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The use of oxidation-reduction potential (orp) as a process a process control parameter in wastewater.. 1992

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THE USE OP OXIDATION-REDUCTION POTENTIAL (ORP) AS A PROCESS CONTROL PARAMETER IN WASTEWATER TREATMENT SYSTEMS by DAVID GERAINT WAREHAM B.A.Sc.(Civil Engineering), The University of Waterloo, 19 M.A.Sc.(Civil Engineering), The University of Waterloo, 19 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in THE FACULTY OF GRADUATE STUDIES (Department of Civil Engineering) We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA January 1992 David Geraint Wareham, 1992 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, Iagree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. (Signature) Department of C i v i l Engineer ing The University of British Columbia Vancouver, Canada Date January 27 1992 DE-6 (2/88) ii ABSTRACT This research explored the use of Oxidation-Reduction Potential to control two lab-scale sequencing batch reactor (SBR) wastewater treatment processes. The treatment schemes investigated were the aerobic-anoxic digestion of activated sludge (AASD) and the excess biological phosphorus (Bio-P) removal process. Evaluation of each process consisted of a consideration of the reactor performances coupled with the control stability achieved using two different operating strategies. The first strategy was known as "Fixed-Time Control" (FT), since it represents the "classical" management approach; control is based on conditions externally "fixed" by an operator. For the AASD set of experiments, the "fixed" variable was the ratio of air-on to air-off (3 hours each). For the Bio-P experiments, it was the time of addition of acetate to the reactor (1 hour 25 minutes into the non-aerated sequence). The second strategy was known as "Real-Time Control" (RT), since it represents an optimization technique whereby control conditions are continuously evaluated as time progresses. The Real-Time aspect of control is derived from the fact that ORP measurements evaluate the reactor conditions on-line, by invoking a bacterial vision of the process scheme. For the AASD experiments, this evaluation took the form of proportioning the ratio of air-on to air-off, based upon the bacterial "need" for sufficient time to reduce the nitrates completely to nitrogen gas (denitrification). Sufficient time is i determined by the distinctive breakpoint (correlated to nitrate disappearance) occurring in the ORP-time profile. The first experiment (AASD#1) , therefore, had an air-on/air- off ratio of 3 hours air-on/nitrate-breakpoint-determined air- off. The second experiment (AASD#2) had the length of aeration time determined by a match to the previous length of time for denitrification, as determined by the breakpoint. In the Bio-P experiments, the ORP breakpoint was used to "trigger" the addition of acetate to the reactor, thus ensuring the maximum amount of carbon was available for storage by Bio-P organisms. Comparisons between the two reactors revealed that for the AASD strategies, the Real-Time reactor had essentially the same solids degradation as the Fixed-Time reactor (14% - 21%), depending upon the strategy considered, the type of solids (TSS or VSS) and the method of mass balancing used. The RT reactor was observed to obtain marginally better nitrogen removal (up to 6 % in some cases) over the FT reactor. Evaluation of the ORP parameter as a "response indicator", by subjecting the AASD reactors to unsteady process input conditions, revealed that the Real-Time reactor more readily accommodated disturbances to the system. Neither reactor in the Bio-P experiment was particularly successful in consistently removing phosphorus. A potentially useful screening protocol was developed for evaluating reactor performances, based upon the time-of-occurrence of the nitrate breakpoint, assessed against whether it hindered or aided the purpose of acetate addition to a Bio-P SBR. iv TABLE OF CONTENTS Page ABSTRACT ii TABLE OF CONTENTS iv LIST OF TABLES vi LIST OF FIGURES viii ACKNOWLEDGEMENTS xii GLOSSARY OF TERMS xiii 1 INTRODUCTION 1 1.1 Proj ect Need 1 1.2 Research Approach and Objectives 4 2 OPERATING THEORY AND LITERATURE REVIEW 7 2.1 Oxidation-Reduction Potential (ORP) 7 2.1.1 Redox Theory 7 2.1.2 Microbiological Aspects: Intracellular Redox.... 11 2.1.3 Physical Characteristics: Probe Operation 18 2.2 Applications of Oxidation-Reduction Potential 21 2.2.1 General Activated Sludge Processes 21 2.2.2 Fermentation Studies: ORP Control 24 2.2.3 ORP Control of Wastewater Treatment Processes... 2 6 2.3 ORP and Aerobic-Anoxic Sludge Digestion (AASD) 29 2.4 Biological Phosphorus (Bio-P) Removal and ORP 34 2.5 Sequencing Batch Reactors (SBRs) 37 2.5.1 Overview of Operation 37 2.5.2 SBR Applications in Wastewater Treatment 41 3 EXPERIMENTAL METHODS AND ANALYTICAL TECHNIQUES 43 3.1 Source of Feed Sewage and Sludge 43 3.2 Experimental Set-Up and Design 45 3.2.1 General Structural Configuration 45 3.2.2 Electronic Hardware 50 3.2.3 Computer Software 54 3.3 Raw Feed Collection Procedures 61 3 .4 Operating Control Strategies 62 3.4.1 Aerobic-Anoxic Sludge Digestion #1 (AASD#1).... 62 3.4.2 Aerobic-Anoxic Sludge Digestion *2 (AASD*2).... 66 3.4.3 Biological Phosphorus Removal (Bio-P) 67 V TABLE OP CONTENTS CONT'D Page 3.5 Analytical and Sampling Techniques 69 3.5.1 General Procedures 69 3.5.2 Suspended Solids Measurements 70 3.5.3 pH, Alkalinity, Diss. Oxygen and Temperature.... 71 3.5.4 ORP Measurements 71 3.5.5 Nitrogen Analysis 72 3.5.6 Phosphorus Analysis 73 3.5.7 Estimates of Carbon Content 74 3.6 Sample Preservation and Storage Techniques 74 3 . 7 Statistical Techniques 76 4 AEROBIC-ANOXIC SLUDGE DIGESTION EXPERIMENTS 77 4.1 Review of Special Features of ORP Curves 77 4.2 Operational Characteristics 83 4.2.1 Technical Considerations 83 4.2.2 Experimental Pre-Run Conditions 90 4.3 Behaviourial Trends: AASD#1 Experimental Conditions... 92 4.3.1 Operating Characteristic and ORP Profiles 92 4.3.2 General Observations: Chemical Parameters 98 4.3.3 Mass Balances: Solids, Nitrogen and Phosphorus. 108 4.3.4 Evaluation: Unsteady Process Input Conditions.. 112 4.4 Behaviourial Trends: AASD*2 Experimental Conditions.. 123 4.4.1 Operating Characteristics and ORP Profiles 123 4.4.2 General Observations: Chemical Parameters 132 4.4.3 Mass Balance Perspective 137 4.4.4 Evaluation: Unsteady Process Input Conditions.. 141 5 BIOLOGICAL PHOSPHORUS REMOVAL EXPERIMENTS 149 5.1 Operating Characteristics and ORP Profiles 149 5.2 Chemical Characteristics of Bio-P Experiments 160 5.3 Evaluation of Reactors: Breakpoint Categories 185 6 CONCLUSIONS AND RECOMMENDATIONS 195 6.1 Conclusions 195 6.2 Recommendations 198 REFERENCES 201 APPENDIX A - Derivation of Nernst Equation 212 APPENDIX B - Intracellular Redox and Energy Calculations... 214 APPENDIX C - Software Flowcharts all Experiments 216 APPENDIX D - Software Code all Experiments 227 APPENDIX E - Chemical Data AASD*1, AASD#2 Experiments 258 APPENDIX F - Mass Balances - AASD*1 and AASD#2 270 APPENDIX G - Calculations for Bio-P Experiments 289 APPENDIX H - Chemical Data for Bio-P Experiments 291 vi LIST OF TABLES Table Page 2.1 Selected List of Electrode Half-Reactions and their Standard Electrode Potentials 9 3 .1 Components of Experimental Apparatus 48 3.2 Subroutines and Functions in Each Experiment 56 3 . 3 Timing of Phases in a Bio-P SBR 68 3.4 Sample Preservation, Analysis and Storage Techniques 75 4.1 Selected List of Chemical Statistics: AASD*1 99 4.2 Mass Balances for Fixed-Time Reactor: AASD#1 110 4.3 Mass Balances for Real-Time Reactor: AASD#1 110 4.4 Particulars of Sodium Nitrate Spikes: AASD#1 114 4.5 Particulars of Ammonium Chloride Spikes: AASD#1 114 4.6 Particulars of Hydrogen Peroxide Spikes: AASD#1 114 4.7 Failures Associated with FT Reactor Operation: AASD#1 124 4.8 Failures Associated with RT Reactor Operation: AASD*1 124 4.9 Selected List of Chemical Statistics: AASD#2 133 4.10 Mass Balances for Fixed-Time Reactor: AASD#2 139 4.11 Mass Balances for Real-Time Reactor: AASD#2 139 4.12 Particulars of Sodium Nitrate Spike: AASD*2 142 4.13 Particulars of Ammonium Chloride Spike: AASD#2 142 4.14 Particulars of Hydrogen Peroxide Spike: AASD*2 142 4.15 Failures Associated with FT Reactor Operation: AASD*2 146 4.16 Failures Associated with RT Reactor Operation: AASD*2 146 5.1 Solids, Nitrogen and Phosphorus Chemical Data: Bio-P#l 162 vii LIST OF TABLES CONT'D Table Page 5.2 Solids, Nitrogen and Phosphorus Chemical Data: Bio-P*2 163 5.3 Carbon, Oxygen, Alkalinity and pH Data: Bio-P*l 172 5.4 Carbon, Oxygen, Alkalinity and pH Data: Bio-P#2 172 5.5 Breakpoint Classification Categories: Bio-P#l 193 5.6 Breakpoint Classification Categories: Bio-P*2 193 viii LIST OP FIGURES Figure Page 2.1 Typical Bacterial Electron Transport Chain 14 2.2 Diagram of ORP Electrode and Operation 2 0 2.3 Diagram of 5 Operating Periods of Bio-P SBRs 40 3 .1 UCT Bio-P Process 44 3 . 2 UBC Bio-P Process 44 3 . 3 Schematic of Experimental System 4 6 3.4 Schematic of AASD and Bio-P Sequencing Batch Reactors 47 3 . 5 Impedance Diagram of ORP-Amplif ier Circuit 52 3.6 Illustration of Linear Ring-Buffer Concept 59 3.7 Illustration of BREAKPT Capture of Nitrate Knee 59 4.1 Fixed-Time ORP Profile Under AASD Conditions 78 4.2 Real-Time ORP Profile Under AASD*1 Conditions 81 4.3 Effect of Relatively Fresh Feed on Reactor ORP Curves 84 4.4 Overlay of First-Difference and ORP-Time Profiles 84 4.5 Linear Diagram of Components Identifying Problem Areas 85 4.6 Reactor Interaction Effects Due to Improper Grounding 87 4.7 ORP Profile Affected by Intermittent Electrical Noise 89 4 . 8 Complete Deterioration of ORP Profile 89 4.9 Unusual Response Pattern: No Nitrate Breakpoint 91 4.10 Unusual Response Pattern: No Diss. Oxygen Breakpoint... 91 4.11 "Switch Over Day": FT to RT Control - AASD#1 93 4.12 Temporal Reproducibility of ORP Curves in RT Reactor... 94 v ix LIST OP FIGURES CONT'D Figure Page 4.13 Spatial Reproducibility of 3 ORP Electrodes in Same Reactor 96 4.14 Anoxic-Zone-Length: Cyclical Pattern Due to Daily Feed 97 4.15 Anoxic Periods Greater Than the 3 Hour Fixed-Time Limit 97 4.16 Daily Variation in Feed and Reactor TSS: AASD#1 101 4.17 Parallel Plot: Feed Sludge AASD*1 TSS/VSS Ratio 101 4.18 Fluctuations in Total Nitrogen Content: AASD#1 102 4.19 Fluctuations in Total Phosphorus Content: AASD*1 102 4.20 Fixed-Time Reactor: pH vs. Time for AASD#1 107 4.21 Real-Time Reactor: pH vs. Time for AASD#1 107 4.22 General Case of Mass-Balance Around Reactor 109 4.23 High Spike of Sodium Nitrate to FT Reactor: AASD#1.... 115 4.24 High Spike of Sodium Nitrate to RT Reactor: AASD#1.... 115 4.25 Low Spike of Ammonium Chloride to FT Reactor: AASD*1. . 116 4.26 Low Spike of Ammonium Chloride to RT Reactor: AASD*1. . 116 4.27 High Spike of Hydrogen Peroxide to FT Reactor: AASD*1. 117 4.28 High Spike of Hydrogen Peroxide to RT Reactor: AASD*1. 117 4.29 Typical "Incomplete Nitrification Failure" 119 4.30 "False-Knee" Failure in Real-Time ORP Profile 119 4.31 Fixed-Time Reactor Response to Missed Feed: AASD#1.... 122 4.32 Real-Time Reactor Response to Missed Feed: AASD*1 122 4.33 "Switch Over Day": FT to RT Control - AASD*2 126 4.34 Real-Time ORP Profile Under AASD#2 Conditions 127 4.35 RT Profile AASD*2 - Missed Feed Day Nov/11/90 128 4.36 RT Profile AASD*2 - Missed Feed Day Nov/12/90 128 X LIST OF FIGURES CONT'D Figure Page 4.37 "Missed-Knee" Failure in Real-Time ORP Profile 130 4.38 Two "Missed-Knee" Failures During Single Day 131 4.39 Daily Variation in Feed and Reactor TSS: AASD*2 135 4.40 Daily Variation in Feed and Reactor VSS: AASD#2 135 4.41 Fluctuations in Total Nitrogen Content: AASD#2 136 4.42 Fluctuations in Total Phosphorus Content: AASD#2 136 4.43 Daily Variation in Feed and Reactor pH: AASD#2 138 4.44 Daily Variation in Alkalinity: AASD#2 138 4.45 Spike of Sodium Nitrate to FT Reactor: AASD#2 143 4.46 Spike of Sodium Nitrate to RT Reactor: AASD#2 143 4.47 Spike of Ammonium Chloride to FT Reactor: AASD#2 144 4.48 Spike of Ammonium Chloride to RT Reactor: AASD*2 144 4.49 Spike of Hydrogen Peroxide to FT Reactor: AASD#2 145 4.50 Spike of Hydrogen Peroxide to RT Reactor: AASD*2 145 4.51 Spike of Potassium Cyanide to FT Reactor: AASD*2 148 4.52 Spike of Potassium Cyanide to RT Reactor: AASD*2 148 5.1 "Ideal" ORP Profile Under Bio-P Conditions 151 5.2 Software Failure Due to Rapid Denitrification 151 5.3 Fixed-Time Reactor Track Study: Bio-P*l 153 5.4 Real-Time Reactor Track Study: Bio-P#l 153 5.5 VFA-Caused Breakpoints in Fixed-Time Reactor 155 5. 6 VFA-Caused Breakpoints in Real-Time Reactor 155 5.7 Fixed-Time Reactor Track Study: Bio-P#2 156 5.8 Real-Time Reactor Track Study: Bio-P*2 158 5.9 Decline in Carbon Content: Stored in Cold Room 159 xi LIST OF FIGURES CONT'D Figure Page 5.10 Decline in Carbon Content: Stored in Feed Bucket 159 5.11 Delay in Time of Nitrate Breakpoint Occurrence 161 5.12 Two Day Track of Delayed Nitrate Breakpoint 161 5.13 Variation in Feed and Effluent TSS: Bio-P*l 164 5.14 Variation in Feed and Effluent TSS: Bio-P*2 164 5.15 Variation in Reactor TSS: Bio-P*l 166 5.16 Variation in Reactor TSS: Bio-P*2 166 5.17 Reactor Plot of Percent N and P: Bio-P*l 168 5.18 Reactor Plot of Percent N and P: Bio-P#2 168 5.19 Track of Ortho-P Concentrations: Bio-P*l 169 5.20 Track of Ortho-P Concentrations: Bio-P*2 169 5.21 Variation in Feed and Reactor COD: Bio-P*l 173 5.22 Variation in Feed and Reactor COD: Bio-P*2 173 5.23 Carbon (TC, IC, TOC) Plots for Feed: Bio-P#l 174 5.24 Carbon (TC, IC, TOC) Plots for Feed: Bio-P#2 174 5.25 Carbon (TC, IC, TOC) Plots for FT RCTR: Bio-P#l 176 5.26 Carbon (TC, IC, TOC) Plots for FT RCTR: Bio-P*2 176 5.27 Variation in pH Feed, FT and RT RCTRS: Bio-P*l 178 5.28 Variation in pH Feed, FT and RT RCTRS: Bio-P*2 178 5.29 Breakpoints Classified According to Acetate Use 188 5.3 0 Nine Day Track of Denitrification Time 188 5.31 Disruption of Reactor Due to Solenoid Failure 190 5.32 Disruption of Reactor Due to Mixer Failure 192 ACKNOWLEDGEMENTS The interdisciplinary nature of this research is reflected in the variety of backgrounds, associated with the many individuals to whom I have become indebted, during the course of my stay at UBC. Firstly, I would like to thank my supervisors, Drs. K. J. Hall and D. S. Mavinic for their patience and guidance during the difficult times of this research. Furthermore, I am indebted to the Natural Sciences and Engineering Research Council of Canada (NSERC) for the financial support they provided via grants to my supervisors. I would like to acknowledge both the excellent technical assistance and the moral support of Susan Liptak, Paula Parkinson, Romy So, and Jufang Zhou, who cheerfully demonstrated the use of the lab instruments and always co-operated to the fullest extent, making the lab a pleasant environment within which to work. I am also grateful to Guy Kirsch, for his skilled modifications to the lab apparatus, to Paul Milligan, John Wong and Dr. Peter Lawrence for their advice and assistance in solving the electrical problems, to Rod Nussbaumer and Jim Greig for their software support and Fred Koch for his explanation of fundamentals. Thanks are owed to my many fellow graduate students, among others, Yves Comeau, Kirk Morrison, Pat Coleman, Bruce Anderson, Fongsatitkul Prayoon, and Takis Elefsiniotis, all of whom provided their unique brand of advice, humour and comradery, making my UBC experience most enjoyable. Special thanks are in order for Tim Ma for his companionship, availability and general willingness to discuss any of life's intricacies both inside and outside of the laboratory. Also valued is the on-going interest and support of both my families in Ontario. Their many calls of encouragement were deeply appreciated. Finally, I would like to thank my beloved wife Julia, whose constant love, encouragement and spiritual support has been a real boon to me, as together we have endeavoured to know Him who is the author of all knowledge. GLOSSARY OF TERMS General Terms AASD Aerobic-Anoxic Sludge Digestion (*1 and #2) ATP/ADP Adenosine Triphosphate/Diphosphate Bardenpho Barnard Denitrif ication Phosphorus Removal Process Bio-P Biological Phosphorus Removal (*1 and *2) COD Chemical Oxygen Demand D.O Dissolved Oxygen F:M Food:Microorganism Ratio HRT Hydraulic Retention Time MLSS/MLVSS....Mixed Liquor Suspended Solids/Volatile SS N (%) Nitrogen NAD/NADH+ Nicotinamide Adenine Dinucleotide ORP Oxidation-Reduction Potential P (%) Phosphorus PHA/B/V Poly-B-hydroxyalkanoates/butyrates/valerates RCTR Reactor SBR Sequencing Batch Reactor SCFA Short Chain Fatty Acids SRT Sludge (Solids) Retention Time TC/TOC/IC Total/Total Organic/Inorganic Carbon TKN/TP Total Kjeldahl Nitrogen/ Total Phosphorus UBC/UCT University of British Columbia/Cape Town VFA Volatile Fatty Acid Important Terms Specific to Program Acetate Acetate not added to RT reactor yet Baseaddr% The Base Address of the A//D Board (&H220) ChanO%/15%....Lower (0) and Upper (15) Bounds of channels Delta2a/2b/2c.The Critical ORP Slope Difference (-1.25) Flagdiff No Preceding Point in First Difference SUB Flagloop For Breaking into and out of Scanning Loop Flag.RT Real-Time Control Requested by User Flagscrn Flag to Invoke Graphics Display Ioadr% The Base Address of the Relay Board (&H330) KY.ESC For Escaping/Terminating Program KY.LN For <No> Decision Finished Viewing Probes KY.LY For <Yes> Decision to Select Other Probes Max.Anox Fail-Safe Limit to Resupply the Air Maxavoid Variable Safety Factor Before Search for Knee Nitrate Flag Signalling Nitrate Breakpoint Detected Num.Channels..Number of Channels to be Scanned (16) Num.Pts Dimensioning of Screen Display (181) Numrings The number of Rings in the Buffer (5) Num.Scans Number of Scans/2 minute interval (60) Realtime Flag - Initially no Real-Time Control Renew Flag to Clear/Reset Breakpoint Subroutine Ringsize The width of the BREAKPT Ring (5) Scan.Time Polling interval for the probes (2 seconds). VFAPass Counter to time the VFA Pump Operation VFAPump Flag to Signal VFA Pump On or Off 1 CHAPTER 1 INTRODUCTION 1.1 Project Need The fundamental theories of wastewater treatment have been well understood for many years. In recent times however, the emphasis has moved towards acquiring better control of the unit processes, thereby treating a waste more efficiently. A greater ability to control inherently returns benefits in the form of less wasteful unit operations, since specific control parameters can be fine-tuned at will to optimize system performance. Classical examples in wastewater treatment include matching aeration supply to oxygen demand (to avoid overaeration) and correlating food supply to microbial biomass. The escalating demand for better control has generated in its wake a demand for increased reliability and development of sensing instruments. At the forefront of this movement are instruments capable of making in situ measurements, a fact already attested to by the development of the on-line dissolved oxygen probe. Even more recently the advent of the microcomputer has brought automation to the sewage treatment field. For example the International Association on Water Pollution Research and Control (IAWPRC) has sponsored a series of workshops (London and Paris (1973), London and Stockholm (1977) , Munich and Rome (1981), Houston and Denver (1985), and Yokohama and Kyoto (1990)), specifically devoted to the interchange of technical information on instrumentation and control of water and wastewater treatment and transport systems. 2 Instrumentation, control, and automation (ICA) is clearly an expanding field for research and development and interest in its application to wastewater treatment systems (and water supply in general) shows no signs of abatement. In the very early years computers were employed simply as "plotters", recording operational data and doing elementary evaluations, such as printing maintenance lists (Lohmann, 1985) and/or tracking the number of occurrences in which data exceeded threshold limit values. In the eighties and now nineties, computers are moving beyond the data acquisition / process monitoring stage, to being increasingly used for more sophisticated wastewater treatment applications. Examples abound and range from complex forms of information management, linked through workstations (Williams et al., 1986), to process control (Vaccari et al., 1988). When coupled with reliable sensors they can provide rapid information, particularly with regards to real-time disturbances. At the very least, computers commonly alert operators to problem area(s), while some computers possess enough sophistication to analyze both the problem scope and to implement remedial action. In addition a computer offers a major advantage over traditional hardwired systems (composed of timers and relays) due to the relative ease with which the sequencing logic can accommodate (through changes in either its format or time-base) improvements in the operating procedure. As will be emphasized in Chapter 2, interest in Oxidation- Reduction Potential (ORP) has recently been renewed, partly as a result of the search for new process control parameters to couple with the innovative technologies being developed. Earlier criticisms regarding the meaningfulness of ORP measurements in biological systems (Harrison, 1972) have been re-evaluated in light of the knowledge that the emphasis can be transferred from the absolute value of the ORP (which is admitted to having debateable usefulness (other than in the most general sense of an environment being oxidizing or reducing)) to the ORP variation with time. For example, there is no question that ORP- time profiles in acclimated sludges undergoing alternating aerobic-anoxic sequences, contain certain distinctive features which can be correlated with known physical and chemical events of theoretical and engineering interest (Peddie et al, 1988b). One such feature is the nitrate breakpoint or "knee" associated with the disappearance of nitrates in the ORP-time profile. (Section 4.1). This phenomenon correlates to the bacterial transformation from respiratory to non-respiratory processes, and has been well documented (Koch and Oldham, 1985) in both aerobic-anoxic sludge digestion (Jenkins, 1988) and biological phosphorus removal (Comeau et al., 1987a) processes. The regular occurrence of this feature provides a powerful impetus for process control. The major truth evident here is that although the ORP probe does not achieve a well-defined thermodynamically-reversible equilibrium value (suggesting a specific solution composition of speciated ions), this should not hinder its use as a process control parameter in wastewater treatment systems. As long as 4 the system is sufficiently electroactive to generate (at least at the electrode level) an observable biologically-meaningful response pattern, it reflects a reality which ultimately can be exploited for control purposes. Thus this research addresses the need to re-evaluate the usefulness of the ORP probe as a process control parameter in light of the recent advances in computer and control technology. For example, the marked instability so often characteristic of past ORP measurements in biological wastewater and sludge treatment systems, can be easily smoothed out as part of the interfacing equipment before the signal is processed by the host computer. Elimination of these extreme fluctuations allows the computer to more readily control the process, based upon consistent detection of a real and reproducible feature in the ORP-time profile. 1.2 Research Approach and Objectives The basic objective of this research is to demonstrate the usefulness of Oxidation-Reduction Potential, for automated control of Sequencing Batch Reactor (SBR) sewage treatment processes. More precisely, ORP-based process control is demonstrated in two specific wastewater treatment processes, the first accommodating the solids residuals generated from a sewage treatment plant (Aerobic-Anoxic Sludge Digestion (AASD)) and the second investigating bio-nutrient treatment of raw sewage (Biological Phosphorus (Bio-P) Removal). Control is based, in both cases, on the nitrate breakpoint phenomena which occurs in the ORP profile with time (Section 4.1). 5 Two operating strategies (more fully discussed in Chapter 3) are considered in the AASD set of experiments (Chapter 4). The first strategy (AASD*1 - Section 3.4.1) compares a control reactor (Fixed-Time Control) (operating with a "Fixed" 3 hour air-on, 3 hour air-off aerobic/anoxic sequence) to an experimental reactor (Real-Time Control) operating with a cycle partition of 3 hours air-on but a variable length of time for air-off, contingent upon computer detection of the nitrate knee. The second strategy (AASD#2 - Section 3.4.2) compares a control reactor operating as above (Fixed-Time mode), with an experimental reactor, now operating with the length of aeration time determined by a match to the previous time for air-off (i.e. the length of the preceding anoxic cycle). At the time this research was proposed, no information was available on whether an ORP-driven, 50/50 air-on/air-off mode of operation, would collapse in on itself due to the rapid on/off sequences. Conceivably, if the process showed stability (under what is likely a "stressful" operating strategy), there could be grounds for investigating an operating strategy which further shortened the cycle length, operating between an ORP-detected "nitrate knee" and an ORP-detected "dissolved oxygen elbow" (Section 4.1). This would essentially represent an oscillating balance between nitrification and denitrification, thus considerably saving the air supply associated with the dissolved oxygen plateau of the ORP-time curve (Section 4.1). The Bio-P experiments (Chapter 5) compare a control reactor (operating with a "Fixed" time, (1 hour 25 minutes) for the addition of volatile fatty acids to the anaerobic regime) to an experimental reactor using nitrate breakpoints, to time the addition of acetate to the anaerobic phase of the cycle. In both sewage processes an attempt has been made to evaluate the effectiveness of ORP as a process control parameter. In the AASD experiments, this included detailing the stability and responsiveness of the ORP controlled system to several stresses, (both artificial and natural). In the Bio-P experiment, this involved categorizing the nitrate breakpoints according to whether or not their time of occurrence maximized the objective of VFA addition to the process. For example, some breakpoints occurred well after the addition of VFAs, meaning that some of the acetate was likely used by denitrifers to reduce nitrates, rather than being exclusively used by Bio-P organisms for carbon storage. 7 CHAPTER 2 OPERATING THEORY AND LITERATURE REVIEW 2.1 Oxidation-Reduction Potential (ORP) 2.1.1 Redox Theory Many ubiquitous processes found in the natural world can be reduced to electro-chemical reactions involving the transfer of electrons from one species to another. A substance which gains electrons is said to be reduced (in a reduction reaction), while a substance which loses electrons is said to be oxidized (in an oxidizing reaction). Since some species gain or lose electrons more readily than others, (a function of the number of electrons in the outer shell and the size of the atom or ion (Westcott, 1976)), a table of Standard Electrode Potentials can be compiled and is to be found in any standard text on water chemistry (ex. Benefield et al., 1982). To assign a Standard Electrode Potential to a substance, unit activities of its oxidized and reduced forms are connected via a platinum wire and salt bridge, to a hydrogen half-cell containing water (pH = 0 , (1 M H+) , T = 25 °C) and hydrogen gas at one atmosphere pressure. The electrode potential is the voltage that would have to be applied to prevent electrons flowing to or from the test half cell. By convention, a positive voltage means that the electrons are flowing from the hydrogen half-cell to the sample, while a negative voltage is defined when the electron flow is from the sample to the hydrogen half-cell. 8 Table 2.1 shows a selected subset of some of the half-reactions pertinent to this research (written as reduction equations). All of the equations shown are those substances which have a strong affinity for accepting electrons. They are allocated large positive potentials with respect to the hydrogen half-cell (arbitrarily assigned a zero volt potential), since the reaction as written has a strong tendency to proceed to the right. In contrast, those substances which lose electrons most easily (i.e. have the least tendency to exist in a reduced state), would be assigned more negative potentials with respect to the hydrogen half-cell. As indicated, the reactions are half-reactions, that is, for every reduction equation there exists a complementary oxidation equation. Thus both the oxidized and reduced forms of a particular redox couple can concurrently exist in solution. Therefore, oxidation-reduction potential (ORP) is a measurement which establishes the ratio of oxidants to reductants prevailing within a solution of water or wastewater (ASTM, 1983). In contrast to pH which measures a specific acid/base couple (in effect the hydrogen ion activity), the ORP measurement is non-specific (i.e. not a specific redox couple); instead, it senses the prevailing net direction of all electron transfers occurring, and thus the net solution potential is in effect the electron activity (Petersen, 1966). 9 Table 2.1 Selected List of Electrode Half-Reactions and their Standard Electrode Potentials Reaction E° (Volts) H+ + e" <=> 1 /2 H2 ( g ) C0 2 ( g ) + 8H+ + 8e" <=> CH4(g) + 2H20 A 9 C 1 < s ) + e " < = > A 9 ( S ) + C 1 " S04 2" + 9H+ + 8e" <=> HS" + 4H20 H<?2C12<s> + 2 e ~ < = > 2H9<i> + 2 C 1 ' SO 2- + 10H* + 8e" <=> H,S,.% + 4H,0 2'-'Cg) I2(aq) + 2 e ' <=> S I " N03" + 2H+ + 2e" <=> N02" + H20 N03" + 10H+ + 8e" <=> NH4+ + 3H20 N02" + 8H+ + 6e" <=> NH4+ + 2H20 2N03* + 12H+ + lOe" <=> N2( } + 6H20 0 „ a , + 4H+ + 4e" <=> 2H,0 2Caq) 2 Cr 2 0 7 2 " + 14H+ + 6e" <=> 2Cr 3 + + 7H20 C12(aq) + 2 e * < = > 2 C 1 " 0 . 0 0 + 0 . 1 7 + 0 . 2 2 + 0 . 2 4 + 0 . 2 7 + 0 . 3 4 + 0 . 6 2 + 0 . 8 4 + 0 . 8 8 + 0 . 8 9 + 1 . 2 4 + 1 . 2 7 + 1 . 3 3 + 1 . 3 9 Note : (1) All reactions with respect to the hydrogen standard electrode and at T = 25°C. (2) List drawn from larger list presented in Snoeyink and Jenkins, 1980 Water Chemistry) 10 The ORP is expressed in mathematical form by the Nernst equation as shown below. For the Reaction: Ox + ne" = Red (2.1) The Nernst Equation: Eh = E° + RT ln{Ox/Red} (2.2) nF where: Ox - Oxidized species. Red - Reduced species. n - number of electrons participating in the reaction. Eh - the voltage difference (V) between the oxidation- reduction half cell and the standard hydrogen electrode. E° - the voltage difference occurring in a pure system (i.e. when the activities of all oxidants and reductants are unity and at 25 °C) . R - Universal Gas Constant (8.315 joules/ °K/mole). T - temperature - degrees Kelvin. F - Faraday Constant (96,500 coulombs/equivalents). {} - the activity of the oxidized and reduced species. The derivation of the Nernst equation, arising from consideration of the interaction between the Gibbs Free energy equation and the Van't Hoff equation is included in Appendix A. In practice, the gaseous hydrogen electrode is rarely used as the reference electrode, due to certain physical difficulties, such as bubbling hydrogen gas at 1 atmosphere pressure through a solution. The Eh however, can always be obtained by adding the measured potential to the potential of the reference electrode. The most common reference electrodes are the Ag/AgCl and the calomel electrode (Section 2.1.3). 11 2.1.2 Microbiological Aspects: Intracellular Redox Molecular oxygen is the most powerful oxidizing agent found in natural water systems, since anything stronger would begin to react with the abundant surrounding water and liberate oxygen. Redox reactions initiated with oxygen as the oxidizing agent, should be quite slow based on theoretical considerations, since the solubility of oxygen in water is low (Henry's Law predicts 2xl0"4 mol/L). Moreover, kinetic restraints arise since the synchronous transfer of 4 electrons (Table 2.1) to completely reduce oxygen to water is highly improbable, since most electron donors supply at best one or two electrons per molecule. It is a well known fact however, that organic matter can be metabolized by living cells. Micro-organisms do not actually perform the chemical reactions, instead they catalyze them and use the material for purposes such as deriving energy for metabolic processes or as source materials for biosynthesis (Snoeyink and Jenkins, 1980). Thus the biochemical reduction of oxygen to water can take place extremely rapidly because biological systems have circumvented the need for multi-stage reduction (i.e. separate one or two electron steps) by using enzymes in which several electron donor centres are present in the same molecule and which ultimately provide all four electrons required (Eilbeck and Mattock, 1987). This fundamental principle is exploited in biological treatment systems designed to specifically oxidize the organic constituents in wastewater. A detailed description of the many and various 12 metabolic pathways, specific enzymes, energy balances and methods of phosphorylation etc. is beyond the needs of this research; however, any good text on microbiology (ex. Tortora et al. (1982)) can supply most of the necessary details. For the brief purpose of illustration however, the biochemical degradation of the energy-yielding carbohydrate glucose will be considered. Equation 2.3 describes the complete oxidation of this cellular fuel in the presence of oxygen to carbon dioxide and water. C6H12°6 + 602 = = > 6C02 + 6H2° AG 0 = -686 kcal/mole (2.3) If a bacterial cell were to burn glucose in this manner (i.e. one step), it would literally burn itself up. Instead, the cell invokes a metabolic pathway that involves numerous stages, each catalyzed by its own specific enzyme and characterized by a free energy change that is rarely more than a few (ex. 10) kcal/mole (Dyson, 1974). The first step usually involves the removal of two hydrogen atoms (with the accompanying two electrons) via the enzyme dehydrogenase. This is followed by several other sequential stages in which some of the intermediate products produced are broken down yet again. In terms of the specific route taken, numerous metabolic pathways exist (depending upon the physical environment and the ability of a specific organism to utilize a particular path); however, the most common pathway is the Tricarboxylic Acid (Krebs or TCA) Cycle (when respiration is occurring aerobically) and the Glycolytic (Embdon-Meyerhoff) Pathway (when non-respiratory processes such as fermentation are 13 employed). The TCA cycle becomes an extension to the glycolytic pathway when oxygen or a combined form of it becomes available to an organism that can use this path. At several points in the pathway the energy in the electrons is captured by one of a class of electron deficient carrier molecules such as nicotinamide adenine dinucleotide (NAD+) , which is reduced to a high energy level compound NADH. Since NAD* is generally in short supply in the cell, the rest of the cells efforts are directed towards regenerating the pool of NAD* by one of several mechanisms. Again if NAD+ was regenerated by directly combining with oxygen, NADH + H+ + 1/2 02 ==> NAD+ + H20 A G ° = -53.8 kcal/mole (2.4) the resulting free energy change' of 53.8 kcal/mole (calculated in Appendix B) , would still be too large to be captured by a single adenosine triphosphate (ATP) molecule (or its equivalent) and much of the energy would be lost as heat (Boyd, 1984). The most efficient way to regenerate NAD+ (i.e. maximizing the capture of energy) is to transfer the electrons from NADH to oxygen in a series of discrete steps via the electron transport chain. The electron transport chain (Figure 2.1) located in the cytoplasmic membrane of prokaryotes, consists of a series of closely linked electron carrying species, such as flavins, quinones and certain proteins containing metal ions. The NADH passes its electrons to the first carrier molecule in the chain and in the process regenerates NAD+. Each couple then reduces the 14 Inner Portion Cell Membrane NADH > + H NAD 1Q,+ 2H \\0 Electron Carrier Molecules ATPase Outer Portion ~ H - H H Figure 2.1 Typical Bacterial Electron Transport Chain (Adapted from Tortora et al., (1982)) 15 next in line until the terminal electron acceptor is reached and reduced to its final form. Each of the electron carriers in the respiratory chain has its own characteristic ORP. Electrons gravitate from more negative carrier molecules to more positive ones and therefore this governs the structure of the chain. Moreover, there is a small decline in free energy between adjacent molecules in the chain. The magnitude of the energy release is directly proportional to the difference in magnitude of the intracellular redox potentials of adjacent molecules. At certain strategic points (three when oxygen is the final electron acceptor), there is a sufficient drop in free energy that a high energy phosphate can be donated to adenosine diphosphate (ADP) to form ATP (a process known as oxidative phosphorylation). ATP is the most common energy reserve molecule or retrievable form of energy currency in which the micro- organism stores energy; however, other energy reserve molecules do exist. The micro-organism can draw upon this energy bank by coupling ATP hydrolysis to unfavourable reactions that need to be driven such as some biosynthesis processes. It is estimated that for every mole of glucose oxidized aerobically to C02 and water (via the glycolytic pathway/TCA combination), 38 ATP-like molecules are formed (Boyd, 1984). As shown in Appendix B, this represents a 39-45 % capture of the original energy (686 cal/mole) stored in a mole of glucose molecules. This can be compared with the mere 2 ATP molecules generated by the incomplete oxidation of glucose under anaerobic conditions (i.e. ATP generation by substrate level phosphorylation) by organisms that halt at the end of the glycolytic pathway. Thus aerobic organisms grow much faster than anaerobic organisms because the potential for energy release during aerobic respiration is much greater than anaerobic conditions, since many electron pairs are released and shuttled down the chain to produce ATP. A facultative organism for example might require 48 hours of optimal growth conditions to produce a population of cells that, under aerobic conditions, could be established in 16 hours or less (Boyd, 1984) . Many micro-organisms possess the capability of using an alternate terminal electron acceptor in the electron transport chain, if their primary choice is unavailable. For example, Pseudomonas and Bacillus can use nitrates; however, they only utilize them when the concentration of dissolved oxygen is minute or nonexistent, since fundamentally they are unable to extract as much energy per mole out of doing so. Again, when nitrate is utilized, the reaction to produce N2 (gas) is favoured over the reduction of N03" through N02" to NH4+ because it yields more useable energy to the micro-organism catalyzing it (using the enzyme nitrate reductase) (Snoeyink and Jenkins, 1980). Again, this is a function of the intracellular redox levels of the various reaction couples. Other bacteria are restricted to the use of one electron acceptor such as Desulfovibrio which reduces sulphate (S04"2) to hydrogen sulphide (H2S) . Still others use carbonate (C03"2) to form methane (CH4) . A few microbes anaerobically use 17 compounds such as fumardc acid as the final electron acceptor. Depending upon the electron donor, the micro- organism, the pathway chosen and the terminal electron acceptor, the number of ATP molecules generated from the chain may be only 1 or 2 rather than 3 when free oxygen is used. As mentioned, this essentially translates to the difference in the oxidation reduction potential between the donor (NADH) and the final electron acceptor. In this general sense the intracellular redox level helps to determine the type of biological community that develops. The exact relationships between the intracellular redox level, the NADH level and the extracellular ORP probe measurement is subject to on-going research (Wang and Stephanopoulos (1987), Armiger et al. (1990)). Nicotinamide adenine nucleotides are known to be the coenzymes of a good fraction of the intracellular oxidation-reaction steps, and therefore by following the NADH/NAD* level important process control strategies can be formulated. In fact, Armiger et al (1990) have already demonstrated how a fluorescence method (which measures the ratio of NADH to NAD*) can be used to provide a characteristic "fingerprint" of the optimal operation of a bionutrient removal process. This procedure is very similar to the method used in this research except that it assesses the reductive (rather than the oxidative) status of the sludge. Whatever the exact relationship between intracellular and extracellular redox is, there is little question that the external ORP reading is a direct reflection of 18 the activity at the cellular level. This is not to imply that ORP is the sole governing mechanism that drives the community type. It can be appreciated that in a wastewater treatment system there is both a complex mix of micro-organisms and a virtual "cocktail" of organic wastes. Which reactions are used is still very much a function of the physical environment. However, whether a particular ORP value is the cause or effect of a given bacterial population is of secondary importance, for the correlation between the two is real enough (Whitfield, 1969) such that a link of this kind can be effectively exploited. 2.1.3 Physical Characteristics: Probe Operation Electro-chemical theory suggests two kinds of electro-chemical cells. The electrolytic cell occurs when non- spontaneous reactions are forced to proceed by the external application of a voltage across the two electrodes. Thus, electrical energy is consumed during the reaction. Conversely, the Galvanic cell, of which type the ORP electrode is representative, is an electro-chemical cell in which the spontaneous occurrence of electrode reactions produces electrical energy. The ORP electrode consists of a reference electrode (ex. silver/silver chloride or calomel) and an indicating electrode constructed of a highly noble metal (ex. platinum or gold). The reference electrode or cathode has a fixed potential since the concentration of the cation associated with the electrode metal is maintained through the solubility-product principle. The reference electrode is separated from the test solution by a porous ceramic plug which allows charged ions to pass through to each solution preventing charge differentials building up and halting the reactions. A highly noble (inert) metal is chosen as the anode primarily because its potential for oxidation is less than that of any oxidizable components in the test solution. The anode therefore ideally should not participate in any reaction, but rather just provide a surface for the oxidation of the solution constituents. The area of the noble metal in contact with the test solution should be approximately 1 cm2 (ASTM 1983) . A sketch of the ORP electrodes used throughout the duration of this research is shown in Figure 2.2. In order to describe how the probe functions, it is assumed that initially the probe is immersed in a highly reducing environment, that is, one in which anaerobic respiration processes prevail (ex. sludge which has been unaerated for several hours). The organic materials in the sludge are continuously subjected to degradation by bacterial enzymes and thus a variety of numerous, successive and parallel biological reactions occur as electrons are shuttled back and forth between oxidized and reduced species. Some of the electrons will naturally gravitate along the platinum wire to the cathode, since the Ag/AgCl reference electrode has a large positive electrode potential of +.22 volts (Table 2.1). The silver chloride paste will then undergo a reduction equation forming solid silver and free chloride ions as shown in Equation 2.5. 20 Rubber Cap Sliver Metal Strip Coated with AgCI Paste Eauatlon AgClw + e" = = > Ag, CATHODE Ceramic Porous Junction Allows passage of K and CI Ions to Maintain Electroneutralfty Shielded Coaxial Cable Electrolytic Gel Saturated 4.2 N KCI Fills the Interior of the Electrode Glass Exterior Organic Material is laced with Electrons 9 Platinum Band (Noble Metal) ANODE °J c°, ®. Oz + 4e" + 4H+ = = > 2^0 Figure 2.2 Diagram of ORP Electrode and Operation 21 AgCl(s) + e" ==> Ag(s) + CI' (2.5) Again by convention, when the flow of the electrons is from the test solution to the reference electrode the ORP value recorded is negative. Upon introducing a continuous supply of oxygen into the solution, many of the electrons normally travelling to the reference electrode will be enzymatically rerouted towards reducing the oxygen to water, since it has an even larger positive potential (E° = 1.27 (Table 2.1)) than the reference Ag/AgCl electrode. As the number of electrons travelling along the platinum wire diminishes, so too will the ORP value become more positive. Eventually the flow of electrons will reverse itself, consistent with the definition that when the flow is from the reference electrode to the test solution the ORP is defined positively. Therefore, in any given water system, the variation of ORP potential with time may serve as a relative guide to the oxidizing or reducing conditions in that system (Bockris, 1972). 2.2 Applications of Oxidation-Reduction Potential 2.2.1 General Activated Sludge Processes A survey of the relevant literature indicates that interest in ORP as applied to activated sludge processes, flourished for the most part during the middle years of this century. Researchers such as Rohlich (1948), Hood (1948), Eckenfelder and Hood (1951), and Nussberger (1953) investigated and debated the significance of ORP measurements, primarily in aerobic treatment processes. It quickly became evident that exact potentials for aerobic and anaerobic regimes of a treatment process were questionable (Rohlich, 1948), since measurements varied widely both between plants and amongst probes inserted in the same tank within a given plant. However, Rohlich (1948) did maintain that the time-potential ORP curves could be used to maintain better operational control of a sewage treatment plant. Despite initial optimism, a note of caution dictated that perhaps the most that could be said was that ORP showed promise, as a diagnostic tool to indicate whether aerobic or anaerobic conditions prevailed (Hood, 1948). Nussberger (1953) (in an effort to practically integrate ORP into the routine operation of a step-aeration sewage treatment plant) developed a series of characteristic ORP curves, which he proposed could be used as a guideline to indicate whether a plant was being under- or overloaded, and under- or overaerated. The next spate of papers occurred roughly 10 years later, commencing with the research of Grune and Chueh (1958). This again involved investigating ORP variability in sewage treatment plants. Some of the research however began to concentrate more closely on the practical aspects of control such as aeration. For example, O'Rourke et al, (1963) used ORP to estimate the utilization of the aeration capacity of an aeration basin. Rudd et al., (1961) and Roberts and Rudd (1963) demonstrated that the diurnal rise in ORP (corresponding to the noonday decline in sewage throughput to the plant) could be used to scale back aeration on-line time, thus realizing significant 23 economic benefits. In an interesting discussion to Grune and Chueh 's paper, Eckenfelder (1958), in commenting about his own work, notes that both the rate of change of the ORP potential and the ultimate ORP value reached is of importance. In several tests, inflection points (sharp breaks in the ORP profile with time) could be correlated to the disappearance of an oxidant or reductant such as oxygen or sulphate. This seems to be the earliest recorded reference to a breakpoint phenomena. The wide fluctuations in ORP readings are partly a result of the fact that, in biological systems, the ORP is a mixed potential, that is, it is a potential that is derived from many concurrent electro-chemical reactions, none of which (in open systems) are in equilibrium. As Stumm (1966), and Morris and Stumm (1967) comment "... for a multi-redox component system, that is not in equilibrium.... the redox potential (which is by conceptual and operational definition, an equilibrium potential) becomes meaningless." Harrison (1972) concluded that the overall redox potential seemed to be of little value in studies of growing microbial cultures. Such criticisms coupled with the appearance of a reliable commercially-available dissolved oxygen probe (Koch and Oldham, 1985) tended to effectively dissipate the initial interest displayed in discovering the role ORP played in sewage treatment processes. For the most part, ORP was all but forgotten for the next two decades except for some sporadic citations such as Dickenson (1969). He sought to characterize the relative ease with which an aerated sludge could oxidize a substrate, based upon the recovery profile of the ORP-time curve, after the sludge had received a slug dose of the substrate of interest. Other notable exceptions were researchers such as Blanc and Molof (1973) who continued to direct efforts towards understanding the role ORP measurements played in anaerobic systems where, by definition, the D.O. probe was not applicable. In particular, in some anaerobic digestion studies, they were able to correlate specific ORP ranges (-450mv to -550mv, Ec) to good production of methane. 2.2.2 Fermentation Studies: ORP Control The use of oxidation-reduction potential in fermentation research has been the focal point of several studies for a considerable period of time (Wimpenny, 1969, Wimpenny and Necklen, 1971, and Kjaergaard, 1976). Many aerobic microbial fermentation processes take place at concentrations of dissolved oxygen (D.O.), which are impossible to measure using commercial dissolved oxygen probes. It is important however, to have some tool which can effectively provide information about the degree of oxygen limitation to the culture (Kjaergaard, 1977). The useful operating range of the redox probe is much larger than the D.O. probe due to the availability of negative redox potentials. Thus, Shibai et al. (1974) was able to show a good correlation between Eh and very low oxygen concentrations (as measured by an oxygen analyzer) in studying inosine fermentation processes. 25 In a review of several investigations into ORP values and microbial cultures, Kjaergaard (1977) noted special interest evidenced in the fluctuations in the ORP value as it related to the efficiency of production of particular metabolites. Their own work experimented with the regulated addition of glucose controlled by maintaining a constant redox potential in the medium. Upon depletion of the initial glucose media, the microbial oxygen consumption would decrease, reflected in an increase in both the oxygen level and ORP value. Since ORP is more readily measurable in the micro-aerophilic range than D.O., any change in its value could be easily detected and used to close a relay. This initiated a pump which delivered glucose until the redox potential returned to its original value. Since the additional glucose was used by the microorganism before a new pulse was added, the growth of the organism (and consequently the production of the metabolite) was also regulated. The use of ORP setpoints in fermentation studies has continued to grow and further work (Kjaergaard and Joergensen, 1979, 1981) led to the proposition that ORP could be classed as a "state variable" in fermentation systems operating at minute dissolved oxygen levels. Dahod (1982), investigating the production of penicillin, maintained that ORP was a much better parameter than dissolved oxygen for fermentation process control, primarily because D.O. measures only the oxidizing potential of the 02 metabolic chain, while redox measures the oxidizing potential of all the species formed in the broth (i.e. all oxidation chains). This can be critical when mass transfer limitations create a discrepancy between the oxygen concentration in the bulk phase and the actual oxygen availability (Wang and Stephanopoulos, 1987). This will cause other electron acceptors to be employed. Radjai et al. (1984) searched for the best redox conditions to optimize the production of amino acids such as homoserine, valine and lysine. The flow of dissolved oxygen to the fermentation broth was varied by manipulating the agitator speed and the change in the ORP value was recorded. The specific ORP value corresponding to the optimum production rate of the amino acid was noted and this value was once again used as an ORP setpoint in further pure culture work. 2.2.3 ORP Control of Wastewater Treatment Processes Interest in ORP and its applications to wastewater treatment systems has been rekindled as advances in automation have led to a search for reliable process control parameters. Burbank (1981), discusses several field experiences, in which operators examined the ORP fluctuations with time and made appropriate operating decisions for the plant. Many of their resolutions correspond to the type of observations and guidelines Nussberger had proposed almost 3 0 years earlier. Poduska and Anderson (1981) discuss the use of ORP to control hydrogen sulphide odours, which develop during warm weather spells in lagoons storing aerobically digested sludge. Application of a local industry's wastestream (40 % NaN03) was shown to be effective in eliminating odours due to the preferential selection of electron acceptors (ie. N03" over S04"2) in metabolism. A specific ORP setpoint was not used; however, a high positive ORP value (> +100 mv) was shown to be effective in controlling odours. Eilbeck (1984) investigated breakpoint chlorination of free and metal complexed ammonia, in wastestreams originating from metal finishing and electronic industries. Redox titration curves were superimposed on the chlorine breakpoint curves and the sharp jump in redox when the residual chlorine broke through was noted. Prior to the breakpoint, the ORP remained constant as chloramine complexes were formed with hypochlorous acid. Thus the redox breakpoint, detecting when a residual became available, was of great assistance in ascertaining dosage rates. Rimkus et al. (1985) used ORP to control raw sewage odours generated when low weather flows into the Chicago O'Hare Water Reclamation Plant (a combined sewer inlet) led to the production of hydrogen sulphide. A computer continuously analyzed ORP signal inputs and when the ORP dropped below +100 mv, sodium hypochlorite was added to increase the ORP. Sekine et al., (1985) described an activated sludge process which used ORP as a supervisory index for nitrification. A circuit converted the ORP value into a nitrification rate (based on experimental observations) and made a time-series correction to the D.O. value to obtain good nitrification. Watanabe et al. (1985), in a series of lab experiments, used an ORP setpoint of approximately -150 mv to control the addition of an external carbon source (methanol) in order to ensure 28 denitrification. As the biomass exhausted the carbon, the ORP would rise above the setpoint and initiate methanol addition. In this way , ORP became a control index for methanol regulation and allowed consistent effluent NOx-N levels of less than 1 mg/L. Charpentier et al., (1987) discussed both laboratory and full scale applications of ORP control in France. In a low loaded activated sludge plant, various NH4* and N03" effluent concentrations were recorded along with the attendant variations in ORP. Subsequently, ORP values of -80 to +120 mv were targeted and air was cycled on and off to the aeration basin, at a rate just sufficient to keep the ORP between these limits. In this way, consistent effluent nitrogen levels were maintained. They concluded that with redox based control, electricity consumption could be more accurately determined, thanks to constant regulation of the aerators correlated to specific pollution levels. Research into ORP continues to progress as investigators have recognized the potential ORP offers for in situ process control. Heduit and Theunot (1989) mention that the constants in the relationship between the D.O. concentration and ORP (of the form Eh = a + b log[02]) depend upon the sludge loading, the aeration conditions, the sludge concentration and other redox species. Charpentier et al., (1989) furthered this work by investigating relationships between effluent nitrogen and ORP. They found that targeting upper and lower ORP values in the aeration cycle, simultaneously optimized the effluent quality 29 and electrical costs. De la Menardiere (1991) in a similar study, observed high removal levels for carbon, nitrogen and phosphorus as a function of targeting different ranges for the ORP values in the aeration basin. Both of these latter two studies make some poignant observations relating to ORP inflection points and nitrate disappearance. They comment about the possibility of new ORP applications using these inflection points in the control of biological nutrient removal processes. 2.3 ORP and Aerobic Anoxic Sludge Digestion (AASD) One of the most significant expenditures associated with the construction and operation of a pollution control plant, is the cost of stabilization and disposal of the waste activated sludge solids. Estimates vary but are generally in the range of 40-50 % of the total cost (both capital and operating) of the wastewater treatment plant (Rich, (1982), Evans and Filman (1988)). For small plants (< 5 MGD) an attractive option is to aerobically digest the sludge, since this method is not as prone to process upsets, which can periodically afflict the anaerobic digesters in larger plants. Aerobic digestion is somewhat similar to extended aeration, except that there is assumed to be no influent source of carbon other than that derived through the auto-oxidation (endogenous respiration) of the bacterial protoplasm itself. An obvious disadvantage of aerobically digesting sludge is the energy cost associated with a continuous supply of air. In addition, since aerobic digestion processes tend to consume alkalinity as shown in Equation 2.7 (the bacterial mass is assumed to be represented by the chemical formula Cglî Ĉ  (Hoover et al., 1952)), there is an added chemical cost to maintain the pH in the neutral range. C5H7N02 + 702 ==> 5C02 + 3H20 + N03" + H+ (2.7) Currently, there are at least 20 digesters in B.C. aerobically treating waste activated sludge (Minister of Supply and Services Canada, 1981). Recently, a modified form of the conventional aerobic sludge digestion process has been proposed (Hashimoto et al., 1982). This involves an additional anoxic tank which receives the nitrate-rich effluent of the aerobic tank and denitrifies it according to the equation below. C5H7N02 + 4N03" ==> 5C02 + NH3 + 2N2 +40H" (2.8) This not only reduces more volatile suspended solids but also acts to reduce the total nitrogen content generated in the sludge digestion process. A more innovative design that appears to significantly offset the major disadvantages of aerobic digestion, is the practice of cycling the air in an on/off manner. This method intrinsically induces considerable savings in energy (air supplied) as well as reduces or even eliminates the extra chemical cost (since, during the anoxic portion, alkalinity is recovered (Equation 2.8)). Moreover there is no need for an additional tank as the previous solution (Hashimoto et al., (1982)) proposed. The first published research into this sludge digestion method appears to be that of Warner et al., (1985) . They discuss aerobic-anoxic theory as a subset of the general activated 31 sludge model, originally developed by Dold, Ekama and Marais (1980) and extended by van Haandel, Ekama and Marais (1981). This model, based on steady state activated sludge theory, is flexible enough to incorporate nitrification-denitrification, variable influent conditions and series reactor configurations. It can predict COD removal, nitrification-denitrification, alkalinity changes, oxygen demand and volatile solids degradation. The major conclusions of this research (from both theoretical considerations and lab scale experimental data) was that the incorporation of anoxic intervals in aerobic digestion of waste activated sludge, did not appear to adversely affect the degradation rate of the active bug mass, provided the anoxic portion of the cycle was not overly long. According to their observations the anoxic segment should not comprise more than 50 to 60 % of the total cycle length, nor should the duration of any single anoxic portion of the cycle be greater than 3 hours. It was also noticed that, for the digesters operating at a 50 % anoxic time, the nitrate generated by the nitrification reaction (during the aerobic portion of the cycle) was completely denitrified during the anoxic portion of the cycle. This meant that sufficient alkalinity was generated to keep the pH stable and in the neutral range. The balancing effect of alkalinity and pH resulting from an alternating aerobic-anoxic sequence has subsequently been well documented (Peddie et al., (1988a), (1988b), Jenkins, (1988)). Matsuda et al., (1988) followed the transformation of 32 nitrogen and phosphorus in the solid and liquid phases, while comparing aerobic-anoxic vs. continuous aerobic sludge digestion. Some interesting profiles were presented; however, their major conclusion was that the reduction rate of sludge solids and the behaviour of nitrogen and phosphorus under intermittent aeration (controlled by a D.O. criteria) was substantially equivalent to that undergoing continuous aeration. Therefore, intermittent aeration could be considered a viable method of sludge digestion with its attendant economic benefits. Jenkins and Mavinic (1989a) investigated the solids degradation obtained using three different sludge digestion operating strategies (aerobic/anoxic (2.5 air-on/ 3.5 air-off), aerobic with lime addition and straight aerobic). Further to this, when operating the digesters at 3 different SRTs (10, 15 and 20 days) and two different temperatures (10 °C and 20 °C) , it appeared that cycling the air flow gave comparable results in terms of percent TVSS reduction, while using only 42 % of the air that continuous aeration would employ. In addition, aerobic/anoxic sludge digestion maintained a neutral mixed liquor pH at almost no extra cost. They postulated that comparable results were attainable because the bacteria made more efficient use of the air, since prior to initiation of the air, the driving force would be quite high, (enabling greater oxygen transfer efficiency once air resupply commenced). Furthermore, during the anoxic portion of the cycle, endogenous respiration would still be in effect (with nitrates as the terminal electron acceptor), so that some 33 reduction in solids would continue to occur. Microbial degradation by nitrates and more efficient oxygen transfer efficiency was essentially the same rationale offered earlier by Ip et al., (1987), who investigated the savings in aeration energy costs encountered when air was cycled on and off (controlled by a D.O. probe) to a normal continuous flow activated sludge system. In a subsequent paper, Jenkins and Mavinic, (1989b) detailed the benefits accrued from the AASD operating strategy in terms of improved supernatant quality (ex. reduction of nitrates through denitrification during the anoxic portion of the cycle) . They also used ORP as a tool to monitor the aerobic/anoxic sludge digesters and clearly showed that the ORP profile with time was reproducible from cycle to cycle. Moreover, in developing an overall rating system to evaluate the performance of the three digestion modes, the potential for automation, based upon ORP, resulted in AASD receiving the highest ranking in this category (Jenkins 1988). Finally, Kim and Hao (1990) investigated aerobic-anoxic sludge digestion, specifically focusing in on the kinetics of the anoxic phase and how it related VSS degradation to the endogenous nitrogen respiration (ENR) rate. They recognize that the in situ placement of an N03" probe could modify the duration of the cycle period in a SBR to accommodate the required nitrate consumption pattern. This is a very similar concept to the one explored in this research. 2.4 Biological Phosphorus (Bio-F) Removal and ORP Perhaps of most significance in terms of rekindling interest in ORP, was the development of bio-nutrient removal processes (Koch and Oldham, 1985). These designs incorporate a non-aerated regime in the process train, a domain in which the dissolved oxygen probe is rendered inadequate but the ORP probe remains useful. In conventional activated sludge systems, the typical phosphorus content (based on dry weight) is 1.5 to 2.0 percent (U.S. EPA, 1987). This is primarily composed of the phosphorus taken up by microbes for use in biomass synthesis (i.e. phospholipids, nucleotides, and nucleic acids etc.). In the late fifties and early sixties, researchers such as Levin and Shapiro, (1965) and Shapiro et al., (1967) reported that up to 80 % of the phosphorus in activated sludge could be removed by vigourous aeration, while much of this was re-released at the bottom of the secondary clarifier, under conditions of low or zero dissolved oxygen. It was apparent, therefore, that some microbes could take up phosphorus in excess of normal metabolic requirements, a phenomenon that eventually became known as excess biological phosphorus (Bio-P) removal. As mentioned, the Bio-P process modifies the activated sludge process by including a non-aerated zone prior to the aerobic reactor. Addition of simple short-chain carbon substrates to this zone, (ex. volatile fatty acids such as acetate or propionate) result in a phosphorus release to the liquid, accompanied by a corresponding microbial carbon storage in the form of either poly-B-hydroxybutyrate (PHB) or poly-B- hydroxyvalerate (PHV). Together, these carbon storage compounds are known generically as poly-B-hydroxyalkanoates (PHA) (Comeau et al., 1987b). When the biomass is subsequently subjected to carbon- limiting, aerobic conditions, those bacteria which have previously sequestered carbon in reserves, seem to evidence a competitive advantage over other organisms. In fact, in the aerobic zone, the competition is restricted to that fraction of carbon which is not so readily biodegradable; thus, Bio-P organisms, drawing upon their exclusive access to the stored carbon, proliferate in greater numbers and, in doing so, take up not only the phosphorus they initially released in the anaerobic zone, but also much more than normal metabolism would dictate. A typical biological phosphorus removal plant might have up to 6-10 percent P in the sludge (U.S. EPA, 1987). This P seems to be complexed into polyphosphate reserves which the bacteria can break down and utilize for "maintenance/survival" energy, when again subjected to conditions in which there are no usable terminal electron acceptors available (i.e. anaerobic conditions). In the early stages of Bio-P research, Shapiro et al., (1967) considered ORP significant enough to monitor and suggested it as a possible factor governing phosphate release. He observed that the rapid release of phosphorus in the anaerobic zone appeared to occur around an ORP value of -150 millivolts. However, Randall et al., (1970) concluded that 36 phosphate release was not a function of, nor dependent upon, ORP since release often occurred before any significant change in the ORP level. Countering this, Barnard (1976) proposed that ORP had potential in characterizing the degree of anaerobiosis at the front end of a Bio-P plant. He stated this because it appeared that a certain minimum level of ORP had to be reached to ensure good P removal. Barnard eventually developed a modification of his Bardenpho (Barnard Denitrification Phosphorus) nutrient removal process, titled the Phoredox process, because of the lower redox potentials that could be achieved in the anaerobic zone. However, Barnard later abandoned the theory of a minimum anaerobic stress level in favour of the availability of simple carbon substrates as being the prerequisite for good P release. In a series of batch experiments Koch and Oldham, (1985) traced the ORP-time profile, in essence temporally modelling the spatial progress of a biomass/organic waste through a Bio-P plant. One important discovery was the existence of a reproducible nitrate breakpoint (or knee) in the ORP-time profile, corresponding to the transformation between respiratory and non-respiratory processes. This breakpoint also correlated to the onset of anaerobic phosphate release, a key phenomenon in biological phosphorus removal. Koch and Oldham's experiments acted both to dispel some of the theoretical ambiguity in interpreting the ORP measurement and to counter the lack of enthusiasm which had plagued the use of ORP over the last several years. Further to these experiments, routine monitoring and visual inspection of ORP levels has become an integral part of recent biological nutrient removal research carried out at the University of British Columbia (Comeau et al., 1987a, 1987b, Zhou (1991)). Additional work by Koch et al., (1988) sought correlations between ORP values and nitrate, ortho-phosphate and dissolved oxygen concentrations, in several biological regimes particular to the bio-nutrient removal process. Several equations were derived relating ORP to dissolved oxygen, nitrate and phosphate concentrations. Since these equations are all sludge specific, no attempt has been made to verify them in this research. Furthermore, the sludge specificity of the equations makes the applicability of such equations questionable. The authors of the above research do acknowledge observed shifts over the course of the experiment, in the coefficients for regressions; therefore, there is certain to be variation in this research, done a few years later with a totally different sludge. This research, therefore, has elected to avoid regressions of this nature, abandoning them in favour of highlighting general behavioral trends, not only for the Bio-P experiments (Chapter 5) but also for the AASD set of experiments (Chapter 4). 2.5 Sequencing Batch Reactors (SBRs) 2.5.1 Overview of Operation Sequencing batch reactors are in essence, modern day versions of the draw-and-fill systems used in the early days of sewage treatment (U.S. EPA, 1986). The original systems were fairly time intensive in nature, since they required an operator 38 to manually feed and draw the reactors at appropriate times, and initiate the various sequences during the day. The use of draw- and-fill reactors tended to fade naturally with the advent of modern continuous flow through systems (CFS); however, since the SBR system merely provides in time what the CFS provides in space, these latter systems were adopted primarily from operational considerations and not from any process-related weaknesses of the batch system (Arora et al., 1985). Recent advances in technology such as the use of timer controlled pumps, solenoids, level sensors and microprocessors etc. have obviated the need for operator controlled functions and revived interest in SBR technology. Following the convention adopted by the studies done at the University of Notre Dame, Indiana (Irvine and Busch, 1979) the operation of an SBR can be divided into 5 discrete operating periods entitled... (i) FILL - the receiving of the raw waste; (ii) REACT - the time to complete the desired reaction(s); (iii) SETTLE - the time to separate the organisms from the treated effluent; (iv) DRAW - the discharge of both the treated effluent and waste solids (if necessary) and; (v) IDLE - the time after the effluent is discharged and before refilling. One or more of these periods may be omitted depending upon the control strategy desired, however at the very least all tanks must contain the FILL and DRAW periods (as for 39 example in an equalization tank). A sketch of the 5 periods during one cycle is shown in Figure 2.3. Advantages of an SBR system are numerous and make it ideal for small communities which experience wide variations in influent flows and strength. Some of the more obvious benefits include (Arora et al., (1985)... (i) Acting as an equalization tank during FILL it has an ability to balance peak flows and absorb shock loads; (ii) The effluent may be held until it meets specific objectives; (iii) The MLVSS cannot be washed out by hydraulic surges; (iv) There is no need for return activated sludge (RAS) pumping since the mixed liquor is always in the tank and; (v) Solid-liquid separation occurs under near ideal quiescent conditions since short circuiting is non- existent during the settle period. Furthermore there is no need for an extra tank for clarification since the same tank can serve as both a biological reactor and a clarifier. Probably the most readily apparent advantage is the SBR's flexibility of operation. Easy adjustment of the microprocessor timer settings, allows timed intervals to be changed to permit different modes of operation. For example, a portion of the REACT period can be reserved for aeration to allow for nitrification while another portion can be dedicated to the denitrification process. Biological phosphorus removal 40 INFLUENT FILL Add Substrate do Min Volume Max Volume REACT forat SETTLE Activated Sludge Intel face Waste to Control SRT DRAW Remove Clarified Effluent IDLE c t o Figure 2.3 Diagram of 5 Operating Periods of Bio-P SBRs strategies can also be implemented in this way. Furthermore, a liquid level sensor could be adjusted to allow only a fraction of the tank capacity to be used during the early years of the design life, without wasting power through overaeration. Finally, if more than one tank is used in series, tanks can be put on or offline to allow for seasonal variation. 2.5.2 SBR Applications in Wastewater Treatment Several recent studies at the University of Notre Dame (Alleman and Irvine (1980a, 1980b), Palis and Irvine (1985)), the University of California, Davis (Silverstein and Schroeder (1983), Abufayed and Schroeder (1986a, 1986b), and the University of Manitoba (Oleszkiewicz and Berquist (1988), McCartney and Oleszkiewicz (1988, 1990)) have investigated nitrification and denitrification in sequencing batch reactors. Primarily monitoring several SBR performance characteristics, most of the studies were able to consistently remove a very high percentage of the organic carbon and nitrogen in the wastewater. Sequencing Batch reactors have also be used to remove phosphorus both chemically (Ketchum and Ping-Chao Liao (1979), Ketchum et al. (1987)) and biologically (Manning and Irvine (1985), Vlekke et al., (1988)). Again the inherent flexibility of an SBR system allows the proper mix of anoxic, anaerobic and aerobic conditions necessary for Bio-P removal. In particular a control strategy must be selected which at a minimum eliminates oxidized nitrogen and dissolved oxygen during the FILL (anaerobic) period and allows for aeration during the REACT period (Manning and Irvine, 1985). The increased interest in SBRs has been reflected in the number of studies done on full scale applications in recent years. Irvine et al., (1983, 1985, and 1987) have examined the operational performance of full scale SBRs at Culver, Indiana and Grundy Centre, Iowa under high and low loaded conditions and depending on the study have reported excellent effluent quality in terms of BOD5, SS, N and P removal despite varying influent conditions. Melcer et al., (1987) examined the conversion of small municipal wastewater treatment plants in Manitoba to sequencing batch reactors and reported that it was technically and economically feasible to convert the existing small-scale package plants and septic tanks to SBRs over the flow ranges studied (4 to 227 m3/d) . 43 CHAPTER 3 EXPERIMENTAL METHODS AND ANALYTICAL TECHNIQUES 3.1 Source of Feed Sewage and Sludge The University of British Columbia's Environmental Engineering Group manages a pilot-scale sewage treatment plant located about 2 kilometres south of the UBC campus. The facility, housed in a renovated tractor trailer unit, generally operates in a biological phosphorus removal mode. More specifically, it is a modified version of the well known University of Cape Town (UCT) process (Figure 3.1), routinely depicted in papers published by South African researchers (eg. Seibritz et al., 1983). This modified configuration will henceforth be referred to as the UBC version (Figure 3.2) to distinguish it from its UCT predecessor. The process, treating primarily campus wastewater (and a small fraction of household domestic waste) is designed so that the operator can choose (by way of baffle insertion) the proper mix of alternating aerobic, anoxic and anaerobic sequences necessary to ensure good biological phosphorus removal. The sludge age is usually maintained at an average age of 2 0 days; however, flexibility in piping, valves and pumps, allows SRT variations as desired. The pilot-plant facility has two process trains, labelled side "A" ( the control) and side "B" (the experimental) . Either raw sludge or raw sewage was collected from the pilot plant as the needs of the experiment dictated. For the AASD experiments, sludge was collected from the aeration basin of the control 44 LEGEND Anaerobic Anoxic [ | Aerobic Anoxic Aerobic Waste Secondary Clarffler Effluent Figure 3.1 UCT Bio-P Process LEGEND Anaerobic Anoxic Aerobic Anoxic Side A Sludge Fermerrter (Mixed) Secondary Clarifler Effluent Side B (Not used) Figure 3.2 UBC Bio-P Process 45 ("A") side in the manner which will be described in Section 3.3. The side "A" configuration includes a primary sludge fermenter to generate volatile fatty acids for later addition to the anaerobic portion of the process. In addition, external equalization tanks, plus a primary clarifier, are merged into the process train so that the aerated sludge is fairly "clean" in the sense of being uniform in nature and having very little, if any, of the organic and inorganic "problem" materials that sometimes create difficulties for a sewage treatment plant. Thus, no pre-treatment of waste sludge was required. For the Bio-P set of experiments, raw sewage was obtained from the equalization tanks in the manner also described in Section 3.3. 3.2 Experimental Set-Up and Design 3.2.1 General Structural Configuration A block diagram highlighting the major components of the research apparatus, is shown in Figure 3.3. Slightly different structural arrangements of the Sequencing Batch Reactors (SBRs) were used for the AASD and Bio-P experiments respectively, and these are illustrated in the schematic of Figure 3.4. Table 3.1 itemizes the particular model numbers of many of the experimental components. In general, the reactors were made of plexiglass (Diameter = 12 cm., Volume = 5.4 litres) and filled to the 4.8 litre mark with either activated sludge and/or raw sewage depending upon the experiment. Spigots for sampling and solenoids for decanting etc. were placed at strategic heights 46 12BrtA/D Converter Board Fixed-Time (Control) Reactor Real-Time (Experimental) Reactor Air Compressor Air Pressure Regulator Note: In actual reactor all 6 probes (i.e 3/reactor) connect to computer Figure 3.3 Schematic of Experimental System 47 Variable Speed Mixers 5.4 L Vol. 12 cm. 0 Plexiglass 4.8 L Vol. Air Supply 2.4 L Vol. MIn 3 = n Sampling Ports [f=£. Waste Settled Sludge Variable Speed Mixers Overflow 4.8 L Vol. Max Acetate Addition Effluent Drawoff Sludge Waste Influent Wastewater AASDSBR BIO-P SBR Figure 3.4 Schematic of AASD and Bio-P Sequencing Batch Reactors Table 3.1 Components EXPERIMENTAL COMPONENT Air Pressure Regulators - 2 Air Solenoids - 2 Air Flow Meters - 2 Mixing Motors - 2 ORP Probes - 3/Reactor Computer Analog-to-Digital Card Input/Output Control Card Standby Power Supply Experimental Apparatus DESCRIPTION OF ITEM Parker Model # 07R218AB MAC 113B-112CCAA Cole-Parmer PR0034-FM32-15ST Dayton DC Model #47539A Broadley-James #P114101-10BC Morse Shuttle 386-SX AT Data Translation DT2814 Metrabyte Model PIQ12 American Power Conv. UPS-SX 49 and utilized according to the operating strategy. Wasting and feeding of the sludge in the AASD experiments was done manually, while for the Bio-P experiments the liquids were pumped automatically, entering and exiting the reactors at appropriate levels. Air for both experimental sets was supplied by an in-house compressor at 410 - 550 kPa (60 - 80 psi) . Two pressure regulators, connected in series at the air supply outlet, subsequently reduced this pressure to approximately 100 kPa (15 psi). The airline was then split into two separate lines, with each line passing through an air solenoid (ON/OFF regulation controlled by computer) before continuing on through an adjustable air flow meter (rated range 55-165 mL/min). The lines then looped around below the reactor underside to flow through a diffusing stone before entering the reactor. The AASD digesters (and Bio-P reactors when in non- quiescent conditions) were completely mixed by a stainless steel shaft with an appropriate blade design. Visually, complete horizontal and vertical mixing appeared to be achieved. At three strategic points Broadley-James Corporation combination oxidation-reduction potential probes were inserted into each reactor. These probes use a Ag/AgCl reference electrode with a platinum band as the noble metal. The probes were affixed physically to one end of a piece of rigid plastic tubing which subsequently slid, with minimum resistance inside the sleeve of yet another plastic tube. This latter tube opened up through a ball valve into the interior of the reactor, acting 50 as a conduit to allow the ORP probe to slide, with some degree of ease, into and out of the reactor. An O-ring seal sandwiched between the two cylinder walls prevented liquid being forced by back-pressure from the reactor. The three probes were labelled a, b, and c to denote the front, side and back of the reactor from the perspective of facing the experiment on the computer side of the research bench. Thus, in referring to the ORP probe in the front of the right reactor (labelled RCTR#2 - Section 3.4.1) the nomenclature 0RP2a would be used. 3.2.2 Electronic Hardware In the experimental environs used in this research, the ORP probes generate a low-level voltage electrical signal in the range of -300 to +300 mV. Furthermore, the total electrode resistance is generally in the order of 10 Kohms (Petersen, 1966), thus an application of Ohm's law reveals that the current is quite small (around 30 microamps). Moreover, due to the physical construction of the probe, even larger resistances (in the order of Mohms) are possible. These subsequently produce extremely small currents, thus coaxial shielded cable was used from the probe to the computer to protect the signal from induced currents. Magnetic stirrers and water baths are among the commonest sources of noisy readings (Midgley and Torrence, 1978); however, all electric motors and any ancillary apparatus containing relay switches (ex. ovens and hotplates) were suspect. The source impedance of the probe was measured and 51 observed to be greater than 15 Mohms (Milligan, 1989). The probes were therefore connected to a custom-built amplifier (having a large input impedance (100 Mohms)) in order to more accurately measure the voltage. Figure 3.5 indicates the theory behind this, by replacing the ORP probe with an ideal voltage source (0 internal resistance) in series with a resistor having the corresponding source impedance. The largest value of Vin will occur when the input impedance of the amplifier is much larger than the internal resistance of the source (Weber and Maclean, 1979) . Sporadic results (documented in Section 4.2.1) were initially obtained due to the lack of a common ground between the coaxial shield of the probe cable (left floating) and the amplifier chassis, whose differential inputs were also both floating. Furthermore, unshielded wire inside the amplifier resulted in rampant pick-up of electrical noise. Modifications to the amplifier and elimination of ground loops eventually corrected these problems, leading to reasonably stable ORP measurements. As shown previously (Figure 3.3), the amplifier output connected to a junction box which relayed the signal through an electronic cable into the back of the computer. Inside the computer, an analog to digital (A/D) card (16 single- ended input channels) converted the signal (via a 12-bit monolithic converter) into binary code which could be processed by the host computer. Working with a range of -500 mV to +500 mV (1 Volt) an ORP resolution (change) of 1000 mV/212 = 0.25 mV 52 :  ( ^ ^ORP AAAA ; W W J ORP i Model of ORP Signal Source i V IN £ R > INPUT Input Model of the Amplifier V = Voltage of the ORP Source ORP R  O R p = Internal Resistance of the ORP Probe R lupin- = Input Impedance of the Amplifier I = Current V = The Voltage across the Amplifier = I R IN INPUT VORP = ' RORP + ' R INPUT " ' ( R ORP + R INPUT) * • " ' = Thus: V  = IN Thus: IFR ORP ( "ORP + R INPUT) ORP ' R  INPUTJ 'ORP INPUT > > > R ORP then V = V ^ INPUT + 1 (R ORP ORP INPUT' Figure 3.5 Impedance Diagram of ORP-Amplifier Circuit difference was obtainable. At various stages in the research, different computers were dedicated to the project; however, most of the preliminary work was performed on a Laser Turbo XT-2 computer operating at various times with a Central Point Software, Juko ST and finally Phoenix, BIOS on its motherboard. For the majority of the control runs a Morse 386-SX AT computer was used. To provide protection from brown-outs and power failures, an uninterruptible power supply (UPS) was purchased into which the computer and all power cords were plugged. When the input power line voltage dropped below an acceptable level (15 % below nominal), the UPS automatically transferred to battery operation (in less than 3 milliseconds) providing an output wave in the form of a sinewave approximation. During the course of this research, several momentary blackouts occurred and in all cases the UPS performed admirably and kept the process operating. For control purposes, a commercial I/O control card was purchased which fitted into an expansion slot in the computer's motherboard. The interface card provided 24 TTL/DTL compatible digital I/O lines, split into three 8 bit ports (Metrabyte Corporation, 1989). The I/O lines were linked to a bank of solid state relays (16) mounted on the inside of the box housing the computer. These, in turn, were wired to two socket power bars (mounted on the outside of the computer box) which were modified so that each outlet could be controlled independently by a single solid state relay. The pumps and solenoids were plugged into this latter bank of sockets and thus 54 control, originating from software switching bits (1 = ON, 0 = OFF), was finally established. 3.2.3 Computer Software The successful implementation of a computer controlled system is very much an "evolutionary" process. This is most evident in the development of the computer software. For example, the AASD*1 control software (Section 3.4.1), underwent 7 major structural modifications (not including numerous small adaptive measures taken to refine the program) before arriving at its "final version" form. The software was written using QUICKBASIC 4.5, a mature form of the original BASIC language developed at Dartmouth College over 25 years ago. Not only is it very popular (Shammas, 1988) , it is much more powerful than its earlier predecessors due to the advent of callable subroutines, numeric and alpha-numeric labels (used to direct program flow), and powerful new decision making constructs (Microsoft, 1987a, 1987b, 1987c). The lone exception to the QUICKBASIC 4.5 language was the software used to access the A/D board which was written for expediency in Microsoft Assembler Language by an in-house UBC computer technician. The prime advantage of QUICKBASIC 4.5 is that it can be written in a modular fashion. That is, a function or subroutine can be written, debugged and then installed as a separate module into any main program, written at various times and for different needs. Thus, the majority of subroutines and functions written for this research are common to both the AASD 55 experiments and the Bio-P experiments, with subtle differences reflected in the structural flow of the main control program and occasionally the order in which common subroutines are invoked. The Bio-P experiments also use separate controllers to operate some of the pumps and solenoids, in order to minimize the complexity of the main Bio-P control program. Table 3.2 catalogues the main control and subroutine/function modules incorporated into all three operating strategy programs. Flowcharts of all subroutines, functions and main control programs have been relegated to Appendix C, while the associated software code can be found in Appendix D. A detailed description of the mechanics of the program is not necessary here; however, some general comments are offered below. The structure of the main control programs (i.e. one for each AASD operating control strategy and one for the Bio-P experiment) is fairly sequential with the majority of control actions dictated by flag switches; these are set and reset to TRUE and FALSE respectively, in order to activate or deactivate specific relays. ORP data files are written to the hard disk with a nomenclature specifying the type of reactor (Fixed-Time (FT) or Real-Time (RT)) appended to the date (ex. 90-04-21.RT). Message files for both reactors coexist under an appropriately dated file (ex. 90-04-21.msg). Due to some initial incompatibilities between the software and hardware, the programs are designed to alternate between graphics and text mode, rather than operating in continuous graphics mode. Thus, the user can periodically 56 Table 3.2 Subroutines and Functions in Each Experiment Main Programs Functions Subroutines AASD*1 AASD*2 BIO-P Global.bi Typrobe$ Jinkey% Getscanl% Inform Filename Initrelays Relayswitch Refresh ORPscreen Axes Paxis Scans Diff Writing Transfer Plot Breakpt Layout Update 57 interact with the computer to graphically access recent historical plots of the ORP-time profile. When a plot is requested, the computer transfers the ORP data of the probe selected, to a common array, and after refreshing the screen, uses the PLOT subroutine to lay out the profile. The ORP probes are scanned by accessing the ON TIMER (Scantime) event-trapping Quickbasic 4.5 feature, which directs program flow (every number of seconds equal to Scantime) to a READPROBE subroutine which further invokes a function GETSCAN1%. After a certain number of scans have elapsed, the computer interrupts this loop to "drop" through the rest of the program where it calculates first-differences, writes data to disk files, checks flags according to externally-timed conditions, searches for the breakpoint (if in the appropriate phase of the cycle), and scans the keyboard buffer for user requests. The subroutine BREAKPT requires a more detailed explanation, since it is the cornerstone upon which control is based. BREAKPT operates as a "Linear Ring-Buffer", a term coined to describe the effect of a moving window along the slope of the ORP curve. BREAKPT is invoked when the computer registers (by way of a flag) that the air supply has ceased. After an initial delay to acquire stability (as air bleeds from the line) , the computer begins to load the first Ring (5 points wide) with ORP first-difference points (i.e. the first-difference or slope between two adjacent ORP values) until the Ring is complete. When the Ring is complete, an average of all five first- differences in the Ring is calculated and assigned to Ring(l) 58 which also receives the title "FirstRing" in the Ring-Buffer. (Note: The actual software variable names have the appropriate letter appendages, corresponding to the probe in question, ex. Ring2a(l) and FirstRing2A etc.) The next first difference point drawn into the Ring- Buffer (i.e. Pt 6) becomes the last point of (i.e. completes) Ring(2), while Ring(2)*s first point corresponds to the second point already in the Buffer. An average first-difference for Ring(2) is now calculated based on points 2 to 6. In other words each succeeding point is admitted into the Buffer to complete the Ring formed by abandoning the point occurring 6 points earlier. Finally, the terminal Ring in the Ring-Buffer (Ring(5)) is reached and is assigned the title "LastRing" (Figure 3.6). The value of LastRing is then compared to FirstRing and if it is substantially more negative (in this case DELTA is set to -1.25) the breakpoint is assumed to have occurred. The slope difference limit is somewhat arbitrary and is a function of the probe responsiveness. Preliminary testing, consisting of alternately tightening and loosening the knee constraint, indicated that a value of -1.25 for all probes was sufficient to detect the knee in the majority of cases (Figure 3.7). In the event that the slope change between LastRing (Ring(5)) and FirstRing (Ring(l)) is less than DELTA (i.e. more positive), the entire Ring-Buffer shifts, with the next first- difference point flowing in to complete Ring(6) (which now becomes LastRing). Concurrently, Ring(2) now receives the title FirstRing. The new slope difference is calculated and compared RING-BUFFER (1) Rlngl (FirstfHng) A = LastRing-Ftretfling >=-1.25 B B B B E B B.. RING -BUFFER (2) z t t t f t t t f t t t f t t t Differvies Pto 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Figure 3.6 Illustration of Unear Ring-Buffer Concept ORP IstOiffPts LastRing - Firstfllng >• / \ —1.25 (Knee is Trapped) 1 2 3 4 5 ORP istompts SLOPE AVERAGES OF 1ST DIFFERENCES PTS(1-5) PTS (2-6) PTS (3-7) PTS(4-8) PTS (5-9) Into Ring Number Rlngl Rlng2 Rlng3 Ring4 RlngS Ring Title Firstfllr LastRIn Figure 3.7 Illustration of BREAKPT Capture of Nitrate Knee to DELTA and again, if it is less (i.e. more positive), the Ring-Buffer continues to move in sequence. In this way, the Ring-Buffer functions as a moving window across the ORP profile until the knee is trapped by a difference in slope greater than DELTA (Figure 3.7). It should be noted that there is a requirement that only two of the three probes detect a knee in order for control to be initiated. This serves as a protective measure should one probe suddenly become inoperative. It also permits the withdrawal (and disconnection from the amplifier) of one probe for cleaning purposes. Experience has shown that it is best to withdraw the probe during the aerobic portion of the cycle, since the computer during this time is merely recording values, rather than actively searching for a control-based feature. Moreover, reinsertion allows some time for the probe to acclimate to reactor conditions before measurements again become critical for control purposes. The program also utilizes global variables in an INCLUDE file, so that both the size of the ring (RINGSIZE, currently set to 5) , the width of the Ring-Buffer (NUMRINGS, currently set to 5) and the individual knee constraints (DELTA2A, DELTA2b, and DELTA2C, currently all set to -1.25) can be varied as a function of the operator experience with the ORP probes and the type of waste. Finally, should the knee not be detected for whatever reason (ex. all probes foul (become less responsive) to the point where the knee constraint becomes too severe) some intelligence in terms of a time-base is built into 61 the program to initiate air resupply (in the AASD experiments) or to initiate acetate additions (in the Bio-P experiments), in order to keep the process respiring. 3.3 Raw Feed Collection Procedures During the AASD set of experiments, the SBRs were operated in a semi-continuous mode, in the sense that they manually received feed in a batch manner (once/day). Thus, activated sludge was wasted diurnally from the pilot-plant aeration basin, by routing it to the sludge thickener, where after 20-30 minutes of gravity settling, the sludge blanket interface, (initially at a level of 100-110 litres (a function of the system SRT)) usually reached the 40-50 litre mark. The sludge was then drawn off by means of a control valve or pump and collected in a 4 litre milk container for transport to the UBC lab. Once there, it was allowed to gravity settle a second time where a visual inspection of the sludge consistency and settling characteristics, usually meant that about half the clarified supernatant would be decanted off and disposed of down the drain. By systematically adhering to this two stage thickening process, the raw feed sludge consistently had a MLSS concentration roughly 3 times the aerobic basin of the pilot plant. Furthermore, for the most part, the feed MLSS was greater than that in the laboratory reactors. After wasting an appropriate amount from the reactors (Section 3.4.1) the feed sludge was then added (after shaking to ensure a uniform MLSS concentration) into the top of the reactor to maintain a 62 constant reactor volume. The remaining feed sludge was stored in a Bell-Par Industries environment chamber held at a constant temperature of 4 °C. For the most part this volume was stored purely for contingency purposes should fresh feed from the pilot plant suddenly become unavailable. In the Biological Phosphorus (Bio-P) Removal experiments, raw sewage was obtained directly from the external equalization tanks located outside the pilot plant facility. After collection, it was transported in carboys to the lab to be stored at 4 °C, for up to a maximum of 12 days. 3.4 Operating Control Strategies 3.4.1 Aerobic-Anoxic Sludge Digestion *1 (AASD#1) As mentioned in Section 1.2, the main objective of this research was to demonstrate the potential ORP has to control sequencing batch reactor wastewater treatment systems. Thus, operating strategies were formulated both to demonstrate control and to evaluate the effectiveness of ORP as a process control parameter. The first such strategy involved aerobic-anoxic digestion of waste activated sludge. It was structured such that the Control Reactor (RCTR#1) was known as the Fixed-Time Control (FT) reactor, since the ON/OFF sequence was "fixed" at 3 hours of air-on and 3 hours of air-off. The ratio of air-on to air-off was arbitrary and other reasonable ratios consistent with the literature review comments (Section 2.3) could have been used. In contrast, the Experimental Reactor (RCTR*2) was 63 labelled as the Real-Time Control (RT) reactor, since the on/off sequence consisted of a 3 hour air-on period (as before) but a variable length of time for air-off, contingent upon detection of the nitrate breakpoint. Reactor *2 exhibited Real-Time behaviour in the sense that it operated in an instantaneous on- line self-adjusting fashion. The rationale for adopting this control strategy is that theoretically, the Real-Time Control reactor should provide better treatment (in terms of solids degradation) since the bacteria are always ensured a ready supply of highly efficient electron acceptors (be they oxygen or nitrate). Thus, the different sequences of the reactor allow for effective organic carbon removal, and alternating nitrification and denitrification. Both digesters were controlled on the basis of solids retention time (SRT), as this was convenient to use, has significant merits (Smith 1978), and can be related to solids loadings when variations in feed and digester TVSS are recorded as part of the daily solids inventory. Since the reactor volumes are constant (4.8 litres) and there is no recycle, the SRT equals the hydraulic retention time (HRT). The SRT chosen for the AASD#1 experimental runs (10 days) was admittedly on the low end of the scale (Metcalf and Eddy, (1979) recommends 10-20 days); however, a shorter SRT translates to a larger volume wasted according to the equation below. SRT = volume of digester (3.1) volume wasted per day On track-study sampling days, larger volumes were necessary in order to accurately track parameters (such as N0X and NH3) which theoretically range from 0 to 100 % of their full value, throughout the course of one aerobic-anoxic cycle (assuming complete nitrification-denitrification). Thus, with a 4.8 litre liquid volume and a 10 day SRT, 480 mL of sludge was wasted on a daily basis and in due compensation, 480 mL of feed sludge was added to keep the reactor volume constant. Other operational nuances included occasional scraping of the digester walls to return biomass accumulations to the system. Distilled water was also added on a sporadic basis to compensate for evaporative losses. Evaporation was not perceived to be a problem, as there was seldom an observable discrepancy between the liquid level in the reactors and the 4.8 litre reference mark on the cylinder walls. Prior to start-up, the digester solids concentration was increased significantly by wasting (after a brief settling period), a clarified volume of supernatant (low MLSS) equal to that required to keep a constant SRT. The feed sludge (with a relatively high MLSS) was then added to artificially increase the solids level in the reactors, in an attempt to more closely simulate field digester conditions (> 30,000 mg/L). Before each run, the reactors were drained, thoroughly cleaned and some of the tubing (most often the sampling ports and air supply lines) was replaced. The diffusing stones were also acid washed to remove accumulated microbial growth tending to blind off the air pores. The ORP probes were also cleaned as will be described in Section 3.5.4. The sludge from both reactors was then mixed, split into two, and reintroduced into the reactors, so that both reactors ostensibly had identical starting conditions in terms of biomass characteristics and concentrations. Both reactors were then operated on a Fixed-Time basis for at least two days. If the ORP profile with time consistently produced the characteristic features described in Section 4.2.2. (i.e. In both reactors nitrate knees were present and dissolved oxygen levels during the plateau region of the ORP curve were between 2-4 mg/L (and roughly equivalent) ) , the decision to switch to Real-Time control of Reactor #2 was implemented. It must be noted however, that if the user requested real-time control, it was not until the next anoxic cycle that the computer switched over to this form of control. This circumvented the possibility that the user request could come during an anoxic sequence, in which the knee had already occurred. In order to assess the ability of ORP to effectively maintain control under duress, and to evaluate ORP as a process control parameter, perturbations to the operating strategies were investigated. The first and most natural disturbance to the system involved interrupting the daily wastage and feed pattern, simulating a breakdown in supply (i.e. the waste pumps from the aeration basin). As available carbon for the denitrification reaction was exhausted, the time necessary to complete denitrification became elongated; thus, this strategy sought to demonstrate the flexibility of control based upon actual rather 66 than fixed denitrification times. Other aggravations included additions of strong oxidants (hydrogen peroxide and sodium nitrate), and ammonia chloride spikes, all designed to observe the stability of ORP under transient influent conditions. After each disturbance a recovery time period was allotted to allow conditions to normalize. 3.4.2 Aerobic-Anoxic sludge Digestion *2 (AASD*2) Much of the preceding discussion is applicable to the second sludge digestion experiment. It should be noted however that AASD#2 was operated at an SRT of 20 days. The control reactor again operated in a Fixed-Time fashion (3 hours air-on, 3 hours air-off), a practice which can also be described as operating in a 50/50 air on/off manner. In contrast to AASD#1, the Real-Time reactor also operated in a 50/50 fashion, by matching its length of aeration period to the previous time for denitrification. In otherwords, the preceding cycle's total time to eliminate the nitrates (as calculated from the moment the air supply terminated, to the nitrate breakpoint (assuming near instantaneous disappearance of D.O.)) was recalled from memory and allocated to be the length for the following cycle's aeration period. In this way a 50/50 strategy was maintained. As mentioned in Chapter 1, it was suspected that an ORP-driven, 50/50 strategy might prove stressful for the organisms; in the sense that the strategy might collapse in on itself, with very rapid air on/off periods. However, if the bacteria seemed to readily accommodate this strategy, it might provide grounds for further investigating a control strategy which alternated extremely rapidly between denitrification and nitrification, as determined by the features on the ORP-time curve (Section 4.1). Such a strategy might induce considerably savings, through the discontinuing of overaeration during the nitrification portion of the curve. 3.4.3 Biological Phosphorus (Bio-F) Removal In Bio-P removal , the SBRs model in time the plug- flow treatment of a waste subjected to the right mix and sequence of aerobic, anoxic and anaerobic conditions. The operation of the two reactors differed in one aspect, that being, the timing for the addition to the reactor of volatile fatty acids (in this research acetate). The Fixed-Time reactor had the addition scheduled at 1 hour and 25 minutes (modelled after Comeau, 1989) into the anoxic period, while the Real-Time reactor had its timing triggered by the nitrate breakpoint. The SBR operation during the Bio-P experiments was somewhat more complex and thus commercially-purchased Chrontrol timers were used to initiate and control most of the sequences during the cycle. For both reactors, the period lengths (Table 3.3) were modelled after Comeau (1989), with each cycle having a total length of 8 hours. During the FILL phase (10 minutes), raw wastewater was pumped from an influent feed bucket to the reactor, where it underwent the first REACT (unaerated) period for 2 hours and 50 minutes. As indicated, approximately in the middle of the unaerated REACT period (after anoxic conditions had ended) acetate (30 mg per litre of raw influent) was pumped 68 Table 3.3 Timing of Phases in a Bio-P SBR SBR PHASE FILL Period REACT (Unaerated) Anoxic Period Anaerobic Period REACT (Aerated) SETTLE Period DRAW/IDLE Period CONTROL ACTION TIME ON (Hrs:Min) Feed Pump (0:10) (2:50) (1:25) Acetate Pump (0:06) (1:19) Air Solenoids (4:00) Waste Pump (0:10) (1:00) Wastewater Mixers (Off) Effluent Solenoids (0:10) TIME DIAGRAM I t • i r • 1 T 1 • i 1 f ,— 0:00 o: iu *?-nn o.uu / ,uu — 7:50 8:00 69 for 6 minutes into the reactors. Subsequently, the following REACT (aerated) period lasted for 4 hours while the SETTLE period lasted for 1 hour and included a 10 minute DRAW/IDLE period. Wasting normally occurs during the DRAW period, however, since the sludge settled well below the half-way decanting port, it was not possible to waste at this time. Thus, once/day, in the middle of the REACT (aerated) period, mixed liquor was wasted to control the sludge retention time at 20 days (a typical SRT for Bio-P plants) . The practice of decanting one half of the reactor contents every 8 hours (i.e. clarified effluent only) made for a 16 hour hydraulic retention time. 3.5 Analytical and Sampling Techniques 3.5.1 General Procedures As mentioned previously, the volume for a particular test was deducted from the total volume wasted. In all cases before extracting a sample, the sampling port was opened and allowed to run briefly, clearing the line of residual material not fully exposed to REACT conditions. This volume was returned to the reactor before reopening the port to obtain a representative sample. In addition, an appropriate volume of feed sludge or sewage was set-aside and reserved for later analysis. Sampling, handling and preservation time before analysis was kept to a minimum, with the majority of tests conducted in accordance with Standard Methods, 15th Edition 70 (A.P.H.A. et al., 1980). Exceptions and non-standard testing procedures are discussed in the following sections. 3.5.2 Suspended Solids Measurements Due to the elevated concentration of suspended solids in both the AASD digesters and feed sludge (>5000 mg/L), the Gooch crucible method of solids determination was deemed impractical, as discussed by Anderson (1989). Instead, daily solids were determined by taking duplicate 25 mL aliquots of well mixed sludge or feed (measured in a graduated cylinder) and transferring them to 50 mL centrifuge tubes. These were then spun down at 2500 rpm in an IEC Clinical Centrifuge until solids capture was judged complete (about 10 minutes). The supernatant fraction was vacuum-filtered through a previously tare-weighted, Whatman 934AH glass microfibre filter (5.5 cm diameter), which had been removed from its aluminium storage dish. The sludge residual at the bottom of the centrifuge tube was then scraped out and washed on to the filter paper. The aluminium dish (with the filter paper replaced inside) was then transferred to a Fisher Isotemp forced draft oven (Model 350) , operating at a constant temperature of 104 °C, where it was left to dry overnight. Reweighing with a Mettler AC 100-S2 balance allowed calculation of the Total Suspended Solids (TSS) concentrations, with an average of the duplicate samples assumed to be representative. Total Volatile Suspended Solids (TVSS) was determined by weighing the cooled residue remaining after igniting the dish to 550 °C (for one hour) in a Lindberg muffle furnace (Type 51828). 71 3.5.3 pH, Alkalinity, Dissolved Oxygen and Temperature All pH measurements used a Beckman $ 44 pH meter with automatic temperature compensation (ATC). Several different probes were used throughout the research; however, the meter was routinely calibrated using twin standard buffers (4.0 and 7.0 or 7.0 and 10.0) before being placed into 25 mL of unfiltered reactor and feed samples. Temperature measurements were made with a mercury thermometer. When dissolved oxygen readings were of interest a Yellow Springs Instrument (YSI) DO meter (model 54ARC) was used in combination with a YSI 5739 submersible probe. The membrane was changed on a regular basis to ensure effective D.O. transfer across the membrane. Samples for total alkalinity were titrated to an end point of pH of 4.5 with 0.02 N H2S04 acid. 3.5.4 ORP Measurements In keeping with the focus of this research, ORP measurements were recorded continuously using the probes described in Section 3.2.1. Probe responsiveness was tested prior to each run by immersion in a quinhydrone solution. Quinhydrone, an organic acid, sets up a well-defined equilibrium potential particular to a given pH and temperature. Accordingly, 2 grams of quinhydrone were dissolved into 200 mL of pH = 4 and pH = 7 buffer solutions (ASTM (1983)) and each probe in turn was inserted into the solution. At a pH = 4 (T = 18 °C) , an ORP probe (with a Ag/AgCl reference electrode) is expected to yield an ORP measurement of 270 72 millivolts. The corresponding value for a pH = 7 solution is 92 millivolts. In all cases, the ORP probes responded to within 5 to 20 millivolts of the expected value, although with varying degrees of speed (usually 2-15 minutes). During this research it was seldom necessary to resort to some of the harsher cleaning methods described in the American Society for Testing Materials (ASTM) handbook. The relatively clean waste and the frequency of aerobic conditions seemed to prohibit the build-up of slime films on the platinum ring which sometimes impede the rate of electron transfer across the surface. Normally all that was necessary was a distilled water rinse followed by a perfunctory wipe with a kleenex tissue. If visual discoloration of the noble metal persisted, the probes were dipped into either a dilute HCl or chromic acid ( 1 g K2Cr207 in 100 mL of concentrated H2S04) cleaning solution, as recommended by the ASTM. In some probes there was a slow movement of microbial growth (resembling a wetting front) up the ceramic porous plug which could have possibly reduced the ion transfer necessary to maintain electroneutrality. As this plug could not be physically accessed for cleaning, no remedial action was taken. 3.5.5 Nitrogen Analysis Nitrate and ammonia samples were first filtered through Whatman No. 4 filters prior to analysis. Nitrate was analyzed in triplicate by the colorimetric automated cadmium reduction method (A.P.H.A., 1980), using a Technicon AutoAnalyzer II Continuous Flow Analytical System (Industrial Method No. 100-70W). The cadmium granules advocated in this method were replaced with a cadmium wire. The strip chart recorder peak heights were compared with the heights from a series of standards of known concentrations. Ammonia Nitrogen was measured using the automated phenate method, with the intensity of the colour complex formed, determined by Industrial Method No. 98-70W on the AutoAnalyzer II. Total Kjeldahl Nitrogen (TKN) (in the AASD experiments) was determined by digesting 2 mL of the sample (and an appropriate volume of the standard) on a BD-40 block digester (in the presence of concentrated H2S04 and K2S04) in order to liberate all organically bound nitrogen. Samples and standards were then analyzed colorimetrically in triplicate on the AutoAnalyzer II (Technicon Industrial Method No. 376-75W). Percent N in the Bio-P experiments was measured exactly the same way except, instead of a liquid sample, approximately .025 grams of dried solids sample was used. 3.5.6 Phosphorus Analysis Ortho-phosphate (in the form of PÔ ,"3* was determined on filtered samples using the automated ascorbic acid reduction method (Technicon Industrial Method No. 327-74W). In this method, ammonium molybdate and potassium antimonyl tartrate react with orthophosphate, to form an antimony-phosphomolybdate complex which yields an intense blue colour suitable for photometric measurement after reduction with ascorbic acid. Samples for total Phosphorus (TP) and/or % P were 74 prepared and measured in the same way as TKN, with digestion on the block liberating all organically bound phosphorus. During the process, liberated phosphorus is oxidized to orthophosphate, the concentration of which can be determined by comparison to peak heights of known standards in the automated ascorbic acid reduction method described above. 3.5.7 Estimates of Carbon Content In order to characterize the sludge (i.e. determine a C:N:P: ratio) particulate samples for COD analysis were analyzed using the dichromate reflux method outlined in Standard Methods (A.P.H.A., 1980). Fifty mL of the sludge was diluted to 500 mL (i.e. a 1/10 dilution) with 10 mL duplicate volumes withdrawn by wide mouth pipette and transferred to the reflux flasks. Total Organic Carbon (TOC) was performed on the soluble fraction of the sludge using a 10 mL sample volume. The samples were run automatically on a Shimadzu Total Organic Carbon Analyzer (Model TOC-500) using a series of low and high standards. Combustion of the sample resulted in the production of a quantity of C02 proportionately equal to the amount of carbon in the sample. 3.6. Sample Preservation and Storage Techniques Whenever possible, samples were analyzed promptly after collection and preparation. Table 3.4 summarizes sample preservation and storage techniques when expediency dictated later analysis. 75 Table 3.4 Sample Preservation, Analysis and Detection Limits Chemical Parameter COD TOC NOx-N NH3-N TKN %N TP %P Ortho-P Sample Volume Preservative Storage Period 50 mL Frozen Indefinite 10 mL Frozen Indefinite 3 mL Phenol Mercuric Acetate 3 weeks @ 4°C 3 mL Cone. H2S04 3 weeks @ 4°C 3 mL (TKN) 0.025 g (%N) Cone. H2S04 3 weeks @ 4°C 3 mL (TP) 0.025 g (%P) Cone. H2S04 3 weeks @ 4°C 3 mL Phenol Mercuric Acetate 3 weeks @ 4°C Analyzed by Dichromate Reflux Method Shimadzu TOC-500 Autoanalyzer Colorimetric Automated Cadmium Reduction Autoanalyzer Colorimetric Method Autoanalyzer Colorimetric Method Autoanalyzer Colorimetric Method Autoanalyzer Colorimetric Ascorbic Acid Reduction 76 3.7 Statistical Techniques Averages, standard deviations, maximum and minimum values were calculated using the software program Symphony (release 1.2) of Lotus Development Corporation (Cambridge MA). 77 CHAPTER 4 AEROBIC-ANOXIC SLUDGE DIGESTION EXPERIMENTS 4.1 Review of Special Features of ORP Curves Before highlighting some of the mechanical and biological nuances particular to this research, it is necessary to describe in greater detail, the expected shape of an ORP-time profile, generated when activated sludge is subjected to alternating aerobic-anoxic conditions. Although the main feature of interest is the nitrate breakpoint (or knee (which it superficially resembles)), several other distinctive features exist, some of which may offer potential for control in later research. Since other investigators (Peddie et al., 1988, Jenkins and Mavinic, 1989b) have described these features in detail, only a brief review is presented here. Figure 4.1 displays the classical form of an ORP-time curve produced from an AASD reactor experiencing Fixed-Time conditions (3 hours of air-on, 3 hours of air-off). It can be seen that the ORP probe responds to the influx of oxygen by rising rapidly (as air is supplied to the reactor), even though the dissolved oxygen curve (the dotted line) shows no measurable response. During this initial period it is presumed that oxygen is being consumed (as soon as it becomes available) by nitrifiers, oxidizing the ammonia built-up from the previous anoxic portion of the cycle. This is shown by a decrease in NH3 (diamond marker) and an attendant increase in the nitrate concentration (triangular marker). Once the majority of this reserve has been transformed to ORP Plateau MLVSS/MLSS = 5188/6500 = 0.80; pH = 6.86 _2 a \ Dissolved Oxygen "Breakpoint" ^ (Point of D.O. Breakthrough) Elbow" 3 Hours of Air On ORP1b(mV/30) NOx-N (mg/L) TKN (mg/L) NH3-N (mg/L) D.O. (mg/L) Nitrate "Breakpoint" "Knee" 3 Hours of Air Off 15 i 17 Time (Hours) Figure 4.1 Fixed-Time ORP Profile Under AASD Conditions nitrates, the oxygen "breaks through" and becomes residual oxygen, measurable by a dissolved oxygen probe (the sudden jump in the dashed (D.O.) line). The ORP-time curve follows suit, making a sudden bend which due to its angular shape, is colloquially known as the "elbow" since it is reminiscent of the human equivalent. It is not yet clear whether this inflection point/elbow actually corresponds to a concentration of zero NH3 or rather a point where the oxidation of NH3 by 02 is at equilibrium (in balance with) the production of NH3 through hydrolysis of organic nitrogen. The latter explanation seems more likely since the NH3 seems to be "levelling out" at some minimum (plateau) value, which may mean that beyond this inflection point, as fast as it is produced by hydrolysis, it is being converted into nitrates. It can be seen that the nitrate concentration continues to increase beyond this point for the remainder of the aeration period. Eventually the ORP probe mimics the D.O. response, by reaching a plateau value, seemingly a function of numerous variables such as probe sensitivity, the rate of airflow and the biological dynamics involved. This plateau reflects an equilibrium relationship between the rate of air supply and the rate of air utilization by the biomass; again however, the specifics are not well understood at the present time. Upon cessation of air and as free oxygen is quickly exhausted from the system, there comes a time when those bacteria whom are able to, switch over and use nitrates as a terminal electron acceptor in the electron transport chain. Some 80 of the researchers mentioned previously have documented an inflection point related to the disappearance of oxygen; however, this has never been definitively observed during this research. As nitrate respiration continues and the nitrate concentration declines, eventually the point of zero nitrate concentration (the inflection point in the ORP-time curve) is reached. As mentioned this point is known as the "nitrate knee" and it is this feature which is the focus of this research. Beyond this, as more negative potentials are established, a corresponding "anaerobic plateau" begins to develop and presumably it is here that less efficient solids degradation processes (such as sulfate reduction, methane production and fermentation) predominate. Sampling at the very limit of anaerobiosis however (2 hours and 45 minutes of air off) yielded no production of sulfides. Moreover, even in the feed sludge which may have been stored for up to 8 hours, no measurable sulfides (detection limit of 0.1 ppm) were detected. It would seem that insufficient time is available for any anaerobic organisms (that managed to survive the aerobic phase of the cycle), to develop into a significant population. Thus, after the nitrate breakpoint, in theory, very little if any solids degradation is occurring because of the lack of highly efficient electron acceptors and the failure of other organisms to establish a significant presence. For comparative purposes, Figure 4.2 portrays an ORP-time profile indigenous to the Real-Time Control (RT) reactor (3 81 D) E x O « 5 - 4 - 3 - 2 - 1 O* CO > E, a. rr O -1 - -2 - MLVSS/MLSS = 4980/6328 = 0.79 pH = 6.88 Air Off after 3 hrs of Aeration Feed ORP2c (mV/30) o NH3-N (mg/L) + TKN (mg/L) A NOx-N (mg/L) 10 Nitrate Breakpoint as Nitrate Concentration Reaches Zero - Air On 12 Time (Hrs) 14 16 Figure 4.2 Real-Time ORP Profile Under AASD*1 Conditions 82 hours of air-on, a variable length of time for the air-off) . Again, clearly evident is the intersection between the ORP knee and the point of zero nitrate concentration. Consistent with the objectives of the Real-Time operating strategy, the profile does not proceed beyond this point; instead, it rises rapidly, as the ORP probe responds to the presence of oxygen immediately available after the computer detects the breakpoint and re- initiates the air supply. Figure 4.2 shows a sharp drop in the ORP value (at approximately 2:30 pm) corresponding to the input of daily feed. Due to the daily mechanics involved in sludge collection, transport, and routine laboratory analyses, the feed sludge was frequently in a highly reduced state, at the time of feeding, as compared to the reactor contents. Thus, feeding in these circumstances was equivalent to suddenly increasing the concentration of reductants in the reactor, (an increase in the concentration of the reduced form of NAD*) . Depending upon the relative difference between the feed and reactor ORPs, an ORP drop of up to 100 mV (depending upon the probe sensitivity) could occur. Of course, as the feed experienced oxidization, the ORP would begin to return to its prior value. Since the addition of feed created the potential for a false knee to be induced in the Real-Time (RT) reactor curve, the practice of feeding the Real-Time reactor approximately half-way through the aeration cycle (after the D.O. measurement) was adopted. However, the reactors would frequently be out of phase; therefore, it was quite possible that the Fixed-Time (FT) 84 160 a. O Feed to RT Reactor (Decrease In ORP) Feed to FT Reactor (Increase In ORP) Time (Hrs) Figure 4.3 Effect of Relatively Fresh Feed on Reactor ORP Curves : Air-On Discontinuity D.O. Breakpoint > E. Q. DC O First-Difference Curve ' Air-Off Discontinuity Nitrate Breakpoint Fixed-Time ORP Profile "T" 8 10 12 Time (Hrs) Figure 4.4 Overlay of First-Difference and ORP-Time Profiles Activated Sludge Acclimitization of Biomass to Air Supply and Solids Loading ORP Probes Discolouration of and Deposits on the Platinum Ring Fouling/Plugging of the Porous Junction Induced Currents in the Connecting Wires Amplifier _I_ Junction Box And Electrical Connecting Cables r Computer Hardware 1 Computer Software • Accessories Unshielded Wire Inside the Amplifier Floating/Differential Input Connectors Amps Blown by High Voltage Surges Connecting Pins Wired to the Wrong Ground Ground Loops Formed by Electrical Wires Faulty Harddrive and Power Supply Faulty Chips on Three Different MotherBoards Faulty Relay Control Board Routine Debugging of Control Programs Incompatibilities with Quickbasic Version and Custom Built Relay Board under Extended Running Conditions Faulty Air Solenoid Connectors between Mixing Shafts and Motors Ill-Designed Loose Ground Pin in Remote Power Bar Figure 4.5 Linear Diagram of Components Identifying Problem Areas 86 Many of the mechanical problems were isolated and remedied in a diagnostic fashion, by sequentially disconnecting the system elements and linking them in various and tandem combinations until identification of the offending component(s). It is worthwhile to mention that a large portion of the difficulty was surmounted, when the experiment was redesigned with adequate knowledge of proper grounding techniques. For example, during one phase, all electrical components were connected (and apparently functioning properly); however, the ORP probes behaved erratically when immersed in the reactor solutions, despite near perfect readings when submerged in quinhydrone test solutions. An oscilloscope detected a stray current travelling down the motor armature, through the mixing shafts and into the reactor solutions, thereby swamping any biologically-induced signals. To remedy this problem, teflon connecters were designed in order to isolate the motors from the mixing shafts/biological liquids. The existence of ground loops further complicated matters by producing an interaction effect between the two reactors, surfacing primarily when one reactor switched on (or off) an air solenoid. The effect manifested itself in the form of a sudden spike in the ORP profile of one reactor, when the air to the other reactor clicked on or off (and vice versa) . This became critical in the Real-Time control reactor, since if the spike conformed to a sudden drop in the ORP profile, it quite realistically simulated a nitrate breakpoint, thus causing the computer to prematurely initiate air resupply. Figure 4.6 87 -100 •120 -140 -160 -180 - -200 - -220 Interaction Effect Air On or Off to One Solenoid Causes a Spike In the Other ORP Curve ORP1a ORP2C ~r 4 8 12 Time (Hrs) 16 I 20 24 Figure 4.6 Reactor Interaction Effects Due to Improper Grounding 88 illustrates a typical example of the interaction effect between the two reactors. Many of the problems were trivial in nature but quite time consuming to detect. For example, a loose ground pin in an electrical socket on a remote power bar, produced an intermittent problem whereby the curve form would be smooth for a period of time (Figure 4.7) and then suddenly degenerate into electrical noise. Eventually this problem worsened to the point where the ORP curves resembled a seismograph waveform (Figure 4.8) . An even more time consuming problem was the suspected existence of an interaction effect between the Quickbasic 4.5 language itself and the custom-built relay control board originally installed in the computer. In this case, the computer would run perfectly, from anywhere from 2 to 9 days, before suddenly "locking up" to the extent of requiring a power-down/ power-up reboot of the system. The locked condition of the computer usually meant that one reactor received air overnight while the other reactor went unaerated, a condition presumed to be highly detrimental to bacterial cultures having a life-span of 20-30 minutes. Moreover, after such a disturbance, any serious comparison between the two reactors was highly questionable. The purchase of a commercial relay-control board solved this problem. Despite many such difficulties, only a few of which have been recounted here, it can be concluded that, provided sufficient attention to detail is observed, a robust design will 89 260 > E. fl- oe O Solenoid Clicks Off — 0RP2a 8 10 Time (Hrs) Figure 4.7 ORP Profile Affected by Intermittent Electrical Noise 270 260 H 210 -\ 200 H 190 ORP2b ~i r 4 "i i i i i 1 r 12 16 20 24 Time (Hrs) Figure 4.8 Complete Deterioration of ORP Profile eventually prevail. This attention to detail would be paramount in full-scale applications, where numerous electrical and other similar interferences would be commonplace readily negating any meaningful data monitoring and process control. 4.2.2 Experimental Pre-Run Conditions Once the hardware and software irregularities were eliminated, attention could be focused on the biological conditions in the reactor. "Adequate running conditions" could be obtained by harmonizing readily adjustable parameters, such as air supply and solids concentrations. In certain cases, this would take several days as the biological elements within the reactor became accustomed to the dynamic interplay between solids levels and air supply. Experimenting, until the right combination of these two parameters was achieved, led to the development of conditions deemed suitable for the commencement of an AASD run. These conditions consisted of "equivalency" in terms of ... (i) Both reactors operating on a Fixed-Time basis, (ii) The consistent occurrence of the characteristic curve shape of the ORP profile under Fixed-Time conditions (with all attendant features); (iii) A good range (at least -200 mV to +200 mV) between the minimum and maximum ORP values; and (iv) A D.O. measurement during the plateau portion of the cycle between 2 and 4 mg/L. Figures 4.9 and 4.10 consist of extreme examples of curves obtained during sporadic periods when the experiment I a. en o 91 Time (Hrs) Figure 4.9 Unusual Response Pattern: No Nitrate Breakpoint 40 30 - 20 - 10 > E, 0. <r O No D.O Breakpoint No ORP Plateau No Nitrate Breakpoint ORP2b Time (Hrs) Figure 4.10 Unusual Response Pattern: No Diss. Oxygen Breakpoint seemed to be mechanically sound but experiencing difficulties, as biological conditions inside the reactor adjusted to the balance between air supply and solids level. In the majority of cases, curves much less extreme were observed; however, whenever the micro-organisms were acclimating to pre-run conditions, the ORP curves took a few days to consistently arrive at all of the distinctive features of the "classic" ORP-time curve indigenous to Fixed-Time AASD conditions (Figure 4.1). Once "equivalency" was achieved, the command to "switch over" to Real-Time control was issued (Figure 4.11). From then on the air was activated in the Real-Time reactor by the breakpoint occurring in the anoxic cycle. 4.3 Behavioral Trends: AASD*1 Experimental Conditions 4.3.1 Operating Characteristics and ORP Profiles Several general observations can be made regarding the pattern of ORP curves generated during the first set of AASD experiments. Under this operating strategy, at least 4 cycles/day of aerobic-anoxic sequences (6 hours total for the air-on, air- off time period) occurred in the Fixed-Time reactor. The Real-Time reactor however would frequently be into its 5th cycle, since denitrification often occurred within 3 hours, making the total cycle length of the Real-Time reactor less than 6 hours. Over the course of a 24 hour period however, all probes in both reactors showed a remarkable consistency in the curve shape, from cycle to cycle as illustrated in Figure 4.12. As mentioned earlier, critics of ORP often decry the 93 160 Fixed-time Real-Time 120 - 80 - 40 - > o -40 - -80 - -120 -160 Drop in ORP Resulting From Feed ORP2c i 12 16 20 24 Time (Hrs) Figure 4.11 "Switch Over Day": FT to RT Control - AASD#1 94 180 24 Time (Hrs) Figure 4.12 Temporal Reproducibility of ORP Curves in RT Reactor fact that ORP probes in the same sewage, frequently yield widely divergent results. This research, however, emphasized the relative change in ORP with time, with Figure 4.13 illustrating that all 3 probes in the same reactor simultaneously detected the breakpoints, despite widely diverging absolute values. Minor discrepancies in detection times are ascribed to differences in the individual probe sensitivities. Moreover, the particular example selected is an extreme example of differences in the absolute ORP values and is presented solely for clarity of illustration with regard to detection times. In the vast majority of cases, the actual absolute difference between probes in the same reactor was less than 20 millivolts. The most distinctive characteristic evident in reactors operating under Real-Time AASD conditions, is the self- adjusting ability of the reactor to dynamically meet zero- nitrate effluent guidelines. This is due to the reactor's ability to delay switching on the air until denitrification is complete. On a 24 hour basis (after feeding which raises the carbon level in the reactor), the overall available carbon level decreases, necessitating longer and longer denitrif ication times (i.e. There is an increase in the total elapsed time between the cessation of air and the nitrate breakpoint). The advent of feeding on the following day immediately shortens the denitrification time and the sequence repeats itself. Operating the reactors in this way generates the cyclical pattern illustrated in Figure 4.14 and 4.15, with the length of the anoxic zone a reflection of the amount of carbon available in 96 180 I Q. o Time (Hrs) Figure 4.13 Spatial Reproducibility of 3 ORP Electrodes in Same Reactor 97 3.2 3 - i 2.8 2.6 g" 2.4 X •a o CD a. x o c < o c o OB i _ a 2.2 H 2 1.8 1.6 1.4 - 1.2 - 1 - 0.8 0.6 0.4 H 0.2 0 Point of Feed Addition Nov/Dec 24 25 26 27 28 29 Date 30 Figure 4.14 Anoxic-Zone-Length: Cyclical Pattern Due to Daily Feed J2 •o o 'u. CD 0 _ o 'x o c < "5 c o o July 14 15 16 17 18 19 20 21 22 23 Date Figure 4.15 Anoxic Periods Greater Than the 3 Hour Fixed-Time Limit the system. Further to this, Figure 4.15 illustrates the power of this approach since, in this snapshot, many of the anoxic periods extend beyond the 3 hour anoxic-limit constraint (time available for denitrification) arbitrarily imposed upon the Fixed-Time reactor. Especially noticeable are the two days in which the feeding process was omitted. On these days, the dearth of carbon available for denitrification would result (if decanting had occurred) in a release to the environment (from the Fixed-Time reactor) of an effluent containing nitrates. Again, if a water body had as a priority a ban on nitrates, these instances would represent periods of non-compliance with the stated objectives. In contrast, it can be seen that the Real-Time reactor ensured that all the nitrates were eliminated before release of the effluent. 4.3.2 General Observations: Chemical Parameters Table 4.1 summarizes some selected chemical statistics of daily measurements performed on the Feed, Fixed- Time, and Real-Time reactors during AASD#1. A complete listing of chemical data for the entire 60 day run can be found in Appendix E. Since no effort was made to regulate the solids loading to the digesters (other than maintaining a reasonably consistent sludge collection procedure), the daily variation in feed solids concentrations was quite large and is reflected in the large standard deviation (Table 4.1) relative to the means (i.e Std. Dev. approximately 20 % of the mean value) of the TSS 99 Table 4.1 Selected List of Chemical Statistics: AASD#1 Chemical Parameter TSS (mg/L) VSS (mg/L) TKN (mg/L) NOX-N (mg/L) NH3-N (mg/L) TP (mg/L) Ortho-P (mg/L) Dissolved Oxygen (mg.L) pH Statistic Maximum Mean Minimum Std.Dev. Maximum Mean Minimum Std.Dev. Maximum Mean Minimum Std.Dev. Maximum Mean Minimum Std.Dev. Maximum Mean Minimum . Std.Dev. Maximum Mean Minimum Std.Dev. Maximum Mean Minimum Std.Dev. Maximum Mean Minimum Std.Dev. Maximum Mean Minimum Std.Dev. - FEED 13550 7841 5188 1626 10794 6174 4158 1306 953 546 331 111 7.68 1.89 0.13 2.05 16.60 3.00 0.06 4.27 472 306 164 64 31.70 8.40 0.00 9.27 7.30 6.79 6.37 0.20 Fixed-Time Reactor 7472 6569 5336 600 5812 5080 4154 442 493 436 265 47 4.66 1.64 0.08 0.86 0.99 0.23 0.04 0.29 385 300 164 49 61.54 45.85 23.82 7.59 5.30 3.20 1.40 0.93 7.36 6.76 6.37 0.22 Real-Time Reactor 7404 6511 5288 610 5712 5005 4116 432 500 428 323 44 4.18 1.80 0.04 0.73 0.92 0.16 0.07 0.18 385 302 199 53 56.23 42.39 25.00 6.79 5.20 3.31 1.40 0.88 7.39 6.77 6.39 0.21 and VSS feed solids. It can also be seen that the feed solids concentration (both TSS and VSS) was approximately 1000 mg/L greater on average than the reactor solids levels. Less variation was expected in the reactor solids concentrations (Std. Dev. approximately 9 % of the mean). The different extent of these variations are shown in Figure 4.16. It is noted that full-scale digesters operate at much greater solids concentrations (approx. 3 % solids). The pilot plant facility however, is not able to produce this level of solids as influent feed to the laboratory digesters. The average ratios of VSS/TSS were 0.79, 0.77, and 0.77 for the Feed, FT, and RT reactors, respectively. The relatively constant nature of all of these ratios is illustrated by parallel plots of VSS and TSS for the feed sludge only (Figure 4.17). The speciation of nitrogen forms (TKN, NH3, and N0X) is very much a function of the sampling time (i.e whether the air is on or off); thus, the standard deviations (Table 4.1) for both the NH3 and N0X are quite large. Since the TKN parameter is almost all organic nitrogen, its variation is much less. Figures 4.18 and 4.19 show the profiles with time of total nitrogen and total phosphorus. The feed nitrogen content fluctuated in accordance with the influent solids concentration; however, inside the reactors, the total nitrogen remained relatively constant. As nitrogen was removed from the system, it should have showed a gradual decrease over the course of digestion. It is suspected that experimental error masked this trend and therefore more precise laboratory techniques (such as 101 14 13 12 11 10 9 J S" 8 ™ S E.S 7 ^ 3 5 4 3 2 - 1 - Feed Solids Concentration Ommission of Daily Feed (2 Days) FT and RT Solids Concentrations • Feed 4- FT Reactor 0 RT Reactor r « - 60 0 20 40 Time (Days) Figure 4.16 Daily Variation in Feed and Reactor TSS: AASD#1 Ommission of Daily Feed (2 Days) a » 20 ~r~ 40 60 Time (Days) Figure 4.17 Parallel Plot: Feed Sludge AASD#1 TSS/VSS Ratio 102 E. O t c <D O) o 1000 900 - • Feed + Rxed-Time o Real-Time 800 700 - 600 - 500 - _ 400 2 o I- 300 200 2 Days Missed Feed 60 0 20 40 Time (Days) Figure 4.18 Fluctuations in Total Nitrogen Content: AASD#1 E. ST b. tn w O sz a. co o sz a. "ja o 480 460 440 -j + 420 - 400 - 380 - 360 - 340 320 H 300 280 - 260 - 240 - 220 - 200 180 -\ 160 Feed Rxed-Time Real-Time 2 Days Missed Feed 20 - T — 40 60 Time (Days) Figure 4.19 Fluctuations in Total Phosphorus Content: AASD#1 pipetted dilutions) were implemented for subsequent runs. The total phosphorus experienced an increase during the first half of the run, while subsequently levelling off during the latter portion of the run. It is not known why this occurred but it is suspected that the initial rising trend in the influent TP values slowly forced the reactor TP levels to follow suit (since the reactor values represent a trade-off between the relative difference between feed and wastage values). With regards to soluble phosphorus, the variation in influent ortho-P was directly related to the freshness of feed. If routine operations dictated that the sludge be stored for several hours before being utilized as feed, then anaerobic conditions would prevail, releasing phosphorus into the bulk liquid. Thus, the standard deviation for the influent ortho-P was greater than 100% of the mean. On a cyclical basis, however, inside the reactor, the alternating aerobic-anoxic conditions would have caused an uptake followed by a release of phosphorus to the liquid. Due to an oversight, this trend was not verified. Total CODs were done on all sludges for the first 20 days. When coupled with daily TKN (minus the ammonia) and TP (minus the ortho-P) measurements, average C:N:P ratios for the sludges could be estimated. They were calculated to be 100:5.1:2.7, 100:5.4:3.4, and 100:5.3:3.4 for the Feed, FT and RT sludges, respectively. In all cases, the ratios were slightly larger than the conventional ratio (100:5:1, Metcalf and Eddy (1979)), especially for the nitrogen to phosphorus proportion. 104 This is consistent with the pilot plant's operation as a bio- nutrient removal plant, as the sludges were expected to have a higher proportion of nutrients, especially phosphorus. Sporadic measurements of soluble COD in the reactors revealed averages of 50 mg/L for the FT reactor, and 46 mg/L for the RT reactor, respectively. Both reactors had an average TOC concentration of 14 mg/L. The values for both these measurements are consistent with the sludge digestion process, as little soluble carbon was expected to be available, since the reactors operate with the primary source of carbon generated through endogenous metabolism. Carbon that does become available through cell lysis is immediately consumed by other bacteria. From the outset of this research, dissolved oxygen measurements were considered less important than ORP, due to reactor dynamics at the lab scale. In other words, it was quickly evident that providing identical airflow rates to the two reactors, often produced different D.O. levels in the bulk liquids. Several possible reasons include; (i) Irregular pore sizes in the diffusing stones; (ii) Disparate fouling rates of these pores; (iii) Possible slight discrepancies in the internal diameters of the air tubing; and (iv) Variations in the solids levels between the reactors. The above factors acted in concert to produce visually-discernable differences (in terms of bubble size) between the reactors. This translates directly into oxygen transfer efficiency. Furthermore, since bubble size control was beyond simple modifications to the experiment, it mitigated against using equal air flow rates to control air supply. Instead, air control was based upon preserving a relatively stable D.O. liquid level in the reactor (usually between 2 and 4 mg/L during the D.O. plateau portion of the cycle). As can be seen from Table 4.1, the relatively low standard deviation means that the majority of D.O. measurements fell within the required range. Routine pH monitoring was incorporated as a matter of principle since pH (acting as a "master variable") often provides the first indication of critical disturbances to a system. In AASD research, pH is especially important, since a prime reason for favouring aerobic-anoxic over continuous- aeration methods of treating sludge, is the fact that the consumption of approximately 7.2 mg/L of alkalinity (as CaC03) (Barnes and Bliss, (1983)), during the endogenous-respiration nitrification reaction ... C5H7N02 + 502 ==> 5C02 + NH3 + 2H20 (4.1) 2NH3 + 302 ==> 2N03" + 6H+ (4.2) H+ + HC03" ==> H2C03 (4.3) is balanced by alkalinity generated through denitrification reactions and reactions involving ammonification of organic nitrogen to NH3 (Warner et al., (1985)). Table 4.1 indicates that the pH of both reactors maintained a pH in and around the neutral range of 6.5 to 7.5. This is further shown by a plot of the daily variation in pH for the FT (Figure 4.20) and RT (Figure 4.21) reactors, respectively. There does seem to be a slight decrease with time in the pH of both reactors; however, the fairly small amount of fluctuations in the pH level indicate that the alkalinity produced during the anoxic portion of the cycle, was generally sufficient to balance the alkalinity consumed during the aerated portion of the cycle. As mentioned (Section 2.3), the absence of chemical additives to buffer pH is one of the more attractive cost-related features for considering aerobic-anoxic sludge digestion. If, however, the pH continued to decline, perhaps periodic chemical adjustments could be instituted. In this research, all experiments were conducted at a relatively constant room temperature of 22 °C + 1 °C. The impetus for this originates from the Nernst equation, which includes temperature in the denominator of the term preceding the logarithm. If temperature is held relatively constant, then in theory, a measurable change in the ORP potential can be directly attributed to a specific alteration in the ratio of oxidized to reduced species, rather than to a fluctuation in temperature. In practice, the feed sludge was usually slightly cooler than the reactor sludges; however, there was no discernable temperature drop. Thus a decrease in ORP could be ascribed definitively to a change in the ratio of the oxidized to reduced species (in this case the addition of the reducing feed). 107 X Q. 7.4 7.3 - 7.2 - 7.1 - 7 - 6.9 - 6.8 - 6.7 - 6.6 - 6.5 - 6.4 - 6.3 • Feed + FTRCTR i 20 40 60 Time (Days) Figure 4.20 Fixed-Time Reactor: pH vs. Time for AASD#1 x Q. 0 20 40 60 Time (Days) Figure 4.21 Real-Time Reactor: pH vs. Time for AASD#1 4.3.3 Mass Balances: Solids, Nitrogen and Phosphorus One method of comparing the performance of the two reactors is from a mass balance perspective (Figure 4.22). Both reactors were designed to reduce solids; therefore, since TSS and VSS measurements were made on a daily basis (for both digesters plus feed) any missing solids can be presumed to be degraded by bacterial processes. Similarly, nitrogen (TKN, N0X, NH3) was measured daily (with the nitrogen forms both expressed as nitrogen) ; thus, TKN and N0X were directly additive and were equal to the total nitrogen entering and exiting the system. Since the pH remained in the neutral range, it is assumed that no stripping of NH3 occurred and any missing nitrogen is lost solely as nitrogen gas. Phosphorus (TP, Ortho-P) was also measured daily; however, phosphorous should theoretically be conserved since there is no biological mechanism for its removal. Tables 4.2 and 4.3 summarize the results for each reactor based upon mass balances performed in two distinct manners. The actual calculations have been included in Appendix F. In the tables, the column entitled "Overall Mass Balance" refers to a summation period incorporating days 1 through 60, while the column entitled "Moving Average Balance" involves averaging the results from multiple balance periods, each equivalent in length to one 10-day SRT period (i.e. First SRT - Days 1-10, Second SRT - Days 2-11, etc.). As is evident in both tables, the two methods yield similar results for solids degradation (in terms of TSS and VSS) and nitrogen removal. The Cp = Concentration of Parameter in Feed Sludge Vp = Daily Volume of Feed Sludge Cg = Concentration of Parameter in Reactor VR= Volume of Reactor C = Concentration of Parameter in Waste V = Volume Wasted per Day A(C xV3= Change in Reactor Parameter Over Sampling Period (+) —> Increase ; (-) —> Decrease Feed Waste cF vF C W V W % Reduction = I[(CF)(VF)] X100 Figure 4.22 General Case of Mass-Balance Around Reactor (Adapted from Koers, (1979)) 110 Table 4.2 Mass Balances for Fixed-Time Reactor: AASD#1 Mass Balance Parameter Percent Reduced TSS VSS Total N Total P Moving Average Balance Wareham (1991) 14.7 % 16.8 % 17.5 % -6.5 % Moving Average Balance Jenkins et al. (1989a) 12.5 % 14.0 % Overall Mass Balance Wareham (1991) 15.8 % 17.7 % 17.9 % -6.2 % Overall Mass Balance Jenkins et al. (1989a) 14.6 % 12.5 % 1.4 % Table 4.3 Mass Balances for Real-Time Reactor: AASD#1 Mass Balance Parameter Percent Reduced TSS VSS Total N Total P Moving Average Balance Wareham (1991) 15.2 % 18.0 % 19.5 % -6.9 % Moving Average Balance Jenkins et al. (1989a) Overall Mass Balance Wareham (1991) 15.7 % 18.3 % 21.1 % -5.8 % Overall Mass Balance Jenkins et al. (1989a) relatively low percentage removals for both solids and nitrogen were not unexpected, since the reactors were operated at such a short SRT. For comparative purposes, the work of Jenkins and Mavinic (1989a) is also presented. In their study (comparing continuously aerated versus aerobic-anoxic digestion), one of the reactors was operated in a Fixed-Time fashion (albeit with a cycle partition of 2.5 hours air-on/3.5 hours air-off). The values quoted in Table 4.2 are those reported for the same SRT (10 days) and an equivalent temperature (2 0 °C) . It is apparent that the removals obtained for both solids and nitrogen in the AASD*1 experiments, compare well with the study by Jenkins and Mavinic (1989a), being a few percentage points higher for both solids and nitrogen. The phosphorus mass balance for this experiment recorded an apparent increase of 6 percent. The order of magnitude of this error is typical of the TP digestion technique used; since other researchers, (Jenkins (1988), Elefsiniotis (1992)) have reported similar difficulties with closing the phosphorus loop. It should be noted that the relatively small closing error that Jenkins and Mavinic (1989a) report for phosphorus, is more singular than characteristic of their results. As they acknowledge, all the phosphorus can be accounted for within experimental error, with a recovery range of 77-99 %. Thus, although one reactor closed within 1 % (co- incidentally it is the aerobic-anoxic reactor considered in this comparison), the range quoted also means that one reactor closed 112 within 23 percent. In fact, of the 18 phosphorus mass balances presented in the original research (Jenkins 1988), only seven (40 %) closed with less than 6 percent. Thus, an average of all phosphorus mass balances presented in their work reveals a phosphorus closing error of 8.6 percent. This latter number more closely aligns itself with the order-of-magnitude phosphorus error arrived at in this study. A comparison between Fixed-Time and Real-Time Control reactors indicates that both reactors performed essentially the same in terms of solids degradation (both TSS and VSS). Superficially, it seems that the Real-Time reactor performed slightly better in relation to nitrogen removal (up to 3 % using the overall mass balance method); however, the difference is not thought to be substantial enough to form any non-debatable conclusive statements. Thus, as a criteria to evaluate the overall performance of the two reactors, the mass balances associated with solids, nitrogen and phosphorous do not convincingly reveal a distinguishable difference between the two reactors. Instead, this method indicates that both reactors were comparable in terms of their removal efficiencies, with the Real-Time Control reactor perhaps (but not definitely) performing marginally better in terms of nitrogen removal. 4.3.4 Evaluation: Unsteady Process Input Conditions The second method of comparing the performance of the two reactors is to investigate the probe behaviour, when the reactor contents are subjected to transitory stresses. This 113 concurrently evaluates the suitability of the ORP probe as a control parameter. Accordingly, the reactors received (on a mass basis) "low" and "high" spikes of sodium nitrate, ammonium chloride and hydrogen peroxide in order to simulate unsteady process input conditions. Tables 4.4, 4.5 and 4.6 outline the timing and concentrations of the various spikes. Note that a "high" spike is defined as having 3 times the mass of chemical added as the "low" spike. Samples were removed from the reactors prior to, and immediately following the spikes, after allowing two to five minutes for adequate mixing and dispersion of the chemicals. Figures 4.23 through 4.28 show selected vignettes of the ORP response to the various spikes with some of the more pertinent statistics recorded on each figure. These figures can best be explained by tabulating for each reactor, the number of deviations (over the entire run) from the ideal curve shapes indigenous to the Fixed-Time (Figure 4.1) and Real-Time (Figure 4.2) control operating strategies. Deviations from the "norm" can then be classified as "failures", since in the majority of instances, they represent a failure to complete a biological reaction. For example, in this run, 3 major categories of failures exist, most of which can be linked to chemical spikes. The first class refers to "Incomplete Denitrification" and occurs when there is no discernable nitrate breakpoint in the ORP-time profile. No nitrate breakpoint means that insufficient time existed for the micro-organisms to fully eliminate the 114 Table 4.4 Particulars of Sodium Nitrate Spikes: AASD*1 Reactor Date Day Number Sampled Nitrate Air On (Hr:Min) Concentration Time of Spike Amount2 Sampling Time Concentration1 FT July/11/90 23 3:10 pm 2:05 2.02 mg/L 3:25 pm 43.2 mg 3:30 pm 4.09 mg/L RT July/11/90 23 5:10 pm 1:30 1.50 mg/L 5:10 pm 43.2 mg 5:15 pm 3.46 mg/L FT Aug/6/90 49 1:20 pm 1:35 1.68 mg/L 1:20 pm 129.6 mg 1:25 pm 7.02 mg/L RT Aug/6/90 49 10:00 am 1:30 2.34 mg/L 10:10 am 129.6 mg 10:15 am 8.09 mg/L 'Concentrat ion i s measured as N03-N mg/L 2Amount i s on a weight b a s i s as Sodium N i t r a t e Table 4.5 Particulars of Ammonium Chloride Spikes: AASD#1 Reactor Date Day Number Sampled Ammonia Air Off(Hr:Minl Concentration Time of Spike Amount2 Sampling Time Concentration1 FT July/13/90 25 5:20 pm 0:55 0.41 mg/L 5:25 pm 43.2 mg 5:30 pm 1.37 mg/L RT July/13/90 25 2:55 pm 0:55 0.39 mg/L 3:00 pm 43.2 mg 3:05 pm 1.27 mg/L FT Aug/9/90 52 4:35 pm 1:25 0.59 mg/L 4:40 pm 129.6 mg 4:45 pm 6.68 mg/L RT Aug/9/90 52 2:40 pm 1:25 0.56 mg/L 2:45 pm 129.6 mg 2:50 pm 6.43 mg/L Concen t r a t i on i s measured as NH3-N mg/L zAmount i s on a weight bas i s as Ammonium Chloride Table 4.6 Particulars of Hydrogen Peroxide Spikes: AASD*1 Reactor Date Day Number Sampled D.O. Air On(Hr:Mini Concentration1 Feed Sampled D.O. Air 0n(Hr:Min) Concentration' Time of Spike Amount2 Sampling Time Concentration1 FT Aug/12/90 55 2:00 pm 1:30 1.60 mg/L 2:50 pm 3:15 pm 2:45 0.75 mg/L 3:15 pm 1 mL 3:17 pm 3.80 mg/L RT Aug/12/90 55 3:10 pm 1:30 1.40 mg/L 3:40 pm 3:55 pm 2:15 0.80 mg/L 3:55 pm 1 mL 3:57 pm 3.70 mg/L FT Aug/15/90 58 2:15 pm 1:30 2.70 mg/L 2:25 pm 2:45 pm 2:00 1.50 mg/L 2:45 pm 3 mL 2:47 pm 10.6 mg/L RT Aug/15/90 58 3:10 pm 1:30 3.75 mg/L 3:15 pm 3:35 pm 1:55 2.20 mg/L 3:35 pm 3 mL 3:37 pm 10.8 mg/L Concentration measured as Dissolved Oxygen (mg/L) 2Amount is based on a volume of 3% weight/volume H202 115 o_ o 200 150 100 50 - -50 -100 -150 -200 -250 Fed @ 1:30 pm Spiked @ 1:20 pm: NQ-N Concentration Increased from 1.68 mg/L to 7.02 mg/L A Failures - Incomplete Denitrification 20 40 Time (Hrs) Figure 4.23 High Spike of Sodium Nitrate to FT Reactor: AASD#1 5? E, a. rr O -30 H •40 * Spiked @ 10:10 am; NCk-N Concentration Increased from 2.34 mgA to 8.09 mg/L A Failures - Incomplete Denitrification 20 40 Time (Hrs) Figure 4.24 High Spike of Sodium Nitrate to RT Reactor: AASD#1 116 200 150 100 - 50 - E. Q_ o -50 - -100 -150 -200 - -250 Fed @ 1:30 pm * Spiked @ 5:25 pm; NK-N Concentration Increased from 0.41 mg/L to 1.37 mg/L • Failures - Incomplete Oenrtrification 40 0 20 Time (Hrs) Figure 4.25 Low Spike of Ammonium Chloride to FT Reactor: AASD#1 E, a. •c O Time (Hrs) Figure 4.26 Low Spike of Ammonium Chloride to RT Reactor: AASD*1 117 250 200 - 150 - 100 - D.O. prior to Feed = 2.70 mg/L Fed @ 2:25 pm. s a. rr O 50 -50 - -100 - -150 -200 * Spiked @ 2:45 pm; Dissolved Oxygen increased from 1.50 mg/L to 10.60 mg/L 12 16 20 24 Time (Hrs) Figure 4.27 High Spike of Hydrogen Peroxide to FT Reactor: AASD#1 200 D.O. prior to Feed = 3.75 mg/L Fed® 3:15 pm -40 * Spiked @ 3:35 pm; Dissolved Oxygen Increased from 2.20 mg/L to 10.80 mg/L T 12 - r - 16 - r - 20 24 Time (Hrs) Figure 4.28 High Spike of Hydrogen Peroxide to RT Reactor: AASD*1 118 nitrates. These failures are characterized by the solid, triangular marks noted on the previous six figures. In Figures 4.23 and 4.24, the failures result from an elevated level of nitrate caused by the disassociation of sodium nitrate. In Figure 4.25, they are caused by the inability of the denitrifiers to eliminate the nitrates generated by nitrification of ammonia originally in the form of ammonium chloride. Note that the addition of a particular spike may cause failures in a number of subsequent cycles, as the reactor seeks to recover from the effect of the stress. The second category of failure is the converse of the above and is associated with "Incomplete Nitrification" as depicted in Figure 4.29 (solid rectangular mark). This failure, caused by elevated levels of ammonia in the system, is reflected in the absence of the dissolved oxygen breakpoint in the ORP- time curve. There is no "breakthrough" of oxygen because insufficient time exists for the nitrifiers to reduce the ammonia to a low enough level to allow free residual oxygen to become present. The final failure category (Figure 4.30), is particular to the Real-Time reactor alone and is a failure in the more conventional sense, since the software "failed" by detecting a false nitrate knee (Figure 4.30, solid circular mark). Daily fluctuations in the air supply rate and solids loading, sometimes resulted in excess air entering the system relative to the mass of solids present in the reactor. The resulting over-oxidation of the sludge was reflected in the slow 119 200 150 - 100 - 50 - E Q_ rr O -50 - -100 - -150 -200 F e d ® 1:50 pm * Diss. Ox. Breakpoint "Qbow"asD.O. Breaks Through Fed @ 2:20 pm * Spiked @ 4:40 pm; NHg-N Concentration Increased From 0.59 mg/L to 6.68 mg/L • Failure - Incomplete Nitrification A Failure - Incomplete Denitrification FT Reactor: "High* Ammonia Spike 20 40 Time (Hrs) Figure 4.29 Typical "Incomplete Nitrification Failure" E CL rr O Fed @ 10:30 am • Failure - Detection of False Breakpoint "Knee* Initiates Air Supply Prematurely 12 Time (Hrs) Figure 4.30 "False-Knee" Failure In Real-Time ORP Profile rate at which the ORP value declined, after the air supply was halted. If the rate was excessively slow, the MAXAVOID window (the variable used to delay the search for the breakpoint until air had bled from the line and stability had been achieved) was in essence, prematurely "used up" by little, if any, changes in the ORP value with time. This was especially common if the probe was dirty and/or unresponsive. Thus, by the time the true decline began, the RingBuffer was often partially filled with horizontal (i.e. zero ORP slope change) values. The sudden change, as the true descent commenced (i.e the reactor truly entered anoxic conditions), sometimes was sufficiently steep enough to exceed the DELTA limit, (registering a knee-like feature) and triggering the air solenoid. It is evident that there are several ways to remedy this problem, most notably the mechanical methods such as cleaning the probes, attempting to better match the air supply to the solids loading (reduce the air/solids ratio) or deliberately thickening the feed sludge so that the ORP curve declines more rapidly (increasing the solids/air ratio). Controlling the air supply is at the best of times difficult at the lab scale, while increasing the solids loading is somewhat artificial and may not always be possible. Thus, these two methods were not seriously considered. Furthermore, cleaning the probes produced intermittent success depending on how much the fouling actually contributed to the lack of decline in the ORP curve. The other two ways of reducing these types of failures were software-based and involved tightening the knee constraint and/or expanding the window capacity of the variable MAXAVOID. Of the two options, expanding MAXAVOID represented a more certain means of success, since tightening the knee constraint would ideally involve some experimental trials, being a reactive rather than a proactive method of eliminating the problem. Currently, the program is not flexible enough to interactively shorten the length of the MAXAVOID window; however, the program was quickly recompiled (after the window was expanded from 16 to 30 minutes) and this eliminated the problem. Regardless of the solution chosen, it is clear that these types of failures could be reduced or even circumvented with more sophisticated programming techniques and/or better detection algorithms. In terms of some general comments, it is noted that "Incomplete Denitrification" was by far the most common failure. It is also evident that the hydrogen peroxide spikes produced no failures of any kind. Other stresses included the addition of "stale" feed which referred to a period of two consecutive days in which the same sludge was used to feed the reactors thus allowing NH3 in the feed to build-up through hydrolysis of organic nitrogen. With regards to the period in which the feeding process was omitted (already alluded to in Figure 4.15), Figures 4.31 and 4.32 show the FT and RT reactor responses to this type of stress. The Fixed-Time reactor logged four "Incomplete Denitrification" failures, while the Real-Time 200 150 - 100 - 50 - > Q. o -50 -100 - -150 - •200 122 0 20 40 60 July/19/90 Juiy/20/90 July/22/90 Time (hrs) Figure 4.31 Fixed-Time Reactor Response to Missed Feed: AASD#1 180 -60 0RP2C Feed Missed Feed - July/19-21/90 RT Profile 0 20 40 60 July/19/90 July/20/90 July/21/90 Time (hrs) Figure 4.32 Real-Time Reactor Response to Missed Feed: AASD#1 reactor because of its flexibility, easily accommodated this disturbance. Tables 4.7 and 4.8 summarize the number of occurrences, over the 60 day period, of each of the three categories of failures. The total number of cycles during the run was 231 for the Fixed-Time and 246 for the Real-Time Control reactors respectively. Thus, using the data from Tables 4.7 and 4.8, the Fixed-Time reactor failed 9.5 % of the time (22 failures) while the Real-Time reactor failed only 5.3 % of the time (13 failures). Furthermore as mentioned, many of the Real- Time reactor failures were software-based and could have been circumvented with more sophisticated detection algorithms. Thus, a comparative evaluation based upon a "failures" criteria, indicates that the Real-Time reactor outperformed the Fixed-Time reactor during AASD#1 by more readily accommodating and recovering from the stresses considered in this research. 4.4 Behaviourial Trends: AASD#2 Experimental Conditions 4.4.1 Operating Characteristics and ORP Profiles As mentioned in Section 3.4.2, the second AASD operating strategy consisted of comparing two reactors, both operating in a 50/50 air-on/air-off fashion. The Fixed-Time reactor retained its original ratio for each segment (i.e 3 hours for air-on, 3 hours for air-off); thus, there was a total of four, 6 hour cycles/day. Its characteristic profile was identical to that generated under AASD*1 operating conditions (i.e. Figure 4.1). Table 4.7 Failures Associated with FT Reactor Operation: AASD#1 Type of Stress Normal Operation Sodium Nitrate Spikes Ammonia Chloride Spikes Hydrogen Peroxide Soikes Ommission of Daily Feed Addition of Stale Feed Total Number of Failures Incomplete Denitrification Failure 3 4 7 0 4 2 20 Incomplete Nitrification Failure 1 0 1 0 0 0 2 False Nitrate Breakpoint Failure 0 0 0 0 0 0 0 Total Number 4 4 3 0 4 2 22 Table 4.8 Failures Associated with RT Reactor Operation: AASD#1 Type of Stress Normal Operation Sodium Nitrate Spikes Ammonia Chloride Spikes Hydrogen Peroxide Spikes Ommission of Daily Feed Addition of Stale Feed Total Number of Failures Incomplete Denitrification Failure 2 2 3 0 0 0 7 Incomplete Nitrification Failure 0 0 1 0 0 0 1 False Nitrate Breakpoint Failure 5 0 0 0 0 0 5 Total Number 7 2 4 0 0 0 i 13 1 The Real-Time reactor's operation consisted of matching the time for aeration to the previous anoxic period length, as determined by the detection of the nitrate knee. Figure 4.33 portrays the "switch-over" day from Fixed-Time to Real-Time conditions, and depicts the rapid development of a distinctive pattern, reflecting the tendency of the Real-Time reactor to "collapse" in on itself, with very short on/off times for both the aerated and non-aerated portions of the cycle. Consequently, as Figure 4.34 illustrates, the characteristic profile associated with AASD#2 Real-Time conditions, consists of a vastly reduced total cycle time, (very brief air-on and air- off sequences), with the shortest sequence immediately after feeding, followed by a gradual lengthening throughout the day. The fluctuations in the cycle length are better illustrated in Figures 4.35 and 4.36. These figures track the cycle over two days in which the feeding process was omitted. Figure 4.35 has 13 complete cycles, while the next day (Figure 4.36), is comprised of only 7 cycles. The expansion in the cycle length over the course of a day is directly attributable to a depletion in readily available carbon in the system. Concurrently, there is a gradual rise in the peak absolute ORP value associated with each cycle, and this is also due to exhaustion of carbon from the system. The short cycle time made it difficult to accurately distinguish the "classic" features of the ORP-time curve, thus some interpretation has been necessary for this analysis. Moreover, the brevity of the cycle time (after feeding), 240 Feed -20 -i -40 -#> - •so -I -100 0RP2b Fixed-Time " Real-Time -i 1 1 r i i r 8 12 16 Time (Hrs) 20 24 Figure 4.33 "Switch Over Day": FT to RT Control - AASD#2 127 Time (Hrs) Figure 4.34 Real-Time ORP Profile Under AASD#2 Conditions 128 70 -50 Missed Feed Day Nov/11/90 ORP2a T 4 8 12 16 20 24 Time (Hrs) Figure 4.35 RT Profile AASD#2 - Missed Feed Day Nov/11/90 > a. O •40 Missed Feed Day - Nov/12/90 0RP2a 12 16 20 24 Time(hrs) Figure 4.36 RT Profile AASD#2 - Missed Feed Day Nov/12/90 129 eventually led to a new software-based "failure" category, in which the program "failed" to locate the breakpoint, by actually physically "missing" the nitrate knee (Figure 4.37). This stands in contradistinction to the AASD#1 "False-Knee" failure in which the computer "failed" by detecting a non-existent knee, attributable to the excessively slow decline in the ORP-time curve. As Figure 4.37 illustrates, during the 6th cycle of the day, the steep gradient of the ORP-time curve means that the knee occurred almost immediately upon cessation of air . The computer therefore "missed" the knee entirely and the reactor proceeded into truly anaerobic conditions. After 4 hours, the "intelligence" built into the program reactivated the air supply, since the computer "assumed" the knee had been missed. Consequently, the next aeration period was also 4 hours as the computer adhered to its 50/50 operating strategy. Subsequent to this, the cycle lengths shortened once again, and eventually, a daily recursive pattern developed revolving around one "Missed- Knee" failure a day, with the occasional two such failures in a single day (Figure 4.38). The rationale for this failure is the reverse of that proposed for the "False-Knee" failures of AASD#1. The rapid decline in the ORP curve means that the MAXAVOID variable, (which ordinarily is used to delay the search for the knee), is in reality, comprised of points which should be entering the Ring-Buffer for purposes of detecting the nitrate breakpoint. By the time the Ring-Buffer actually starts filling, the breakpoint 130 - "Missed Knee Failure' Shortened Cycles ORP2b Oct/10/90 i 12 I 16 Time (Hrs) Figure 4.37 "Missed-Knee" Failure in Real-Time ORP Profile 131 -200 Failure Missed Knee" Failure 12 16 20 24 Time (Hrs) Figure 4.38 Two "Missed-Knee" Failures During Single Day has already occurred and consequently the computer cannot capture the knee. In order to reduce the number of "Missed-Knee" failures, the variable MAXAVOID was shortened from 30 minutes to 10 minutes (instead of lengthening it, as was done in AASD*1) . This remedy, however, was not entirely successful in eliminating all of the failures of this kind, since occasionally denitrification occurred extremely rapidly after cessation of air. Clearly evident however, from both figures, is the ability of the Real-Time reactor to rapidly recover from this kind of failure, in the sense of again developing the short-cycle pattern. 4.4.2 General Observations: Chemical Parameters The chemical parameters measured during AASD*1 were also recorded for AASD*2 and the data has been relegated to Appendix E with a summary table depicted in Table 4.9. It should be noted that the reactors were spiked with potassium cyanide (56 mg/L) on the third last day of the run (after sampling) ; thus, the reactor statistics (Table 4.9) do not include the final and penultimate days, since certain variables were unduly influenced by the KCN spike. For example, for both reactors, the ortho-P suddenly increased by approximately 20 mg/L as the cells lysed, while the dissolved oxygen level rose by approximately 3 mg/L, as the demand for oxygen declined. The majority of observations made about the AASD#1 chemical data set are equally applicable to the data obtained from AASD*2. For example, the stochastic nature of the influent feed TSS and VSS solids (as compared to the relatively stable Table 4.9 Selected List of Chemical Statistics: AASD*2 Chemical Parameter TSS (mg/L) VSS (mg/L) TKN (mg/L) NOx-N (mg/L) NH3-N (mg/L) TP (mg/L) Ortho-P (mg/L) Dissolved Oxygen (mg.L) Alkalinity (mg/L) (as CaC03) PH Statistic Maximum Mean Minimum Std.Dev. Maximum Mean Minimum Std.Dev. Maximum Mean Minimum Std.Dev. Maximum Mean Minimum Std.Dev. Maximum Mean Minimum Std.Dev. Maximum Mean Minimum Std.Dev. Maximum Mean Minimum Std.Dev. Maximum Mean Minimum Std.Dev. Maximum Mean Minimum Std.Dev. Maximum Mean Minimum Std.Dev. FEED 10610 6547 4040 1372 8466 5376 3362 1109 734 480 294 92 6.74 1.29 0.07 1.55 11.20 1.14 0.04 2.52 425 215 116 50 22.26 3.07 0.06 4.54 256 185 128 28 7.37 6.89 6.57 0.18 Fixed-Time Reactor 6772 6039 4904 362 5350 4826 4122 281 528 441 352 38 4.05 1.25 0.09 0.77 0.71 0.26 0.00 0.23 306 260 216 25 73.09 60.15 48.41 4.63 5.30 3.12 0.70 0.93 176 146 120 15 6.78 6.56 6.36 0.11 Real-Time Reactor 6820 5931 4942 470 5442 4748 3954 367 530 430 336 41 5.05 0.73 0.14 0.74 0.89 0.16 0.02 0.15 317 258 212 27 75.94 63.56 47.71 4.38 4.60 2.49 1.00 0.82 180 146 110 15 6.88 6.54 6.28 0.12 reactor values (Figure 4.39 and 4.40)), the constant and parallel nature of the VSS/TSS ratio (averages of 0.82, 0.79, and 0.80, for the Feed, Fixed-Time, and Real-Time reactors were calculated), and the speciation and behaviour of the nitrogen forms (as a function of the air being on or off) were all similar in nature to the AASD*1 run. The C:N:P ratios for the Feed, Fixed-Time and Real-Time sludges were 100:5.66:2.41, 100:5.69:2.50, and 100:5.61:2.48, and again the comments made in discussing the results from AASD*1 are equally valid here. Figures 4.41 and 4.42 show the profiles with time of total nitrogen, and total phosphorus. Inside the reactors, both parameters (nitrogen and phosphorus) show a decrease with time over the course of the digestion period. The TSS (and VSS by implication of its constant ratio) also exhibited this trend. The decline of the reactor solids and total nitrogen levels is logical in that there are biological mechanisms for removal of both parameters. Moreover, it is readily apparent from Figures 4.39 to 4.41 that the feed values for both solids and nitrogen are on the average consistently larger than the reactor values. This is also shown by the mean values quoted in Table 4.9. The relative difference between the means (i.e. the feed mean is greater than the reactor mean) is reflected by positive removals being calculated for both parameters (solids and nitrogen). Conversely, as Figure 4.42 indicates, the phosphorus feed levels are consistently lower than the reactor values (on average) (also indicated in Table 4.9). Thus, although no biological mechanism for total phosphorus removal exists, Figure 135 11 2 Days Missed Feed Time (Days) Figure 4.39 Daily Variation in Feed and Reactor TSS: AASD#2 8 - 7 - E, (0 5 o (0 3 (0 « « O > 5 - 4 - 2 Days Missed Feed + Fixed-Time o Real-Time - J — 20 T - r - 40 60 Time (Days) Figure 4.40 Daily Variation in Feed and Reactor VSS: AASD#2 136 750 2 Days Missed Feed 250 + Fixed-Time o Real-Time i 20 T 40 60 Time (Days) Figure 4.41 Fluctuations in Total Nitrogen Content: AASD#2 ^mm -J o> E ^m^ a. t 440 420 400 380 360 340 320 300 3 280 j2 260 H S- 240 O JC 220 a. "5! 200 CD o 18 160 140 120 100 • Feed + Fixed-Time o Real-Time 20 40 60 Time (Days) Figure 4.42 Fluctuations in Total Phosphorus Content: AASD#2 4.42 predicts that the mass balance calculation (Section 4.4.3) will yield a negative removal (i.e. an increase in phosphorus) similar in manner to the increase observed in AASD#1. Figures 4.43 and 4.44 show profiles of the change in pH and alkalinity with time. The pH profile appears to show a slight increase with time; however, the vagaries inherent in the pH measuring apparatus can account for this and it is unlikely that any meaningful trend exists. It is visually discernable however that the feed alkalinity is (on the average) larger than the reactor value. This is also verified in Table 4.9. It is predicted therefore that a mass balance for alkalinity (Section 4.4.3) will show a net removal, despite hopes that the consumption of alkalinity during nitrification would be offset by the production of alkalinity during denitrification. 4.4.3 Mass Balance Perspective As before, mass balances for solids (TSS and VSS), nitrogen (TKN + NOx), and phosphorus (TP) were performed around each reactor and these data have been compiled in Appendix F. Due to the KCN spike however, only 58 days of data (rather than the full 60) were used in the calculations. In addition, daily alkalinity measurements allowed a mass balance to be performed for this parameter as well. Tables 4.10 and 4.11 represent a collation of the results, while for comparative purposes, the results from AASD*1 are also presented. As shown (Table 4.10), the Fixed-Time reactor removed essentially the same levels (TSS, VSS, nitrogen and phosphorus) for AASD*2 as for AASD*1. This was unexpected, 138 7.4 -i 7.3 - 7.2 - 7.1 - 7 - &2 2 Days Missed Feed — Feed Fixed-Time o Real-Time 20 40 60 Time (Days) Figure 4.43 Daily Variation in Feed and Reactor pH: AASD*2 o u O CO a *5 < 260 250 240 230 220 210 200 190 180 170 160 150 140 130 120 110 • Feed +• Fixed-Time © Real-Time 2 Days Missed Feed 60 Time (Days) Figure 4.44 Daily Variation in Alkalinity: AASD*2 Table 4.10 Mass Balances for Fixed-Time Reactor: AASD#2 Mass Balance Parameter Percent Reduced TSS VSS Total N Total P Alkalinity Moving Average Balance AASD*1 10 Day SRT 14.7 % 16.8 % 17.5 % -6.5 % Moving Average Balance AASD*2 20 Day SRT 14.1 % 16.1 % 17.7 % -7.5 % 13.8 % Overall Mass Balance AASD*1 10 Day SRT 15.8 % 17.7 % 17.9 % -6.2 % Overall Mass Balance AASD*2 20 Day SRT 14.8 % 16.7 % 19.4 % -9.8 % 15.5 % Table 4.11 Mass Balances for Real-Time Reactor: AASD#2 Mass Balance Parameter Percent Reduced TSS VSS Total N . Total P Alkalinity Moving Average Balance AASD*1 10 Day SRT 15.2 % 18.0 % 19.5 % -6.9 % Moving Average Balance AASD*2 20 Day SRT 18.5 % 20.2 % 20.6 % -5.0 % Overall Mass Balance AASD*1 10 Day SRT 15.7 % 18.3 % 21.1 % -5.8 % 13.4 % J Overall Mass Balance AASD*2 20 Day SRT 19.9 % 21.5 % 25.9.% -5.3 % 16.2 % since AASD*2 operated at a 20 day SRT and the longer retention time was expected to produce significantly greater removals. No reason for this poor performance is readily apparent. The Real-Time reactor (Table 4.11) did show a marginal increase (2 to 4 percentage points, depending upon the mass balance method used) in TSS, VSS, and nitrogen; however, again this removal level is surprisingly low for the long SRT used. Jenkins and Mavinic (1989a) reported overall mass balance removal levels of 21.9 % for TSS, 23.9 % for VSS, 22.7 % for nitrogen and 7.35 % for phosphorus, for an aerobic-anoxic run at a 20 day SRT (20 °C) . As predicted from Figure 4.44, the alkalinity mass balance showed a net removal of alkalinity, even though the pH remained in the neutral range. It is suspected, therefore, that if the run had been extended, periodic adjustments would have become necessary to buffer the pH. Alternatively, the aerated to non-aerated fraction of the cycle could be altered (incorporating longer non-aerated periods) to produce more alkalinity to offset any pH drop that occurred. Due to the increase (relative to AASD*1) in the Real- Time reactor removals, small differences (up to 6 % depending upon the parameter and mass balance method used) exist in the performance of the two reactors. Again, it is not conclusive, but from a mass balance perspective, the Real-Time reactor may be removing (marginally) more than the Fixed-Time reactor (of the TSS, VSS and nitrogen). The lack of replication prevents a rigourous statement as to the statistical significance of these differences. 4.4.4 Evaluation: Unsteady Process Input Conditions During this run, the reactors were subjected to one spike each of sodium nitrate, ammonium chloride and hydrogen peroxide. All spikes were at a level equivalent to the "high" spikes detailed in AASD*1. The pertinent statistics are recorded in Tables 4.12, 4.13 and 4.14, while Figures 4.45 through 4.50 show vignettes of the reactor responses to each spike. The different failure categories are again highlighted on each figure. Both "Incomplete Denitrification" and "Incomplete Nitrification" failures were observed, as well as the "Missed- Knee" failure described earlier. Figures 4.45 and 4.46 reveal that the Real-Time reactor accommodated the sodium nitrate stress better than the Fixed-Time reactor, producing no failures directly attributable to the spike. Figures 4.47 and 4.48 indicate that both reactors had trouble assimilating the ammonium chloride spike, while Figures 4.49 and 4.50 indicate that the hydrogen peroxide spike created problems only for the Fixed-Time reactor. This latter failure is contrasted to run AASD*1 in which the hydrogen peroxide spikes produced no failures of any kind in either reactor. Tables 4.15 and 4.16 tabulate the number of failures for each reactor according to both the type of stress and category of failure. From the data, it is evident that the Fixed-Time reactor failed 11 times, while the Real-Time reactor failed 32 times. These values, however, must be normalized (for Table 4.12 Particulars of Sodium Nitrate Spike: AASD#2 Reactor Date Day Number Sampled Nitrate Air On (Hr:Min) Concentration Time of Spike Amount2 Sampling Time Concentration1 FT Oct/30/90 29 4:25 pm 2:00 1.64 mg/L 4:25 pm 129.6 mg 4:30 pm 6.16 mg/L RT Oct/30/90 29 4:00 pm 1:05 0.81 mg/L 4:00 pm 129.6 mg 4:05 pm 5.34 mg/L C o n c e n t r a t i o n i s measured a s N03-N mg/L zAmount i s based on a weight of Sodium N i t r a t e Table 4.13 Particulars of Ammonium Chloride Spike: AASD#2 Reactor Date Day Number Sampled Ammonia Air Off(Hr:Min) Concentration' Time of Spike Amount2 Sampling Time Concentration1 FT Nov/5/90 35 3:00 pm 0:45 0.61 mg/L 3:00 pm 129.6 mg 3:05 pm 6.79 mg/L RT Nov/5/90 35 2:40 pm 0:30 0.17 mg/L 2:40 pm 129.6 mg 2:45 pm 6.43 mg/L C o n c e n t r a t i o n i s measured a s NH3-N mg/L 2Amount i s based on a weight of Ammonium Ch lo r ide Table 4.14 Particulars of Hydrogen Peroxide Spike: AASD#2 Reactor Date Day Number Sampled D.O. Air On(Hr:Min) Concentration1 Time of Spike Amount2 Sampling Time Concentration1 FT Nov/20/90 50 9:45 am 2:30 2.75 mg/L 9:45 am 3 mL 9:47 am 10.9 mg/L RT Nov/20/90 50 12:15 pm 1:00 3.20 mg/L 12:15 pm 3 mL 12:17 pm 11.2 mg/L C o n c e n t r a t i o n i s measured a s Disso lved Oxygen (mg/L) 2Amount i s on a volume b a s i s of 3 % weight /volume H202 143 > E, Q- OC O 100 80 60 40 20 0 -20 -40 -60 -80 -100 -120 -140 -160 -180 -200 -220 Spiked @ 4:25 pm; NQj-N Concentration Increased From 1.64 mg/L to 6.16 mg/L 0RP1b A Failures - Incomplete Denitrification 20 40 Figure Time (Hrs) 4.45 Spike of Sodium Nitrate to FT Reactor: AASD#2 > a. cc O 100 80 60 40 20 0 -20 -40 -60 -80 -100 -120 -140 -160 -180 -200 -220 * Spiked @ 4:00 pm; NQj-N Concentration Increased from 0.81 mg/L to 5.34 mg/L ORP2a • Failure - Missed Knee 20 40 Figure Time (Hrs) 4.46 Spike of Sodium Nitrate to RT Reactor: AASD#2 144 > CC o 100 80 60 40 20 0 -20 -40 -60 -80 -100 -120 -140 -160 -180 -200 *Spiked @ 3:00 pm; Nhfe-N Cone. Increased from 0.61 ^ to 6.79 mg/L 0RP1c •Failures - Incomplete Nitrification 20 40 Time (Hrs) Figure 4.47 Spike of Ammonium Chloride to FT Reactor: AASD#2 > E, a. cc O -20 -40 -60 -80 - -100 - -120 - -140 -160 -180 H Failures Incomplete Nitrification Failure Missed Knee -200 * Spiked @ 2:40 pm; NHj-N Concentration Increased from 0.17 mg/L to 6.43 mg/L 0RP2b 0 20 40 Time (Hrs) Figure 4.48 Spike of Ammonium Chloride to RT Reactor: AASD#2 145 > Q. EC o 140 120 100 80 60 40 20 0 •20 -40 -60 •80 -100 -120 -140 -160 -180 * Spiked @ 9:45 am; Dissolved Oxygen Concentration Increased from 2.75 mg/L to 10.9 mg/L ORP1c A Failure - Incomplete Denitiification 12 16 Time (Hrs) Figure 4.49 Spike of Hydrogen Peroxide to FT Reactor: AASD#2 > CL tr o 180 170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0 ORP2a Spiked @ 12:15 pm; D.O. Increased from 3.20 to 11.2 mg/L T 12 —f— 16 l 20 24 Time (Hrs) Figure 4.50 Spike of Hydrogen Peroxide to RT Reactor: AASD#2 Table 4.15 Failures Associated with FT Reactor Operation: AASD#2 Type of Stress Normal Operation Sodium Nitrate Spike Ammonia Chloride Spike Hydrogen Peroxide Spike Ommission of Daily Feed Total Number of Failures Incomplete Denitrification Failure 1 3 0 1 1 6 Incomplete Nitrification Failure 1 0 4 0 0 5 Missed Nitrate Breakpoint Failure 0 0 0 0 0 0 Total Number 2 3 4 1 1 11 Table 4.16 Failures Associated with RT Reactor Operation: AASD#2 Type of Stress Normal Operation Sodium Nitrate Spike Ammonia Chloride Spike Hydrogen Peroxide Spike Ommission of Daily Feed Total Number of Failures Incomplete Denitrification Failure 0 0 0 0 2 2 Incomplete Nitrification Failure 1 0 4 0 0 5 Missed Nitrate Breakpoint Failure 25 0 0 0 0 25 Total Number 26 0 4 0 2 32 each reactor) against the total number of cycles during the run. For example, the Real-Time reactor with its short cycle length had many more opportunities than the Fixed-Time reactor to fail. Accordingly, the Fixed-Time reactor sustained 217 cycles (a failure rate of 5.1 %) , while the Real-Time reactor underwent 525 cycles (a failure rate of 6.1 %) . Thus, from a "failures" perspective, both reactors performed essentially the same. Since the majority of the Real-Time failures were software-based, more sophisticated programming techniques may be able to reduce or even eliminate the "Missed-Knee" category of failure. If this occurs, there may be grounds for stating that the Real-Time AASD#2 operating strategy holds more promise of being better able to control the system; especially since it may have performed better than the Fixed-Time reactor in the mass balance category. Finally, Figures 4.51 and 4.52 show the response of each reactor to the spike of 56 mg/L (0.5 millimoles/litre of potassium cyanide). This concentration is one half that suggested by the microbiological department at UBC, however it is clear that the KCN immediately affected the micro-organisms. Cyanide prevents the reaction of oxygen in the overall energy- producing process by binding with ferricytochrome oxidase, the last cytochrome in the oxidative phosphorylation pathway. In both reactors, the ORP gradually rose again as the concentration of dissolved oxygen increased in the reactor (to over 7 mg/L), due to the lack of bacterial demand for an electron acceptor. 148 > E. Q. CC o Spiked with KCN 56 mg/L @ 2:30 pm Time (Hrs) Figure 4.51 Spike of Potassium Cyanide to FT Reactor: AASD#2 200 150 - 100 - 50 ">* £ 0 Q. CC o -50 - -100 - -150 - -200 * Spiked with KCN 56 mg/L @ 2:20 pm Time (Hrs) Figure 4.52 Spike of Potassium Cyanide to RT Reactor: AASD#2 CHAPTER 5 BIOLOGICAL PHOSPHORUS REMOVAL (BIO-P) EXPERIMENTS 5.l Operating Characteristics and ORP Profiles The biological phosphorus removal experiment was partitioned into two runs (Bio-P*l and Bio-P*2) , with each run being 2 SRTs (40 days) in length. The rationale for this segmentation was somewhat artificial, in that a solenoid malfunction drained one-half of the Real-Time reactor contents down the sink at the 40 day mark. It was felt however that the period was of sufficient length to extract useful data, and thus the second run was halted after a similar period of time. During Bio-P#l, the raw feed was supplemented with inorganic phosphorus (Na2HP04) to approximately a concentration of 7 mg/L ortho-P (calculated in Appendix G) . However, the reactors failed to remove phosphorus during this run; therefore, this practice was discontinued when the reactors were restarted. Thus, during Bio-P#2, the feed to the reactors contained whatever ortho-P concentration naturally occurred in the pilot plant influent (usually around 2 mg/L). During both runs, the pilot plant strategy of adding alkalinity (NaHC03) to the raw sewage was continued in order to maintain the pH in the neutral range. The reactors were operated at a 20 day SRT, since that reduced the need for acclimation time between the pilot plant and the reactor conditions. In theory, with a 20 day SRT, 240 mL of liquid should have been wasted on a daily basis. The solids level, however, declined dramatically over the run (Section 5.2) and therefore wasting was occasionally halted. The Fixed-Time reactor operated with a scheduled time ( 1 hr 25 min into the anoxic period) , for the addition of 3 0 mg acetate/litre of influent (calculated in Appendix G). In contrast, the Real-Time reactor's acetate addition was triggered by the detection of the nitrate breakpoint. Before discussing the performance of the reactors, it is useful to consider the "ideal" ORP curve shape, generated under SBR Bio-P conditions. Unlike the AASD experiments (which had a distinct "indigenous" curve, particular to each reactor's operation), the curve shown in Figure 5.1 was not ubiquitous enough to be considered as "characteristic" of normal Bio-P operation. The reasons for this will be explained later. Clearly evident in Figure 5.1 are the three distinct zones of the Bio-P process, with a sharp, pronounced nitrate knee initiating the Real-Time addition of acetate. Figure 5.1 does not, by itself, imply perfect biological conditions for the removal of phosphorus; for even when this curve shape was obtained, the reactors seldom achieved consistent excess removal of phosphorus. As will be discussed at the end of Section 5.2, there is a host of biological and chemical parameters that must be in harmony in order to ensure good P removal. For comparison, Figure 5.2 illustrates a frequent shape of the ORP curve, generated when the reactor denitrified immediately after the FILL period had finished. The curve's extremely rapid decline meant that the Real-Time reactor's software could not trap the knee in any of the 3 cycles that day. The major reason for this seems to be that the Bio-P 151 Time (Hrs) Figure 5.1 "Ideal" ORP Profile Under Bio-P Conditions -20 - -40 - -60 - -80 - -100 -120 - -140 - -160 - -180 - -200 - -220 - -240 Software Cannot Trap Nitrate Knees Because They Occur Too Quickly if At All Cycle 3 Bio-P #2 Rapid Denitrification immediately After Fill 3 Cycles Per Day -r 3 Time (Hrs) Figure 5.2 Software Failure Due to Rapid Denitrification process is considered to be a highly-loaded carbon system, as compared to the AASD system which has very little soluble carbon available. Although not always the case in this experiment, in theory, a Bio-P system should have plenty of carbon available for denitrification, especially if relatively fresh feed has just been placed in the feed bucket. Since nitrate reduction is the first sequence in a Bio-P SBR, the denitrifying bacteria have few organisms competing with them for access to the substrate. Thus, they are easily (and apparently rapidly) able to eliminate the nitrates, causing the breakpoint to occur in the first several minutes. A number of attempts were made during both runs to track the phosphorus and nitrate behaviour over the course of one complete cycle. Figures 5.3 and 5.4 show the best curves obtained during Bio-P*l. In the Fixed-Time reactor (Figure 5.3), the nitrate breakpoint occurs just prior to the addition of acetate, the impact of which, triggers the classical release/uptake phenomena necessary for Bio-P removal. As can be seen however, the reactor failed to take up excess phosphorus and thus the effluent was discharged from the reactor at essentially the same level at which it entered. Although acetate was measured during this track, it was utilised so quickly that none was detected on the gas chromatograph. Figure 5.4 shows the behaviour of the Real-Time reactor. As has been illustrated earlier and as typified by this example, the nitrate disappeared almost immediately, causing true anaerobic conditions to develop. This was accompanied by a slow 153 20 15 10 - 5 - REACT(Unaerated) ; REACT(Aerated) Nitrate Knee Occurs Just Prior To Addition of Acetate -5 - -10 - -15 - -20 Fixed-Time 1 hr. 25 min. BiO-P #1 Fixed-Time Reactor Profile ORP1c - March/26/91 ORP1e ORP1c + Ortho-P o NOx - r - 13 9 11  15 Time (Hrs) Figure 5.3 Fixed-Time Reactor Track Study: Bio-P#1 25 20 - 15 - 10 - 5 - -5 H -10 -15 -20 -25 Computer Initiated Acetate Addition Just Prior to React (Aerated) — NOx ; 9 » • ? « - REACT (Unaerated) REACT (Aerated) No Observable Nitrate Knee Since NOx is Already Zero Bio-P #1 Real-Time Reactor Profile ORP2b - March 26/91 \ ORP2b ORP2b + Ortho-P o NOx — I — 1-t — I — 13 15 Time (Hrs) Figure 5.4 Real-Time Reactor Track Study: Bio-P#1 release of phosphorus, further accentuated by the addition of acetate, 2 hours and 40 minutes into the cycle (just prior to aeration). The computer added the acetate as a "fail-safe" measure, since at that time it "assumed" that the breakpoint had been missed. Again, whatever phosphorus was released was subsequently taken back up during aeration; however, no "excess" removal was observed. Another frequent observation was the addition of acetate actually causing the knee itself, as shown in Figures 5.5 and 5.6. The Fixed-Time reactor (Figure 5.5) depicts the knee occurring at precisely the same time (i.e. 1 hour 25 minutes) into all 3 cycles. Although not directly confirmed by NOx analysis, this implies that acetate is being used as a source of easily oxidizable carbon for denitrification purposes, rather than for carbon storage by Bio-P organisms. Similarly, the Real- Time reactor (Figure 5.6) shows the computer initiating the acetate addition (since the knee had not been detected) after 2 hours and 40 minutes. This carbon is sufficient to complete the denitrification reaction which causes the nitrate breakpoint just prior to the onset of aeration. The best track studies available for Bio-P#2 also reflect this trend. Figure 5.7 shows the addition of acetate to the Fixed-Time reactor causing a sharp drop in the nitrate concentration, with the breakpoint occurring shortly thereafter. In this particular example, the phosphorus was removed to a very low level; therefore, it appeared that the acetate was being partitioned between being used for nitrate reduction by 155 60 40 - 20 - 0 -20 H -40 -60 - -80 - -100 - -120 -140 -160 - -180 - -200 -220 No Observable 0.0. Breakpoints However 0.0. Is Likely Large VTA Addition Causes Nitrate Knee To Occur 1 hr. 25 min. Into AH 3 Cycles BlC-P#2 Fixed-Time Reactor Profile 91-05-17.FT 0RP1b Tlme(Hrs) Figure 5.5 VFA-Caused Breakpoints in Fixed-Time Reactor 120 100 H 80 60 H 40 20 H 0 -20 -40 - -60 - -80 - -100 - -120 REACT (Aerated) Bio-P #2 Real-Time Reactor Profile 91-05-1 aRT ORP2c 1 3 7 Time (Hrs) Figure 5.6 VFA-Caused Breakpoints in Real-Time Reactor 156 REACT (Unaerated) REACT (Aerated) BioP #2 Fixed-Time Reactor Praflle 0RP1b May/7/91 — 0RP1b + Ortho-P o NOx 15 Figure Time (Hrs) 5.7 Fixed-Time Reactor Track Study: Bio-P#2 denitrifiers and being used for carbon storage by Bio-P organisms. The Real-Time reactor's breakpoint (Figure 5.8) was again induced by the addition of acetate, at the last possible minute before aeration. This was followed by a quick release prior to aerated uptake of phosphorus. One recurring phenomena was the way in which the shape of the ORP curve was influenced by the operation of the experimental system. In particular, a delay in the time of occurrence for the nitrate breakpoint was often observed as the feed sludge weakened with time. As has been mentioned, raw sewage was collected in carboys and stored in the cold room for up to 12 days. Since the feed bucket could hold up to 3 days worth of sewage, every 4th day the bucket was replenished with "fresh/stored" sewage from the cold room. However, not only was there a decline in the carbon content in the raw sewage stored in the cold room (Figure 5.9), but there was also a significant decline in the carbon content during the 3 days in between "fresh/stored" feed (Figure 5.10) (the data used to plot these graphs have been included in Appendix H). This latter decline occurred because the feed bucket sewage was continuously mixed (albeit at a very slow rate) in order to keep the solids in suspension. Despite being covered to minimize air entrainment, it is evident that sufficient air must have entered the mixture to allow bacteria to utilize short-chain organic compounds generated from the conversion of complex organics in the raw sewage. The decrease in carbon content was therefore reflected in 158 REACT (Unaerated) BiO-P # 2 Real-Time Reactor Profile 0RP2b May/7/91 ORP2b + Ortho-P 0RP2b 11 13 I 15 Time (Hrs) Figure 5.8 Real-Time Reactor Track Study: Bio-P#2 o» E, O g o 6" i- Q O O o a a Decline in Carbon Content Raw Sewage Stored in Cold Room Soluble COD 7 9 Time (Days) Figure 5.9 Decline in Carbon Content: Stored in Cold Room 110 100 - 90 a E IT- 80 -U O I- o t- iS \- Q O U C 70 60 50 - C o i_ a U Decline in Carbon Content Raw Sewage Stored in Feed Bucket Soluble COD Organic Carbon 1.8 £ 2 Time (Days) 3.4 3.8 Figure 5.10 Decline in Carbon Content: Stored in Feed Bucket a delay in the time that the knee occurred in any given cycle. This is illustrated in Figures 5.11 and 5.12. Figure 5.11 tracks the knee over the three cycles of the day and as pictured, there is no "average time" for denitrification, since it is constantly lengthening as a function of the strength of the incoming feed. Figure 5.12 continues Figure 5.11 into the next day, and illustrates how, during the last cycle before replenishment with fresh feed (from the cold room), the reactor "failed" to completely denitrify, in a manner reminiscent of the AASD set of experiments. The 6th cycle occurred after replenishment and consequently the time taken to completely denitrify was considerably shortened once again. The fact that the knee associated with cycle 6 occurs slightly later than the knee associated with the first cycle, may be indicative of the gradual decline in the carbon content of the feed stored in the cold room itself. 5.2 Chemical Characteristics of Bio-P Experiments Tables 5.1 and 5.2 detail some selected statistics of the solids, nitrogen and phosphorus levels measured during both Bio- P#l and Bio-P*2. The detailed chemical data have been presented in Appendix H. In both experiments, the feed TSS level was approximately 100 mg/L (Figures 5.13 and 5.14). Bio-P*2 however experienced a much larger standard deviation as indicated in Table 5.2. Figure 5.14 illustrates the major cause of this, as occurring between the 3rd and 4th data points on the graph. The first 3 points are from sewage stored in the cold room, but initially collected 161 60 40 H 20 0 -20 H -40 -60 -80 -100 - -120 -140 -160 -180 -200 1 Delay in Time of Nitrate Knee Occurrence, Likely a Function of the Carbon Decay in the Feed Storage Bucket Cycle #3 Cycle #2 Cycle #1 Bio-P #1 Real-Time Reactor Profile ORP2b March 6/91 Time (Hrs) Figure 5.11 Delay in Time of Nitrate Breakpoint Occurrence -200 Bio-P #1 Real-Time Reactor Profile March 6-7/91 Denitrification Probably Caused by VFA Addition Just Before REACT (Aerated) Fresh Feed from Cold Room Shortens Denitrification Time Again 1 Time (Hrs) Figure 5.12 Two Day Track of Delayed Nitrate Breakpoint Table 5.1 Solids, Nitrogen and Phosphorus Chemical Data: Bio-P#1 Chemical Parameter TSS (mg/L) VSS (mg/L) TKN - Feed (mg/L) % N - RCTR (%) NOx-N (mg/L) NHj-N (mg/L) TP - Feed (mg/L) %P - RCTR (%P) Ortho-P (mg/L) Statistic Maximum Mean Minimum Std.Dev. Maximum Mean Minimum Std.Dev. Maximum Mean Minimum Std.Dev. Maximum Mean Minimum Std.Dev. Maximum Mean Minimum Std.Dev. Maximum Mean Minimum Std.Dev. Maximum Mean Minimum Std.Dev. Maximum Mean Minimum Std.Dev. FEED 121 100 77 15 107 88 68 13 30.3 28.4 26.8 1.4 0.35 0.14 0.00 0.09 17.0 13.0 9.8 2.4 9.7 9.5 9.1 0.4 7.64 6.44 4.91 0.87 | Fixed-Time RCTR Effl 2376 11 2124 4 1620 1 226 3 1834 11 1616 4 1280 1 196 3 5.72 5.32 4.81 0.25 9.43 7.97 6.31 0.94 0.1 N/D N/D N/D 3.56 3.25 2.92 0.25 10.70 6.38 3.26 2.17 Real-Time RCTR Effl 2612 5 2281 3 1890 1 205 1 2012 5 1727 3 1392 1 195 1 5.19 4.90 4.53 0.10 12.89 7.70 2.69 2.40 2.5 0.4 N/D 0.8 4.07 3.20 2.53 0.40 8.80 5.60 2.51 1.70 J 163 Table 5.2 Solids, Nitrogen and Phosphorus Chemical Data: Bio-P#2 Chemical Parameter TSS (mg/L) vss (mg/L) TKN - Feed (mg/L) % N - RCTR (%) NOx-N (mg/L) NH3-N (mg/L) TP - Feed (mg/L) %P - RCTR (%P) Ortho-P (mg/L) Statistic Maximum Mean Minimum Std.Dev. Maximum Mean Minimum Std.Dev. Maximum Mean Minimum Std.Dev. Maximum Mean Minimum Std.Dev. Maximum Mean Minimum Std.Dev. Maximum Mean Minimum Std.Dev. Maximum Mean Minimum Std.Dev. Maximum Mean Minimum Std.Dev. FEED 181 107 65 41 162 97 59 36 41.2 31.0 24.0 7.4 0.30 0.16 0.04 0.06 13.8 12.4 11.6 0.6 6.3 4.7 3.7 1.1 3.18 2.19 1.60 0.36 Fixed-Time RCTR Effl 3018 10 2194 6 1598 2 417 2 2648 10 1825 6 1266 2 410 2 6.82 6.32 5.45 0.36 9.71 8.49 7.19 0.65 N/D N/D N/D N/D 3.36 2.50 1.12 0.71 2.07 0.52 0.00 0.78 Real-Time RCTR Effl 3026 10 2159 6 1630 2 439 3 2650 10 1791 6 1276 2 431 3 6.26 5.83 5.53 0.24 10.68 9.00 7.40 0.88 N/D N/D N/D N/D 3.52 2.54 1.22 0.71 1.92 0.52 0.01 0.59 130 120 - 110 - 100 - 90 - 80 - 70 - 60 - 50 - 40 - 30 - 20 - 10 - FMdTSS FT Effluent TSS <N— Bio-P #1 • FaedTSS * FTEffluentTSS o RT Effluent TSS RT Effluent TSS 30 40 Time (Days) Figure 5.13 Variation in Feed and Effluent TSS: Bio-P#1 190 Feed TSS Bio-P #2 • Feed TSS + FTEffluentTSS o RT Effluent TSS 40 Time (Days) Figure 5.14 Variation in Feed and Effluent TSS: Bio-P#2 during a relatively dry weather spell. In contrast, subsequent data points are from feed collections made when the sewage had been diluted by the influx of water from several days of rain. This caused a significant drop in the feed TSS as depicted in Figure 5.14. In both figures the reactor effluents for each run were generally less than 10 mg/L. Visual inspection of the sludge settling characteristics revealed a highly clarified effluent, produced by a sludge blanket interface settling well below the decanting solenoid port. The solids variation inside the reactors is shown in Figures 5.15 and 5.16. In the latter experiment especially, the TSS level declined dramatically, with bacterial growth not being sufficient to counterbalance the loss in solids due to wastage. Wasting was halted several times (as reflected in occasional horizontal plateaus in the latter portion of the Bio-P#2 curve); however, it is evident that this was not practiced frequently enough to stem the decline in solids. This will be expanded upon in more detail later, when discussing the F:M ratio. Ultimately though this means that the actual SRT is substantially less than 20 days; a factor having major ramifications for the P removal performance. The VSS/TSS ratio was greater in the Feed (Bio-P#l - 0.88, Bio-P*2 - 0.90) than the Fixed-Time (Bio-P#l - 0.76, Bio-P*2 - 0.83) and Real-Time (Bio-P#l - 0.76, Bio-P*2 - 0.82) reactors, respectively. In both runs, the few effluent solids that were released as decanted supernatant (generally less than 10 mg/L 166 11 2.7 2.6 2.5 2.4 2 J 2 J 2.1 2.0 1.9 1.3 1.7 1.6 Real-Time RCTR Bio-P #1 Fixed-Time TSS Real-Time TSS - r - 10 — I 40 Time (Days) Figure 5.15 Variation in Reactor TSS: Bio-P#1 3.1 II 3.0 - 2.9 - 2 * - 2.7 - 2.6 - 2J5 - 2.4 - 2J - Z2 - 2.1 - 2.0 - 1.9 - 1 3 - 1.7 - 1.6 - 1J 4- Fixed-Tlme RCTR • + Bio-P #2 Fixed-Time TSS Real-Time TSS Real-Time RCTR i 10 20 I 30 - 1 40 Time (Days) Figure 5.16 Variation in Reactor TSS: Bio-P#2 (Appendix H)) were essentially all volatile solids. The feed sewage TKN was approximately 30 mg/L, with about 40 percent being in the form of ammonia. In almost all cases the ammonia was completely nitrified, with effluent NH3 values below the detectable limit of 0.05 mg/L. Nitrate levels in the effluent were between 7 and 9 mg/L; these could not be denitrified, since a single SBR operating under this strategy cannot be optimized to obtain concurrent nitrogen and phosphorus removal. Manning and Irvine (1985), operating a similar system, also reported a highly nitrified effluent (> 27 mg/L NOx). Due to inorganic P additions to the feed during Bio-P*l, well over 68 % of the TP (average value of 9.5 mg/L) was in the form of soluble ortho-P. Bio-P*2 however had 47 % of the TP (average value 4.7 mg/L) in soluble form. Figures 5.17 and 5.18 track the progress of the % N and % P values for both reactors (both runs) and indicate that the second run had a slightly larger average % N value than the first run. This is verified in Tables 5.1 and 5.2. In both runs (especially Bio-P#2) , there was a tendency for the % P to increase with time. In theory, this should occur as phosphorus is removed from the bulk liquid; however, the fact that little ortho-P removal was observed makes this observed trend more fortuitous than certain. In fact, the ortho-P behaviour was less than ideal as illustrated in Figures 5.19 and 5.20. In Figure 5.19, the reactor's effluent phosphorus level oscillates around the influent feed phosphorus level; thus, on the average, whatever 5.8 5.6 5.4 5.2 5.0 4.8 4.6 4.4 4J2 4.0 3.3 3.6 3.4 1 2 3.0 2.3 2.6 2.4 %N FT RCTR %NRTHCTR Bio-P #1 + % N FT RCTR A % H RT RCTR • % P FT RCTR o % P RT RCTR %P FT RCTR 10 20 30 40 Time (Days) Figure 5.17 Reactor Plot of Percent N and P: Bio-P#1 6 - 2 - % N FT RCTR Bio-P#2 + % N FT RCTR A % N RT RCTR • % P FT RCTR o % P RT RCTR % P FT RCTR l 10 20 Time (Days) i 30 40 Figure 5.18 Reactor Plot of Percent N and P: Bio-P#2 169 11 10 - 9 - 8 - 7 - 6 - 4 H 3 - Fixed-Time RCTR BIo-P #1 • Feed Ortho-P + Fixed-Time Ortho-P o Real-Time Ortho-P 10 20 30 40 Time (Days) Figure 5.19 Track of Ortho-P Concentrations: Bio-P#1 12 3.0 - 2.8 - 2.6 - 2.4 - 2.2 - 2.0 - 1.8 - 1.6 - 1.4 - 1.2 - 1.0 - 0.8 - 0.6 - 0.4 - 0.2 0 Bio-P #2 • Feed Ortho-P + Fixed-Time Ortho-P o Real-Time Ortho-P Real-Time RCTR Fixed-Time RCTR i 10 Time (Days) Figure 5.20 Track of Ortho-P Concentrations: Bio-P#2 entered the reactor was also released from the reactor. The parallel behaviour of both reactors (in terms of synchronous high/low oscillations) can be correlated with the decline in the carbon content in the feed bucket as elaborated below. Ortho-P was measured every second day; thus, one sample would be taken relatively close to the day in which fresh sewage had been added to replenish the feed bucket. On such days the feed would be relatively rich in carbon, and therefore denitrification would proceed rapidly (Figure 5.2) and be followed by a good release of phosphorus when the acetate was added to the reactor. Subsequently, during the aerated sequence, the microorganisms would take up phosphorus and the effluent level would be below average, with some "excess" removal observed. The next samples, however, would be taken just prior to replenishing the feed bucket; thus, they would be furthest from the previous "fresh/stored" feed day. Denitrification would therefore be delayed (perhaps even incomplete) and some (or all) of the acetate added would be used for denitrification purposes, rather than for carbon storage by Bio-P organisms. On such days, relatively large values of effluent P were observed, because aerated P uptake had been preceded by poor P release. This established the alternating high/low effluent ortho-P pattern shown in Figure 5.19. The decline in the carbon content in the feed bucket and the lack of steady-state conditions are advocated as the major causes of the poor P removal observed during this research. This will be emphasized repeatedly in later sections of the analysis. During Bio-P#2 (Figure 5.20), the raw sewage influent P values were much lower than Bio-P#l, due to the absence of inorganic P supplements. Good P removal was observed only up to where the feed sewage had been subjected to several days of rain. The dilution of the carbon in the sewage (coupled with its subsequent decay), although producing an attendant drop in the influent P value, was evidently enough to push the P values into exhibiting the parallel high/low behaviour, as explained above. Table 5.3 and 5.4 detail the carbon, oxygen, alkalinity and pH statistics for both runs. Figures 5.21 and 5.22 depict the soluble COD behaviour of the feed and reactors during each run. The effluent from both reactors was generally below 30 mg/L for Bio-P#l and 20 mg/L for Bio-P*2. Using the mean values, this made for soluble COD removals of 81 % and 83 % for the FT and RT reactors (Bio-P#l) and 75 % and 79 % for the FT and RT reactors (Bio-P#2) . As indicated however, significant removal was occurring inside the feed bucket, during the days in between replenishment. Figure 5.22 (Bio-P*2) reveals the sharp drop in feed COD from the dry spell to the wet period, commencing after the 3rd data point. Pilot plant data showed a drop in the influent total COD from over 400 mg/L to 230 mg/L, for these collection dates. Figures 5.23 and 5.24 show carbon plots for the feed from both runs. During Bio-P*l (Figure 5.23), both the inorganic and organic carbon comprise roughly equal amounts of the total carbon. This is substantiated in Table 5.3. During run Bio-P#2 Table 5.3 Carbon, Oxygen, Alkalinity and pH Data: Bio-P#1 Chemical Parameter Carbon (mg/L) COD (mg/L) Dissolved Oxygen (mg.L) Alkalinity pH Statistic Maximum Mean Minimum Std.Dev. Maximum Mean Minimum Std.Dev. Maximum Mean Minimum Std.Dev. Maximum Mean Minimum Std.Dev. Maximum Mean Minimum Std.Dev. FEED TC IC TOC 114 66 60 95 48 47 79 31 38 11 10 6 155 143 118 13 320 237 164 47 7.56 7.28 6.81 0.21 Fixed-Time TC IC TOC 63 52 11 45 37 8 31 25 6 11 10 1 29 27 20 3 7.00 4.60 0.70 2.07 310 254 192 37 7.37 7.12 6.64 0.18 Real-Time TC IC TOC 63 53 10 45 38 7 31 25 6 10 9 1 28 25 15 4 6.90 2.90 0.70 2.37 312 253 178 36 7.38 7.15 6.97 0.14 J Table 5.4 Carbon, Oxygen, Alkalinity and phi Data: Bio-P#2 Chemical Parameter Carbon (mg/L) COD (mg/L) Dissolved Oxygen (mg.L) Alkalinity pH Statistic Maximum Mean Minimum Std.Dev. Maximum Mean Minimum Std.Dev. Maximum Mean Minimum Std.Dev. Maximum Mean Minimum Std.Dev. Maximum Mean Minimum Std.Dev. FEED TC IC TOC 129 79 50 93 56 37 74 42 28 15 11 8 72 53 42 11 360 265 210 46 7.59 7.38 7.09 0.16 Fixed-Time TC IC TOC 78 64 14 55 47 8 38 31 6 13 12 2 20 13 10 3 8.00 6.65 1.20 1.36 392 277 172 66 7.86 7.54 7.11 0.19 Real-Time TC IC TOC 78 66 13 56 47 8 35 28 6 14 13 2 18 11 4 3 8.00 7.26 4.20 0.84 390 282 170 69 7.97 7.66 7.34 0.19 173 160 150 - 140 - 130 120 - 110 - 100 - 90 - 80 70 - 60 - 50 - 40 - 30 20 H 10 Fixed-Time COO Feed COO Bio-P #1 Feed COO + Fixed-Time COD o Real-Time COO Real-Time COD T 10 30 40 20 Time (Days) Figure 5.21 Variation in Feed and Reactor COD: Bio-P#1 80 70 - 60 50 - 40 30 20 - 10 - Fixed-Time COD Feed COD 10 Bio-P#2 Feed COD + Fixed-Time COD o Real-Time COD 20 30 40 Time (Days) Figure 5.22 Variation in Feed and Reactor COD: Bio-P#2 174 120 110 - 100 - 90 - 80 - 70 - 60 50 - 40 - 30 - 20 - 10 Feed TOC BiO-P # 1 • FeedTC + Feed IC o Feed TOC 10 20 30 40 Time (Days) Figure 5.23 Carbon (TC, IC, TOC) Plots for Feed: Bio-P#1 130 Bio-P#2 • FeedTC Feed TOC - J — 10 20 Time (Days) T - 30 40 Figure 5.24 Carbon (TC, IC, TOC) Plots for Feed: Bio-P#2 however, the percentage of inorganic carbon is larger than the organic carbon, another indication of the generally "weaker" sewage used during this run. The decline in feed TOC from the 3rd to 4th data points (Bio-P#2) is not as marked as it was in the COD profile; however, it is still sufficiently pronounced, to be suggested as a partial reason for the sudden change in the P behaviour from generally stable low values to the fluctuating behaviour described earlier. Figures 5.25 and 5.2 6 illustrate (for both runs) the behaviour of the carbon in the Fixed-Time reactor. As can be seen, the TOC was very low (< 10 mg/L) and fairly constant as indicated by the horizontal nature of the TOC plot and the relatively even distance separating the IC from the TC profile. The Real-Time reactor, if plotted, would show a similar trend. The large standard deviations (Tables 5.3 and 5.4) for the reactor dissolved oxygen concentrations, are indicative of the lack of control achievable at the lab scale. Small adjustments to the needle flow control valves produced wide swings in the D.O measurement in the bulk liquid. A plot of these values would be essentially stochastic and of little value, especially since, in the Real-Time reactor (Bio-P*l) , the standard deviation was almost as large as the mean. In run Bio-P#2 no attempt was made to control the oxygen supply and thus the D.O. level was often at a maximum, usually around 7 mg/L. The alkalinity values were also random in nature, reflecting the casual manner in which two scoops of sodium bicarbonate were tossed into the feed bucket, every time it was 176 120 110 - 100 - 90 - 80 70 - 60 - 50 - 40 - 30 - 20 10 H 0 Bio-P #1 a Fixed-Time TC x Fixed-Time IC 7 Fixed-Time TOC Fixed-Time TC i 10 20 30 40 Time (Days) 5.25 Carbon (TC, IC, TOC) Plots for FT RCTR: Bio-P#1 Bio-P #2 A Fixed-Time TC x Fixed-Time IC v Fixed-Time TOC 40 Figure 5.26 Carbon (TC, IC, TOC) Plots for FT RCTR: Bio-P#2 filled. Plots of the variation in pH with time are shown in Figures 5.27 and 5.28; since all pH measurements fall within the neutral range, it is clear that the alkalinity additions were more than sufficient to supply the consumptive needs of nitrification. Some unduly large pH values were recorded, and it is suspected that some C02 was being stripped from solution due to excessive aeration. When all of the preceding observations are considered, it is evident that several key biological and chemical parameters must be in balance in order to consistently achieve good P removal. One such relationship is the TKN/COD ratio, which in effect quantifies the denitrification capacity of the influent sewage. Researchers have long recognized the importance of this ratio. For example, Ekama et al., (1984) critiqued the Modified Bardenpho (Phoredox) process and predicted it would experience complete nitrification/denitrification, only when the influent sewage possessed a TKN/COD ratio less than 0.07. (i.e. a COD/TKN ratio of greater than 14:1). TKN/COD ratios larger than 0.07 seemed to have difficulty in providing enough carbon for denitrification. The need to accommodate lower strength sewages was one reason (among others) behind the development of the UCT process, reported to be able to cope with TKN/COD ratios of up to 0.14 (i.e. COD/TKN ratios as low as 7:1). Working within these ratios, Ekama et al., (1984) were able to guarantee enough carbon available (in most instances) to ensure that nitrates did not bleed through to the anaerobic reactor. 6.8 -\ | 1 1 ; 1 1 a 1 j 0 10 20 30 40 Time (Days) Figure 5.27 Variation in pH Feed, FT and RT RCTRS: Bio-P#1 0 10 20 30 40 Time (Days) Figure 5.28 Variation in pH Feed, FT and RT RCTRS: Bio-P#2 Barnard et al. (1985), however, showed that the Kelowna B.C., Bio-P process was able to achieve good P removal with ratios between 7:1 and 10:1, despite predictions that it would need a COD/TKN ratio of at least 14:1 in order to function effectively, The pilot plant's TKN/COD ratio is usually between 0.06 and 0.08 (Comeau (1989)). Unfortunately, in this research, total COD values are only available for the feed collection days. Accordingly, the average total CODs for Bio-P*l and Bio-P#2 were 261 mg/L and 292 mg/L, respectively. Using the mean values for TKN (Tables 5.1 and 5.2), a TKN/COD ratio of 0.11 was calculated for both Bio-P*l and Bio- P*2. As large as this ratio is, it is still lower than the actual ratio present on most days, since the COD values do not consider the decline in COD during the days in between replenishment of the feed bucket. Moreover, in this experiment, the ratio was unusually affected by the vagaries in local weather patterns, since one collection would influence the following 12 days. The fact that the TKN/COD ratio on most days is quite large is somewhat overshadowed by the peculiarity of the SBR treatment method, in that it transposes the traditional (ex. UCT or UBC) order of zones, from anaerobic, anoxic, aerobic, to anoxic, anaerobic, aerobic. This has the effect of accentuating the concern about whether sufficient carbon is available for Bio-P organisms to predominate. To illustrate, in the traditional sequence, the emphasis has not only been to ensure enough carbon enters the first (anaerobic) zone, but also that it enters in the right form (i.e. as rapidly biodegradable (RBD) carbon (Nicholls and Osborn (1979)). The RBD fraction of the carbon is understood to be that portion of the carbon that can easily pass through the cytoplasmic membrane of the cell by diffusion or osmotic pressure. RBD carbon is usually comprised of short-chain fatty acids (SCFA), such as acetate, propionate, butyrate etc., and much work has been done at UBC on processes designed to enhance the production of these substrates in the incoming sewage (Rabinowitz et al. (1986), (1987), Elefsiniotis (1992)). Seibritz, Ekama and Marais (1983) have established that there must be at least 25 mg/L of RBD COD available in the anaerobic zone to ensure good P release/carbon storage. Further to this, there must be enough remaining carbon to reduce the nitrates in the second (anoxic) zone, as implied by the earlier comments about the TKN/COD ratio. If insufficient carbon is available, nitrates will bleed through (via the recycle line) into the anaerobic zone, inhibiting P release. Current theories suggest that nitrates inhibit P release (as measured by bulk liquid orthophosphate concentrations) by providing an electron acceptor for facultative denitrifiers. Consequently, Bio-P organisms do not have exclusive access to all of the RBD substrate. There is, however, considerable evidence (Hascoet and Florentz (1985), Vlekke (1988) and Comeau (1989)), that at least a fraction of Bio-P bacteria are capable of assimilating polyphosphates in the presence of nitrates. Thus, the reason for poor P release (when nitrates are present in the anaerobic zone), becomes one of competition between Bio-P organisms (rather than inhibition by other organisms) and is a function of the relative mix of organisms in the wastewater (those releasing P and those accumulating P). Although it is likely that a combination of the above reasons is responsible for P release not being as vigourous in the presence of nitrates, this research will explain its results from the first premise (i.e. nitrates provide electron acceptors for bacteria, which in the process of denitrifying, utilize some of the carbon which should have been stored by Bio-P bacteria). The SBR trait however, of inverting the first two sequences, means that all of the carbon in the influent sewage is primarily available for denitrification. This includes all of the RBD COD, although it is appreciated that other than the first (and perhaps a portion of the second) day after fresh sewage has replenished the feed bucket, most of the RBD fraction of the sewage would have disappeared. Upon entering the reactor, unless there is a large amount of carbon (specifically RBD COD) available in the influent, practically all of it will be utilized by denitrifying bacteria and none will be available for storage by Bio-P organisms. Several researchers have suggested different values of COD utilized / mg of nitrate reduced. Ekama et al. (1984) has estimated the amount of RBD in a sewage by assuming that every mg of nitrate reduced by RBD carbon, utilizes 8.6 mg of the carbon for synthesis and energy production (U.S. EPA (1987)). Rabinowitz (1985), in a series of acetate fed batch experiments derived a rate of 3.60 mg COD / mg N03-N, a value less than one half of the value quoted above. In fact, this value is very close to the theoretical (stoichiometric) value for acetate (3.53 mg COD/mg N03-N) as calculated by McCarty et al. (1969). Whichever method is used, it is apparent that a considerable fraction of the influent carbon would be utilized for denitrification just because of the order of sequences in the SBR. At the full-scale level there is much less of a problem, since fresh feed is available on a daily basis. At the laboratory scale however, the SBR characteristic of inverting the two unaerated sequences (as it relates to the quantity and partitioning of carbon), can be accommodated in one of several ways. Manning and Irvine (1985) have circumvented the difficulty by using synthetic feed (not seeded with microorganisms and therefore not subject to substantial COD decay), prepared daily at the desired COD/TKN ratio. In their case, using SBRs on a 8 hour cycle, they used a relatively low COD/TKN ratio of 7.5:1, but were still able to reduce the ortho-P from 13 mg/L to 0.5 mg/L. The other method of ensuring enough RBD carbon, is the approach utilized in this research. As demonstrated, it involves artificially adding substrate when the denitrification reaction is suspected (Fixed-Time) or known (Real-Time) to be complete. This procedure operates from the premise that none of the influent carbon will be available for Bio-P carbon storage. However, as already seen in this analysis, the fluctuation in the carbon content when using real sewage still influences the operation of the SBRs significantly. On days when there is fresh feed available, denitrification happens quickly, often foiling the attempt by the Real-Time reactor to trap the nitrate breakpoint. During subsequent cycles, when the influent carbon content is low, denitrification likely occurs using carbon generated through endogenous reactions, much like the AASD set of experiments. On these days, the delay in the nitrate breakpoint clashes with the reactor's addition of acetate (especially the Fixed-Time reactor). In such cases, the acetate is used partially for denitrification and partially for Bio-P carbon storage. Thus, poor P uptake in the aerobic zone is observed and, as mentioned, this often degenerates into an oscillating high/low behaviour exhibited by the effluent P. A second critical parameter that must be in balance is the Food:Microorganism (F:M) ratio in the reactor. Many researchers consider the F:M ratio as having a major influence on the biological nutrient removal process (in terms of its operation and performance (Krichten et al. (1985), Tracy and Flammino (1987)). Of the SBR studies reviewed for this research, Manning and Irvine (1985) used an F:M ratio of 0.26 g COD/g VSS/d while Irvine et al. (1985) reported successful full-scale P removal at the Culver Indiana SBR, with F:M ratios of 0.16 and 0.42 kg BOD5/kg MLVSS/d. Maier et al. (1984), in a series of pilot plant experiments, observed that the rate of phosphorus uptake/unit of MLVSS decreased by a factor of 2.6, as the F:M ratio declined from 0.2 to 0.1 kg TBOD/kg MLVSS/day. Tracy and Flammino (1985) reported bench-scale results in which the TBOD:TP ratio was held constant at 16:1, while the F:M ratio was decreased from 0.44 to 0.24 TBOD/kg MLVSS/d. They observed that the rate of phosphorus uptake in the aerobic zone decreased by a factor of three. McCartney and Oleszkiewicz (1988) used synthetic feed in lab scale SBRs, but were unable to achieve excess P removal. They hypothesized that, among other reasons, their F:M ratio (not stated in the paper) was too low to get good P removal. The lack of uniformity in both the way of reporting the F:M ratio and in the operation and type of Bio-P systems for which results are available, make comparisons with this research difficult. As evidenced by the preceding discussion however, there is little doubt that the F:M ratio is an important parameter and can considerably influence the propensity for P removal in a system. Most wastewater treatment systems are designed to be operated at steady-state. In this research however, the mass of solids in the reactor declined dramatically over the course of the run. The lack of aeration control may have contributed to an over-oxidized biomass (loss in solids); however, since little solids were lost in the effluent, it is clear that the major cause of this was a lack of bacterial growth inside the reactor. Thus, insofar as the solids were concerned, steady-state conditions were not achieved. Comeau (1989) operated SBRs in a similar manner using an 8 hour cycle and a 20 day SRT. His objective was to characterize the addition of various levels of acetate on PHA storage. The results for the 30 mg/1 acetate addition were very similar to the results from this research, in that both release and uptake occurred to about the same levels observed in this study. No excess removal of phosphorus was observed for any of the acetate additions (0, 15, 30, 45 mg/L) and thus the effluent P levels were virtually the same as the influent values. He does comment however, both on the lack of aeration control and the lack of steady-state conditions; however, no time-series solids data is presented. As is evident in this research, the F:M ratio was constantly changing with time due to fluctuations in both the carbon content in the feed bucket and the decline in the solids in the reactor; thus, no calculations are presented for this analysis. Using the averages for the total COD and the MLVSS is invalid, and it does not reflect the reality of the trends experienced in the reactor. It is suspected however, that the lack of steady-state conditions influencing the F:M ratio, also contributed to the lack of excess phosphorus removal observed during the course of this research. 5.3 Evaluation of Reactors: Breakpoint Categories As is evident from the above analysis, during both runs the reactors failed to remove, for any reasonable length of time, a level of phosphorus that could be considered as "excess". Thus, the reactors cannot be compared on the basis of successful P removal. Moreover, the characteristic curve shape (i.e. the ideal ORP-time profile depicted in Figure 5.1) was never achieved, for either reactor, for any significant period of time. Therefore, a tabulation of deviations from an "indigenous" profile (due to spikes or otherwise) is not possible (as was done for the AASD set of experiments). In fact, no spikes of any kind were performed, due to the general lack of stability (both phosphorus related and ORP related) in the reactor. It is possible, however, to outline a protocol for evaluating the reactors, which could be followed in the event that excess biological phosphorus removal is regularly achieved. This is done by categorizing the nitrate breakpoints into distinct groupings and tabulating the number of occurrences of each kind. For example, since a key criterion for successful Bio-P removal involves the elimination of nitrates from the anaerobic sequence, a reactor operating under Fixed-Time conditions may prematurely implement the addition of VFAs, before all nitrates have been reduced by denitrifying bacteria. Thus, a proportion (or all) of the acetate may be used to reduce nitrates, rather than being sequestered into carbon reserves by Bio-P organisms. This has already been observed in Figures 5.5 and 5.6. Partitioning of the acetate between denitrifiers and Bio-P microbes represents a "failure" category, since, in essence, the objective of VFA addition has been partially thwarted. Such a category can be recognized by a detailed examination of the time-of-occurrence of the breakpoints. If the nitrate breakpoint occurs either simultaneously with or after the acetate addition (i.e greater than or equal to), it defeats the purpose of VFA addition since all or a portion of the acetate is being used to reduce nitrates, rendering it unavailable for the exclusive use of micro-organisms capable of excess P removal. Categorizing the nitrate breakpoints into different groupings is illustrated in Figures 5.29 and 5.30. Figure 5.29 shows a detailed snapshot over two days, itemizing the breakpoints into those that occurred before the addition of acetate (and thus the acetate was used solely for carbon storage), those that were directly attributable to (i.e induced by) the addition of acetate, and those that occurred after VFA addition and thus had a portion of (or all of) the acetate utilized for denitrification. As implied in the previous paragraph, the latter two categories can be considered as one category. A longer snapshot in time is presented in Figure 5.30. This plots (over 8 days) the length of time taken to denitrify in the Fixed-Time reactor, as measured by the length of time from the end of the FILL period to the nitrate breakpoint. Similar to the AASD experiments, a cyclical pattern (on a larger scale) develops, this time a function of the carbon content in the feed bucket. The dotted line represents the point of Fixed-Time addition of acetate (i.e. 1 hour and 25 minutes into the anoxic zone). Thus, those cycles which possess denitrification times below the line are operating in true Bio-P fashion, that is, having acetate additions which comply with the stated objective (i.e. used solely for carbon storage). Those cycles greater than 188 I a. S o 60 - 40 - 20 - 0 - -20 - -40 - -60 - -80 - -100 - -120 - -140 - -160 - -180 - -200 - -220 - -240 - Knee < VFA \ Add 1 \ i Knee > VFA " I 5 I \ ^T"" "• r—' | 2lYT Add Point of VFA Addition FTRCTR J \ « ~4\ i i / ^ - — - ^ ^ ^ ^ ^ ^ ^ • ^ ^ ^ s** _^^^^*~ Mf Bio-P #1 If// Fbted-TIme Reactor //// ORP Profile 0RP1b lllj March 18-19/91 III lllll \m Cycle Note / 1 VFAs Used for Bio-P / 2 VFAs Probably Cause I Oenitrtflcation 3-6 VFAs Used for Denitrification Time (Hrs) Figure 5.29 Breakpoints Classified According to Acetate Use Figure 5.30 Nine Day Track of Denitrification Time or equal to the line are "failing" insofar as the purpose of acetate addition is concerned, since the acetate is not being exclusively stored in carbon reserves. As can be seen, in this particular period, for a full 44 % of the time, the acetate was not used solely for carbon storage. Other breakpoint categories involve the Incomplete Denitrification failure previously shown in Figure 5.12. There did not seem to be a corresponding Incomplete Nitrification failure, as measured by the NH3 level in the effluent. This is due to the large D.O. values observed during reactor aeration. One further "failure" category is the "Rapid Denitrification" pattern previously documented in Figure 5.2 and which occurs when denitrification happens immediately after the FILL period has ended. This category is a "failure" insofar as the Real-Time reactor is concerned, since it is unable to detect the breakpoint, upon which proper acetate addition is contingent. It is not a "failure" from the Fixed-Time reactor perspective, however, since the acetate is added regardless of when the knee occurs. Another "failure" particular to Real-Time control is "Curve Distortion" which makes the true knee impossible to ascertain. Since Real-Time control hinges upon clean reproducible curves, any time there is distortion, the software has difficulty in detecting the breakpoint. For example, Figure 5.31 depicts the curve generated when the decanting solenoid failed, by remaining open after the DRAW/IDLE period had terminated. Thus, during the next FILL period, the incoming sewage mixed with the settled 190 200 150 - 100 - 50 Third Cycle 5:00pm - 1:00am -50 - -100 - -150 - -200 - Nitrate Breakpoint First Cycle 1:00am • 9:00am -250 Bio-P #1 Real-Time Reactor Profile Saturday March/30/91 Profile ORP2c Second Cycle 9:00am - 5:00pm Solenoid Fails and Decants One Half the Solids Time (Hrs) Figure 5.31 Disruption of Reactor Due to Solenoid Failure reactor contents and then immediately exited the reactor, carrying half the solids with it. Thus, the ORP probes measured the contents of a reactor that was much diluted. In Figure 5.32, the profile is shown which results from a mixer dislodging (allowing the reactor contents to settle). In this particular figure, the ORP probe measured the value obtained in the clarified supernatant, rather than from a reactor that was uniformly mixed. The final breakpoint categories can be considered as "success" categories, in the sense that the purpose of acetate addition (to an SBR operating in Bio-P fashion) is being realized. For the Fixed-Time reactor, this translates into the breakpoint occurring well before the addition of acetate (1 hour and 25 minutes). For the Real-Time reactor, it represents a sharp, detectable breakpoint which can be used to trigger the release of acetate to the bulk liquid. Tables 5.5 and 5.6 tabulate the number of occurrences (for both runs) of each type of breakpoint category and tallies those considered to be failures for each reactor. The total number of cycles in each run should theoretically be 120 (i.e. 40 days x 3 cycles/day); however, a few days were disregarded in each run due to power failures (longer than the UPS back-up capability) and days in which the reactor operation was momentarily halted in order to download the data. As can be seen, the tables indicate a rather high percentage (40-70 %) of failures for both reactors. No conclusions about the relative performance of the reactors can 192 100 - 50 - Mixer Failure @ 920 am ORP2c Profile Measuring Clarified Liquid ORP Value Second Cycle 9:00am - 5:00pm Mixer Reconnected 11:45 am No Observable Nitrate Breakpoint Bio-P #2 Real-Time Reactor Profile Sunday April/28/91 Collapse of Mixer First Cycle 1:00am - 9:00am Time (Hrs) Figure 5.32 Disruption of Reactor Due to Mixer Failure Table 5.5 Breakpoint Classification Categories: Bio-P#1 Breakpoint classification Category Bio-P*l Fixed-Time Reactor Breakpoint < VFA Addition Failure - Breakpoint > VFA Addition Failure - Incomplete Denitrification Rapid Denitrification - No Breakpoint Fixed-Time Failure Percentage = 54 % Real-Time Reactor Sharp Detectable Breakpoint Failure - Breakpoint = VFA Addition Failure - Incomplete Denitrification Failure - Rapid Denitrification Failure - Curve Distortion Real-Time Failure Percentage = 41 % # of Cycles 51 56 7 4 118 69 7 11 25 6 118 % of Cycles 43 % 48 % 6 % 3 % 100 % 59 % 6 % 9 % 21 % 5 % 100 % Table 5.6 Breakpoint Classification Categories: Bio-P#2 Breakpoint Classification Category Bio-P*2 Fixed-Time Reactor Breakpoint < VFA Addition Failure - Breakpoint > VFA Addition Failure - Incomplete Denitrification Rapid Denitrification - No Breakpoint Fixed-Time Failure Percentage = 61 % Real-Time Reactor Sharp Detectable Breakpoint Failure - Breakpoint = VFA Addition Failure - Incomplete Denitrification Failure - Rapid Denitrification Failure - Curve Distortion Real-Time Failure Percentage = 71 % # of Cycles 7 67 3 38 115 33 35 4 37 6 115 % of Cycles 6 % 58 % 3 % 33 % 100 % 29 % 30 % 4 % 32 % 5 % 100 % 194 be drawn from these results, since the purpose of this exercise was merely to illustrate one aspect of the protocol that would be followed in evaluating the performance of the reactors. Perhaps the only comment that can be made is a relativistic one, in terms of the difference between Bio-P*l and Bio-P*2. The generally weaker sewage of Bio-P*2 is likely the major reason behind the greater number of failures (30%) in the "Breakpoint = VFA" category, as compared to Bio-P*l (6 %) . In this case it seems reasonable to suggest that weaker sewage directly caused a greater proportion of times that acetate was used to directly induce the breakpoint. To summarize, the above method involves categorizing the breakpoints into distinct groupings based upon whether they assist or hinder the purpose of VFA addition in SBR Bio-P removal. This would be incorporated into a larger protocol for evaluating a system successfully removing phosphorus. That is, the above analysis could be considered in conjunction with measurements of effluent ortho-P (presented as a time-series analysis), from a successfully operating Bio-P system. Graphically depicting the differences in effluent quality between a functional process (one in which ortho-P levels were consistently low and constant) and a non-functional process (one with either high or erratic P levels) would assist in deciding which system was the preferred one in terms of control stability. It is hoped, of course, that an ORP-driven system would be recognizable as the better alternative; however, more research is needed to substantiate this. 195 CHAPTER 6 CONCLUSIONS AND RECOMMENDATIONS 6.1 Conclusions Many of the traditional methods of controlling activated sludge plants (ex. F:M and SRT), use variables which are historical in nature, in the sense that they convey what has historically happened to the biomass. A system at steady-state can be effectively controlled by the proper application of such parameters. There exists a need however, to continue to investigate parameters which can rapidly assess the current status of the biomass, since, during transient conditions, the parameters mentioned above can not be evaluated rapidly enough. This research, therefore, has addressed the need for a process control strategy for biological wastewater treatment systems to be founded on a bacterial vision of the process scheme. In particular, the bacterial correlation with the relative change with time in oxidation-reduction potential has been explored. Specific conclusions particular to the operating strategies considered in this research, include the following: 1) There is a clear, distinct breakpoint in the ORP-time curve which can be definitively correlated with the disappearance of nitrates and can therefore be assumed to represent the point of complete denitrification. 2) The nitrate breakpoint has been observed to be reproducible from cycle to cycle, such that it can be reliably used for control purposes. In the majority of instances, it is sufficiently pronounced to be readily detected by a computer program, subject to proper instalment of the necessary interfacing equipment between the computer and the ORP probe. 3) For the AASD*1 operating strategy (FT - 3 hours air-on/3 hours air-off, RT - 3 hours air-on/nitrate-breakpoint-determined air-off) the reactors performed essentially the same in terms of solids degradation (15 % - 18 %) , depending upon the mass balance method used and the solids (TSS or VSS) considered. The Real-Time reactor seemed to perform slightly better (up to 3 %) in relation to nitrogen removal; however, this difference was deemed to be insubstantial with regards to forming conclusions. The phosphorus recorded an apparent increase of 6 %, which was not considered excessive, as other researchers using the same TP digestion technique have encountered errors of the same magnitude. 4) For the AASD#1 operating strategy, the reactors were subjected to spikes of hydrogen peroxide, sodium nitrate and ammonium chloride. For each reactor, the number of deviations from the "indigenous" curve shape were tabulated and considered as "failures", since they predominantly represented a failure to complete a biological reaction (i.e. either nitrification or denitrification). The Fixed-Time reactor "failed" 9.5 % of the time while the Real-Time reactor failed 5.3 % of the time. Thus, the Real-Time reactor under this strategy was considered to more readily accommodate disturbances to the system. 5) The AASD#2 operating strategy (FT - 3 hours each for air- on/air-off, RT - air-on the same time as the air-off (determined by the nitrate breakpoint), seemed to perform marginally better both in terms of solids removal (up to 4 %) and nitrogen removal (up to 6 %) . Again, these results are subject to some interpretation since replicate experiments were not performed due to the prohibitive workload involved. 6) The AASD#2 operating strategy was subjected to the same spikes as AASD*1; however, in this case, the reactors accommodated the stresses in a similar manner, when normalization (in terms of the number of cycles that had potential for failure) was taken into account. 7) Under the Bio-P experimental conditions investigated in this research, excess biological phosphorus removal was not observed for any significant period of time. This was attributed primarily to the lack of steady-state conditions and the declining strength of the influent carbon. 8) A screening protocol was developed which could aid in evaluating a Bio-P SBR should excess P removal be observed. It consists of categorizing the time-of-occurrences of the nitrate breakpoints according to whether they hinder or assist the purpose of acetate addition to reactors operating in a Bio-P SBR fashion. An example of the application of this protocol was demonstrated. 9) In summary, the Fixed-Time and Real-Time strategies represent two antithetical management approaches. Fixed-Time control strategies are based on rapidly antiguated knowledge of the process dynamics. From the bacterial vantage point, this represents wasted treatment potential and/or inefficient reactor operation. Real-Time control strategies, however, evaluate the 198 process dynamics vicariously, through the bacterial "eyes" of ORP. A process functioning at the micro-organism environmental level, in most cases, should be more versatile in its response to transient influent conditions, since it is operating more fully cognizant of the bacterial needs. 6.2 Recommendations The results from this research indicate a number of areas worthy of consideration for further research. They include the following possibilities. 1) A critical analysis of the current algorithm (Lawrence 1991), reveals that the breakpoint algorithmn can be represented by the following general equation... DELTA = {Xi+9 - Xj+5 - X{+4 - X,.} / 5 (6.1) where... Xi - any ORP value (i = 1 to 180). In some applications, this may not be enough points to detect the knee, and in such instances attention would have to be directed to a more robust design. 2) Many post-denitrification strategies use external carbon sources (such as methanol) for denitrification. These are added on a continual basis with no feedback as to whether the carbon is actually needed for that particular cycle. The ORP nitrate breakpoint could be used to trigger the addition of the carbon source on an "as-needed" basis, reflecting the fact that some cycles would have sufficient carbon available generated through endogenous reactions. Considerable savings in terms of the cost of methanol may result from a strategy which always ensured complete elimination of NOx, either through carbon generated 199 internally or carbon added externally. 3) None of the AASD strategies considered in this research examined vector reduction. Most digesters are subject to regulations which specify certain log kills (Class A, B, etc.) for pathogenic organism control. It would be worthwhile to compare aerobic digestion log kills with ORP controlled AASD log kills to see if there is a comparable reduction in pathogens. 4) As previously noted, the AASD ORP-time curve contains other distinctive features which show potential for control. In particular, the "dissolved oxygen breakpoint" seems to represent the point where the ammonia is reduced to a very low (if not zero) level. Thus, proceeding past this point may in effect be supplying air that is not needed (i.e. overaeration). A strategy could be formulated in which the air is cycled on and off according to detection of both breakpoints, one on other side of the cycle. A pulsating air strategy such as this may result in considerable savings of air while simultaneously ensuring nitrification / denitrification. 5) The AASD strategy could be used with different sludges, in particular high rate (short SRT) sludges, mixes of primary and secondary sludges, and industrial sludges to see if ORP control has a broader applicability. 6) Using the Bio-P screening protocol, acetate additions could be added on a sequential basis. If the nitrate breakpoint did not occur in a "reasonable" length of time, the acetate could be added in a two-stage process. The first (smaller) pulse could be used to eliminate any remaining nitrates and the second 200 (larger) addition could be used solely for carbon storage by Bio-P bacteria. This would always ensure maximum carbon storage/P release in the anaerobic sequence of the SBR, even when using weaker strength sewages. 7)The Bio-P process should be investigated again, perhaps at a larger scale (pilot scale) and most certainly at steady- state. It is felt that the pilot scale level would reduce the effect of some of the variability that surfaced during the operation of these lab-scale reactors. Most notably, the lack of aeration control might matter less at a larger scale and/or be eliminated with a more sophisticated control apparatus. Secondly, the declining strength of the influent carbon could be circumvented by direct additions of influent from the sewer line. It is appreciated that there would be some unique difficulties associated with this latter approach. Most noticeably a stronger sewage would increase the rapid denitrification "failures". 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AG = A G ° + RT l o d {red} |_{ox} (1) (2) (3) (4) Now... "The reduction of one mole of oxidant to its reduced form requires the passage of nF coulombs of electricity against a potential difference of E volts, so the electrical work done by the system at constant temperature and pressure is nEF joules. This is equal to the decrease in free energy of the system" (Eilbeck and Mattock, (1987)). The Gibbs Free Energy Equation A G = -nEF at Standard State A G ° = -nE°F Substituting (5) and (6) into (4) Gives.... -nEF = -nE°F + RT log| {red} {ox} Or. . E = - RT log {red} nF {ox} (5) (6) (?) (8) which is the Nernst Equation. 214 APPENDIX B Page Intracellular Redox and Energy Calculation 215 APPENDIX B Intracellular Redox and Energy Calculation A Oxygen as a Terminal Electron Acceptor Consider the oxygen terminal electron acceptor with E° adjusted to an E value associated with a pH of 7.0, T = 25°C) . °2(aq) + 4 H + + 4 e < = > 2H2° E° = + 1- 2 7 (Snoeyink & Jenkins, 1980) @ pH = 7 E = E° + .0592 log {H+}4 n E = 1.27 + .0592 log {10"7}4 4 E = 1.27 + (-.42) = 0.85 volts when coupled with... (Dyson, 1974, T = 25°C) NAD+ + H+ + 2e" <=> NADH E° = -0.32 § pH = 7 gives the equation 1/2 02(aq) + H+ + NADH <=> NAD+ + H20 and since A G = -nEF AG = -2(23000 calories)[(-0.32)-(0.85)] volts volts A G = -46000 x (-1.17) = -53,820 cal/mole = -53.8 kcal/mole B ATP The Free energy of hydrolysis of ATP is approximately - 7000 cal/mole and there are 3 ATP molecules generated in one pass of the ETC with oxygen as the terminal electron acceptor. Thus... Efficiency = (3)(7000) x 100 % = 39 % capture. 53820 C Oxidative Phosphorylation Generates 38 ATP and with potential glucose oxidation of 686,000 cal/mole. Efficiency = (38)(7000) x 100 % = 39 % efficiency 686000 APPENDIX C SOFTWARE FLOWCHARTS - AASD AND BIO-P Figure Page C.l AASD START-UP AND INITIALIZATION MODULE 217 C. 2 AASD SCAN AND PLOTTING MODULE 217 C. 3 AASD INTERACTIVE MODULE 218 C.4 AASD RESET MODULE - 1A - BOTH RCTRS FT - AIR ON 219 C.5 AASD RESET MODULE - IB - BOTH RCTRS FT - AIR OFF 219 C.6 AASD RESET MODULE - 2A(i) - RT CONTROL - AIR ON FT... 220 C.7 AASD RESET MODULE - 2A(ii) - RT CONTROL - AIR OFF FT. 220 C.8 AASD RESET MODULE - 2B(i) - RT CONTROL - AIR ON RT... 221 C.9 AASD RESET MODULE - 2B(ii) - RT CONTROL - AIR OFF RT. 221 C. 10 AASD CLOSURE STATEMENTS 222 C. 11 AASD READPROBE MODULE 222 C. 12 BIO-P START-UP AND INITIALIZATION MODULE 223 C. 13 BIO-P SCAN AND PLOTTING MODULE 223 C. 14 BIO-P INTERACTIVE MODULE 224 C.15 BIO-P VFA ADDITION TO REAL-TIME REACTOR MODULE 224 C.16 BREAKPOINT SUBROUTINE - MODULE 1 225 C.17 BREAKPOINT SUBROUTINE - MODULE 2 225 C.18 BREAKPOINT SUBROUTINE - MODULE 3 226 C.19 BREAKPOINT SUBROUTINE - MODULE 4 226 (STARTY INCLUDE: GLOBAL AEHOBIC-ANOXIC SLUDGE DIGESTION START-UP AND iNmAUZATraN MODULE Initializing Block SCAN - 0 ; SCANTIME - SCAN.TIME STARTUP - 0 ; FLAGLOOP - T FLAGDIFF - T; REALTIME - F FLAG.RT - F ; NrTHATE - F FLAGSCRN - F; RENEW - F STARTPT - 1 ; ENDPT - 180 PT - 1 : INITIALIZE A/D BOARD CALL (AIR ON) 'RELAYSWfTCH (FIXED TIME) RELAYSWITCH (REALTIME) RECORD AIR ON TIME AIRON.FT - T OPEN COMMENT FILE FOR STORING MESSAGES SCAN AND PLOTTING MODULE FIGURE C.1 AASD START-UP AND INITIALIZATION MODULE READPROBE MODULE IF SCAN - NUMSCANS FLAGLOOP -FELSE FLAGLOOP = T FIGURE C.2 AASD SCAN AND PLOTTING MODULE TEST KEYBOARD BUFFER FOR INPUT KCODE - JINKEY (Function) AASD INTERACTIVE MODULE FIGURE C.3 AASD INTERACTIVE MODULE 219 AASD RESET MODULE PART1A BOTH REACTORS FIXED TIME AIR-ON CALL (AIR OFF) 'RELAYSWTTCH(FT) RELAVSWrrCH (HT) AIRON.FT - F RECORD TIME OF AIR OFF FT FLAG.RT > F AIRON.RT = F RECORD TIME OF AIR OFF RT RESET MODULE 2A (!) RESET MODULE 1B CLOSURE STATEMENTS SCAN AND PLOTTING MODULE FIGURE C.4 AASD RESET MODULE - 1A - BOTH RCTRS FT - AIR ON INTERACTIVE MODULE / ^ - " 1 F \ ^ J / * ^ ^ F L A G . H T Z > s^ n^^ AASD RESET MODULE PART1B BOTH REACTORS FIXED TIME AIR-OFF ^ ^ IF ^ \ ' •"^AJHONJ-T^ 9 F l ( pni i TiMra ^ i / I F \ / A OFF FT \ F \ > - 3 H R S / t / CALL \ / (AIR ON) \ ^ /^RELAYSWTTCH (FT) N. / RELAYSVWTCH (RT) \ 1 AIRON.FT - T RECORD TIME OF AIR ON FT i RESET " MODULE 2A(i) RESET MODULE 1A CLOSURE STATEMENTS ' 1 SCAN AND PLOTTING MODULE FIGURE C.5 AASD RESET MODULE - 1B - BOTH RCTRS FT - AIR OFF 220 SCAN AND PLOTTING MODULE FIGURE C.6 AASD RESET MODULE - 2A(i) - RT CONTROL - AIR ON FT INTERACTIVE MODULE / ^ - ^ 1 F ^ - \ F y * ^ F L A G . H I ^ yS ^ 1 AASD RESET MODULE PART2A0I) 1RCTRFT 1RCTRRT AIR-OFF FTRCTR F ^ - \ T N . l - l ^ - ' f \ ( POLL TIMER ) / I F \ /"^ACH V > - 3 =FFT \ F HRS / / CALL \ . / (AIR ON) \ / RELAYSWTTCH (FT) \ ^ ' ' AIRON.FT - T RECORD TIME OF AIR ON FT i | RESET 1 MODULE 18 J RESET MODULE 2A(I) CLOSURE STATEMENTS ' ' SCAN AND PLOTTING MODULE FIGURE C.7 AASD RESET MODULE - 2A(ii) - RT CONTROL - AIR OFF FT AASD RESET MODULE PART2B(I) 1RCTRFT 1RCTRRT AIR-ON RTRCTR Nots: AASO#1 • Umit - 3 hours AASD#2-Umit- Calculated Time for Anoxic Period \ > -UMTT * / ~ M / CALL N. / (AIR OFF) \ REUYSWrrCH (RT) \ I I AIRON.RT - F RECORD TIME OF AIR OFF RT i RESET MOCXILE1A RESET MODULE 28(10 CLOSURE STATEMENTS SCAN AND PLOTTING MODULE FIGURE C.8 AASD RESET MODULE - 2B(i) - RT CONTROL - AIR ON RT AASD RESET MODULE PART2B(ii) 1 RCTRFT 1 RCTRRT AIR-OFF RTRCTR Note: MAXANOX Umit - 4 hours T CALL (AIR ON) RELAYSWrrCH (RT) AIRON.RT - T RECORD TIME OF AIR ON RT CALL (AIR ON) RELAYSWrTCH (RT) AIRON.RT - J RECORD TIME OF AIR ON RT SCAN AND PLOTTING MODULE NITRATE-F RENEW- F CLOSURE STATEMENTS RESET MODULE 1B RESET MODULE 2B(1) FIGURE C.9 AASD RESET MODULE - 2B(ii) - RT CONTROL - AIR OFF RT 222 RESET MODULE AASD CLOSURE STATEMENTS RON • \ ) FLAGLCOP - T ' F T - FT + 1 t ^ ^  F  ^ \ \ ^ FT-181 T [ F PT-1 I T ^-""CALL \ . / ^ AXES ' SCAN AND PLOTTING MODULE FIGURE C.10 AASD CLOSURE STATEMENTS SCAN AND PLOTTING MODULE * SCAN-SCAN + 1 PRODUCE DATA ARRAY ADDRESSES SEGMENT - VARSEG(MVOLTS(0,SCAN)) OFFSET - VARPTR(MVOLTS(0,SCAN)) FLAGLOOP - F S C A N - 0 AASD READPROBE MODULE - H STOP FIGURE C.11 AASD READPROBE MODULE 223 INCLUDE: GLOBAL BIOLOGICAL PHOSPHORUS REMOVAL v START-UP AND \ INITIALIZATION \ MODULE Initializing Block SCAN = 0 ; SCANTIME = SCAN.TIME STARTUP = 0 ; FLAGLOOP = T FLAGDIFF « T; VFAPass = 0 VFAPump = F ; NITRATE = F FLAGSCRN = F ; RENEW » F FT = 1;STARTPT = 1;ENDPT= 180 Acetate = F; INITIALIZE A/D BOARD CHECK TIME FOR START OF ANOXIC PERIODS @ 1:10 am @ 9:10 am @ 5:10 pm RECORD TIME ANOXIC PERIOD STARTS OPEN COMMENT FILE FOR STORING MESSAGES SCAN AND PLOTTING MODULE FIGURE C.12 BIO-P START-UP AND INITIALIZATION MODULE START-UP AND INITIALIZATION MODULE VFA ADDITION MODULE [CLOSURE] FLAGLOOP = T •(TIMER ON/INCR BIO-P SCAN AND PLOTTING MODULE CALL PLOT READPROBE MODULE IF SCAN = NUMSCANS FLAGLOOP = F ELSE FLAGLOOP = T INTERACTIVE MODULE FIGURE C.13 BIO-P SCAN AND PLOTTING MODULE 224 SCAN AND PLOTTING MODULE TEST KEYBOARD BUFFER FOR INPUT KCODE = JINKEY (Function) ESC NONSENSE IF \ _ INPUT KCODE SELECT |  F BIO-P INTERACTIVE MODULE GRAPHICS OFF FLAGSCRN = F VFA ADDITION MODULE FIGURE C.14 BIO-P INTERACTIVE MODULE Note: LIMIT = 2 hours 42 minutes T VFAPASS = VFAPASS + 1 x  CALL ACETATE ON RELAYSWrTCH (RT) VFAPUMP = T RECORD TIME OF PUMP ON RENEW = T VFAPUMP = F VFAPASS = 0 ACETATE = T SCAN AND I PLOTTING I MODULE CLOSURE STATEMENTS CALL ACETATE OFF RELAYSWITCH (RT) FIGURE C.15 BIO-P VFA ADDITION TO REAL-TIME REACTOR MODULE 225 AASD RESET MODULE 2B (ii) OR BIO-P VFA ADDITION MODULE BREAKPOINT SUBROUTINE MODULE 2 BREAKPOINT SUBROUTINE MODULE 4 BREAKPOINT SUBROUTINE MODULE 3 FIGURE C.16 BREAKPOINT SUBROUTINE - MODULE 1 BREAKPOINT SUBROUTINE MODULE 1 AASD RESET MODULE 2B(ii) OR BIO-P VFA ADDITION MODULE BREAKPOINT SUBROUTINE MODULE 2 RINGNUM = 1 RING(RINGNUM) = SUM/RINGSIZE RRSTRING = RING(RINGNUM) FIGURE C.17 BREAKPOINT SUBROUTINE - MODULE 2 BREAKPOINT SUBROUTINE MODULE 1 AASD RESET MODULE 2B(ii) OR BIO-P VFA ADDITION MODULE RINGNUM = RINGNUM + 1 SUM = SUM - DORP(LOWBOUND) + DORP(PT) RING(RINGNUM) = SUM/RINGSIZE BREAKPOINT SUBROUTINE MODULE 3 SEARCH = T LASTRING = RING(RINGNUM) DIFFRING = LASTRING-FIRSTRING KNEEA,BORC = T KNEECOUNT = KNEECOUNT + 1 FIGURE C.18 BREAKPOINT SUBROUTINE - MODULE 3 BREAKPOINT SUBROUTINE MODULE 1 AASD RESET MODULE 2B(ii) OR BIO-P VFA ADDITION MODULE RINGNUM = RINGNUM + 1 SUM = SUM - DORP(LOWBOUND) + DORP(PT) RING(RINGNUM) = SUM/RINGSIZE FIRSTRING = RING(RINGNUM - RINGSIZE + 1) LASTRING = RING(RINGNUM) DIFFRING = LASTRING - FIRSTRING NITRATE = T BREAKPOINT SUBROUTINE MODULE 4 KNEEA,BORC = T KNEECOUNT = KNEECOUNT + 1 FIGURE C.19 BREAKPOINT SUBROUTINE - MODULE 4 APPENDIX D SOFTWARE CODE - AASD'l, AASD*2 AND BIO-P Program Name Page GLOBAL. BI - AASD#1, AASD*2, BIO-P 228 AEROBIC-ANOXIC SLUDGE DIGESTION - Main Program Start-Up and Initialization Module 229 Scan and Plotting Module 230 Readprobe Module 230 Interactive Module 231 Reset Module: Parti - Both RCTRS FT 232 Reset Module: Part2 - 1 RCTR FT/ 1 RCTR RT -AASD*1 233 Reset Module: Part2 - 1 RCTR FT/ 1 RCTR RT - AASD#2. . . 235 BIOLOGICAL PHOSPHORUS REMOVAL - Main Program Start-Up and Initialization Module 237 Scan and Plotting Module 238 Interactive Module 239 VFA Addition to RT RCTR Module 240 ReadprobeModule 241 INFORM.BAS AASD#1 242 AASD#2 242 BIOP 242 FILENAME. BAS 243 REFRESH. BAS 243 INITREL.BAS 244 RELAY. BAS 244 AXES. BAS 245 PAXIS.BAS 245 SCANS. BAS 246 DIFF.BAS AASD#1/AASD#2 247 BIO-P 247 ORPSCRN.BAS 248 WRITING. BAS 248 TRANSFER. BAS 249 PLOT. BAS 249 LAYOUT.BAS AASD#1/AASD#2 250 BIO-P 250 UPDATE.BAS 251 TYPROBE.BAS 251 JINKEY.BAS 251 BREAKPT.BAS AASD*1/AASD#2 252 B I O - P 2 5 5 RTout$, Commout$, FTnum, RTnum, Commnum) / GLOBAL.Bl DEFINT A-Z ' Declaration of Subroutines- DECLARE SUB INFORM () DECLARE SUB RELAYSWITCH (Relaynum%) DECLARE SUB INITRELAYS () DECLARE SUB FILENAME (FTout$, DECLARE SUB REFRESH (Probe$) DECLARE SUB ORPSCRN () DECLARE SUB AXES () DECLARE SUB PAXIS () DECLARE SUB SCANS (SCAN, Ft) DECLARE SUB DIFF (Flagdiff, Pt) DECLARE SUB WRITING (Pt, FToutS, RTout$, FTnum, RTnum) DECLARE SUB TRANSFER (ProbeID$, Pt) DECLARE SUB PLOT (Pt) DECLARE SUB BREAKPT (Commnum, Pt, Nitrate, Renew) DECLARE SUB LAYOUT () DECLARE SUB UPDATE (Pt) ' Declaration of Functions DECLARE FUNCTION TYPROBE$ (Probe$) DECLARE FUNCTION jinkey% () DECLARE FUNCTION getscanl% (iobase%, first%, last%, BYVAL segaddr%, BYVAL offaddr*) ' Declaration of Constants 'The scanning time is 2 seconds. 'The number of channels to be scanned. 'Number of scans in two minute interval. 'For dimensioning purposes. 'Currently a Four Hours Maximum Anoxic Limit 'For <Yes> decision in selecting other probes. 'For <No> decision finished viewing probes. 'For escaping from program. 'The first channel - lower bound. 'The last channel - upper bound. 'The base address of the A/D board. 'The base address of the relay board. 'Mostly used for flag settings. 'Mostly used for flag settings. 'The Width of the Ring. 'The number of Rings in the Buffer. 'The difference in slope between the first and last 'rings of the Ringbuffer for the Real Time 'ORP Probes. 'Safety Factor to allow stability after air ceases. ' Dimensioning of Arrays DIM MVolts(NUM.CHANNELS, NUM.SCANS) DIM ORPla(NUM.PTS) AS SINGLE, ORPlb(NUM.PTS) AS SINGLE DIM ORPlc(NUM.PTS) AS SINGLE, 0RP2a(NUM.PTS) AS SINGLE DIM 0RP2b(NUM.PTS) AS SINGLE, 0RP2c(NUM.PTS) AS SINGLE DIM DOxl(NUM.PTS) AS SINGLE, DOx2(NUM.PTS) AS SINGLE DIM ORP(NUM.PTS) ~ "" DORPlb(NUM.PTS) AS SINGLE DORP2a(NUM.PTS) AS SINGLE DORP2c(NUM.PTS) AS SINGLE RING2b(NUM.PTS) AS SINGLE CONST SCAN.TIME = 2 CONST NUM.CHANNELS = 1 6 CONST NUM.SCANS = 60 CONST NUM.PTS = 1 8 1 CONST MAX.ANOX = 14400 CONST KY.LY = SH79 CONST KY.LN = &H6E CONST KY.ESC = SH1B CONST chan0% = 0 CONST chanl5% = 15 CONST baseaddr% = &H220 CONST ioaddr% = &H300 CONST FALSE = 0 CONST TRUE = 1 CONST RINGSIZE CONST NUMRINGS CONST DELTA2A1 CONST DELTA2B! CONST DELTA2C! CONST MAXAVOID 5 5 -1. -1. -1. 15 25 25 25 DIM DORPla(NUM.PTS) DIM DORPlc(NUM.PTS) DIM DORP2b(NUM.PTS) DIM RING2a(NUM.PTS) DIM RING2c(NUM.PTS) AS SINGLE, AS SINGLE, AS SINGLE, AS SINGLE, AS SINGLE -Variables shared between Modules COMMON SHARED 0RPla() AS SINGLE, 0RPlb() AS SINGLE, 0RPlC() AS SINGLE COMMON SHARED 0RP2a() AS SINGLE, ORP2b() AS SINGLE, 0RP2c() AS SINGLE COMMON SHARED DOxl() AS SINGLE, D0x2() AS SINGLE COMMON SHARED 0RP(), MVolts() COMMON SHARED DORPla() AS SINGLE, DORPlb() AS SINGLE, AS SINGLE, DORP2b() AS SINGLE, AS SINGLE, RING2b() AS SINGLE, Endpt, ONOFFmap&, DigitOl, Digit02, Digit21, Digit22 Digit42, Digit61, Digit52, Digit3, Digit4 COMMON SHARED DORP2a() COMMON SHARED RING2a() COMMON SHARED Startpt, COMMON SHARED Digit41, DORPlCf) AS SINGLE DORP2c() AS SINGLE RING2c() AS SINGLE AASD1BAS and AASD2.BAS DEFINT A-Z STARTUP AND INITIALIZATION MODULE 'This module introduces the user to the mechanics of the program, initializes 'some parameters, and declares global parameters. '$INCLUDE: 'GLOBAL.BI' CLS CALL INFORM 'Call the information for the program mechanics. CALL FILENAME(FTout$, RTout$, CommoutS, FTnum, RTnum, Commnum)'Set disk Files Runprompt: LOCATE 21, 15: INPUT ; "Do you want to run the program? (Y/N) ", RAns$ RAns$ = UCASE$(RAns$) IF RAns$ = "Y" THEN GOTO Initialize ELSEIF RAns$ = "N" THEN GOTO Theend ELSE GOTO Runprompt END IF Initialize: SCAN = 0 Scantime = SCAN.TIME OUT baseaddr%, &H0 FOR x = 1 TO 100: NEXT x i = INP(baseaddr% + 1) i = INP(baseaddr% + 1) CALL INITRELAYS Startup = 0 Flagloop = TRUE Flagdiff = TRUE Realtime = FALSE Flag.RT = FALSE Nitrate = FALSE Renew = FALSE Flagscrn = FALSE Pt = 1 Startpt = 1 Endpt =180 CALL LAYOUT CALL AXES 'Set the Scan counter to zero to start the scans. 'The Scan time is currently every 2 seconds. 'Initialize the DT2814 A/D Board 'as per the DT2814 manual on pg. 5-9 'Initialize the relay board - set all relays off. 'Used to control the Scanning Loop 'Flag for breaking out of and into Scanning Loop. 'Flag to signify no preceeding point in Diff Sub. 'Initially no Real Time Control of Reactor # 2 'Real-time indicated - wait for anoxic cycle 'No Nitrate Breakpoint Detected as of yet. 'Flag used to clear/reset Breakpt Sub variables. 'Flag indicating whether graphics is invoked 'Assign initial point of the start of cycle. 'Storage of initial Pt value. 'There are 180 points in a Six Hour Cycle. 'Layout the Text mode information. 'Calculate the relevant time axis. Relaynum% = 0: CALL RELAYSWITCH(Relaynum%) Relaynum% = 1: CALL RELAYSWITCH(Relaynum%) StartAer.FTS = TIMER AirOn.FT = TRUE OPEN CommoutS FOR APPEND AS #Commnum PRINT #Commnum, "AirFT On at "; TIMES PRINT #Commnum, "AirRT On at "; TIMES 'Air on for 3 hours of Aeration 'Air.FT is switched on 'Air.RT is switched on 'Poll the TIMER Function 'Write to the comment file 230 SCAN AND PLOTTING MODULE This module scans the ORP probes every 2 seconds and then every 2 minutes an average for each probe is calculated and plotted if graphics is invoked else an update is written to the screen in text mode. Scanning: ON TIMER(Scantime) GOSUB Readprobe 'Every 2 sec. go to the Readprobe Module TIMER ON 'Enable On Timer event-handling trapping routine DO 'Loop enclosing the entire program - to exit press <Escape> IF Flagloop = FALSE THEN 'Break out of the Scanning Loop TIMER STOP CALL DIFF(Flagdiff, Pt) 'Calculate the First Difference Flagdiff = FALSE 'Now Preceeding Pts are available Datecheck = VAL(MIDS(DATES, 4, 2)) 'Perform Date check on the Data IF Datecheck <> FTnum THEN 'If past midnight (ie. new day) CLOSE fCommnum 'Close comment file - ooen data CALL FILENAME(FTout$, RToutS, Commout$, FTnum, RTnum, Commnumj 'file OPEN CommoutS FOR APPEND AS #Commnum 'Open new comment file END IF CALL WRITING(Pt, FToutS, RTout$, FTnum, RTnum) 'Write data to disk IF Flagscrn = FALSE THEN CALL UPDATE(Pt) 'Update the information screen IF Flagscrn =» TRUE THEN CALL TRANSFER(ProbelDS, Pt) 'Transfer the array of points CALL PLOT(Pt) 'Plot history of points to present END IF READPROBE MODULE 'This module does the actual reading of the probes by calling the SCAN Sub Readprobe: SCAN - SCAN + 1 'Increment the SCAN Counter LOCATE 23, 42: PRINT USING "###"; SCAN segment% = VARSEG(MVolts(0, SCAN)) 'Produce the requisite FAR offset% - VARPTR(MVolts(0, SCAN)) 'Pointer to the data array 'Call the function returning an error code errnum% = getscanl%(baseaddr%, chan0%, chanl5%, segment%, offset%) IF errnum% <> 0 THEN PRINT #Commnum, "Getscan returned an error code at "; TIMES GOTO Theend END IF CALL SCANS(SCAN, Pt) 'Call the SCAN Subroutine IF SCAN =• NUM.SCANS THEN '60 Scans (2 min) elapsed SCAN = 0 Flagloop =* FALSE 'Break out of scanning loop END IF RETURN INTERACTIVE MODULE This module allows the user to interact with the process allowing him to select any of the probes which he desires to observe on a real-time basis. kcode = jinkey% 'Test for Keystroke in the Keyboard buffer. IF kcode THEN 'Determine what the keystroke is. SELECT CASE kcode CASE KY.ESC EXIT DO CASE KY.LY GOTO Whichprobe 'Which probe has been selected. Whichprobe: LOCATE 23, 48: INPUT "Which Probe? (Letter)"; Probe$ Probe$ = UCASE$(Probe$) IF Probe$ = "A" OR Probe$ = "B" OR Probe$ = "C" THEN GOTO RTprompt IF Probe$ = "D" OR Probe$ = "E" OR Probe$ = "F" THEN GOTO RTprompt ELSE GOTO Whichprobe END IF RTprompt: IF Realtime = FALSE THEN 'Interested in Real Time Control? LOCATE 23, 48: INPUT "Real-time control RCTR 2? (Y)"; Ans.RTS Ans.RT$ = UCASE$(Ans.RT$) IF Ans.RT$ = "Y" THEN Realtime = TRUE END IF SCREEN 3 'For Hercules Graphics capabilities Flagscrn = TRUE 'Do not overlay text mode on graphics CALL REFRESH(Probe$) 'Refresh the screen ProbeID$ - TYPROBE$(Probe$) 'Identify the Selected probe CALL TRANSFER(ProbeID$, Pt) 'Transfer the array of points CALL PLOT(Pt) 'Plot history of points to present LOCATE 23, 27: PRINT "Scan Number - " CASE KY.LN SCREEN 0 'Turn off Hercules Graphics Flagscrn = FALSE 'Invoke Text mode again CALL LAYOUT 'Layout the text information CALL UPDATE(Pt) 'Update the screen information CASE ELSE 'Do nothing END SELECT 'Closes Select Case kcode Structure. END IF 'Closes IF kcode Decision Block. RESET MODULE: Part 1 - Both Reactors Fixed time This module resets some flags to break out of loops at the appropriate times. IF Flag.RT = FALSE THEN IF AirOn.FT = TRUE THEN FinishAer.FTS = TIMER 'Real time not implemented yet. — Part la Air On 'Check for finish of 3 hr aeration period 'Poll the TIMER Function 'Check if 3 hr air on period overlaps into next day IF FinishAer.FTS < 10920 AND StartAer.FTS >= 75480 THEN FinishAer.FTS = FinishAer.FTS + 86400 END IF IF (FinishAer.FTS - StartAer.FTS) >= 10800 THEN Relaynum% = 0: CALL RELAYSWITCH(Relaynum%) Relaynum% = 1: CALL RELAYSWITCH(Relaynum%) StartAnox.FTS = TIMER AirOn.FT = FALSE PRINT ICommnum, "AirFT Off at "; TIME$ PRINT #Commnum, "AirRT Off at "; TIME$ IF Realtime = TRUE THEN Flag.RT = TRUE StartAnox.RTS = TIMER AirOn.RT = FALSE PRINT #Commnum, "Real-Time started at "; TIME$ END IF 'Aerated for 3 hours 'Air.FT is switched off 'Air.RT is switched off 'Poll the TIMER Function 'Write to the comment file 'User wants Realtime control 'Avoid Part 1 - no Real Time 'Poll the TIMER Function END IF 'Closes 3 Hour Aeration Block END IF 'Closes If AirOn.FT = TRUE Part la Decision Block ' Part lb Air Off IF AirOn.FT = FALSE THEN 'Check for Finish of 3 hours air off period FinishAnox.FTS = TIMER 'Poll the TIMER Function 'Check if 3 hour air off period overlaps into next day IF FinishAnox.FTS < 10920 AND StartAnox.FTS >= 75480 THEN FinishAnox.FTS = FinishAnox.FTS + 86400 END IF IF (FinishAnox.FTS - StartAnox.FTS) >= 10800 THEN 'Anoxic for 3 hours Relaynum% = 0: CALL RELAYSWITCH(Relaynum%) 'Air.FT is switched on Relaynum% = 1: CALL RELAYSWITCH(Relaynum%) 'Air.RT is switched on StartAer.FTS = TIMER 'Poll the TIMER Function AirOn.FT = TRUE PRINT #Commnum, "AirFT On at "; TIME$ 'Write to the comment file PRINT #Commnum, "AirRT On at "; TIMES END IF 'Closes 3 hour Air Off Decision Block END IF 'Closes If AirOn.FT = FALSE Part lb Decision Block •Note: This is for the AASD#1 Program RESET MODULE: Part 2 - 1 RCTR Fixed Time / 1 RCTR Real time ELSEIF Flag.RT = TRUE THEN 'Real Time Control Implemented • Part 2a(i) - Fixed Time Air On IF AirOn.FT = TRUE THEN 'Check for Finish of 3 hour aeration period FinishAer.FTS = TIMER 'Poll the TIMER Function 'Check if 3 hr air on period overlaps into next day IF FinishAer.FTS < 10920 AND StartAer.FTS >= 75480 THEN FinishAer.FTS = FinishAer.FTS + 86400 END IF IF (FinishAer.FTS - StartAer.FTS) >= 10800 THEN 'Aerated for 3 hours Relaynum% = 0: CALL RELAYSWITCH(Relaynum%) 'Air.FT is switched off. StartAnox.FTS = TIMER 'Poll the TIMER Function AirOn.FT = FALSE PRINT Kommnum, "AirFT Off at "; TIMES 'Write to the comment file END IF END IF 'Closes If AirOn.FT = TRUE Part 2a(i) Decision Block ' Part 2a (ii) - Fixed Time Air Off IF AirOn.FT = FALSE THEN 'Check for finish of 3 hr air off period FinishAnox.FTS = TIMER 'Poll the TIMER Function 'Check if 3 hour air off period overlaps into next day IF FinishAnox.FTS < 10920 AND StartAnox.FTS >= 75480 THEN FinishAnox.FTS = FinishAnox.FTS + 86400 END IF IF (FinishAnox.FTS - StartAnox.FTS) >= 10800 THEN 'Anoxic for 3 hours Relaynum% = 0: CALL RELAYSWITCH(Relaynum%) 'Air.FT is switched on. StartAer.FTS = TIMER 'Poll the TIMER Function AirOn.FT => TRUE PRINT #Commnum, "AirFT On at "; TIMES 'Write to the comment file END IF END IF 'Closes If AirOn.FT = FALSE Part 2a(ii) Decision Block ' Part 2b (i) - Real Time Air On IF AirOn.RT = TRUE THEN 'Check for finish of 3 hour air on period FinishAer.RTS = TIMER 'Poll the TIMER Function 'Check if 3 hour air on period overlaps into next day IF FinishAer.RTS < 10920 AND StartAer.RTS >= 75480 THEN FinishAer.RTS = FinishAer.RTS + 86400 END IF IF (FinishAer.RTS - StartAer.RTS) >= 10800 THEN 'Aerated for 3 hours Relaynum% - 1: CALL RELAYSWITCH(Relaynum%) 'Air.RT is switched off. StartAnox.RTS = TIMER 'Poll the TIMER Function AirOn.RT =» FALSE PRINT #Commnum, "AirRT Off at •*; TIME$ 'Write to the comment file END IF END IF 'Closes If AirOn.RT = TRUE Part 2b(i) Decision Block / Part 2b (ii) - Real Time Air Off IF AirOn.RT = FALSE THEN 'Check for Finish of Air Off Period FinishAnox.RTS = TIMER 'Poll the TIMER Function 'Check if Maximum Anoxic limit overlaps into next day IF FinishAnox.RTS < MAX.ANOX AND StartAnox.RTS >= (86400 - MAX.ANOX) THEN FinishAnox.RTS = FinishAnox.RTS + 86400 END IF IF (FinishAnox.RTS - StartAnox.RTS) >= MAX.ANOX THEN 'Anoxic limit exceeded Relaynum% = 1: CALL RELAYSWITCH(Relaynum%) 'Air.RT is switched on. StartAer.RTS = TIMER 'Poll the TIMER Function AirOn.RT = TRUE PRINT #Commnum, "Nitrate knee NOT detected on "; DATE$; PRINT #Commnum, " AirRT activated at "; TIME$ Renew = TRUE 'Reset Breakpoint Subroutine CALL BREAKPT(Commnum, Pt, Nitrate, Renew) Renew = FALSE ELSE 'Search for Nitrate Breakpt CALL BREAKPT(Commnum, Pt, Nitrate, Renew) IF Nitrate = TRUE THEN Relaynum% = 1: CALL RELAYSWITCH(Relaynum%) 'Air.RT switched on. StartAer.RTS = TIMER 'Poll the TIMER Function AirOn.RT = TRUE PRINT #Commnum, "Nitrate knee detected on "; DATES; PRINT #Commnum, " AirRT activated at "; TIME$ Nitrate = FALSE Renew = TRUE 'Reset Breakpoint Subroutine CALL BREAKPT(Commnum, Pt, Nitrate, Renew) Renew = FALSE END IF 'Closes If Nitrate = TRUE Decision Block END IF 'Closes If Anoxic limit is > MAX.ANOX Decision Block END IF 'Closes If AirOn.RT = FALSE Part 2b(ii) Decision Block END IF 'Closes IF Flag.RT = FALSE Block - RESET MODULE ' Closure Statements TIMER ON 'Enable the On Timer trapping event-handling subroutine. Flagloop = TRUE 'Break back into the Scanning Loop. Pt = Pt + 1 'Increment point. IF Pt = 181 THEN 'Start of next 6 Hour Cycle Pt = 1 'Reset Pt to one CALL AXES 'Calculate the new time Axis END IF 'Closes IF Pt = 181 Decision Block. END IF 'Closes IF Flagloop = FALSE Block Scanning Loop LOOP WHILE Startup < 2 'Closes DO LOOP Structure. Theend: CLOSE #Commnum 'Close the Comment File ONOFFmaps = SHFFFF 'When exiting the program OUT (ioaddr%), ONOFFmapS 'turn off all the relay OUT (ioaddr% + 1), ONOFFmapS 'switches at both ports A and B CLS END 'Note: This is for the AASD#2 Program 235 ' RESET MODULE: Part 2 - 1 RCTR Fixed Time / 1 RCTR Real time ELSEIF Flag.RT = TRUE THEN 'Real Time Control Implemented ' Part 2a (i) - Fixed Time Air On IF AirOn.FT = TRUE THEN 'Check for Finish of 3 hour aeration period FinishAer.FTS = TIMER 'Poll the TIMER Function 'Check if 3 hr air on period overlaps into next day IF FinishAer.FTS < 10920 AND StartAer.FTS >= 75480 THEN FinishAer.FTS = FinishAer.FTS + 86400 END IF IF (FinishAer.FTS - StartAer.FTS) >= 10800 THEN 'Aerated for 3 hours Relaynum% = 0: CALL RELAYSWITCH(Relaynum%) 'Air.FT is switched off. StartAnox.FTS = TIMER 'Poll the TIMER Function AirOn.FT = FALSE PRINT #Commnum, "AirFT Off at "; TIMES 'Write to the comment file END IF END IF 'Closes If AirOn.FT = TRUE Part 2a(i) Decision Block '- Part 2a (ii) - Fixed Time Air Off IF AirOn.FT = FALSE THEN 'Check for finish of 3 hr air off period FinishAnox.FTS = TIMER 'Poll the TIMER Function 'Check if 3 hour air off period overlaps into next day IF FinishAnox.FTS < 10920 AND StartAnox.FTS >= 75480 THEN FinishAnox.FTS = FinishAnox.FTS + 86400 END IF IF (FinishAnox.FTS - StartAnox.FTS) >= 10800 THEN 'Anoxic for 3 hours Relaynum% = 0: CALL RELAYSWITCH(Relaynum%) 'Air.FT is switched on. StartAer.FTS = TIMER 'Poll the TIMER Function AirOn.FT = TRUE PRINT #Commnum, "AirFT On at '*; TIMES 'Write to the comment file END IF END IF 'Closes If AirOn.FT = FALSE Part 2a(ii) Decision Block ' Part 2b(i) - Real Time Air On IF AirOn.RT = TRUE THEN 'Check for finish of aeration period FinishAer.RTS = TIMER 'Poll the TIMER Function 'Check if aeration period overlaps into next day IF FinishAer.RTS < 10920 AND StartAer.RTS >= 75480 THEN FinishAer.RTS = FinishAer.RTS + 86400 END IF AerPeriod.RTS = FinishAer.RTS - StartAer.RTS 'Calculate Aeration Period IF (AerPeriod.RTS) >= AerLength.RTS THEN 'Aerated for anoxic period Relaynum% = 1: CALL RELAYSWITCH(Relaynum%) 'Air.RT is switched off. StartAnox.RTS = TIMER 'Poll the TIMER Function AirOn RT — FALSE PRINT #Commnum, "AirRT Off at "; TIMES 'Write to the comment file PRINT #Commnum, "RT Aeration Period for "; AerPeriod.RTS END IF END IF 'Closes If AirOn.RT = TRUE Part 2b(i) Decision Block / Part 2b(ii) - Real Time Air Off IF AirOn.RT = FALSE THEN 'Check for Finish of Air Off Period FinishAnox.RTS = TIMER 'Poll the TIMER Function 'Check if Maximum Anoxic limit overlaps into next day IF FinishAnox.RTS < MAX.ANOX AND StartAnox.RTS >= (86400 - MAX.ANOX) THEN FinishAnox.RTS = FinishAnox.RTS + 86400 END IF AnoxPeriod.RTS = FinishAnox.RTS - StartAnox.RTS IF (AnoxPeriod.RTS) >= MAX.ANOX THEN Relaynum% = 1: CALL RELAYSWITCH(Relaynum%) StartAer.RTS = TIMER AirOn.RT = TRUE AerLength.RTS = AnoxPeriod.RTS PRINT icommnum, "Nitrate knee NOT detected on PRINT #Commnum, " AirRT activated at "; TIME$ Renew = TRUE CALL BREAKPT(Commnum, Pt, Nitrate, Renew) Renew = FALSE 'Air off length of time 'Anoxic limit exceeded 'Air.RT is switched on. 'Poll the TIMER Function 'Assign aeration time DATE$; 'Reset Breakpoint Subroutine ELSE 'Search for Nitrate Breakpt CALL BREAKPT(Commnum, Pt, Nitrate, Renew) END IF END IF END IF IF Nitrate = TRUE THEN Relaynum% = 1: CALL RELAYSWITCH(Relaynum%) 'Air.RT switched on. StartAer.RTS = TIMER 'Poll the TIMER Function AirOn.RT = TRUE AerLength.RTS = AnoxPeriod.RTS 'Assign aeration time PRINT icommnum, "Nitrate knee detected on "; DATES; PRINT #Commnum, " AirRT activated at "; TIME$ Nitrate = FALSE Renew = TRUE 'Reset Breakpoint Subroutine CALL BREAKPT(Commnum, Pt, Nitrate, Renew) Renew = FALSE END IF 'Closes If Nitrate = TRUE Decision Block 'Closes If Anoxic limit is > MAX.ANOX Decision Block 'Closes If AirOn.RT = FALSE Part 2b(ii) Decision Block 'Closes IF Flag.RT = FALSE Block - RESET MODULE Closure Statements 'Enable the On Timer trapping event-handling subroutine. 'Break back into the Scanning Loop. 'Increment point. TIMER ON Flagloop = TRUE Pt = Pt + 1 IF Pt = 181 THEN Pt = 1 CALL AXES END IF END IF 'Start of next 6 Hour Cycle 'Reset Pt to one 'Calculate the new time Axis 'Closes IF Pt = 181 Decision Block. 'Closes IF Flagloop = FALSE Block Scanning Loop LOOP WHILE Startup < 2 Theend: CLOSE #Commnum ONOFFmapS = SHFFFF OUT (ioaddr%), ONOFFmapS OUT (ioaddr% + 1), ONOFFmapS CLS END 'Closes DO LOOP Structure. 'Close the Comment File 'When exiting the program 'turn off all the relay 'switches at both ports A and B BIOP.BAS DEFINT A-Z STARTUP AND INITIALIZATION MODULE This module introduces the user to the mechanics of the program, initializes some parameters, and declares global parameters. '$INCLUDE: 'GLOBAL.BI' CLS CALL INFORM 'Display the information for the program mechanics. CALL FILENAME(FToutS, RTout$, Commout$, FTnum, RTnum, Commnum)'Set disk Files Runprompt: LOCATE 23, 15: INPUT "Do you want to run the program? (Y/N) RAns$ = UCASE$(RAns$) RAns$ IF RAns$ = "Y" THEN GOTO Setscreen ELSEIF RAns$ = "N" THEN GOTO Theend ELSE GOTO Runprompt END IF Setscreen: CLS LOCATE 10, LOCATE 11, LOCATE 12, Initialize: 14: PRINT "The reactors are not in an anoxic mode." 14: PRINT "Anoxic Sequence Starting Times are the" 14: PRINT "following ... 1:10 am, 9:10 am and 5:10 pm. FOR x = 1 TO 5000 FOR y = 1 TO 100: NEXT X Checktimefi = TIMER NEXT y 'Delay to slow down the timer loop SCAN = 0 Scantime = SCAN.TIME Startup = 0 Flagloop = TRUE Flagdiff = TRUE Nitrate - FALSE Renew = FALSE Flagscrn = FALSE 'Poll the timer function 'Set the Scan counter to zero to start the scans. 'The Scan time is currently every 2 seconds. 'Used to control the Scanning Loop 'Flag for breaking out of and into Scanning Loop. 'Flag to signify no preceeding point in Diff Sub. 'No Nitrate Breakpoint Detected as of yet. 'Flag used to clear/reset Breakpt Sub variables. 'Flag indicating whether graphics is invoked VFAPass = 0 VFAPump = FALSE Acetate = FALSE Pt = 1 Startpt = l Endpt =180 'The VFA counter to time the pump operation. 'The RT Acetate Pump is off 'Acetate not added to the RT reactor yet 'Assign initial point of the start of graph. 'Storage of initial Pt value. 'There are 180 points in a Six Hour Graph. IF ChecktimeS > 0 THEN AnoxStartS = 4200 'Time: 1:10 am Datecheck = VAL(MID$(DATE$, 4, 2)) 'Perform Date check on the Data IF Datecheck <> FTnum THEN 'If past midnight (ie. new day) CALL FILENAME(FTout$, RTout$, Commout$, FTnum, RTnum, Commnum) 'file END IF IF ChecktimeS > 4200 THEN AnoxStartS = 33000 ' Time: 9:10 am IF ChecktimeS > 33000 THEN AnoxStartS = 61800 ' Time: 5:10 pm IF ChecktimeS > 61800 THEN GOTO Initialize SamplingTime: PolltimeS = TIMER 'Poll the timer function IF PolltimeS > AnoxStartS THEN 'The anoxic cycle commences GOTO StartRecording 'Start Recording the ORP values ELSE GOTO SamplingTime 'Return and poll the timer function again END IF StartRecording: OUT baseaddr%, SH0 FOR x = 1 TO 100: NEXT X i = INP(baseaddr% + 1) i = INP(baseaddr% + 1) CALL INITRELAYS 'Initialize the DT2814 A/D Board 'as per the DT2814 manual on pg. 5-9 / 'Initialize the relay board - set all relays off. OPEN Commout$ FOR APPEND AS #Commnum PRINT #Commnum, "Anoxic Period Started at StartAnoxS = PolltimeS Oper$ = "Acetate not added yet" TIME$ 'Write to the 'comment file CLS CALL LAYOUT CALL AXES 'Layout the text information. 'Calculate the relevant time axis. SCAN AND PLOTTING MODULE This module scans the ORP probes every 2 seconds and then every 2 minutes an average for each probe is calculated and plotted if graphics is invoked else an update is written to the screen in text mode. Scanning: ON TIMER(Scantime) GOSUB Readprobe 'Every 2 sec. go to the Readprobe Module TIMER ON 'Enable On Timer event-handling trapping routine DO 'Loop enclosing the entire program - to exit press <Escape> IF Flagloop = FALSE THEN 'Break out of the Scanning Loop TIMER STOP CALL DIFF(Flagdiff, Pt) 'Calculate the First Difference Flagdiff = FALSE 'Now Preceeding Pts are available CALL WRITING(Pt, FTout$, RTout$, FTnum, RTnum) 'Write data to disk IF Flagscrn = FALSE THEN CALL UPDATE(Pt) LOCATE 14, 46: PRINT Oper$ END IF IF Flagscrn = TRUE THEN CALL TRANSFER(ProbeID$, Pt) CALL PLOT(Pt) END IF 'Update the information screen 'Transfer the array of points 'Plot history of points to present INTERACTIVE MODULE This module allows the user to interact with the process allowing him to select any of the probes which he desires to observe on a real-time basis. kcode = jinkey% IF kcode THEN SELECT CASE kcode CASE KY.ESC EXIT DO CASE KY.LY GOTO Whichprobe Whichprobe: 'Test for Keystroke in the Keyboard buffer. 'Determine what the keystroke is. 'Exit from the program 'Which probe has been selected. LOCATE 23, 48: INPUT "Which Probe? (Letter)1*; Probe$ Probe$ = UCASES(Probe$) IF Probe$ = "A" OR Probe$ = "B" OR Probe$ = "C" THEN GOTO Startplot IF Probe$ = "D" OR Probe$ = "E" OR ProbeS = "F" THEN GOTO Startplot ELSE GOTO Whichprobe END IF Startplot: SCREEN 3 Flagscrn = TRUE CALL REFRESH(Probe$) ProbeID$ = TYPROBE$(Probe$) CALL TRANSFER(ProbelDS, Pt) CALL PLOT(Pt) LOCATE 23, 27: PRINT "Scan Number - " CASE KY.LN SCREEN 0 Flagscrn = FALSE 'For Hercules Graphics capabilities 'Do not overlay text mode on graphics 'Refresh the screen 'Identify the Selected probe 'Transfer the array of points 'Plot history of points to present CALL LAYOUT LOCATE 14, 46: PRINT Oper$ CALL UPDATE(Pt) CASE ELSE END SELECT END IF 'Turn off Hercules Graphics 'Invoke Text mode again 'Layout the text information 'Update the screen information 'Do nothing 'Closes Select Case kcode Structure. 'Closes IF kcode Decision Block. VFA ADDITION TO REAL-TIME REACTOR MODULE IF Acetate = FALSE THEN 'Acetate not added as of yet VFAddtimeS = TIMER 'Poll the TIMER Function IF VFAPump = FALSE THEN 'The pump is not currently on 'If nitrate knee was not detected - Acetate added after 2 hr 42 minutes '(ie. 6 minutes (3 passes) plus 2 minutes spare) prior to commencement 'of aeration period IF (VFAddtimeS - StartAnoxS) >= 9720 THEN 'Time is > than 2 hr 42 min. Relaynum% = 0 CALL RELAYSWITCH(Relaynum%) 'Acetate added to RT Reactor VFAPump = TRUE 'VFA RT pump is on PRINT #Commnum, "No Nitrate knee detected on "; DATES PRINT #Commnum, "Acetate pumped to RT reactor starting at "; TIME$ Oper$ = "Acetate RT Feed Pump On" IF Flagscrn = FALSE THEN LOCATE 14, 46: PRINT Oper$ Renew = TRUE 'Clear/Reset Breakpoint Sub CALL BREAKPT(Commnum, Pt, Nitrate, Renew) Renew = FALSE ELSE 'Search for nitrate breakpoint CALL BREAKPT(Commnum, Pt, Nitrate, Renew) IF Nitrate = TRUE THEN Relaynum% = 0 CALL RELAYSWITCH(Relaynum%) 'Acetate added to RT Reactor VFAPump = TRUE 'VFA RT pump is on PRINT #Commnum, "Nitrate knee detected at "; TIME$ PRINT #Commnum, "Acetate started to RT reactor at "; TIME$ OperS = "Acetate RT Feed Pump On" IF Flagscrn = FALSE THEN LOCATE 14, 46: PRINT Oper$ Renew = TRUE 'Clear/Reset the Breakpt Sub CALL BREAKPT(Commnum, Pt, Nitrate, Renew) Renew = FALSE END IF 'Closes IF Nitrate = TRUE Decision Block END IF 'Closes Real Time Acetate Addition Decision Block ELSE 'Since RT Acetate Pump is on VFAPass = VFAPass + 1 'Increment Pass Counter by 1 IF VFAPass > 2 THEN '6 min (3 passes) have elapsed Relaynum% = 0 CALL RELAYSWlTCH(Relaynum%) 'Turn off RT Acetate pump VFAPump = FALSE 'Reset Pump Variable VFAPass = 0 'Reset Pass Counter Acetate = TRUE 'Reset Acetate Variable PRINT #Commnum, "Acetate finished to RT reactor at "; TIME$ Oper$ = "RT Acetate has finished pumping" IF Flagscrn = FALSE THEN LOCATE 14, 46: PRINT OperS END IF END IF 'Closes IF VFAPump = FALSE Decision Block END IF 'Closes IF Acetate = FALSE Decision Block / Closure Statements TIMER ON 'Enable the On Timer trapping event-handling subroutine. Flagloop = TRUE 'Break back into the Scanning Loop. Pt = Pt + 1 'Increment point. END IF 'Closes IF Flagloop = FALSE Block Scanning Loop IF Pt = 181 THEN Startup = 3 'Breakout of the Loop LOOP WHILE Startup < 2 'Closes DO LOOP Structure. Theend: TIMER OFF CLOSE fCommnum 'Close the Comment File ONOFFmapfi = &HFFFF 'When exiting the program OUT (ioaddr%), ONOFFmapS 'turn off all the relay OUT (ioaddr% + 1 ) , ONOFFmapfi 'switches at both ports A and B CLS IF Startup = 3 THEN GOTO Setscreen END / " — • • ; : : ; : • •urrrrssTs^ssss-ssTKTnx-s • =—~-~—=—* ; J g a - — • • , , . . , ' READPROBE MODULE 'This module does the actual reading of the probes by calling the SCAN Sub Readprobe: SCAN = SCAN + 1 'Increment the SCAN Counter LOCATE 23, 42: PRINT USING '»###"; SCAN segmentt = VARSEG(MVolts(0, SCAN)) 'Produce the requisite FAR offset% = VARPTR(MVolts(0, SCAN)) 'Pointer to the data array 'Call the function returning an error code errnum% = getscanl%(baseaddr%, chanO%, chanl5%, segment%, offset%) IF errnum% <> 0 THEN PRINT #Commnum, "Getscan returned an error code at "; TIMES GOTO Theend END IF CALL SCANS (SCAN, Pt) 'Call the SCAN Subroutine IF SCAN = NUM. SCANS THEN '60 Scans (2 min) elapsed SCAN = 0 Flagloop = FALSE 'Break out of scanning loop END IF RETURN i INFORM.BAS 'SINCLUDE: 'GLOBAL.BI' 'Note: This is for the AASD#1 Program 242 THIS SUBROUTINE DETAILS THE MECHANICS OF THE PROGRAM SUB INFORM STATIC LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE 2, 3, 5, 6, 7, 8, 9, 10, 11, 12, 13, 15, 16, 17, END SUB 23: 23: 20: 15: 15: 15: 15: 20: 15: 15: 15: 27: 27: 27: PRINT PRINT PRINT PRINT PRINT PRINT PRINT : PRINT : PRINT PRINT PRINT PRINT PRINT PRINT "COMPUTER CONTROLLED SLUDGE DIGESTION " "USING OXIDATION-REDUCTION POTENTIAL" "This program allows the user to select and watch" "each of the individual ORP probes associated with " "both the Fixed-Time (#1) (3 hr air on / 3 hr air off) " "and the Real-Time (#2) (3 hr air on / variable time air" " off - depending upon nitrate breakpoint) Reactors. " "Each probe has been assigned a capital letter and " "for distinguishing purposes the ORP probes have been " "given the appendages a, b, and c to denote the front," "side and back probes respectively" "ORPla - A 0RP2a - D " "ORPlb - B 0RP2b - E " "ORPlC - C 0RP2C - F " ' INFORM.BAS '$INCLUDE: 'GLOBAL.BI' 'Note: This is for the AASD#2 Program THIS SUBROUTINE DETAILS THE MECHANICS OF THE PROGRAM SUB INFORM STATIC LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE 2, 3, 5, 6, 7, 8, 9, 10, 11, 12, 13, 15, 16, 17, END SUB 23: 23: 20: 15: 15: 15: 15: , 20: , 15: , 15: 15: 27: 27: 27: PRINT PRINT PRINT PRINT PRINT PRINT PRINT : PRINT ; PRINT : PRINT : PRINT : PRINT PRINT PRINT "COMPUTER CONTROLLED SLUDGE DIGESTION " "USING OXIDATION-REDUCTION POTENTIAL" "This program allows the user to select and watch" "each of the individual ORP probes associated with " "both the Fixed- (#1) (3 hr air on / 3 hr air off) and ' "Real-Time (#2) (50/50 variable times of air on and" " off, depending upon the nitrate breakpoint) Reactors. "Each probe has been assigned a capital letter and " "for distinguishing purposes the ORP probes have been ' "given the appendages a, b, and c to denote the front,1 "side and back probes respectively" "ORPla - A 0RP2a - D " "ORPlb - B ORP2b - E " "ORPlC - C ORP2C - F " i INFORM.BAS '$INCLUDE: •GLOBAL.BI• 'Note: This is for the BIO-P Program THIS SUBROUTINE DETAILS THE MECHANICS OF THE PROGRAM SUB INFORM STATIC LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 13, 14, 15, 16, 17, 19, 20, 21, 22: 22: 27: 16: 14: 14: 14: 14: 14: 14: 16: 14: 14: 14: 14: 27: 27: 27: PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT "EXCESS BIOLOGICAL PHOSPHORUS REMOVAL USING" "OXIDATION REDUCTION POTENTIAL DETECTION OF" "THE DISSAPPEARANCE OF NITRATES" "This program demonstrates the use of ORP as a control" "parameter for bio-p processes in a sequencing batch " "reactor. Sodium Acetate is added to the Fixed Time " "Reactor (nr. rt.) at a preset time during the anoxic" "sequence, while the addition of VFAs to the Real Time" "Reactor (far.rt,) is governed by the detection of the" "ORP breakpt. corresponding to nitrate dissappearance." "The user can select and watch any probe in the " "FT (#1) or RT(#2) reactors where each probe has been" "assigned a capitol letter and for distinguishing" "purposes an appendage a, b, or c to denote the front," "side and back probes respectively" "ORPla - A ORP2a - D" "ORPlb - B ORP2b - E" "ORPlc - C 0RP2c - F" END SUB FILENAME.BAS '$INCLUDE: 'GLOBAL.BI' •Note: This is for ALL Programs • A SUBROUTINE WHICH GENERATES THE FILENAMES FOR THE DATA FILES • — — i • .., , . — — — — — — SUB FILENAME (FToutS, RTout$, CommoutS, FTnum, RTnmn, Commnum) Temp$ = DATE$ YearS = RIGHT$(Temp$, 2) Month$ = LEFTS(Temp$, 2) Day$ = MIDS(Temp$, 4, 2) Composite$ = Year$ + "-" + Months + "-" + Day$ FTout$ =• CompositeS + ».FT«I RToutS = CompositeS + ".RT" CommoutS = CompositeS + ".msg FTnum = VAL(DayS) RTnum = FTnum + 100 Commnum =» FTnum + 200 OPEN FTOUtS FOR APPEND AS #FTnum PRINT #FTnum, " TIME Seconds PRINT #FTnum, " DOxl DORPla PRINT #FTnum, •", CLOSE #FTnum 'Fixed Time Filename 'Real Time Filename 'The Comments Filename" 'Arbitrary numbering system 'Arbitrary numbering system 'Arbitrary numbering system •Print out file headings ORPla ORPlb ORPlc DORPlb DORPlc" OPEN RTOUtS FOR APPEND AS #RTnum PRINT #RTnum, " TIME Seconds PRINT #RTnum, " DOX2 DORP2a PRINT #RTnum, "" CLOSE #RTnum 'Print out file headings ORP2a ORP2b ORP2C DORP2b DORP2C" END SUB 'SINCLUDE: 'GLOBAL.BI' 'Note: This is for ALL Programs REFRESH.BAS THIS SUBROUTINE REFRESHES THE SCREEN FOR THE NEXT PROBE'S PLOTS SUB REFRESH (ProbeS) STATIC CALL ORPSCRN ProbelDS - TYPROBE$(Probe$) LOCATE 23, 2: PRINT "Showing Probe - "; LOCATE 23, 48: PRINT "Select Another ? ProbelDS (Y/N)"' 'Refresh the Screen with 'ORP Graph cooridinates END SUB 244 INITREL.BAS $INCLUDE: 'GLOBAL.BI' Note: This is for ALL Programs A SUBROUTINE WHICH INITIALIZES THE SOLID STATE RELAY CONTROL 10 BOARD This subroutine is designed to output 16 bits of data to control the solid state relays that are connected to Metrabyte's PIO-12 I/O Board for the the IBM PC. Port A Relays: 0 - 7 Relay Control Bits: 1 = OFF Port B Relays: 8 - 1 5 0 = ON Note: In setting up the port configuration it initializes all relays of ports A and B to OFF. To do this it leaves the global variable ONOFFmapS = SHFFFF with all 32 bits set to 1. The global constant ioaddr% is also used. SUB INITRELAYS STATIC OUT (ioaddrt + 3 ) , &H80 ONOFFmapS = SHFFFF OUT (ioaddr%), ONOFFmapS OUT (ioaddr% + 1), ONOFFmapS END SUB 'Sets up all ports (A,B,C) as output 'ports. Note: OUT (ioaddr% + 3 ) , SH89 'would be used for inputs to port C 'Set global variables for all relays off 'Set all port A relays off 'Set all port B relays off '$INCLUDE: 'GLO BAL.BI• 'Note: This is for ALL Programs RELAY.BAS ' A SUBROUTINE WHICH FLIPS THE BIT TO CHANGE THE RELAY SWITCH STATUS * Note: The subroutine scans the global variable ONOFFmapS which indicates ' the present relay status and uses it to turn Relaynum% ON if OFF, or ' OFF if ON. Again the Relay control bits are 1 = OFF and 0 = ON. • SUB RELAYSWITCH (Relaynum%) SmaskS = 0 RmaskS = ONOFFmapS SmaskS = SmaskS OR (2 Relaynum%) IF (ONOFFmapS AND SmaskS) <> 0 THEN SmaskS = SmaskS XOR SHFFFF Rmasks = Rmasks AND SmaskS ELSE Rmasks = Rmasks OR SmaskS END IF 'Update the global relay status variable IF RmaskS = -65535 THEN RmaskS = 0 IF RmaskS = 65535 THEN RmaskS = SHFFFF ONOFFmapS = Rmasks •Get the present relay status •Set relay bit Relaynum% = 1 'Relay Relaynum% is OFF 'Flip the lower 16 bits 'Transfer the ON bit into the 'Present Relay Status Word 'Relay Relaynum% is ON 'Transfer the OFF bit into the 'Present Relay status Word 'Output the Updated relay status word to I/O ports A and B 'The lower byte to Port A OUT (ioaddr%), RmaskS Bmask% = RmaskS IF Bmask% < 0 THEN Bmask% = Bmask% XOR SHFFFF Bmask% = (Bmask% \ SH100) Bmask% = Bmask% XOR SHFFFF ELSE Bmask% = (Bmask% \ SH100) END IF •Flip the bits •Shift Hi-byte Pattern into the Low-byte 'Flip the bits back again OUT (ioaddr% + 1), Bmask% 'The higher byte to port B END SUB 245 '$INCLUDE: 'GLOBAL.BI' •Note: This is for ALL Programs AXES.BAS A SUBROUTINE WHICH CALCULATES THE RELEVANT TIME SCALE AXIS SUB AXES STATIC Seconds* = TIMER HourO = Seconds* \ 3600 DigitOl = HourO \ 10 Hourrem! = Seconds* / 3600 Digitreml! =• HourO / 10 Digit02 = ((Digitreml! - DigitOl) * 10) Mintrunc! = (Hourrem! - HourO) * 60 Digit3 = Mintrunc! \ 10 Digitrem2! = Mintrunc! / 10 Digit4 = ((Digitrem2! - Digit3) * 10) \ 1 Hour2 = HourO Hour4 = HourO Hour6 = HourO + 2 + 4 + 6 IF Hour2 > 24 THEN Hour2 = Hour2 - IF Hour4 > 24 THEN Hour4 = Hour4 - IF Hour6 > 24 THEN Hour6 = Hour6 - Digit21 = Hour2 \ 10 Digit41 = Hour4 \ 10 Digitei = Hour6 \ 10 Digit22 = ((Hour2 / 10) - Digit21) Digit42 = ((Hour4 / 10) - Digit41) Digit62 = ((Hour6 / 10) - Digitei) END SUB 24 24 24 * 10 * 10 * 10 'Calculate the first two •digits of the starting time. 'First digit 0 hour •Second digit 0 hour 'Calc. third & fourth digits 'Third digit 0, 2, 4, 6 hours •Fourth digit 0, 2, 4, 6 hours •Check if time scale extends 'into the next day. 'First digit 2 hour 'First digit 4 hour 'First digit 6 hour 'Second digit 2 hour 'Second digit 4 hour 'Second digit 6 hour '$INCLUDE: 'GLOBAL.BI' 'Note: This is for ALL Programs PAXIS.BAS A SUBROUTINE WHICH PRINTS OUT THE RELEVANT TIME SCALE AXIS SUB PAXIS STATIC LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE 21, 17: 21, 19: 21, 20: 21, 31: 21, 33: 21, 34: 21, 44: 21, 46: 21, 47: 21, 58: 21, 60: 21, 61: PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT USING "#"; i t . ti USING "#"; USING "#"; n . n USING "#"; USING "#"; it. n USING "#"; USING "I"; n • n USING "#"; DigitOl; Digit02 Digit3; Digit21; Digit3; Digit41; Digit3; Digit61 Digit4 r Digit22 Digit4 : Digit42 Digit4 ; Digit62 Digit3; Digit4 END SUB '$INCLUDE: 'GLOBAL.BI' 'Note: This is for all Programs SCANS.BAS THIS SUBROUTINE SUMS AND AVERAGES THE PROBE READINGS SUB SCANS (SCAN, Pt) STATIC 'Sum the Scans MVoltslaS MVoltslbS MVoltslcS MVolts2aS MVolts2b& MVolts2cS MVoltDOlS MVoltD02S = = = = = = = = MVoltslaS MVoltslbS MVoltslcS MVolts2aS MVolts2bS MVolts2cS MVoltDOlS MVoltD02S + + + + + + + + MVolts(0, MVolts(1, MVolts(2, MVolts(3, MVolts(4, MVolts(5, MVolts(6, MVolts(7, SCAN) SCAN) SCAN) SCAN) SCAN) SCAN) SCAN) SCAN) IF SCAN = NUM.SCANS THEN •60 Scans therefore calculate 2 minute avg. reading for each probe ORPla(Pt) ORPlb(Pt) ORPlc(Pt) 0RP2a(Pt) 0RP2b(Pt) 0RP2c(Pt) DOxl(Pt) = D0x2(Pt) = = MVoltslaS / SCAN = MVoltslbS / SCAN = MVoltslcS / SCAN = MVolts2aS / SCAN = MVolts2bS / SCAN = MVolts2cS / SCAN MVoltDOlS / SCAN MVoltD02S / SCAN •Convert digital numbers to millivoltages ORPla(Pt) ORPlb(Pt) ORPlc(Pt) 0RP2a(Pt) 0RP2b(Pt) ORP2c(Pt) DOXl(Pt) > DOx2(Pt) = DOxl(Pt) = DOx2(Pt) > = ((ORPla(Pt) = ((ORPlb(Pt) = ((ORPlc(Pt) • ((ORP2a(Pt) = ((0RP2b(Pt) = ((ORP2c(Pt) ((DOxl(Pt) - ((DOx2(Pt) - .082317 * " .082317 * - 2048) - 2048) - 2048) - 2048) - 2048) - 2048) 2048) / 2048) / (DOxl(Pt)) (DOx2(Pt)) / 2048) / 2048) / 2048) / 2048) / 2048) / 2048) 2048) * 2048) * + .251 + .251 'Reset the millivoltage sum to zero MVoltslaS = 0: MVoltslbS = 0: MVoltslcS MVolts2aS = 0: MVolts2bS = 0: MVolts2cS MVoltDOlS = 0: MVoltD02& = 0: 500 500 500 500 500 500 500 500 END IF END SUB 247 i DIFF.BAS '$INCLUDE: 'GLOBAL.BI' •Note: This is for AASD#1 and AASD#2 Programs A SUBROUTINE WHICH CALCULATES THE FIRST DIFFERENCE OF THE ORP PROFILES SUB DIFF (Flagdiff, Pt) Precpt = Pt - 1 IF Flagdiff = TRUE THEN ORPla(Precpt) = ORPla(Pt) ORPlb(Precpt) - ORPlb(Pt) ORPlc(Precpt) = ORPlc(Pt) ORP2a(Precpt) = ORP2a(Pt) ORP2b(Precpt) = ORP2b(Pt) ORP2c(Precpt) = ORP2c(Pt) END IF IF Flagdiff = FALSE AND Pt = Startpt THEN •At start up of program the initial 'first difference point will be set 'equal to zero since there is no •preceeding point. END IF ORPla(Precpt) ORPlb(Precpt) ORPlc(Precpt) 0RP2a(Precpt) 0RP2b(Precpt) 0RP2c(Precpt) ORPla(Endpt) ORPlb(Endpt) ORPlc(EndDt) 0RP2a(Endpt) 0RP2b(Endpt) ORP2c(Endpt) 'Store last point so it becomes •first point of the next cycle. •Calculate the First Difference of the ORP (2 minute intervals) DORPla(Pt) DORPlb(Pt) DORPlc(Pt) DORP2a(Pt) DORP2b(Pt) DORP2c(Pt) (ORPla(Pt) (ORPlb(Pt) (ORPlc(Pt) (ORP2a(Pt) (ORP2b(Pt) (ORP2c(Pt) ORPla(Precpt)) / 2 ORPlb(Precpt)) / 2 ORPlc(Precpt)) / 2 ORP2a(Precpt)) / 2 0RP2b(Precpt)) / 2 ORP2c(Precpt)) / 2 END SUB i DIFF.BAS '$INCLUDE: 'GLOBAL.BI' 'Note: This is for the BIO-P Program A SUBROUTINE WHICH CALCULATES THE FIRST DIFFERENCE OF THE ORP PROFILES SUB DIFF (Flagdiff, Pt) Precpt = Pt - 1 IF Flagdiff = TRUE THEN ORPla(Precpt) = ORPla(Pt) ORPlb(Precpt) = ORPlb(Pt) ORPlc(Precpt) = ORPlc(Pt) ORP2a(Precpt) = ORP2a(Pt) ORP2b(Precpt) = ORP2b(Pt) ORP2c(Precpt) = ORP2c(Pt) END IF 'At start up of program the initial 'first difference point will be set 'equal to zero since there is no 'preceeding point. 'Calculate the First Difference of the ORP (2 minute intervals) DORPla(Pt) DORPlb(Pt) DORPlc(Pt) DORP2a(Pt) DORP2b(Pt) DORP2c(Pt) (ORPla(Pt) (ORPlb(Pt) (ORPlc(Pt) (ORP2a(Pt) (ORP2b(Pt) (ORP2c(Pt) ORPla(Precpt)) / 2 ORPlb(Precpt)) / 2 ORPlc(Precpt)) / 2 ORP2a(Precpt)) / 2 0RP2b(Precpt)) / 2 ORP2c(Precpt)) / 2 END SUB •$INCLUDE: 'GLOBAL.BI• 'Note: This is for ALL Programs ORPSCRN.BAS A SUBROUTINE WHICH SETS UP THE ORP GRAPHING CO-ORDINATES SUB ORPSCRN STATIC CLS 'Set up the Initial Boxes and Graph Dimensions LINE (0, 0)-(719, 335), , B LINE (110, 10)-(590, 270), , B LINE (110, 160)-(590, 160) •Put in the tick marks for the Time scale axis Pixtime = 110 FOR i = 1 TO 9 PSET (Pixtime, 271) PSET (Pixtime, 272) Pixtime = Pixtime + 60 NEXT i 'Put in the tick marks for the ORP scale axis Pixorp = 10 FOR j = 1 TO 11 PSET (109, Pixorp) PSET (108, Pixorp) Pixorp = Pixorp + 25 NEXT j 'Print out the Time Scale Axis CALL PAXIS LOCATE 22, 35: PRINT "Time (hrs)" 'Print out LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE END SUB the ORP Scale Axis 2, 9: PRINT "300" 5, 9: PRINT "200" 8, 9: PRINT "100" 12, 9: PRINT " 0" 16, 8: PRINT "-100" 19, 8: PRINT "-200" 6, 2: PRINT " O" 7, 2: PRINT " R" 8, 2: PRINT " P" 10, 2: PRINT " (mv)' • $INCLUDE: •GLOBAL.BI' 'Note: This is for ALL Programs WRITING.BAS • THIS SUBROUTINE WRITES THE DATA TO THE DISK FILE SUB WRITING (Pt, FTout$, RTout$, FTnum, RTnum) STATIC 'Write to the Fixed-Time Disk File OPEN FTout$ FOR APPEND AS FTnum PRINT #FTnum, TIME$; " "; PRINT #FTnum, USING "#####.## "; TIMER; PRINT #FTnum, USING "+###.## "; ORPla(Pt); ORPlb(Pt); ORPlc(Pt); PRINT #FTnum, USING " #.# "; DOxl(Pt); PRINT #FTnum, USING "+###.## "; DORPla(Pt); DORPlb(Pt); DORPlc(Pt) CLOSE #FTnum •Write to the Real-Time Disk file OPEN RTout$ FOR APPEND AS RTnum PRINT #RTnum, TIME$; " "; PRINT #RTnum, USING "#####.## "; TIMER; PRINT #RTnum, USING "+###.## "; ORP2a(Pt); ORP2b(Pt); 0RP2c(Pt); PRINT #RTnum, USING " #.# "; DOx2(Pt); PRINT #RTnum, USING "+###.## "; D0RP2a(Pt); DORP2b(Pt); DORP2c(Pt) CLOSE #RTnum END SUB i TRANSFER.BAS '$INCLUDE: 'GLOBAL.BI• 'Note: This is for ALL Programs ' A SUBROUTINE WHICH TRANSFERS THE PROBE READINGS TO A GENERAL ARRAY ' READY FOR PLOTTING I I - — — — — — — — — — — — — — — — = = — = - =L=m LUlt as——-33;—=——= , ^ = — — _ — — — • — - SUB TRANSFER (ProbeID$, Pt) SELECT CASE ProbeID$ CASE "ORPla" FOR i = startpt TO Pt ORP(i) = ORPla(i) NEXT i CASE "ORPlb" FOR i = startpt TO Pt ORP(i) = ORPlb(i) NEXT i CASE "ORPlc" FOR i = startpt TO Pt ORP(i) = ORPlo(i) NEXT i CASE "ORP2a" FOR i = Startpt TO Pt ORP(i) = ORP2a(i) NEXT i CASE "ORP2b" FOR i = Startpt TO Pt ORP(i) = ORP2b(i) NEXT i CASE "ORP2C" FOR i = Startpt TO Pt ORP(i) = ORP2c(i) NEXT i END SELECT END SUB i PLOT.BAS '$INCLUDE: •GLOBAL.BI• 'Note: This is for ALL Programs ' A SUBROUTINE WHICH PLOTS THE PROBE READINGS UP TO THE PRESENT POINT SUB PLOT (Pt) FOR j = Startpt TO Pt 'Proportion to transform ORP values to pixels Markl = (ORP(j) / 50) * 25 Pixel1 - 160 - Markl 'Plot the point PSET (168 + 2 * j, Pixell) NEXT j END SUB . LAYOUT.BAS — •$INCLUDE: 'GLOBAL.BI• 'Note: This is for AASD#1 and AASD#2 Programs THIS SUBROUTINE LAYS OUT THE TEXT INFORMATION SCREEN SUB LAYOUT STATIC CLS LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE END SUB 2, 23: PRINT "COMPUTER CONTROLLED SLUDGE DIGESTION " 3, 23: PRINT "USING OXIDATION-REDUCTION POTENTIAL " 5, 13: PRINT "RCTR #1 - FIXED TIME" 5, 46: PRINT "RCTR #2 - REAL TIME" 7, 13: PRINT "ORPla - " 7, 46: PRINT "ORP2a - " 9, 13: PRINT "ORPlb - " 9, 46: PRINT "ORP2b - " 11, 13: PRINT "ORPlc - " 11, 46: PRINT "ORP2C - " 13, 13: PRINT "Time of Last Update - " 13, 46: PRINT "Point Number - " 15, 13: PRINT "Note: Hit <Y> - Yes - if desire to see ORP plots" 16, 23: PRINT "<N> - No - when finished viewing plots" 17, 23: PRINT "<ESC> - Escape - to exit program" 19, 13: PRINT "Note: Time is updated every two minutes" 20, 19: PRINT "There are 60 scans (at 2 sec intervals) in 2 min" 21, 19: PRINT "There are 180 pts ( 2 min intervals) in a 6 hr cycle" 23, 30: PRINT "Scan number - " • LAYOUT.BAS '$INCLUDE: 'GLOBAL.BI' •Note: This is for the BIO-P Program THIS SUBROUTINE LAYS OUT THE TEXT INFORMATION SCREEN SUB LAYOUT STATIC CLS LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE LOCATE 2, 3, 5, 5, 7, 7, 9, 9, 11, 11, 13, 13, 14, 16, 17, 18, 19, 20, 21, 23, 15: 17: 13: 46: 13: 46: 13: 46: 13: 46: 13: 46: 13: 13: 23: 23: 13: 19: 19: 30: PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT PRINT "COMPUTER CONTROLLED ADDITION OF A VFA CARBON SOURCE" "BASED ON THE ORP-TIME VARIATION IN A BIO-P PROCESS " "RCTR #1 - FIXED TIME" "RCTR #2 - REAL TIME" "ORPla - " "ORP2a - " "ORPlb - " "ORP2b - " "ORPlc - " "ORP2C - " "Time of Last Update - " "Point Number - " "Acetate Addition Status Report - " "Note: Hit <Y> - Yes - if desire to see ORP plots" "<N> - No - when finished viewing plots" "<ESC> - Escape - to exit program" "Note: Time is updated every two minutes" "There are 60 scans (at 2 sec intervals) in 2 min" "There are 180 pts ( 2 min intervals) in a 6 hr cycle" "Scan number - " END SUB i UPDATE.BAS '$INCLUDE: 'GLOBAL.BI' 'Note: This is for ALL Programs ' THIS SUBROUTINE UPDATES THE SCREEN LAYOUT EVERY TWO MINUTES I _ — _ — — — — . m ^ ^ . _ - = = = = a = = = = = = = = = m ; SUB UPDATE (Pt) STATIC LOCATE 7, 25: PRINT USING "+###.#"; ORPla(Pt) LOCATE 7, 57: PRINT USING "+###.#"; ORP2a(Pt) LOCATE 9, 25: PRINT USING "+###.#"; ORPlb(Pt) LOCATE 9, 57: PRINT USING "+###.#"; ORP2b(Pt) LOCATE 11, 25: PRINT USING "+###.#"; ORPlc(Pt) LOCATE 11, 57: PRINT USING "+###.#"; ORP2c(Pt) LOCATE 13, 35: PRINT TIME$ LOCATE 13, 62: PRINT USING "###"; Pt END SUB • TYPROBE.BAS '$INCLUDE: * GLOBAL.BI' 'Note: This is for ALL Programs A FUNCTION WHICH IDENTIFIES THE SELECTED PROBE FUNCTION TYPROBE$ (Probe$) STATIC SELECT CASE Probe$ CASE CASE CASE CASE CASE CASE CASE CASE CASE "A" TYPROBE$ »B" TYPROBE$ n^n TYPROBE$ IIQlt TYPROBES "E" TYPROBE$ u p ii TYPROBES " G" TYPROBE$ "H" TYPROBES ELSE TYPROBES a> = = = = ss Si = = "ORPla" "ORPlb" "ORPlc" "ORP2a" "ORP2b" "ORP2C" "D.O.#l" "D.O.#2" "No such probe" END SELECT END FUNCTION JINKEY FUNCTION 'This function tests for a key stroke in the keyboard buffer. FUNCTION jinkey% a$ = INKEYS IF a$ = "" THEN jinkey% = 0: EXIT FUNCTION 'Nothing there - exit IF LEN(a$) = 2 THEN 'Something there - obtain jinkey% = ASC(MID$(a$, 2, 1)) + &H100 'ASCII Code ELSE jinkey% = ASC(a$) END IF END FUNCTION > BREAKPT.BAS - '$INCLUDE: 'GLOBAL.BI' 'Note: This is for AASD#1 and AASD#2 Programs ' THIS SUBROUTINE FINDS THE NITRATE BREAKPOINT (KNEE) SUB BREAKPT (Commnum, Pt, Nitrate, Renew) STATIC IF Renew = FALSE THEN 'Drop through Subroutine instead of resetting Avoid = Avoid + 1 'Increment ORP stability counter after feeding IF Avoid > MAXAVOID THEN 'ORP should have stabilized by now Count = Count + 1 'Increment internal Ring counter IF Pt <= RINGSIZE THEN 'In Subsequent cycles the Ring LowBound = Pt + 180 - RINGSIZE 'Buffer may straddle two cycles ELSE LowBound = Pt - RINGSIZE END IF IF Count <= RINGSIZE THEN 'Ring is not full SumA! «• SumA! + DORP2a(Pt) 'Sum the First Difference values SumB! = SumB! + DORP2b(Pt) SumC! = SumC! + DORP2c(Pt) IF Count = RINGSIZE THEN 'The Ring is full Ringnum = 1 'Assign Ring Number RING2a(Ringnum) = SumA! / RINGSIZE 'Calculate the average RING2b(Ringnum) = SumB! / RINGSIZE 'Slope for the Ring RING2c(Ringnum) = SumC! / RINGSIZE FirstRingA! = RING2a(Ringnum) 'This becomes the first FirstRingB! = RING2b(Ringnum) 'Ring of the Ring Buffer FirstRingC! = RING2c(Ringnum) END IF ELSEIF Count > RINGSIZE AND Search = FALSE THEN 'Start filling next ring Ringnum = Ringnum + 1 'Increment Ring Number SumA! = SumA! - DORP2a(LowBound) + DORP2a(Pt) 'Kick out First SumB! = SumB! - DORP2b(LowBound) + DORP2b(Pt) 'value and add in SumC! = SumC! - DORP2C(LowBound) + DORP2c(Pt) 'latest First Diff RING2a(Ringnum) = SumA! / RINGSIZE 'Calculate avg RING2b(Ringnum) = SumB! / RINGSIZE 'First Diff of RING2C(Ringnum) = SumC! / RINGSIZE 'this new Ring IF Ringnum = NUMRINGS THEN 'The Ring Buffer is Full Search = TRUE 'Enable Search for Breakpoint LastRingA! = RING2a(Ringnum) 'The most recently calculated LastRingB! = RING2b(Ringnum) 'Ring becomes the last Ring LastRingC! = RING2c(Ringnum) 'in the Buffer DiffRingA! = LastRingA! - FirstRingA! 'Take the Diff between DiffRingB! = LastRingB! - FirstRingB! 'the first and last DiffRingC! = LastRingC! - FirstRingC! 'Rings in the Buffer END IF END IF IF Search = TRUE THEN 'Search for the Nitrate Breakpoint IF KneeA = FALSE THEN 'Knee 0RP2a not detected as of yet IF DiffRingA! <= DELTA2A! THEN 'Arbitrary Constraint KneeA = TRUE KneeCount = KneeCount + 1 PRINT #Commnum, "Nitrate KneeA detected on "; DATES; PRINT Icommnum, " at approximately "; TIME$ END IF END IF IF KneeB = FALSE THEN 'Knee 0RP2b not detected as of yet IF DiffRingB! <= DELTA2B! THEN KneeB = TRUE KneeCount = KneeCount + 1 PRINT #Commnum, "Nitrate KneeB detected on "; DATES; PRINT #Commnum, " at approximately "; TIME$ END IF END IF IF KneeC = FALSE THEN 'Knee 0RP2C not detected as of yet IF DiffRingC! <= DELTA2CJ THEN KneeC = TRUE KneeCount = KneeCount + 1 PRINT #Commnum, "Nitrate KneeC detected on '•; DATES; PRINT #Commnum, " at approximately "; TIMES END IF END IF IF KneeCount >= 2 THEN Nitrate = TRUE '>= Two knees detected END IF 'Closes If Search = TRUE Decision Block ELSEIF Count > RINGSIZE AND Search = TRUE THEN 'Ring Buffer moves along Ringnum = Ringnum + l 'Increment Ring Number SumA! = SumAi - DORP2a(LowBound) + DORP2a(Pt) SumB! = SumB! - D0RP2b(LowBound) + DORP2b(Pt) SumC! = SumC! - D0RP2c(LowBound) + D0RP2c(Pt) RING2a(Ringnum) = SumAi / RINGSIZE RING2b(Ringnum) = SumB! / RINGSIZE RING2c(Ringnum) => SumC! / RINGSIZE FirstRingA! = RING2a(Ringnum - RINGSIZE + 1) FirstRingB! = RING2b(Ringnum - RINGSIZE + 1) FirstRingC! = RING2C(Ringnum - RINGSIZE + 1) LastRingA! = RING2a(Ringnum) LastRingB! = RING2b(Ringnum) LastRingC! = RING2c(Ringnum) DiffRingA! = LastRingA! - FirstRingA! DiffRingB! = LastRingB! - FirstRingB! DiffRingC! = LastRingC! - FirstRingC! 'Kick out First 'value and add in 'latest First Diff 'Calculate the 'average slope 'for the Ring 'Assign the 'First Ring of 'the new Buffer 'The latest Ring 'becomes the last 'Ring of Buffer 'Calculate Diff 'between first 'and last Rings IF KneeA = FALSE THEN 'Knee 0RP2a not detected as of yet IF DiffRingA! <= DELTA2A! THEN KneeA = TRUE KneeCount = KneeCount + 1 PRINT #Commnum, "Nitrate KneeA detected on "; DATES; PRINT #Commnum, " at approximately "; TIMES END IF END IF IF KneeB = FALSE THEN 'Knee 0RP2b not detected as of yet IF DiffRingB! <= DELTA2B! THEN KneeB = TRUE KneeCount = KneeCount + 1 PRINT #Commnum, "Nitrate KneeB detected on "; DATE$; PRINT fCommnum, " at approximately "; TIME$ END IF END IF IF KneeC = FALSE THEN 'Knee ORP2c not detected as of yet IF DiffRingC! <= DELTA2C! THEN KneeC = TRUE KneeCount = KneeCount + 1 PRINT fCommnum, "Nitrate KneeC detected on "; DATE$; PRINT #Commnum, " at approximately "; TIME$ END IF END IF END IF END ELSE KneeA KneeB KneeC Avoid Count SumA! SumB! SumC! IF = FALSE => FALSE = FALSE = 0 = 0 = 0 = 0 = 0 Search = FALSE KneeCount = 0 END IF IF KneeCount >= 2 THEN Nitrate = TRUE '>= Two knees detected 'Closes If Count <= Ringsize Decision Block 'Closes If Avoid > MaxAvoid Decision Block 'Clear and Reset all the Variables for next Cycle 'Closes Renew = FALSE Decision Block END SUB / BREAKPT.BAS '$INCLUDE: 'GLOBAL.BI' 'Note: This is for the BIO-P Program ' THIS SUBROUTINE FINDS THE NITRATE BREAKPOINT (KNEE) SUB BREAKPT (Commnum, Pt, Nitrate, Renew) STATIC IF Renew = FALSE THEN 'Drop through Subroutine instead of resetting Avoid = Avoid + 1 'Increment ORP stability counter after feeding IF Avoid > HAXAVOID THEN Count = Count + l LowBound = Pt - RINGSIZE IF Count <= RINGSIZE THEN SumA! - SumA! + DORP2a(Pt) SumB! - SumB! + DORP2b(Pt) SumC! = SumC! + DORP2c(Pt) IF Count = RINGSIZE THEN Ringnum = 1 'ORP should have stabilized by now 'Increment internal Ring counter 'Calculate lower bound of the Ring 'Ring is not full 'Sum the First Difference values 'The Ring is full 'Assign Ring Number RING2a(Ringnum) = SumA! / RINGSIZE RING2b(Ringnum) = SumB! / RINGSIZE RING2C(Ringnum) = SumC! / RINGSIZE FirstRingA! = RING2a(Ringnum) FirstRingB! = RING2b(Ringnum) FirstRingC! = RING2C(Ringnum) 'Calculate the average 'Slope for the Ring 'This becomes the first 'Ring of the Ring Buffer END IF ELSEIF Count > RINGSIZE AND Search = FALSE THEN 'Start filling next ring Ringnum = Ringnum + 1 'Increment Ring Number SumA! = SumA! - D0RP2a(LowBound) + DORP2a(Pt) SumB! = SumB! - DORP2b(LowBound) + DORP2b(Pt) SumC! = SumC! - DORP2C(LowBound) + DORP2c(Pt) RING2a(Ringnum) = SumA! / RINGSIZE RING2b(Ringnum) = SumB! / RINGSIZE RING2c(Ringnum) = SumC! / RINGSIZE 'Kick out First 'value and. add in 'latest First Diff 'Calculate avg 'First Diff of 'this new Ring IF Ringnum = NUMRINGS THEN Search = TRUE LastRingA! = RING2a(Ringnum) LastRingB! = RING2b(Ringnum) LastRingC! = RING2c(Ringnum) 'The Ring Buffer is Full 'Enable Search for Breakpoint 'The most recently calculated 'Ring becomes the last Ring 'in the Buffer DiffRingA! = LastRingA! - FirstRingA! 'Take the Diff between DiffRingB! = LastRingB! - FirstRingB! 'the first and last DiffRingC! = LastRingC! - FirstRingC! 'Rings in the Buffer END IF 256 IF Search = TRUE THEN 'Search for the Nitrate Breakpoint IF KneeA = FALSE THEN 'Knee 0RP2a not detected as of yet IF DiffRingA! <= DELTA2A! THEN 'Arbitrary Constraint KneeA = TRUE KneeCount = KneeCount + 1 PRINT #Commnum, "Nitrate KneeA detected on "; DATES; PRINT ICommnum, " at approximately "; TIMES END IF END IF IF KneeB = FALSE THEN 'Knee 0RP2b not detected as of yet IF DiffRingB! <= DELTA2B! THEN KneeB = TRUE KneeCount = KneeCount + 1 PRINT ICommnum, "Nitrate KneeB detected on "; DATES; PRINT #Commnum, " at approximately "; TIMES END IF END IF IF KneeC = FALSE THEN 'Knee 0RP2c not detected as of yet IF DiffRingC! <= DELTA2C! THEN KneeC = TRUE KneeCount = KneeCount + l PRINT #Commnum, "Nitrate KneeC detected on "; DATES; PRINT #Commnum, " at approximately "; TIMES END IF END IF IF KneeCount >= 2 THEN Nitrate = TRUE '>= Two knees detected END IF 'Closes If Search = TRUE Decision Block ELSEIF Count > RINGSIZE AND Search = TRUE THEN 'Ring Buffer moves along Ringnum = Ringnum + 1 'Increment Ring Number SumAi = SumA! - DORP2a(LowBound) + DORP2a(Pt) 'Kick out First SumB! = SuraB! - DORP2b(LowBound) + D0RP2b(Pt) 'value and add in SumC! = SumC! - DORP2c(LowBound) + DORP2c(Pt) 'latest First Diff RING2a(Ringnum) = SumA! / RINGSIZE RING2b(Ringnum) = SumB! / RINGSIZE RING2C(Ringnum) = SumC! / RINGSIZE 'Calculate the 'average slope 'for the Ring FirstRingA! = RING2a(Ringnum - RINGSIZE + 1) 'Assign the FirstRingB! = RING2b(Ringnum - RINGSIZE + 1) 'First Ring of FirstRingC! = RING2c(Ringnum - RINGSIZE + 1) 'the new Buffer LastRingA! = RING2a(Ringnum) LastRingB! = RING2b(Ringnum) LastRingC! = RING2C(Ringnum) DiffRingA! DiffRingB! DiffRingC! LastRingA! - FirstRingA! LastRingB! - FirstRingB! LastRingC! - FirstRingC! 'The latest Ring 'becomes the last 'Ring of Buffer 'Calculate Diff 'between first 'and last Rings IF KneeA = FALSE THEN 'Knee 0RP2a not detected as of yet IF DiffRingA! <= DELTA2A! THEN KneeA = TRUE KneeCount = KneeCount + 1 PRINT #Commnum, "Nitrate KneeA detected on "; DATES; PRINT #Commnum, " at approximately "; TIMES END IF END IF IF KneeB = FALSE THEN 'Knee 0RP2b not detected as of yet IF DiffRingB! <= DELTA2B! THEN KneeB = TRUE KneeCount = KneeCount + 1 PRINT #Commnum, "Nitrate KneeB detected on "; DATES; PRINT #Commnum, " at approximately "; TIMES END IF END IF IF KneeC = FALSE THEN 'Knee 0RP2c not detected as of yet IF DiffRingC! <= DELTA2C! THEN KneeC =» TRUE KneeCount = KneeCount + 1 PRINT fCommnum, "Nitrate KneeC detected on "; DATE$; PRINT fCommnum, " at approximately "; TIMES END IF END IF END IF END ELSE KneeA KneeB KneeC Avoid Count SumA! SumB! SumC! IF = FALSE = FALSE = FALSE = 0 = 0 =» 0 = 0 = 0 Search = FALSE KneeCount = 0 END IF IF KneeCount >= 2 THEN Nitrate = TRUE '>= Two knees detected 'Closes If Count <= Ringsize Decision Block 'Closes If Avoid > MaxAvoid Decision Block 'Clear and Reset all the Variables for next Cycle 'Closes Renew = FALSE Decision Block END SUB APPENDIX E CHEMICAL DATA - AASD#1 Chemical Parameter Page Suspended Solids (TSS and VSS) Feed (AASD#1 and AASD*2) 259 Fixed-Time Reactor (AASD#1 and AASD#2) 260 Real-Time Reactor (AASD#1 and AASD*2) 2 61 Nitrogen (TKN, NOx and NH3) Feed (AASD#1 and AASD#2) 262 Fixed-Time Reactor (AASD#1 and AASD*2) 263 Real-Time Reactor (AASD#1 and AASD#2) 264 Phosphorus (TP and Ortho-P) Feed (AASD*1 and AASD#2) 265 Fixed-Time Reactor (AASD*1 and AASD#2) 2 65 Real-Time Reactor (AASD*1 and AASD#2) 265 Dissolved Oxygen Fixed-Time Reactor (AASD*1) 266 Real-Time Reactor (AASD#1) 266 Fixed-Time Reactor (AASD*2) 2 67 Real-Time Reactor (AASD*2) 267 pH, Temperature and Alkalinity Feed (AASD#1 and AASD#2) 268 Fixed-Time Reactor (AASD*1 and AASD#2) 2 68 Real-Time Reactor (AASD#1 and AASD*2) 268 Chemical Oxygen Demand Feed (AASD#1 and AASD*2) 269 Fixed-Time Reactor (AASD#1 and AASD#2) 269 Real-Time Reactor (AASD*1 and AASD*2) 2 69 <J\ o I r t CO </» > - J X < (-N ^ £ o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o • Q 0 0 N N « 0 N « r J N O v t - 0 C 0 - 0 N O O r v J f N J 1 O C 0 f \ J ' O - 0 > 0 O t 0 v f O 0 ) C 0 v t O O O e 0 O ^ t 0 C 0 * O T - ' O r \ i r o r o t n C > ^ ^ c o ^ c X f \ i e o r v i i n ^ o o o r \ | r - h - f o ^ ^ M S - 0 ' v t h - i n ^ < > < > r \ J i n * o r ^ - r \ i ac o n c N ^ « J O O - * i n o ^ c O M ( M t - r - ^ ^ ( \ j o r \ j i - ^ o i n o a ) i o C M n « - i n o » - o o * o > 0 ( M O N M » J ^ s f ^ , O C o K ^ ^ N « 1 j i n ' j N ' 0 4 i n > O i A » o i r i i n ' ^ ' f l i / i > l > o » n i r i ^ i o > O i n i n i n « * - J ooeoooooeocooooocoeoooeocooocooo" o o o o o o o o o o o o o o o o o o O ^ I O O C J ' O O O O O J ' J O O N ^ O ' O W M M ' - M N ' * o g o S M M N O O O i n M O ^ ^ 0 > j O > ' - ( > > j 0 0 » n i n s » v j O v j s j i f > O ' ' O " - i *o r\j o » K >0 O ' M Kl •-I in ro »- x ft) ? X o t_ < I »•-o * •— ft) ro s t/> 3 (0 r o u 4) O U c X U 3C o o > * • ^ / ^ m u ^ • o ^ - o t > ' • 0 ^ » • 0 • l n • I O ( \ J ( \ J O < 0 ( M r v i O N N C 0 0 0 0 4 i o ^ K t i n r o e o r J ^ O ^ * c o c > ^ > h > . h - > N- eg •— o* ~ T tn tn t O O ' O ^ ' O I M O C O s t O O N N s t v O O N t O t O t e o - o o f \ J O ^ O N » , o > » ' O O j n - 1 f w > N M ' - » • o < o > 0 ' © * O m ' O i n m t n * o > O t n u " t i n ^ » » 4 ' * 0 O N O N «- >* ** N- >Ou> o n o *o >* «- Q O A r a r a & r a Q r a 4 T O r a & r a r a Q ^ B ^ u 4 ( 9 < 3 ^ i Q r a & n 3 r a f f l ^ n < 9 r e r a n r a i ? i T } i i rtJBfflrS3u.S<9roroQroCLrororo(63 O * o e o o > o * - 0 " e o o * - o « - - ( O O i - O t - C ^ N ' - O O O O O 1 • O « - O O 0 0 O 0 * O O » - « ~ r - r - o . o e o o T - r \ j o o o o o * - T - o « - o « — o » - N M N » i n > O N e o O k O ' . - c — • x ra C "O 10 *l • - w X X X V ) SS888RRRSRRRRfcl5RI2RS8RRSRSRRRRR o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o ' o o o o o o o o o o o o o o o o o o o o o o o o o o o o *0 5 e O N 0 8 0 W [ M ' | ' * » O O s } * Q * Q f i O ( M ' 0 ^ * J ' O N ^ ' 0 « W ( M O t O v O • • ^ « 0 0 N O W s l N j e 0 0 0 C 0 N s t ^ ^ 0 0 r j ( 0 C 0 C 0 C M ' 0 N O ^ N * O v 0 ** N M ^ ^ N ^ M N T - N O i n O t - n S ^ i n s j N N ^ ^ f s . p ^ M ' - n n > i M i n r j N * r j ^ c o ^ ^ r 4 r n r n f n f N J K i ' > o o > N . o * - i n i n r g < > o » r - . s j f \ j £. ^ ' 0 * * ' * ' s t » O N i n i / i S ' O i n « n i n i n v * « O N ( > D i n i n i O i r > ' O i n , O i n e o K - • • < 0 ( > i n i n i n N S < 0 0 < 0 , 0 < o K ' < O i n N i n 4 ' O N ^ s t ^ i n > f ' O N n n o " • N i n o . «~ r- Kl o i n f f l O f O O « * W N N n i r t i n o i n o N a p N e O N > * t O O * 0 0!Jog«0 0 ' 0 5 ' O C O > t N ' * O O C O i t O N * * « J 0 0 ^ M 0 0 0 0 ^ N N O « | O , 0 0 J ^ « * v t N O < t ' O r \ J ' 0 , O e 0 R f O r ^ ° ^ ^ c 5 r , N i n c O i n N N - O M ' O O O i n i n r o i » o o o t n o o > Q i n o c o c o o o o < 4 p < c h S - > o t - ( O N i r < { > N t > 0 ' < t p > S > c g > o ( > N . r * > o ^ O N O ^ o o o t > r - r i n K - N N . S . r « - ' O o O ' O o o t i o o < - > o « , 2 o o h N ( O c o D O O > s o i > N > o s o o i n i n s < d s i n < o § •*- w 5 Q S § i 4 a a l S Q . a S a a S S S S S a . i i S S § S Q . Q . S a S ! ! S a S a a a s S a S ! ! S S a a S S S S S s S S S S S S ° V ••" C __ __ __ i t i t *- 00 *- T- O r- f\J N N in >Oinoo o o *- eg «o in %T oo rsj in co «- O n N i n ' - E o -g > ro o o o o i ooooeooorsjrvfMeorsJNaor>jf\ jeoeoeocoeorMO>eococaeocorNJr\jOtoeo • or \ joor \ i ( \ jn jeo(>->or<- « B N N C > e o t - o o e o o S K o o { O S i«* i n > o K » t > O i - r j i l r - N K | ' * i n , O N t - N r o s t i n v O M o o > o » - N i c — • m C T3 260 AAS0#1 DAY 1 2 3 4 5 6 7 8 9 10 11 12 FIXED TIME REACTOR SUSPENDED DATE Sailing MLSS Jun/19/90 20 21 22 23 24 25 26 27 28 29 30 13 Jul/01/90 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 31 Jul/19/90 32 33 34 35 36 37 38 39 40 41 42 43 20 21 22 23 24 25 26 27 28 29 30 31 44 Aug/01/90 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 Maximum Mean Minimum 02 03 04 OS 06 07 08 09 10 11 12 13 14 15 16 17 Std. Dev. Time (Hr:Min) 12:00 pm 10:35 am 10:15 am 1:30 pm 6:00 pm 5:30 pm 1:20 pm 11:10 am 1:50 pm 2:00 pm 2:15 pm 3:00 pm 6:15 pm 3:50 pm 10:00 am 9:10 am 10:15 am 11:50 am 3:50 pm 3:40 pm 2:20 pm 10:40 am 3:10 pm 9:35 am 1:15 pm 2:40 pm 3:05 pm 10:15 am 12:35 pm 3:15 pm 1:15 pm 3:15 pm 12:45 pm 4:00 pm 12:15 pm 1:10 pm 5:15 pm 3:55 pm 10:30 am 1:15 pm 7:45 pm 11:25 pm 1:40 pm 12:35 pm 4:50 pm 4:00 pm 1:30 pm 10:50 pm 1:20 pm 1:30 pm 1:30 pm 1:45 pm 1:25 pm 1:55 pm 2:15 pm 8:15 am 1:30 pm 2:20 pm 9:30 am 8:30 am (mg/L) 5716 5598 5790 5524 5436 5336 5376 5924 5866 5712 5938 5826 6100 5854 5826 5852 5878 5970 6278 6724 6980 6818 6774 6752 6666 6702 6568 6530 6604 6960 6980 6800 6856 6956 7416 7172 7006 6954 7028 7370 7472 7322 7084 7140 6792 7052 7252 7088 7456 7216 6904 6826 7082 7278 6960 6756 6628 6516 6646 6270 7472 6569 5336 600 SOLID CONCENTRATIONS MLVSS SOLIDS (mg/L) 4496 4412 4552 4358 4252 4154 4216 4728 4632 4454 4606 4510 4704 4506 4490 4508 4522 4602 4864 5204 5416 5298 5272 5236 5192 5202 5088 5046 5084 5400 5388 5240 5284 5370 5718 5428 5406 5380 5424 5702 5812 5692 5468 5498 5228 5452 5566 5418 5732 5538 5274 5266 5456 5584 5330 5152 5058 4994 5090 4818 5812 5080 4154 442 RATIO 0.79 0.79 0.79 0.79 0.78 0.78 0.78 0.80 0.79 0.78 0.78 0.77 0.77 0.77 0.77 0.77 0.77 0.77 0.77 0.77 0.76 0.78 0.78 0.78 0.78 0.78 0.77 0.77 0.77 0.78 0.77 0.77 0.77 0.77 0.77 0.76 0.77 0.77 0.77 0.77 0.78 0.77 0.77 0.77 0.77 0.77 0.77 0.76 0.77 0.77 0.76 0.77 0.77 0.77 0.77 0.76 0.76 0.77 0.77 0.77 AASD#2 DAY FIXED TIME DATE 1 Oct/02/90 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 31 Nov/01/90 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 Maximum Mean Minimum 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Std. Dev. REACTOR SUSPENDED Sampling MLSS Time Hr:Min 2:00 pm 10:20 am 2:05 pm 2:00 pm 2:40 pm 2:15 pm 12:55 pm 11:25 am 1:30 pm 2:40 pm 3:00 pm 4:25 pm 2:30 pm 11:45 am 3:05 pm 12:55 pm 1:05 pm 3:20 pm 11:05 am 3:20 pm 2:20 pm 1:30 pm 3:30 pm 1:35 pm 2:55 pm 1:20 pm 6:10 pm 1:10 pm 2:05 pm 1:10 pm 4:45 pm 7:40 pm 4:40 pm 5:50 pm 2:50 pm 1:05 pm 1:55 pm 2:10 pm 12:45 pm 1:10 pm 10:30 am 1:15 pm 4:50 pm 2:00 pm 1:20 pm 6:55 pm 1:15 pm 4:05 pm 1:20 pm 3:15 pm 1:30 pm 2:05 pm 9:30 pm 3:45 pm 3:30 pm 1:45 pm 12:25 pm 12:10 pm 12:15 pm 11:05 am (mg/L) 6332 6678 6772 6468 6554 6340 6324 6242 6266 6374 6654 6382 6470 6502 6366 6394 6148 6046 6248 6196 6168 6194 6254 6154 6146 6212 5988 6066 6064 6034 6006 6104 5972 5916 5856 5970 5916 6078 6038 5890 5932 5946 5830 6026 5984 5814 5842 5650 5738 5760 5760 5588 5288 5330 5368 5196 5208 5248 5036 4904 6772 6039 4904 362 SOLID CONC MLVSS (mg/L) 5032 5316 5350 5148 5204 5032 4966 4912 4930 5060 5268 5096 5162 5176 5092 5132 4934 4830 4978 4952 4956 4982 5018 4954 4906 4988 4784 4852 4850 4846 4802 4910 4772 4722 4676 4802 4760 4864 4850 4716 4762 4764 4680 4834 4796 4664 4682 4562 4581 4624 4612 4492 4238 4266 4284 4122 4146 4208 4074 4042 5350 4826 4122 281 :ENTRATIONS SOLIDS RATIO 0.79 0.80 0.80 0.80 0.79 0.79 0.79 0.79 0.79 0.79 0.79 0.80 0.80 0.80 0.80 0.80 0.80 0.80 0.80 0.80 0.80 0.30 0.80 0.81 0.80 0.80 0.30 0.80 0.80 0.80 0.80 0.30 0.80 0.80 0.80 0.80 0.30 0.80 0.80 0.30 0.80 0.80 0.80 0.80 0.80 0.80 0.80 0.81 0.80 0.80 0.80 0.80 0.80 0.80 0.80 0.79 0.80 0.80 0.81 0.82 p s 0 O 0 p - O 0 p » ^ 0 0 O 0 0 O O O O O 0 0 r - T - 0 0 O 0 O O O 0 O O 0 O O O 0 0 0 0 O 0 0 r \ ) r - O 0 O O O 0 0 0 O 0 O 0 ' - r \ J N c o a } o ) S c o o o S N - ( o e o o o < o o o t O f l O c o c o ( O c O ( O e o o o ( O c a e o a ) a ) c n c o e o c a a } o o ( o o o o o c Q e o c o e o ( 0 ( O o o o o c o a } i o n O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O N N N C 0 ' * N O ^ ^ N O a O v » r y v 0 O C 0 ^ O N ^ ^ N ' 0 N ^ i n O O O C 0 ^ N f ' 0 » N < 0 C 0 N C 0 ^ N t ' 0 e 0 N O N N s * O C 0 C 0 ' 0 ' J ^ O ~ . - ~ ~ i ~ . _ ~ — ~ _ . - j r - ^ K » ^ ^ i > o o o ' 6 ' 0 0 0 ' N N ' 0 ' o K * o S N K N ' 0 ' 0 > o N ' 0 » n i n < M ^ i n i n ^ n n v J M M O r - r - o o m tn i n m *  •-* * * o -4- co o - ' - - - ~ in r\j r\j o o o ro -t m rg oo >t N- ^ sf in *o ^ r*. o m in -* K» J o o o - ^ f v j r M O o r v j f M oo m r^ f\j — *0 *0 *0 "O •© *0 *0 *0 ""O N e 0 r 0 N c g N O 4 ^ O 0 0 O O ^ N j r J ^ ^ s t N < l N ^ 0 0 O v t O ^ « N O e 0 O O N e 0 * » O « - * * N v O O ' * N f C 0 f \ J N 0 0 C 0 N ' O ( \ l ^ N ^ ^ J n ^ 4 > * ^ M N N N n N » - c o o > c o ( 0 0 » e o ( > r a o - o > S o 3 c o o 5 N ^ ^ ^ - * i n i n » o i f l s t s t i n > * v j O ' - ' - o o ( > 0 ' N O r - N O rg m ^ S S o o -sj in >* &§&&&&£§&S.&S.&! l&&a&!5&&&g.S.&&£&&&&&&5.&&&5.S .&§S.S .S .g .g .&&&&&&&8.&&&&S.§ N o r \ ) N N N » - » - t - r \ i M N r N r - n r - r - n » - M r s j T - K t ' - K i T - - o p - r o » - ^ N f o i ^ N r - r - ( \ j t - f - 0 ' - i n N « - N » - r o * - r O ' - N ( > i i «- r\j rvj C\J o > r - { \ J M ^ l f l ' O S e O O O « - N M ^ i n » O N e O O ' 0 * - » - N M > n n ' O N C O « > O i - ( M l i - f f f - T - i - T - ( M N N ( V N N N N ( M N M M O O O O O O O O O r r » - > « - r \ j M » * i n « o r ^ t o o o « - f M i 1 ^ i/>>0 S C O o o X <!J C TO <o at — *-< o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o a o o o o o o o o o o o o o o o o o o o o o o > * n ^ n ' - » - n i f i i f t n ° "* St * * y j >o ' O l T K O O ' O O N» sr CK N i n j * l O ^ ^ w o o o e O ' O i . j ^ t o i o N ' - ^ M N ' - N o a e o * , _ . _ . _ . . . _ _ _ . _ _ O ( O ( 0 ^ O 0 0 N < 0 O N O ( M O N ^ ( 0 O < O ( 0 O , O N e Q f > j r * - 0 ( M O S - M O - » * r - - ^ T - ( > O i n O r M O O O " " " * ._ - - • , - m r-* -o - ' 1 - O C M i n l M - ^ r O K I ^ f M •O «M CO Q O ** - ^ CM CO CO « N- CO -d M c\j K I i n « - o O SS2 P J i n >0 CM * - o * - ro r- o • - •** m m * * o ^ o o o e o ( g p < o < o o o o < 4 ( o « i ) > t s t ( O N o < « o o ' 4 0 s t ( o e o ( o o o c o o N o c o e a v i } ^ ^ e a ^ < o « g i l n * o ^ K » f ^ J f o ^ . ^ w | n ^ ^ Q Q * o o c o y ) ' 0 « - • m < n i n i n i n i n i n i A i n m i n > o < O r " S 'V *^ *V '** "V •"" in •Ominin >o o ^ o o ^ o ^ t o e o t o > o e o o N O c o o o « o > t ^ e o % t ^ y ) r j N O N c o > o 4 < < { < o ^ N « o ^ c o » n O T - « O s * i n ^ N N s | v t ^ M C O O f O f v i S N o w N o e o 4 c o ^ ( > » - i n w ' O O N i n ' O S «2 o «> t o ^ K i n g - M i n » o N ( > ^ N r - o g K < > ^ n f > l o 3 ^ c 9 p p ^ N e D ( > a ^ [ N i c o ^ N . « N ^ « > 0 ^ y ) « > 0 ^ 4 N < l ^ « N N v ^ ^ S S > h * ' o S , 0 N S > 0 S ' 4 t 0 ' 0 N r * x ) , 0 , 0 - * CM *o fM S « o - o 3" Is- m •o wo O «~ CO «- s j in N ^) o o i n o o i n o i n o i n i n o o i n o i n i n i n i n o i n i n o o o o i n o i n i n o i n o i n i n o o i n i n i n o o o m i n i n i n i n o i n o t n i n o i n o o i n o o t - i n N o o - * M v » i o o o g ^ a r - i n N ^ N O N r \ i « - w i n N K i n r - > t o N O ^ ^ i n o ^ o ^ i n N K i o o » - ' i o o n * " O i n n ' N i M M ' - N r > J r \ i o o n j K u ^ » - o r \ i « - - * r \ i * o ^ o e o o « ~ M r > j r s i o i n O ' f > j f > J r j f v c > j r \ j f \ j r o ^ r o r - r ^ o p o o «- CM K» *tf i n «0 I i ^ i n > O N e o o o » - N n > » i n ' O K e o o < 0 ' - N i i > f m < O N ( 0 0 > 0 X CO C "O ffl « ' r - M X X X CO 0 0 0 © 0 0 0 0 0 0 0 0 0 « - 0 0 0 0 0 0 © 0 0 0 « ~ 0 i o o o o o o o o o o o o o o o o o o o o o o o * - o o o o i n i n * * « - r - O N o * - o r \ J o m i \ i o » - o o « ~ * - o < M - * r \ i o r o o o o » - f \ i o * o o o » - o o o o o o o o o ' 0 » - r M f o m f \ j o » r » ' 0 ^ » ^ o e o r - r v i r o ^ r o f v J M f M o o o o r o c 3 > * O K > » - o o r o » - o o o o _. • t n d v t » - r \ i i n o i n o i n r M r j n M N ( v J i n i n » - 1 - ( O o i r » i - « * M , 0 » n * t * * i / i ^ i / i t n ^ s t i n i A ' j , O i n * * N * s * i n i r « i n > j M ' * v» O v j OJ R c o o o i m u " i U " » m o O i r t o m o o » / > o o o i n t / > t n i v » r - Q O ' - O O M ' - i n O - * M M O ' - f V J ( M m » - ' O i n ' O n > t M n K i ' O S N « o i n ( N j ^ « n r o r o r O f O i n » o e o i n i n s t M M , o « - ' O i O i n M r N s r m a N < o n i n i i N j - i M ^ f M ^ t - r y * - * - K « C T> o» «o co ru eo ro • r \ i N O r o N * o o o o o o « - r \ i r u * - o c M O o o o o o o o o o o o N O f ^ O O O O O O O O O O O O O O ( \ l m S ( D « - 0 « ( V j K ' 0 « ) N C 0 !tC t r » m m * - f \ i h - * ^ » -Kfc; v» *o »o I l « r j * J i • N N O i n m o O K ) ^ ' - » - * - M O O O » - r o r » j o o ' 0 * - o m N . i l O O O O O O O O O O O O O N N K i m i n K i C M / i t o i n r s j f N j f O u K o o o « - o o m o r - f \ i o o o o o o m c \ i « j , o r « J H > r j » / * r > o h - N O ro NO *- *- m ^t fO »- m o i n i r t i n o o o o u i o o i n o o o i r t m o u t o o m m m o o o i n o i n n o n - * ( O r o M O r j o ^ N n i n i n O f v j o o K > 0 ' - M i n n i n ' - i n n K I N C N i m ^ i A » - N N » - ' 0 0 ' * S " r - O N K ) > * i n i / 1 f V l N r - > * N I \ J n r y " 0 i i - r s i r o > t i n ^ } ^ c o o < o ^ r s i r o ^ i n ^ N - o o ( > o ^ N r o ^ i n ^ ^ o o o > O r - r J K > ^ i n ^ ^ o o ( > o ^ ^ r v J r o s r u ^ < > ^ I N N N N N r \ I N W ( \ I M O O O O O O O O O ' - » - i - r - i - r - t - » * ^ r « N O J N N f g N N N ( \ l ( \ J M f O O O O O O O O O O r - t - ^ r - r - ^ f - r i - ^ i r t N O N - e o o o ' - i M i K 10 C D (D 4» •— *-* i - ^ r - r - ^ o ^ r J ^ e o N S « ( y ^ O « o > t O N i n i - c o o o ^ N M ^ n f v J > * ^ S N » - 0 » i n e o » - ^ N y ) * 0 ^ $ i n S ^ C h N ^ i n O t - 5 N i n M 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 > » 0 n i n M O O ' O c o ^ ^ N T - o ^ o * - i f t c o « ^ « M N t O N f N t ' - c > o o M ^ N S ' 0 ^ t f i 4 0 ( > N ^ u i m i n o ^ i n » o o ^ ( > w n ^ - 4 S i ' i n * o o c o ^ r j ^ r s J O ^ ^ ^ o ^ e o ^ ^ ^ ^ t ^ c o ^ r o r g r o o ^ ^ r O ' - o i n ^ ^ r v j ^ ^ ^ n ^ N O O o e o ^ c o ^ ^ r * 0 » - » - « - O 0 r - O 0 t - O r - O * - O 0 ' - ' - ' - 0 O r O « - 0 t - O 0 N ' - O r - t - O > t r f - t - ( \ I O r M f ( M ' - r * ' - N O » - O N « - ' - r - O ' - N 0 0 o o o o ^* * - o o i n i n i n i n i n >i • • > t > t s t > * - * ^ ^ ^ > t N * ^ ^ N * s t > f s t s t N j ^ ^ > t > * N t > f ^ s t » * N * > f ^ ^ ^ > * f o ^ > » s t * * n K ) M r o M n r o M i CO «- fM CO CM - * i n fo r - ^ r - r - N r - N O N O O f M N M O O O N " ( V O ( M » - f y O « - f - N [ M ^ r - ^ ^ N N O 0 O N f \ J N » - ( M N i - 0 0 O 0 ' K > o r \ j f v j « — o * - *— • - r*i S H- C C C C *•- H- **- C H- *•- C **- * • C C C **- C C H - C *+- C H - <•- »»- •*- **- C "*- C C "•-*•- s- *•- C C **- C M - C C C C C C C *•-«+-**- *•- «•- C H - H - H - C o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o i s t i n ^ O N C O O O « - i > j i « - r N * M ^ i n ^ ^ e o o * o ^ W K i ^ i n * o h ^ a » o * o ^ r v j r o ^ u ^ ^ K c o o » o ^ r > j r o s f i n * O N - c o < > > o « - - r \ j i ' ^ r m i n m m m t n m m i n t n ' < o ^ e o c o o ^ o » T - K « - o o o K o o o o * - o o o r \ j o o c > o o o ^ o ^ . » - f o O ' - f o o r ^ ' - o o o o o e o i n o ( > o o o o « ~ o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o l O N N i n r m i « - O O ( M f - O f - 0 N N N N O N r M i • r g N O C N ) » - « - O t - 0 « - r - r - i - r ' » - 0 » - N r O T - f y r - O t - N O ' - < \ » « - » - « # N r M r g « - T - f N J » - *o »* CO *o < 0 > o o a %r «- o o S5SSSR3iaasS5SS§SS55B333933333S55355^555555553*S52HSS33323 i n vn co Kl -o m N. •J- * * (M SSS5S5S55S5S5S5SSSg5S555555S55S5SS55SSS6SS5SS5g l sSS5SS55SSSS i • - rsj tn -* in *o r* i - r v j n ^ i A ^ o s o o ^ O T - N n > * i n ' O N c o O ' O i - N M ^ i n ' O N e o O ' O t - p j n * t i n » o s c o o > 0 ' - p J M N » i n M 3 N ( 0 ( > - 0 ' - N M ^ i A - o N o o o > o 264 AAS0#1 DAY REAL DATE 1 Jun/19/90 2 3 4 5 6 7 8 9 10 11 12 20 21 22 23 24 25 26 27 28 29 30 13 Jul/01/90 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 31 Jul/19/90 32 33 34 35 36 37 38 39 40 41 42 43 20 21 22 23 24 25 26 27 28 29 30 31 44 Aug/01/90 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 Maximum Mean Minimum Std. Oev. 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 TIME REACTOR EIapsed Time Since Air ON (Hr On On Off On On Off On On On On On On On On On On On On On On On On On On On On On On On On Off Off On On On On On Off On On On On On On On On On On On On On On On On On On On On On On or OFF :Min) 1:25 0:20 0:45 2:45 1:05 2:55 2:15 1:35 1:30 1:35 1:30 2:10 1:30 0:20 1:45 2:00 1:40 2:00 0:35 1:50 1:40 1:40 1:30 1:50 1:50 1:40 2:35 1:45 1:55 1:30 0:40 2:15 1:15 1:20 2:00 2:25 1:05 3:00 2:05 1:50 1:35 1:30 1:30 1:40 1:15 1:40 1:20 1:20 1:30 1:40 2:00 1:50 1:35 1:40 2:55 1:40 1:05 1:35 2:30 1:35 NITROGEN TKN <mg/L) 359 368 401 323 351 348 350 368 358 402 402 387 403 414 414 376 346 338 394 429 466 438 473 460 440 424 451 425 408 439 450 489 447 445 476 474 422 457 471 500 491 462 434 450 464 473 483 475 464 472 430 449 440 495 448 449 432 448 432 391 500 428 323 44 CONCENTRATIONS NOx NH3 (mg/L) 1.74 0.83 1.55 0.14 1.74 0.22 2.27 1.80 2.00 2.11 1.88 2.38 1.78 1.12 1.85 2.03 2.59 3.65 2.03 f.38 1.50 1.50 1.50 1.74 1.68 1.45 1.78 1.30 1.43 1.15 1.59 0.76 1.22 1.12 2.17 4.18 1.81 0.17 1.77 2.18 2.03 2.01 2.00 2.12 1.59 0.04 1.60 1.98 2.34 2.22 2.39 2.31 3.20 2.54 2.36 2.32 1.75 1.91 2.55 1.90 4.18 1.80 0.04 0.73 (mg/L) 0.08 0.22 0.49 0.92 0.10 0.90 0.13 0.13 0.14 0.08 0.10 0.07 0.10 0.13 0.10 0.11 0.11 0.07 0.07 0.07 0.10 0.08 0.10 0.09 0.10 0.11 0.13 0.10 0.09 0.08 0.20 0.74 0.08 0.10 0.09 0.09 0.09 0.61 0.10 0.10 0.10 0.10 0.09 0.10 0.11 0.10 0.11 0.11 0.11 0.12 0.11 0.11 0.11 0.12 0.12 0.16 0.11 0.10 0.11 0.10 0.92 0.16 0.07 0.18 AASD#2 REAL DAY DATE 1 Oct/02/90 2 03 3 04 4 05 5 06 6 07 7 08 8 09 9 10 10 11 11 12 12 13 13 14 14 15 15 16 16 17 17 18 18 19 19 20 20 21 21 22 22 23 23 24 24 25 25 26 26 27 27 28 28 29 29 30 30 31 31 Nov/01/90 32 02 33 03 34 04 35 05 36 06 37 07 38 08 39 09 40 10 41 11 42 12 43 13 44 14 45 15 46 16 47 17 48 18 49 19 50 20 51 21 52 22 53 23 54 24 55 25 56 26 57 27 58 28 59 29 60 30 Maximum Mean Minimum Std. Dev. TIME REACTOR EIapsed Time Since Air ON or OFF (Hr:Min> On 1:55 Off 1:35 Off 0:30 Off 0:45 On 1:25 Off 1:15 On 1:55 On 0:25 Off 1:15 Off 1:30 Off 0:55 On 0:35 On 0:35 On 1:20 On 0:45 On 3:55 On 0:25 On 1:30 On 0:10 On 0:35 On 2:15 On 0:05 On 1:05 Off 0:20 Off 1:00 On 0:30 On 1:00 Off 0:50 Off 0:45 On 1:35 On 0:30 On 0:05 On 0:55 On 0:05 Off 0:30 On 1:35 On 0:10 Off 0:35 On 0:05 On 0:05 On 0:15 On 0:15 On 0:05 On 1:40 Off 0:50 On 0:15 On 0:05 On 0:10 On 0:05 On 0:10 Off 3:00 Off 0:30 Off 0:30 Off 0:55 On 1:15 On 0:25 On 0:10 On 0:15 On 0:35 Off 4:00 NITROGEN TKN (mg/L) 525 473 530 498 472 462 478 456 455 467 479 461 470 475 463 470 432 441 435 455 437 444 446 446 437 439 452 438 427 407 446 442 429 429 425 418 439 404 430 408 414 401 395 409 402 376 411 402 396 391 385 386 354 369 358 350 364 336 345 354 530 430 336 41 CONCEN NOx (mg/L) 2.01 0.19 0.51 0.19 0.91 0.16 0.37 0.44 0.19 5.05 1.04 0.61 0.44 0.96 0.56 0.60 0.37 1.06 0.47 0.57 1.32 0.28 0.37 0.47 0.35 0.57 0.94 0.59 0.30 1.08 0.50 0.28 0.75 0.31 0.66 2.69 0.47 0.42 0.14 0.26 0.67 0.61 0.99 1.74 0.25 0.81 0.34 0.38 0.27 0.57 0.15 0.60 0.68 0.69 1.28 0.96 0.49 1.28 0.15 0.30 5.05 0.73 0.14 0.74 [•RATIONS NH3 (mg/L) 0.05 0.35 0.09 0.29 0.05 0.26 0.10 0.07 0.24 0.35 0.19 0.03 0.03 0.03 0.02 0.04 0.02 0.02 0.09 0.04 0.04 0.12 0.04 0.09 0.27 0.06 0.08 0.15 0.17 0.06 0.05 0.19 0.05 0.10 0.10 0.34 0.10 0.17 0.21 0.30 0.09 0.27 0.89 0.07 0.23 0.08 0.16 0.23 0.32 0.32 0.57 0.15 0.16 0.20 0.07 0.32 0.22 0.07 4.99 10.58 0.89 0.16 0.02 0.15 265 DAY 1 2 3 4 5 6 7 a 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 OATE J u n / 1 9 / 9 0 20 21 22 23 24 25 26 27 28 29 30 Jul/01/90 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 Jul/19/90 20 21 22 23 24 25 26 27 28 29 30 31 Aug/01/90 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 Max i nun Mean Minimun S t d . Oev. AASOHM F TP 220 241 164 214 205 271 307 250 216 352 294 279 259 246 259 246 308 354 410 472 252 262 261 276 292 263 301 246 413 366 — — 325 445 261 271 279 385 429 330 345 320 340 344 399 361 301 332 332 276 347 415 323 265 250 364 294 375 253 295 472 306 164 64 PHOSPHORUS MEASUREMENTS EED 3rtho-P 8.47 0.20 0.53 5.60 8.76 18.78 6.26 0.20 6.94 1.76 12.46 0.45 19.23 11.64 0.28 0.28 0.45 5.07 27.18 30.85 18.94 0.45 25.13 0.36 17.96 7.45 1.77 2.11 2.03 18.76 15.48 31.70 10.45 0.00 4.14 4.06 0.00 0.00 0.00 4.48 16.26 23.40 23.04 12.19 0.64 27.88 0.38 0.00 0.64 3.78 18.37 0.00 11.50 0.00 6.59 11.94 0.00 0.00 31.70 8.40 0.00 9.27 FIXED TIME REACTOR TP 186 218 211 210 226 164 216 234 230 261 265 259 277 260 258 263 269 270 259 277 297 292 292 286 309 287 289 292 311 341 326 354 346 342 385 344 344 334 343 353 358 321 325 329 329 333 323 328 347 328 329 332 348 359 355 339 344 332 346 338 385 300 164 49 O r t h o - P 23.82 28.43 39.46 35.90 43.88 46.38 47.38 47.38 50.73 52.18 53.38 54.33 55.18 54.33 50.73 50.00 48.53 47.23 48.90 48.53 46-40 45.55 49.13 48.05 46.27 44.59 44.90 43.33 43.22 40.70 42.80 45.74 53.84 46.69 41.58 40.53 40.11 38.75 35.07 35.38 36.01 33.49 34.22 32.96 44.53 43.65 41.91 47.36 44.53 44.31 47.47 49.21 50.21 53.93 55.04 53.93 60.43 59.50 57.55 61.54 61.54 45.85 23.82 7.59 RE AL TIME REACTOR TP 199 205 225 199 216 215 219 231 230 256 251 247 264 254 258 275 255 252 254 265 289 279 298 293 280 274 288 271 326 341 346 370 373 359 369 361 331 351 350 376 385 320 309 320 334 338 338 351 341 350 328 343 333 364 349 349 363 361 348 333 385 302 199 53 O r t h o - P 25.00 28.80 33.02 46.18 45.40 46.32 48.30 49.68 54.08 54.68 56.23 51.08 55.10 53.30 51.58 51.93 48.78 49.38 48.65 46.40 45.08 44.00 48.90 46.28 44.06 44.27 41.96 39.75 37.23 36.28 36.60 43.01 42.17 46.48 36.64 35.07 36.96 51.68 40.11 38.85 38.54 37.38 37.48 37.48 37.77 37.66 36.14 39.52 35.48 33.96 36.90 35.16 35.53 36.18 39.25 39.34 40.83 42.68 42.68 44.08 56.23 42.39 25.00 6.79 DAY DATE AASD#2 TP PHOSPHORUS MEASUREMENTS FEED FIXED TIME R Ortho-P 1 Oct/02/90 287 7.40 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 322 0.22 237 18.14 191 2.58 177 0.31 175 0.07 199 2.41 134 0.81 330 2.19 42! 20 24! 30 165 203 151 264 243 184 206 225 193 242 222 202 185 256 242 198 297 31 Mov/01/90 241 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 Maximum Mean Minimum Std. Dev. 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 210 186 202 238 223 221 210 169 193 . . . — 224 222 200 208 204 185 201 180 198 187 237 223 205 196 185 134 116 152 425 215 116 50 0.16 1.13 9.64 0.17 8.88 4.82 0.92 5.45 7.79 0.07 0.48 0.18 0.19 8.91 4.29 3.82 0.07 8.25 0.25 0.14 0.07 2.83 8.07 1.84 8.04 8.04 0.09 0.08 2.75 0.09 0.09 9.53 0.35 0.12 8.18 0.08 0.07 0.06 0.99 0.10 0.10 22.26 1.03 0.08 0.12 0.09 2.49 0.31 0.57 22.26 3.07 0.06 4.54 REACTOR TP 297 301 306 306 297 287 290 289 279 292 278 281 289 278 296 273 273 287 279 274 267 270 275 281 267 271 271 263 274 272 216 230 227 220 226 228 231 223 218 223 248 244 245 254 242 244 240 240 245 245 248 246 248 241 245 243 235 243 231 231 306 260 216 25 Ortho-P 48.41 51.02 49.89 52.24 52.51 51.72 53.38 54.25 53.81 53.38 60.21 57.40 59.55 58.23 60.78 59.63 59.13 61.03 59.79 60.21 59.88 61.61 62.10 59.96 60.95 61.21 63.20 60.26 61.47 61.13 60.87 60.61 61.47 60.87 62.34 59.92 57.50 59.97 59.35 59.44 58.10 63.99 73.09 65.86 61.22 63.10 60.87 62.56 61.58 61.22 64.97 64.17 68.40 64.62 66.41 65.28 66.70 65.75 78.30 88.68 73.09 60.15 48.41 4.63 TP 306 286 317 304 293 292 298 280 283 288 291 283 286 287 283 285 271 273 268 274 269 267 273 272 267 273 274 270 267 267 230 229 222 222 226 218 226 215 223 212 242 241 245 244 237 228 238 237 237 235 249 245 235 239 237 232 240 231 227 222 317 258 212 27 EAL TIME REACTOR Or tho-P 47.71 52.51 56.26 58.18 59.74 60.97 58.61 58.96 60.79 59.48 60.45 61.36 60.62 61.44 61.35 61.85 62.76 62.93 61.44 63.83 63.59 63.09 63.83 63.50 62.16 62.16 64.84 63.20 64.93 64.06 64.93 64.24 64.50 63.98 65.71 63.20 63.37 60.96 62.47 62.92 62.38 68.81 75.94 70.87 68.63 65.77 65.06 64.97 67.91 65.95 67.65 67.74 67.08 66.70 69.81 70.28 70.76 67.17 79.34 90.76 75.94 63.56 47.71 4.38 266 DISSOLVED OXYGEN MEASUREMENTS 'AAS001I FIXED TIME REACTOR DISSOLVED OXYGEH MEASUREMENTS AASO#1) REAL TIME REACTOR DAY 1 2 3 4 5 6 7 a 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 DATE Jun/19/90 20 21 22 23 24 25 26 27 28 29 30 Ju1/01/90 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 Jul /19/90 20 21 22 23 24 25 26 27 28 29 30 31 Aug/01/90 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 Max i nun Mean Minimum Std . Dev. Sampling Time o (Hr:Min) 12:45 pm 1:00 pm 1:05 pm 1:45 pm 7:00 pm 2:35 pm 1:15 pm 1:30 pm 1:40 pm 1:55 pm 2:00 pm 2:50 pm 2:50 pm 10:05 am 9:55 am 8:55 am 10:10 am 9:55 am 3:45 pm 3:50 pm 2:15 pm 9:55 am 10:00 am 9:25 am 9:05 am 2:35 pm 2:35 pm 9:35 am 9:45 am 10:15 am 9:50 am 10:30 am 10:30 am 4:10 pm 10:55 am 10:30 am 5:05 pm 11:40 am 5:50 pm 11:55 am 6:15 pm 7:40 am 1:00 pm 12:30 pm 12:45 pm 12:45 pm 12:55 pm 7:45 pm 1:15 pm 1:25 pm 1:30 pm 1:40 pm 1:45 pm 1:50 pm 2:00 pm 8:00 am 9:00 am 2:15 pm 9:15 am 8:30 am Length f Time of Aera t ion (Hr:Min) 2:00 2:00 2:00 2:30 1:30 3:00 1:30 1:30 1:30 1:30 1:30 2:00 1:50 2:50 2:30 1:30 2:00 2:00 1:30 1:30 1:30 3:00 3:00 2:15 2:30 1:00 1:00 1:45 1:45 2:15 1:30 2:00 1:75 1:30 2:00 1:30 1:00 1:30 1:30 1:30 1:30 3:00 2:00 1:30 1:30 1:30 1:30 2:00 1:30 1:30 1:30 1:30 1:30 1:30 1:30 1:30 2:30 1:30 2:20 1:30 A i r f l o w Rate (mL/min) 154 154 154 161 154 154 151 154 154 151 161 151 161 154 151 151 151 146 146 143 154 146 146 146 143 146 149 144 143 146 146 151 146 149 144 146 154 151 165 151 165 165 151 151 146 154 154 151 158 149 151 151 154 161 154 154 151 154 149 154 Dissolved Oxygen DAY Concentrat ion (mg/L) 2.50 2.00 2.00 2.30 2.60 2.85 2.70 1.75 2.60 3.20 3.85 3.20 4.00 4.20 4.00 4.45 4.90 5.20 4.60 2.80 3.20 3.20 3.10 2.10 3.20 2.80 2.70 4.45 4.10 2.80 1.90 4.05 3.80 2.20 1.40 2.80 4.45 5.30 4.05 3.75 3.80 3.90 4.40 4.40 4.30 3.70 3.05 2.40 2.85 2.70 2.90 3.00 2.90 1.80 1.60 2.15 2.40 2.70 2.70 3.05 5.30 3.20 1.40 0.93 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 DATE Jun/19/90 20 21 22 23 24 25 26 27 28 29 30 Ju l /01 /90 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 Ju l /19 /90 20 21 22 23 24 25 26 27 28 29 30 31 Aug/01/90 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 Maximum Mean Minimum Std. C ev. Sampling Time (Hr:Min) Length of Time of Aerat ion (Hr:Min) 12:45 pm 2:00 12:30 pm 2:00 1:45 pm 2:00 11:00 am 2:30 7:25 pm 1:30 2:30 pm 3:00 1:15 pm 2:00 10:45 am 1:30 2:30 pm 1:30 1:00 pm 1:30 4:00 pm 1:30 2:45 pm 2:15 6:40 pm 1:50 12:35 pm 2:50 9:55 am 1:30 8:55 am 2:00 10:15 am 1:30 11:45 am 2:00 3:20 pm 1:30 1:40 pm 1:30 2:15 pm 1:30 10:15 am 1:30 1:15 pm 3:00 9:30 am 1:30 1:00 pm 2:00 2:15 pm 1:30 2:35 pm 2:30 12:20 pm 1:30 12:05 pm 1:75 9:30 am 2:15 11:45 am 1:30 12:10 pm 2:00 1:15 pn 3:55 pn 1:30 1:30 11:45 am 2:00 8:25 an 5:55 pn 11:20 an 9:30 an 7:50 an 7:45 pn 11:20 an 8:15 an 11:55 an 11:10 an 10:15 an 1:55 pm 11:15 pm 10:00 an 12:25 pm 12:40 pm 11:45 an 1:50 pn 11:20 am 3:10 pm 8:20 am 9:00 an 3:10 pm 9:15 am 8:15 am 1:30 1:00 1:30 1:30 3:00 1:30 3:00 2:00 1:30 1:30 1:30 1:30 1:30 1:30 1:30 1:30 1:30 1:30 1:30 1:30 1:30 2:45 1:30 2:15 1:30 Airflow Dissolved Rate Oxygen (mL/min) Concentration (mg/L) 128 128 128 128 128 127 125 128 125 125 125 121 125 121 122 127 124 121 117 117 121 132 128 125 125 124 128 124 121 121 132 138 128 128 124 121 127 125 121 121 138 125 128 122 121 121 122 125 121 121 121 121 124 125 125 122 122 124 117 119 1.90 2.20 1.80 2.00 2.65 3.10 3.15 3.35 3.00 3.55 3.15 3.80 3.70 3.70 4.20 4.50 4.45 5.20 4.45 3.80 2.30 3.30 60 00 15 70 90 10 3.95 85 45 90 50 80 30 35 35 50 75 05 55 30 95 35 4.30 70 50 90 75 40 70 60 00 70 40 15 30 75 85 05 5.20 3.31 1.40 0.88 267 DISSOLVED OXYGEN MEASUREMENTS DISSOLVED OXYGEN MEASUREMENTS DAY DATE 1 Oct/02/90 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 31 Nov/01/90 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 Maximum Mean Minimum Std. Oev. 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 FIXED TIME SampIing REACTOR - Length Time of Time of (Hr:Min> 1:45 pm 8:15 am 2:45 pm 12:20 pm 2:30 pm 2:45 pm 9:30 am 10:00 am 9:15 am 10:00 am 12:35 pm 6:25 pm 2:00 pm 2:40 pm 9:00 am 9:10 am 1:30 pm 2:40 pm 9:55 am 3:30 pm 10:00 am 9:30 am 10:00 am 3:30 pm 4:15 pm 4:40 pm 4:40 pm 10:25 am 4:25 pm 10:50 am 11:35 am 10:55 am 4:45 pm 5:40 pm 11:15 am 12:00 pm 11:35 am 12:00 pm 12:10 pm 12:00 pm 1:10 pm 1:25 pm 1:35 pm 1:55 pm 1:35 pm 2:30 pm 8:55 am 2:40 pra 9:35 am 9:45 am 9:50 am 12:45 pm 1:15 pm 12:30 pm 1:50 pm 3:45 pm 9:45 am 10:20 am 11:00 am 10:05 am AAS0#2 Airflo Rate M Dissolved Oxygen DAY Aeration (mL/min) Concentration (Hr:Min) 1:30 2:15 2:15 1:00 1:30 1:30 2:10 2:30 1:15 1:50 1:30 1:00 2:15 3:00 3:00 3:00 1:00 2:00 3:00 2:15 2:30 1:45 2:00 1:30 2:00 2:00 2:45 2:15 2:00 2:20 2:45 1:50 1:25 2:00 1:30 2:00 1:30 1:30 1:30 1:00 2:00 2:00 2:00 2:00 1:30 2:10 2:30 1:50 2:35 2:30 2:20 2:30 2:50 1:45 2:50 2:15 2:05 2:30 2:45 1:30 37 38 38 45 40 38 35 37 36 35 36 33 30 33 30 28 28 26 30 25 30 30 28 28 25 30 25 25 30 25 20 30 30 33 33 30 26 25 30 30 30 27 30 28 28 30 33 28 25 25 30 30 30 30 28 34 33 30 33 30 <mg/L) 1.90 5.30 1.70 4.70 3.00 3.35 3.60 3.80 3.40 3.30 2.95 3.00 3.15 2.75 3.10 3.00 1.00 1.25 4.40 3.45 3.70 4.00 3.30 2.30 2.60 3.15 3.70 2.75 2.55 2.40 2.00 2.50 2.00 3.50 2.50 0.70 3.10 2.50 3.00 2.15 3.20 3.25 4.30 3.40 2.70 2.20 3.10 2.30 3.40 2.75 3.90 4.25 3.80 4.50 3.70 4.20 4.50 5.10 7.20 7.35 5.30 3.12 0.70 0.93 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 DATE Oct/02/90 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 Nov/01/90 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Maximum Mean Minimum Std. D ev. REAL TIME Sampling Time o (Hr:Min) 1:50 pm 8:15 am 1:35 pm 1:50 pm 2:30 pm 3:25 pm 10:00 am 10:00 am 9:15 am 10:00 am 12:35 pm 4:55 pm 2:45 pm 1:30 pm 9:45 am 10:05 am 1:30 pm 3:55 pm 12:00 pra 3:35 pm 2:40 pra 12:40 pm 10:15 am 2:50 pm 4:15 pm 1:40 pm 5:45 pm 10:20 am 2:15 pm 1:00 pm 3:15 pm 12:15 pm 4:00 pm 4:30 pm 10:20 am 12:55 pm 12:30 pm 12:00 pm 10:25 am 12:00 pm 11:05 am 2:15 pm 11:30 am 1:55 pm 12:25 pm 2:30 pm 10:45 am 4:30 pm 11:30 am 12:15 pm 10:15 am 10:35 pm 9:05 pm 2:35 pm 2:55 pm 3:45 pm 9:35 am 12:15 pm 12:00 pm 10:00 am REACTOR - Length f Time of AAS0#2 Airflow Dissolved Rate Oxygen Aeration (mL/min) Concentration (Hr:Min) 1:30 1:15 0:50 1:00 1:00 1:00 0:50 1:00 1:00 3:00 1:30 1:00 0:45 3:00 1:15 1:00 0:45 2:00 1:00 0:45 2:30 0:50 1:00 0:50 1:00 0:45 0:45 1:00 0:45 1:30 0:50 0:45 1:00 0:50 0:45 1:30 0:45 0:45 0:45 1:00 0:45 1:05 2:30 1:30 0:40 1:50 0:40 0:45 0:50 1:00 1:15 0:45 0:45 1:00 0:45 2:15 0:50 1:30 1:30 3:10 56 43 38 37 40 34 32 33 31 31 32 35 30 30 32 35 31 30 30 28 28 35 33 33 32 36 30 30 30 30 30 25 34 33 30 33 30 30 28 30 30 30 30 28 30 28 35 36 35 34 37 30 27 32 33 37 33 35 35 35 (mg/L) 4.60 4.00 2.75 1.75 4.20 2.80 2.00 2.40 2.75 3.30 1.40 2.25 1.60 1.70 2.20 3.05 1.90 1.90 2.05 1.60 1.50 2.35 2.70 2.30 2.60 3.00 2.50 2.60 2.10 3.00 2.30 1.20 3.40 2.50 2.20 1.00 2.40 2.00 1.60 3.00 2.20 2.30 3.80 2.40 1.20 1.60 1.75 2.55 3.30 3.20 3.75 2.00 1.30 3.10 2.40 3.90 2.60 4.40 6.50 7.10 4.60 2.49 1.00 0.82 268 OAT AAS0#l| DATE 1 Jun/19/90 2 3 4 5 6 7 8 9 10 11 12 20 21 22 23 24 25 26 27 28 29 30 13 Jul/01/90 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 31 Jul/19/90 32 33 34 35 36 37 38 39 40 41 42 43 20 21 22 23 24 25 26 27 28 29 30 31 44 Aug/01/90 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 Maximum Mean Minimum Std. Dev 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 . TEMPERATURE ANO FEED pH 6.86 7.12 7.19 7.05 6.71 6.84 6.84 6.80 7.13 7.30 7.02 6.61 6.78 6.81 6.65 6.94 7.03 6.95 6.77 6.82 6.66 7.03 6.79 7.03 6.89 6.90 6.88 6.99 7.01 6.70 6.77 6.55 6.66 6.70 6.82 6.76 6.88 6.71 6.37 6.41 6.40 6.64 6.62 6.44 6.47 6.46 6.54 6.95 6.65 6.79 6.65 6.68 6.90 6.81 6.69 6.69 6.73 6.72 7.30 6.79 6.37 0.20 FIXED DH MEASUREMENT TIME REACTOR Temp pH •C 20 20 20 24 23 22 22 21 21 21 21 20 22 21 20 19 19 19 20 20 21 21 23 23 22 21 22 20 20 20 -- -- 23 25 22 21 22 21 20 21 23 22 6 6 22 22 22 26 22 24 23 23 24 24 26 24 23 22 21 20 26 21 6 3.3 7.02 7.13 7.12 7.13 6.91 7.04 6.84 6.83 7.07 7.36 7.08 6.61 6.90 6.90 6.66 6.90 6.97 6.94 6.91 6.91 6.80 6.90 6.90 6.90 6.91 6.88 6.86 6.90 6.88 6.82 6.77 6.62 6.55 6.57 6.59 6.60 6.83 6.81 6.89 6.87 6.59 6.59 6.56 6.76 6.70 6.53 6.49 6.53 6.65 6.55 6.65 6.62 6.37 6.44 6.40 6.44 6.42 6.46 6.41 6.47 7.36 6.76 6.37 0.22 REAl TIMI REACTOR Temp pH °C 22 22 22 24 23 22 22 22 22 22 22 22 22 22 22 21 21 20 20 20 21 22 23 24 22 21 22 20 21 20 21 24 24 25 23 22 22 22 20 22 23 23 24 22 22 22 23 26 22 24 24 23 24 24 26 24 23 22 23 22 26 22 20 1.4 7.03 7.13 7.10 7.13 6.87 7.02 6.84 6.86 7.05 7.39 7.00 6.62 6.88 6.90 6.63 6.90 6.96 6.92 6.88 6.89 6.81 6.91 6.89 6.90 6.92 6.88 6.92 6.88 6.90 6.84 6.78 6.69 6.62 6.60 6.62 6.59 6.84 6.86 6.88 6.85 6.59 6.60 6.58 6.74 6.67 6.55 6.51 6.56 6.62 6.54 6.64 6.64 6.42 6.47 6.39 6.41 6.48 6.52 6.44 6.45 7.39 6.77 6.39 0.21 Temp °C 22 22 22 24 23 22 22 22 22 22 22 22 22 22 22 21 21 20 "20 20 21 22 23 24 22 21 22 20 21 20 21 24 24 25 23 22 22 22 20 22 23 23 24 22 22 22 23 26 22 24 24 23 24 24 26 24 23 22 23 22 26 22 20 1.4 S AASD#2 : DAY TEMPERATURE. pH AND )ATE FEED 1 Oct/02/90 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 31 Nov/01/90 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 Maximum Mean Minimum Std. Dev. 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 50 pH 6.83 6.94 6.75 6.65 6.89 6.84 6.72 6.64 6.72 6.81 6.85 6.77 6.93 6.86 7.01 6.89 6.83 6.67 6.83 6.69 6.64 6.57 6.75 6.74 6.68 6.75 6.59 6.79 6.78 6.76 6.76 6.64 6.74 6.80 7.17 7.01 7.05 7.06 7.07 7.12 6.93 7.01 7.02 6.98 7.02 7.15 7.04 7.07 7.05 7.18 6.81 7.21 7.37 7.12 7.27 6.95 6.99 6.96 7.37 6.89 6.57 0.18 Temp Alk °C 20 18 20 18 18 16 15 18 18 18 20 20 15 18 19 18 18 18 14 18 18 15 18 18 20 16 19 17 17 17 16 16 18 18 14 16 18 16 16 15 -- -- 18 16 16 17 18 14 12 15 15 14 16 14 12 15 13 14 13 12 20 17 12 2 204 194 188 150 180 178 165 136 172 164 180 190 208 220 178 162 220 190 166 152 152 128 160 154 150 138 168 164 148 182 186 192 152 170 256 204 248 220 176 200 — ... 180 190 196 208 188 192 184 196 186 190 232 218 220 220 238 166 160 218 256 185 128 28 ALKALINITY MEASUREMENTS FIXED TIME REAL T REACTOR . pH 6.54 6.62 6.60 6.69 6.61 6.65 6.62 6.44 6.43 6.42 6.36 6.41 6.43 6.44 6.40 6.42 6.44 6.46 6.45 6.46 6.46 6.46 6.45 6.45 6.40 6.43 6.42 6.41 6.44 6.45 6.48 6.68 6.55 6.53 6.72 6.54 6.58 6.59 6.65 6.66 6.70 6.65 6.59 6.62 6.65 6.61 6.66 6.63 6.62 6.66 6.63 6.78 6.67 6.68 6.69 6.72 6.71 6.73 6.98 6.98 6.78 6.56 6.36 0.11 Temp Alk °C 20 20 20 20 21 20 20 20 20 20 20 20 20 20 20 20 20 20 19 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 21 20 20 20 20 20 20 19 19 18 20 20 18 18 19 19 18 20 18 21 20 18 1 136 144 166 176 145 155 140 124 124 124 120 134 128 132 142 138 130 128 142 138 140 134 136 128 126 134 124 124 134 138 152 176 154 148 170 144 148 154 154 164 166 166 158 152 158 152 156 156 150 164 152 154 152 160 158 164 164 164 206 226 176 146 120 15 IME REACTOR . pH 6.55 6.44 6.53 6.61 6.50 6.52 6.48 6.45 6.40 6.28 6.38 6.41 6.40 6.46 6.41 6.41 6.45 6.37 6.47 6.46 6.48 6.44 6.46 6.43 6.39 6.73 6.38 6.42 6.40 6.41 6.42 6.88 6.56 6.51 6.65 6.54 6.54 6.56 6.63 6.59 6.64 6.62 6.56 6.61 6.60 6.61 6.63 6.60 6.62 6.61 6.63 6.75 6.62 6.67 6.72 6.69 6.72 6.73 6.94 6.98 6.88 6.54 6.28 0.12 Temp Aik *C 20 20 20 20 21 20 20 20 20 20 20 20 20 20 20 20 20 20 19 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 21 20 20 20 20 20 20 19 19 18 20 20 18 18 19 19 18 20 18 21 20 18 1 140 140 174 166 142 138 140 124 124 110 126 128 130 128 130 136 134 132 138 142 142 134 134 130 128 128 128 128 132 140 142 176 156 148 180 148 148 150 160 158 150 168 144 150 156 164 156 160 152 160 154 158 162 162 158 162 170 166 218 222 180 146 110 15 DAY AASDUM DATE TOTAL COO FEED 1 Jun/19/90 6630 2 3 4 5 6 7 8 9 10 11 12 20 21 22 23 24 25 26 27 28 29 30 6704 3370 7444 7074 5963 10555 7132 7585 9585 9650 9172 13 Jul/01/90 8914 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Maximum Mean Minimum Std. Dev 02 03 04 05 06 .07 08 09 10 11 12 13 14 15 16 17 18 . 12597 13775 10019 18269 18343 19374 14917 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A 19374 10354 3370 4373 MEASUREMENTS Total COD FT RCT 3148 4704 4417 3000 5222 4481 5888 7585 6642 7359 8321 8620 12500 8918 4776 7948 9888 9179 8097 9888 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A 12500 7029 3000 2458 (mg/L) RT RCTR 3963 4280 4481 3074 3000 6333 5815 6113 7699 7397 12044 7628 5365 7518 9234 5037 8029 10949 10402 13029 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A 13029 7070 3000 2826 AASD02 Chemical Oxygen Demand Measurents (mg/L) DATE FEED FT#1 RT#2 Oct/12/90 8176 8257 8457 Nov/9/90 7425 7176 7984 Nov/23/90 8530 6882 6093 APPENDIX F MASS BALANCES - AASD#1 and AASD#2 Chemical Parameter Page AASD#1 - Fixed-Time Reactor TSS 271 VSS 272 Nitrogen 273 Phosphorus 274 - Real-Time Reactor TSS 275 VSS 276 Nitrogen 277 Phosphorus 278 AASD*2 - Fixed-Time Reactor TSS 279 VSS 280 Nitrogen 281 Phosphorus 282 Alkalinity 283 - Real-Time Reactor TSS 284 VSS 285 Nitrogen 286 Phosphorus 287 Alkalinity 288 AASD#1 TOTAL SUSPENDED SOLIDS MASS BALANCE - FIXED-T1HE REACTOR DAY FEED RCTR#1 SUMFEED SUMRCT1 (SUMFD- DELTA RCT SOLIDS X SOLIDS MLSS MLSS Day 1-9 Day 2-10 SUHFT) (Day10-1) RED REDUCED (mg/L) (mg/L) X 0.48 X 0.48 *4.8 ColF-G ColH*100 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 7108 7852 5188 6198 5936 8104 9244 7284 6370 9122 7638 7052 6454 6698 6850 6106 8228 9568 11866 13550 7216 7286 7656 7308 7624 6902 8034 6530 10540 9318 0 0 8070 11872 6514 6858 6618 9594 10068 7818 7818 8014 8042 8072 9430 7964 6940 9736 7642 6114 7814 9264 9592 5950 5464 7696 6482 7936 5726 6848 5716 5598 5790 5524 5436 5336 5376 5924 5866 5712 5938 5826 6100 5854 5826 5852 5878 5970 6278 6724 6980 6818 6774 6752 6666 6702 6568 6530 6604 6960 6980 6800 6856 6956 7416 7172 7006 6954 7028 7370 7472 7322 7084 7140 6792 7052 7252 7088 7456 7216 6904 6826 7082 7278 6960 6756 6628 6516 6646 6270 Moving Average Mass Balance X Removed = Overall Mass Balance X Removed = Day 1-59 224582 30376 31343 31240 32135 32258 32624 32022 30516 30969 32504 33821 36659 36737 37137 37596 37816 38545 37908 37172 34611 33166 34175 30678 27003 31242 38980 38794 38229 38271 37817 38177 41930 45683 41782 34245 34993 36228 36874 35600 35440 35356 34538 34442 35028 35758 34088 32888 33251 31689 31830 31644 Day 2-60 186451 24270 24433 24450 24727 24927 25163 25391 25369 25419 25691 26068 26622 26966 27408 27852 28243 28639 28926 29047 28989 28980 29057 29070 29120 29259 29602 29892 30120 30288 30321 30508 30830 31054 31116 30983 30801 30823 30966 30995 31036 30913 30712 30588 30561 30794 30750 30512 30291 29840 29566 29262 FD-FT 38131 6107 6910 6790 7408 7331 7461 6631 5147 5550 6813 7753 10037 9771 9729 9744 9573 9906 8983 8125 5622 4187 5118 1608 -2117 1983 9378 8902 8109 7983 7497 7669 11100 14628 10667 3262 4192 5405 5908 4605 4404 4443 3826 3853 4468 4964 3338 2376 2960 1849 2264 2382 Day 60-1 2659 -19 1632 173 2765 2006 2352 2285 -221 499 2717 3773 5539 3446 4416 4445 3907 3955 2870 1210 -576 -96 778 125 499 1392 3427 2899 2285 1680 326 1872 3226 2237 614 -1325 -1824 221 1430 288 413 -1229 -2006 -1238 -278 2333 -442 -2381 -2208 -4512 -2736 -3043 Solids Reduced 35472 6126 5278 6617 4644 5324 5109 4346 5367 5051 4096 3980 4498 6324 5313 5299 5666 5951 6112 6916 6198 4283 4340 1483 -2616 591 5951 6003 5824 6303 7170 5797 7874 12392 10052 4587 6016 5184 4477 4317 3992 5672 5832 5092 4746 2631 3780 4757 5168 6361 5000 5425 ColD 14.70 15.79 20.2 16.8 21.2 14.5 16.5 15.7 13.6 17.6 16.3 12.6 11.8 12.3 17.2 14.3 14.1 15.0 15.4 16.1 18.6 17.9 12.9 12.7 4.8 -9.7 1.9 15.3 15.5 15.2 16.5 19.0 15.2 18.8 27.1 24.1 13.4 17.2 14.3 12.1 12.1 11.3 16.0 16.9 14.8 13.5 7.4 11.1 14.5 15.5 20.1 15.7 17.1 272 AASD#1 VOLATILE SUSPENDED SOLIDS MASS BALANCE - FIXED-TIME REACTOR DAY FEED RCTR#1 SUHFEED SUHRCT1 (SUMFD- DELTA RCT SOLIDS X SOLIDS MLVSS MLVSS Day 1-9 Day 2-10 SUHFT) <Day10-1) RED REDUCED (mg/L) (mg/L) X 0.48 X 0.48 *4.8 ColF-G ColH*100 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 5716 6308 4158 4982 4740 6438 7318 5772 5104 7214 6056 5550 5084 5186 5366 4798 6442 7516 9486 10794 5736 5772 6144 5756 6078 5472 6342 5170 8308 7396 0 0 6386 9568 5228 5462 5230 7602 7864 6114 6168 6288 6328 6372 7344 6214 5384 7608 5912 4728 6008 7168 7512 4556 4202 5910 4944 6114 4400 5256 4496 4412 4552 4358 Moving Average Mass Balance X Removed = Overall Mass Balance % Removed = 4252 Day 1-59 Day 2-60 4154 4216 4728 4632 4454 4606 4510 4704 4506 4490 4508 4522 4602 4864 5204 5416 5298 5272 5236 5192 5202 5088 5046 5084 5400 5388 5240 5284 5370 5718 5428 5406 5380 5424 5702 5812 5692 5468 5498 5228 5452 5566 5418 5732 5538 5274 5266 5456 5584 5330 5152 5058 4994 5090 4818 177010 24257 24976 24855 25524 25572 25787 25272 24062 24384 25542 26632 28907 28996 29326 29786 29973 30588 30122 29558 27487 26293 27090 24320 21371 24738 31006 30889 30467 30495 30156 30381 33316 36276 33164 27016 27565 28469 28941 27876 27754 27657 26965 26831 27234 27781 26443 25477 25730 24451 24548 24391 144132 19084 19177 19157 19323 19445 19606 19746 19647 19633 19830 20117 20552 20837 21204 21563 21891 22217 22451 22538 22480 22473 22516 22500 22524 22609 22857 23020 23193 23335 23346 23497 23772 23967 24014 23909 23813 23835 23924 23921 23936 23804 23604 23507 23486 23657 23599 23400 23227 22873 22658 22439 FD-FT 32878 5173 5799 5699 6201 6128 6180 5526 4415 4751 5712 6516 8355 8159 8122 8223 8082 8370 7671 7020 5006 3821 4574 1819 -1153 2129 8149 7869 7274 7161 6810 6884 9544 12309 9150 3108 3753 4634 5017 3955 3818 3852 3362 3324 3748 4124 2844 2077 2503 1578 1890 1952 Day 60-1 1546 -202 931 -202 1661 1219 1613 1402 -989 -144 1968 2870 4349 2851 3677 3581 3283 3264 2333 874 -576 -77 432 -154 230 854 2477 1632 1728 1421 115 1507 2746 1958 470 -1056 -960 221 893 -29 144 -1315 -2006 -970 -202 1709 -586 -1987 -1728 -3542 -2150 -2189 Solids Reduced 31332 5375 4868 5900 4540 4908 4568 4124 5404 4895 3744 3645 4006 5308 4445 4643 4799 5106 5339 6147 5582 3898 4142 1973 -1383 1275 5673 6237 5546 5740 6695 5377 6799 10351 8679 4164 4713 4413 4124 3984 3674 5168 5368 4294 3949 2415 3430 4065 4231 5121 4041 4140 ColD 16.79 17.70 22.2 19.5 23.7 17.8 19.2 17.7 16.3 22.5 20.1 14.7 13.7 13.9 18.3 15.2 15.6 16.0 16.7 17.7 20.8 20.3 14.8 15.3 8.1 -6.5 5.2 18.3 20.2 18.2 18.8 22.2 17.7 20.4 28.5 26.2 15.4 17.1 15.5 14.3 14.3 13.2 18.7 19.9 16.0 14.5 8.7 13.0 16.0 16.4 20.9 16.5 17.0 273 AASD41 NITROGEN MASS BALANCE - FI DAY FEED RCTR#1 (TKN + (TKN + NOx) NOx) (mg/L) (mg/L) 1 478.45 346.72 2 510.75 395.15 3 334.05 378.19 4 445.53 366.92 SUMFEED Day 1-9 N In X 0.48 SUMRCT1 Day 2-10 N Out X 0.48 CSUMFD- SUMFT) XED-TIME DELTA-N RCTR#1 (Day10-1) X 4.8 REACTOR Nitrogen Lost ColF-G Moving Average Mass Balance X Removed = Overall Mass Balance X Removed = 5 410.45 389.77 Day 1-59 Day 2-60 6 552.71 265.08 7 599.72 358.94 8 486.17 384.60 9 409.54 362.22 10 674.61 386.11 11 541.78 397.09 12 515.24 400.51 13 453.94 413.52 14 439.24 378.39 15 465.84 375.20 16 445.26 410.81 17 535.46 407.72 18 630.32 403.69 19 807.79 411.31 20 953.35 448.22 21 513.17 478.27 22 525.70 487.54 23 529.29 467.02 24 559.91 455.09 25 570.51 483.14 26 527.58 466.05 27 571.85 459.30 28 497.38 465.57 29 713.93 430.92 30 616.13 459.05 31 0.00 453.21 32 0.00 476.15 33 541.24 448.93 34 770.23 454.15 35 441.39 482.96 36 442.50 472.40 37 432.55 465.65 38 617.39 458.24 39 684.93 475.05 40 498.58 474.83 41 549.81 483.14 42 547.57 476.67 43 584.22 478.97 44 589.22 472.82 45 657.31 476.35 46 587.52 474.15 47 494.84 465.26 48 691.52 347.13 49 539.23 494.68 50 446.95 451.55 51 560.54 455.71 52 691.56 463.83 53 707.20 496.66 54 435.02 494.19 55 407.48 476.20 56 586.68 460.11 57 464.32 459.61 58 600.21 444.75 59 410.68 450.32 60 483.56 434.72 15652 2029 2123 2138 2225 2229 2243 2201 2127 2151 2257 2321 2518 2517 2552 2595 2640 2700 2696 2668 2519 2404 2454 2202 1947 2198 2664 2623 2560 2529 2483 2516 2755 3019 2762 2303 2374 2478 2552 2493 2496 2516 2466 2473 2524 2581 2474 2388 2432 2323 2352 2335 12434 1578 1579 1589 1612 1606 1659 1684 1695 1715 1727 1752 1789 1825 1867 1905 1940 1968 1995 2021 2013 2003 1987 1991 1988 1974 1983 1989 1989 2002 2010 2020 2023 2037 2049 2044 2046 2050 2053 1992 2001 1986 1976 1969 1980 1989 1990 1987 2041 2017 2017 2007 FD-FT 3218 451 545 549 613 623 584 517 432 436 530 569 729 693 685 690 700 732 702 647 507 401 467 210 -41 224 681 634 572 527 473 496 732 983 714 260 329 428 499 501 495 530 490 504 544 592 484 400 391 305 335 328 Day 60-1 422 189 9 107 224 -55 529 249 111 199 121 245 373 355 425 383 347 280 267 260 -83 -92 -165 44 -30 -139 81 63 0 131 77 104 34 133 119 -49 19 41 34 -614 95 -152 -101 -73 114 86 10 -25 540 -240 -6 -101 Nitrogei Removed 2796 262 535 442 390 678 55 268 321 237 409 324 356 337 259 306 353 452 435 387 590 493 632 166 -11 363 600 571 571 396 397 392 698 849 595 308 310 387 465 1115 400 681 591 577 430 506 475 425 -149 545 341 429 X N Lost :olH*100 ColD 17.47 17.86 l 12.9 25.2 20.7 17.5 30.4 2.5 12.2 15.1 11.0 18.1 13.9 14.1 13.4 10.2 11.8 13.4 16.7 16.1 14.5 23.4 20.5 25.7 7.6 -0.6 16.5 22.5 21.8 22.3 15.7 16.0 15.6 25.3 28.1 21.5 13.4 13.0 15.6 18.2 44.7 16.0 27.1 24.0 23.3 17.0 19.6 19.2 17.8 -6.1 23.5 14.5 18.4 274 DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 AASD#1 FEED TP Cmg/L) 220 241 164 214 205 271 307 250 216 352 294 279 259 246 259 246 308 354 410 472 252 262 261 276 292 263 301 246 413 366 0 0 325 445 261 271 279 385 429 330 345 320 340 344 399 361 301 332 332 276 347 415 323 265 250 364 294 375 253 295 PHOSPHORUS RCTR#1 TP (mg/L) 186 218 211 210 SUHFEED Day 1-9 X 0.48 MASS BALANCE - F SUMRCT1 Day 2-10 X 0.48 CSUMFD- SUMFT) IXED-TIME DELTA RCT (Day10-1) *4.8 REACTOR TOTAL P Lost X P Lost :olF-G ColH*100 lovinq Average Mass Balance X Removed = Overall Mass Balance X Removed = 226 Day 1-59 Day 2-60 164 216 234 230 261 265 259 277 260 258 263 269 270 259 277 297 292 292 286 309 287 289 292 311 341 326 354 346 342 385 344 344 334 343 353 358 321 325 329 329 333 323 328 347 328 329 332 348 359 355 339 344 332 346 338 8750 1002 1066 1091 1146 1168 1188 1182 1152 1180 1247 1274 1360 1347 1348 1356 1364 1386 1364 1339 1260 1232 1286 1161 1035 1215 1502 1501 1487 1502 1489 1519 1678 1843 1685 1421 1461 1522 1561 1521 1475 1476 1442 1455 1491 1481 1417 1364 1394 1376 1396 1385 8562 946 968 991 1023 1040 1085 1107 1124 1143 1142 1148 1166 1174 1189 1202 1224 1233 1242 1258 1274 1296 1312 1342 1370 1386 1433 1460 1485 1496 1497 1510 1512 1500 1491 1464 1457 1452 1447 1440 1437 1422 1426 1429 1439 1453 1464 1471 1479 1472 1480 1485 F0-FT 189 57 97 100 123 128 103 74 28 37 104 126 193 173 159 153 139 153 122 81 -14 -64 -25 -181 -335 -171 69 41 2 7 -8 10 166 344 193 -44 3 70 115 82 38 53 16 26 53 28 -47 -108 -85 -96 -84 -99 Day 60-1 730 360 226 230 322 163 451 226 168 192 -10 58 182 72 154 134 221 86 91 158 163 211 163 298 288 158 470 264 250 110 10 130 19 -120 -82 -269 -72 -53 -53 -72 -29 -144 38 34 91 144 106 77 77 -71 86 43 Phosphor Reduced -541 -303 -128 -131 -199 -35 -348 -151 -140 -155 114 69 11 101 6 19 -82 66 31 -78 -178 -275 -189 -479 -623 -330 -402 -223 -248 -104 -17 -120 147 464 275 225 75 123 168 154 67 197 -22 -8 -38 -116 -152 -184 -162 -24 -170 -143 ColD -6.48 -6.18 us -30.3 -12.0 -12.0 -17.3 -3.0 -29.3 -12.8 -12.1 -13.1 9.1 5.4 0.8 7.5 0.4 1.4 -6.0 4.8 2.3 -5.8 -14.1 -22.3 -14.7 -41.2 -60.2 -27.1 -26.7 -14.8 -16.7 -6.9 -1.2 -7.9 8.8 25.2 16.3 15.8 5.2 8.1 10.7 10.1 4.5 13.4 -1.5 -0.5 -2.6 -7.8 -10.7 -13.5 -11.6 -1.7 -12.2 -10.3 AASD#1 TOTAL SUSPENDED SOLIDS MASS BALANCE - REAL-TIME REACTOR 275 DAY FEED RCTR#2 SUMFEED SUMRCT2 (SUMFD- DELTA RCT SOLIDS X SOLIDS MLSS MLSS Day 1-9 Da/ 2-10 SUMRT) (Day10-1) RED REDUCED (mg/L) (mg/L) X 0.48 X 0.48 *4.8 ColF-G ColH*100 ColD 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 7108 7852 5188 6198 5936 8104 9244 7284 6370 9122 7638 7052 6454 6698 6850 6106 8228 9568 11866 13550 7216 7286 7656 7308 7624 6902 8034 6530 10540 9318 0 0 8070 11872 6514 6858 6618 9594 10068 7818 7818 8014 8042 8072 9430 7964 6940 9736 7642 6114 7814 9264 9592 5950 5464 7696 6482 7936 5726 6848 5640 5574 5678 5470 Moving Average Mass Balance X Removed = Overall Mass Balance X Removed = 5308 Day 1-59 5288 5370 5756 5736 5540 5700 6060 6054 5658 6028 5854 5674 5658 6122 6680 7054 6900 6810 6664 6740 6554 6448 6378 6528 6849 7040 6748 6930 6682 7200 7138 6828 6776 6974 7404 7328 7274 6896 7186 6862 7182 7010 6992 7218 6856 6984 6964 7106 7274 6852 6666 6774 6482 6706 6562 224582 30376 31343 31240 32135 32258 32624 32022 30516 30969 32504 33821 36659 36737 37137 37596 37816 38545 37908 37172 34611 33166 34175 30678 27003 31242 38980 38794 38229 38271 37817 38177 41930 45683 41782 34245 34993 36228 36874 35600 35440 35356 34538 34442 35028 35758 34088 32888 33251 31689 31830 31644 Day 2-60 184813 23866 23926 24109 24390 24558 24913 25145 25106 25068 25348 25818 26295 26701 27254 27560 27985 28407 28787 28909 28836 28738 28805 28776 28903 28875 29185 29517 29733 29852 29912 30086 30365 30530 30633 30626 30493 30663 30776 30784 30695 30468 30329 30362 30324 30521 30363 30198 30093 29740 29668 29465 FD-FT 39769 6511 7417 7131 7745 7700 7711 6876 5410 5900 7156 8003 10363 10036 9882 10037 9831 10138 9122 8263 5774 4428 5370 1902 -1900 2367 9794 9277 8496 8420 7906 8091 11565 15153 11149 3619 4500 5564 6098 4815 4745 4887 4209 4080 4705 5237 3725 2690 3157 1949 2162 2178 Day 60-1 4426 -480 605 1834 2803 1680 3552 2323 -394 -374 2794 4704 4771 4061 5530 3053 4253 4224 3792 1229 -730 -984 672 -298 1277 -278 3101 3312 2160 1190 600 1747 2784 1651 1027 -67 -1325 1699 1123 86 -893 -2266 -1392 326 -384 1978 -1584 -1651 -1046 -3533 -720 -2026 Solids Reduced 35344 6991 6812 5297 4942 6020 4159 4553 5803 6275 4362 3299 5592 5975 4353 6984 5579 5914 5330 7034 6504 5412 4698 2200 -3177 2645 6694 5965 6336 7229 7306 6344 8781 13501 10122 3686 5824 3865 4975 4729 5638 7153 5601 3754 5089 3259 5309 4341 4204 5482 2882 4204 15.18 15.74 23.0 21.7 17.0 15.4 18.7 12.7 14.2 19.0 20.3 13.4 9.8 15.3 16.3 11.7 18.6 14.8 15.3 14.1 18.9 18.8 16.3 13.7 7.2 -11.8 8.5 17.2 15.4 16.6 18.9 19.3 16.6 20.9 29.6 24.2 10.8 16.6 10.7 13.5 13.3 15.9 20.2 16.2 10.9 14.5 9.1 15.6 13.2 12.6 17.3 9.1 13.3 276 AASD#1 VOLATILE SUSPENDED SOLIDS MASS BALANCE - REAL-TIME REACTOR DAY FEED RCTR#2 SUMFEED SUHRCT2 (SUHFD- DELTA RCT SOLIDS X SOLIDS MLVSS HLVSS Day 1-9 Day 2-10 SUMRT) (Day10-1) RED REDUCED <mg/L) <mg/L) X 0.48 X 0.48 *4.8 ColF-G CotH*100 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 5716 6308 4158 4982 4740 6438 7318 5772 5104 7214 6056 5550 5084 5186 5366 4798 6442 7516 9486 10794 5736 5772 6144 5756 6078 5472 6342 5170 8308 7396 0 0 6386 9568 5228 5462 5230 7602 7864 6114 6168 6288 6328 6372 7344 6214 5384 7608 5912 4728 6008 7168 7512 4556 4202 5910 4944 6114 4400 5256 4430 4386 4460 4304 4148 4116 4390 4526 4528 4328 4410 4694 4664 4346 4645 4498 4370 4356 4740 5168 5436 5344 5256 5152 5240 5020 4970 4848 5026 5288 5420 5178 5308 5124 5500 5478 5232 5196 5340 5712 5640 5612 5290 5502 5254 5498 5320 5306 5498 5200 5326 5282 5388 5560 5170 4984 5064 4870 5008 4956 Moving Average Mass Balance X Removed - Overall Mass Balance X Removed = Day 1-59 177010 24257 24976 24855 25524 25572 25787 25272 24062 24384 25542 26632 28907 28996 29326 29786 29973 30588 30122 29558 27487 26293 27090 24320 21371 24738 31006 30889 30467 30495 30156 30381 33316 36276 33164 27016 27565 28469 28941 27876 27754 27657 26965 26831 27234 27781 26443 25477 25730 24451 24548 24391 Day 2-60 142019 18809 18821 18933 19106 19201 19455 19507 19432 19349 19547 19911 20267 20593 21030 21274 21630 21942 22236 22288 22220 22149 22186 22148 22223 22167 22398 22642 22826 22908 22932 23073 23294 23440 23520 23521 23413 23541 23601 23584 23482 23270 23133 23129 23075 23221 23064 22903 22787 22485 22393 22215 FD-RT 34991 5448 6156 5922 6418 6372 6332 5765 4631 5035 5995 6721 8640 8402 8296 8512 8343 8646 7885 7270 5267 4144 4905 2172 -852 2571 8608 8247 7641 7588 7224 7308 10021 12836 9644 3495 4152 4928 5340 4292 4272 4386 3832 3702 4160 4560 3379 2575 2943 1966 2155 2175 Day 60-1 2525 -490 115 1123 1728 950 2539 518 -749 -826 1978 3638 3562 3264 4368 2434 3562 3120 2947 518 -682 -710 365 -374 749 -557 2304 2438 1843 816 250 1402 2218 1459 797 10 -1075 1277 595 -163 -1027 -2112 -1373 -38 -547 1469 -1574 -1613 -1162 -3014 -922 -1776 Solids Reduced 32466 5938 6040 4799 4690 5421 3792 5247 5379 5860 4017 3083 5078 5138 3928 6079 4782 5526 4938 6752 5948 4855 4540 2546 -1601 3128 6304 5809 5797 6772 6974 5907 7804 11377 8847 3486 5227 3651 4745 4455 5299 6498 5205 3740 4707 3091 4954 4188 4105 4980 3077 3951 ColD 17.99 18.34 24.5 24.2 19.3 18.4 21.2 14.7 20.8 22.4 24.0 15.7 11.6 17.6 17.7 13.4 20.4 16.0 18.1 16.4 22.8 21.6 18.5 16.8 10.5 -7.5 12.6 20.3 18.8 19.0 22.2 23.1 19.4 23.4 31.4 26.7 12.9 19.0 12.8 16.4 16.0 19.1 23.5 19.3 13.9 17.3 11.1 18.7 16.4 16.0 20.4 12.5 16.2 AASD#1 . NITROGEN MASS BALANCE - RE DAY FEED RCTR#2 (TKN + (TKN + NOx) NOx) (mg/L) (mg/L) 1 478.45 360.74 SUHFEED Day 1-9 N In X 0.48 SUMRCT2 Day 2-10 N Out X 0.48 CSUMFD- SUMRT) AL-TIME REACTOR DELTA-N Nitroger RCTR#2 (Day10-1) X 4.8 Lost ColF-G 2 510.75 368.83 Moving Average Mass Balance X Removed = 3 334.05 402.55 4 445.53 323.14 5 410.45 352.74 6 552.71 348.22 7 599.72 352.27 8 486.17 369.80 9 409.54 360.00 10 674.61 404.11 11 541.78 403.88 12 515.24 389.38 13 453.94 404.78 14 439.24 415.12 15 465.84 415.85 16 445.26 378.03 17 535.46 348.59 18 630.32 341.65 19 807.79 396.03 20 953.35 430.38 21 513.17 467.50 22 525.70 439.50 23 529.29 474.50 24 559.91 461.74 25 570.51 441.68 26 527.58 425.45 27 571.85 452.78 28 497.38 426.30 29 713.93 409.43 30 616.13 440.15 31 0.00 451.59 32 0.00 489.76 33 541.24 448.22 34 770.23 446.12 35 441.39 478.17 36 442.50 478.18 37 432.55 423.81 38 617.39 457.17 39 684.93 472.77 40 498.58 502.18 41 549.81 493.03 42 547.57 464.01 43 534.22 436.00 44 589.22 452.12 45 657.31 465.59 46 587.52 473.04 47 494.84 484.60 48 691.52 476.98 49 539.23 466.34 50 446.95 474.22 51 560.54 432.39 52 691.56 451.31 53 707.20 443.20 54 435.02 497.54 55 407.48 450.36 56 586.68 451.32 57 464.32 433.75 58 600.21 449.91 59 410.68 434.55 60 483.56 392.90 Overall Mass Balance X Removed - Day 1-59 15652 2029 2123 2138 2225 2229 2243 2201 2127 2151 2257 2321 2518 2517 2552 2595 2640 2700 2696 2668 2519 2404 2454 2202 1947 2198 2664 2623 2560 2529 2483 2516 2755 3019 2762 2303 2374 2478 2552 2493 2496 2516 2466 2473 2524 2581 2474 2388 2432 2323 2352 2335 Day 2-60 12199 1575 1592 1586 1625 1655 1687 1700 1689 1681 1677 1690 1727 1744 1772 1794 1825 1862 1915 1930 1919 1906 1912 1919 1913 1915 1940 1953 1951 1974 1990 2014 2016 2023 2019 2006 2000 2024 2037 2039 2022 2013 1997 2005 2000 2016 2005 1989 1968 1960 1941 1922 FD-RT 3452 454 531 552 600 574 556 502 438 470 580 631 791 774 780 801 815 839 781 739 600 498 542 282 35 283 723 670 609 555 493 502 740 996 744 297 374 454 515 454 475 503 469 468 524 565 469 399 464 362 411 412 Day 60-1 154 208 168 -63 392 299 325 124 -102 -88 -39 127 375 167 285 220 306 369 533 145 -101 -131 58 73 -65 21 253 122 -12 229 157 243 16 76 -49 -125 -60 236 132 20 -172 -90 -152 73 -43 153 -109 -160 -208 -79 -190 -190 Nitroge Removec 3298 246 363 616 208 275 231 378 540 558 619 504 416 607 495 580 510 470 248 594 700 629 484 209 99 262 470 548 621 326 336 259 724 920 793 422 435 218 383 434 647 593 621 394 567 412 578 558 671 441 601 602 X N Lost ColH*10( ColD 19.51 21.07 « 12.1 17.1 28.8 9.4 12.3 10.3 17.2 25.4 26.0 27.4 21.7 16.5 24.1 19.4 22.4 19.3 17.4 9.2 22.2 27.8 26.2 19.7 9.5 5.1 11.9 17.7 20.9 24.3 12.9 13.5 10.3 26.3 30.5 28.7 18.3 18.3 8.8 15.0 17.4 25.9 23.6 25.2 16.0 22.4 15.9 23.4 23.4 27.6 19.0 25.6 25.8 AASD#1 PHOSPHORUS MASS BALANCE • REAL-TIME REACTOR DAY FEED RCTR#2 SUMFEED SUMRCT2 (SUMFD- DELTA RCT TOTAL X P TP TP Day 1-9 Day 2-10 SUMRT) (Day10-1) P Lost Lost (mg/L) (mg/L) X 0.48 X 0.48 *4.8 ColF-G ColH*100 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 220 241 164 214 205 271 307 250 216 352 294 279 259 246 259 246 308 354 410 472 252 262 261 276 292 263 301 246 413 366 0 0 325 445 261 271 279 385 429 330 345 320 340 344 399 361 301 332 332 276 347 415 323 265 250 364 294 375 253 295 199 205 225 199 Moving Average Mass Balance X Removed = Overall Mass Balance X Removed = 216 Day 1-59 Day 2-60 215 219 231 230 256 251 247 264 254 258 275 255 252 254 265 289 279 298 293 280 274 288 271 326 341 346 370 373 359 369 361 331 351 350 376 385 320 309 320 334 338 338 351 341 350 328 343 333 364 349 349 363 361 348 333 8750 1002 1066 1091 1146 1168 1188 1182 1152 1180 1247 1274 1360 1347 1348 1356 1364 1386 1364 1339 1260 1232 1286 1161 1035 1215 1502 1501 1487 1502 1489 1519 1678 1843 1685 1421 1461 1522 1561 1521 1475 1476 1442 1455 1491 1481 1417 1364 1394 1376 1396 1385 8617 958 980 991 1022 1040 1061 1088 1099 1110 1109 1116 1136 1143 1164 1181 1183 1192 1210 1218 1247 1272 1304 1339 1377 1415 1461 1496 1524 1536 1541 1555 1562 1537 1513 1489 1476 1480 1474 1474 1457 1440 1444 1461 1467 1481 1487 1492 1498 1507 1506 1509 FD-RT 133 44 85 100 124 128 127 94 53 71 138 159 224 204 184 175 180 193 155 121 13 -40 -18 -178 -342 -200 41 5 -38 -34 -52 -36 115 306 172 -69 -16 42 88 47 17 35 -2 -5 24 0 -70 -128 -104 -132 -110 -123 Day 60-1 643 274 221 106 312 182 206 269 115 106 -10 67 202 72 211 168 24 91 173 82 293 250 322 346 384 379 456 350 288 120 43 144 72 -254 -240 -235 -130 34 -62 5 -168 -168 38 163 62 144 53 53 58 96 -10 24 Phosphor Reduced -510 -229 -135 -5 -188 -55 -80 -175 -62 -35 147 92 23 132 -27 7 156 102 -18 39 -280 -290 -339 -524 -726 -579 -415 -345 -326 -154 -95 -180 43 561 412 167 114 9 150 42 185 203 -40 -168 -38 -144 -122 -181 -161 -228 -100 -147 ColD -6.90 -5.83 us -22.9 -12.7 -0.5 -16.4 -4.7 -6.7 -14.8 -5.4 -3.0 11.8 7.2 1.7 9.8 -2.0 0.5 11.5 7.4 -1.3 2.9 -22.2 -23.5 -26.4 -45.1 -70.1 -47.7 -27.6 -23.0 -21.9 -10.3 -6.4 -11.8 2.6 30.4 24.4 11.7 7.8 0.6 9.6 2.8 12.6 13.8 -2.8 -11.6 -2.5 -9.7 -8.6 -13.3 -11.6 -16.5 -7.2 -10.6 2fc - 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S O S o . N i ^ i n o i o S . a S ^ - o . N ' i i n ^ v f M r y l N K i n M K I M M n i M K I K I I M I M I M n W N O I N I M I « - ( M N I M ( M N I M ^ t - t - ( M « - ^ » - r - » - i - r- T- r*. ** m *o «— N* — ~ —. - O S . N N o t̂  in to in in in in CM IM CM CM >minr\ir--inr^»tN-coeo»»fOCMO «MC0IMC0«*O>*IM^"*-*rMO«M tor^t>->Oin^(M>t^^incoN-o to -O r- vj in to to CM CM to <0 to -t in , .. . _ sQ *o *Q »o >o *o Ô *0 *o *0 *0 *0 ^ *0 *0 *0 *o *0 *o eo co *0 "4" - O ^ M O IM CM O O m i n u i m a 0 ' O O v g < N t a D ~ » M ) 0 - J - } I M O O - * - l ' O M > O M N N < t ^ - O O M r j O ' O N M O M ( M O M O < f O O O O - 0 - 0 - g T - o - j o e O i - S i n i n t - N i n ' O a o N n f M ' O M O O ' - S ' - i S o - j n i n M C O N ' O - i c o ^ ' O S N f^ to «- m <o * O i n o ( M o o o ^ r o ( M o e o i n * - M ^ > o c o O ' 4 f y r J i n i n t - i n s r N > 0 ' i o O f - i n » - v j o S i O T - o eg <o o CM o o r > ^ i n i n i n , 0 N o r > « 0 K ( > i n < 0 s t t 0 S i n « K ^ N ' 0 4 i n N N i n t 0 < c 3 > 0 i n > 0 S > 0 , 0 « ) / i i n -o so *o •o «0 »— «— C M o e o - * e o i M c \ j > * - o o v * o c o f ~ t o « - i n c o f ~ o o » o t o t o c o c M t o > o * - o « - S - O O C M O - * o - » > 0 - » < g o i n « * m N . r O « -> o , o > o , o i n < o i n i n i n > o , O i n i A i A ^ ^ t O ' - c u M > » i n ' O K » c > o » - f \ i ) < i > » i n ' O N o o c > O i - N i < i > » i n ^ N « ) 0 ' O r - t \ i M - * i n < O N « 0 0 > 0 ' - r \ i n - » i n < o S « ) c » O t - f > i K i . » i n ^ N e o O ' 0 > - > - < - < - » - > - < - ' - r - T - w N M r i i M N r v i r j N r \ i n m i n i O M i o i O M i O K i ^ > » > * - * ~ t > » - » - * - * - * i n i n i n i n i n i n i / n n i n i n > o 280 AASD#2 VOLATILE SUSPENDED SOLIDS MASS BALANCE - FIXED-TIME REACTOR Note: Mass Balance has used 58 days of data. DAY FEED RCTR#1 SUMFEED SUMRCT1 (SUHFD- DELTA RCT SOLIDS X SOLIDS MLVSS MLVSS Day1-19 Day 2-20 SUMFT) (Day20-1) RED REDUCED (mg/L) (mg/L) X 0.24 X 0.24 *4.8 ColF-G ColH*100 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 8466 7818 3362 4922 4438 4832 4958 6092 8442 7510 4984 6476 7898 4326 5282 4120 7150 6462 4902 5286 6028 5212 6176 5436 5016 4540 6038 5874 4590 6948 5578 5154 4560 5060 6160 5828 5650 5664 4278 4928 0 0 5630 5434 4918 5130 4972 4446 4880 4500 4570 4438 5434 4920 4480 4402 4554 3930 3606 5148 5032 5316 5350 5148 5204 5032 Moving Average Mass > Balance X Removed = Overall Mass Balance X Removed = 4966 Day 1-57 Day 2-58 (FD-FT) Day 58-1 4912 4930 5060 5268 5096 5162 5176 5092 5132 4934 4830 4978 4952 4956 4982 5018 4954 4906 4988 4784 4852 4850 4846 4802 4910 4772 4722 4676 4802 4760 4864 4850 4716 4762 4764 4680 4834 4796 4664 4682 4562 4581 4624 4612 4492 4238 4266 4284 4122 4146 4208 4074 4042 74452 26986 26222 25793 26237 26538 26777 26821 26721 26708 26092 25391 25862 25647 24988 25044 24991 25481 25164 24969 25152 24910 24646 23395 21912 23310 24715 24805 24588 24371 24336 23840 23581 23441 23412 23502 23204 22881 22581 22315 22231 21914 65968 23169 23083 22994 22963 22903 22873 22878 22848 22829 22778 22677 22607 22546 22449 22360 22251 22219 22202 22175 22151 22093 22040 21979 21913 21896 21850 21821 21780 21711 21648 21605 21534 21466 21350 21252 21127 20974 20802 20648 20494 20321 8484 3816 3140 2798 3274 3635 3904 3943 3874 3879 3313 2714 3256 3101 2539 2684 2740 3262 2961 2794 3001 2817 2605 1416 -1 1414 2865 2984 2807 2660 2689 2235 2048 1975 2062 2250 2077 1906 1779 1667 1737 1593 -3955 -384 -1728 -1766 -624 -1200 -605 106 -614 -374 -1008 -2026 -1411 -1210 -1939 -1776 -2189 -634 -336 -547 -490 -1152 -1056 -1219 -1315 -346 -922 -576 -816 -1382 -1272 -854 -1430 -1344 -2323 -1968 -2486 -3062 -3446 -3082 -3082 -3456 Solids Reduced 12439 4200 4868 4565 3898 4835 4509 3838 4488 4254 4321 4740 4667 4310 4478 4460 4929 3895 3297 3341 3491 3969 3661 2635 1314 1760 3786 3560 3623 4042 3961 3090 3478 3319 4385 4218 4563 4969 5226 4748 4819 5049 ColD 16.08 16.71 15.6 18.6 17.7 14.9 18.2 16.8 14.3 16.8 15.9 16.6 18.7 18.0 16.8 17.9 17.8 19.7 15.3 13.1 13.4 13.9 15.9 14.9 11.3 6.0 7.5 15.3 14.4 14.7 16.6 16.3 13.0 14.8 14.2 18.7 17.9 19.7 21.7 23.1 21.3 21.7 23.0 281 AASD#2 Not NITROGEN MASS BALANCE e: M DAY FEED RCTR#1 (NOx + (TKN + NOx) NOX) Cmg/L) (mg/L) 1 652.90 510.83 2 735.48 503.15 3 536.08 523.23 4 437.18 529.10 5 401.10 513.20 6 395.92 487.96 7 438.49 482.18 8 294.20 487.66 9 647.48 461.16 10 713.72 480.82 11 464.09 455.41 12 563.69 448.40 13 688.07 470.66 14 397.14 451.10 15 475.21 496.71 16 355.23 452.85 17 616.35 445.78 18 552.07 468.38 19 408.69 466.24 20 446.18 454.36 21 511.16 438.93 22 426.18 446.17 23 554.24 455.38 24 508.10 462.14 25 453.41 461.04 26 414.25 445.51 27 559.24 444.69 28 520.34 429.60 29 423.16 448.20 30 631.57 447.13 31 533.57 435.61 32 472.31 457.62 33 423.23 452.27 34 450.30 422.66 35 556.24 440.09 36 513.26 450.05 37 510.30 452.84 38 486.30 437.70 39 400.74 425.89 40 457.39 438.17 41 0.00 430.19 42 0.00 403.25 43 517.22 407.05 44 510.36 433.15 45 453.57 402.70 46 465.25 408.36 47 470.04 399.45 48 422.56 410.46 49 456.62 410.70 50 402.42 411.99 51 436.65 403.09 52 408.88 401.48 53 509.15 392.33 54 475.21 367.24 55 436.35 387.64 56 422.65 377.67 57 429.37 353.75 58 333.27 376.23 59 316.31 361.19 60 429. 21 372. 28 ass Balance has use SUMFEED - FIXED-TIME REACTOR d 58 days of data. SUMRCT1 CSUMFD- Dayl-19 Day 2-20 SUMFT) N In X 0.24 N Out X 0.24 Moving Average Mass DELTA-N RCTR#1 Nitrogen Lost X N Lost (Day20-1)ColF-G ColH*100 X 4.8 Balance X Removed = Overall Mass Balance X Removed = Day 1-57 6688 2346 2296 2242 2216 2244 2269 2283 2277 2341 2311 2241 2281 2274 2222 2228 2222 2271 2246 2236 2254 2243 2231 2128 1995 2122 2258 2267 2245 2233 2232 2190 2159 2150 2147 2161 2142 2123 2102 2088 2072 2038 Day 2-58 (FD-FT) Day 58-1 6035 2179 2163 2145 2127 2115 2108 2100 2089 2082 2074 2072 2069 2066 2066 2048 2045 2046 2043 2036 2029 2029 2025 2012 1999 1992 1982 1973 1966 1957 1948 1943 1930 1917 1910 1893 1878 1860 1839 1828 1809 1795 653 167 133 97 89 129 161 184 188 259 237 169 212 208 156 180 177 224 203 200 226 215 206 116 -4 129 276 294 278 275 284 248 229 233 237 268 264 264 263 261 263 243 -646 -271 -308 -370 -354 -245 -129 -176 -206 -151 -157 -40 -61 -63 6 -355 -61 20 -75 -137 -137 -4 -77 -250 -264 -134 -205 -174 -145 -181 -175 -113 -262 -244 -146 -350 -300 -361 -403 -238 -370 -278 Nitrogen Removed 1299 438 441 467 442 374 290 360 394 411 393 209 274 271 150 535 238 204 278 337 362 218 282 366 261 263 481 468 423 457 459 361 491 477 382 618 564 624 666 499 633 521 ColD 17.67 19.43 18.7 19.2 20.8 20.0 16.7 12.8 15.7 17.3 17.5 17.0 9.3 12.0 11.9 6.8 24.0 10.7 9.0 12.4 15.1 16.1 9.7 12.7 17.2 13.1 12.4 21.3 20.7 18.9 20.5 20.6 16.5 22.7 22.2 17.8 28.6 26.3 29.4 31.7 23.9 30.5 25.6 282 AASD* a PHOSPHORUS MASS BALANCE - FIXED-TIME REACTOR Note: Mass Balance has used 58 days of data. DAY 1 2 3 4 5 6 7 S 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 FEED TP <mg/L) 287 322 237 191 177 175 199 134 330 425 201 245 301 165 203 151 264 243 184 206 225 193 242 222 202 185 256 242 198 297 241 210 186 202 238 223 221 210 169 193 0 0 224 222 200 208 204 185 201 180 198 187 237 223 205 196 185 134 116 152 RCTR#1 SUMFEED SUMRCT1 (SUMFD- TP Day1-19 Day 2-20 SUMFT) <mg/L) P In P Out X 0.24 X 0.24 297 DELTA-P Total P RCTR#1 Lost (Day20-1)ColF-G X 4.8 X P Lost ColH*100 ColD 301 Moving Average Mass Balance X Removed = -7.50 306 Overall Mass Balance X Removed = -9.83 306 297 287 Phosphorus 290 Day 1-57 Day 2-58 (FD-FT) Day 58-1 Removed 289 279 292 278 281 289 278 296 273 273 287 279 274 267 270 275 281 267 271 271 263 274 272 216 230 227 220 226 228 231 223 218 223 248 244 245 254 242 244 240 240 245 245 248 246 248 241 245 243 235 243 231 231 2999 3553 -554 -259 -295 1064 1045 1021 1011 1023 1034 1040 1037 1066 1045 991 1014 1013 991 996 996 1017 1007 1002 1008 999 991 945 887 941 999 1003 991 982 979 956 941 938 939 947 943 939 933 927 919 900 1309 1301 1292 1285 1281 1276 1272 1267 1264 1259 1258 1242 1228 1216 1198 1186 1176 1162 1149 1135 1125 1119 1112 1103 1100 1093 1087 1081 1073 1067 1074 1078 1082 1089 1093 1097 1100 1103 1109 1110 1106 -245 -256 -271 -274 -258 -242 -231 -230 -197 -214 -267 -228 -215 -225 -202 -191 -159 -155 -147 -127 -126 -128 -167 -216 -159 -94 -84 -90 -91 -88 -118 -137 -144 -150 -146 -153 -161 -169 -181 -192 -206 -110 -163 -173 -149 -77 -96 -91 -86 -77 -86 -29 -312 -283 -245 -365 -226 -216 -269 -269 -269 -211 -106 -149 -173 -62 -139 -130 -110 -163 -130 139 86 91 134 72 82 58 58 120 38 -82 -135 -93 -98 -125 -181 -146 -140 -144 -120 -128 -238 84 68 20 163 35 57 114 122 141 85 -23 -18 -44 -97 45 46 20 72 42 -257 -223 -235 -285 -218 -235 -218 -227 -301 -230 -125 -12 -8 -9 -12 -17.7 -14 -13 -13 -11 -12.2 -24.1 8 6 2 16 3 5 11 12.1 14.0 8 -2 -1 -4 -10 4 4 2 7.4 4.3 -26.9 -23.7 -25.1 -30 -23 -24 -23 -24 -32 -25.1 -13.8 283 AASD#2 ALKALINITY MASS BALANCE - FIXED-TIME REACTOR Note: Mass Balance has used 58 days of data. DAY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 FEED ALK (mg/L) 204 194 188 150 180 178 165 136 172 164 180 190 208 220 178 162 220 190 166 152 152 128 160 154 150 138 168 164 148 182 186 192 152 170 256 204 248 220 176 200 0 0 180 190 196 208 188 192 184 196 186 190 232 218 220 220 238 166 160 218 RCTR#1 SUMFEED SUMRCT1 (SUMFD- ALK Day1-19 Day 2-20 SUMFT) (mg/L) ALK In ALK Out X 0.24 X 0.24 DELTA-A ALK RCTR#1 Lost (Day20-1)ColF-G X 4.8 X ALK Lost ColH*100 ColD 136 144 166 176 145 155 140 124 124 124 120 134 128 132 142 138 130 128 142 138 140 134 136 128 126 134 124 124 134 138 152 176 154 148 170 144 148 154 154 164 166 166 158 152 158 152 156 156 150 164 152 154 152 160 158 164 164 164 206 226 Moving Average Mass Balance X Removed Overall Mass Balance X Removed = 13.82 15.49 Day 1-57 Day 2-58 2533 2006 Alkalini (FD-FT) Day 58-1 Removed 527 134 392 ty 827 814 804 790 792 786 779 773 780 779 775 775 774 770 754 752 775 771 785 798 804 815 784 746 795 851 864 874 880 890 891 893 892 901 916 907 911 904 908 906 896 631 630 623 613 609 602 600 600 600 603 607 612 623 628 630 637 641 646 648 652 658 666 673 680 686 692 699 707 712 715 718 712 712 713 710 714 718 720 722 732 747 196 184 182 177 183 184 179 172 180 176 168 164 151 142 124 115 134 125 136 145 145 149 111 66 109 158 166 168 168 176 173 181 180 188 205 193 193 184 186 173 149 10 -19 -154 -192 -82 -139 -29 0 0 48 86 86 230 106 29 154 67 96 58 77 115 154 144 144 125 115 134 154 106 58 58 -115 0 19 -48 67 77 48 48 202 288 186 203 335 369 265 323 208 172 180 128 81 77 -79 36 96 -39 67 29 79 69 30 -4 -33 -78 -16 43 31 14 62 118 116 297 180 169 253 126 116 136 138 -28 -139 22. 25. 41. 46. 33. 41. 26. 22. 16, 10. 10. -10. 4. 12. -5. 8. 3. 10. 8. 3. -0. -4. -10. -2. 5. 3. 1. 7. 13. 13. 33. 20. 23.1 18.8 27.7 13.9 12.8 15.0 15.2 -3.1 -15.5 284 AASD#2 TOTAL SUSPENDED SOLIDS MASS BALANCE - REAL-TIME REACTOR Note: Mass Balance has used 58 days of data. DAY FEED RCTR#2 SUMFEED SUMRCT2 (SUMFD- DELTA RCT SOLIDS X SOLIDS MLSS MLSS Day1-19 Day 2-20 SUMRT) (Day20-1) RED REDUCED Cmg/L) (mg/L) X 0.24 X 0.24 *4.8 ColF-G ColH*100 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 10610 9596 4040 5986 5384 5914 6078 7454 10356 9210 6074 7854 9562 5190 6380 4924 8634 7826 5962 6436 7298 6292 7512 6574 6114 5586 7400 7242 5632 8450 6836 6182 5522 6160 7442 6982 6798 6868 5170 5974 0 0 6870 6630 6016 6256 6086 5472 6000 5498 5604 5438 6632 6082 5524 5436 5560 4714 4300 6118 6658 6820 6768 6580 6558 6374 6222 6132 6208 6402 6612 6488 6392 6660 6404 6414 6150 6338 6290 6250 6204 6304 6222 6136 5856 5964 5832 5806 5962 5824 5938 5860 5934 5910 5794 5818 5812 5866 5768 5678 5630 5592 5448 5574 5510 5651 5514 5442 5406 5530 5454 5464 5068 5152 5192 5068 5098 4942 4976 4762 Moving Average Mass Balance X Removed = Overall Mass Balance X Removed = Day 1-57 90746 32888 31886 31335 31875 32242 32527 32575 32457 32444 31697 30838 31408 31164 30353 30432 30380 30984 30588 30341 30558 30254 29937 28427 26624 28344 30059 30162 29887 29610 29571 28983 28662 28524 28503 28617 28290 27940 27613 27300 27190 26788 Day 2-58 80948 29295 29147 29036 28950 28848 28724 28662 28590 28494 28388 28199 28067 27939 27765 27647 27498 27418 27292 27190 27074 26948 26786 26635 26470 26402 26293 26250 26180 26055 25955 25857 25759 25647 25445 25290 25140 24962 24777 24579 24411 24202 (FD-RT) Day 58-1 9798 3593 2739 2299 2926 3393 3803 3913 3867 3950 3309 2639 3341 3225 2588 2786 2882 3566 3296 3151 3484 3306 3150 1791 154 1941 3765 3912 3707 3555 3617 3126 2903 2877 3059 3326 3150 2979 2836 2720 2779 2586 -8237 -1958 -2957 -2227 -1718 -2026 -2486 -1238 -1440 -1930 -2112 -3782 -2640 -2554 -3485 -2371 -2976 -1594 -2525 -2035 -2314 -2525 -3235 -3024 -3302 -1354 -2179 -869 -1402 -2496 -2006 -1958 -1949 -2256 -4042 -3082 -3005 -3571 -3686 -3965 -3370 -4166 Solids Reduced 18034 5552 5696 4526 4644 5419 6289 5151 5307 5880 5421 6421 5981 5778 6072 5157 5858 5160 5820 5186 5797 5831 6385 4815 3456 3295 5944 4781 5109 6051 5623 5085 4852 5133 7100 6408 6155 6550 6522 6685 6149 6752 ColD 18.49 19.87 16.9 17.9 14.4 14.6 16.8 19.3 15.8 16.4 18.1 17.1 20.8 19.0 18.5 20.0 16.9 19.3 16.7 19.0 17.1 19.0 19.3 21.3 16.9 13.0 11.6 19.8 15.8 17.1 20.4 19.0 17.5 16.9 18.0 24.9 22.4 21.8 23.4 23.6 24.5 22.6 25.2 •o o *— i n O T - CM CM II 1! > S ee. « u u c a mm* is a <o 10 is X * i ID u dl > < o c > o X II "8 > o G 5 cc »t 0) o c •0 .̂  IB m <0 10 IS X 10 t . 41 > o 0> y ~o fi •« u o 3 O "85 • •* oo r>- in to •o >• • IS a «•*» t - o ne ro • o Q o u . >̂ oo i n CM I CM CM 00 *a IS Q f - CM i n i n • «t « - -* t»- >* IS Q N ' 0 0 > « I ^ M « 1 0 ( M M M > 0 > < t n i M O ' O O i n N O > O N S l f l ^ M M I M O N M O S N N ' O O r - N c o o > i n i n c o o < o r - o > c o « - o o c M O « - o o o o o » - r n o i n M O N . € O C M « - o > e o o o i n i o r o i n m < o i » i ~ » » - r - « - » - T - C M » - " - » - « - C M C M « - C M « - C M « - C M » - C M C M C M C M » - » - « - » - « - C M C M * - » - « - C M C M t M C M C M C M C M C M m o o » - > * o c M i n ^ o o c M O r o O K ) m m » - « * C M i n r o o > > » - * o o > o « - o > 0 ' 0 » - e o c M T - ~ * « - i n m t - - o n M » - » 0 ' N o - i t - o 9 i n o o » N c o o s n ' O O f l } « ( M o i M n O ' » ' O n < - n i n ' O o n o o o i M o o » - o « - c o i n i n i n « - e 5 i n « t f » - i n e o - * e o « - r ' » r - - * e o - O f O C M e o c M i n i o * - i n » t » » o i n i n c o c , - - c o « - t o N O O N N N - f O M ' 0 ' l ^ l V O I » - J ' O r ^ O N O O O ' 0 » ^ ( M ( 0 0 » ' O K | r o i n N O i n i n O o > 0 ' O i M O i n ' - ( M ' * - i i o i n ( o o O i n - » o o S | 0 > - ( M < j M i n » - > - K i i n S < | i M ' - o o ' - 0 ' - r O ' - N ~ t « - ^ » o - * S . - o K c M i n r » . o o o o o o i n t o o i n S - « - S < 0 ' O o c M m o o < O v t i n > o » - s » i n O " - c M m e o «- CM «— * - « - * - I I *— * - CM CM «— CM*— CM * - * - »— «- CM CM CM CM T— «— I » - » - « - « — • — *~fOCMCMtOfOtOCMC\l l l l l l i l l l l l l i t l l i l l l l l l l I I I I I I I I I I I I I I r o e o r v i r ^ o o > o p M 3 eo c i K- . . . - . _ _ . _ r . - . t » i t ^ T - < o r o t ^ N - « - K > - * t o » * o . > o c > T - o r ^ i n i n ' r - » - o > c o ~ » o c M o o r o t ^ c M < - c o * - c > c M F - h o S ^ c M « - > g ^ c > K - i n c M C > ^ ^ c > * f O C M i n ^ c > < o o O ( M i n > o c O T - h » r ' ~ * - t o tOCMCMfOfOtOIOfOtOfOCMfOfOCMCMCMIOIOrOIOIOfOCM r M M M M I O M M I M I M N K I I M I M I M I M N I M « * « - o o c M « - i n r o > 0 > 0 - * o > o o o o i n o « - i n o > i o » - 0 > o i n o o o o r ^ M N . < o « - ' - i n c M N . i n c > < o - * t ^ c M i n > o t o o v M i n » - « - C M r - t ^ i n c o o ^ « - C M « - o o i n r - ^ o e o c M i o ; t r » o > » - > o ~ » ' - < o o » » « - r > - c M « - « - o o o » e o o o r - < o m v * c M » - o o o o e o f ~ - ' O J ' i o c M « - « - o o < M O S 4 < o > t n i M O O ' S ' 0 4 I O K l K I | i l N N r v l M N N N N N I M N < - r r - ^ r t - r f - f ^ r - i - 0 0 0 0 0 0 0 0 0 » 0 . » 0 > C M C M C M C M C M C M C M C M C M C M C M C M C M C M C M t M C M C M C M C M C M C M C M C M C M C M f M C M C M C M C M C M C M C M C M C M « - « - « - « - « r M C > n n S ( \ i N o O ' » > o - » 8 < t o > « 0 ' 0 > o i c i < - > i < > » - « - < - o o j N n < | « ) > t ' - o o « o o ) r - i o < - 0 ' l \ l N N U l N < n N N o n i O > O C > 0 ( > > « > - 0 ' « - 0 > - O M ( > M S C O i n n M C O m ^ - » i n l M < O i n M ( M O > O i O t n > o o > 0 ' 0 > 0 ' 0 « i n i n i n ^ i r v t i n i n ^ i n v t J K i « - M - » ^ - » > i > » i < i n K i M i < i K i ( M r M f M < M r - CMCMfMCMCMCMCMCMCMCMCMCMCMCMCMCMCMCMCMCMCMCMCMCMCMCMCMCMCMCMCMCMCMCMCMCMCMCMCMCMCM S( M M S t O K > - < - W f M t - N S e O - t < - < - > * 0 > N O ' O i n i M O i n i n Q r - ^ 0 ' - ' - C M N ^ < - t - i n ' - « » ( M I M < 1 M S l M N 0 > 0 " g - l W > > 0 ' « 0 v a > 0 i n < - > 1 0 ' i - r - r - O t 0 M 0 - } 0 ) « f ' - O O C 5 t 0 r - K ) T - _ . . _ ! . _ .. ^ T K i e O - 0 0 0 0 > ^ > - 0 - > - 0 > O M O > M M O i n i O M « O i n - J - I l f l l M B i n K l ( M O • rvl rvl rvl rvl rvl M rvl | \1 rvl rvi rvl rvl rvl rvl rvl rvl l u rvl rvl rvl rvi rvl rvl rvl rvl rvi rvi rvl rvl rvi rvl N N N n ^ r > i o ^ < t i \ i o a ) 0 4 N < ) o a < ) O N « ^ N ^ N 4 i n o o o a N t ^ < ) a N e o « ) r \ i g a ^ > i < Q t a s o i \ i i \ i > r o « ) q < o ^ < f o > t c o o o O v » c > f o c M K c M C M O c > v o r ^ o t O i M i n i n v O f O C > c > c o c M r O o c > r ^ » i h - o o i n o f o « - c M r ^ K o ™ > » I O N ( \ I O O > I O O i O N < - i - | O t - < - o > O O C M > O O a S N > 0 ' O K ' O K N K S ^ ' 0 ' < I N ' O i n i n ^ M - J i n i n ^ n n ' * l < l K 1 0 » - > - O O O O O i inininininin^«*v*ininininininin«*inin^^inin^~»^^^vt>*^s»>j^>rvtvt^>*^*^^*>»«*-*^»-*>*>t>»«*>t>*>»>»>»~*ro>tM <Q CO CM CM 00 CM CO •o «- -o CM to to in «* CO to O •* 00 o CO f- tO -* >t -» -tf C M ^ > 0 < 0 O C 0 « * O C 0 0 0 v t O O O 0 0 O ^ » C 0 0 0 O O O ~ » C 0 O C M % 0 O O O 0 0 ^ t O O C M - 4 - O < 0 C 0 i - ^ m ^ ^ K i N a ^ N i n < o v O < o i M i n < O N r M f O t o « - t o r ^ « * e g o h - f o t o r \ i c o o i n f o O v i - i n o o o m O i n * - i n o * - c o * o * o c M O ^ • ^ o * - o ^ t c o i n i n « 4 , > * O N t ^ t i n o * o « — ^ < o m ^ O m i n N t i n > o i n m t n > f ^ i n i n v t i n - J - s t ^ ^ t ^ t ^ i n ^ v t v ^ ^ t o t o i n ^ N M ^ m ^ N e o t K O i - i \ i n « t i n « N o j o > o » - N M v f i n * N c o » o » - ( \ i M - * i n ^ N o j o » o ^ c g n ^ u i > o N « o o v o ' - f J n ^ i n ' O N < o < > ' 0 « - « - « - ' - « - « - « - ' - « - » - c M C M C M C M C M C M C M C M C M i M i O f o t o t o i o t o f O t o t o t o > * - * > » ~ * v t - 4 - - * « * - 4 ' ~ » i n i n i n i n i n i n i n i n i n i n ^ AASD#2 NITROGEN MASS BALANCE - REAL-TIME REACTOR Note: Mass Balance has used 58 days of data. DAY FEED RCTR#2 SUMFEED SUMRCT2 (SUMFD- (NOx + (TKN + Day1-19 Day 2-20 SUMRT) NOx) NOx) N In N Out (mg/L) (mg/L) X 0.24 X 0.24 DELTA-N Nitrogen RCTR#2 Lost (Day20-1)ColF-G X 4.8 X N Lost ColH*100 Co ID 1 652.90 2 735.48 3 536.08 4 437.18 5 401.10 6 395.92 7 438.49 8 294.20 9 647.48 10 713.72 11 464.09 12 563.69 13 688.07 14 397.14 15 475.21 16 355.23 17 616.35 18 552.07 19 408.69 20 446.18 21 511.16 22 426.18 23 554.24 24 508.10 25 453.41 26 414.25 27 559.24 28 520.34 29 423.16 30 631.57 31 533.57 32 472.31 33 423.23 34 450.30 35 556.24 36 513.26 37 510.30 38 486.30 39 400.74 40 457.39 41 0.00 42 0.00 43 517.22 44 510.36 45 453.57 46 465.25 47 470.04 48 422.56 49 456.62 50 402.42 51 436.65 52 408.88 53 509.15 54 475.21 55 436.35 56 422.65 57 429.37 58 333.27 59 316.31 60 429.21 527.01 473.19 Moving Average Mass Balance X Removed = 530.51 Overall Mass Balance X Removed = 498.19 472.91 462.16 Nitrogen 478.37 Day 1-57 Day 2-58 (FD-RT) Day 58-1 Removed 456.44 455.19 472.05 480.04 461.61 470.44 475.96 463.56 470.6 432.37 442.06 435.47 455.57 438.32 444.28 446.37 446.47 437.35 439.57 452.94 438.59 427.3 408.08 446.5 442.28 429.75 429.31 425.66 420.69 439.47 404.42 430.14 408.26 414.67 401.61 395.99 410.74 402.25 376.81 411.34 402.38 396.27 391.57 385.15 386.6 354.68 369.69 359.28 350.96 364.49 337.28 345.15 354.3 6688 5869 819 -911 1730 2346 2296 2242 2216 2244 2269 2283 2277 2341 2311 2241 2281 2274 2222 2228 2222 2271 2246 2236 2254 2243 2231 2128 1995 2122 2258 2267 2245 2233 2232 2190 2159 2150 2147 2161 2142 2123 2102 2088 2072 2038 2133 2124 2104 2091 2085 2079 2070 2069 2065 2054 2037 2033 2026 2015 2007 1996 1994 1993 1986 1979 1972 1965 1954 1942 1936 1927 1909 1902 1896 1893 1880 1866 1856 1838 1825 1810 1789 1779 1757 1742 1727 213 171 138 124 159 190 214 209 276 256 204 248 247 207 221 226 277 253 250 275 271 266 174 53 186 331 359 343 336 339 310 293 294 309 336 332 335 323 332 331 311 -343 -167 -414 -249 -127 -119 -186 -17 -80 -215 -345 -73 -135 -222 -164 -216 -56 -12 -149 -122 -144 -142 -215 -242 -128 -179 -365 -131 -120 -57 -264 -274 -207 -358 -269 -295 -425 -192 -446 -303 -290 556 339 552 373 286 310 400 225 356 471 549 320 382 428 386 442 333 265 399 397 416 408 389 295 314 510 724 473 456 396 574 567 502 667 605 626 759 515 777 634 601 20.59 25.87 23.7 14.8 24.6 16.8 12. 13. 17. 9. 15. 20. 24. 14. 16.8 19.3 17.3 19.9 14.7 11.8 17.9 17.6 18.5 18.3 18.3 14.8 14.8 22.6 31.9 21.1 20.4 17.7 26.2 26.3 23.3 31.1 28.0 29.3 35.8 24.5 37.2 30.6 29.5 oo CN n « 0 ( M o - < r - r - ^ i n - ( i O ( M > 0 ' < i O M N n ' - ' 0 0 i n o N O ( M ( M > - i n ^ M t o o n M M i n N » r o C 0 4 ) N I M i n ' ' O I > N 0 4 l < l > 0 0 ' 0 ' O O N ' - I V I O O O O " « I M n a S M M N 4 0 » n N t O O i n O <l I eg n C/> 3 a </> o c <0 V) to u —» -M I (0 I A U . «J O —• O _l o *- u a. t\i . - • =8: i CO < a o • I - ( - CM ~* _J O > . 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DAY 1 2 3 4 5 6 7 3 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 FEED ALK (mg/L) 204 194 188 150 180 178 165 136 172 164 180 190 208 220 178 162 220 190 166 152 152 128 160 154 150 138 168 164 148 182 186 192 152 170 256 204 248 220 176 200 0 0 180 190 196 208 188 192 184 196 186 190 232 218 220 220 238 166 160 218 RCTR#2 ALK (mg/L) 140 140 174 166 142 138 140 124 124 110 126 128 130 128 130 136 134 132 138 142 142 134 134 130 128 128 128 128 132 140 142 176 156 148 180 148 148 150 160 158 150 168 144 150 156 164 156 160 152 160 154 158 162 162 158 162 170 166 218 222 SUMFEED SUMRCT2 0ay1-19 Day 2-20 ALK In X 0.24 ALK Out X 0.24 (SUMFD- SUHRT) DELTA-A RCTR#2 ALK Lost (Day20-1)ColF-G X 4.8 Moving Average Mass Balance X Removed = Overall Mass Balance X Removed = Day 1-57 Day 2-58 2533 827 814 804 790 792 786 779 773 780 779 775 775 774 770 754 752 775 771 785 798 804 815 784 746 795 851 864 874 880 890 891 893 892 901 916 907 911 904 908 906 896 1998 620 620 611 603 600 598 595 596 597 602 605 609 620 626 631 641 645 648 651 656 660 663 672 675 680 687 696 702 709 712 716 711 711 715 710 713 716 721 722 737 754 (FD-RT) 535 207 194 194 187 192 188 185 177 184 177 169 167 155 144 123 111 130 122 133 142 144 152 113 71 115 164 169 172 171 179 175 182 180 186 205 194 194 183 186 169 142 Day 58-1 125 10 10 -192 -154 -58 -48 -58 19 19 106 67 67 221 134 86 211 67 77 58 86 77 77 163 67 106 134 173 134 134 58 86 -106 10 67 -86 48 67 96 29 288 346 Alkalini Removed 410 198 185 386 341 250 236 242 158 165 71 102 99 -66 10 37 -100 63 46 76 56 67 75 -50 4 10 29 -4 37 36 121 88 288 171 119 292 146 127 87 157 -119 -204 X ALK Lost ColH*100 ColD 13.41 16.19 ty 23.9 22.7 48.0 43.1 31.5 30.1 31.1 20.4 21.1 9.1 13.2 12.8 -8.6 1.2 4.9 -13.3 8.1 5.9 9.7 7.0 8.4 9.2 -6.4 0.5 1.2 3.4 -0.4 4.3 4.1 13.6 9.9 32.2 19.2 13.2 31.9 16.1 14.0 9.6 17.3 -13.1 -22.7 289 APPENDIX 6 SOME BIO-P CALCULATIONS Page A Inorganic P Additions to Bio-P*l 290 B Acetate Additions 290 290 APPENDIX 6 SOME BIO-P CALCULATIONS A Inorganic P Additions Adding Na2HP04 M.W. = 142 gms/mole contains 31 gms/mole of P. Since target is around 7 mg/L P in the Feed Bucket... Thus, need 142 x 7 = 32 mg Na2HP04/Litre of Influent. 31 Feed Bucket contains approximately 3 Carboys (approx. 48 L ) . . . Add 32 mg x 48 L x 1 cm = 1 . 5 gms Na2HP04/Feed Bucket Fill L 1000 mg B Sodium Acetate Additions Calculate COD equivalent of Acetate... (Assume complete oxidation) NaCH3COO + 2 02 <=> NaHC03 + C02 + H20 82 gms 64 gms 84 gms 44 gms 18 gms If assumed to add 30 mg/L RBD COD (must be >= 25 mg/L) 82 x 30 = 38 rag of NaAc" / L of influent must be added 64 Each Influent Feed is 2.4 L; Acetate Pump delivers 3 0 mL/6 min. Thus.. 3 8 m g x 2 . 4 L x 1 x 1000 mL x 1 am 30 mL L 1000 mg = 3.04 gms/L Acetate Solution must be made up in volumetric flask APPENDIX H CHEMICAL DATA - BIO-P Parameter Page Solids Concentrations B i o - P # l 292 Bio-P*2 293 Nitrogen and Phosphorus Feed (Bio-P*l and Bio-P*2) 294 Fixed-Time Reactor (Bio-P*l and Bio-P#2) 295 Real-Time Reactor (Bio-P#l and Bio-P#2) 296 pH, Alkalinity and Carbon Feed (Bio-P#l) 297 Fixed-Time Reactor (Bio-P*l) 297 Real-Time Reactor (Bio-P*l) 298 Feed (Bio-P*2) 299 Fixed-Time Reactor (Bio-P*2) 299 Real-Time Reactor (Bio-P#2) 3 00 Carbon Decay Data 301 BIO-P #1 Feb/19/91-Har/30/91 Solids Concentrations Day Date FEED FT RCTR SOLIDS FT EFFLUEMT SOLIDS RT RCTR SOLIDS RT EFFLUENT SOLIDS of TSS VSS Ratio TSS VSS Ratio TSS VSS Ratio TSS VSS Ratio TSS VSS Ratio Run mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L 1 Feb/19/91 99 89 0.90 2212 1722 0.78 2 2 1.00 2366 1880 0.79 3 3 1.00 2 /20/ 3 /21/ 4 /22/ 5 /23/ 80 69 0.86 2352 1804 0.77 2 2 1.00 2612 2012 0.77 2 2 1.00 6 /24/ 7 /25/ 8 /26/ 9 /27/ 77 68 0.88 2128 1632 0.77 11 11 1.00 2384 1822 0.76 3 3 1.00 10 /28/ 11 Mar/01/91 12 /02/ 13 /03/ 116 105 0.91 2376 1834 0.77 2 2 1.00 2466 1892 0.77 1 1 1 00 14 /04/ 15 /05/ 16 /06/ 17 /07/ 97 87 0.90 2342 1826 0.78 4 4 1.00 2404 1870 0.78 2 2 1.00 18 /08/ 19 /09/ 20 /10/ 21 /11/ 105 93 0.89 2014 1542 0.77 5 5 1.00 2156 1636 0.76 5 5 1.00 22 /12/ 23 /13/ 24 /14/ 25 /15/ 113 94 0.83 1620 1208 0.75 5 5 1.00 1890 1392 0.74 4 4 1 00 26 /16/ 27 /17/ 28 /18/ 29 /19/ 107 96 0.90 1860 1344 0.73 5 5 1.00 2012 1428 0.71 5 5 1 00 30 /20/ 31 /21/ 32 /22/ 33 /23/ 121 107 0.89 2170 1618 0.75 5 5 1.00 2252 1646 0.73 4 4 1.00 34 /24/ 35 /25/ 36 /26/ 37 /27/ 85 75 0.88 2166 1625 0.75 1 1 1.00 2272 1696 0.75 2 2 1.00 38 /28/ 39 /29/ 40 /30/ Maximum 121 107 0.91 2376 1834 0.78 11 Mean 100 88 0.88 2124 1616 0.76 4 Minimum 77 68 0.83 1620 1280 0.73 1 Std. Dev. 15 13 0.02 226 196 0.02 3 11 1.00 2612 2012 0.79 4 1.00 2281 1727 0.76 1 1.00 1890 1392 0.71 3 0.00 205 195 0.02 5 3 1 1 5 3 1 1 1.00 1.00 1.00 0.00 BI0-P #2 Apr/22/91-Hay/31/91 SoI ids Concentrations Day Date FEED FT RCTR SOLIDS FT EFFLUENT SOLIDS RT RCTR SOLIDS RT EFFLUENT SOLIDS of TSS VSS Ratio TSS VSS Ratio TSS VSS Ratio TSS VSS Ratio TSS VSS Ratio Run mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L 1 Apr/22/91 174 158 0.91 3018 2648 0.88 10 10 1.00 3026 2650 0.88 10 10 1.00 2 /23/ 3 /24/ 4 /25/ 5 /26/ 181 162 0.90 2578 2222 0.86 2 2 1.00 2582 2216 0.86 2 2 1.00 6 /27/ 7 /28/ 8 /29/ 9 /30/ 146 129 0.88 2440 2082 0.85 4 4 1.00 2460 2106 0.86 4 4 1.00 10 May/01/91 11 /02/ 12 /03/ 13 /04/ 79 71 0.90 2486 2074 0.83 10 10 1.00 2494 2066 0.83 8 8 1.00 14 /05/ 15 /06/ 16 /07/ 17 /08/ 86 79 0.92 2084 1722 0.83 6 6 1.00 2108 1732 0.82 6 6 1.00 18 /09/ 19 /10/ -' 20 /11/ 21 /12/ 78 73 0.94 2128 1756 0.83 6 6 1.00 2010 1664 0.83 7 7 1.00 22 /13/ 23 /14/ 24 /15/ 25 /16/ 65 59 0.91 1998 1616 0.81 6 6 1.00 1824 1484 0.81 8 8 1.00 26 /17/ 27 /18/ 28 /19/ 29 /20/ 78 70 0.90 1986 1568 0.79 4 4 1.00 1806 1428 0.79 4 4 1.00 30 /21/ 31 /22/ 32 /23/ 33 /24/ 86 78 0.91 1598 1266 0.79 8 8 1.00 1630 1276 0.78 7 7 1.00 34 /25/ 35 /26/ 36 /27/ 37 /28/ 99 88 0.89 1628 1297 0.80 5 5 1.00 1656 1290 0.78 2 2 1.00 38 /29/ 39 /30/ 40 /31/ Maximum 181 162 0.94 3018 2648 0.88 10 Mean 107 97 0.90 1825 1825 0.83 6 Minimum 65 59 0.88 1266 1266 0.79 2 Std. Dev. 41 36 0.01 410 410 0.03 2 10 1.00 3026 2650 0.88 6 1.00 2159 1791 0.82 2 1.00 1630 1276 0.79 2 0.00 439 431 0.03 10 10 1.00 6 6 1.00 2 2 1.00 3 3 0.00 BIO-P #1 Feb/19/91-Mar/30/91 FEED Nitrogen and Phosphorus Day Date Ortho TP NOx NH3 TKN of -P Run mg/L mg/L mg/L mg/L mg/L 1 Feb/19/91 7.42 9.9 0.09 17.0 2 /20/ 3 /21/ 4 /22/ 5 /23/ 7.64 0.14 17.0 6 /24/ 7 /25/ 8 /26/ 9 /27/ 4.91 0.18 10 /28/ 11 Mar/01/91 12 /02/ 13 /03/ 7.43 9.1 0.00 12.5 14 /04/ 15 /05/ 16 /06/ 17 /07/ 6.21 0.11 11.3 18 /08/ 19 /09/ 20 /10/ 21 /11/ 6.21 0.06 13.0 22 /12/ 23 /13/ 24 /14/ 25 /15/ 5.55 0.35 13.8 26 /16/ 27 /17/ 28 /18/ 29 /19/ 6.72 9.7 0.06 9.8 30 /20/ 31 /2V — - 32 /22/ 33 /23/ 6.80 0.21 10.7 34 /24/ 35 /25/ 36 /26/ 37 /27/ 5.53 0.17 12.0 38 /28/ 39 /29/ 40 /30/ 28.2 26.8 30.3 BIO-P #21 Apr/22/91-Hay/31/91 FEED Nitrogen and Phosphorus Day Date Ortho TP NOx NH3 TKN of -P Run mg/L mg/L mg/L mg/L mg/L 1 Apr/22/91 2.41 6.3 0.16 11.95 41.2 2 /23/ 3 /24/ 2.61 0.30 4 /25/ 5 /26/ 2.45 0.04 12.59 6 /27/ 7 /28/ 2.53 0.08 8 /29/ 9 /30/ 2.56 0.17 11.97 10 May/01/91 11 /02/ 3.18 0.10 12 /03/ 13 /04/ 1.60 3.7 0.14 11.64 24.0 14 /05/ 15 /06/ 1.69 0.09 16 /07/ 17 /08/ 1.72 0.20 12.04 18 /09/ 19 /10/ 1.95 0.22 20 /11/ 21 /12/ 2.04 0.10 12.54 22 /13/ 23 /14/ 2.04 0.22 24 /15/ 25 /16/ 2.13 0.19 13.78 26 /17/ 27 /18/ 2.15 4.1 0.14 27.7 28 /19/ 29 /20/ 1.99 0.19 12.00 30 /21/ 31 /22/ 2.03 0.11 32 /23/ 33 /24/ 2.14 0.19 12.33 34 /25/ 35 /26/ 2.17 0.19 36 /27/ 37 /28/ 2.14 0.27 12.98 38 /29/ 39 /30/ 2.29 ---- 0.18 40 /31/ Maximum 7.64 9.7 0.35 17.0 30.3 Mean 6.44 9.5 0.14 13.0 28.4 Minimum 4.91 9.1 0.00 9.8 26.8 Std. Dev. 0.87 0.4 0.09 2.4 1.4 Maximum 3.18 6.3 0.30 13.78 41.2 Mean 2.19 4.7 0.16 12.38 31.0 Minimum 1.60 3.7 0.04 11.64 24.0 Std. Dev. 0.36 1.1 0.06 0.60 7.4 BIO-P #1 Feb/19/91-Mar/30/91 FT RCTR Nitrogen and Phosphorus Day Date Ortho Percent NOx of -P P Run mg/L (X) NH3 Percent N mg/L mg/L (X) 1 Feb/19/91 3.39 2.95 2 /20/ 3 /21/ 4 /22/ 5 /23/ 7.46 2.92 6 /24/ 7 /25/ 4.93 8 /26/ 9 /27/ 8.27 3.23 10 /28/ 11 Mar/01/91 12 /02/ 7.79 0.1 4.81 8.22 8.21 9.22 -- 5.04 5.32 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 /03/ 4.60 3.10 7.48 M/D 5.31 /04/ /05/ 5.87 /06/ /07/ 8.10 2.92 7.61 8.05 8.44 N/D 5.42 /08/ /09/ 4.76 /10/ /1V /12/ /13/ 5.29 /14/ /15/ 9.60 3.50 /16/ /17/ 3.26 — - /18/ /19/ 10.70 3.56 8.97 N/D 5.16 /20/ 9.30 3.35 9.26 N/D 5.50 8.09 8.24 N/D 5.35 8.35 /21/ /22/ /23/ /24/ /25/ /26/ /27/ /28/ /29/ /30/ 5.88 6.44 7.71 3.45 6.64 N/D 5.53 3.89 6.31 7.12 3.52 6.68 N/D 5.72 4.78 9.43 Maximum 10.70 3.56 9.43 0.1 5.72 Mean 6.38 3.25 7.97 N/D 5.32 Minimum 3.26 2.92 6.31 N/D 4.81 Std. Dev. 2.17 0.25 0.94 M/D 0.25 BIO-P #2 Day of Run Apr/22/91-May/31/91 FT RCTR Nitrogen and Phosphorus Date Ortho Percent NOx NH3 Percent -P P N mg/L (X) mg/L mg/L (X) 1 Apr/22/91 0.03 1.12 7.68 N/D 5.45 2 /23/ 3 /24/ 0.02 9.18 4 /25/ 5 6 7 8 9 /26/ mi m/ /29/ /30/ 10 May/01/91 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 /02/ /03/ /04/ /05/ /06/ /07/ /08/ /09/ /10/ /1V /12/ /13/ /14/ /15/ /16/ /17/ /18/ /19/ /20/ /21/ /22/ /23/ /24/ /25/ /26/ /27/ /28/ /29/ /30/ /31/ Maximum Mean Minimum Std. Dev. 0.02 0.02 0.03 0.03 0.00 0.02 0.33 0.12 2.07 0.16 2.07 0.12 1.73 0.11 1.90 0.11 1.51 0.09 2.07 0.52 0.00 0.78 1.48 2.06 2.29 2.75 2.57 3.05 3.13 3.15 3.36 3.36 2.50 1.12 0.71 9.71 8.33 8.96 9.22 9.16 7.47 7.19 7.38 8.41 8.24 8.66 8.62 8.21 8.52 8.73 8.71 8.95 8.53 9.71 8.49 7.19 0.65 N/D N/D N/D N/D N/D N/D N/D N/D N/D N/D N/D N/D N/D 6.27 6.41 6.75 6.82 6.50 6.37 6.15 6.11 6.35 6.82 6.32 5.45 0.36 Note: N/D - Not Detectable Less than lowest standard 0.05 mg/L Nitrogen and Phosphorus Nitrogen and Phosphorus Day of Run 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 Date Feb/19/91 /20/ /2V mi /23/ /24/ /25/ /26/ mi mi Mar/01/91 1021 /03/ /04/ /05/ 1061 1071 1081 1091 mi mi mi mi /14/ 1151 1161 mi mi mi 120/ mi 1221 mi mi mi 126/ mi 1281 1291 /30/ Maximum Mean Minimum Std. Dev. Ortho -P mg/L 5.10 5.30 4.20 6.90 4.37 5.21 7.00 5.13 8.01 4.05 8.49 2.51 8.80 4.49 7.32 5.72 5.51 3.01 8.80 5.60 2.51 1.70 Percent NOx P (%) 2.53 2.63 3.06 3.27 2.73 3.28 3.36 4.07 3.69 3.68 4.07 3.20 2.53 0.40 mg/L 7.83 8.07 8.08 8.75 5.91 6.57 7.13 3.89 8.30 5.51 12.39 7.61 12.89 8.65 9.19 2.69 8.85 6.69 12.89 7.70 2.69 2.40 NH3 mg/L 0.2 N/D N/D N/D 0.1 N/D N/D 2.5 2.5 0.4 N/D 0.8 Percent N m 4.53 4.78 4.93 5.19 4.87 5.02 4.94 5.07 5.00 5.18 5.19 4.90 4.53 0.10 Day Date Ortho of -p Run mg/L 1 Apr/22/91 0.03 2 /23/ 3 /24/ 0.03 4 /25/ 5 /26/ 0.03 6 /27/ 7 /28/ 0.02 8 /29/ 9 /30/ 0.02 10 May/01/91 11 /02/ 0.03 12 /03/ 13 /04/ 0.01 14 /05/ 15 /06/ 0.02 16 /07/ 17 /08/ 1.59 18 /09/ 19 /10/ 0.50 20 /11/ 21 /12/ 1.92 22 /13/ 23 /14/ 0.72 24 /15/ 25 /16/ 1.36 26 /17/ 27 /18/ 0.20 28 /19/ 29 /20/ 0.95 30 /21/ 31 /22/ 0.15 32 /23/ 33 /24/ 0.86 34 /25/ 35 /26/ 0.76 36 /27/ 37 /28/ 1.13 38 /29/ 39 /30/ 0.12 40 /31/ Percent NOx P (%) mg/L 1.22 7.46 9.14 1.55 8.99 ---- 10.58 2.09 8.96 9.02 2.38 9.23 7.69 2.58 9.28 7.40 2.76 9.44 8.30 2.86 9.21 8.46 3.12 9.97 8.53 3.30 9.87 10.68 3.52 9.38 8.48 NH3 Percent N mg/L (X) N/D 5.53 N/D 6.02 N/D 5.81 N/D 6.26 N/D 6.09 N/D 6.05 N/D 5.68 N/D 5.58 N/D 5.68 N/D 5.63 Maximum 1.92 3.52 10.68 N/D 6.26 Mean 0.52 2.54 9.00 N/D 5.83 Minimum 0.01 1.22 7.40 N/D 5.53 Std. Dev. 0.59 0.71 0.88 N/D 0.24 Note: N/D - Not Detectable Less than lowest standard 0.05 mg/L BIO-P #1 Feb/19/91-Mar/30/91 FEED pH/Atkatinity/Carbon Day of Run Date pH Alk. Diss. mg/L Oxygen as mg/L CaCOj 33:30pm 1 Feb/19/91 7.49 320 2 3 4 5 6 7 8 9 10 /20/ /21/ mi /23/ 7.34 /24/ /25/ /26/ /27/ 7.37 /28/ Maximum Mean Minimum Std. Dev. 298 222 11 Mar/01/91 12 /02/ 13 /03/ 7.56 228 14 /04/ 15 /05/ 16 /06/ 17 /07/ 7.18 206 18 /08/ 19 /09/ 20 /10/ 21 /11/ 7.13 164 22 /12/ 23 /13/ 24 /14/ 25 /15/ 7.27 278 26 /16/ 27 /17/ 28 /18/ 29 /19/ 7.50 248 30 /20/ 31 /21/ 32 /22/ 33 /23/ 6.81 186 34 /24/ 35 /25/ 36 /26/ 37 /27/ 7.15 224 38 /28/ 39 /29/ 40 /30/ 7.56 320 7.28 237 6.81 164 0.21 47 FEED FEED FEED FEED TC mg/L 108 103 IC TOC mg/L mg/L COO mg/L FT RCTR pH/Alkalinity/Carbon pH Alk. Diss. RCTR RCTR RCTR RCTR mg/L Oxygen EFFL EFFL EFFL EFFL as mg/L TC IC TOC COD CaCO, 33:30pm mg/L mg/L mg/L mg/L 66 42 131 61 42 7.16 270 0.70 0.80 7.02 284 6.40 55 63 46 52 11 29 82 90 92 97 114 98 89 79 114 95 79 11 44 42 44 49 54 48 43 31 66 48 31 10 38 48 48 48 60 50 46 48 60 47 38 6 118 141 -- 155 155 147 151 155 143 118 13 7.37 7.12 6.90 7.37 7.03 7.28 6.84 7.13 7.37 7.12 6.84 0.18 288 192 212 260 266 310 222 250 310 254 192 37 5.50 6.90 7.00 7.00 7.00 4.70 4.10 5.30 1.10 6.50 3.30 5.60 5.50 6.80 5.20 6.50 4.00 6.00 1.45 2.60 5.50 1.80 3.30 7.00 4.60 0.70 2.07 58 32 31 34 46 54 44 42 63 45 31 11 48 25 25 27 39 46 36 35 52 37 25 10 10 7 6 7 7 8 8 8 11 8 6 1 27 29 -- 28 28 20 28 29 27 20 3 BIO- Day of Run 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 P #1 Fet Date Feb/19/91 /20/ mi 1221 1231 /24/ /25/ /26/ /27/ /28/ Mar/01/91 /02/ /03/ /04/ /05/ /06/ /07/ /08/ /09/ /10/ /11/ /12/ /13/ /14/ /15/ /16/ /17/ /18/ /19/ /20/ /21/ /22/ /23/ /24/ /25/ /26/ mi 1281 1291 1301 Maximum Mean Minimum Std. Dev. /19/91 pH 7.10 7.08 7.32 7.05 6.97 7.38 7.06 7.34 7.02 7.21 7.38 7.15 6.97 0.14 -Mar/30/91 RT Alk. Diss. mg/L as CaCOj 252 282 290 178 220 258 268 312 232 242 312 253 178 36 Oxygen mg/L 33:30pm 0.70 0.80 5.40 0.70 1.00 6.50 6.40 6.00 0.80 4.70 2.70 1.00 6.90 0.70 0.80 4.20 6.90 0.80 5.10 0.90 5.80 1.00 1.10 1.50 1.50 1.60 ---- 6.90 2.90 0.70 2.37 RCTR RCTR EFFL TC mg/L 53 63 56 34 31 36 47 52 44 37 63 45 31 10 pH/Alkalinity, RCTR RCTR EFFL IC mg/L 44 53 47 28 25 30 39 45 38 30 53 38 25 9 EFFL TOC mg/L 9 10 9 6 6 6 8 7 6 7 10 7 6 1 'Carbon RCTR EFFL COD mg/L 27 -- 15 27 -- -- 28 28 28 24 28 25 15 4 Day of Run 1 2 3 4 5 6 7 3 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 Date Apr/22/91 122,1 nu /25/ /26/ mi mi /29/ /30/ May/01/91 /02/ /03/ /04/ /05/ 1061 1071 1081 1091 noi mi Ml IMI /14/ /15/ 1161 mi 1181 1191 1201 121/ 1221 /23/ /24/ 1251 1261 1271 128/ 1291 1301 /31/ Maximum Mean Minimum Std. Dev. pH 7.54 7.29 7.11 7.43 7.39 7.59 7.43 7.47 7.43 7.09 7.59 7.38 7.09 0.16 Alk. mg/L as CaCO, 360 276 220 210 212 268 264 292 312 232 360 265 210 46 FEED pH/Alkalin BIO-P #2 ity/Carboi Diss. FEED FEED Oxygen mg/L TC IC 33:30pm mg/L mg/L 129 101 93 74 75 92 82 97 102 85 129 93 74 15 79 54 43 42 43 59 54 63 68 51 79 56 42 11 Apr/22/91-May/31/91 l 1 FEED FEED pH TOC COD mg/L mg/L 50 72 7.80 47 66 7.86 5C 32 32 33 28 34 34 34 50 37 28 8 71 7.58 44 7.56 47 7.49 42 7.51 44 7.51 50 7.11 46 7.48 49 7.46 72 7.86 53 7.54 42 7.11 11 0.19 :T RCTR Atk. mg/L as CaCOj 392 352 310 196 220 172 296 240 290 306 392 277 172 66 pH/Alk Diss. Oxygen mg/L 33:30pm 6.90 7.30 8.00 - 5.90 6.30 1.20 6.00 7.30 7.20 7.80 6.80 7.10 6.70 7.10 7.40 7.00 6.60 7.20 6.30 6.80 8.00 6.65 1.20 1.36 alinity/Carbon RCTR EFFL TC mg/L 78 70 49 41 38 40 59 53 59 63 78 55 38 13 RCTR EFFL IC mg/L 64 61 40 33 31 31 53 47 52 55 64 47 31 12 RCTR EFFL TOC mg/L 14 9 9 8 7 9 6 6 7 8 14 8 6 2 RCTR EFFL COD mg/L 20 12 14 10 12 14 12 11 11 12 20 13 10 3 BIO- Day of Run 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 P #2 Apr Date Apr/22/91 /23/ /24/ /25/ /26/ mi /28/ /29/ /30/ May/01/91 /02/ /03/ /04/ /05/ /06/ /07/ /08/ /09/ /10/ /1V /12/ /13/ /14/ /15/ /16/ /17/ /18/ /19/ /20/ /21/ /22/ 1231 /24/ /25/ /26/ mi 1281 1291 /30/ /31/ Maximum Mean Minimum Std. Dev. /22/91-May/31/91 RT pH Alk. Diss. 7.86 7.97 7.69 7.92 7.61 7.57 7.61 7.34 7.50 7.49 7.97 7.66 7.34 0.19 mg/L as CaCOL 390 343 330 200 218 170 290 230 306 340 390 282 170 69 Oxygen mg/L 33:30pm 8.00 7.80 8.00 7.60 7.90 4.20 7.60 7.90 7.50 7.80 6.60 7.20 6.80 7.30 7.60 7.20 7.00 6.30 7.30 7.50 .... 8.00 7.26 4.20 0.84 RCTR RCTR EFFL TC mg/L 78 75 56 41 35 40 60 51 58 61 78 56 35 14 pH/Alkalinityj RCTR RCTR EFFL IC mg/L 65 66 45 33 28 32 53 45 51 53 66 47 28 13 EFFL TOC mg/L 13 9 11 8 7 8 7 6 7 8 13 8 6 2 'Carbon RCTR EFFL COO mg/L 18 4 14 10 10 12 14 9 11 11 18 11 4 3 Carbon Decay in Cold Room Raw Influent Sewage Day COD TC TIC TOC 1 2 3 4 5 6 7 8 10 11 12 13 14 15 16 128 137 120 110 110 110 101 82 73 92 64 64 73 55 46 62.4 60.4 56.8 55.1 56.1 52.8 52.3 45.0 49.9 46.9 49.7 46.7 43.2 44.6 44.7 21.2 21.4 22.0 20.8 22.9 22.2 22.4 19.4 23.0 21.3 26.0 24.7 23.3 25.2 25.0 41.2 39.0 34.8 34.3 33.2 30.6 29.9 25.6 26.9 25.7 23.7 22.0 19.9 19.4 19.7 Carbon Decay in Feed Bucket Raw Influent Sewage Day COD TC TIC TOC 1 2 3 4 110 70 64 64 62.5 54.1 48.1 46.6 21.5 21.8 21.3 21.2 41.0 32.3 26.8 25.4

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