown in Figure 4.8 and 4.9, respectively, where the influent data are quite similar for both centrate (before combination) and struvite effluent (after combination) values.  76.19 70.01 9.14 79.15 0.0010.0020.0030.0040.0050.0060.0070.0080.0090.00% N-removal Average N-removal (%), Error Bar Showing 95% CI N-removal in (Struvite+Anammox) Combined Process N-removal by AnammoxProcess (Centrate Feed)N-removal by AnammoxProcess (Struvite Effluent Feed)N-removal by Struvite ProcessN-removal by(Struvite+Anammox) CombinedProcessResults and Discussion  77   Figure 4.8: TSS variation in Combination 1   Figure 4.9: VSS variation in Combination 1 It can be seen that TSS in influent (centrate) varied between 140 to 310 mg/L, whereas 110 to 310 mg/L TSS was detected in the influent (struvite effluent). The VSS variation range (100 to 320 mg/L) was the same for both influents.   05001000150020002500300035004000450050001003005007009001100130015005-Feb-14 27-Mar-14 16-May-14 5-Jul-14 24-Aug-14Reactor and Effluent TSS (mg/L) Influent TSS (mg/L) TSS Variation in (Struvite+Anammox) Combined Process  Influent(StruviteEffluent)Influent(Centrate)AnammoxReactorAnammoxEffluent05001000150020002500300035004000450050001003005007009001100130015005-Feb-14 27-Mar-14 16-May-14 5-Jul-14 24-Aug-14Reactor and Effluent VSS(mg/L)   Influent VSS(mg/L) VSS Variation in (Struvite+Anammox) Combined Process  Influent(StruviteEffluent)Influent(Centrate)AnammoxReactorAnammoxEffluentResults and Discussion  78  The anammox reactor and effluent curves for TSS and VSS showed a similar pattern and range of data. At start up, the reactor TSS was 3680 mg/L and VSS was 2380 mg/L, which gradually increased to a maximum of 4080 mg/L TSS and 4640 mg/L VSS in the sludge enrichment phase. After that, aeration was adjusted in the system optimization phase to reduce the HRT of the reactor. In this phase, TSS and VSS started to decrease and reached a stable reactor condition around 2500 mg/L. When the combination started, TSS and VSS curves demonstrated slight ups and downs, until the reactor reached a steady condition - a TSS in the range of 2000-2500 mg/L, with VSS ranging from 1700-2000 mg/L. The final effluent of the combined process (same as anammox effluent) was in the range of 1000 to 1500 mg/L, in the steady-state condition. Reactor failure points showed a sharp drop in TSS and VSS values, indicating fewer bacteria in the reactor.  The change in NO3-N concentration in combination 1 is shown in Figure 4.10.     Figure 4.10: Nitrate-Nitrogen variation in Combination 1 0501001502002500123456789105-Feb-14 27-Mar-14 16-May-14 5-Jul-14 24-Aug-14Effluent and Reactor NO3-N (mg/L) Influent NO3-N (mg/L) Nitrate-Nitrogen Concentration in Anammox Process: (Struvite+Anammox) Combined Process  Influent (StruviteEffluent)Influent (Centrate)Anammox EffluentAnammox ReactorResults and Discussion  79  The influent (both centrate and struvite effluent) was low in NO3-N (average 0.2±0.1 in centrate and 0.4±0.1 in struvite effluent). Collected samples of anammox reactor and effluent showed similar pattern and results. At start up, the anammox reactor NO3-N was 102 mg/L, which slowly increased to a value of 146 mg/L during sludge enrichment and system optimization with increased aeration. Immediately after the combination started, there was a drop in the NO3-N concentration to 71 mg/L, possibly due to the change in feed. However, it started to recover the next day and slowly increased to 180 mg/L; from this point forward, the NO3-N level in the reactor varied between 100 and 190 mg/L. The NO2-N concentration in combination 1 is plotted in Figure 4.11.  Figure 4.11: Nitrite-Nitrogen variation in Combination 1 Data points, showing high levels of NO2-N corresponded to reactor failure conditions, which occurred twice (due to the high air flow from new pump). For a better 0204060801001205-Feb-14 27-Mar-14 16-May-14 5-Jul-14 24-Aug-14NO2-N (mg/L) Nitrite-Nitrogen Concentration in Anammox Process: (Struvite+Anammox) Combined Process  Influent (Struvite Effluent)Influent (Centrate)Anammox EffluentAnammox ReactorResults and Discussion  80  understanding of the results, these 3 data points are excluded in the next graph (Figure 4.12).   Figure 4.12: Nitrite-Nitrogen variation in Combination 1 removing reactor failure data points In Figure 4.12, most of the data points (influent, reactor and effluent) fell within the range of 0 to 0.5 mg/L NO2-N. The anammox reactor and effluent had some NO2-N values higher than 0.5 mg/L (as high as 2.5 mg/L).   Alkalinity and pH variations are shown in Figure 4.13 and 4.14. The average alkalinity (as CaCO3 equivalent) in the influent (centrate) was 3004.3±89.2 mg/L (1731 to 3777 mg/L) and the average pH was 8.1±2.1 (7.72 to 8.26).  Struvite effluent had a slightly lower alkalinity averaging 2427±140.7 mg/L (1452 to 3450 mg/L) and pH averaging 7.8±0.03 (7.7 to 8.2), compared to the centrate. The alkalinity of the anammox reactor and effluent were in the range of 121 to 290 mg/L and pH 6.3 to 6.4 (average 6.3±0.03). 00.511.522.5311-Jan-14 2-Mar-14 21-Apr-14 10-Jun-14 30-Jul-14 18-Sep-14NO2-N (mg/L) Nitrite-Nitrogen Concentration in Anammox Process except failure data points: (Struvite+Anammox) Combined Process  Influent (Struvite Effluent)Influent (Centrate)Anammox EffluentAnammox ReactorResults and Discussion  81  The drop in pH level in the anammox reactor and effluent from the influent was due to the alkalinity consumed in the anammox process.   Figure 4.13: Alkalinity variation in Combination 1  100200300400500600700800050010001500200025003000350040005-Feb-14 27-Mar-14 16-May-14 5-Jul-14 24-Aug-14Anammox Reactor and Effluent alkalinity (mg/L)   Influent alkalinity (mg/L) Alkalinity Variation in (Struvite+Anammox) Combined Process  Influent(StruviteEffluent)Influent(Centrate)AnammoxEffluentAnammoxReactorResults and Discussion  82   Figure 4.14: pH variation in Combination 1 Conductivity was measured in the collected samples from all 4 locations and is plotted in Figure 4.15. Average values are shown in Figure 4.16.  Figure 4.15: Conductivity measurements in Combination 1  66.577.588.595-Feb-14 27-Mar-14 16-May-14 5-Jul-14 24-Aug-14pH pH Variation in (Struvite+Anammox) Combined Process  Influent(StruviteEffluent)Influent(Centrate)AnammoxEffluentAnammoxReactor012345678931-Aug 2-Sep 4-Sep 6-Sep 8-Sep 10-Sep 12-SepConductivity (mS/cm)  Conductivity Variation in (Struvite+Anammox) Process Struvite Column Influent(Centrate)Anammox Process Influent(Struvite Column Effluent)Anammox reactorFinal Effluent (Combinedprocess)Results and Discussion  83   Figure 4.16: Average Conductivity values in Combination 1 Since conductivity is a direct measure of ions in a solution, conductivity might change depending upon the amendment procedure and reaction state, as struvite precipitates out of the solution (Shepherd et al., 2009). As mentioned in Section 4.1, influent conductivity was one of the input parameters in Potts model (Potts, 2002), for estimating the required pH set point in the struvite precipitation process, to maintain the desired SSR in the struvite reactor (Fattah, 2004; Forrest, 2004). For a certain percentage P-removal in struvite process, pH set point in the reactor needed to be increased, with the increase in influent conductivity level. The average conductivity in influent (7.1±0.5 mS/cm) and effluent (7.4±0.5 mS/cm) of the struvite precipitation process, fell within the 95% CI and, hence, were not statistically different.  Conductivity can also be used as a monitoring parameter for the anammox process. During partial nitrification and anammox processes, the ammonium and hydrogen carbonate ions are converted into gas molecules; hence, conductivity decreases with increase in nitrogen removal (Szatkowska et al., 2007). As a result, in combination 1, the average conductivity of anammox influent (same as struvite column effluent) of 7.4±0.5 7.01 7.40 2.46 2.53 0.002.004.006.008.0010.00Conductivity (mS/cm) Average Conductivity in the (Struvite +Anammox) Combined Process Struvite Column Influent(Centrate)Anammox process Influent(Struvite Column Effluent)Anammox ReactorFinal Effluent (CombinedProcess)Error bar 95% Confidence interval Average Results and Discussion  84  mS/cm, decreased to a value of 2.5±0.3 mS/cm in the anammox reactor, as nitrogen was removed in the anammox process. There was no significant change in the anammox reactor and effluent conductivity levels.  The particle size distribution graphs in combination 1 are shown in Figure 4.17 and the average particle size results are given in Table 4.2.  Figure 4.17: Particle size distribution Combination 1  Table 4.2: Average particle size in combination 1 Average Particle Size (µm) Influent (Centrate) Anammox Influent (=Struvite Effluent) Anammox Reactor Final Effluent of Combined Process (=Anammox Effluent) D10 3.9 14.5 40.8 30.0 D50 12.5 104.3 181.0 114.3 D90 75.6 375.9 683.7 285.6  Results and Discussion  85  From Figure 4.17 and Table 4.2, it can be seen that the influent (centrate) contained smaller size particles with average median particle size of 12.5 µm. Particle size fraction increased after the struvite process, due to the formation of struvite fines, which further increased in the anammox reactor samples (because of the anammox granules present). However, the particle size distribution of final effluent (same as anammox effluent) showed smaller fraction than the reactor samples, as the larger anammox granules were settled in the external clarifier and recycled back to the anammox reactor.     4.2.3 Effect of Struvite Effluent Feed on UniBAR-Anammox Process In order to observe the effects of change in feed (from centrate to struvite effluent) on the UniBAR-anammox process in the combined continuous process, average values of different wastewater parameters are presented in Figures 4.18 and 4.19.   Figure 4.18: Comparison of average pH and NO2-N values before and after Combination1  0.001.002.003.004.005.006.007.008.009.00Influent(Centrate)AnammoxReactorEffluent Influent(StruviteEffluent)AnammoxReactorEffluent Before combination After combinationpH and NO2 -N (mg/L) Average Values of pH and NO2-N in (Struvite+Anammox) Combined Process pHNO2-N (mg/L)Results and Discussion  86   Figure 4.19: Comparison of average NO3-N, Alkalinity, TSS and VSS values before and after Combination 1 Looking at the wastewater characteristics before and after the combination, similar results and patterns were observed. Since the influent characteristics remained similar in both feeds, the reactor and the effluent characteristics were expected to show similar results, as seen here. In addition, to get a clear understanding of the struvite effluent feed effect, the anammox behavior was closely observed before and after the combination (shown in Figures 4.20 to 4.22).   Figure 4.20: Anammox reactor behaviour (HRT, pH, NO2-N) before and after Combination 1 (Error bar showing 95%CI) 0.00500.001000.001500.002000.002500.003000.003500.00Influent(Centrate)AnammoxReactorEffluent Influent(StruviteEffluent)AnammoxReactorEffluent Before combination After combination(mg/L) Average Values of Different Parameters in (Struvite+Anammox) Combined Process NO3-N (mg/L)Alkalinity (mg/L)TSS (mg/L)VSS (mg/L)4.44 4.24 6.63 6.61 0.25 0.78 0.001.002.003.004.005.006.007.00Average Values of HRT, pH and NO2-N in Anammox Reactor HRT BeforeCombinationHRT AfterCombinationpH BeforeCombinationpH AfterCombinationNO2-N BeforeCombinationNO2-N AfterCombinationpH NO2-N  (mg/L) HRT(days) Results and Discussion  87   Figure 4.21: Anammox reactor behaviour (Alkalinity and NO3-N) before and after Combination 1 (Error bar showing 95%CI)   Figure 4.22: Anammox reactor behaviour (TSS and VSS) before and after Combination 1 (Error bar showing 95%CI) No significant changes in anammox reactor behavior were observed after the combination in the continuous process run. With a 95% CI, the HRT, pH, alkalinity, NO3-N and VSS average values were statistically insignificant before and after the combination. The NO2-N level, after the combination, was slightly higher; this was more likely due to the higher NO2-N concentration values that subsequently resulted from 121.50 144.09 213.92 182.97 0.0050.00100.00150.00200.00250.00mg/L Average Values of Alkalinity and NO3-N  in Anammox Reactor NO3-N BeforeCombinationNO3-N AfterCombinationAlkalinity BeforeCombinationAlkalinity AfterCombinationAlkalinity (mg/L) NO3-N (mg/L) 2860 2408.39 2020 2181.58 0500100015002000250030003500mg/L Change in TSS and VSS values in Anammox Reactor  Initial TSS  BeforeCombinationTSS AfterCombinationInitial VSS BeforeCombinationVSS AfterCombinationVSS (mg/L) TSS (mg/L) Results and Discussion  88  reactor failure conditions, as explained earlier. This also explains the reduction in the TSS average value, after the combination. 4.2.4 Effect of Struvite Effluent Feed and Temperature on UniBAR-Anammox Process Behavior (Batch Test Results) To confirm the findings from the continuous process run, batch tests were conducted on UniBAR-anammox reactor, where batch feed of centrate and struvite effluent were undertaken as described in Section 3.4.2.4. Di     n  op    ing   mp          34  , 30  , 25    n  20  C) were also employed, to observe the temperature effect. After the addition of the feed, the reactor was mixed completely and initial pH was recorded (7.5 to 7.7). Aeration rate and ON/OFF time was kept same as in continuous process and the samples were collected every half an hour, to determine the change in wastewater characteristics until the pH dropped to 6.0. The low temperature test at 20  C with centrate feed was unsuccessful. The reactor failed within 8h of startup, as NO2-N built up in the reactor and at a   mp          low 25  C, NOB outcompete AOB (Khin and Annachhatre, 2004).  Figure 4.23: Effect of Struvite effluent feed and temperature on Anammox reactor pH 66.577.580 10 20 30 40pH Time (h) Anammox Reactor pH Centrate Feed T-34 CCentrate Feed T-30 CCentrate Feed T-25 C Centrate Feed T-20 CStruvite Effluent Feed T-34 CStruvite Effluent Feed T-30 CStruvite Effluent Feed T-25 CResults and Discussion  89  It can be seen in Figure 4.23, that for 3 different temperatures, a decreasing pH pattern was similar and for a certain temperature, both feeds exhibited data points very close to each other. Also, higher temperatures demonstrated better performance and higher reaction rates which, similar to the finding of another batch feed study with centrate feed (Wu, 2012).  The highest operating temperature of 34   was the shortest cycle, which indicates that the favorable temperature range for anammox process is around 35-37  C (Schmidt et al., 2003; Strous et al., 1999). The time required for completing each cycle is given in Table 4.3, showing that time requirement increased with a decrease in temperature.  Table 4.3: Effect of struvite effluent feed and temperature on anammox process cycle time in batch test Operating Temperature Time to reach pH 6.0 Centrate Feed Struvite Effluent Feed 34  C 23.5 h 23 h 30  C 25.5 h 26 h 25  C 29 h 28.5 h 20  C Reactor Failed within 8h   The same results as pH were observed with alkalinity as shown in Figure 4.24.  Results and Discussion  90   Figure 4.24: Effect of Struvite effluent feed and temperature on Anammox reactor alkalinity The alkalinity consumption rate was higher with higher temperature; as alkalinity was consumed, the pH in the reactor decreased. At 20  C, alkalinity consumption was negligible. Dissolved oxygen in the reactor (when air flow was ON) increased with decreasing temperature; a sharp increase in DO level was observed at 20  C, as seen in Figure 4.25. This was an expected result.   Figure 4.25: Effect of Struvite effluent feed and temperature on Anammox reactor dissolved oxygen level 01002003004005006007008000 10 20 30 40Alkalinity (mg/L) Time (h) Anammox Reactor Alkalinity   Centrate Feed T-34 CCentrate Feed T-30 CCentrate Feed T-25 C Centrate Feed T-20 C Struvite Effluent Feed T-34 CStruvite Effluent Feed T-30 CStruvite Effluent Feed T-25 C0246810120 10 20 30 40DO (mg/L) Time (h) Anammox Reactor Dissolved Oxygen   Centrate Feed T-34 C Centrate Feed T-30 C Centrate Feed T-25 C Centrate Feed T-20 CStruvite Effluent Feed T-34 CStruvite Effluent Feed T-30 CStruvite Effluent Feed T-25 CResults and Discussion  91  NH4-N in the initial completely mixed reactor was around 250 mg/L, which gradually decreased and the last sample was taken at pH 6.0 (end of cycle). The NH4-N removal rate was highest at the highest temperature of 34  C, as expected (Figure 4.26). The lowest temperature of 20  C achieved only 20 mg/L reduction in 8 h, before failure.  Figure 4.26: Effect of Struvite effluent feed and temperature on Anammox reactor ammonia-nitrogen concentration The N-removal efficiency of the anammox batch system is presented in Table 4.4. The highest removal was around 70% at 34  , while only 56.4% to 57.5% removal was possible at 25  ; this indicated a lower N-removal rate (anammox activity inhibition) with decreasing temperature. Table 4.4: Effect of struvite effluent feed and temperature on anammox process N-removal in batch test Operating Temperature N-removal (%) Centrate Feed Struvite Effluent Feed 34   70.1% 70.4% 30   61% 60% 25   57.5% 56.4% 20   Reactor Failed  0.0050.00100.00150.00200.00250.00300.00350.000 10 20 30 40NH4-N (mg/L) Time (h) Anammox Reactor Ammonia-Nitrogen Centrate Feed T-34 C Centrate FeedT-30 C Centrate Feed T-25 CStruvite Effluent Feed T-34 CStruvite Effluent Feed T-30 CStruvite Effluent Feed T-25 C Centrate Feed T-20 CResults and Discussion  92   The NO2-N and NO3-N levels in the anammox reactor are plotted in Figures 4.27 and 4.28, respectively.  Figure 4.27: Effect of Struvite effluent feed and temperature on Anammox reactor nitrite-nitrogen Level   Figure 4.28: Effect of Struvite effluent feed and temperature on Anammox reactor nitrate-nitrogen level 0.000.501.001.502.002.503.003.504.004.500 10 20 30 40NO2-N (mg/L) Time (h) Anammox Reactor Nitrite-Nitrogen Centrate Feed T-34 C Centrate FeedT-30 C Centrate Feed T-25 CStruvite Effluent Feed T-34 CStruvite Effluent Feed T-30 CStruvite Effluent Feed T-25 C Centrate Feed T-20 C0.0020.0040.0060.0080.00100.00120.00140.00160.00180.000 10 20 30 40NO3-N (mg/L) Time (h) Anammox Reactor Nitrate-Nitrogen Centrate Feed T-34 C Centrate FeedT-30 C Centrate Feed T-25 CStruvite Effluent Feed T-34 CStruvite Effluent Feed T-30 CStruvite Effluent Feed T-25 C Centrate Feed T-20 CResults and Discussion  93  The NO2-N level in the reactor was quite stable in the range of 0.1 to 0.8 mg/L, except for some data points above 1 mg/L (which quickly decreased). These results indicated that the anammox bacteria utilized most of the nitrite produced by AOB in the partial ni  i i   ion p o      A   h  low   mp         on i ion o  20  C, NO2-N kept increasing, indicating inhibition of the anammox process at the lower temperature and the accumulation of nitrite, leading to reactor failure. The NO3-N concentration in the reactor showed an increasing trend with increasing time and decreasing temperature. The lowest temperature  25  C) had the highest NO3-N concentration in the reactor; at lower temperature, the anammox process was inhibited, while NOB became active and oxidized the excess NO2-N into NO3-N.  Overall,             o  p   o m n   w     hi v      high     mp          o   ll  h  p   m              A         in   mp       ,  imil     h vio   p     n  w    o    v    o   o h   n       n      vi      l  n         Th    o  ,  h  Uni A -anammox process was not affected by the struvite effluent feed.  4.3 Combination 2 (Post-Anammox-Struvite Process) Results In combination 2, for the first step, the centrate was fed to the struvite column and UniBAR-anammox reactor separately, as in combination 1. After that, two processes were combined. 4 sampling locations, along with their corresponding data series notation for combination 2, is shown below in Figure 4.29.   Results and Discussion  94         4.3.1 Phosphorus and Nitrogen Removal in Combination 2 4.3.1.1 P-Removal in Combination 2 In the background study with Influent (centrate), the pH set point used was 7.67. PO4-P in influent (centrate) varied in the range of 106 mg/L to 136 mg/L and the effluent PO4-P ranged between 3.0 to 30.0 mg/L. Therefore, P-removal efficiency was achieved as high as 97.5%, while the lowest was 77.5%. The N: P molar ratio in the influent (centrate) was 13.7, whereas in the combination process, when anammox effluent was fed to the struvite column, the N: P molar ratio was in the range of 3.5 to 5.6. The percentage removal efficiency with anammox effluent feed varied between 62.6 % and 82.5%, at the same pH set point of 7.67. In this second run, a lower removal efficiency was due to the lower N: P ratio; this required a higher pH set point in the reactor to maintain the desired SSR of 4.0. By not increasing the pH set point, the SSR was compromised, leading to a lower removal efficiency.  Location (4) Final Effluent of Combined Process (=Struvite Effluent) Combination 1: Pre-Anammox-Struvite Process Location (1) Influent (Centrate)  Struvite Precipitation with UBC Reactor UniBAR Anammox Process Location (3) Struvite Influent (=Anammox Effluent) Location (2) Anammox Reactor  Figure 4.29: Sampling locations and notations for Combination 2 Results and Discussion  95  In the third run, the pH set point was increased to 8.30 (estimated  y Po  ‘  mo  l)  o achieve an SSR of 4.0. As a result, removal efficiency increased to as high as 98.5%, with the lowest at 84%. The phosphorus removal efficiency is plotted in Figure 4.30.      Figure 4.30: Phosphorus removal in Struvite Process (Combination 2) A comparison of the average percentage P-removal efficiency is shown in Figure 4.31.   Figure 4.31: Average percentage P-removal in Struvite process (Combination 2) 0.0020.0040.0060.0080.00100.00120.000 5 10 15 20% removal Days of Operation Phosphorus Removal in Struvite Process Centrate Feed, pH set point7.67Anammox Effluent Feed, pH setpoint 7.67Anammox Effluent Feed, pH setpoint 8.3090.84 74.55 92.74 0.0020.0040.0060.0080.00100.00120.00% P-removal Average P-removal (%), with 95% CL P-removal by Struvite Process centrate feed, pH set point 7.67Anmx eff feed, pH set poiint7.67Anmx eff feed, pH set poiint 8.3Results and Discussion  96  At a pH set point of 7.67, the average P-removal was 90.8±2.8% with centrate feed; this decreased after the combination with anammox effluent feed (74.6±2.5%), due to the lower N: P molar ratio in the anammox effluent feed. To achieve over 90% removal, pH set point in the reactor was increased to 8.30, to maintain the desired SSR. Average P-removal again reached over 90% (92.7±3.8%). With a 95% CI, there was no difference in average P-removal before and after combination, at a pH set point of 7.67 and 8.30, respectively.  4.3.1.2 N-Removal in Combination 2  N-removal was achieved primarily by the anammox process, with a smaller portion of N-removal by the struvite precipitation process. NH4-N load coming from the centrate to UniBAR-anammox reactor varied between 459.6 and 934.3 mg/L and, after removal the average NH4-N in the anammox effluent was found to be in the range of 136.4 to 376.8 mg/L. The N-removal efficiency in the UniBAR-anammox process, with centrate feed, reached as high as 84.9%, while the lowest was 37.1%. The NH4-N concentration in combination 2, is shown in Figure 4.32.    Figure 4.32: Ammonia-Nitrogen concentration in Combination 2 0200400600800100030-Jul-14 19-Aug-14 8-Sep-14 28-Sep-14 18-Oct-14NH4-N (mg/L) Ammonia-Nitrogen Concentration in Influent and Effluent (Anammox + Struvite) Combined Process Influent (Centrate)Anammox Effluent (=StruviteInfluent)Final Effluent of CombinedProcess (=Struvite Effluent)Results and Discussion  97  When the two processes were combined, centrate was the influent feed into the UniBAR-anammox reactor and the anammox effluent (average NH4-N load 272.4±30.4 mg/L) was used as the influent for the struvite column. The struvite effluent was the final effluent of the combined process, with an average NH4-N of 241.9±24.9 mg/L (145.1 to 370 mg/L). Therefore, the struvite precipitation process removed an average 10.9±2.9% of NH4-N from the anammox effluent. With this additional N-removal, the combined N-removal efficiency reached 90.7%, with the lowest removal at 46.1%.  The average N-removal efficiency in combination 2 is shown in Figure 4.33.  Figure 4.33: Average N-removal efficiency in Combination 2 From these bar charts, it is seen that the average N-removal efficiency in the anammox process was 60.1±6.2% with centrate feed. In the combination process, with an additional 10.9±2.9% N-removal by the struvite precipitation process, average combined N-removal was 71.0±5.2%. The average N-removal efficiency in the anammox process, around 60%, was lower than expected. In order to identify the possible reason behind the lower than expected removal efficiency, the behavior of the pilot-scale UniBAR-anammox process in combination 2 is described in the next section. 60.14 10.86 71.00 0.0010.0020.0030.0040.0050.0060.0070.0080.0090.00% N-removal Average N-removal (%), Error Bar Showing 95% CI N-removal Efficiency in (Anammox + Struvite) Combined Process N-removal by AnammoxProcess (Centrate Feed)N-removal by Struvite ProcessN-removal by(Struvite+Anammox)Combined ProcessResults and Discussion  98  4.3.2 UniBAR-Anammox Process Results TSS and VSS values are plotted in Figures 4.34 and 4.35, showing the changes in startup, sludge enrichment and system optimization phases, along with the sludge holding capacity.   Figure 4.34: TSS variation within pilot scale Anammox reactor (Combination 2)   Figure 4.35: VSS variation within pilot scale Anammox reactor (Combination 2) 050010001500200025003000350040004500500010-Feb-14 1-Apr-14 21-May-14 10-Jul-14 29-Aug-14 18-Oct-14TSS (mg/L) TSS Variation within Pilot Scale Anammox reactor Start up Sludge Enrichment System Otimization Optimized  Condition 05001000150020002500300035004000450010-Feb-14 1-Apr-14 21-May-14 10-Jul-14 29-Aug-14 18-Oct-14VSS (mg/L) VSS Variation within Pilot scale Anammox reactor Start up Sludge Enrich ment System Optimization Optimized Condition Results and Discussion  99   Figure 4.36: VSS/TSS ratio within pilot scale Anammox reactor (Combination 2) TSS and VSS graphs in Figures 4.34 and 4.35 showed a similar pattern. At start up, reactor TSS was 320 mg/L and VSS was 280 mg/L (HRT 30 days), which gradually increased to 840 mg/L TSS and 520 mg/L VSS. VSS/TSS ratio was in the range of 0.65 to 0.7, during start-up phase (as seen in Figure 4.36). After one month, the HRT was reduced to 15days (as seen in Figure 4.37). In the sludge enrichment phase, TSS and VSS kept increasing and reached the desired level around 2000 mg/L. Also, the ratio of VSS/TSS increased from a value of 0.65 to 0.95, indicating biomass growth. After that, the aeration was adjusted in the system optimization phase to reduce the HRT of the reactor (5 to 7 days).  Due to the change in aeration, TSS and VSS decreased (same as VSS/TSS ratio) at first but increased as the bacteria became acclimatized. In the optimized system, VSS/TSS ratio remained steady in the range of 0.79 to 0.99. The N-removal efficiency (as seen in Figure 4.37) was in the range of 70 to 86% in the sludge enrichment phase, which decreased initially in the system optimization phase, but recovered with time. The reactor reached stable conditions and the removal efficiency 0.000.200.400.600.801.001.2010-Feb-14 1-Apr-14 21-May-14 10-Jul-14 29-Aug-14 18-Oct-14VSS/TSS VSS/TSS Variation within Pilot Scale Anammox reactor Start up Sludge Enrichment System optimization Optimized Condition Results and Discussion  100  increased again, from an average removal of 70% to a maximum 84% removal. Subsequently, there was a drop in removal efficiency for almost one month (lowest was 40%) and then it climbed up slowly to 70%. In order to explain this drop in N-removal efficiency, reactor HRT and NH4-N levels in the anammox process are plotted in Figures 4.37 and 4.38, respectively.   Figure 4.37: N-removal efficiency and HRT in pilot scale Anammox reactor The plot of HRT and percentage N-removal in the same graph showed that higher N-removal was associated with a higher HRT until the system was optimized. After that, HRT remained in the range of 5 to 7 days, but still the N-removal efficiency was inconsistent. Therefore, NH4-N levels in the influent and effluent of the UniBAR-anammox reactor was plotted (Figure 4.38) to explain this phenomenon in the optimized condition.  0510152025303540455001020304050607080901002-Mar-14 21-Apr-14 10-Jun-14 30-Jul-14 18-Sep-14 7-Nov-14HRT (Days) %N-removal Percentage N-removal and HRT in Pilot scale Anammox reactor % N-removalHRTStart up , Sludge Enrichment and System Optimization Optimized Condition Results and Discussion  101   Figure 4.38: Ammonia-Nitrogen concentration in pilot scale Anammox reactor (Combination 2) The effluent NH4-N concentration was in the range of 136 mg/L to 250 mg/L from mid-July to mid-September; however, the influent NH4-N concentration was quite low from mid-July to the end of August, due to the dilution of centrate, resulting in the low removal efficiency (%) values in Figure 4.37. As the influent NH4-N concentration increased, so did the removal efficiency and vice versa (see supporting data in Figure 4.35 showing increase in VSS). The NO2-N and NO3-N concentration within the anammox reactor were also plotted (as seen in Figures 4.39 and 4.40, respectively. 0100200300400500600700800900100020-Jul-14 9-Aug-14 29-Aug-14 18-Sep-14 8-Oct-14 28-Oct-14NH4-N (mg/L) Ammonia-Nitrogen Concentration in Pilot scale Anammox reactor (Optimized condition) Influent NH4Effluent NH4Results and Discussion  102   Figure 4.39: Nitrite-Nitrogen concentration within pilot scale Anammox reactor (Combination 2)   Figure 4.40: Nitrate-Nitrogen concentration within pilot scale Anammox reactor (Combination 2) At start up, the anammox reactor NO2-N was high, gradually decreasing to below 1.0 mg/L (ranging from 0 to 0.8 mg/L); this indicated mature anammox activity utilizing the NO2-N to produce N2 gas. In contrast, the NO3-N level in the reactor showed an increasing trend to a peak level of 270 mg/L, due to the increased aeration. After the 00.511.522.533.510-Feb-14 1-Apr-14 21-May-14 10-Jul-14 29-Aug-14 18-Oct-14NO2-N (mg/L) Nitrite-Nitrogen Concentration within Pilot scale Anammox Reactor 05010015020025030035010-Feb-14 1-Apr-14 21-May-14 10-Jul-14 29-Aug-14 18-Oct-14NO3-N (mg/L) Nitrate-Nitrogen Concentration within Pilot scale Anammox Reactor Results and Discussion  103  system was optimized, NO3-N decreased, possibly due to the utilization of NO2-N that was produced in the partial nitrification process. However, NO3-N increased as the influent (centrate) characteristics changed, because of the unintentional dilution.  4.3.3 Variation in Wastewater Characteristics Before and After Combination 2 TSS, VSS, NO2-N, NO3-N, alkalinity, pH and conductivity and particle size were all measured in the influent, effluent and reactor samples. The results are plotted in Figures 4.41 to 4.49. TSS and VSS variation in combination 2 are shown in Figures 4.41 and 4.42, respectively, where the values of all 4 data series are shown to be quite similar.  Figure 4.41: TSS variation in Combination 2 It can be seen that TSS in influent (centrate) was in the range of 120 to 360 mg/L, whereas 90 to 390 mg/L TSS was present in the struvite influent (anammox effluent). VSS variation ranged from 150 to 340 mg/L in influent (centrate) and 80 to 250 mg/L in struvite influent (anammox effluent). 05001000150020002500050010001500200025003000350040004500500030-Jul-14 19-Aug-14 8-Sep-14 28-Sep-14 18-Oct-14Influent and Effluent TSS (mg/L) Reactor TSS (mg/L) TSS Variation in (Anammox+Struvite) Combined Process Anammox ReactorInfluent (Centrate)Anammox Effluent(=Struvite Influent)Final Effluent ofCombined Process(=Struvite Effluent)Results and Discussion  104   Figure 4.42: VSS variation in Combination 2 The anammox reactor values for TSS and VSS showed similar patterns and ranges (2000 mg/L to 4500 mg/L). The final effluent of the combined process (same as struvite effluent) was in the range of 70 to 390 mg/L TSS and 70 to 190 mg/L VSS. In the influent (centrate) and anammox reactor, the VSS/TSS ratios were in the range of 0.77 to 1.07. The struvite influent (same as anammox effluent) and the final effluent had a lower VSS/TSS ratio ranging from 0.31 to 0.99 due to the biomass retention in the clarifier.  The change in NO2-N levels in combination 2 is shown in Figure 4.43.  0500100015002000250005001000150020002500300035004000450030-Jul-14 19-Aug-14 8-Sep-14 28-Sep-14 18-Oct-14Influent and Effluent VSS (mg/L) Reactor VSS (mg/L) VSS Variation in (Anammox+Struvite) Combined Process Anammox ReactorInfluent (Centrate)Anammox Effluent(=Struvite influent)Final Effluent ofCombined Process(=Struvite Effluent)Results and Discussion  105   Figure 4.43: Nitrite-Nitrogen concentration in Combination 2 The NO2-N values in combination 2, ranged between 0 to 3.0 mg/L. The anammox reactor and effluent samples showed slightly higher NO2-N level (0 to 2.4 mg/L) than the influent (0 to 2.0 mg/L). But, the change in average NO2-N level in the influent (1.1±0.3 mg/L) and the effluent (1.3±0.3 mg/L) of the struvite process was statistically insignificant.        The NO3-N concentration is plotted in Figure 4.44. Influent centrate was low in NO3-N (average 0.13±0.04). Collected samples of anammox reactor and effluent showed a similar increasing trend and values (ranging 80 to 300 mg/L). After the combination started, the anammox effluent was used as the influent for the struvite column and the final effluent of combined process (same as struvite effluent) resulted in NO3-N levels between 120 to 315 mg/L. Influent and effluent NO3-N concentrations in the struvite process had negligible variation, indicating that the struvite process was not affected by the high NO3-N level in the influent after combination, as opposed to the low NO3-N level in the influent (centrate) during the background study. 00.511.522.533.530-Jul-14 19-Aug-14 8-Sep-14 28-Sep-14 18-Oct-14NO2-N (mg/L) Nitrite-Nitrogen Concentration (Anammox+Struvite) Combined Process Influent (Centrate)Anammox ReactorAnammox Effluent(=Struvite Influent)Final Effluent ofCombined Process(=Struvite Effluent)Results and Discussion  106   Figure 4.44: Nitrate-Nitrogen concentration in Combination 2 pH and alkalinity variations in combination 2 are shown in Figures 4.45 and 4.46, respectively.   Figure 4.45: pH variation in Combination 2  00.511.522.505010015020025030035030-Jul-14 19-Aug-14 8-Sep-14 28-Sep-14 18-Oct-14Influent (Centrate) NO2-N (mg/L)) Reactor and Effluent NO3-N (mg/L) Nitrate-Nitrogen Concentration in (Anammox+Struvite) Combined Process Anammox ReactorAnammox Effluent(=Struvite influent)Final Effluent ofCombined Process(=Struvite Effluent)Influent (Centrate)5.566.577.588.5930-Jul-14 19-Aug-14 8-Sep-14 28-Sep-14 18-Oct-14pH pH variation in Influent and Effluent (Anammox+Struvite) Combined Process Influent (Centrate)Anammox ReactorAnammox Effluent (=StruviteInfluent)Final Effluent of CombinedProcess (=Struvite Effluent)Results and Discussion  107   Figure 4.46: Alkalinity variation in Combination 2 The average alkalinity (as CaCO3) in the influent (centrate) was 3052.9±86.7 mg/L (2477.1 to 3411.6 mg/L) and the average pH was 7.9±0.03 (7.77 to 8.1).  The alkalinity of the anammox reactor and effluent were in the range of 130 to 250 mg/L, at an average pH of 6.5±0.1. As alkalinity was consumed in the anammox process, the pH level dropped in the anammox reactor and effluent, as expected. After the combination, the anammox effluent was fed to the struvite column as influent, with an average pH of 6.5±0.1 and alkalinity of 170.9±7.8 mg/L. In the struvite effluent (same as final effluent for combined process), the pH was in the range of 7.0 to 7.5, as the pH set point of the struvite process was 7.67. At the beginning of October (struvite column run 3), the pH level was in the range of 8.0 to 8.3, as the pH set point was increased to 8.3 (due to the low N: P molar ratio in the struvite influent (anammox effluent)). In combination 2, the final effluent alkalinity ranged between 125 to 211 mg/L.  0501001502002503003504004505000500100015002000250030003500400030-Jul-14 19-Aug-14 8-Sep-14 28-Sep-14 18-Oct-14Reactor and Effluent Alkalinity (mg/L) Influent Alkalinity (mg/L) Alkalinity Variation in (Anammox+Struvite) Combined Process Influent (Centrate)Anammox ReactorAnammox Effluent(=Struvite influent)Final Effluent ofCombine Process(=Struvite Effluent)Results and Discussion  108  Conductivity measurement results are presented in Figure 4.47 and average values are presented using bar charts (Figure 4.48).  Figure 4.47: Conductivity variation in Combination 2   Figure 4.48: Average Conductivity in Combination 2 The average conductivity in influent (centrate) was 7.03±0.5 mS/cm; this was reduced in the anammox process with N-removal (as explained in Section 4.2.2). The anammox 012345678919-Aug 29-Aug 08-Sep 18-Sep 28-Sep 08-Oct 18-OctConductivity (mS/cm)  Conductivity Variation in (Anammox+Struvite) Combined Process Influent (Centrate)Anammox reactorAnammox EffluentStruvite column Influent(Anammox Effluent)Final Effluent (Combinedprocess)7.03 2.59 2.57 2.82 3.58 0.001.002.003.004.005.006.007.008.00Conductivity (mS/cm) Average Conductivity in (Anammox+Struvite) Combined Process Influent (Centrate)Anammox ReactorAnammox EffluentStruvite Column Influent(Anammox Effluent)Final Effluent (CombinedProcess)Error bar 95% CL Average Results and Discussion  109  reactor and effluent conductivity were the same (average 2.5±0.4 mS/cm). In the combined step, anammox effluent was used as the struvite column influent, showing an average conductivity of 2.8±0.3 mS/cm. In combination 1, influent conductivity input in Potts model (Potts, 2002) was 7.01±0.5 mS/cm (Section 4.2.2), whereas a lower value of influent conductivity (2.8±0.3 mS/cm) for combination 2, encouraged slightly higher pH set point in the struvite process to achieve equal percentage of P-removal in both combinations. In combination 2 (as seen in Figure 4.48), with 95% CI, anammox reactor, effluent and struvite influent had similar conductivity, while the final effluent (same as struvite effluent) had slightly higher conductivity (3.6±0.4 mS/cm), possibly due to the higher ionic concentration from chemical addition in the struvite process. Particle size distribution curves are shown in Figure 4.49 and the average particle size values are given in Table 4.5.  Figure 4.49:  Particle size distribution in Combination 2  Results and Discussion  110  Table 4.5: Average particle size in combination 2 Average Particle Size (µm) Influent (Centrate) Anammox Reactor Anammox Effluent Struvite Column Influent (=Anammox Effluent) Final Effluent of Combined Process (=Struvite Effluent) D10 3.5 42.2 32.7 31.8 7.1 D50 11.4 150.2 118.2 112.3 34.5 D90 82.2 625.9 284.9 275.1 175.2  As discussed in Section 4.2.2, for combination 1, the influent (centrate) particle size distribution curve in combination 2, also demonstrated smaller size fractions (Figure 4.49). The average median particle sizes for influent (centrate), anammox reactor, anammox effluent, struvite influent and struvite effluent (or final effluent) were found to be 11.4 µm, 150.2 µm, 118.2 µm, 112.3 µm and 34.5 µm, respectively.  The particle size increased in the anammox reactor samples due to the growth of anammox granules, which decreased gradually in the anammox effluent and struvite influent, because of the particles settling in the external clarifier and effluent storage tank. Larger particles were also retained in the struvite column and struvite external clarifier, resulting in smaller size fraction in the final effluent.     Results and Discussion  111  4.3.4 Effect of Anammox Effluent Feed on Struvite Precipitation Process and Caustic Consumption In combination 2, the main focus was on the struvite precipitation process, before and after combination. P-removal efficiency of the struvite precipitation process showed that over 90% removal was achievable with both feeds, but with an increase in pH set point for Post-Anammox-Struvite process (as already explained in Section 4.3.1.1).  Also, higher NO3-N level in the influent (in case of anammox effluent) had no effect on the struvite precipitation process, as shown in Figure 4.44. Therefore, a change in feed after combination 2, did not affect the struvite column performance. However, the chemical costs due to high caustic consumption, need to be considered (as seen in Figures 4.50 and 4.51).  Figure 4.50: Caustic consumption in Struvite precipitation process (Combination 1 and Combination 2) 00.511.522.533.5gm NaOH/gm P-removed Average Caustic Consumption  Caustic Consumption in Struvite Process in Both Combinations pH Set point 7.67; Pre-AnammoxpH Set point 7.67, N:P=4.75; Post-AnammoxpH Set point 8.3, N:P = 4.75; Post-AnammoxpH Set point 8.3, N:P = 3.67; Post-AnammoxpH Set point 8.3, N:P = 2.51; Post-AnammoxPre-Anammox pH 7.67 Post-Anammox pH 7.67 Results and Discussion  112    Figure 4.51: Average caustic consumption in Struvite precipitation process in Combination 1 and 2) In the pre-anammox-struvite process (combination 1) with centrate feed, caustic consumption was negligible, as the average influent pH (8.1±2.1) was higher than the pH set point of 7.67.  In contrast, in the post-anammox-struvite process (combination 2), the average influent pH of 6.5±0.1 was below the set point in the pH controller (pH 7.67), introducing caustic consumption. The average caustic consumption was 1.8±0.2 gm NaOH per gm P-removed, at a pH set point of 7.67. However, the P-removal efficiency was reduced due to the low N: P molar ratio, causing a lower SSR.  When the pH set point was increased to 8.30 in the third run, to achieve over 90% P-removal, caustic consumption also increased (as expected). It was also found that, at a certain pH, caustic consumption increased with the decrease in N: P ratio. Similar findings of higher caustic consumption from anammox effluent feed was discussed in the bench scale study by (Hassan et al., 2013).    1.83 2.23 2.60 3.34 00.511.522.533.54gm NaOH/gm P-removed Average Caustic Consumption  Caustic Consumption in Struvite Process with 95% CI pH Set point 7.67; Pre-AnammoxpH Set point 7.67, N:P=4.75;Post-AnammoxpH Set point 8.3, N:P = 4.75;Post-AnammoxpH Set point 8.3, N:P = 3.67;Post-AnammoxpH Set point 8.3, N:P = 2.51;Post-AnammoxPre-Anammox pH 7.67 Post-Anammox pH 7.67 Post Anammox, pH 8.3, Decreasing N: P Results and Discussion  113  4.4 Struvite Pellets Analysis in Combination 1 and 2  Successful nutrient recovery as struvite pellets were achieved in both combinations (see Figure 4.52).     Figure 4.52: Harvested Struvite pellets Struvite pellets of different sizes (4 mm, 2 mm, 1 mm, 0.5 mm, 0.125 mm) were recovered as seen in the sieve analysis results presented in Table 4.6. Table 4.6: Sieve analysis results of struvite pellets Sieve Size (mm) Pre-Anammox Struvite Pellets (Centrate Feed) Post-Anammox Struvite Pellets (Anammox Effluent Feed) Retained (g) %retained Retained (g) %retained 4 87.60 8.24 103.84 8.81 2 867.81 81.59 953.40 80.87 1 102.45 9.63 114.08 9.68 0.5 3.56 0.33 4.90 0.42 0.125 2.25 0.21 2.71 0.23 Total 1063.67 100.00 1178.92 100.00  Struvite pellets size distribution curves are plotted for both combinations in Figure 4.53. Results and Discussion  114   Figure 4.53: Struvite pellets size distribution graph Curves for both combinations overlapped, indicating that struvite pellet size fractions were same. The most frequent and recoverable size pellets were about 2 mm in diameter; a commercially attractive size for resale.  Further physical, chemical and XRD analysis were performed on the recovered pellets, to determine any possible change in struvite pellets recovered from Pre and Post Anammox Struvite Processes. Struvite pellets were also observed under the microscope, as shown in Figures 4.54 to 4.57. 01020304050607080900.1 1 10% mass (g/g) Particle Size (mm) Struvite Pellets Size Distribution Pre-Anammox StruvitePellets (Centrate Feed)Post-Anammox StruvitePellets (Anammox EffluentFeed)Results and Discussion  115   Figure 4.54: Pre-Anammox-Struvite pellets under microscope (10X)   Figure 4.55: Post-Anammox- Struvite pellets under microscope (10X) Larger pellets seemed to have more crevices than smaller pellets. Similar findings were discussed in another pilot scale study (Fattah, 2004).  Results and Discussion  116   Figure 4.56: Pre-Anammox-Struvite crystal under microscope, 300X magnification (Centrate Feed)      Figure 4.57: Post-Anammox Struvite crystal under microscope, 300X magnification (Anammox Effluent Feed) Rectangular prismatic-shaped struvite crystals were observed in both cases, as opposed to the elongated prismatic crystals for anammox effluent feed only mentioned earlier by (Hassan, 2013). XRD analysis results for the 2 mm pellets recovered from both combinations are shown in Figures 4.58 and 4.59 (XRD analysis results for all pellet sizes are given in Appendix B). Results and Discussion  117   Figure 4.58: XRD analysis of Pre-Anammox-Struvite pellets (2mm size)   Figure 4.59: XRD analysis of Post-Anammox-Struvite pellets (2mm size) 2 mm struvite00-015-0762 (*) - Struvite, syn - NH4MgPO4·6H2O - Y: 36.76 % - d x by: 1. - WL: 1.5406 - Orthorhombic - a 6.94500 - b 11.20800 - c 6.13550 - alpha 90.000 - beta 90.000 - gamma 90.000 - Primitive - Operations: ImportFile: Sifat2.raw - Start: 5.000 ° - End: 75.079 ° - Step: 0.010 ° - Step time: 36.4 s - Anode: Cu - WL1: 1.5406 - WL2: 1.54439 - kA2 Ratio: 0.5 - Generator kV: 40 kV - Generator mA: 40 mALin (Counts)0100020003000400050006000700080009000100001100012000130001400015000160001700018000190002000021000220002300024000250002600027000280002900030000310002-Theta - Scale5 10 20 30 40 50 60 70Anammox to struvite 2 mm00-015-0762 (*) - Struvite, syn - NH4MgPO4·6H2O - Y: 84.63 % - d x by: 1. - WL: 1.5406 - Orthorhombic - a 6.94500 - b 11.20800 - c 6.13550 - alpha 90.000 - beta 90.000 - gamma 90.000 - Primitive - Operations: ImportFile: A-S_200.raw - Start: 5.000 ° - End: 64.994 ° - Step: 0.019 ° - Step time: 36.4 s - Anode: Cu - WL1: 1.5406 - WL2: 1.54439 - kA2 Ratio: 0.5 - Generator kV: 40 kV - Generator mA: 40 mALin (Counts)01000200030004000500060007000800090001000011000120001300014000150006718000190002000021000220002300024000250002600027000280002-Theta - Scale6 10 20 30 40 50 60Results and Discussion  118  Struvite pellets were crushed into powder to be analysed by X-ray Diffraction (XRD), to confirm struvite crystal formation and to check the purity. The images in Figures 4.58 and 4.59, illustrated a confirmation of pure struvite pellet formation in both combinations, as the peaks and intensities of the struvite samples matched with the peaks and intensities of known struvite crystal structure in the XRD database. Furthermore, a chemical analysis was performed on the crushed powdered samples of struvite pellets, by solubilising in acid and testing for Mg:NH4-N:PO4-P molar ratio. Results are presented in Table 4.7. Table 4.7: Chemical analysis results of struvite pellets  Chemical analysis results showed the formation of pure struvite pellets, containing Mg, NH4-N, PO4-P and water as follows: MgxNH4yPO4znH2O, where x=1.0-1.09, y=0.89-0.94, z=1.0, n=6.76-7.23. Therefore, both XRD and Chemical analysis indicated that pure struvite pellets were formed in both combinations. However, XRD analysis of 0.125 mm and fine samples Solid Sample Size Pre-Anammox Struvite Pellets  (Centrate Feed) Post-Anammox Struvite Pellets (Anammox Effluent Feed) molar ratios molar ratios Mg NH4 PO4 H2O Mg NH4 PO4 H2O 4mm 1.02 0.94 1.00 6.98 1.02 0.92 1.00 6.76 2mm 1.07 0.92 1.00 7.08 1.02 0.90 1.00 6.79 1mm 1.08 0.90 1.00 7.23 1.00 0.90 1.00 6.79 0.5mm 1.09 0.89 1.00 7.13 1.03 0.90 1.00 6.98 0.125 mm 1.02 0.89 1.00 6.82 1.02 0.89 1.00 6.76 Fines 1.04 0.89 1.00 6.95 1.01 0.89 1.00 7.13 Results and Discussion  119  indicated a negligible amount of impurities present in post-anammox-struvite process, presumed to be newberyite because of the low N: P molar ratio. Also, the struvite pellets harvested in combination 1 (with centrate feed) seemed harder (when crushed by hand) and glazy (visible with the eye and under the microscope (10X), as seen in Figures 4.60 and 4.61)  Figure 4.60: Physical properties of Pre-Anammox-Struvite pellets (2mm size)     Figure 4.61: Physical properties of Post-Anammox-Struvite pellets (2mm size) Conclusions and Recommendations  120  5 Conclusions and Recommendations 5.1 Conclusions In order to answer the research questions set at the beginning of the study, several parameters were tested under different experimental conditions. Some basic conclusions can be drawn as follows: • The struvite precipitation process was successfully combined with the UniBAR-anammox process at pilot-scale with an average combined N-removal of more than 70% and average combined P-removal of over 90%, in both combination sequences. • In Pre-Anammox-Struvite process (combination 1), an average combined P-removal efficiency of 90.8±1.8 % (maximum 97.5%) was achieved by struvite precipitation with UBC crystallizer, with negligible caustic consumption. • An average N-removal efficiency in the UniBAR-anammox process was 76.2±1.0% with centrate feed and 70±1.1% with struvite effluent feed. In the combined process, with an additional 9.1±1.6% of N-removal by struvite precipitation process, an average combined N-removal was achieved at 79.2 ± 1.9%. • There were no significant changes observed in the UniBAR-anammox reactor characteristics before (centrate feed) and after (struvite effluent feed) combination in the continuous run. Over 70% N-removal was achieved in both cases. Conclusions and Recommendations  121  • Batch test results with centrate and struvite effluent feed at different temperatures (34  , 30  , 25  C) also confirmed the findings from the continuous process run. The anammox process, with both feeds, showed similar behavioral pattern with better performance at higher temperature (34  C). • Time requirements for completing one cycle test, with batch feed, increased with a decrease in temperature. For centrate feed, this cycle completion took 23.5 h, 25.5 h and 29 h at 34  , 30    n  25  C, respectively; whereas, for struvite effluent feed, 23 h, 26 h and 28.5 h were needed for the complete cycle. • The N-removal efficiency with centrate feed was 70.1%, 61% and 57.5% while efficiency of 70.4%, 60% and 56.4% was achieved with struvite effluent feed, at 34  , 30    n  25  C, respectively. These results indicated that removal efficiencies were similar with both feeds at a certain temperature; also, an increase in operating temperature increased removal efficiency. • Batch tests of the UniBAR-an mmox      o     low     mp         20  C) was unsuccessful at the existed operating conditions, due to higher nitrite built up in the reactor. The reactor failed within 8 h of experiment start up. • In combination 2 (Post-Anammox-Struvite process), N-removal efficiency in UniBAR-anammox process with centrate feed was 60.1±6.2%. In the combined process, anammox effluent was fed to the UBC struvite crystallizer, where average 10.9±2.9% additional N-removal was achieved by the struvite precipitation process resulted in combined N-removal of 71.0±5.2% on average. Conclusions and Recommendations  122  • The average combined P-removal efficiency of 90.8±1.8 % was achieved by struvite precipitation, before combination with centrate feed, at a pH set point of 7.67. This was statistically the same after combination with anammox effluent feed (92.7±3.8%) at pH of 8.30. • With an increased pH set point in the struvite column, it can be said that struvite precipitation process was not affected by the change in influent (from centrate to anammox effluent). However, keeping the pH set point at 7.67, the average P-removal with anammox effluent feed was decreased (74.6±2.5%), from an average of 90.8±2.8% with centrate feed. Therefore, the struvite precipitation process was actually affected by the anammox effluent, due to the lower N: P molar ratio in the anammox effluent feed.  • In order to achieve the same P-removal efficiency after combination, the pH set point was increased with consequently higher caustic consumption; this increases chemical as well as overall operating costs. Also, at a certain pH of 8.30, caustic consumption increased with the decrease in N: P ratio, to maintain a desired SSR. • Successful nutrient recovery as pure struvite pellets (0.125 mm to 4 mm) was achieved in both Pre and Post Anammox Struvite Precipitation processes, as confirmed by XRD and chemical analysis. 5.2 Recommendations for Future Work After the successful process combinations, this unified solution for managing wastewater nutrients may attract more attention and there are several scopes for future research. Some recommendations are as follows: Conclusions and Recommendations  123   In combination 2 of this study, anammox effluent was stored in a tank to ensure enough feed for the struvite column, as anammox is a slow microbial process but struvite is a quick chemical process. Instead of storing the anammox effluent, the struvite feed rate can be matched with the anammox effluent flow rate, by adjusting the recycle ratio and determining the removal efficiencies.  Also, because of the stored anammox effluent feeding into the struvite reactor, the operation was at room temperature in this study. Hence, in future studies without the storage tank, temperature effects needs to be studied for struvite precipitation, as the anammox effluent will hav    high   mp         30-34  )   In combination 1, the anammox reactor was of bench scale (10.8 L), resulting in 70% of N removal with both centrate and struvite effluent feed. The only reason behind using this reactor was that both of the combinations were running simultaneously and another pilot-scale, anammox process setup was not available at that moment. Therefore, using a pilot-scale setup for the anammox process in combination 1 is recommended for future studies, to verify the results obtained in this study.   Since N-removal in anammox process was around 70% with both centrate and struvite effluent feeds, another combination can be considered (Anammox reactor-Struvite column-Anammox reactor) to remove the remaining 30% of N.    References  124  References Aage, H.K., Andersen, B.L., Blom, A., Jensen, I., 1997. The solubility of struvite. J. Radioanal. Nucl. Chem. 223, 213–215. doi:10.1007/BF02223387 Adnan, A., 2002. Pilot-scale study of phosphorus recovery through struvite crystallization. M. A. Sc. Thesis, Department of Civil Engineering, University of British Columbia, Vancouver, BC, Canada. Aneja, V.P., Blunden, J., Roelle, P.A., Schlesinger, W.H., Knighton, R., Niyogi, D., Gilliam, W., Jennings, G., Duke, C.S., 2008. Workshop on agricultural air quality: state of the science. Atmos. 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B 9, 416–426. doi:10.1631/jzus.B0710590 Appendix A 133  Appendices   Appendix A 134  Appendix A: Calculations for Upflow Velocity and Reynolds Number  Upflow velocity = Flow rate/cross sectional area Flow rate = Feed flow + Recycle flow Recycle Ratio = Recycle flow rate/ Feed flow rate Flow rate calculation is shown in Table A.1 Table A.1: Flow rate calculations in the struvite reactor Recycle ratio 5.0   Feed flow rate 340 ml/min Recycle flow rate 1700.0 ml/min Total upflow rate 2040.0 ml/min  Reynolds number is given by the equation (Metcalf & Eddy et al., 2003), Reynolds number= ρVD/µ   Where,  ρ= mass density of the fluid, kg/m3 V= average velocity of the fluid, m/s D= diameter, m µ= viscosity of the fluid, Ns/m2        mp        o  25  ,  h  v l    o  ρ and µ are 997 kg/m3 and 8.9 x10-4 Ns/m2 respectively (Fattah, 2004; Metcalf & Eddy et al., 2003). Appendix A 135  Upflow velocity and Reynolds number are calculated in Table A.2  Table A.2: Upflow velocity and Reynolds number in the reactor Sections Inside diameter Area Flow rate Upflow velocity Re HRT   cm cm2 L/min cm/min   min Harvest 2.54 5.07 2.04 402.60 1909.24 7.21 Active 3.81 11.40 cc/min 178.93 1272.82   fines 7.62 45.60 2040.00 44.73 636.41   seed hopper 19.05 285.02 L/d 7.16 254.56   Below harvest zone (Injection port included) 2.54 5.07 2937.60       Total                   Appendix B 136  Appendix B: XRD Analysis Results of Struvite Pellets                  Appendix B 137   Figure B.1: XRD analysis result of Post-Anammox-Struvite pellets (0.125 mm)   Figure B.2: XRD analysis result of Pre-Anammox-Struvite pellets (0.125 mm)  Anammox to struvite 0.25 mm00-015-0762 (*) - Struvite, syn - NH4MgPO4·6H2O - Y: 90.78 % - d x by: 1. - WL: 1.5406 - Orthorhombic - a 6.94500 - b 11.20800 - c 6.13550 - alpha 90.000 - beta 90.000 - gamma 90.000 - Primitive - Operations: ImportFile: A-S_025.raw - Start: 5.000 ° - End: 64.994 ° - Step: 0.019 ° - Step time: 36.4 s - Anode: Cu - WL1: 1.5406 - WL2: 1.54439 - kA2 Ratio: 0.5 - Generator kV: 40 kV - Generator mA: 40 mALin (Counts)0100020003000400050006000700080009000100001100012000130001400015000160001700018000190002000021000220002300024000250002-Theta - Scale5 10 20 30 40 50 600.5 mm struvite00-015-0762 (*) - Struvite, syn - NH4MgPO4·6H2O - Y: 51.16 % - d x by: 1. - WL: 1.5406 - Orthorhombic - a 6.94500 - b 11.20800 - c 6.13550 - alpha 90.000 - beta 90.000 - gamma 90.000 - Primitive - Operations: ImportFile: Sifat05.raw - Start: 5.000 ° - End: 75.079 ° - Step: 0.010 ° - Step time: 36.4 s - Anode: Cu - WL1: 1.5406 - WL2: 1.54439 - kA2 Ratio: 0.5 - Generator kV: 40 kV - Generator mA: 40 mALin (Counts)010002000300040005000600070008000900010000110001200013000140001500016000170001800019000200002100022000232425262-Theta - Scale5 10 20 30 40 50 60 70Appendix B 138   Figure B.3: XRD analysis result of Pre-Anammox-Struvite pellets (0.5 mm)   Figure B.4: XRD analysis result of Post-Anammox-Struvite pellets (0.5 mm) 0.5 mm struvite00-015-0762 (*) - Struvite, syn - NH4MgPO4·6H2O - Y: 51.16 % - d x by: 1. - WL: 1.5406 - Orthorhombic - a 6.94500 - b 11.20800 - c 6.13550 - alpha 90.000 - beta 90.000 - gamma 90.000 - Primitive - Operations: ImportFile: Sifat05.raw - Start: 5.000 ° - End: 75.079 ° - Step: 0.010 ° - Step time: 36.4 s - Anode: Cu - WL1: 1.5406 - WL2: 1.54439 - kA2 Ratio: 0.5 - Generator kV: 40 kV - Generator mA: 40 mALin (Counts)010002000300040005000600070008000900010000110001200013000140001500016000170001800019000200002100022000230002400025000260002-Theta - Scale5 10 20 30 40 50 60 70Anammox to struvite 0.5 mm00-015-0762 (*) - Struvite, syn - NH4MgPO4·6H2O - Y: 63.40 % - d x by: 1. - WL: 1.5406 - Orthorhombic - a 6.94500 - b 11.20800 - c 6.13550 - alpha 90.000 - beta 90.000 - gamma 90.000 - Primitive - Operations: ImportFile: A-S_050.raw - Start: 5.000 ° - End: 64.994 ° - Step: 0.019 ° - Step time: 36.4 s - Anode: Cu - WL1: 1.5406 - WL2: 1.54439 - kA2 Ratio: 0.5 - Generator kV: 40 kV - Generator mA: 40 mALin (Counts)0100020003000400050006000700080009000100001100012000130001400015000160001700018000190002000021222300024000250002600027000222-Theta - Scale5 10 20 30 40 50 60Appendix B 139   Figure B.5: XRD analysis result of Pre-Anammox-Struvite pellets (1.0 mm)   Figure B.6: XRD analysis result of Post-Anammox-Struvite pellets (1.0 mm) 1 mm struvite00-015-0762 (*) - Struvite, syn - NH4MgPO4·6H2O - Y: 56.42 % - d x by: 1. - WL: 1.5406 - Orthorhombic - a 6.94500 - b 11.20800 - c 6.13550 - alpha 90.000 - beta 90.000 - gamma 90.000 - Primitive - Operations: ImportFile: Sifat1.raw - Start: 5.000 ° - End: 75.079 ° - Step: 0.010 ° - Step time: 36.4 s - Anode: Cu - WL1: 1.5406 - WL2: 1.54439 - kA2 Ratio: 0.5 - Generator kV: 40 kV - Generator mA: 40 mALin (Counts)01000200030004000500060007000800090001000011000120001300014000150001600017000180001900020000210002200023000240002500026000270002-Theta - Scale5 10 20 30 40 50 60 70Anammox to struvite 1 mm00-015-0762 (*) - Struvite, syn - NH4MgPO4·6H2O - Y: 87.09 % - d x by: 1. - WL: 1.5406 - Orthorhombic - a 6.94500 - b 11.20800 - c 6.13550 - alpha 90.000 - beta 90.000 - gamma 90.000 - Primitive - Operations: ImportFile: A-S_100.raw - Start: 5.000 ° - End: 64.994 ° - Step: 0.019 ° - Step time: 36.4 s - Anode: Cu - WL1: 1.5406 - WL2: 1.54439 - kA2 Ratio: 0.5 - Generator kV: 40 kV - Generator mA: 40 mALin (Counts)0100020003000400050006000700080009000100001100012000130001400015000160001700018000190002000021222324562-Theta - Scale5 10 20 30 40 50 60Appendix B 140   Figure B.7: XRD analysis result of Pre-Anammox-Struvite pellets (2.0 mm)   Figure B.8: XRD analysis result of Post-Anammox-Struvite pellets (2.0 mm) 2 mm struvite00-015-0762 (*) - Struvite, syn - NH4MgPO4·6H2O - Y: 36.76 % - d x by: 1. - WL: 1.5406 - Orthorhombic - a 6.94500 - b 11.20800 - c 6.13550 - alpha 90.000 - beta 90.000 - gamma 90.000 - Primitive - Operations: ImportFile: Sifat2.raw - Start: 5.000 ° - End: 75.079 ° - Step: 0.010 ° - Step time: 36.4 s - Anode: Cu - WL1: 1.5406 - WL2: 1.54439 - kA2 Ratio: 0.5 - Generator kV: 40 kV - Generator mA: 40 mALin (Counts)0100020003000400050006000700080009000100001100012000130001400015000160001700018000190002000021000220002300024000250002600027000280002900030000310002-Theta - Scale5 10 20 30 40 50 60 70Anammox to struvite 2 mm00-015-0762 (*) - Struvite, syn - NH4MgPO4·6H2O - Y: 84.63 % - d x by: 1. - WL: 1.5406 - Orthorhombic - a 6.94500 - b 11.20800 - c 6.13550 - alpha 90.000 - beta 90.000 - gamma 90.000 - Primitive - Operations: ImportFile: A-S_200.raw - Start: 5.000 ° - End: 64.994 ° - Step: 0.019 ° - Step time: 36.4 s - Anode: Cu - WL1: 1.5406 - WL2: 1.54439 - kA2 Ratio: 0.5 - Generator kV: 40 kV - Generator mA: 40 mALin (Counts)01000200030004000500060007000890001000011000120001300014000150001600078190002000021000223000240002500067280002-Theta - Scale6 10 20 30 40 50 60Appendix B 141   Figure B.9: XRD analysis result of Pre-Anammox-Struvite pellets (4.0 mm)   Figure B.10: XRD analysis results of Post-Anammox-Struvite pellets (4.0 mm) 4 mm struvite00-015-0762 (*) - Struvite, syn - NH4MgPO4·6H2O - Y: 51.98 % - d x by: 1. - WL: 1.5406 - Orthorhombic - a 6.94500 - b 11.20800 - c 6.13550 - alpha 90.000 - beta 90.000 - gamma 90.000 - Primitive - Operations: ImportFile: Sifat4.raw - Start: 5.000 ° - End: 75.079 ° - Step: 0.010 ° - Step time: 36.4 s - Anode: Cu - WL1: 1.5406 - WL2: 1.54439 - kA2 Ratio: 0.5 - Generator kV: 40 kV - Generator mA: 40 mALin (Counts)01000200030004000500060007000800090001000011000120001300014000150001600017000180001900020000210002200023000240002500026000270002800029000300002-Theta - Scale5 10 20 30 40 50 60 704 mm struvite00-015-0762 (*) - Struvite, syn - NH4MgPO4·6H2O - Y: 51.98 % - d x by: 1. - WL: 1.5406 - Orthorhombic - a 6.94500 - b 11.20800 - c 6.13550 - alpha 90.000 - beta 90.000 - gamma 90.000 - Primitive - Operations: ImportFile: Sifat4.raw - Start: 5.000 ° - End: 75.079 ° - Step: 0.010 ° - Step time: 36.4 s - Anode: Cu - WL1: 1.5406 - WL2: 1.54439 - kA2 Ratio: 0.5 - Generator kV: 40 kV - Generator mA: 40 mALin (Counts)0100020003000400050006000700089000100001100012000130001400015000678920000210002200023000240002500026000789302-Theta - Scale5 10 20 30 40 50 60 70Appendix C 142  Appendix C: Data Sheet            Appendix C 143  Table C.1: Struvite Precipitation Process Data with Centrate Feed (Combination 1)   Struvite Influent Struvite Effluent     Date pH  Alkalinity (mg/L) NH4-N (mg/L) PO4-P (mg/L) TSS (mg/L) VSS (mg/L) pH  Alkalinity (mg/L) NH4-N (mg/L) PO4-P (mg/L) TSS (mg/L) VSS (mg/L) N-removal (%) P-removal (%) 27-Jan-14 8.13  N/A     N/A N/A      28-Jan-14 8.01 2365.00 N/A     N/A 588.00 3.33   N/A N/A 3-Feb-14 7.79 2924.00 780.00 77.80   8.11 3191.00 606.00 7.49 350 220 22.31 90.37 4-Feb-14 8.01 2724.00 807.00 90.10 210 170 8.09 2680.00 603.00 3.01 380 210 25.28 96.66 18-Feb-14 7.79 2467.90 895.00 133.90 210 170 8.01 2485.50 792.00 30.10 230 200 11.51 77.52 19-Feb-14 7.78 2615.70 958.00 130.00 240 180 7.99 2547.40 872.00 14.50 220 200 8.98 88.85 20-Feb-14 8.00 2804.70 1060.00 136.00 220 180 7.98 2863.60 1030.0 22.50 230 170 2.83 83.46 21-Feb-14 8.00 2698.80 1061.00 133.00 260 200 7.95 2792.20 960.00 12.40 230 180 9.52 90.68 26-Feb-14 8.04 2284.00 705.00 124.00 300 250 7.98 2382.00 591.00 10.30 280 210 16.17 91.69 28-Feb-14 8.07 2781.00 781.00 112.00 270 220 7.87 2521.00 734.00 8.50 290 230 6.02 92.41 1-Mar-14 8.05 2840.00 776.20 115.00 260 230 7.99 2642.00 730.40 7.10 280 240 5.90 93.83 2-Mar-14 8.01 2670.00 785.30 113.50 270 240 7.88 2580.00 745.87 16.40 250 220 5.02 85.55 3-Mar-14 7.95 2760.00 810.00 114.00 250 210 7.85 2635.00 751.33 14.20 260 210 7.24 87.54 10-Mar-14 7.78 2890.00 794.88 114.50 240 200 7.76 2748.00 735.79 25.45 260 190 7.43 77.77 11-Mar-14 7.92 2904.00 814.06 119.00 200 180 7.74 2624.00 786.79 12.05 240 210 3.35 89.87 12-Mar-14 7.94 2900.00 806.99 119.00 210 170 7.96 2490.00 748.41 6.32 240 220 7.26 94.69 13-Mar-14 7.96 3030.00 795.90 106.00 200 180 7.91 2453.00 755.99 3.52 220 250 5.02 96.68 14-Mar-14 7.96 3043.00 852.46 117.00 190 170 7.97 2530.00 733.26 3.83 240 250 13.98 96.73 19-Mar-14 7.97 3004.00 862.26 126.00 220 190 7.89 2377.00 749.42 3.39 220 220 13.09 97.31 20-Mar-14 7.89 3093.00 874.17 122.00 180 160 7.84 2375.00 774.67 3.01 200 230 11.38 97.54 21-Mar-14 7.90 3063.00 927.20 117.00 190 170 7.77 2550.00 775.18 3.77 210 220 16.40 96.78 Appendix C 144   Struvite Influent Struvite Effluent   Date pH  Alkalinity (mg/L) NH4-N (mg/L) PO4-P (mg/L) TSS (mg/L) VSS (mg/L) pH  Alkalinity (mg/L) NH4-N (mg/L) PO4-P (mg/L) TSS (mg/L) VSS (mg/L) N-removal (%) P-removal (%) 7-Apr-14 8.20 1861.00 671.50 68.40 190 160 8.09 1681.00 491.90 5.95 180 190 26.75 91.30 8-Apr-14 8.19 1775.00 681.50 67.56 190 160 8.07 1405.00 468.30 10.85 200 160 31.28 83.94 9-Apr-14 8.10 1763.00 699.50 70.14 230 150 8.04 1622.00 558.70 19.95 210 190 20.13 71.56 10-Apr-14 8.09 1791.00 703.50 68.82 160 110 8.02 1561.00 400.50 6.27 180 160 43.07 90.89 11-Apr-14 8.07 1731.00 743.00 82.26 140 120 7.99 1546.00 442.00 8.43 200 140 40.51 89.75 15-Apr-14 8.13 2280.00 778.00 84.72 200 190 8.05 2082.00 501.00 10.98 180 160 35.60 87.04 16-Apr-14 8.08 2421.00 789.50 94.38 240 200 7.98 2096.00 584.50 12.75 250 210 25.97 86.49 17-Apr-14 8.13 2470.00 752.50 95.18 230 180 7.99 2095.00 576.00 19.86 260 210 23.46 79.13 6-May-14 8.09 2871.00 715.41 93.45 210 160 8.05 2756.00 610.04 8.97 230 200 14.73 90.40 7-May-14 8.03 3021.00 722.68 89.40 230 190 7.98 2397.00 570.15 16.80 240 190 21.11 81.21 8-May-14 8.02 2869.00 786.79 90.15 250 220 7.94 2850.00 707.51 25.70 260 210 10.08 71.49 9-May-14 8.05 2850.00 731.75 104.69 240 200 7.96 2861.00 723.69 20.01 230 180 1.10 80.89 14-May-14 8.19 3700.00 724.17 107.42 280 240 7.99 2784.00 639.30 13.35 250 200 11.72 87.57 15-May-14 8.05 3777.00 1013.54 140.25 240 220 7.97 3465.00 930.72 12.74 300 290 8.17 90.92 16-May-14 8.03 3693.00 990.30 132.20 260 250 7.96 3436.40 972.13 10.55 290 250 1.84 92.02 19-May-14 7.99 3691.00 1041.82 145.75 230 210 7.94 3412.00 927.18 14.68 310 270 11.00 89.93 20-May-14 7.97 3716.00 1001.00 134.85 240 220 7.96 3611.00 998.39 9.24 260 240 0.26 93.15 21-May-14 7.96 3765.00 1035.25 145.20 290 250 7.95 3624.50 986.27 12.95 270 230 4.73 91.08 22-May-14 7.94 3716.00 989.30 136.75 310 280 7.80 3146.00 929.20 11.11 300 240 6.07 91.88 24-May-14 7.88 3736.00 898.90 138.40 300 270 7.78 3128.00 654.99 15.15 280 190 27.13 89.05 28-May-14 7.86 2721.00 794.87 125.65 250 210 7.76 2726.00 669.63 9.96 260 180 15.76 92.07 29-May-14 7.88 2592.00 735.79 118.65 230 180 7.67 2501.00 665.09 9.33 230 200 9.61 92.14 Appendix C 145  Struvite Influent Struvite Effluent   Date pH  Alkalinity (mg/L) NH4-N (mg/L) PO4-P (mg/L) TSS (mg/L) VSS (mg/L) pH  Alkalinity (mg/L) NH4-N (mg/L) PO4-P (mg/L) TSS (mg/L) VSS (mg/L) N-removal (%) P-removal (%) 30-May-14 7.85 2585.40 661.27 90.37 300 240 7.68 2464.00 430.77 11.16 300 190 34.86 87.65 2-Jun-14 7.91 2711.90 688.94 110.55 250 190 7.78 2537.00 575.20 6.92 310 200 16.51 93.74 3-Jun-14 7.94 2595.80 735.40 112.25 240 160 7.74 2398.00 555.00 5.05 220 160 24.53 95.50 4-Jun-14 7.92 2258.00 697.48 115.10 210 140 7.78 2270.00 552.47 7.15 200 140 20.79 93.79 5-Jun-14 7.78 2582.00 765.19 111.24 230 170 7.67 2349.00 618.12 12.23 260 180 19.22 89.01 7-Jun-14 7.74 2605.00 670.23 107.49 210 140 7.69 2393.00 661.55 8.92 240 210 1.30 91.70 12-Jun-14 7.79 2584.00 699.22 114.70 160 130 7.68 2288.00 646.91 9.48 180 150 7.48 91.73 13-Jun-14 7.80 2709.00 654.20 104.45 180 160 7.75 2275.00 621.16 8.29 200 180 5.05 92.06  Table C.2: Struvite Precipitation Process Data with Anammox Effluent Feed (Combination 2)   Struvite Influent Struvite Effluent     Date pH  Alkalinity (mg/L) NH4-N (mg/L) PO4-P (mg/L) TSS (mg/L) VSS (mg/L) pH  Alkalinity (mg/L) NH4-N (mg/L) PO4-P (mg/L) TSS (mg/L) VSS (mg/L) N-removal (%) P-removal (%) 26-Aug-14 6.79 161.75 203.50 118.90 90 80 7.35 169.52 190.65 44.40 80 70 6.31 62.66 27-Aug-14 6.72 163.13 191.95 122.40 90 80 7.22 141.62 176.48 42.05 110 90 8.06 65.65 28-Aug-14 6.72 173.87 140.20 126.60 110 90 7.13 158.01 145.10 33.86 70 80 -3.50 73.25 29-Aug-14 6.71 167.50 155.71 124.60 120 110 7.15 158.13 148.96 35.68 130 100 4.33 71.36 30-Aug-14 6.68 160.17 177.64 125.74 150 100 7.10 159.40 164.60 37.41 120 90 7.34 70.25 2-Sep-14 6.67 124.53 200.20 128.70 140 110 7.16 176.54 155.90 29.71 130 120 22.13 76.92 3-Sep-14 6.25 118.31 231.55 132.00 350 110 7.30 125.08 193.00 33.91 330 120 16.65 74.31 4-Sep-14 6.19 110.23 234.85 132.90 310 210 7.11 127.47 204.40 34.31 300 190 12.97 74.18 16-Sep-14 6.72 177.45 248.60 122.20 320 220 7.35 186.42 279.40 34.58 320 120 12.39 71.70 Appendix C 146   Struvite Influent Struvite Effluent   Date pH  Alkalinity (mg/L) NH4-N (mg/L) PO4-P (mg/L) TSS (mg/L) VSS (mg/L) pH  Alkalinity (mg/L) NH4-N (mg/L) PO4-P (mg/L) TSS (mg/L) VSS (mg/L) N-removal (%) P-removal (%) 17-Sep-14 6.68 182.72 331.10 128.10 370 170 7.24 168.94 277.59 22.38 350 150 16.16 82.53 18-Sep-14 6.72 194.85 325.70 139.20 390 150 7.31 177.58 287.05 22.12 390 150 11.87 84.11 19-Sep-14 6.74 189.39 330.74 141.90 360 160 7.37 167.07 269.90 26.32 350 150 18.40 81.45 20-Sep-14 6.61 188.90 359.15 132.30 310 150 7.23 165.30 295.25 36.16 270 140 17.79 72.67 21-Sep-14 6.67 174.92 356.10 128.70 290 160 7.26 185.64 285.20 25.64 310 150 19.91 80.08 23-Sep-14 6.69 175.43 342.10 127.50 340 170 7.26 192.47 255.25 32.78 310 160 25.39 74.29 24-Sep-14 6.69 156.87 312.26 127.80 360 160 7.35 186.36 280.55 30.76 330 150 10.15 75.93 25-Sep-14 6.67 152.76 355.60 125.40 330 130 7.31 174.83 298.35 25.53 340 140 16.10 79.64 28-Sep-14 6.63 157.32 360.42 130.20 280 180 7.57 171.10 309.10 36.50 290 160 14.24 71.97 29-Sep-14 6.62 158.27 376.75 130.80 270 160 7.37 178.02 369.65 30.80 250 170 1.88 76.45 5-Oct-14 6.83 163.92 274.35 114.40 260 160 8.67 152.43 255.95 18.17 280 160 6.71 84.12 6-Oct-14 7.01 194.98 290.75 119.70 380 180 8.53 208.01 264.20 14.94 340 150 9.13 87.52 7-Oct-14 6.92 194.65 238.70 116.10 370 170 8.51 209.97 262.90 4.21 370 130 10.14 96.38 8-Oct-14 6.85 191.53 253.00 121.50 360 160 8.44 211.46 223.65 2.03 340 130 11.60 98.33 9-Oct-14 6.82 188.27 247.50 115.80 370 150 8.26 182.19 214.15 1.68 450 140 70.00 30.00 17-Oct-14 6.80 195.31 213.95 103.80 100 20 8.23 187.36 182.05 10.80 210 70 40.00 20.00 18-Oct-14 6.79 192.36 253.00 112.20 -20 20 8.35 179.02 203.50 8.76   40.00 10.00    Appendix C 147  Table C.3: UniBAR-anammox Process Operating Condition Data from Start up to System Optimization with Centrate Feed (Combination 1) Operating Conditions of UniBAR-anammox Process (Centrate Feed) Date Remarks Air Flow Rate (LPM) Air pump Timer Feed consumption rate (L/d) HRT (d) 15-Nov-13 Start up 0.5 30 min ON, 15 min OFF 1.84 5.87 19-Nov-13  0.5 30 min ON, 15 min OFF 1.92 5.63 22-Nov-13  0.5 30 min ON, 15 min OFF 3.69 2.93 25-Nov-13 Airflow increased 1.6 30 min ON, 15 min OFF 6.80 1.59 29-Nov-13 Reactor Failed OFF 30 min ON, 15 min OFF   1-Dec-13 Restarted reactor 0.5 30 min ON, 15 min OFF   3-Dec-13  0.5 30 min ON, 15 min OFF 5.40 2.00 11-Dec-13  0.5 30 min ON, 15 min OFF 6.20 1.74 13-Dec-13 Reactor Failed OFF 30 min ON, 15 min OFF   14-Dec-13 Restarted reactor 0.5 30 min ON, 15 min OFF 2.74 3.94 17-Dec-13  0.5 30 min ON, 15 min OFF 3.10 3.48 20-Dec-13  0.5 30 min ON, 15 min OFF 3.45 3.13 27-Dec-13  0.5 30 min ON, 15 min OFF 3.58 3.02 2-Jan-14 Increasing air to reduce HRT 1.0 20 min ON, 10 min OFF 3.84 2.81 3-Jan-14  1.0 20 min ON, 10 min OFF 3.96 2.73 6-Jan-14 Increasing air to reduce HRT 1 to 1.4 30 min ON, 15 min OFF 3.75 2.88 10-Jan-14  1 to 1.4 30 min ON, 15 min OFF 3.89 2.78 13-Jan-14  1 to 1.4 30 min ON, 15 min OFF 3.60 3.00 15-Jan-14  1 to 1.4 30 min ON, 15 min OFF 3.46 3.12 17-Jan-14  1 to 1.4 30 min ON, 15 min OFF 3.68 2.94 Appendix C 148  Operating Conditions of UniBAR-anammox Process (Centrate Feed) Date Remarks Air Flow Rate (LPM) Air pump Timer Feed consumption rate (L/d) HRT (d) 20-Jan-14  1 to 1.4 30 min ON, 15 min OFF 3.50 3.09 23-Jan-14  1 to 1.4 30 min ON, 15 min OFF 3.40 3.18 27-Jan-14  1 to 1.4 30min ON, 15 min OFF 2.88 3.75 3-Feb-14 reduced air 1.0 30min ON, 15 min OFF 3.46 3.12 5-Feb-14  1.0 30min ON, 15 min OFF 2.60 4.16 11-Feb-14 Air back to 1.0-1.4 LPM 1 to 1.4 30min ON, 20 min OFF 2.77 3.90 13-Feb-14  1 to 1.4 30min ON, 20 min OFF 3.03 3.57 18-Feb-14 Optimized Condition 1 to 1.4 30min ON, 20 min OFF 2.25 4.80 19-Feb-14  1 to 1.4 30min ON, 20 min OFF 2.25 4.80 20-Feb-14  1 to 1.4 30min ON, 20 min OFF 2.36 4.57 21-Feb-14  1 to 1.4 30min ON, 20 min OFF 2.60 4.16 24-Feb-14  1 to 1.4 30min ON, 20 min OFF 2.31 4.68 26-Feb-14  1 to 1.4 30min ON, 20 min OFF 2.16 4.99 27-Feb-14  1 to 1.4 30min ON, 20 min OFF 2.16 4.99 28-Feb-14  1 to 1.4 30min ON, 20 min OFF 2.60 4.16 5-Mar-14  1 to 1.4 30min ON, 20 min OFF 2.42 4.46 7-Mar-14  1 to 1.4 30min ON, 20 min OFF 3.03 3.57 10-Mar-14  1 to 1.4 30min ON, 20 min OFF 2.31 4.68 12-Mar-14  1 to 1.4 30min ON, 20 min OFF 2.38 4.54 13-Mar-14  1 to 1.4 30min ON, 20 min OFF 2.25 4.80 19-Mar-14  1 to 1.4 30min ON, 20 min OFF 2.25 4.80 20-Mar-14  1 to 1.4 30min ON, 20 min OFF 2.60 4.15 21-Mar-14  1 to 1.4 30min ON, 20 min OFF 2.60 4.15 24-Mar-14  1to 1.4 30min ON, 20 min OFF 2.60 4.15 Appendix C 149  Table C.4: UniBAR-anammox Process Operating Condition Data in the Optimized System with Struvite Effluent Feed (Combination 1) Operating Conditions of UniBAR-anammox Process (Struvite Effluent Feed) Date Remarks Air Flow Rate (LPM) Air pump Timer Feed consumption rate (L/d) HRT (d) 7-Apr-14 Combined process (Optimized condition) 1 to 1.4 30min ON, 20 min OFF 1.73 6.24 8-Apr-14  1 to 1.4 30min ON, 20 min OFF 2.50 4.32 9-Apr-14  1 to 1.4 30min ON, 20 min OFF 2.10 5.14 10-Apr-14  1 to 1.4 30min ON, 20 min OFF 1.90 5.68 11-Apr-14  1 to 1.4 30min ON, 20 min OFF 1.60 6.75 15-Apr-14  1 to 1.4 30min ON, 20 min OFF 1.50 7.20 16-Apr-14  1 to 1.4 30min ON, 20 min OFF 1.50 7.20 17-Apr-14  1 to 1.4 30min ON, 20 min OFF 1.90 5.68 29-Apr-14  1 to 1.4 30min ON, 20 min OFF 2.14 5.05 1-May-14  1 to 1.4 30min ON, 20 min OFF 2.50 4.32 5-May-14  1 to 1.4 30min ON, 20 min OFF 2.80 3.86 6-May-14  1 to 1.4 30min ON, 20 min OFF 3.00 3.60 7-May-14  1 to 1.4 30min ON, 20 min OFF 2.60 4.15 8-May-14  1 to 1.4 30min ON, 20 min OFF 2.80 3.86 9-May-14  1 to 1.4 30min ON, 20 min OFF 3.00 3.60 14-May-14  1 to 1.4 30min ON, 20 min OFF   16-May-14  1 to 1.4 30min ON, 20 min OFF   Appendix C 150  Operating Conditions of UniBAR-anammox Process (Struvite Effluent Feed) Date Remarks Air Flow Rate (LPM) Air pump Timer Feed consumption rate (L/d) HRT (d) 19-May-14  1 to 1.4 30min ON, 20 min OFF   20-May-14  1 to 1.4 30min ON, 20 min OFF   21-May-14  1 to 1.4 30min ON, 20 min OFF   22-May-14  1 to 1.4 30min ON, 20 min OFF   24-May-14  1 to 1.4 30min ON, 20 min OFF 1.25 8.64 28-May-14  1 to 1.4 30min ON, 20 min OFF 1.75 6.17 29-May-14  1 to 1.4 30min ON, 20 min OFF 1.75 6.17 30-May-14  1 to 1.4 30min ON, 20 min OFF 2.50 4.32 2-Jun-14  1 to 1.4 30min ON, 20 min OFF 1.75 6.17 3-Jun-14  1 to 1.4 30min ON, 20 min OFF 1.00 10.80 4-Jun-14  1 to 1.4 30min ON, 20 min OFF   5-Jun-14  1 to 1.4 30min ON, 20 min OFF   7-Jun-14  1 to 1.4 30min ON, 20 min OFF 5.19 2.08 12-Jun-14 Introducing new air pump 1 to 1.4 30min ON, 20 min OFF 5.21 2.07 13-Jun-14 Failed due to high air flow OFF  5.48 1.97 16-Jun-14 Restarted reactor 1 to 1.4 30min ON, 20 min OFF 5.73 1.88 18-Jun-14      20-Jun-14      23-Jun-14 Stabilized reactor 1 to 1.4 30min ON, 20 min OFF 4.73 2.28 24-Jun-14    6.06 1.78 Appendix C 151  Operating Conditions of UniBAR-anammox Process (Struvite Effluent Feed) Date Remarks Air Flow Rate (LPM) Air pump Timer Feed consumption rate (L/d) HRT (d) 25-Jun-14    4.33 2.50 28-Jun-14 Reactor Failed, NO2 built up OFF    30-Jun-14 Restarted with fresh sludge 1 to 1.4 10 min ON, 40 min Off 2.45 4.41 4-Jul-14    2.88 3.75 7-Jul-14    3.17 3.41 8-Jul-14    3.03 3.57 9-Jul-14 Stabilized 1 to 1.4 20 min ON, 40 min OFF 2.60 4.16 10-Jul-14  1 to 1.4 20 min ON, 40 min OFF 2.60 4.16 11-Jul-14  1 to 1.4 20 min ON, 40 min OFF 2.60 4.16 12-Jul-14  1 to 1.4 20 min ON, 40 min OFF 2.60 4.16 13-Jul-14  1 to 1.4 20 min ON, 40 min OFF 2.16 4.99 14-Jul-14  1 to 1.4 20 min ON, 40 min OFF 2.16 4.99 21-Jul-14  1 to 1.4 20 min ON, 40 min OFF 2.16 4.99 23-Jul-14  1 to 1.4 20 min ON, 40 min OFF 2.16 4.99 26-Jul-14  1 to 1.4 20 min ON, 40 min OFF 2.71 3.98 29-Jul-14  1 to 1.4 20 min ON, 40 min OFF 3.61 3.00 30-Jul-14  1 to 1.4 20 min ON, 40 min OFF 3.62 2.92 6-Aug-14  1 to 1.4 20 min ON, 40 min OFF 3.65 2.95 7-Aug-14  1 to 1.4 20 min ON, 40 min OFF 3.46 3.12 8-Aug-14  1 to 1.4 20 min ON, 40 min OFF 3.03 3.57 Appendix C 152  Table C.5: UniBAR-anammox Process Influent (Centrate) Characteristics (Combination 1) Influent Characteristics (Centrate) Date pH DO (mg/L) Temp (C) Alkalinity (mg/L) NH4-N (mg/L) NO2-N (mg/L) NO3-N (mg/L) PO4-P (mg/L) TSS (mg/L) VSS (mg/L) 2-Jan-14 8.18 0.05 15.2 N/A     N/A N/A 3-Jan-14 8.18 0.05 15.5 2924 687.00 0.01 1.07 91.8 170 90 6-Jan-14 8.14 0.09 15.8 2389 745.00 0.02 2.14 99.8 200 140 10-Jan-14 8.13 0.09 17.8 2765 858.00 0.05 0.20 109 400 320 13-Jan-14 8.17 0.09 16.2 2747 895.00 0.07 1.07 116 260 200 15-Jan-14 8.10 0.09 17.6 2535 914.00 0.07 0.08 103 210 180 17-Jan-14 8.11 0.09 18.2 2538 895.00 0.05 0.00 108 170 110 20-Jan-14 8.10 0.10 17.8 2544 771.00 0.10 2.41 99.4 190 170 23-Jan-14 8.10 0.10 17.8 2544 718.00 0.09 3.34 90.3 240 210 27-Jan-14 8.09 0.09 18.4 2862 1030.00 0.25 0.24 131 340 310 3-Feb-14 8.09 0.09 15.3 2485 944.00 14.30 6.60 125 240 200 5-Feb-14 8.12 0.09 16.4 3133 1000.00 7.44 8.06 120 270 210 11-Feb-14 8.11 0.10 17.4 3147 758.00 0.08 0.30 131 270 220 13-Feb-14 8.09 0.08 20.4 2844 893.00 0.08 0.36 147 260 210 18-Feb-14 8.18 0.06 17.0 2626 965.00 0.08 0.30 153 250 190 19-Feb-14 8.15 0.07 17.4 2782 998.00 0.10 0.00 160 190 150 20-Feb-14 8.13 0.09  2726 984.00 0.10 0.00 140 250 180 21-Feb-14 8.15 0.09 17.4 2689 996.00 0.10 0.00 146 280 200 24-Feb-14 8.17 0.07  3157 806.00 0.11 0.39 148 280 220 26-Feb-14 8.15 0.08 17.9 3196 828.00 0.08 0.31 150 260 200 27-Feb-14 8.19 0.05 16.5 3139 851.00 0.08 0.62 150 250 190 28-Feb-14 8.20 0.06 18.0 3220 924.00 0.08 0.22 144 250 190 5-Mar-14 8.19 0.10 17.2 3192 835.27 0.11 0.05 136 230 190 7-Mar-14 8.13 0.09 16.9 3258 884.76 0.19 0.00 154 250 200 10-Mar-14 8.14 0.05 18.0 2942 863.55 0.12 0.05 149 290 260 12-Mar-14 8.18 0.09 19.0 2979 995.86 0.16 0.94 152 230 210 13-Mar-14 7.96 0.07  2989 1001.92 0.19 0.34 150 240 170 Appendix C 153  Influent Characteristics (Centrate) Date pH  DO (mg/L) Temp (C) Alkalinity (mg/L) NH4-N (mg/L) NO2-N (mg/L) NO3-N (mg/L) PO4-P (mg/L) TSS (mg/L) VSS (mg/L) 14-Mar-14 7.99 0.08   3120 997.88 0.15 0.00 154 270 200 19-Mar-14 7.97 0.05   3146 944.35 0.14 0.00 150 230 210 20-Mar-14 7.89 0.06 18.5 3010 990.81 0.14 0.00 158 250 210 21-Mar-14 7.9 0.06 19.6 2923 873.145 0.10 0.06 140.5 230 210 24-Mar-14 7.89 0.09 17.6 2796.1 910.01 0.17 0.13 148 240 190             Table C.6: UniBAR-anammox Process Reactor Characteristics Data with Centrate Feed (Combination 1)  Reactor Characteristics (Centrate Feed) Date pH DO (mg/L) Temp (C) Alkalinity (mg/L) NH4-N (mg/L) NO2-N (mg/L) NO3-N (mg/L) PO4-P (mg/L) TSS (mg/L) VSS (mg/L) 22-Nov-13 6.83 0.10 33.60        11-Dec-13 6.83 0.16 32.70        13-Dec-13 6.99 0.15 34.80 183.10 134.00 0.06 0.53 75.00 2020 1780 14-Dec-13 7.00 0.12 34.90 241.90 69.30 0.06 0.47 65.90 1800 1540 17-Dec-13 6.97 0.11 34.60 217.30 67.20 0.11 1.07 74.70 1920 1680 20-Dec-13 6.89 0.10 34.40 N/A     N/A N/A 23-Dec-13 6.80 0.11 34.50 N/A     N/A N/A 27-Dec-13 6.80 0.09 34.50 216.00 102.00 0.13 3.13 103.00 1920 1720 2-Jan-14 6.89 0.20 33.50 N/A     N/A N/A 3-Jan-14 6.84 0.20 33.40 294.90 185.00 0.15 80.35 113.00 2020 1740 6-Jan-14 6.79 0.18 32.10 201.60 191.00 0.14 112.86 112.00 2300 2020 10-Jan-14 6.84 0.19 32.40 283.30 200.00 0.44 92.96 104.00 2100 1840 13-Jan-14 6.92 0.17 32.70 237.80 194.00 0.31 106.69 119.00 2720 2480 Appendix C 154  UniBAR-anammox Reactor Characteristics (Centrate Feed) Date pH DO (mg/L) Temp (C) Alkalinity (mg/L) NH4-N (mg/L) NO2-N (mg/L) NO3-N (mg/L) PO4-P (mg/L) TSS (mg/L) VSS (mg/L) 15-Jan-14 6.85 0.16 32.50 233.90 204.00 0.25 119.76 117.00 2580 2280 17-Jan-14 6.85 0.17 32.60  209.00 0.19 137.81 118.00 2020 1780 20-Jan-14 7.02 0.17 32.40 354.20 344.00 0.28 139.72 131.00 2720 2580 27-Jan-14 7.01 0.16 32.80 313.70 348.00 0.35 206.65 128.00 2620 2380 3-Feb-14 6.83 0.21 31.90 271.60 375.00 0.43 232.82 139.00 3180 2880 5-Feb-14 6.81 0.19 32.90 246.30 329.00 0.49 204.01 137.00 2580 2320 11-Feb-14 6.79 0.20 33.00 236.00 220.00 0.30 102.40 118.00 3680 2380 13-Feb-14 6.79 0.18 32.90 258.00 362.00 0.30 106.70 147.00 3380 3040 18-Feb-14 6.65 0.15 33.10 160.53 215.00 0.30 120.70 159.00 3580 3180 19-Feb-14 6.63 0.16 32.90 172.46 199.00 0.20 117.80 164.00 3760 3400 20-Feb-14 6.65 0.17 33.00 174.04 199.00 0.20 115.80 167.00 3700 3280 21-Feb-14 6.63 0.15 32.90 220.94 204.00 0.30 114.70 168.00 3500 3140 26-Feb-14 6.65 0.13 33.10 240.17 139.00 0.10 120.90 94.90 3680 3320 27-Feb-14 6.63 0.11 33.00 180.70 199.00 0.20 134.80 148.00 3740 3360 28-Feb-14 6.59 0.12 33.10 160.60 214.00 0.20 139.80 161.00 3700 3340 5-Mar-14 6.51 0.15 33.00 224.90 200.00 0.20 103.70 122.00 4480 4120 7-Mar-14 6.65 0.16 33.00 280.70 243.00 0.30 111.70 167.00 4640 4240 10-Mar-14 6.57 0.17 33.30 227.40 239.00 0.23 109.77 167.00 4700 4280 11-Mar-14 6.70 0.13 33.00 229.90 239.00 0.20 112.81 166.00 4880 4500 12-Mar-14 6.66 0.15 33.20 200.20 224.00 0.15 117.85 167.00 5080 4640 19-Mar-14 6.58  33.40 208.40 240.00 0.34 146.66 168.00 4020 3740 20-Mar-14 6.51  33.20 174.40 231.00 0.32 144.68 167.00 4040 3700 21-Mar-14 6.58  33.40 236.70 221.50 0.33 144.67 166.50 3360 3280 24-Mar-14 6.55  33.10 210.10 220.00 0.29 132.71 165.00 2950 2840 Appendix C 155  Table C.7: UniBAR-anammox Process Effluent Characteristics with Centrate Feed (Combination 1) Effluent Characteristics (Centrate Feed) Date  pH DO (mg/L) Temp (C) Alkalinity (mg/L) NH4-N (mg/L) NO2-N (mg/L) NO3-N (mg/L) PO4-P (mg/L) TSS (mg/L) VSS (mg/L) N-removal (%) P-removal (%) 2-Jan-14    N/A     N/A N/A   3-Jan-14    214.9 145 0.14 82.06 109 1920 1640 78.89 -18.74 6-Jan-14 6.79 0.09 29.1 201.7 184 0.21 118.79 115 2440 2160 75.30 -15.23 10-Jan-14 6.85 0.09 28.8 255.9 184 0.51 104.49 115 2100 1860 78.55 -5.50 13-Jan-14 6.9 0.1 29.3 235.2 177 0.32 110.68 115 2740 2400 80.22 0.86 15-Jan-14 6.85 0.09 26.1 214.8 189 0.24 116.76 119 2480 2220 79.32 -15.53 17-Jan-14 6.96 0.09 19.3  223 0.39 127.61 117 1160 1020 75.08 -8.33 20-Jan-14 6.9 0.09 18 220.1 249 0.47 175.54 128 1040 1000 67.70 -28.77 23-Jan-14    227.7 233 1.91 172.09 112 540 440 67.55 -24.03 27-Jan-14 6.93 0.09 18.4 250 304 0.29 206.71 121 1220 1120 70.49 7.63 3-Feb-14 6.8 0.15 14.2 218.8 294 0.30 212.70 117 1280 1120 68.86 6.40 5-Feb-14 6.8 0.17 16.4 258.1 303 0.72 207.78 128 700 2620 69.70 -6.67 11-Feb-14 6.8 0.16 16.7 275.6 184 0.30 135.10 111 1640 1460 75.73 15.27 13-Feb-14 6.77 0.09 20.2 232.1 230 0.30 134.70 152 1840 1540 74.24 -3.40 18-Feb-14 6.64 0.07 16.4 145.12 215 0.20 129.80 162 1640 1820 77.72 -5.88 20-Feb-14 6.65 0.09 17.6 187.64 202 0.30 109.70 171 1600 1280 79.47 -22.14 21-Feb-14 6.64 0.09 17.8 171.65 201 0.30 112.70 175 1900 1640 79.82 -19.86 24-Feb-14 6.62 0.06 16.9 230.7 198 0.00 123.00 177.3 1520 2080 75.43 -19.80 26-Feb-14 6.66 0.08 16.8 233.4 206 0.20 116.80 149 1760 1300 75.12 0.67 27-Feb-14 6.63 0.07 16.2 184.2 223 0.20 124.80 165 1600 1240 73.80 -10.00 28-Feb-14 6.68 0.1 17 181.1 224 0.20 134.80 164 2100 1880 75.76 -13.89 5-Mar-14 6.53 0.09 16.7 234.8 176 0.23 103.48 126 1980 3400 78.93 7.35 7-Mar-14 6.58 0.06 16.2 277 239 0.44 107.46 167 2500 2980 72.99 -8.44 10-Mar-14 6.62 0.07 18.4 285.2 227 0.32 108.68 163 2800 2480 73.71 -9.40 11-Mar-14 6.78 0.08 18.2 232.8 230 0.23 117.77 163 2780 2520 74.95 -10.14 12-Mar-14 6.71 0.09 18.4 209.1 210 0.25 114.75 156 3100 2780 78.91 -2.63 Appendix C 156  Effluent Characteristics (Centrate Feed) Date  pH DO (mg/L) Temp (C) Alkalinity (mg/L) NH4-N (mg/L) NO2-N (mg/L) NO3-N (mg/L) PO4-P (mg/L) TSS (mg/L) VSS (mg/L) N-removal (%) P-removal (%) 13-Mar-14 6.55 0.09 18.9 239.7 223 0.19 111.81 161 2080 1640 77.74 -7.33 14-Mar-14 6.67 0.09 19.2 219.5 230 0.21 112.79 163 2280 1860 76.95 -5.84 19-Mar-14 6.61  19.7 208.4 233 0.30 120.70 165 2080 1680 75.33 -10.00 20-Mar-14 6.54 0.09 17.6 174.4 229 0.35 132.65 167 1940 1600 76.89 -5.70 21-Mar-14 6.6 0.15 19.7 215.1 242 0.28 123.72 172 1940 1560 72.28 -22.42 24-Mar-14 6.6 0.17 16.7 210.1 228 0.26 102.75 170 2880 2380 74.95 -14.86  Table C.8: UniBAR-anammox Process Influent (Struvite Effluent) Characteristics (Combination 1) Influent Characteristics (Struvite Effluent) Date pH  DO (mg/L) Temp (C) Alkalinity (mg/L) NH4-N (mg/L) NO2-N (mg/L) NO3-N (mg/L) PO4-P (mg/L) TSS (mg/L) VSS (mg/L) 7-Apr-14 8.15 0.08 19 1550 668.90 1.26 0.18 26.69 200 170 8-Apr-14 7.98 0.05   1583 658.30 1.14 1.73 21.50 170 140 9-Apr-14 7.96 0.06 19 1589 658.70 1.14 0.45 14.13 240 210 10-Apr-14 7.88 0.1 19.2 1474 685.50 1.31 0.00 5.13 210 190 11-Apr-14 7.99 0.09 20.5 1452 691.00 1.15 0.20 5.01 210 160 15-Apr-14 8.05 0.05 20 1728 699.50 1.42 0.90 13.83 250 210 16-Apr-14 8.05 0.06 19.5 2016 688.50 1.89 0.66 12.75 220 170 17-Apr-14 7.98 0.09 19.2 1858 679.00 0.71 0.00 6.30 200 180 29-Apr-14 8.01 0.09 19 2532 649.45 0.12 0.91 1.21 240 200 1-May-14 7.99 0.07 19.2 2548 643.40 0.12 1.96 1.73 210 170 5-May-14 7.93 0.08 20 2566 691.38 0.09 0.03 1.13 230 190 Appendix C 157  Influent Characteristics (Struvite Effluent) Date pH DO (mg/L) Temp (C) Alkalinity (mg/L) NH4-N (mg/L) NO2-N (mg/L) NO3-N (mg/L) PO4-P (mg/L) TSS (mg/L) VSS (mg/L) 6-May-14 7.97 0.05 20 2835 646.93 0.15 0.07 8.97 220 200 7-May-14 7.91 0.06 22 2630 682.28 0.14 1.33 76.80 270 240 8-May-14 7.93 0.1 19.3 2828 743.87 0.15 0.17 69.00 280 250 9-May-14 7.91 0.09 19.1 2781 630.24 0.39 1.25 62.40 310 320 14-May-14 7.84 0.05 19.5 3434 632.30 0.13 0.89 13.35 270 310 15-May-14 7.81 0.05 19.9 3392.3 930.56 0.13 0.25 15.74 290 320 16-May-14 7.82 0.04 20.1 3366 970.14 0.13 0.57 15.55 270 280 19-May-14 7.92 0.05 20.5 3239.2 925.60 0.23 0.33 14.68 260 280 20-May-14 7.91 0.05 20.3 3390.3 989.12 0.18 0.06 9.24 270 210 21-May-14 7.82 0.05 20.3 3415.1 972.63 0.14 0.17 12.95 310 270 22-May-14 7.81 0.05 20.4 3449.3 904.96 0.32 0.00 15.11 280 200 24-May-14 7.78 0.09 19.8 3362 678.72 0.37 0.72 15.15 260 170 28-May-14 7.81 0.09 19.6 2820 689.83 0.40 0.19 25.96 250 200 29-May-14 7.81 0.08 19.7 2487 668.73 0.39 0.00 19.33 240 240 30-May-14 7.82 0.05 20.6 2417 646.12 0.32 0.00 11.16 270 180 2-Jun-14 7.71 0.06 20.4 2465 633.28 0.32 0.00 10.92 220 220 3-Jun-14 7.68 0.1 19.8 2566 643.89 0.35 0.00 20.05 210 190 4-Jun-14 7.67 0.09 19.9 2295 685.80 0.28 0.00 27.15 200 160 5-Jun-14 7.79 0.05 20.1 2312 612.07 0.34 0.55 22.23 220 250 7-Jun-14 7.78 0.05 20.5 2229 633.28 0.22 0.05 13.92 250 180 12-Jun-14 7.65 0.06 20.3 2263 635.81 0.39 0.18 9.48 220 230 13-Jun-14 7.68 0.1 20.3 2275 656.51 0.28 0.06 26.64 230 210 16-Jun-14 7.7 0.09 20.4 2342 670.30 0.21 0.13  190 230 18-Jun-14 7.75 0.05 19.8 2375 676.42 0.19 0.18  180 190 20-Jun-14 7.73 0.06 19.6 2362 680.65 0.23 0.25  160 210 Appendix C 158  Influent Characteristics (Struvite Effluent) Date pH DO (mg/L) Temp (C) Alkalinity (mg/L) NH4-N (mg/L) NO2-N (mg/L) NO3-N (mg/L) PO4-P (mg/L) TSS (mg/L) VSS (mg/L) 23-Jun-14 7.69 0.09 19.7 2401.9 690.85 0.15 0.24 97.20 140 190 24-Jun-14 7.75 0.09 20.6 2375.8 675.39 0.21 0.24 107.10 130 200 25-Jun-14 7.77 0.09 20.4 2391.8 627.72 0.16 0.01 110.70 160 180 28-Jun-14 7.82 0.07 20.6 2322 625.43 0.19 0.04  180 200 30-Jun-14 7.81 0.08 20.4 2343 530.74 0.14 0.10  170 220 4-Jul-14 7.89 0.05  2224.8 517.12 0.30 0.05 101.40 160 190 7-Jul-14 7.82 0.06  2201.2 560.55 0.07 0.20 111.90 190 180 8-Jul-14 7.67 0.1 26 2188.8 530.76 0.07 0.39 110.40 160 130 9-Jul-14 7.69 0.09 24.6 2267.7 600.95 0.00 0.15 113.40 180 150 10-Jul-14 7.72 0.05  2196.1 590.85 0.07 0.12 113.50 190 140 11-Jul-14 7.71 0.06 26.2 2251.6 684.79 0.16 0.13 113.70 120 120 12-Jul-14 7.69 0.09 25.4 2480.2 635.30 0.06 0.00 114.90 110 130 13-Jul-14 7.69 0.07 26 2358.4 675.12 0.09 0.00 115.10 110 110 14-Jul-14 7.68 0.08 24.6 2341.5 660.89 0.19 1.10 117.30 110 110 21-Jul-14 7.88 0.05 25.6 2112.5 648.55 0.00 0.20 88.20 130 110 23-Jul-14 7.81 0.06 26.2 2077.4 664.91 0.02 0.60 108.00 140 120 26-Jul-14 7.92 0.1 25.8 2136 687.65 0.05 0.54  150 140 26-Jul-14 7.88 0.09 25.4 2241 692.89 0.09 0.36  190 210 30-Jul-14 7.76 0.08 24.9 2351 685.97 0.06 0.21  210 190 6-Aug-14 7.66 0.05 24.8 2420 595.11 0.00 0.28  220 180 7-Aug-14 7.67 0.06 25.6 2432.8 588.85 0.05 0.25 88.20 220 190 8-Aug-14 7.69 0.1 25.9 2424.6 541.88 0.03 0.45 94.80 230 210 Appendix C 159   Table C.9: UniBAR-anammox Process Reactor Characteristics Data with Struvite Effluent Feed (Combination 1) Reactor Characteristics (Struvite Effluent Feed) Date pH DO (mg/L) Temp (C) Alkalinity (mg/L) NH4-N (mg/L) NO2-N (mg/L) NO3-N (mg/L) PO4-P (mg/L) TSS (mg/L) VSS (mg/L) 7-Apr-14 6.60 0.17 33.00 230.00 220.80 2.27 71.70 145.20 2620 2380 8-Apr-14 6.60 0.15 33.30 212.10 207.00 1.53 75.03 117.30 2440 2400 9-Apr-14 6.58 0.16 33.00 155.40 223.80 1.52 116.48 101.52 3120 2800 10-Apr-14 6.44 0.15 33.00 221.90 499.20 1.60 137.60 73.50 2590 2530 11-Apr-14 6.56 0.12 33.30 250.40 516.00 1.52 183.28 80.70 2200 2660 15-Apr-14 6.57 0.11 33.40 256.20 312.60 2.47 160.13 64.50 2680 2480 16-Apr-14 6.65 0.10 33.30 256.60 239.40 1.61 181.39 67.50 2500 2180 17-Apr-14 6.71 0.11 33.40 159.30 232.80 1.38 155.82 55.92 2740 2560 29-Apr-14 6.71 0.09 33.40 153.60 325.60 0.24 173.01 16.98 3440 3160 1-May-14 6.74 0.20 33.30 190.70 247.50 0.24 190.61 11.97 3140 2920 5-May-14 6.79 0.20 33.30 179.40 218.35 0.36 169.59 5.50 2920 3700 6-May-14 6.80 0.18 33.30 171.10 312.95 0.38 160.22 7.89 2460 3220 7-May-14 6.57 0.19 33.50 161.30 248.05 0.56 178.74 18.12 2380 2180 8-May-14 6.72 0.17 33.50 143.29 337.15 0.54 164.46 26.52 2760 2540 9-May-14 6.56 0.13 32.90 147.90 305.80 0.51 168.34 30.51 2920 2700 14-May-14 6.48 0.11 33.10 142.50 239.25 0.21 190.64 16.98 2520 2300 Appendix C 160  Reactor Characteristics (Struvite Effluent Feed) Date pH DO (mg/L) Temp (C) Alkalinity (mg/L) NH4-N (mg/L) NO2-N (mg/L) NO3-N (mg/L) PO4-P (mg/L) TSS (mg/L) VSS (mg/L) 16-May-14 6.46 0.15 33.00 162.78 245.30 0.22 186.78 15.50 2500 2260 19-May-14 6.44 0.16 32.90 184.08 229.90 0.31 166.34 14.89 2560 2340 20-May-14 6.39 0.17  168.79 224.95 0.36 173.99 12.14 2800 2580 21-May-14 6.66 0.13 33.10 204.40 247.50 0.31 167.44 11.36 2660 1880 22-May-14 6.53 0.12 33.00 163.30 240.35 0.33 170.72 12.20 2420 1680 24-May-14 6.75 0.11 33.10 201.20 216.70 0.67 134.63 14.65 2360 1480 28-May-14 6.82 0.10 33.00 181.20 225.50 0.68 148.37 27.65 2140 1420 29-May-14 6.81 0.11 33.00 173.20 238.15 0.69 154.41 19.10 2020 1860 30-May-14 6.79 0.15 33.30 195.87 234.30 0.69 151.66 16.51 2020 1820 2-Jun-14 6.72 0.12 33.50 189.61 222.20 0.72 137.88 12.74 2180 1920 3-Jun-14 6.77 0.11 33.50 195.82 206.80 0.67 125.28 19.71 1960 1720 4-Jun-14 6.84 0.10 32.90 143.17 204.60 0.75 106.72 23.59 2000 1780 5-Jun-14 6.91 0.11 33.10 162.66 209.55 0.24 92.57 22.25 1960 1820 7-Jun-14 6.87 0.09 33.40 144.34 213.40 0.32 112.47 20.50 2500 2300 12-Jun-14 6.63 0.15 33.40 151.41 248.05 70.38 124.47 34.48 1660 1500 13-Jun-14 6.86 0.52 33.30 248.81 242.00 110.29 157.11 40.86 1540 1440 16-Jun-14 6.61 0.17 33.50 160.63 224.36 0.78 114.40  2500 2020 18-Jun-14 6.58 0.14 32.90 162.42 194.13 0.93 116.70  2340 1840 20-Jun-14 6.45 0.15 33.10 154.36 185.40 1.52 121.31  2410 1920 Appendix C 161  Reactor Characteristics (Struvite Effluent Feed) Date pH DO (mg/L) Temp (C) Alkalinity (mg/L) NH4-N (mg/L) NO2-N (mg/L) NO3-N (mg/L) PO4-P (mg/L) TSS (mg/L) VSS (mg/L) 23-Jun-14 6.64 0.17 32.90 166.94 177.10 2.35 113.15 100.20 2580 1760 24-Jun-14 6.58 0.16 33.00 144.84 177.10 2.04 126.12 103.20 2180 1500 25-Jun-14 6.71 0.18 32.90 173.31 217.80 7.35 120.20 104.70 2080 1660 30-Jun-14 6.60 0.12 33.10 206.20 156.47 0.24 105.56  2140 2060 4-Jul-14 6.54 0.13 33.00 204.30 142.45 0.28 116.41 111.90 2080 1920 7-Jul-14 6.54 0.15 33.10 191.83 177.65 0.44 124.41 117.90 2040 1707 8-Jul-14 6.58 0.14 33.00 163.85 161.70 0.24 124.06 112.80 2580 2400 9-Jul-14 6.42 0.18 33.00 219.92 177.65 0.27 127.88 119.40 2080 1980 10-Jul-14 6.44 0.17 33.30 210.40 179.13 0.19 129.42 120.10 2160 1830 11-Jul-14 6.41 0.10 33.50 200.66 184.80 0.17 131.83 122.40 2540 2260 12-Jul-14 6.42 0.11 33.50 173.97 189.20 0.17 141.73 122.10 2380 2100 13-Jul-14 6.43 0.15 34.90 206.45 192.47 0.18 145.38 122.40 2410 2180 14-Jul-14 6.41 0.15 34.60 199.96 199.83 0.22 152.68 123.60 2480 2260 21-Jul-14 6.58 0.16 34.40 189.71 198.00 0.18 141.35 118.50 2200 2100 23-Jul-14 6.65 0.17 34.50 167.29 206.25 0.20 162.25 124.20 2180 2000 30-Jul-14 6.63 0.14 33.40 185.30  0.23 153.85  2060 1760 6-Aug-14 6.56 0.13 32.10 179.99  0.14 145.12  2450 2040 7-Aug-14 6.51 0.14 32.40 194.69 150.15 0.28 155.58 122.40 2280 1820 8-Aug-14 6.57 0.14 33.50 189.47 122.10 0.10 163.64 121.80 2450 2000  Appendix C 162  Table C.10: UniBAR-anammox Process Effluent Characteristics with Struvite Effluent Feed (Combination 1) Effluent Characteristics (Struvite Effluent Feed) Date pH DO (mg/L) Temp (C) Alkalinity (mg/L) NH4-N (mg/L) NO2-N (mg/L) NO3-N (mg/L) PO4-P (mg/L) TSS (mg/L) VSS (mg/L) N-removal (%) P-removal (%) 7-Apr-14 6.62 0.09 19 252.30 231.00 2.40 64.80 154.20 1580 2020 65.47 -47.20 8-Apr-14 6.65 0.09 19.2 223.80 213.00 0.94 80.40 147.60 1520 1340 67.64 -58.21 9-Apr-14 6.52 0.09 19.1 177.00 219.00 1.54 163.06 121.80 1480 1360 66.75 -76.84 10-Apr-14 6.54  20 222.70 221.60 1.51 189.89 93.60 1960 1760 67.67 -17.25 11-Apr-14 6.59 0.09 19.5 259.80 226.80 1.48 193.52 85.50 1460 1680 67.18 -16.07 15-Apr-14 6.6 0.15 19 260.50 185.40 1.47 155.73 59.70 1620 1380 73.50 -3.31 16-Apr-14 6.6 0.17 19 257.10 225.00 1.42 168.38 70.50 2260 1200 67.32 -4.53 17-Apr-14 6.75 0.09 19.2 155.60 204.00 1.39 158.81 61.80 1240 1780 69.96 -8.80 29-Apr-14 6.75 0.1 19.2 152.10 182.70 0.26 199.39 21.81 1400 1300 71.87 -1.59 1-May-14 6.7 0.09 19.1 177.60 212.80 0.97 209.13 14.01 1980 1860 66.93 -7.07 5-May-14 6.73 0.09 19.1 168.70 216.70 0.41 178.34 8.19 1200 1580 68.66 -6.26 6-May-14 6.73 0.09 19 141.90 247.50 0.50 199.15 6.45 1440 2240 61.74 2.80 7-May-14 6.59  19 159.70 243.65 0.48 199.72 17.55 1420 1240 64.29 7.70 8-May-14 6.66 0.09 19.5 141.30 249.15 1.00 185.45 23.22 1860 1740 66.51 6.60 9-May-14 6.65 0.15 19.3 140.10 245.85 0.78 171.37 27.09 1620 1560 60.99 5.60 14-May-14 6.51 0.17 19.1 140.50 244.20 0.47 196.98 15.21 2360 1200 61.38 -13.92 15-May-14 6.55 0.16 20 166.50 251.35 0.27 202.68 14.85 1880 1780 72.99 5.63 16-May-14 6.62 0.09 19.5 161.50 247.50 0.28 193.87 15.42 1920 1860 74.49 0.84 19-May-14 6.59 0.07 19 201.13 225.50 0.37 170.68 16.96 2300 1400 75.64 -15.55 20-May-14 6.6 0.08 19 190.43 234.30 0.42 168.43 14.11 1680 1540 76.31 -52.72 21-May-14 6.67 0.09 19.2 187.45 207.35 0.74 138.96 13.74 1820 1560 78.68 -6.09 Appendix C 163  Effluent Characteristics (Struvite Effluent Feed) Date pH DO (mg/L) Temp (C) Alkalinity (mg/L) NH4-N (mg/L) NO2-N (mg/L) NO3-N (mg/L) PO4-P (mg/L) TSS (mg/L) VSS (mg/L) N-removal (%) P-removal (%) 22-May-14 6.76 0.09 19.2 227.18 244.20 0.32 171.83 12.97 1640 1460 73.02 14.17 24-May-14 6.74 0.06 20.1 232.40 196.90 0.63 128.62 15.01 1920 1160 70.99 0.92 28-May-14 6.8 0.08 19.1 225.50 219.45 0.65 130.25 26.09 1720 1200 68.19 -0.50 29-May-14 6.67 0.07 19.5 169.20 243.65 0.69 142.31 18.87 1160 1420 63.56 2.37 30-May-14 6.76 0.1 19 192.84 214.50 0.68 126.92 16.82 1300 1160 66.80 -50.71 2-Jun-14 6.78 0.09 19.5 202.23 200.75 0.62 121.48 13.42 1720 1420 68.30 -22.87 3-Jun-14 6.8 0.09 19.3 219.16 204.05 0.71 120.31 19.87 1460 1380 68.31 0.89 4-Jun-14 6.82 0.1 20.5 151.61 194.15 1.07 100.72 25.64 1560 1480 71.69 5.56 5-Jun-14 6.91 0.09 20.4 156.59 215.60 0.50 102.72 21.50 1480 1400 64.78 3.28 7-Jun-14 6.79 0.09 20.2 152.08 206.80 0.68 121.56 19.80 1520 1400 67.34 -42.24 12-Jun-14 6.68 0.09 19.9 153.14 231.55 30.51 119.94 32.47 1320 1220 63.58 -24.36 13-Jun-14 6.82   241.20 301.35 42.27 142.73 39.15 1000 1600 54.10 -46.96 16-Jun-14 6.62 0.09 19 156.87 240.50 0.51 110.85  2140 1240   18-Jun-14 6.6 0.15 19.2 163.70 215.94 0.35 112.74  1860 1130   20-Jun-14 6.58 0.17 19.2 158.43 205.74 0.64 115.26  1450 1200   23-Jun-14 6.62 0.16 19.1 141.73 170.50 0.19 46.73 99.00 1640 1040 75.32 -1.85 24-Jun-14 6.57 0.09 19.1 209.20 191.40 0.18 85.95 105.90 1980 1160 71.66 1.12 25-Jun-14 6.66 0.07 19 159.20 205.70 2.41 86.86 108.90 1160 1020 67.23 1.63 28-Jun-14 6.88 0.08 19 290.11 320.61 32.10 138.78  1100 800   30-Jun-14 6.63 0.09  210.13 154.74 0.51 101.75  1540 1240   4-Jul-14 6.69 0.09 19.5 206.41 142.45 0.61 114.97 114.90 1480 1140 72.45 -13.31 7-Jul-14 6.67 0.06 19 197.87 163.35 0.66 114.29 121.50 1800 1540 70.86 -8.58 8-Jul-14 6.59 0.08 19.5 256.52 166.10 0.20 104.02 121.20 1320 2060 68.70 -9.78 9-Jul-14 6.61 0.07 19.3 218.92 166.10 0.19 113.11 117.30 1940 1740 72.36 -3.44 Appendix C 164  Effluent Characteristics (Struvite Effluent Feed) Date pH DO (mg/L) Temp (C) Alkalinity (mg/L) NH4-N (mg/L) NO2-N (mg/L) NO3-N (mg/L) PO4-P (mg/L) TSS (mg/L) VSS (mg/L) N-removal (%) P-removal (%) 10-Jul-14 6.42 0.1 20.5 264.20 168.65 0.19 120.74 120.20 1630 1440 71.46 -5.90 11-Jul-14 6.69 0.09 20.4 209.50 174.35 0.21 129.04 122.10 1420 1240 74.54 -7.39 12-Jul-14 6.52 0.08 20.2 204.46 184.25 0.28 138.32 123.30 1660 1920 71.00 -7.31 13-Jul-14 6.53 0.09 19.9 206.70 185.10 0.34 140.14 122.60 1280 1120 72.58 -6.52 14-Jul-14 6.59 0.09 20.2 208.60 188.10 0.39 144.81 123.60 1540 1400 71.54 -5.37 21-Jul-14 6.51 0.06 19.9 174.94 167.75 0.30 134.75 108.30 1440 1160 74.13 -22.79 23-Jul-14 6.7 0.08 19.1 181.75 196.35 0.24 160.06 125.40 1700 1600 70.47 -16.11 26-Jul-14 6.58 0.07 19 168.70 184.74 0.21 148.63  1640 1450   26-Jul-14 6.62 0.1 19 158.20 171.84 0.19 139.72  1820 1340   30-Jul-14 6.6 0.09 19.3 196.46 162.68 0.42 145.55  1670 1240   6-Aug-14 6.6 0.09 20.5 152.43 158.75 0.26 131.22  2130 1580   7-Aug-14 6.5 0.1 20.4 191.32 142.45 0.26 144.36 123.00 1900 1280 75.81 -39.46 8-Aug-14 6.68 0.09  163.21 123.85 0.54 161.63 121.50 2080 1280 77.14 -28.16     Appendix C 165  Table C.11: Mg concentration in combination 1 Mg Concentration in Combination 1 Background Study with Centrate Feed to Both Reactors Combined Process (Combination 1) Date Influent (Centrate) Anammox Reactor Anammox Effluent Struvite Effluent Date Influent (Centrate) Anammox Influent (Struvite Effluent) Anammox Reactor Anammox Effluent 13-Feb-14 0.69 1.31 1.97 39.77 29-Apr-14 0.39 127.66 72.90 65.75 18-Feb-14 0.53 1.28 1.49 23.72 1-May-14 0.43 111.09 97.91 91.53 19-Feb-14 0.26 1.26 1.76 45.76 5-May-14 0.36 114.40 100.66 97.66 20-Feb-14 0.59 1.37 1.47 48.06 6-May-14 0.69 119.31 104.17 107.04 21-Feb-14 0.31 1.40 1.40 69.16 7-May-14 0.41 121.30 92.71 97.39 24-Feb-14 0.38 1.36 1.45 27.55 8-May-14 0.44 40.15 54.61 88.72 26-Feb-14 0.41 1.22 1.80 31.19 9-May-14 0.31 55.54 57.16 76.72 27-Feb-14 0.43 1.13 1.42 33.47 14-May-14 0.33 40.22 34.05 37.35 28-Feb-14 0.88 0.91 6.20 59.50 15-May-14 0.68 44.17 39.50 35.36 5-Mar-14 0.59 1.27 3.64 54.55 16-May-14 0.79 35.22 35.85 38.47 7-Mar-14 0.85 1.29 1.38 45.00 19-May-14 0.82 34.44 32.14 36.30 10-Mar-14 0.79 1.30 1.29 35.00 20-May-14 0.69 30.72 30.43 35.09 11-Mar-14 0.53 1.21 1.61 21.40 21-May-14 0.60 30.40 28.81 27.60 12-Mar-14 0.62 1.20 1.33 22.50 22-May-14 0.52 35.93 28.97 34.04 13-Mar-14 0.46 2.36 1.25 22.59 25-Jun-14 0.56 51.35 49.25 48.47 14-Mar-14 0.91 1.31 1.16 25.64 28-Jun-14 0.71 50.45 52.11 45.16 19-Mar-14 1.07 1.23 1.45 28.60 30-Jun-14 0.97 45.62 46.41 44.22 20-Mar-14 0.82 1.16 2.80 31.64 4-Jul-14 0.88 44.85 42.74 40.98 21-Mar-14 0.83 0.97 1.00 33.00 7-Jul-14 0.81 48.41 45.69 40.34 24-Mar-14 0.81 1.00 1.50 38.65 8-Jul-14 0.85 47.23 46.17 39.88 Appendix C 166  Table C.12: UniBAR-anammox Process Operating Condition Data with Centrate Feed (Combination 2) Operating Conditions of UniBAR-anammox Process Date Remarks Air Flow Rate (LPM) Air pump Timer Feed consumption rate (L/d) HRT (d) 13-Feb-14 Start up 0.5 10 min ON/4 h OFF   18-Feb-14  10 1 min ON/1 h OFF 86.68 20.96 26-Feb-14  10 1 min ON/2 h OFF 62.40 29.12 28-Feb-14  20 1 min ON/2 h OFF 67.13 27.06 5-Mar-14    67.87 26.77 19-Mar-14  25 5 min ON/2 h OFF 87.87 20.68 20-Mar-14    87.87 20.68 21-Mar-14  25 15 min ON/2 h OFF 114.85 15.82 7-Apr-14    117.69 15.44 8-Apr-14    97.87 18.56 11-Apr-14  25 30 min ON/2 h OFF 211.15 8.60 15-Apr-14    196.71 9.24 22-Apr-14    150.00 12.11 1-May-14    123.36 14.73 6-May-14  25 20 min ON/1 h OFF 225.05 8.07 9-May-14    111.00 16.37 20-May-14    116.69 15.57 24-May-14    116.69 15.57 26-May-14    100.02 18.16 Appendix C 167  Operating Conditions of UniBAR-anammox Process Date Remarks Air Flow Rate (LPM) Air pump Timer Feed consumption rate (L/d) HRT (d) 27-May-14  10 40 min ON/4 h OFF 116.69 15.57 28-May-14    66.68 27.25 30-May-14    66.68 27.25 2-Jun-14    75.02 24.22 10-Jun-14    66.63 27.27 16-Jun-14    72.24 25.15 18-Jun-14  22 40 min ON/2 h OFF 104.19 17.44 19-Jun-14    116.69 15.57 23-Jun-14  25 15 min ON/40 min OFF 133.36 13.62 24-Jun-14    100.02 18.16 25-Jun-14   25 min ON/40 min OFF 191.71 9.48 27-Jun-14    139.61 13.01 30-Jun-14    170.87 10.63 1-Jul-14  25 30 min ON/30 min OFF 125.03 14.53 4-Jul-14    212.54 8.55 7-Jul-14    279.22 6.51 8-Jul-14    262.55 6.92 9-Jul-14    241.72 7.52 11-Jul-14    237.55 7.65 12-Jul-14    216.71 8.38 14-Jul-14    262.55 6.92 Appendix C 168  Operating Conditions of UniBAR-anammox Process Date Remarks Air Flow Rate (LPM) Air pump Timer Feed consumption rate (L/d) HRT (d) 17-Jul-14    245.88 7.39 21-Jul-14  35 40 min ON/20 min Off 308.40 5.89 23-Jul-14    355.63 5.11 24-Jul-14    355.63 5.11 25-Jul-14    266.72 6.81 6-Aug-14    327.84 5.54 7-Aug-14    283.39 6.41 8-Aug-14    333.40 5.45 12-Aug-14    337.57 5.38 14-Aug-14    337.57 5.38 19-Aug-14    283.39 6.41 26-Aug-14    244.49 7.43 27-Aug-14    230.05 7.90 28-Aug-14    233.38 7.78 29-Aug-14    233.38 7.78 30-Aug-14    233.38 7.78 2-Sep-14    295.89 6.14 3-Sep-14    233.38 7.78 4-Sep-14 Diluted centrate feed 10 40 min ON/20 min OFF 133.36 13.62 5-Sep-14 air back to 35 LPM 35 40 min ON/20 min OFF 133.36 13.62 9-Sep-14 Diluted centrate feed 10 20 min ON/20 min OFF 116.69 15.57 Appendix C 169  Operating Conditions of UniBAR-anammox Process Date Remarks Air Flow Rate (LPM) Air pump Timer Feed consumption rate (L/d) HRT (d) 11-Sep-14    183.37 9.91 12-Sep-14    175.04 10.38 16-Sep-14 air back to 35 LPM 35 40 min ON/20 min OFF 533.44 3.41 17-Sep-14    266.72 6.81 18-Sep-14    316.73 5.74 19-Sep-14    266.72 6.81 20-Sep-14    260.05 6.99 21-Sep-14    316.73 5.74 23-Sep-14    266.72 6.81 24-Sep-14    260.05 6.99 25-Sep-14    266.70 6.81 28-Sep-14    285.61 6.36 29-Sep-14    310.06 5.86 5-Oct-14    315.45 5.76 6-Oct-14    310.12 5.86 7-Oct-14    325.07 5.59 8-Oct-14    325.04 5.59 9-Oct-14    350.07 5.19 17-Oct-14    216.71 8.38 18-Oct-14    350.07 5.19 19-Oct-14    322.29 5.64 Appendix C 170  Operating Conditions of UniBAR-anammox Process Date Remarks Air Flow Rate (LPM) Air pump Timer Feed consumption rate (L/d) HRT (d) 20-Oct-14    320.06 5.68 31-Oct-14  35 40 min On/2h OFF 383.41 4.74 1-Nov-14    116.69 15.57 5-Nov-14    98.98 18.36 7-Nov-14      8-Nov-14    77.79 23.35 9-Nov-14    85.12 21.34 10-Nov-14    125.03 14.53 12-Nov-14    116.69 15.57 14-Nov-14    133.36 13.62 18-Nov-14    83.35 21.80 21-Nov-14   20 min ON/4h OFF   26-Nov-14    50.01 36.33 28-Nov-14    50.01 36.33 1-Dec-14    37.51 48.44 5-Dec-14    50.01 36.33 8-Dec-14    52.79 34.42 10-Dec-14    50.14 36.23 11-Dec-14    47.23 38.47 13-Dec-14    43.34 41.92 14-Dec-14    40.01 45.41 Appendix C 171  Table C.13: UniBAR-anammox Process Influent (Centrate) Characteristics (Combination 2) Influent (Centrate) Characteristics Date pH DO (mg/L) Temp (C) Alkalinity (mg/L) NH4-N (mg/L) NO2-N (mg/L) NO3-N (mg/L) PO4-P (mg/L) TSS (mg/L) VSS (mg/L) 13-Feb-14 8.15 0.05 15.2 N/A N/A N/A N/A N/A N/A N/A 19-Mar-14 8.11 0.07 17.60 3004.00 632.26 0.80 4.94 126.00 190 180 20-Mar-14 8.04 0.06 17.40 3093.00 774.17 0.21 0.00 122.00 190 150 21-Mar-14 8.07 0.05 16.90 3063.00 727.20 0.17 1.32 117.00 230 170 7-Apr-14 8.10 0.06 16.50 1861.00 431.50 0.61 0.00 68.40 140 160 1-May-14     451.47 1.46 10.39 76.07 230 200 6-May-14 8.11 0.05 20.80  642.87 0.14 3.07 101.42 240 210 9-May-14 8.02  20.50  763.06 0.17 10.57 113.85 210 180 20-May-14 8.12 0.05 19.90 3653.00 895.87 0.50 0.00 121.90 240 280 24-May-14 8.06 0.05 19.80 3952.40 972.63 0.58 0.00 125.60 310 250 26-May-14 8.04 0.06 20.30 3683.00 759.02 0.54 0.00 124.20 300 190 24-Jun-14 7.70 0.09 20.40 2924.00 634.79 0.15 0.00 110.70 190 210 25-Jun-14 7.73 0.09 20.60 3029.00 785.28 0.27 0.09 130.20 210 200 27-Jun-14 7.69 0.09 21.10 2966.00 789.32 0.30 0.02 131.10 220 190 1-Jul-14 7.93 0.10 25.40 3737.80 1005.15 0.22 0.12 153.00 400 290 4-Jul-14 7.92 0.10 26.50 3620.20 1019.60 0.31 0.00 158.10 280 240 7-Jul-14 7.88 0.09 26.10 3597.50 955.46 0.19 0.09 157.80 280 240 8-Jul-14 7.86 0.09 25.90 3613.60 996.87 0.07 0.41 150.40 240 220 9-Jul-14 7.86 0.09 25.40 3673.50 624.18 0.45 0.68 130.20 420 350 11-Jul-14 7.86 0.10 25.60 3750.60 917.59 0.24 0.89 162.90 350 280 12-Jul-14 7.85  25.30 3712.10 989.30 0.10 0.29 165.60 330 270 Appendix C 172  Influent (Centrate) Characteristics Date pH DO (mg/L) Temp (C) Alkalinity (mg/L) NH4-N (mg/L) NO2-N (mg/L) NO3-N (mg/L) PO4-P (mg/L) TSS (mg/L) VSS (mg/L) 14-Jul-14 7.81 0.05 25.70 3757.50 1001.42 0.19 0.16 168.60 350 290 17-Jul-14 7.87 0.04 26.40 3314.20 858.50 0.25 0.09 151.20 260 200 21-Jul-14 7.84 0.05 26.50 2825.60 728.21 0.15 0.04 148.70 200 150 23-Jul-14 7.85 0.04 26.10 2771.60 641.35 0.11 0.11 144.40 260 220 24-Jul-14 8.01 0.05 26.20 2797.00 368.65 0.00 0.17 90.60 240 160 25-Jul-14 8.00 0.05 27.10 2635.60 468.64 0.00 0.21 110.10 300 220 6-Aug-14 7.90 0.05 28.10 2621.10 459.55 0.00 0.01 117.90 170 150 7-Aug-14 7.83 0.05 27.80 2632.00 481.77 0.00 0.24 102.30 200 180 8-Aug-14 7.87 0.09 25.40 2658.60 482.78 0.00 0.45 109.20 150 160 12-Aug-14 7.90 0.07 25.40 2477.10 486.32 0.00 0.12 110.40 200 170 14-Aug-14 8.00 0.09 24.60 3002.30 503.99 0.00 0.12 107.60 360 340 19-Aug-14 7.95 0.09 24.50 2984.50 565.10 0.00 0.09 123.60 270 240 26-Aug-14 7.77 0.07 23.50 3359.20 774.67 0.27 0.06 131.45 220 190 27-Aug-14 7.80 0.08  3214.20 919.10 0.18 0.00 131.40 320 260 28-Aug-14 7.79 0.05 22.40 3411.60 925.70 0.16 0.14 114.70 310 250 29-Aug-14 7.77 0.06 20.90 3143.50 913.60 0.13 0.21 118.14 280 260 30-Aug-14 7.80 0.10 20.40 3169.78 925.73 0.13 0.29 122.82 300 280 2-Sep-14 7.82 0.09 21.50 3313.00 934.25 0.16 0.33 127.50 290 250 3-Sep-14 7.82 0.05 21.50 3279.40 731.25 0.11 0.24 123.90 310 240 4-Sep-14 7.82 0.06  3348.50 798.41 0.13 0.20 126.30 240 200 16-Sep-14 7.97 0.09 22.50 2927.30 653.49 1.89 0.00 125.60 260 220 17-Sep-14 8.05 0.07 22.30 3197.36 658.52 2.15 0.00 124.40 230 200 18-Sep-14 8.02  21.70 3226.45 671.94 2.10 0.00 126.30 260 220 19-Sep-14 7.98 0.08 22.50 3120.19 664.10 1.95 0.00 121.90 160 160 20-Sep-14 7.99 0.05  2910.00 658.52 2.14 0.00 130.20 180 150 Appendix C 173  Influent (Centrate) Characteristics Date pH DO (mg/L) Temp (C) Alkalinity (mg/L) NH4-N (mg/L) NO2-N (mg/L) NO3-N (mg/L) PO4-P (mg/L) TSS (mg/L) VSS (mg/L) 21-Sep-14 8.01 0.06 22.10 3060.00 673.60 1.89 0.00 129.71 210 180 23-Sep-14 7.98 0.06 21.80 3100.00 543.89 0.86 0.12 127.50 220 170 24-Sep-14 7.99 0.09 21.60 3220.00 596.22 0.82 0.24 128.70 250 190 25-Sep-14 7.95   3040.00 586.80 0.64 0.21 128.10 230 180 28-Sep-14 7.94 0.06 20.40 3133.00 662.40 0.38 0.27 129.10 220 200 29-Sep-14 7.96 0.06 19.50 3184.10 675.69 0.21 0.35 128.90 210 180 5-Oct-14 8.05 0.09 19.40 3040.00 664.12 0.77 0.12 120.60 190 160 6-Oct-14 8.10  17.20 3150.00 652.89 0.82 0.08 113.80 200 180 7-Oct-14 8.04  17.10 3257.90 635.29 0.86 0.00 112.50 180 170 8-Oct-14 7.97 0.08 16.80 3386.20 678.22 0.86 0.10 114.30 120 160 9-Oct-14 7.98 0.05 16.80 3201.00 709.53 0.82 0.00 115.50 180 160 19-Nov-14 8.02   3521.00 688.32 2.26 -1.25 141.30 300 260 10-Dec-14 8.04   3787.80 682.26 0.56 -0.44 110.40 230 170 11-Dec-14 7.98   3754.20 833.76 0.53 -0.41 125.10 200 160 13-Dec-14 7.95   3713.90 882.74 2.52 -2.50 126.60 240 190 14-Dec-14 7.96   3697.80 837.80 0.65 -0.34 124.20 180 160  Table C.14: UniBAR-anammox Process Reactor Characteristics with Centrate Feed (Combination 2) Reactor Characteristics with Centrate Feed Date pH DO (mg/L) Temp (C) Alkalinity (mg/L) NH4-N (mg/L) NO2-N (mg/L) NO3-N (mg/L) PO4-P (mg/L) TSS (mg/L) VSS (mg/L) 13-Feb-14   27  49.55      18-Feb-14 8.03 7.58  701.63 210 1.65 10.53 97.6 320 280 5-Mar-14  7.76 33.4 458.48 164.10 3.12 10.50 90.06 450 310 19-Mar-14 7.03 7.69 32.3 154.82 86.14 1.41 31.11 95.58 820 560 Appendix C 174  Reactor Characteristics with Centrate Feed Date pH DO (mg/L) Temp (C) Alkalinity (mg/L) NH4-N (mg/L) NO2-N (mg/L) NO3-N (mg/L) PO4-P (mg/L) TSS (mg/L) VSS (mg/L) 20-Mar-14    68.94 72.26 1.16 42.25 96.54 860 540 21-Mar-14   33.6 384.16 130.70 1.11 38.01 98.94 840 510 7-Apr-14 7.01 0.15 33.6 353.11 126.10 1.40 24.74 105.36 1720 1120 8-Apr-14 6.61 0.16 33.30  105.66 0.33 37.68 53.55 1840 1240 11-Apr-14 6.56 0.15 33.40  100.87 0.25 35.72 53.01 1180 1080 15-Apr-14 6.6 0.12 33.30  108.30 0.25 46.83 49.98 1620 1500 22-Apr-14 6.7 0.11 33.40  102.69 0.24 65.32 46.44 1890 1750 1-May-14 6.65 0.10 33.40  117.70 0.52 88.14 45.81 1900 1740 6-May-14 6.62 0.11 33.30  111.10 0.26 86.09 43.14 1020 940 9-May-14 6.48 0.09 33.30  147.95 0.30 79.29 46.59 960 910 20-May-14 6.41 0.20 33.30 161.62 102.19 0.61 54.22 110.3 1440 740 24-May-14 6.3 0.20 33.50 144.65 128.70 0.60 82.40 119.1 1300 680 26-May-14 6.56 0.18 33.50 160.33 143.55 0.72 101.53 127.8 1780 980 24-Jun-14 6.37 0.20  143.6 104.61 0.21 63.21 120 2240 1940 25-Jun-14 6.4 0.18 33.10 185.4 139.15 0.30 87.20 113.7 2520 2240 27-Jun-14 6.4 0.15 32.90 186.5 159.50 0.09 103.15 132 2100 1840 1-Jul-14 6.35 0.17  161.05 198.55 0.24 138.91 132.9 1740 1580 4-Jul-14 6.41   160.31 261.80 0.24 212.06 134.7 2360 2080 7-Jul-14 6.55 0.19 32.90 197.91 303.05 0.30 241.70 144.3 2300 2020 8-Jul-14 6.65 0.17 33.10 224.4 316.07 0.40 249.30 146.6 2240 1940 9-Jul-14 6.59 0.16 32.90 242.43 293.15 0.31 243.89 131.7 2180 1920 11-Jul-14 6.58 0.17 33.00 219.06 352.00 0.25 270.90 154.8 2380 2100 12-Jul-14 6.67 0.17 32.90 256.29 343.20 0.43 261.92 154.8 2080 1840 14-Jul-14 6.64   230.8 329.45 0.49 254.71 155.4 1780 1580 17-Jul-14 6.59 0.16 32.90 224.54 299.20 0.42 236.63 157.5 1880 1700 21-Jul-14 6.57 0.21 33.10 235.96 275.00 0.46 213.49 152.4 1760 1640 23-Jul-14 6.55 0.19 32.90 190.1 237.23 0.39 177.08 144.6 2020 1780 24-Jul-14 6.4   181.27 168.30 0.00 125.95 118.5 1110 1190 25-Jul-14 6.43   192.85 193.60 0.00 145.75 137.7 1190 1040 Appendix C 175  Reactor Characteristics with Centrate Feed Date pH DO (mg/L) Temp (C) Alkalinity (mg/L) NH4-N (mg/L) NO2-N (mg/L) NO3-N (mg/L) PO4-P (mg/L) TSS (mg/L) VSS (mg/L) 6-Aug-14 6.47 0.16  183.56 159.50 0.00 111.10 127.5 2560 2170 7-Aug-14 6.48  33.10 196.59 143.55 0.03 90.39 120.9 3230 2720 8-Aug-14 6.51 0.12 33.00 202.68 128.15 0.08 77.47 109.8 2450 2200 12-Aug-14 6.5 0.15 32.90 128.7 126.50 0.01 85.63 117 2460 2220 14-Aug-14 6.53 0.16 33.10 168.7 134.57 0.11 86.90 119 2440 2160 19-Aug-14 6.52 0.17 33.40 161.6 140.25 0.14 96.33 124.2 3180 2640 26-Aug-14 6.45 0.13 33.40 170.8 182.60 0.41 154.70 130.7 2720 2500 27-Aug-14 6.38 0.15 33.30 178.9 162.25 0.24 146.36 110.7 2760 2520 28-Aug-14 6.36 0.16 33.50 168.69 154.71 0.34 138.46 113.87 2640 2420 29-Aug-14 6.39 0.17 32.90 161.84 153.21 0.26 149.14 117.14 2810 2610 30-Aug-14 6.42 0.15 33.10 173.64 178.10 0.30 164.79 123.4 2540 2460 2-Sep-14 6.21   129.22 220.00 0.33 179.52 126.3 2300 1980 3-Sep-14 6.24 0.16 33.00 139.76 196.35 0.29 182.14 120.3 2120 2000 4-Sep-14 6.4 0.17 32.90 142.07 238.15 0.27 187.62 115.5 2260 2020 16-Sep-14 6.56  33.00 157.34 237.60 2.01 227.94 110.8 4680 4200 17-Sep-14 6.58  32.90 206.217 325.60 1.96 264.24 115.2 4240 3820 18-Sep-14 6.55   214.423 324.16 2.01 265.14 114.46 3780 3420 19-Sep-14 6.6   212.439 328.63 1.97 261.27 117.6 4120 3700 20-Sep-14 6.54   190.5 353.65 1.97 302.73 120.3 3960 3540 21-Sep-14 6.53 0.15 33.00 215.4 345.22 2.14 284.65 125.97 4080 3610 23-Sep-14 6.58 0.12 33.00 210.56 293.15 0.75 264.20 124.68 3850 3130 24-Sep-14 6.64 0.11 33.30 184.25 310.56 0.81 254.10 123.9 3540 2980 25-Sep-14 6.62 0.10 33.50 198.11 345.60 0.56 248.60 122.48 3360 2840 28-Sep-14 6.9 0.11 33.50 184.63 350.42 0.46 231.64 123.4 3420 2820 29-Sep-14 6.8 0.09 34.90 208.54 369.05 0.73 271.52 124.8 3880 3060 5-Oct-14 6.8 0.20 34.60 240.6 271.65 0.72 230.10 119.5 3630 2950 6-Oct-14 6.75 0.20  212.84 283.70 0.82 211.60 113.4 3450 2740 7-Oct-14 6.68 0.18 33.50 257.9 235.95 0.94 185.51 112.6 3120 2600 8-Oct-14 6.6 0.19 34.90 238.61 244.75 0.92 209.18 115.5 3370 2920 Appendix C 176  Reactor Characteristics with Centrate Feed Date pH DO (mg/L) Temp (C) Alkalinity (mg/L) NH4-N (mg/L) NO2-N (mg/L) NO3-N (mg/L) PO4-P (mg/L) TSS (mg/L) VSS (mg/L) 9-Oct-14 6.72 0.17 34.60 241.81 262.35 0.87 207.03 113.7 3480 2680 14-Nov-14 6.56 0.13 32.90 142.43 202.4 2.1835 165.5665 97.5 3420 3060 19-Nov-14 6.58 0.11 33 162.03 190.3 2.2825 128.6175 104.1 8880 8000 10-Dec-14 6.55 0.12 33.2 119.78 116.6 1.9041 73.6659 114.9 2020 1840 11-Dec-14 6.6 0.15 32.8 195.23 136.4 1.01035 96.99965 125.7 500 420 13-Dec-14 6.54   325.39 196.35 6.919 95.106 126.9 1620 1460 14-Dec-14  0.14 33.5 414.27 265.1 13.915 90.695 125.7 1860 1680  Table C.15: UniBAR-anammox Process Effluent Characteristics with Centrate Feed (Combination 2) Effluent Characteristics (Centrate Feed)   Date pH DO (mg/L) Temp (C) Alkalinity (mg/L) NH4-N (mg/L) NO2-N (mg/L) NO3-N (mg/L) PO4-P (mg/L) TSS (mg/L) VSS (mg/L) N-removal (%) P-removal (%) 24-Jun-14 6.38  27.50 164.30 117.15 0.25 71.69 110.10 490 450 81.54 -8.40 25-Jun-14 6.63 0.06  227.90 158.40 0.47 86.87 128.10 170 140 79.83 12.67 27-Jun-14 6.41 0.08 26.80 150.70 162.25 0.77 111.98 131.40 490 430 79.44 -0.69 1-Jul-14 6.44 0.10 27.50 142.45 198.00 0.27 154.28 130.50 440 350 80.30 13.14 4-Jul-14 6.73 0.09 27.30 242.05 261.80 0.48 200.82 139.20 160 90 74.32 14.80 7-Jul-14 6.55 0.06 27.10 162.57 303.05 0.53 249.17 143.10 390 320 68.28 8.56 8-Jul-14 6.65 0.07 26.90 196.43 321.57 0.75 256.29 145.80 190 220 67.74 2.53 9-Jul-14 6.54  26.90 194.68 298.65 0.53 253.57 132.00 450 350 52.15 -1.15 11-Jul-14 6.55 0.08 26.80 158.96 343.75 0.58 282.12 150.90 230 140 62.54 4.97 12-Jul-14 6.61 0.09  205.17 331.65 0.75 275.35 154.20 200 110 66.48 6.52 14-Jul-14 6.72 0.15 27.20 216.26 322.30 1.05 258.00 157.50 170 100 67.82 7.83 17-Jul-14 6.54 0.17 27.00 169.86 298.65 0.93 242.17 156.30 490 450 65.21 -4.17 Appendix C 177  Effluent Characteristics (Centrate Feed) Date pH DO (mg/L) Temp (C) Alkalinity (mg/L) NH4-N (mg/L) NO2-N (mg/L) NO3-N (mg/L) PO4-P (mg/L) TSS (mg/L) VSS (mg/L) N-removal (%) P-removal (%) 21-Jul-14 6.65 0.16 27.10 209.78 265.65 0.73 196.72 152.10 180 140 63.52 -2.49 23-Jul-14 6.60 0.09  215.73 238.70 0.59 170.27 145.40 150 130 62.78 -0.14 24-Jul-14 6.40 0.07 26.40 134.06 177.10 0.00 156.24 124.50 450 380 51.96 -30.79 25-Jul-14 6.43 0.08 26.60 167.11 199.65 0.09 165.46 135.90 370 280 57.40 -25.07 6-Aug-14 6.50 0.09 26.70 161.50 151.80 0.72 125.23 121.50 195 170 66.97 -8.14 7-Aug-14 6.61 0.09 27.80 196.19 149.05 0.72 99.98 117.60 200 190 69.06 -18.18 8-Aug-14 6.51 0.15  195.28 136.40 0.28 91.41 111.00 730 660 71.75 -0.55 12-Aug-14 6.50 0.13 27.30 136.50 137.50 0.51 96.40 117.90 300 270 71.73 -5.98 14-Aug-14 6.54  27.10 145.80 136.77 0.78 98.07 131.10 240 210 72.86 -10.59 19-Aug-14 6.51 0.12 26.90 140.60 141.35 0.64 101.99 120.60 800 700 74.99 -0.49 26-Aug-14 6.16 0.08 26.90 159.66 203.50 0.47 157.28 132.60 220 240 73.73 0.57 27-Aug-14 6.33 0.09 26.80 148.34 191.95 0.67 149.48 131.70 190 200 79.12 15.75 28-Aug-14 6.40 0.09 28.80 165.49 140.20 0.58 140.75 115.70 250 210 84.85 0.72 29-Aug-14 6.35 0.09  167.58 155.71 0.64 142.64 116.40 290 240 82.96 0.85 30-Aug-14 6.30   176.18 177.64 0.55 165.80 121.89 320 230 80.81 -0.47 2-Sep-14 6.27 0.09 29.10 206.95 200.20 0.61 179.79 125.10 980 980 78.57 0.94 3-Sep-14 6.30 0.15 28.80 142.47 231.55 0.59 181.02 117.60 960 760 68.33 2.91 4-Sep-14 6.28 0.17 27.20 135.83 234.85 0.63 214.37 127.50 850 980 70.59 8.55 16-Sep-14 6.48 0.12 27.50 190.21 248.60 2.00 235.14 118.70 1260 1030 61.96 11.78 17-Sep-14 6.67 0.13  150.80 331.10 2.11 278.39 121.40 1040 840 49.72 7.40 18-Sep-14 6.56 0.11 26.80 161.73 325.70 2.09 269.50 126.20 860 710 51.53 9.37 19-Sep-14 6.64 0.10 26.70 176.03 330.74 1.96 260.13 129.90 740 640 50.20 3.53 20-Sep-14 6.72 0.09 27.50 188.90 359.15 2.18 282.17 123.60 950 950 45.46 7.60 Appendix C 178  Effluent Characteristics (Centrate Feed) Date pH DO (mg/L) Temp (C) Alkalinity (mg/L) NH4-N (mg/L) NO2-N (mg/L) NO3-N (mg/L) PO4-P (mg/L) TSS (mg/L) VSS (mg/L) N-removal (%) P-removal (%) 21-Sep-14 6.69 0.11 27.30 174.92 356.10 2.12 270.64 128.90 400 500 47.13 2.88 23-Sep-14 6.50 0.08 27.10 175.43 342.10 0.82 264.36 127.40 560 620 37.10 2.21 24-Sep-14 6.60 0.09 26.90 156.87 312.26 0.69 258.69 124.80 460 510 47.63 3.73 25-Sep-14 6.71 0.12 26.90 152.76 355.60 0.72 266.85 126.70 810 740 39.40 4.39 28-Sep-14 6.77 0.15 26.80 157.32 360.42 0.65 274.35 125.65 640 880 45.59 4.42 29-Sep-14 6.75 0.07  189.30 376.75 2.39 288.01 125.10 760 500 44.24 3.18 5-Oct-14 6.72  27.20 163.92 274.35 1.92 233.83 114.40 900 610 58.69 0.91 6-Oct-14 6.71 0.11 27.00 194.98 290.75 2.37 265.98 119.70 870 840 55.47 0.35 7-Oct-14 6.60 0.10 27.10 194.65 238.70 1.62 223.98 115.20 720 660 62.43 -0.09 8-Oct-14 6.56 0.09 26.90 191.53 253.00 1.34 228.01 117.90 600 570 62.70 -1.05 9-Oct-14 6.70 0.11 26.90 188.27 247.50 1.14 218.86 114.60 1020 960 65.12 1.56 14-Nov-14 6.60 0.10 28.10 131.19 231.00 2.72 190.88 116.10 130 160 65.3 -6.9 19-Nov-14 6.56 0.09 28.20 142.79 200.75 2.77 137.48 125.70 600 540 70.83 26.33 10-Dec-14 6.60 0.11 27.30 137.33 117.15 0.78 80.51 111.90 100 110 82.83 -4.08 11-Dec-14 6.50 0.10 28.10 151.54 131.45 0.77 84.10 123.30 60 40 84.23 -0.48 13-Dec-14 6.71 0.09 27.60 262.56 213.95 25.25 94.66 125.70 90 90 75.76 -0.24 14-Dec-14 6.67 0.11  414.27 289.85 42.19 88.72 125.70 140 100 65.40 -1.21   

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