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Biological nitrification and denitrification of high ammonia landfill leachate using pre denitrification… Shiskowski, Dean Micheal 1995

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BIOLOGICAL NITRIFICATION AND DENITRIFICATION OF HIGH AMMONIA LANDFILL LEACHATE USING PRE DENITRIFICATION AND PRE/POST DENITRD7ICATION PROCESSES  by Dean Micheal Shiskowski Dipl. (Environmental and Water Resources Engineering Technology) Saskatchewan Institute of Applied Science and Technology, 1988 B.A.Sc. (Regional Environmental Systems Engineering) University of Regina, 1993  A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF APPLIED SCIENCE 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 September, 1995 © Dean M . Shiskowski, 1995  In  presenting this  degree at the  thesis in  University of  partial  fulfilment  of  of  department  this thesis for or  by  his  or  scholarly purposes may be granted her  representatives.  permission.  Department The University of British Columbia Vancouver, Canada  for  an advanced  Library shall make it  agree that permission for extensive  It  publication of this thesis for financial gain shall not  DE-6 (2/88)  requirements  British Columbia, I agree that the  freely available for reference and study. I further copying  the  is  by the  understood  that  head of my copying  or  be allowed without my written  ABSTRACT  The purpose of this research was to investigate the nitrogen removal capabilities of two different biological process configurations treating high strength leachate containing up to 1200 mg N/1 of ammonia.  The first configuration was a predenitrification system known as the Modified Ludzack-  Ettinger (MLE) process. The MLE Startup Phase consisted of starting up two MLE systems treating "base" leachate containing about 230 mg N/1 of ammonia, followed by incrementally increasing leachate ammonia concentrations to a "target" level of 1200 mg N/1. Aerobic SRT's were maintained at 13 days during the MLE Startup Phase. Increases in clarifier sludge recycle flows to yield recycle ratios of 7:1 (System 1) and 8:1 (System 2), from 6:1, were investigated as a means to reduce effluent NOx concentrations during the MLE Recycle Phase. An aerobic SRT of 10 days was initially used in both systems during the MLE Recycle Phase. A pre and postdenitrification system, known as the Bardenpho process, was the second configuration evaluated. The Bardenpho Phase examined the overall nitrogen removal capabilities of this process when treating leachate containing about 1100 mg N/1 of ammonia.  Both MLE systems experienced nitrification failure during the initial attempt to reach the "target" leachate ammonia concentration of 1200 mg N/1 (MLE Startup Phase).  Anoxic methanol loadings were  maintained at levels required for denitrifying the "base" leachate (i.e. 230 mg N/1). Rapid accumulation of ammonia in the systems, due to small amounts of anoxic ammonia assimilation caused by limited denitrification, apparently resulted in "free" ammonia toxicity of Nitrosomonas bacteria. Attempts to assimilate excess ammonia by increasing anoxic methanol loadings resulted in raising reactor pH levels, due to increased denitrification, and a further rise in "free" ammonia concentrations. Anoxic methanol loadings were increased simultaneously with leachate ammonia concentrations during the second attempt to reach the "target" ammonia concentration.  Nitrification, and denitrification, was successfully  established in both systems using this procedure.  Increases in clarifier sludge recycle ratios (MLE Recycle Phase), with corresponding decreases in reactor actual hydraulic retentiontimes,resulted in the rapid rise of reactor and effluent ammonia concentrations ii  A  in both systems. Increases in aerobic SRT from 10 days to 20 days resulted in larger reactor solids levels and a reduction in effluent ammonia concentrations to around 50 mg N/1. Decreases in leachate ammonia concentration of about 80 mg N/1 resulted in effluent ammonia values of around 15 mg N/1. A total reduction in leachate ammonia concentration of about 200 mg N/1 did not further reduce effluent ammonia levels. Complete and consistent anoxic denitrification was achieved in both systems regardless of recycle ratio.  Anoxic methanol loadings of about 2.8 mg COD/mg NOx-N resulted in 100% anoxic NOx  removal. Aerobic NO2/NOX ratios were about 0.60 in both systems. System 2 (r = 8:1) had significantly larger reactor solids levels than System 1 (r = 7:1) with slightly lower effluent total inorganic nitrogen (ammonia + NOx) concentrations (170 mg N/l versus 190 mg N/1). However, both systems had effluent total inorganic nitrogen concentrations of less than 160 mg N/l, when operating with recycle ratios of 6:1. Hence, increased total inorganic nitrogen removal was not realized when using larger recycle ratios.  The Bardenpho System was capable of producing effluent containing less than 1 mg N/l of ammonia and 15 mg N/l of NOx, when treating 1100 mg N/l ammonia leachate. An Aerobic #1 SRT of 20 days was used with Aerobic #1 and clarifier sludge recycle ratios of 4:1 and 3:1, respectively. Residual effluent NOx was caused by incomplete ammonia removal in the first aerobic reactor and the production of NOx in the second aerobic reactor. However, approximately 5 mg N/l of ammonia was assimilated in the second anoxic reactor, thus indicating the need for a small amount of ammonia to remain in the mixed liquor so as to not limit denitrification. Anoxic methanol loadings of about 3.7 to 3.8 mg COD/mg NOxN resulted in 100% anoxic NOx removal. Aerobic #1 NO2/NOX ratios were about 0.60, with Aerobic #2 ratios < 0.09.  The clarifier sludge recycle ratio had to be increased from 2:1 to 3:1, to prevent the  accumulation of solids in the clarifier.  111  TABLE OF CONTENTS  ABSTRACT  ii  TABLE OF CONTENTS  iv  LIST OF TABLES  viii  LIST OF FIGURES  ix  ACKNOWLEDGEMENTS  xiii  INTRODUCTION  1  1.1  Leachate Generation and Quality  1  1.2  Environmental Impacts of Nitrogenous Wastes  4  1.3  Nitrogen Removal Methods  5  1.3.1  Physical-Chemical Methods  5  1.3.2  Biological Assimilation of Ammonia  5  1.3.3  Biological Nitrification and Denitrification  6  1.3.3.1 Nitrification  6  1.3.3.2 Denitrification  6  1.4  Treatment Method and Process Configurations  7  1.5  Study Rationale and Objectives  10  LITERATURE REVIEW 2.1  .  13  UBC Leachate Treatment  13  2.1.1  Heavy Metal Inhibition  13  2.1.2  External Carbon Sources for Denitrification  14  iv  2.1.3  Cold Temperature Performance  15  2.1.4  Hydraulic Retention Time/Sludge Recycle Effects  15  2.1.5  Increased Leachate Ammonia Levels  16  2.2  Hydraulic Studies  16  2.3  Reactor Configuration  18  2.4  Nitrification Inhibition  18  EXPERIMENTAL SETUP AND OPERATION  21  3.1  MLE System Design  21  3.2  Bardenpho System Design  22  3.3  Leachate Feed  22  3.4  Chemical Addition  23  3.5  MLE System Startup and Operation  24  3.6  Bardenpho System Startup and Operation  26  ANALYTICAL METHODS  27  4.1  Ammonia (NH + NH +)  27  4.2  Nitrate plus Nitrite (NOx)  28  4.3  Nitrite (N0 -)  28  4.4  Orthophosphate (Ortho-P)  28  4.5  Solids (TSS and VSS)  29  4.6  Biochemical Oxygen Demand (BOD5)  29  4.7  Chemical Oxygen Demand (COD)  29  4.8  Alkalinity (as CaC03/L)  30  4.9  pH  30  4.10  Oxidation-Reduction Potential (ORP)  30  4.11  Dissolved Oxygen (DO)  31  4.12  Temperature  31  3  4  2  v  RESULTS AND DISCUSSION 5.1  5.2  5.3  32  MLE Startup Phase  33  5.1.1  Incremental Ammonia Loading and Nitrification Failure  34  5.1.2  Nitrification Recovery  45  5.1.3  Second Attempt at Incremental Ammonia Loading  46  5.1.4  Possible Explanations for Nitrification Failure  47  MLE Recycle Phase  62  5.2.1  Ammonia Levels - SRT Effects  63  5.2.2  Reactor Solids Levels - SRT Effects  70  5.2.3  Ammonia Levels - Ammonia Mass Loading Effects  74  5.2.4  Reactor Solids Levels - Ammonia Mass Loading Effects  75  5.2.5  Effluent Solids Levels  75  5.2.6  Ammonia Removal  78  5.2.7  Nitrification  83  5.2.8  NOx Levels  88  5.2.9  Denitrification  94  5.2.10 System NOx Removal  99  Bardenpho Phase  101  5.3.1  System Operation  102  5.3.2  Solids Levels  103  5.3.3  Ammonia Levels and Removal  105  5.3.4  Nitrification  111  5.3.5  NOx Level s and Removal  113  5.3.6  Denitrification  116  5.3.7  pH Levels  120  SUMMARY, CONCLUSIONS AND RECOMMENDATIONS 6.1  Summary  *  125 125  vi  6.1.1  MLE Startup Phase  125  6.1.2  MLE Recycle Phase  126  6.1.3  Bardenpho Phase  128  6.2  Conclusions  129  6.2  Recommendations  130  REFERENCES  132  APPENDIX A Calculation Definitions  136  APPENDIX B Raw and Calculated Data  145  APPENDIX C Statistical Analyses  228  vii  LIST O F T A B L E S  Table 3.1  Burns Bog Leachate Composition  23  Table 5.1  Reactor Alkalinity Data  45  Table 5.2  "Free" Ammonia Fraction at Various pH Values  56  Table 5.3  MLE Reactor Actual Hydraulic Retention Times  63  Table 5.4  Aerobic "Free" Ammonia Concentrations  69  Table 5.5  Anoxic "Free" Ammonia Concentrations  69  Table 5.6  Bardenpho Reactor Actual Hydraulic Retention Times  102  viii  LIST O F FIGURES  Figure 1.1  MLE Process Configuration  Figure 1.2  Bardenpho Process Configuration  Figure 5.1  MLE Startup Phase - System # 1 Simulated Leachate Ammonia Values  Figure 5.2  MLE Startup Phase - System #2 Simulated Leachate Ammonia Values  Figure 5.3  MLE Startup Phase - System #1 Anoxic and Aerobic Ammonia Values  Figure 5.4  MLE Startup Phase - System #2 Anoxic and Aerobic Ammonia Values  Figure 5.5  MLE Startup Phase - System #1 Anoxic Methanol Loading  Figure 5.6  MLE Startup Phase - System #2 Anoxic Methanol Loading  Figure 5.7  MLE Startup Phase - System #1 Anoxic and Aerobic pH Values  Figure 5.8  MLE Startup Phase - System #2 Anoxic and Aerobic pH Values  Figure 5.9  MLE Startup Phase - System #1 Anoxic and Aerobic VSS Values  Figure 5.10  MLE Startup Phase - System #2 Anoxic and Aerobic VSS Values  Figure 5.11  MLE Startup Phase - System #1 Anoxic % Ammonia Removal and Methanol Loading  ix  Figure 5.12  MLE Startup Phase - System #2 Anoxic % Ammonia Removal and Methanol Loading  Figure 5.13  MLE Startup Phase - System # 1 Anoxic Ammonia Removal Rate and Methanol Loading  Figure 5.14  MLE Startup Phase - System #2 Anoxic Ammonia Removal Rate and Methanol Loading  Figure 5.15  MLE Startup Phase - System #1 Anoxic and Aerobic Free Ammonia Values  Figure 5.16  MLE Startup Phase - System #2 Anoxic and Aerobic Free Ammonia Values  Figure 5.17  MLE Startup Phase - System #1 Anoxic and Aerobic NOx Values  Figure 5.18  MLE Startup Phase - System #2 Anoxic and Aerobic NOx Values  Figure 5.19  MLE Recycle Phase - System # 1 (r = 7:1) Anoxic and Aerobic Ammonia Values  Figure 5.20  MLE Recycle Phase - System #2 (r = 8:1) Anoxic and Aerobic Ammonia Values  Figure 5.21  MLE Recycle Phase - System #1 (r = 7:1) Anoxic and Aerobic pH Values  Figure 5.22  , MLE Recycle Phase - System #2 (r = 8:1) Anoxic and Aerobic pH Values  Figure 5.23  MLE Recycle Phase - System #1. (r = 7:1) Anoxic and Aerobic VSS Values  Figure 5.24  MLE Recycle Phase - System #2 (r = 8:1) Anoxic and Aerobic VSS Values  Figure 5.25  MLE Recycle Phase - System #1 (r = 7:1) Effluent SS Values  Figure 5.26  MLE Recycle Phase - System #2 (r = 8:1) Effluent SS Values  Figure 5.27  MLE Recycle Phase - System #1 (r = 7:1) Anoxic, Aerobic and System % Ammonia Removal i  Figure 5.28  MLE Recycle Phase - System #2 (r = 8:1) Anoxic, Aerobic and System % Ammonia Removal  Figure 5.29  MLE Recycle Phase - System #1 (r = 7:1) % Nitrification and Specific Nitrification Rate  Figure 5.30  MLE Recycle Phase - System #2 (r = 8:1) % Nitrification and Specific Nitrification Rate  Figure 5.31  MLE Recycle Phase - System #1 (r = 7:1) Anoxic and Aerobic NOx Values  Figure 5.32  MLE Recycle Phase - System #2 (r = 8:1) Anoxic and Aerobic NOx Values  Figure 5.33  MLE Recycle Phase - System #1 (r = 7:1) Anoxic and Aerobic NO2 Values  Figure 5.34  MLE Recycle Phase - System #2 (r = 8:1) Anoxic and Aerobic NO2 Values  Figure 5,35  MLE Recycle Phase - System #1 (r = 7:1) % Denitrification and Specific Denitrification Rate  Figure 5.36  MLE Recycle Phase - System #2 (r = 8:1.) % Denitrification and Specific Denitrification Rate  Figure 5.37  Bardenpho System Anoxic and Aerobic VSS Values  Figure 5.38  Bardenpho System Effluent TSS and VSS Values  Figure 5.39  Bardenpho System Anoxic and Aerobic Ammonia Values xi  Figure 5.40  Bardenpho System Anoxic and Aerobic % Ammonia Removal  Figure 5.41  Bardenpho System Anoxic Ammonia Removal  Figure 5.42  Bardenpho System % Nitrification and Alkalinity Consumption  Figure 5.43  Bardenpho System Specific Nitrification Rates  Figure 5.44  Bardenpho System Anoxic and Aerobic NOx Values  Figure 5.45  Bardenpho System Anoxic and Aerobic NO2 Values  Figure 5.46  Bardenpho System % Denitrification  Figure 5.47  Bardenpho System Specific Denitrification Rates  Figure 5.48  Bardenpho System Anoxic NOx Loads  Figure 5.49  Bardenpho System Anoxic and Aerobic pH Values  xii  AC KNOWLEDGEMENTS  I would like to thank Dr. D.S. Mavinic for his technical expertise, patience and personal encouragement throughout the course of this study, and in particular, when I called his home on weekends seeking advice. In addition, I would also like to thank Jufang Zhou, Paula Parkinson and Susan Harper of the U.B.C. Environmental Engineering Laboratory for answering an endless stream of questions, analyzing samples at sometimes the most awkward of times, and providing an enjoyable working environment. Their assistance made this study possible.  I also want to thank Guy Kirsh and Ron Dolling of the U.B.C. Civil  Engineering Workshop for their assistance related to lab equipment and ensuring a safe experimental apparatus.  I would also like to thank Barry Azevedo, a former environmental engineering graduate student, for his suggestions regarding my research; and Paul Henderson from the City of Vancouver and the staff at the Bums Bog Landfill for arranging for me to collect leachate used in this study.  Finally, I would like to thank the Natural Sciences and Engineering Research Council of Canada (NSERC) for providing financial assistance to me in the form of a Postgraduate Scholarship.  xiii  Chapter 1 INTRODUCTION  Landfilling of municipal solid waste (MSW) is the most economical and commonly used method of waste disposal (Henry and Heinke 1989). North America and the United Kingdom landfill 90% of their MSW that is sent for disposal . In Europe, although significant investments have been made in incineration and composting plants, over 60% of MSW is still landfilled.  Modem landfill design and operation have significantly reduced the environmental contamination potential of this method of waste disposal. Landfill gas is often collected and used for energy production. Highly contaminated liquid waste, called leachate, is also collected to prevent escape into the surrounding environment. However, due to the nature of leachate, it cannot be safely discharged into the environment withoutfirstreceiving some form of treatment.  The following sections discuss leachate generation within landfills and mechanisms controlling leachate quality, and the need for leachate treatment. The purpose of this research was leachate treatment; thus, various leachate treatment methods, as well as the method and process configurations used in this study, and study objectives are also presented.  1.1  Leachate Generation and Quality  The downward movement of water through a landfill "leaches" contaminants derived from the waste and ultimately results in the production of leachate. Rainfall provides the major transport phase for the actual leaching of contaminants out of the landfill and also provides the required moisture for biological activity within the landfill (Pohland et al 1985). The dissolution of contaminants from the waste and into the infiltrating water is largely controlled by the biological reactions occurring inside the landfill. Pohland et al (1985) has described five distinct phases that occur during the "life" of a landfill. These phases are discussed below.  1  The first phase, Initial Adjustment, occurs when waste is initially placed into the landfill, settlement occurs, and each area, or "cell", of the landfill is closed.  Infiltrahon of precipitation eventually causes the field capacity of the waste to be exceeded, therefore, leachate is produced. The second, or Transition, phase is characterized by a change from aerobic to facultative and anaerobic conditions, as oxygen is replaced by nitrates and sulfates as the electron acceptor.  Breakdown of organic waste material by acetogenic bacteria results in the production of  intermediate organic volatile fatty acids (VFA's), therefore, the biochemical oxygen demand (BOD) of the leachate begins to rise.  Continued formation and domination of VFA's occurs during the third phase, Acid Formation. The presence of VFA's results in a drop in pH and causes the dissolution and complexation of metal species. Phosphorus is released and utilized by bacteria. Organically bound nitrogen, contained within amino groups (NH2) of proteins (Tortora et al 1989), is converted into ammonia nitrogen (NH3) by saprophytic bacteria (Sawyer and McCarty 1978). Some of the ammonia is utilized by bacteria as a nutrient with the remainder appearing in the leachate.  The intermediate VFA's produced in the previous phases are converted to methane and carbon dioxide by methanogenic bacteria during the fourth phase, Methane Fermentation. pH levelsrise,with the concurrent precipitation of metals, as the buffer system within the landfill returns to that of the bicarbonate system rather than the previous system controlled by VFA's. Low oxidation-reduction potentials (ORP) result in the reduction of oxidized species. Leachate BOD levels decrease significantly as VFA's are converted to methane; however, high ammonia concentrations remain.  Final Maturation, phase five, is characterized by "relative dormancy" due to the absence of readily degradable organic matter. Gas production ceases, and oxygen and oxidized species may reappear with a corresponding increase in ORP. Slow degradation of more biologically resistant organic materials may produce hurnic-like substances capable of complexing and redissolving metals. 2  The terms "young" and "old" are often used to describe landfill age. A "young" landfill is one that is still in the Acid Formation phase.  Leachate from such a landfill is characterized by very high BOD  concentrations, due to the production of VFA's, and high ammonia concentrations (Robinson et al 1992). An "old" landfill, described as being in the Methanogenic phase, still produces leachate containing high ammonia levels; however, BOD concentrations are much lower due to the conversion of VFA's to methane and carbon dioxide.  United Kingdom landfills in the "young" Acid Formation phase were found to have mean BOD5 and ammonia values of about 19,000 mg/L and 900 mg N/L, respectively (Robinson and Gronow 1993). Similarly, "old" Methanogenic landfills had mean BOD5 and ammonia concentrations of about 375 mg/L and 900 mg N/L, respectively. The same study found that over 50% of landfills surveyed in the United Kingdom reached the Methanogenic phase within 3 years of waste placement; over 90% were in the Methanogenic phase after 10 years. The Tseung Kwan O Landfill in Japan, also in the Methanogenic phase, has ammonia and BOD5 concentrations of about 2000 mg N/L and 200 mg/L, respectively (SENT 1992). The Burns Bog Landfill in Delta, British Columbia produces leachate containing about 200 mg N/L of ammonia and less than about 50 mg/L of BOD5 (Carley and Mavinic 1991, Manoharan et al 1992, Azevedo 1993).  Biodegradable organic compounds and ammonia are the leachate constituents that pose the most significant environmental threats (Azevedo 1993). As discussed above, leachate from "older" landfills contains little BOD; therefore, ammonia levels in such leachate is the most important in terms of environmental impacts and treatment objectives (Robinson et al 1992). The research conducted for this study utilized an "old" leachate containing high ammonia and low carbon concentrations.  Therefore,  carbon (i.e. BOD) removal will not be further discussed, except as it pertains to biological nitrogen removal.  3  1.2  Environmental Impacts of Nitrogenous Wastes  The United States Environmental Protection Agency (EPA 1993) provides an excellent overview regarding the effects of nitrogen discharges into the environment and includes: eutrophication of surface waters, depletion of surface water dissolved oxygen (DO) levels by nitrification, ammonia toxicity of aquatic organisms, and public health concerns.  The following is a brief summary of information  contained in the aforementioned report.  Eutrophication is defined as excessive plant and/or algae "bloom" growth in rivers, lakes and estuaries. Nitrogen, along with phosphorus, carbon dioxide and light, is required for growth by plants and algae. Nitrogen is often unavailable in sufficient quantities, particularily in marine waters, to promote growth (i.e. growth limiting); therefore, the addition of nitrogen to surface waters via waste discharges can trigger the excessive growth of plants and/or algae. Effects of eutrophication include poor aesthetic appearance of water, odour problems, and lowering of DO levels due to decomposition of plant material. Respiration of aquatic organisms (e.g. fish, benthic animals) can be affected by reduced DO concentrations.  Water DO levels can be further lowered during nitrification of wastes containing ammonia by biological oxidation of ammonia to nitrite and nitrate.  Ammonia toxicity of aquatic organisms is caused by unionized "free" ammonia (NH3). "Free" ammonia exists in equilibrium with the ammonium ion (NH4 ). +  pH and temperature are the main factors  controlling the equilibrium. Thefractionof "free" ammonia, relative to "total" ammonia, increases with increases in both pH and temperature. "Free" ammonia concentrations of between 0.1 and 10 mg/L have been found to be acutely toxic tofreshand saltwater fish species.  Public health effects associated with nitrogen are specifically related to nitrates (NO3") and nitrites (NO2" ). Infant methemoglobinemia (i.e. "blue babies") is caused by the reduction of nitrate to nitrite in the stomach followed by nitrite oxidation of iron within hemoglobin molecules. The altered hemoglobin (methemoglobin) cannot exchange oxygen; therefore, suffocation of the victim can occur if not treated. In  addition, nitrites can also react with amines and amides to form N-nitroso compounds. These compounds have been found to be carcinogenic.  1.3  Nitrogen Removal Methods  1.3.1  Physical-Chemical Methods  Forgie (1988b) identifies air stripping as a potential method for ammonia removalfromleachate. Lee and Naimie (1985) found that up to 70% of the ammonia could be strippedfroma waste in an aerated reactor with a hydraulic retention time of 4 days and an initial pH of 10.0. The waste initially contained 300 mg/L of ammonia. However, air stripping of ammonia is costly because of the need for high pH levels (i.e. addition of basic solutions) and large aeration volumes.  In addition, the process is temperature  sensitive and fogging/icing can occur in cold weather (Metcalf & Eddy 1991).  Ion exchange, using clinoptilolite, can also be used for ammonia removal (Forgie 1988b). High costs for the media, and subsequent regenerations, prohibit using this method except in the case where removal of low concentrations of residual ammonia (e.g. 15 mg/L) is desired.  1.3.2  Bacterial Assimilation of Ammonia  Robinson (1987) treated leachate from a landfill in the U.K., utilizing the concept that aerobic oxidation of carbonaceous matter requires ammonia nitrogen for the synthesis of cellular material. Leachate ammonia concentrations of about 800 mg N/L were reduced to less than 2 mg/L after treatment. The leachate contained insufficient biodegradable organic carbon to result in the assimilation of all the available ammonia (i.e. BOD:N < 100:5); therefore, jam wastefroma local factory was used to supply the additional carbon. High sludge production is a potential disadvantage of this method of ammonia removal.  5  1.3.3  Biological Nitrification and Denitrification  1.3.3.1 Nitrification Nitrification is the aerobic two-step conversion of ammonia (NH4 ) first to nitrite (NO2") and then to +  nitrate (NO3"). Two specific genera of bacteria are responsible for nitrification: Nitrosomonas converts ammonia to nitrite, and Nitrobacter converts nitrite to nitrate. These bacteria are autotrophic organisms; therefore, they derive energy from oxidation of the inorganic compounds ammonia and nitrite.  In  addition, inorganic carbon (i.e. carbon dioxide) is used for cell synthesis rather than organic carbon.  Stoichiometric equations describing combined energy production and cell synthesis for Nitrosomonas and Nitrobacter are as follows (EPA 1993):  Nitrosomonas: 1.00NH + 1.440 + 0.0496CO > O.OIC5H7NO2 + 0.990NO + 0.970H 0 + +  4  _  2  2  2  2  1.99H+ Nitrobacter:  I.OONO2" + 0.00619NH + 0.031C0 + 0.0124H 0 + 0.50O > O.OO6I9C5H7NO2 + +  4  2  2  2  1.00NO - + 0.00619H  +  3  The above equations assume Nitrosomonas and Nitrobacter cell synthesis rates of 0.08 g VSS/g NH4 -N +  and 0.05 g VSS/g NH4 -N, respectively. Cellular composition is assumed to be C5H7NO2. +  The production of hydrogen ions during nitrification results in the destruction of alkalinity to a ratio of 7.1 g CaCC>3 per g NH4 -N nitrified. +  The above equations illustrate that most of the hydrogen ion  production, hence alkalinity destruction, occurs during the ammonia oxidation step.  Total oxygen  consumption for nitrification, also based on stoichiometric requirements, is 4.6 g O2 per g NH4 -N +  nitrified.  1.3.3.2 Denitrification Denitrification is the anoxic conversion of nitrate to nitrite, and then to gaseous nitrogen compounds (e.g. N ) that are released into the atmosphere. Unlike nitrification, denitrification can be accomplished by 2  6  several genera of bacteria including Achromobacter, Aerobacter, Alcaligenes, Bacillus, Brevbacterium, Flavobacterium, Lactobacillus, Micrococcus, Proteus, Pseudomonas, and Spirillum (Metcalf and Eddy 1991). Denitrifying bacteria are heterotrophic organisms; therefore, they require organic carbon for both cell synthesis as well as an electron donor for energy production. These bacteria are also facultative, thus they have the ability to use oxygen, as well as nitrate and nitrite, as electron acceptors during energy production by modifying enzymes in their metabolic systems (EPA 1993). Energy production is most efficient when oxygen is the electron acceptor; hence, the bacteria will preferentially utilize oxygen over nitrate or nitrite. Therefore, the absence of oxygen is important for the reduction of nitrate and nitrite.  Stoichiometric equations, using methanol ( C H 3 O H ) as the organic substrate, describing combined energy production and cell synthesis for the complete reduction of nitrate and nitrite are as follows (EPA 1993):  Nitrate Reduction:  NO3- + 1.08CH3OH + 0.24H CO > 0.056C H NO + 0.47N + 1.68H 0 + 2  3  5  7  2  2  2  HCO3-  Nitrite Reduction:  N 0 " + 0.67CH OH + 0.53H CO > 0 . 0 4 C H N O + 0.48N + 1.23H 0 + 2  3  2  3  5  7  2  2  2  HCO3-  Complete nitrate reduction requires 2.47 g C H 3 O H per g N03"-N (i.e. 3.7 g COD/g N03"-N); complete nitrite reduction requires 1.53 g C H 3 O H per g N 0 ' - N (i.e. 2.3 g COD/g N0 "-N) (Azevedo 1993). 2  2  Hydroxide ions produced during reduction of nitrite react with carbon dioxide in the water to produce bicarbonate ions, therefore, bicarbonate alkalinity (EPA 1993). Alkalinity is generated at the ratio of 3.57 g C a C 0 per g N0 "-N denitrified (EPA 1975). 3  1.4  2  Treatment Method and Process Configurations  Biological nitrification and denitrification was the method selected for treatment of the high ammonia, low carbon landfill leachate used in this study. Several different process configurations have been successfully 7  used to remove ammonia from leachate and other high strength wastes. Extended aeration lagoons, operated in sequencing mode, have been used to nitrify leachate containing in excess of 1000 mg N/L of ammonia (Robinson et al 1992). Knox (1985) used a suspended growth, activated sludge system and an attached growth biological filter to nitrify leachate containing up to 500 mg N/L of ammonia. Peddie and Atwater (1985) used a rotating biological contactor to treat leachate containing ammonia levels of up to 50 mg N/L. A sequencing batch reactor, activated sludge system was used by Hosomi et al (1989) to nitrify and denitrify leachate containing about 200 mg N/L of ammonia. Similarly, Bortone et al (1992) used sequencing batch reactors to nitrify/denitrify piggery waste containing over 800 mg N/L of ammonia.  Two different complete mix, suspended growth, single sludge, activated sludge process configurations were selected for this study. The first was a predenitrification system known as the Modified LudzackEttinger (MLE) process (Figure 1.1). As discussed later in Chapter 2, research has shown this process to be suitable for treating high ammonia leachates and other wastes. Leachate enters the anoxic reactor and is diluted by sludge returned from the clarifier. The mixed liquor then flows into the aerobic reactor where nitrifiying bacteria oxidize ammonia to nitrite and nitrate (i.e. NOx) (Ludzack and Ettinger 1962). Nitrified, settled sludge from the clarifier is returned to the anoxic reactor where denitrifiying bacteria reduce NOx to gaseous nitrogen compounds (e.g. N ) that are "released" into the atmosphere. 2  The "predenitrification" and single sludge component of the MLE process offers several advantages over other activated sludge systems (Argaman 1982): dilution of incoming leachate, ability to use organic carbon present in leachate to denitrify return nitrified mixed liquor/sludge, removal of organic carbon in anoxic reactor minimizes oxidation in aerobic reactor, (thus reducing oxygen requirements), reduced alkalinity consumption minimizes chemicals needed for pH control, and the need for only one clarifier versus multiple clarifiers required for separate stage (i.e. multiple sludge) nitrification and denitrification.  The most significant shortcoming of "predenitrification only" systems, such as the MLE process, is effluent concentrations of oxidized nitrogen compounds (NOx) can remain high because not all of the nitrified sludge can be returned to the anoxic reactor for denitrification. Effluent NOx levels can be 8  9  roughly estimated by dividing leachate ammonia concentrations by the sum of the leachate flow plus clarifier sludge recycle flow.  Increases in clarifier sludge recycle flow, in theory, result in decreased  effluent NOx concentrations. Other disadvantages include very high mass solids loading on the clarifier and high power costs associated with large recycle flows.  A pre and postdenitrification system, known as the Bardenpho process (EPA 1993), was the second process configuration examined (Figure 1.2) in this study.  The "predenitrification" section of the  Bardenpho system is similar to that of the MLE process. However, the source of NOx for denitrification in Anoxic #1 is the "aerated" mixed liquor returned from Aerobic #1 rather than "anoxic" clarifier sludge. The "postdenitrification" section allows for denitrification of NOx that is not returned to Anoxic #1; therefore, effluent from the Bardenpho system can be essentially free of NOx. The disadvantage of such a system, obviously, is the extra reactors and associated related costs.  1.5  Study Rationale and Objectives  The rationale for the present study was based on previous research conducted by Azevedo (1993) and Elefsiniotis et al (1989). Rising ammonia concentrations in leachate from landfills around the world prompted Azevedo (1993) to determine maximum leachate ammonia concentrations that could be successfully nitrified and denitrified using MLE systems.  Results indicated that leachate ammonia  concentrations of up to 1500 mg N/L could be treated to produce effluent containing < 1 mg N/L of ammonia. However, an excessive amount of NOx (i.e. 170 mg N/L) remained in the effluents due to the magnitude of the clarifier sludge recycle flow.  Elefsiniotis et al (1989) attempted to reduce NOx  concentrations in effluent from MLE systems treating leachate, containing about 240 mg N/L of ammonia, by increasing clarifier sludge recycle flows.  Effluent NOx and suspended solids concentrations were  found to increase when clarifier sludge recycle flows were greater than sixtimesthe leachate flow.  The purpose of this study was to investigate ways of reducing effluent NOx concentrations when treating high strength leachate containing up to 1200 mg N/L of ammonia. More specifically, the objectives of the study were: 10  1.  Determine the effects of increasing clarifier sludge recycle flows in predenitrification MLE systems with respect to maximizing ammonia and NOx removal;  2.  Investigate methods to mitigate against process instability when clarifier sludge recycle flows were increased in 1.; and  3.  Based on limitations of the MLE systems as determined in 1. and 2., evaluate the nitrogen removal capabilities of a pre and postdenitrification Bardenpho system.  12  Chapter 2 LITERATURE REVIEW  This chapter presents a brief summary of literature related to nitrogen removal by biological nitrification and denitrification. Emphasis is placed on research utilizing continuous flow, suspended growth activated sludge systems treating high ammonia landfill leachates and industrial wastes.  2.1  U B C Leachate Treatment  This section summarizes extensive research regarding treatment of leachate using the Modified LudzackEttinger (MLE) process that has been conducted at the University of British Columbia (UBC). Ammonia concentrations of approximately 200 mg N/L and biodegradable organic levels of under 50 mg O2/L, as BOD5, were typical of leachates used in the following studies.  2.1.1  Heavy Metal Inhibition  The effects of heavy metals on nitrification and denitrification of leachate were first investigated following inconsistent results obtained by Jasper et al (1985) and Dedhar and Mavinic (1985). Jasper et al (1985) found unstable ammonia removal when treating leachate containing a mean ammonia concentration of 160 mg N/L, using MLE systems with aerobic SRTs of up to 20 days. Mean % nitrification values varied from 7% to 45%.  However,  % denitrification values of over 90% were consistently attained once  operational conditions were optimized. A study conducted by Dedhar and Mavinic (1985), using similar systems and leachate from the same landfill, found reliable ammonia removal (i.e. 100%) from leachate containing up to 288 mg N/L of ammonia. The only discernible difference between the two studies was the leachate used in the first study contained higher concentrations of zinc and manganese than leachate used in the second study.  Manoharan et al (1992) then investigated the effects of zinc, chromium, nickel, and manganese on nitrification and denitrification of leachate.  The addition of zinc to leachate resulted in nitrification  inhibition. However, increases in phosphorus addition to the systems resulted in nitrification recovery. 13  The lack of biologically available phosphorus, due to coprecipitation of zinc phosphate, was concluded to have caused nitrification failure. Leachate zinc concentrations of up to 130 mg/L did not affect treatability providing sufficient phosphorus was present. Addition of chromium (50 mg/L) and nickel (2.0 mg/L), separately, to leachate also resulted in nitrification inhibition. However, phosphorus deficiency was not noted at the point of inhibition for either chromium or nickel. Addition of manganese (50 mg/L) to leachate did not inhibit nitrification in a similar aerobic/anoxic system.  2.1.2  External Carbon Sources for Denitrification  The high ammonia leachates used in the various studies at UBC contain low concentrations of biodegradable organic carbon.  Therefore, external carbon sources are required for denitrification.  Manoharan et al (1989) investigated the use of methanol and glucose as carbon sources when treating leachate containing mean concentrations of ammonia and respectively.  BOD5 of 188 mg N/L and 25 mg O2/L,  Glucose was found to cause unreliable nitrification and denitrification.  Fermentative  conditions in the anoxic reactor were hypothesized to have provided a competitive environment for facultative anaerobes at the expense of denitrifying organisms. Unused glucose exiting the anoxic reactors caused inhibition of nitrification in the aerobic reactors. Methanol addition was found to result in stable and reliable nitrification and denitrification. In addition to process stability, methanol also has the benefits of low cost, availability, lack of nitrogen and phosphorus, favorable solids production, and low volatile organic compound potential (Yoder et al 1995).  Methanol, acetate, glucose, and brewery yeast were used as external carbon sources in a similar study by Carley and Mavinic (1991). Methanol and acetate were found to be the "most effective and trouble free" carbons sources. COD:NOx requirements for complete denitrification were 6.2:1 for methanol and 5.9:1 for acetate.  The brewery yeast also resulted in satisfactory system performance; however, a larger  COD:NOx ratio (8.5:1) was required for complete denitrification.  Similar to the earlier study by  Manoharan et al (1989), glucose was found to result in erratic system performance, due to suspected fermentative conditions in the anoxic reactor.  14  2.1.3  Cold Temperature Performance  Guo (1992) investigated the effects of low temperatures on nitrification and denitrification. Average effluent ammonia concentrations of less than 2 mg N/L were achieved when treating leachate containing about 200 mg N/L of ammonia at a temperature of 4°C and an aerobic SRT of 60 days. A 20 day aerobic SRT resulted in erratic nitrification with an average effluent ammonia concentration of about 9 mg N/L. Reductions in methanol loadings, following decreases in temperature, were necessary to prevent excess methanol from bleeding into the aerobic reactors and further inhibiting nitrification. Once the nitrifying organisms acclimatized to the reduced temperature, methanol loadings could be increased to match the increased denitrification requirements due to increased nitrification activity.  A study by Azevedo (1993) found that systems with 10 and 20 day aerobic SRT's experienced significant nitrification inhibition (i.e. % nitrification = 20%) at 10°C when treating leachate with a "simulated" ammonia concentration of 1500 mg N/L. Denitrification decreased from 99% to 30% in the 10 day SRT system andfrom99% to 82% in the 20 day SRT system. Nitrification was reestablished when aerobic wasting and anoxic methanol addition were ceased.  2.1.4  Hydraulic Retention Time/Sludge Recycle Effects  Elefsiniotis et al (1989) investigated increasing sludge recycle flow rates, hence recycle ratios, as a means of reducing NOx concentrations in effluentsfromMLE systems treating leachate containing about 240 mg N/L of ammonia. Sludge recycle ratios greater than 6:1 (anoxic AHRT < 1.71 hrs, aerobic AHRT < 3.42 hrs) resulted in unstable nitrification/denitrification and increased effluent NOx, and suspended solids concentrations. However, system ammonia removal remained at nearly 100%, regardless of the recycle ratio. Reductions in reactor actual hydraulic retentiontimesat larger recycle ratios was thought to have caused insufficient contact time for complete nitrification artd denitrification. Bacterial assimilation of ammonia and ammonia stripping ensured complete system ammonia removal, even though nitrification became unstable at higher recycle ratios.  15  2.1.5  Increased Leachate Ammonia Levels  Azevedo (1993) artificially increased ammonia concentrations in leachate being treated by 10 and 20 day aerobic SRT systems until the systems failed. Both systems were able to produce effluents with less than 1 mg N/L of ammonia and about 170 mg N/L of NOx from leachate containing 1500 mg N/L of ammonia.  Increases in leachate ammonia concentration from 1500 to 2000 mg N/L resulted in %  nitrification values decreasing from greater than 90% to about 20% in both systems. "Free" ammonia toxicity of ammonia oxidizing organisms (Nitrosomonas), insufficient dissolved oxygen concentrations, and overflow problems were postulated to have caused nitrification failure.  2.2  Hydraulic Studies  Studies investigating the effects of hydraulic retentiontimesand recycle ratios on MLE systems treating nitrogenous wastes are summarized below.  Argaman and Brenner (1986) found that decreasing aerobic AHRT's from 8.9 hrs to 4.6 hrs, by increasing sludge recycle flows, resulted in a decrease in aerobic ammonia removal from 95% to 40%, when treating domestic sewage that was spiked with ammonium chloride to provide an ammonia concentration of about 250 mg N/L.  A further reduction in aerobic AHRT to 3.2 hrs yielded an aerobic ammonia removal  efficiency of only 17%. Aerobic VSS levels were similar in all runs. Nitrification was found to follow zero-order kinetics, providing aerobic ammonia concentrations were greater than 2.0 mg N/L. Increased sludge recycle ratios, up to 14:1, did not result in reduced effluent NOx concentrations because of carbon shortages in the wastewater. In addition, actual effluent NOx concentrations were found to increase at higher recycle ratios due to poor denitrification kinetics associated with low carbon concentrations in the anoxic reactors. Mathematical modelling of predenitrification systems by Brenner and Argaman (1990) yielded similar findings.  Szpykowicz et al (1991a,b) treated tannery wastewater containing about 200 mg N/L of ammonia and 1000 mg O2/L BOD5 using an MLE system having clarifier sludge (1:1) and aerobic mixed liquor recycles. Average effluent ammonia concentrations of less than 4 mg N/L were achieved with aerobic 16  AHRT's as low as 2.9 hrs. Increases in aerobic mixed liquor recycle from 10:1 to 14:1 did not result in reduced effluent NOx levels due to carbon shortages. Anoxic dissolved oxygen concentrations were less than 0.1 mg/L, but the entrainment of oxygen into the anoxic mixed liquor, from the aerobic recycle, was estimated to have caused the elimination of 6% of the incoming COD by using oxygen as the electron acceptor rather than NOx.  Large COD:NOx ratios (i.e. up to 12.5) were required for complete  denitrification, thus suggesting the presence of significant quantities of oxygen entering the anoxic reactor.  Argaman (1982) also found very large anoxic BOD removals when using an aerobic mixed liquor recycle ratio of 30:1. The amount of BOD and NOx removed across the anoxic reactor can be used to calculate a BOD:NOx ratio of 29.2:1. Aerobic oxidation of organic carbon, within the anoxic reactor, was suggested as a reason for the large amount of anoxic BOD removal, even though dissolved oxygen concentrations were less than 0.5 mg/L.  A predenitrification modelling study conducted by Jain et al (1992) found that anoxic denitrification performance was negatively affected by the introduction of oxygen contained within the aerobic mixed liquor recycle. Higher recycle rates and/or lower anoxic AHRT's compounded the negative effects of oxygen on denitrification.  Robinson (1992) used an MLE system to treat leachate containing 1100 mg N/L of ammonia. A recycle ratio of 10:1 resulted in effluent NOx concentrations between 75 and 100 mg N/L, with ammonia levels less than 0.1 mg N/L.  AHRT's of the anoxic and aerobic reactors were about 17 hrs and 55 hrs,  respectively.  The effect of decreasing reactor HRT's, in an MLE system, on nitrification/denitrification of domestic sewage was investigated by Wanner et al (1990). Decreases in aerobic HRT from 5.8 to 3.8 hrs did not affect nitrification. Similarly, denitrification remained unaffected when anoxic HRT's were reduced from 3.3 to 2.2 hrs. Recycle ratios were maintained at about 1.5:1 for all trials; therefore, decreases in HRT were caused by increasing influentflowrates. 17  Gee et al (1990) treated a simulated waste containing 1000 mg N/L of ammonia in a completely mixed aerobic reactor without solids recycle. Complete nitrification was still attained at an aerobic HRT of 2.7 days; however, nitrification failed when the HRT was further reduced to 2.0 days. VSS levels increased as the HRT was decreased from 10 days (200 mg/L) to 2.7 days (300 mg/L). The reduction in VSS at higher HRT's was assumed to be the result of cell decay.  2.3  Reactor Configuration  The importance of anoxic organic carbon levels on denitrification performance was investigated by Panzer et al (1981), by using a four stage anoxic reactor to simulate plug flow conditions in an MLE system treating tannery waste. Specific denitrification rates in the first stage were up to four times greater than those of the third and fourth stages. Decreasing COD concentrations in the latter stages resulted in substrate limited denitrification. Hence "staged" or plug flow anoxic reactors were concluded to more efficiently utilize available carbon for denitrification.  Chudoba et al (1985) compared plug flow and complete mix aeration tank configurations with respect to nitrification kinetics. The plug flow system had specific ammonia oxidation rates that were almost twice those of the complete mix system. The half velocity constant for the plug flow system was about 40% smaller than the complete mix system. Larger bulk ammonia concentrations in the plug flow system were thought to have allowed for the diffusion of ammonia into the centre of the floes, thus allowing active nitrifiers to be present throughout the entire floe and resulting in lower half velocity constants and higher specific ammonia oxidation rates.  2.4  Nitrification Inhibition  The effects of carbon loading and heterotrophic activity on nitrification was studied by Hanaki et al (1990a). Ammonia oxidation within the complete mix aerobic reactor, without solids recycle, decreased as influent COD (glucose) levels were increased.  In addition, ammonia oxidation was inhibited to a  greater extent at lower HRT's for a given COD loading. It was hypothesized that "crowding" of ammonia oxidizing organisms by heterotrophic bacteria, at higher COD loadings, hindered the transport of ammonia 18  and oxygen from bulk solution to ammonia oxidizers within the floes. Further study (Hanaki et al 1990b) confirmed that the inhibitory effect of organic loading on ammonia oxidation was enhanced by low dissolved oxygen concentrations.  Azevedo (1993) also found inhibition of nitrification when excess methanol from anoxic reactors was bleeding into aerobic reactors of MLE systems treating leachate. High aerobic BOD5 values correlated "reasonably well" with lower % nitrification values. Bulk solution dissolved oxygen levels were always sufficient for nitrification. However, actual oxygen concentrations within the floes may not have been sufficient for Nitrosomonas organisms.  Anthonisen et al (1976) investigated the effects of ammonia and nitrous acid on inhibition of nitrification. "Free" ammonia concentrations of 10 to 150 mg N/L were found to initiate inhibition of  Nitrosomonas  organisms;  Nitrous acid  inhibition began at concentrations of 0.1 to 1.0 mg N/L.  Nitrobacter  concentrations between 0.22 and 2.8 mg/L were found to initiate inhibition of both organisms. The degree of inhibition due to "free" ammonia and nitrous acid was theorized to be a function of temperature, acclimation, and numbers of nitrifying organisms.  Turk (1986) attempted to induce and sustain nitrite accumulation, by inhibiting Nitrobacter, in order to reduce organic carbon requirements for denitrification when treating nitrogenous wastes. "Free" ammonia concentrations of 5 to 10 mg N/L inhibited unacclimatized nitrite oxidizing organisms. However, "free" ammonia concentrations of up to 40 mg N/L did not inhibit either ammonia or nitrite oxidation of acclimated systems. Internal recycle, such as that used in a predenitrification process, continually recycles nitrifiers through high anoxic "free" ammonia concentrations and was found to be the most effective way of delaying acclimation.  The effects of extreme substrate, product and salt concentrations on the ammonia oxidizing bacteria Nitrosomonas  eurpaea  were investigated by Hunik et al (1992). Results of pure culture chemostat studies  revealed that, although severe inhibition occurred for all substances tested, no significant differences 19  between ammonia, nitrite and various salts were observed. concentrations were concluded to have caused the inhibitions. pH's, due to the formation of nitrous acid.  20  Osmotic pressure due to high salt Nitrite was found to be inhibitory at low  Chapter 3 EXPERIMENTAL SETUP AND OPERATION  Two different process configurations were used during the course of this study.  The first was a  predenitrification system known as the Modified Ludzack-Ettinger (MLE) process. Two identical MLE systems were used during the MLE Startup Phase and MLE Recycle Phase.  The second process  configuration was a pre and postdenitrification system known as the Bardenpho process.  A single  Bardenpho system was used during the Bardenpho Phase of the study.  3.1  M L E System Design  The MLE systems, shown in Figure 1.1, consisted of an anoxic reactor, aerobic reactor, and a clarifier. The anoxic reactor was used for denitrification of nitrified sludge returned from the clarifier. It was constructedfroma plastic container and had a volume of 5 litres. An electric motor and stirring rod was used to keep the anoxic mixed liquor completely mixed and in suspension. A mixing speed of about 50 rpm provided adequate mixing while minimizing the entrainment of oxygen into the reactor. An ORP probe continuously monitored the oxidation-reduction potential within the anoxic reactor. Mixed liquor from the anoxic reactor flowed into the aerobic reactor by gravity.  The aerobic reactor was used for nitrification of mixed liquor from the anoxic reactor.  It was also  constructed from a plastic container, and had a volume of 10 litres. Two small porous stones, located at the bottom of the reactor, were used to supply air required for nitrification. Dissolved oxygen levels were maintained above 2.0 mg/L. Air flow was manually controlled using flow meters connected to the laboratory compressed air supply line. The mixed liquor was kept in suspension by an electric motor and stirring rod. Mixed liquorfromthe aerobic reactor flowed into the clarifier by gravity.  A clarifier constructed of Plexiglas, with a volume of 4 litres, was used to settle solids from the final effluent and to produce a thickened sludge that was returned to the anoxic reactor for denitrification. Mixed liquor entered the clarifier through an inner, cylindrical baffle intended to prevent short circuiting. 21  Sludge was withdrawn from the conical bottom of the clarifier. The sludge was pumped back to the anoxic reactor using a peristaltic pump operating intermittently at 1 minute on and 3 minutes off. Intermittent pumping was used to prevent recycle line blockages (Azevedo 1993). A stainless steel rod, attached to a 1 rpm electric motor, was used to scrape solids from the sides and bottom of the clarifier.  3.2  Bardenpho System Design  The Bardenpho System (Figure 1.2) was created using reactors from both MLE systems.  The  "predenitrification" section consisted of the anoxic and aerobic reactors from MLE System 1. The clarifier from System 1 was not used.  The "postdenitrification" section consisted of the anoxic and  aerobic reactors and clarifier from MLE System 2. Mixed liquor from Aerobic #1 was pumped to Anoxic #2 by a peristaltic pump operating at 1 minute on and 9 minutes off.  Sludge from the clarifier was  pumped to Anoxic #1 by a peristaltic pump operating at 1 minute on and 9 minutes off. Mixed liquor from Aerobic #1 was recycled to Anoxic #1 by a peristaltic pump operating at 1 minute on and 3 minutes off.  3.3  Leachate Feed  The leachate used in this study was from the Bums Bog Landfill located in Delta, British Columbia. Leachate was collected once a week and stored at 4°C to prevent any changes in quality. Actual leachate collection was from a sampling line connected to the pressurized pipeline exiting a wet well. The wet well was located at the southwest comer of the landfill.  The landfill began operations in 1966 (Azevedo 1993) and continues to be used today. Table 3.1 contains a summary of leachate composition for the study period. High ammonia and low carbon concentrations typical of an "older" landfill are illustrated in the data.  22  Table 3.1 Burns Bog Leachate Composition  Parameter N.H4-N NOx-N NO9-N O-PO4  Mean Concentration (mg/L) 198 0.4 0.2 0.4  pH (pH units) Alkalinity (as CaCO^) TSS VSS BOD^ COD Cr* Ni* Zn*  ~  1600 45 23 31 374 < 0.03 <0.03 0.05  Range (mg/L) 80 - 392 0.2-1.6 0.0-0.5 0.0-1.0 6.8-7.8 750 - 2300 16-89 8-48 11 -50 188-596 N.D. - 0.03 N.D. - 0.04 0.04 - 0.06  * City of Vancouver, Monthly Composite Data, July - November, 1995  Leachate was fed to the anoxic reactors of the MLE systems by peristaltic pumps that continuously pumped leachatefroma covered, plastic pail that was slowly stirred using an electrical motor and stirring rod. Leachate was only fed to Anoxic #1 of the Bardenpho system. Stored leachate (4°C) was allowed to come to "room" temperature (20°C) before it was added to the feed pail. A siphon was used to transfer leachatefromthe storage containers to the feed pail, in order to prevent excess aeration of the leachate.  The leachate flow rate was set to approximately 9 L/d so as to be similar to previous UBC studies (Elefsiniotis et al 1989, Guo 1992, Azevedo 1993). The total flow into the systems was about 10 L/d, because of the various chemical additions.  3.4  Chemical Addition  The peristaltic pumps used to add various chemical solutions to the systems were set to pump at the lowest flow rates that could "reliably" be maintained (i.e. 5 to 10 mL/hr). This was done to minimize dilution and HRT effects from addition of chemical solutions. changing the concentration of the feed solutions.  23  Chemical loadings, therefore, were adjusted by  Phosphorus solutions were added to the anoxic reactors of the systems to ensure biologically available phosphorus levels were sufficient for nitrification and denitrification.  Both anoxic reactors of the  Bardenpho system were fed phosphorus solutions. In keeping with earlier results by Manoharan et al (1992), reactor ortho-phosphate concentrations were generally maintained above 2.0 mg P/L . Dibasic sodium phosphate (Na2HP04-7H20) was used to make up the solutions. Mass loadings were calculated based on daily volumetric changes within the 1000 ml graduated cylinders, used for solution storage, and solution concentrations.  Methanol (CH3OH), added to the anoxic reactors, was used as the organic carbon source required for denitrification. Solution concentrations were adjusted based on requirements for complete denitrification. Mass loadings were calculated based on daily volumetric changes within the 1000 ml graduated cylinders, used for solution storage, and solution concentrations.  Elevated leachate ammonia concentrations were "simulated" by adding ammonium chloride (NH4CI) solutions to the anoxic reactors of the MLE systems. Ammonium chloride was only fed to Anoxic #1 of the Bardenpho system. Ammonia concentrations of the "simulated" leachate were calculated based on daily volumetric changes within the 1000 ml graduated cylinders (used for solution storage), ammonium chloride solution concentrations, and "base" leachate feed rates and ammonia concentrations.  Sodium bicarbonate (NaHC03) solutions were added to the aerobic reactors as required to maintain aerobic pH levels at 7.5. This was done using Cole Parmer 7142 pH/pump controllers that continuously monitored aerobic pH levels and pumped sodium bicarbonate solutions from 1000 ml graduated cylinders into the aerobic reactors when the pH dropped below 7.5.  The solutions were maintained at 80 g  CaC03/L (i.e. near saturation) in order to minimize the volume of solution pumped into the reactors.  3.5  MLE System Startup and Operation  On July 7, 1994 the aerobic reactors and clarifiers of both MLE systems were filled with anoxic mixed liquor from the Biological Phosphorus Removal (Bio-P) Pilot Plant located at the University of British 24  Columbia.. Leachate and phosphorus solutions were directly fed into the aerobic reactors. Sludge from the clarifiers was recycled back to the aerobic reactors at a ratio of 6:1. Stable and complete nitrification of the "base" leachate was attained in both systems by day 35; therefore, the anoxic reactors were filled with Bio-P anoxic mixed liquor on August 11, 1994. Leachate, and methanol and phosphorus solutions were then fed to the anoxic reactors. Clarifier sludge was recycled to the anoxic reactors at a starting ratio of 6:1. Aerobic wasting began on August 19, 1994 at the rate of 0.5 L/d, and eventually increased to 0.67 L/d (September 14, 1994) and 1.0 L/d (November 29, 1994). Complete nitrification and denitrification of the "base" leachate was reached in both systems by day 70 (September 16, 1994).  Leachate ammonia concentrations were incrementally increased from levels contained within the "base" leachate to the "target" concentration of 1200 mg N/L. Anoxic methanol loadings were kept constant at levels required to denitrify the "base" leachate. The first attempt at reaching the "target" concentration occurred between September 17, 1994 and October 23, 1994. Nitrification failure in both systems, caused by "free" ammonia toxicity (discussed in Section 5.1), resulted in a second attempt to reach the "target" concentration. Starting again with the "base" leachate, ammonia levels were incrementally increased, at a rate similar to the first attempt, beginning on October 30, 1994. The same sludge was used; therefore, the reactors were not re-seeded. However, anoxic methanol loadings were also increased at the same time leachate ammonia concentrations were increased. By November 20, 1994 both systems were successfully treating leachate containing 1200 mg N/L of ammonia. Specific details regarding leachate ammonia increments and anoxic methanol loadings are presented in Sections 5.1 and 5.1.3.  The MLE Recycle Phase was conducted between December 14, 1994 and March 7, 1995. Clarifier sludge recycle flows were increased on December 14, 1994 to yield recycle ratios of 7:1 in System 1 and 8:1 in System 2. Aerobic SRT's of 10 days were initially used in both systems; however, these were eventually increased to 20 days, in order to improve nitrification performance. Reductions in leachate ammonia concentrations, begun on February 14, 1995, were initiated in an attempt to remove residual ammonia remaining in the effluents.  25  The MLE systems were setup in a temperature controlled room maintained at about 20°C.  3.6  Bardenpho System Startup and Operation  The two MLE systems were converted to the Bardenpho System on March 8, 1995.  The conversion  simply consisted of plugging the overflow from Aerobic #1 to Clarifier #1, positioning a peristaltic pump to transfer mixed liquor from Aerobic #1 to Anoxic #2, and relocating the sludge recycle line from Clarifier #2 to discharge into Anoxic #1. The mixed liquor recycle from Aerobic #1 to Anoxic #1 was set at a ratio of 4:1. The clarifier sludge recycle flow was set to give a recycle ratio of 3:1.  Sludge wasting was conducted at a rate of 0.5 L/d from Aerobic #1, thus resulting in an Aerobic #1 SRT of 20 days. A "simulated" leachate ammonia concentration of 1100 mg N/L was maintained throughout the Bardenpho Phase. The room temperature was kept at about 20°C. The Bardenpho Phase, upon the system reaching "steady state", was terminated on April 7, 1995.  26  Chapter 4 A N A L Y T I C A L METHODS  This chapter outlines the analytical methods used in the determination of various chemical constituents within the leachate, reactor mixed liquors, and effluents.  Samples were collected two or threes times a  week for analysis, except where otherwise indicated.  4.1  Ammonia ( N H + N H ) +  3  4  Leachate, mixed liquor and effluent samples were analyzed for ammonia using a Lachat Quikchem Automated Ion Analyzer. Samples were filtered through Whatman #4 filters, diluted as necessary, pH adjusted using sulphuric acid to a pH of 3.0, and stored at 4°C until analysis. Samples were pH adjusted to 3.0 because the ammonia standards were prepared with the same pH. Ammonia concentrations were determined using methods outlined in the Methods Manual for the Quikchem Automated Ion Analyzer (1987).  Aerobic mixed liquor ammonia concentrations were also estimated using an Orion Model 95-10 ammonia probe and a Cole Parmer Chemicadet Series 5984 pH/mV meter.  This method allowed for daily  "screening" of aerobic ammonia levels and gave an indication of system nitrification performance. Unfiltered 50 ml samples were pH adjusted to approximately pH 11 using 0.5 ml of 10 M NaOH as outlined in the Orion Ammonia Electrode Instruction Manual. An initial mV reading was taken, then 5 ml of an ammonium chloride standard solution was added to the sample and the final mV reading recorded. Standard solutions (1.4, 14, 140, 1400 mg N/L) containing approximately ten times the "suspected" sample ammonia concentration were added to the samples. The ammonia concentration of the sample was then calculated using the difference in the mV readings, the ammonia concentration of the standard solution, and a table contained in the Orion instruction manual.  27  4.2  Nitrate plus Nitrite (NOx)  Leachate, mixed liquor and effluent samples were analyzed for NOx using a Lachat Quikchem Automated Ion Analyzer. Samples were filtered through Whatman #4 filters, preserved with several drops of phenyl mercuric acetate, diluted as necessary, and stored at 4°C until analysis.  NOx concentrations were  determined using methods outlined in the Methods Manual for the Quikchem Automated Ion Analyzer (1987).  4.3  Nitrite ( N 0 ) 2  Leachate, mixed liquor and effluent samples were analyzed for N 0 using a Lachat Quikchem Automated 2  Ion Analyzer. Samples werefilteredthrough Whatman #4 filters, preserved with several drops of phenyl mercuric acetate, diluted as necessary, and stored at 4°C until analysis.  N0  2  concentrations were  determined using methods outlined in the Methods Manual for the Quikchem Automated Ion Analyzer (1987).  4.4  Orthophosphate (Ortho-P)  Leachate, mixed liquor and effluent samples were analyzed for orthophosphate using a Lachat Quikchem Automated Ion Analyzer. Samples werefilteredthrough Whatman #4 filters, preserved with several drops of phenyl mercuric acetate, and stored at 4°C until analysis.  Orthophosphate concentrations were  determined using methods outlined in the Methods Manual for the Quikchem Automated Ion Analyzer (1987).  A comparison of ortho-p concentrations when samples werefilteredthrough Whatman #4 filters and 0.45 um membranefilterswas initially conducted in response tofindingsby Manoharan et al (1992). Ortho-P concentrations were virtually identical (i.e. within method reproducability tolerances) in both sets of samples; therefore, Whatman #4 filtered samples were concluded to reliably estimate biologically available phosphoms levels and were used for the remainder of the study.  28  4.5  Solids (TSS and VSS)  Leachate, mixed liquor and effluent samples were analyzed for total suspended solids (TSS) and volatile suspended solids (VSS) using a modification (Azevedo 1993) of the Standard Methods (A.P.H.A. 1985) procedure. A stainless steel filtration apparatus and aluminum filter holders replaced the ceramic Gooch filtration units specified in Standard Methods.  This modification reduced the possibility of errors  associated with absorption of moisture onto the filter paper holders.  4.6  Biochemical Oxygen Demand ( B O D 5 )  Biochemical Oxygen Demand levels in the leachate, mixed liquors and effluents were determined using the methods outlined in Standard Methods (A.P.H.A. 1985). Samples werefilteredthrough Whatman #4 filters prior to the addition of dilution water. The dilution water was seeded with 1 ml of aerobic mixed liquor per 10 1 of dilution water. In addition, nitrification inhibitor (Hach Formula 2533) was added to the dilution water at a concentration of 10 mg/L, to eliminate the oxygen consumption effects of nitrifiers contained within the mixed liquor seed. A Yellow Springs Instrument Company Model 54 Dissolved Oxygen Meter and self mixing probe was used to determine initial and final dissolved oxygen concentrations of the samples.  Leachate, reactor and effluent samples were collected once a week for BOD5 determination.  4.7  Chemical Oxygen Demand (COD)  Chemical Oxygen Demand levels in the leachate, mixed liquors and effluents were determined using the closed reflux, colorimetric method outlined in Standard Methods (A.P.H.A. 1985). Samples were filtered through Whatman #4 filters, acidified to pH < 2 with sulphuric acid, and stored at 4°C until analysis. Mercuric sulphate was included in the digestion solution to eliminate effects of chloride contained within the samples.  Samples were occasionally centrifuged after digestion to settle particulate matter (i.e.  precipitates) suspended in the samples. COD values for samples containing nitrite were corrected by subtracting 1.1 mg O2/L per mg NO2-N/L to account for the oxygen demand of nitrite (A.P.H.A. 1985).  29  4.8  Alkalinity (as CaC0 /L) 3  Leachate alkalinity analyses were conducted once a week on each batch of leachate collected from the landfill.  Samples were filtered through Whatman #4 filters and analyzed using methods outlined in  Standard Methods (A.P.H.A. 1985). Samples were titrated to a pH endpoint of 4.3 as determined using a pH meter and probe.  Reactor mixed liquor and effluent samples were occasionally analyzed for alkalinity during periods of nitrification inhibition. The analyses were conducted in the same manner as that for the leachate samples.  4.9  pH  Unfiltered leachate and mixed liquor pH levels were measured using a Cole Parmer Chemcadet Series 5986 pH meter with a Ag-AgCl combination pH electrode. Meter calibration was checked before each use with a pH = 7.01 buffer solution. Recalibration, if necessary, was performed using pH = 7.01 and pH = 10.01 buffer solutions.  Cole Parmer Model 7142 pH/pump controllers with Ag-AgCl combination pH electrodes monitored aerobic pH levels. The controllers were calibrated using pH = 7.01 and pH = 10.01 buffer solutions. However, electrical "noise" from the various motors resulted in pH levels displayed by the controllers to be slightly differentfromthose obtained using the above "bench top" meter. Therefore, readings obtained using the "bench top" meter were used for data collection. In addition, the setpoints on the pH controllers were adjusted such that aerobic pH levels were 7.5 as indicated by the "bench top" meter. Aerobic pH probes were cleaned weekly with distilled water and, on occasion, using a mild soap solution.  4.10  Oxidation-Reduction Potential (ORP)  ORP values in the anoxic reactors were continuously monitored by submerged Broadly James Corporation ORP electrodes (one per reactor) connected to Cole Parmer Chemcadet Series 5984 pH/mV meters. Probe response was initially checked with pH-buffered quinhydrone solutions (Broadly James  30  Corporation Electrode Instructions ORP (REDOX) Combination Electrode).  Both probes were  "standardized" to read 000 mV in tap water. The ORP probes were cleaned weekly with distilled water.  4.11  Dissolved Oxygen (DO)  A Yellow Springs Instrument Company Model 54 Dissolved Oxygen Meter with a Yellow Springs Instrument Company Model 5739 submersible probe was used to determine in-situ aerobic mixed liquor DO concentrations about every second day. The meter was calibrated using the air calibration method as outlined in the Instruction Manual for YSI Models 54 ARC and 54 ABP Dissolved Oxygen Meters. The probe membrane was changed when the meter failed air calibration. The probe was cleaned with distilled water after each use.  4.12  Temperature  The experimental apparatus was set up in a temperature controlled room.  Two identical, alcohol  thermometers, in addition to the thermometer built into the temperature controller, were used monitor room temperature.  31  Chapter 5 RESULTS AND DISCUSSION  The results obtained from this study are presented and discussed in this chapter. The study was divided into three phases: (1) MLE Startup Phase; (2) MLE Recycle Phase; and (3) Bardenpho Phase.  Two  identical, predenitrification, single sludge, activated sludge systems, known as the Modified LudzackEttinger (MLE) process, were used in the first two phases of the study. The third phase combined components of the two MLE systems into one four-stage, pre and postdenitrification system known as the Bardenpho process.  The MLE Startup Phase involved the initial startup of the two MLE systems using the "base" leachate followed by artificially increasing the leachate ammonia concentration to a "target" level of approximately 1200 mg N/L, to simulate a higher strength leachate. An initial clarifier recycle rate of 6:1 (sludge recycle flow: leachate flow) and aerobic solids retention time (SRT) of 13 days were used for both systems. Aerobic SRT's were reduced to 10 days once the "target" leachate ammonia concentration was reached.  The MLE Recycle Phase was begun once both systems were treating 1200 mg N/L ammonia leachate in a stable manner. According to MLE  process theory, increases in sludge recycle rate should result in  reduced effluent oxidized nitrogen (NOx) concentrations. Therefore, the purpose of this phase was to investigate the effects of increased sludge recycle rates on nitrification, denitrification and effluent NOx concentrations. Sludge recycle rates were increased to 7:1 in one system and 8:1 in the other system. The effects of increased SRT and reduced ammonia mass loadings on process performance were also investigated.  The final phase of the study, the Bardenpho Phase, was conducted to verify that a combined pre and postdenitrification system could successfully remove virtually all nitrogen from leachate containing 1200 mg N/L of ammonia.  32  Calculation definitions are shown in Appendix A with raw and calculated data contained in Appendix B.  5.1  MLE Startup Phase  This section presents and discusses data collected from the time the MLE systems were initially started (Day 1 - July 7, 1994) until the beginning of the MLE Recycle Phase (Day 157 - December 12, 1995). Three distinct periods existed during this startup phase: establishment of nitrification and denitrification using the "base" leachate, incrementally increasing leachate ammonia concentrations followed by nitrification failure in both systems, and systems recovery and second attempt at increasing leachate ammonia concentration. The failure of both systems, while attempting to reach the "target" leachate ammonia concentration of 1200 mg N/L, was unexpected, given the results obtained in a previous study by Azevedo (1993) where a simulated leachate with an ammonia concentration of 1500 mg N/L was successfully treated using identical systems. Hence this section will focus on documenting the systems nitrification failure, subsequent recovery and eventual success in reaching the "target" 1200 mg N/L ammonia concentration. In maintaining consistency with the earlier study conducted by Azevedo (1993), "ammonia" and "NH4" refers to "total" ammonia. "Total" ammonia is the sum of "free" ammonia (NH3) and the ammonium ion (NH4 ). +  The objective of the MLE Startup Phase was to achieve stable nitrification and denitrification, in both systems, of leachate containing 1200 mg N/L of ammonia. Once the systems were successfully treating the "base" leachate (i.e. 230 mg NH4-N/L), the ammonia concentration of the leachate was incrementally increased by the addition of ammonium chloride solutions to the systems.  "Simulated" leachate  containing ammonia concentrations of approximately 400, 600, 800 and 1000 mg N/L were incrementally fed to both systems. The procedure for increasing the leachate ammonia concentration consisted of feeding the appropriate amount of ammonium chloride to the anoxic reactors, to yield the desired simulated leachate ammonia concentration, while monitoring, daily, the aerobic reactor ammonia concentrations using the ammonia probe. The absence of ammonia accumulation in the aerobic reactors was interpreted as the systems responding favorably to the increased ammonia loading. The total volume of the anoxic and aerobic reactors and the clarifier was 19 litres; therefore, at a leachate feed rate of about 33  10 L/d, the system hydraulic retention time (SHRT) was approximately 2 days. At least 3 days were allowed between ammonia loading increments to ensure the systems were removing all of the ammonia.  Methanol loadings to the anoxic reactors remained constant during this period and were maintained at the actual amount required for complete denitrification of the "base" leachate. The rationale for this method was based on results from the previous study by Azevedo (1993). He found that large increases in methanol loading may result in excess bleeding of unused methanol from the anoxic reactors into the aerobic reactors, causing inhibition of mtrification, (presumably by heterotrophic competition for oxygen in the aerobic reactors and/or methanol toxicity to Nitrosomonas).  Reaching the "target" leachate  ammonia concentration of about 1200 mg N/L as quickly as possible was desired; therefore, in order to avoid the possible inhibitory effects of simultaneously increasing the methanol loadings, it was decided to first incrementally increase the ammonia loadings to the systems until the "target" leachate ammonia concentration was reached. Methanol loadings were then to be incrementally increased until complete anoxic denitrification of the "target" leachate was attained.  The following sections discuss the first attempt at reaching the "target" leachate ammonia concentration of 1200 mg N/L and the resulting nitrification failure in both systems, nitrification recovery, second attempt at reaching the "target" leachate ammonia concentration, and possible explanations for the initial nitrification failure.  5.1.1  Incremental Ammonia Loading and Nitrification Failure  By day 70, both systems were treating the "base" leachate with essentially 100 % removal of ammonia in the aerobic reactors and NOx in the anoxic reactors. As shown in Figures 5.1 and 5.2, the "base" leachate being fed to both systems consistently contained about 230 mg N/L of ammonia during this period. The addition of ammonium chloride solutions to the anoxic reactors of both systems began on day 71, with a simulated leachate ammonia concentration of about 400 mg N/L. Further increments to 600 and 800 mg N/L ammonia were made on days 74 and 78, respectively.  34  35  o o  o o  CM  (l/N Bui)  o o o  o o  o o oo  CO  o o  o o  CM  uouBJjuaouoo e m o u i u i v aieuoeen p a a j  36  Figures 5.3 and 5.4 show the ammonia concentrations in the anoxic and aerobic reactors of Systems 1 and 2. Aerobic ammonia concentrations were still essentially zero at day 81; therefore, the simulated leachate ammonia concentration was increased to about 1000 mg N/L. Elevated aerobic ammonia concentrations appeared in both systems by day 84; hence no further increases in ammonia loading were made. By day 95, the aerobic ammonia concentration in System 1 was about 100 mg N/L and 270 mg N/L in System 2. Between days 91 and 95, the aerobic ammonia concentrations in System 2 were at least twice as high as the values for System 1, based on data obtained using the ammonia probe.  Azevedo (1993) found that after making similar increments in ammonia loading, an ammonia "spike" would appear in the anoxic and aerobic reactors immediately following the increment. However, aerobic ammonia levels would return to basically zero within several days, thus indicating complete ammonia oxidation. It should be noted that "nitrification" refers to the two step conversion of ammonia to nitrite and then to nitrate. "Ammonia oxidation" is the conversion of ammonia to nitrite. These terms are used interchangeably, in this discussion, to describe the conversion of ammonia to NOx .  Since reactor  ammonia concentrations had been continually rising for almost two weeks (days 82 - 95) in both systems, it was suspected that nitrification was actually failing and not just undergoing a transient response to the increment of feeding 1000 mg N/L ammonia leachate. Two remedial measures were attempted to remove excess ammonia and restore complete nitrification in the systems: (1) increased methanol loadings to both systems; and (2) a decrease in ammonia loading to System 2, in response to the much larger reactor ammonia concentrations compared to System 1. Methanol loadings, shown in Figures 5.5 and 5.6, to both systems were increased slightly on day 95, with the intent of stimulating more heterotrophic bacterial growth in the anoxic reactors and, therefore, assimilating some of the excess ammonia.  Since the  methanol loadings were based on denitrifying the NOx produced when treating the "base" leachate (i.e. 230 mg NH4-N/L), there was little danger of excess methanol bleeding into the aerobic reactors from the anoxic reactors. On day 95, the ammonia concentration of the simulated leachate being fed to System 2 was reduced to about 900 mg N/L. System 1 continued to be fed 1000 mg N/L ammonia leachate.  37  38  39  40  41  The result of these measures was an immediate drop in reactor ammonia concentrations and, by day 98, both systems had almost identical ammonia concentrations in their respective reactors (anoxic =170 mg N/L; aerobic = 60 mg N/L). However, by day 103, reactor ammonia levels were quickly rising again in both systems. Methanol loadings were again increased to both systems on day 103 but without any apparent effect. By day 107, anoxic ammonia concentrations in both systems exceeded 500 mg N/L, with aerobic concentrations of about 450 mg N/L.  Further evidence supporting nitrification failure in both systems can be found in pH and alkalinity data. Figures 5.7 and 5.8 show the anoxic and aerobic pH of systems 1 and 2 during the MLE startup phase. Sufficient alkalinity was present in the leachate to maintain aerobic pH values greater than 7.5 until the simulated leachate ammonia concentration reached approximately 600 mg N/L.  pH/pump controllers  were then used to maintain aerobic pH levels at a setpoint of 7.5, within approximately plus or minus 0.1 units, by the addition of sodium bicarbonate solution. Sodium bicarbonate addition stopped on day 104 for System 1 and on day 102 for System 2, because the aerobic pH levels had increased above the 7.5 setpoint. By day 105, anoxic and aerobic pH levels were almost equal and basically the same in each of the systems. Earlier, anoxic pH levels were always higher than aerobic values, indicating the consumption of alkalinity during aerobic nitrification with the subsequent return of alkalinity during anoxic denitrification. pH levels kept rising until the ammonium chloride feed was turned off; this increase was attributed to continued denitrification of the remaining NOx (formed previously) in the reactors that returned even more alkalinity to the mixed liquor.  Based on these data, it appeared that nitrification in both systems was severely failing and it was feared that the systems would not recover while being fed such high ammonia leachate. Thus, it was decided to stop the addition of ammonium chloride solutions to the systems on day 107 and, therefore, continue to feed only the "base" leachate. Methanol loadings were also reduced in a corresponding manner to prevent excess methanol from bleeding into the aerobic reactors.  42  43  44  5.1.2  Nitrification Recovery  It took approximately 5 days (day 112) for the aerobic ammonia concentrations, in both systems, to decrease to values of less than 10 mg N/L, once the ammonium chloride feed was turned off (day 107). Removal of excess ammonia from the systems took longer than expected, given that the volume contained wthin the systems would have been exchanged within 2 days (i.e. nominal HRT = approximately 2 days). The additional 3 day lag period before essentially complete nitrification was restored provides additional evidence that nitrification was severely inhibited, and is further supported by an examination of nitrification alkalinity consumption data.  The amount of alkalinity consumed across the aerobic reactors (anoxic alkalinity minus effluent alkalinity) gives an indication of nitrification performance and, more specifically, the condition of the Nitrosomonas organisms responsible for the oxidation of ammonia. Alkalinity is consumed during nitrification at a theoretical ratio of 7.1 mg CaCC^/L per mg NH4-N/L nitrified (EPA 1993). Table 5.1 contains alkalinity data for both systems and shows the amount of alkalinity consumed across the aerobic reactors. Table 5.1 Reactor Alkalinity Data  System 1: Day 107 109 111 System 2: Day 107 109 111  Anoxic Alkalinity (mg CaC03/L) 986 1189 814  Effluent Alkalinity (mgCaC03/L) 757 1015 493  Aerobic Consumption (mg CaC03/L) 229 171 321  1186 1357 1043  1000 1229 729  186 128 314  Anoxic ammonia concentrations, because of dilution of leachate by the clarifier recycle flow, would "normally" be about 140 mg N/L when receiving leachate containing 1000 mg N/L of ammonia. Therefore, aerobic alkalinity consumption, based on the theoretical 7.1:1 ratio, would be expected to be around 1000 mg CaCC^/L, for these systems, when completely nitrifying leachate containing 1000 mg N/L of ammonia. The data in Table 5.1 indicate that nitrification activity continued to decrease even after  45  the additional ammonia loadings to the systems were ceased on day 107. As indicated earlier, the liquid in the systems would have been exchanged by day 109 (SHRT = 2 days), yet the amount of alkalinity consumed by nitrification decreased by about 25% and 31% for systems 1 and 2, respectively, between days 107 and 109. By day 111, nitrification had been significantly restored in both systems as illustrated by the large increases in aerobic alkalinity consumption. The systems continued to be fed only "base" leachate until day 114.  5.1.3  Second Attempt At Incremental Ammonia Loading  The second attempt at reaching the "target" simulated leachate ammonia concentration of 1200 mg N/L was conducted in a similar manner as thefirstattempt described in Section 5.1.1, with the exception of the methanol loadings. Ammonia loading increments, shown in Figures 5.1 and 5.2, were similar to those of thefirstprocedure. As in the first attempt, a period of 10 days (day 114 to day 124) was used to increase the leachate ammonia concentration from that of the "base" leachate to a simulated 1000 mg N/L concentration.  Further ammonia increments were then made so that, by day 135, both systems were  receiving leachate containing between 1150 and 1200 mg N/L of ammonia. Increases in methanol loading were made to both systems within a day or so following the ammonia increments. Methanol loadings, shown in Figures 5.5 and 5.6, were initially calculated based on a assumed denitrification methanol COD: NOx requirement of about 4:1 (Azevedo 1993). Further adjustment of methanol loadings were made once the "target" leachate ammonia concentration was reached, to ensure complete anoxic denitrification of this leachate.  Both systems responded to increases in ammonia and methanol loading in a similar and positive manner. Anoxic and aerobic ammonia concentrations for systems 1 and 2 are shown in Figures 5.3 and 5.4, respectively.  After day 114, anoxic ammonia values show a gradual rise in response to increases in  leachate ammonia concentration.  Aerobic ammonia concentrations showed a slight increase as the  ammonia loading was increased and remained between 10 and 20 mg N/L.  Complete anoxic  denitrification (i.e. anoxic N O < 1 mg N/L) was reached by day 140 in System 1 and by day 130 in x  System 2. 46  5.1.4  Possible Explanations for Nitrification Failure  Operating conditions during the initial attempt at reaching the "target" leachate ammonia concentration and the second attempt were virtually identical, with the exception of the methanol loadings. Aerobic dissolved oxygen concentrations were always kept above 2 mg/L to prevent inhibition of nitrification. The addition of phosphate solutions to the systems ensured that reactor dissolved ortho-phosphate concentrations were maintained above 2 mg/L; therefore, biologically available phosphorous was not limited at any time. Similarly, pH/pump controllers maintained aerobic pH levels at approximately 7.5 by the addition of sodium bicarbonate solutions. Therefore, the failure of nitrification, or more specifically ammonia oxidation, during the initial attempt at reaching the "target" leachate ammonia concentration was thought to be the result of "free" ammonia (NH3) toxicity to the Nitrosomonas organisms that oxidize ammonia to nitrite. Anthonisen et al (1976) found that "free" ammonia concentrations of 10 to 150 mg/L could inhibit ammonia oxidation in complete mix reactors.  This section attempts to answer the obvious question as to why reactor ammonia, and "free" ammonia, concentrations, during thefirstattempt at reaching the "target" leachate ammonia concentration, increased to a point that resulted in inhibition of nitrification. As indicated earlier, the only significant difference between the first attempt and the successful second attempt was the methanol loadings. The failure or success of nitrification under rapidly increasing ammonia mass loading conditions, for the given process configuration, appears to be somewhat dependent on the denitrification process. Therefore, this section will focus on the effect of methanol loadings on process performance and possible explanations for the initial nitrification failure of the systems.  The addition of methanol to the anoxic reactors provides an organic carbon source for heterotrophic bacteria that are able to use oxidized nitrogen compounds (NO ) as electron acceptors in the absence of x  elemental oxygen. This results in the reduction of N O  x  to gaseous nitrogen compounds (e.g. N ), thus 2  providing "denitrification" of the nitrified sludge returnedfromthe clarifier. Several effects are caused by addition of organic carbon to the anoxic reactors: (1) cell synthesis by heterotrophic bacteria; (2)  47  production of alkalinity during the reduction of nitrate; and (3) removal of N O  x  from the mixed liquor  during heterotrophic energy production.  Heterotrophic Cell Synthesis The synthesis of new cellular material by heterotrophic bacteria requires nitrogen in addition to organic carbon. Bacteria can use reduced nitrogen, in the form of ammonia nitrogen, to meet this requirement (Tortora et al 1989). In a predenitrieation system such as the MLE process, raw leachate enters the anoxic reactors directly and is diluted by the return of nitrified sludge from the clarifier. However, ammonia concentrations in the anoxic reactor are still high, thus an excess amount of ammonia is available for heterotrophic cell synthesis during denitrification. Increasing the methanol loading to the anoxic reactor, providing excess N O  x  is present in the reactor, causes synthesis of more new heterotrophic cells, while  simultaneously assimilating more ammonia. Therefore, reactor solids concentrations and the amount of ammonia removal in the anoxic reactors would be expected to increase and possibly prevent rapid accumulation of ammonia in the anoxic reactors and eventually the aerobic reactors.  Figures 5.9 and 5.10 show the anoxic and aerobic volatile suspended solids concentrations (VSS) as well as the methanol loadings for systems 1 and 2, respectively. Reactor solids concentrations responded quickly to changes in methanol loading in both systems. On day 81, when the systems began receiving 1000 mg N/L ammonia leachate, the anoxic VSS in System 1 was about 3000 mg/L with an aerobic VSS concentration of 2000 mg/L. However, during the second attempt at feeding approximately 1000 mg N/L ammonia leachate at around day 126, the anoxic VSS concentration was about 4300 mg/L and around 3200 mg/L in the aerobic reactor. Similarly for System 2, anoxic VSS concentrations increased from 3300 mg/L to 3700 mg/L and aerobic VSS values went from about 2400 mg/L to 2900 mg/L. The differences in reactor VSS concentrations were probably the result of increased growth of heterotrophic denitrifying organisms, rather than increases in autotrophic nitrifying bacteria. It should be noted that when the systems were treating the "base" leachate during the recovery period between days 107 and 114, the reactor solids concentrations returned to levels (i.e. anoxic = 2800 mg/L, aerobic = 2000 mg/L) close to those that existed prior to initial increases in leachate ammonia concentration that began on day 71. 48  (P/QOO 6) Buipeon |oueinay\|  (P/QOO 6) 6ii!pe<n |oueina|/\|  The amount of ammonia removed in the anoxic reactor can be expressed in terms of the percent of ammonia removed relative to the amount of ammonia entering the anoxic reactor. These data are shown in Figures 5.11 and 5.12 for systems 1 and 2, respectively.  Between days 81 and 107, both systems  showed fluctuating ammonia removal values due to the transient state of the systems; however, usually less than 10% of ammonia entering the anoxic reactors was being removed (assimilated). This contrasts sharply with the anoxic ammonia removal after about day 112, when methanol loadings were quickly increased; up to about 30% of ammonia entering the anoxic reactors was assimilated. Once the methanol loadings were leveled off and heterotrophic growth reached steady state (as shown in almost constant reactor VSS values in Figures 5.9 and 5.10 after day 140) ammonia removal decreased rapidly from almost 30% to about 7%. Figures 5.13 and 5.14 show the actual daily mass of ammonia removed in the anoxic reactors for systems 1 and 2, and they indicate similar trends to those shown in Figures 5.11 and 5.12.  Figures 5.3 and 5.4 show that, both concentrations of ammonia in the anoxic reactors and the rate that they increased during the initial attempt (days 71 - 107) at reaching the "target" leachate ammonia concentration, were much larger than similar data during the second period of ammonia loading increments (days 114 - 138).  This appears to confirm the effect of methanol loading on anoxic  heterotrophic ammonia assimilation and the prevention of ammonia buildup that may ultimately result in "free" ammonia toxicity of ammonia oxidizing organisms.  Alkalinity Production Bicarbonate alkalinity is produced during denitrification at the theoretical rate of 3.57 mg CaC03 per mg of nitrate reduced to nitrogen gas (EPA 1993). Increasing the methanol loading to the anoxic reactors results in an increased amount of nitrate reduction (providing excess NOx is present) and, therefore, alkalinity production. The extra alkalinity results in an increase in reactor pH values. Figures 5.7 and 5.8 show the influence of methanol loading on reactor pH values for systems 1 and 2; pH values increased shortly after boosts in methanol loading; aerobic pH levels increased from 7.5 to 8.3 in System 1 and from 7.6 to 8.5 in System 2. Aerobic pH values remained constant, except during the failure period, when 51  52  53  (P/QOO ) 6U|PBOI |oueina|/\| B  (P/QOO ) 6uipeoT |oueina|/\| B  co o  10  o o  CO  c o  -§  CN  ii  (0 (0 >» ^  ;  O O  2  W T3 (0 C Q- a,  o cn  §• «  o co  «5  o r-  w E  o co  M  * .2  o in o  O) < i i .y x o c  O CO  <  o  CN  o o m co  o o o  CO  o o m CN  o o o  o o m  CN  o o o  (p/N 6ui) ajey |BAoiuay emouiuiv ojxouv  55  o o in  re Q  the pH/pump controllers were adding extra alkalinity to account for increased nitrification requirements when the leachate ammonia concentrations were increased to about 600 mg N/L.  Section 5.1.1 discussed how methanol loadings were boosted in an attempt to assimilate excess ammonia when nitrification was failing. This may have been much more damaging than helpful, in terms of restoring nitrification, because increases in methanol loading raised reactor pH values. The fraction of "total" ammonia that exists as "free" ammonia is dependent upon pH (Benefield et al 1982). Table 5.2 shows the "free" ammoniafractionrelative to "total" ammonia for various pH values (20 degrees Celsius) and illustrates the sensitivity of "free" ammonia to changes in pH. Table 5.2 "Free" Ammonia Fraction at Various pH Values  Percent of "Total" Ammonia Present as "Free" Ammonia 1.2 2.4 3.8 5.8 9.0  pH 7.5 7.8 8.0 8.2 8.4  The increase in aerobic pH levels initiated by increased methanol loadings raised the aerobic "free" ammoniafractionin System 1from1.2% to 7.2% andfrom1.5% to 11.0% in System 2. Figures 5.15 and 5.16 show the "estimated" reactor "free" ammonia concentrations and the anoxic methanol loadings. The increases in reactor pH levels resultingfromincreases in methanol loading may have been large enough to raise the "free" ammonia concentration in the aerobic reactors to the point of inhibiting ammonia oxidation by Nitrosomonas organisms. As shown in Table 5.2, a relatively small increase in pH from 7.5 to 7.8 doubles the concentration of "free" ammonia, for a given "total" ammonia concentration.  Anoxic "free" ammonia values, after about day 140, eventually reached levels higher than those present when nitrification basically "shut down" after day 103. Therefore, recycling of Nitrosomonas bacteria, contained within the clarifier return sludge, through the anoxic reactors does not appear to contribute to the inhibition of these organisms. The "free" ammonia concentrations in the aerobic reactors, although much 56  (IP/QOO 6) BuipeoT |OUBina|/\| o ^  m  °°  T  m  C  o  O  o  M  m  C  m  N  o  J  C  o  N  m  T  m  p  -  T  o  -  L  m  °° (l/N BiJufuoiiBJjuaouoo eiuouiuiv e a j J J o j O B a y  57  O  o  O  (P/QOO 6) 6u!peo-| |oueiU8i/\| O  -  m OO  LO  ^  •  o  O  r  CO  o  m  ID  c  o  CM  o  O  c  N  i  CM  LO  j  c  M  n  o T -  O  T  -  T  i T -  (l/N 6iu) uoi)ej)U33UOQ e m o u i i u v aaJJ  58  -  n  m  o  o  lower than anoxic levels, may cause the actual inhibirion to Nitrosomonas because these bacteria are "active" only in the aerobic reactors.  The combination of reaching inhibitory aerobic "free" ammonia concentrations and high ammonia mass loadings to the systems appears to have resulted in a "snowball" effect, from which recovery was not possible unless the ammonia loadings were reduced.  N O Removal x  Oxidized nitrogen compounds (NO ) that are returned to the anoxic reactors by the clarifier sludge recycle x  are used as electron acceptors by the heterotrophic denitrifying bacteria that oxidize methanol. This results in reduction of N O into gaseous nitrogen compounds that diffuse out of solution and into the x  atmosphere. Anoxic and aerobic N O values for systems 1 and 2 are shown in Figures 5.17 and 5.18, x  respectively. The low rate of methanol loading during the first attempt at reaching the "target" leachate ammonia concentration resulted in the accumulation of large amounts of N O in the reactors. This x  contrasts to the much lower values that appeared during the second attempt, when methanol loadings were increased following increases in leachate ammonia concentration (i.e. to keep pace with NOx production).  It was initially thought that high concentrations of N O in the reactors may possibly contribute to x  inhibition of nitrification.  However, a review of the literature found evidence to the contrary. A  chemostat nitrification study conducted by Gee et al (1990a) observed successful nitrification of a artificial waste containing 1000 mg N/L of ammonia, even though reactor nitrate concentrations were around 1000 mg N/L. Hunik et al (1992) found that high ionic concentrations inhibited pure cultures of Nitrosomonas europaea but specific differences were not observed between nitrite/nitrate and potassium, sodium, sulphate or chloride.  59  (P/QOO 6) Binpeon |oueiU8|/\| o  CO  o  IO  o o co o CM  O  o  o o  CO  o o  CD  o  IO  o o  CO  o  CN  o o  CO  o o in  o o  o o  o o  CN  CO  (l/N 6iu) uo|jBJjuaouoo X Q N  60  o o  (P/QOO 6) Buipeon o •  I o o co  ^  -  m  c  n  1 o o m  o  c  o  1 o o ^  in c  s  o j  C  1 o o co  |OUBIJJ8|/\| in N  t  o  T  -  1  1  o o CN  o o  (l/N 6ui) uojjBJjuaouoo X Q N  61  -  T -  m  o  1o  o  5.2  MLE Recycle Phase  This section presents and discusses data collected during the MLE Recycle Phase ( Day 159 - December 14, 1994 to Day 242 - March 7, 1995). The objective of this phase was to determine if effluent NOx concentrations could be reduced when treating the "target" leachate containing 1200 mg N/L of ammonia, while mamtaining consistent ammonia removal and stable nitrification and denitrification, by increasing the sludge recycle flow.  During the MLE Startup Phase, the sludge recycle flows were set to  approximately six times the leachate flow to maintain consistency with earlier UBC studies. Hence the recycle ratio (r) of sludge recycle flow to leachate flow was 6:1. More specifically, the recycle ratio was defined in this study as:  Recycle Ratio (r) = (Sludge Recycle Flow)/("Simulated" Leachate Flow) where: "Simulated" Leachate Flow = "base" leachate flow + NH4CI solution flow.  The earlier study by Elefsiniotis et al (1989) found an "r" of 6:1 to be optimal for identical systems treating leachate containing about 240 mg N/L of ammonia. This "r" value corresponded to actual hydraulic retentiontimes(AHRT) of 1.71, 3.42 and 1.37 hours in the anoxic reactor, aerobic reactor and clarifier, respectively.  Similarly, Azevedo (1993) used a 6:1 recycle ratio while attempting to treat  leachate containing up to 2000 mg N/L of ammonia.  During the recycle phase, "r" was set to 7:1 in System 1 and 8:1 in System 2. Increasing the sludge recycle flow decreased the AHRT in the reactors and clarifier. Table 5.3 contains the mean AHRT values, along with standard deviations, for the various reactors during the MLE Recycle Phase. The AHRT was defined as:  AHRT = (Reactor Volume)/(Total Flow through Reactor) where: Total Flow through Reactor = leachate flow + clarifier sludge recycle flow + chemical flow 62  Table 5.3 MLE Reactor Actual Hydraulic Retention Times  Reactor Anoxic Aerobic Clarifier  System #1 - r = 7:1 Mean AHRT (hr); Std. Dev. 1.61; 0.0095 3.18; 0.0186 1.27; 0.0074  System #2- r = 8:l Mean A H R T (hr); Std. Dev. 1.43; 0.0167 2.84; 0.0336 1.14; 0.0134  The very small standard deviations shown in Table 5.3 indicate the consistency of the AHRT's during the recycle phase. Mean reactor AHRT's of System 1 were found to be statistically different from those of System 2, as determined by t-tests conducted at a 5% level of significance.  These calculations are  contained in Appendix C.  The buildup of ammonia in the two systems during the MLE Recycle Phase resulted in two mitigation measures being attempted in order to ultimately reduce effluent ammonia concentrations: (1) increase in solids retentiontime(SRT); and (2) reduction in leachate ammonia concentration. The following sections separately discuss the effects that changes in SRT and leachate ammonia concentrations (i.e. ammonia mass loadings) had on reactor and effluent ammonia concentrations and reactor solids concentrations.  5.2.1  Ammonia Levels - SRT Effects  The clarifier sludge recycle flows were increased on Day 159 to provide recycle ratios of 7:1 in System 1 and 8:1 in System 2. Effluent ammonia concentrations prior to Day 159 varied between about 10 and 20 mg N/L for both systems. The residual ammonia remaining in the effluent was unexpected, given that Azevedo (1993) found that leachate containing 1500 mg N/L of ammonia could be completely nitrified (i.e. effluent ammonia < 1 mg N/L) using identical systems and a recycle ratio of 6:1. No explanation could be found for the presence of the residual ammonia; however, both systems appeared to be operating in a stable manner and it was decided to increase the recycle flows regardless of the small amount of ammonia remaining in the effluents.  63  Both systems appeared to be operating "normally" during the first two weeks after the recycle flows were increased. Aerobic SRT's were kept at 10 days. Reactor ammonia levels for System 1, shown in Figure 5.19, remained fairly constant until about day 175 when aerobic levels started to rise. Anoxic and aerobic ammonia concentrations then increased rapidly between days 186 and 189 and eventually reached about 250 mg N/L and 110 mg N/L, respectively. A similar occurrence happened, although slightly sooner, in System 2 as shown in Figure 5.20.  Between days 175 and 179, anoxic and aerobic ammonia  concentrations increased to about 200 mg N/L and 90 mg N/L, respectively.  By day 189 the anoxic  ammonia concentration was about 340 mg N/L, with an aerobic concentration of 215 mg N/L.  Elefsiniotis et al (1989) also found that nitrification became unstable after an approximate 2 week period, following increases in recycle ratio beyond 6:1. The higher reactor ammonia concentrations in System 2 compared to System 1, and also the faster accumulation of ammonia, may have been due to the shorter AHRT's of System 2. However, instability with the pH/pump controller used for System 2 resulted in pH values above the setpoint of 7.5. pH instability was due to problems with the pH probe and signal "noise" caused by the electrical motors on the mixers; therefore, the pH/pump controller was adding too much sodium bicarbonate to the reactor, thus raising the pH above the desired "actual" setpoint. Figures 5.21 and 5.22 show the reactor pH values for systems 1 and 2, respectively. Aerobic pH levels in System 1 stayed within plus or minus 0.1 units of the 7.5 setpoint. However, aerobic pH levels In System 2 were increasing between days 161 and 175. An increase in aerobic pH from 7.6 to 8.0 results in increasing the "free" ammoniafractionof "total" ammonia by 2.5 times. Therefore, "free" ammonia toxicity may have inhibited nitrification (i.e. Nitrosomonas organisms) in System 2 earlier than in System 1, Table 5.4 illustrates calculated aerobic "free" ammonia concentrations during the period of ammonia accumulation.  Anoxic "free" ammonia concentrations (Table 5.5) remained fairly constant during this period and were similar in both systems. In addition, these values are very similar to those both prior to and during the remainder of the recycle phase. Anoxic pH levels, shown in Figures 5.21 and 5.22, were similar in both systems and remained in the range of 8.3 to 8.5. Therefore, it appears that the inhibition of Nitrosomonas  64  65  66  67  68  may be dependent on "free" ammonia levels in the aerobic reactors, where the autotrophic bacteria are "active" rather than conditions within the anoxic reactor. Table 5.4 Aerobic "Free" Ammonia Concentrations  System 1 - Aerobic Free Ammonia Concentration (mg N/L) 0.1 0.2 0.3 0.6 1.4  Day  175 179 182 186 189  System 2 - Aerobic Free Ammonia Concentration (mg N/L) 0.8 1.4 2.6 4.3 3.3  Table 5.5 Anoxic "Free" Ammonia Concentrations  Day  175 179 182 186 189  System 1 - Anoxic Free Ammonia Concentration (mgN/L) 14.7 15.9 10.3 13.8 14.5  System 2 - Anoxic Free Ammonia Concentration (mg N/L) 13.9 9.3 14.7 13.8 16.0  ) In order to prevent the continued rise of reactor ammonia levels, and further inhibition of nitrification, the aerobic wasting rate was decreased from 1.0 L/d to 0.67 L/d on day 189. This resulted in an increase in aerobic SRT from 10 days to 15 days. The purpose of reducing the wasting rate was to increase the mass of nitrifying bacteria within the systems and, therefore, enable the oxidation of excess ammonia in the reactors. As shown in Figures 5.19 and 5.20, reactor ammonia concentrations quickly decreased once the wasting rate was reduced. The effect of reducing the wasting rate on reactor solids concentrations is discussed in detail in Section 5.2.2. Aerobic ammonia concentrations of about 15 mg N/L in System 1 and 40 mg N/L in System 2 were still present on day 200. Therefore, a further reduction in aerobic wasting to 0.5 L/d (SRT = 20 days) was begun on day 200, to determine if the remaining ammonia could be removed from the aerobic mixed 69  liquor and hence effluent. However, reactor ammonia levels in both systems actually increased following the further reduction in wasting rate. The average anoxic ammonia concentration between days 203 and 221, for System 1, was 177 mg N/L, with an average aerobic concentration of 58 mg N/L. For System 2, the mean anoxic and aerobic values were 156 mg N/L and 43 mg N/L, respectively.  5.2.2  Reactor Solids Levels - SRT Effects  Reactor volatile suspended solids (VSS) concentrations are shown in Figure 5.23 for System 1 and Figure 5.24 for System 2. Anoxic VSS concentrations were always higher than aerobic concentrations in both of the systems. Large diameter overflows and tubing were used between the anoxic and aerobic reactors to prevent plugging of the tubing. Plugging did not occur at any time during the study; however, there was some retention of solids in the tubing despite frequentflushing(i.e. several times a week) of the tubing using mixed liquor. The retention of solids in the tubing likely contributed to some of the differences between anoxic and aerobic concentrations, but this would be a minor contributor.  Reactor VSS concentrations are dependent on several variables including leachate ammonia concentration, anoxic methanol loading and clarifier recycle flow. Leachate ammonia concentrations, and hence ammonia mass loadings, were virtually identical for both systems and would not have contributed to significant VSS differences between the two systems. A t-test conducted on the mean ammonia mass loadings during the recycle phase determined that differences in actual ammonia loadings to the two systems were statistically insignificant (Appendix C). System 1 methanol loadings were higher than those for System 2 at the beginning of the recycle phase. As a result, System 1 had anoxic VSS concentrations that were about 1000 mg/L higher than those for System 2 during the initial period.  As expected, reactor VSS concentrations began to steadily increase when the aerobic wasting rate was reduced from 1.0 L/d to 0.67 L/d on day 189 and then to 0.5 L/d on day 200. Both systems contained similar reactor solids concentrations on day 189. Anoxic and aerobic VSS values for System 1 were about 5600 mg/L and 4100 mg/L, respectively. System 2 had an anoxic VSS concentration of 5200 mg/L and an aerobic concentration of about 4300 mg/L. Between days 189 and 221, anoxic and aerobic VSS 70  (P/QOO 6) 6u!pe<n |Oueipa|/\|  (P/QOO 6) Binpeon |oueu a|/\| T  concentrations for System 1 had increased by about 900 mg/L and 1100 mg/L, respectively. Increases of 2100 mg/L and 1900 mg/L in the anoxic and aerobic reactors, respectively, occurred during the same period in System 2.  Average methanol loadings during this period were similar for both systems and even slightly lower for System 2: 31.5 g COD/d for System 1 and 27.5 g COD/d for System 2. Hence, the greater increase in VSS levels in System 2 was probably the result of the higher rate of clarifier recycle flow. There are at least two possible explanations that support this theory. The first is based on kinetic theory that describes the performance of a completely mixed reactor with solids recycle. Reactor VSS levels can be estimated using the following equation (Mavinic 1993):  S = ((SRT * (Q + r*Q))/(V)) * ((a*(Lb - Le))/(1 + b*SRT)) where: S SRT Q r V a b Lo - Le  = reactor VSS concentration (mg/L) = solids retentiontime(d) = leachateflow(L/d) = recycle ratio = reactor volume (1) = growth yield coefficient = decay coefficient (d"*) = change in substrate concentration across reactor (mg/L)  The above equation indicates that increases in sludge recycle flow, hence recycle ratio, result in increased reactor VSS levels. The term (Lo - Le), across the aerobic reactor, will decrease in an MLE system because of additional dilution of leachate in the anoxic reactor. However, the net effect of increasing the sludge recycleflow,based on the above equation, is an increase in reactor VSS levels. Increases in sludge recycle flow decrease reactor AHRT's, therefore, a larger mass of bacteria is required to consume the same amount of substrate during the reduced time period.  Secondly, excess solids from the mixed liquor can accumulate in the bottom of the clarifiers if solids separation is highly efficient (i.e. low effluent solids concentrations) and the clarifier recycle flow is too 73  low to remove all of the accumulated solids. Therefore, assuming there was some accumulation of solids in the clarifiers, the higher recycle flow in System 2 would take a greater mass of solids out of "storage" from the clarifier and into the anoxic and aerobic reactors.  The effect of the actual mass of solids on ammonia removal efficiencies is discussed in Section 5.2.6.  5.2.3  Ammonia Levels - Ammonia Mass Loading Effects  Aerobic ammonia levels and, therefore, effluent ammonia levels in both systems were still large (i.e. > 25 mg N/L) after a period of one aerobic sludge age at an SRT of 20 days. Hence, the concentration of ammonia in the "simulated" leachate was reduced on day 221, to see if effluent ammonia concentrations could be lowered. Anoxic and aerobic ammonia concentrations in System 1 (Figure 5.19) showed an immediate decrease in response to the reduction in leachate ammonia concentration.  The ammonia  concentration of leachate being fed to System 1 was initially reduced by about 80 mg N/L. This resulted in a 40 mg N/L reduction in the aerobic ammonia concentration (i.e. 70 mg N/L to 30 mg N/L). By day 232, the leachate ammonia concentration had been reduced to about 1050 mg N/L, for a total reduction of almost 200 mg N/L.  However, aerobic ammonia levels remained fairly constant following the initial  decrease in leachate ammonia concentration on day 221, and had a mean value of 23 mg N/L between days 224 and 242.  System 2 demonstrated a similar response to the reduction in leachate ammonia  concentration. The ammonia concentration of leachate being fed to System 2 was initially reduced on day 221 by about 70 mg N/L. The aerobic ammonia concentration decreased from 25 mg N/L to 3 mg N/L. By day 232 the leachate ammonia concentration was reduced to give a total reduction of about 200 mg N/L. As with System 1, aerobic ammonia concentrations remained essentially constant after day 224, with a mean concentration of 7 mg N/L between days 224 and 242.  Between days 224 and 242, the mean anoxic ammonia concentrations for systems 1 and 2 were 151 mg N/L and 110 mg N/L, respectively. Lower anoxic ammonia concentrations in System 2 were the result of the larger recycle flow, providing more dilution of the reactor contents combined with much lower ammonia concentrations in the returned sludge (i.e. = effluent concentration) compared to System 1. 74  5.2.4  Reactor Solids Levels - Ammonia Mass Loading Effects  As indicated in Section 5.2.2, ammonia loadings to the two systems were almost identical during the recycle phase, including the period after day 221 when leachate ammonia concentrations were reduced to lower effluent ammonia concentrations. Therefore, the differing magnitude of changes is reactor VSS levels between System 1 and System 2 during this period are unlikely due to differences in ammonia loadings.  Reactor VSS concentrations would have remained constant or decreased slightly after day 221, due to the reduced ammonia loadings. However, as seen in Figures 5.23 and 5.24, reactor VSS levels were sensitive to changes in methanol loading. The sharp rise in VSS levels after day 231, particularly in System 1, were the result of large boosts in methanol loading that stimulated more growth of heterotrophic bacteria. Methanol loadings were increased in response to accumulation of NOx due to methanol shortages in the systems.  The ratio of volatile suspended solids to total suspended solids (VSS/TSS) remained fairly constant during the entire recycle phase and was in the range of 0.88 to 0.91, regardless of reactor or system.  5.2.5  Effluent Solids Levels  Figures 5.25 and 5.26 illustrate the effluent TSS and VSS levels for systems 1 and 2.  System 1  consistently had lower effluent solids concentrations, and more stable settling performance, than System 2. This is most likely the result of the longer AHRT and lower solids loading rate, due to lower aerobic SS concentrations, of System 1. This agrees with Elefsiniotis et al (1989), when using identical systems, who found that effluent solids concentrations increased considerably at recycle ratios beyond 6:1 (and thus lower clarifier AHRT's) and also resulted in more unstable clarifier performance. Interestingly, Azevedo (1993) found that effluent SS concentrations were consistently well over 100 mg/L when treating leachate containing between 1000 and 1500 mg N/L of ammonia. As shown in Figures 5.25 and 5.26, both systems used in the present study usually had less than 30 mg/L of SS in the effluents.  75  o  m CN  o I m CN  o o  c  o n  c  o  o  i  o  ^  c  o  o  o m  ^  o r  c  o o  (|/Biu) u o u e j j u a o u o o SS  77  c  o  N  o T -  o  5.2.6  Ammonia Removal  The removal of ammonia from leachate is the combined result of physical "stripping" in the aerobic reactors, bacterial assimilation, and nitrification. Ammonia "stripping" is the diffusion of unionized (i.e. gaseous) ammonia from the mixed liquor to the atmosphere.  Vigorous mixing of mixed liquor in the  aerobic reactors, caused by aeration, enhances the rate of diffusion. High pH values cause a shift in ammoniafromthe ionized form to the unionized form and, therefore, increases the amount of ammonia that could potentially be stripped. However, the short aerobic hydraulic retention times, combined with almost neutral aerobic pH levels used in this study, result in a relatively small potential for ammonia stripping. Lee and Naimie (1985) found that only 8% of ammonia could be strippedfroman aeration unit with a pH of 7.5 and a hydraulic retention time of 4 days.  Assuming that ammonia removal due to stripping is negligible, bacterial assimilation and nitrification are the main mechanisms for ammonia reduction. Section 5.2.7. respectively.  i  Nitrification performance is specifically discussed in  Figures 5.27 and 5.28 show the percent ammonia removals for systems 1 and 2, Bothfiguresshow the inhibition of nitrification that occurred between days 175 and 189. v  During this period, System 2 reactor ammonia levels (Figure 5.20) were higher than those for System 1 (Figure 5.19) and are reflected in the lower amount of aerobic and overall system ammonia removal in System 2.  Figures 5.23 and 5.24 show that the rate of increase in aerobic VSS levels between days 189 and 200 (15 d SRT) was about the same for both systems. However, after day 200 (20 d SRT), aerobic VSS levels in System 2 were increasing much more rapidly than those in System 1. Correspondingly, after day 207, aerobic ammonia removal efficiencies in System 2 (Figure 5.28) were higher than those of System 1 (Figure 5.27). The greater mass of solids in System 2 would have contained more nitrifying bacteria that, in rum, may have been able to oxidize and/or assimilate more ammonia and result in larger aerobic and system ammonia removal efficiencies and lower effluent ammonia concentrations.  The mean daily  aerobic nitrification rates (i.e. daily aerobic NOx production), between days 207 and 242, were 11090 mg N/d for System I and 11579 for System 2. The difference between these data sets was found to be 78  79  80  statistically insignificant (Appendix C), however, the data do show that, on average, System 2 produced about 4.4% more NOx than System 1. Therefore, the greater aerobic ammonia removal efficiencies of System 2 were probably the result of a combination of "extra" ammonia assimilation and oxidation.  Figures 5.27 and 5.28 show that both systems had similar anoxic ammonia removal efficiencies once nitrification had been reestablished on about day 196.  Between days 196 and 221, System 1 had a mean  anoxic ammonia removal efficiency of about 13%, with System 2 having a 16% efficiency. Similarly, the mean daily anoxic ammonia removal rates, during the same period, were 1895 mg N/d for System 1 and 1905 mg N/d for System 2. Even though the two systems had different recycle ratios, the total daily mass of NOx returned to the anoxic reactors for denitrification was approximately the same in both systems. The mean daily anoxic NOx loads for the period between days 196 and 221 were 12,400 mg N/d and 12,000 mg N/d for systems 1 and 2, respectively. Therefore, the rate of growth of heterotrophic bacteria, and thus assimilation of ammonia, should be similar in both systems. This hypothesis is confirmed by the virtually identical mean daily anoxic ammonia removal rates.  Section 5.2.3 discussed how reactor and effluent ammonia levels dropped to approximate steady state levels by day 224, after the first decrease in ammonia mass loading on day 221. System 1 had effluent ammonia concentrations of about 23 mg N/L, with System 2 concentrations around 7 mg N/L. Figures 5.27 and 5.28 show that between days 221 and 242, System 2 had anoxic ammonia removal efficiencies that were up to 2.5 times greater than those for System 1. Expectedly, a similar relationship exists with the actual daily mass of ammonia removed in the anoxic reactors. The reason for this difference is not clear, given the anoxic methanol loadings to the systems were almost equal during this period and would have resulted in similar rates of heterotrophic growth and ammonia assimilation. This higher rate of anoxic ammonia removal may have also contributed to the much lower effluent concentrations in System 2, compared to System 1.  Ammonia removal has been shown to decrease and become unstable when clarifier recycle ratios were increased to 7:1 and 8:1, from 6:1, thus reducing reactor AHRT's. 81  However, lower rates of aerobic  wasting (i.e. increased SRT's) resulted in increases in reactor solids concentrations and greater and more stable ammonia removal in both systems. As noted earlier, System 2 had slightly lower effluent ammonia concentrations than System 1, during the periodfromday 203 to 221, even though System 2 had shorter AHRT's.  However, as discussed in Section 5.2.2, System 2 had significantly higher reactor solids  concentrations during this period and presumably a larger mass of nitrifying bacteria. Therefore, the effects of decreased AHRT beyond the "critical" point (i.e. AHRT's at r = 6:1) cannot be ascertained because of the differences in reactor solids concentrations. It does appear that increases in clarifier recycle flow can increase solids concentrations and thus improve ammonia removal, possibly negating any negative effects that reduced AHRT's, caused by the increased recycle flow, may have on ammonia removal. However, the "limiting condition" for this operational approach was not explored in this study. Reductions in leachate ammonia concentration (Section 5.2.3) were also found to improve ammonia removal and result in lower effluent ammonia concentrations. Several points are noteworthy regarding the reduction of leachate ammonia concentration and its effects on effluent ammonia levels.  Leachate  ammonia concentrations in both systems were reduced by about 200 mg N/L, but System 2 had much lower effluent ammonia concentrations that System 1. As indicated in Section 5.2.3, mean aerobic (i.e. effluent) ammonia concentrations between days 224 and 242 were 23 mg N/L for System 1 and 7 mg N/L for System 2. Again, the presumed greater mass of mtrifying organisms present in System 2 are likely responsible for the lower effluent ammonia concentrations and likely offset potential negative effects of lower AHRT's.  The large reductions in leachate ammonia concentration necessary to effect significantly smaller reductions in effluent ammonia concentrations is particularly interesting. The rate of ammonium oxidation by Nitrosomonas bacteria can be described by the kinetic equation proposed by Monod (EPA 1993):  q = (q'n)*(N/(K + N)) n  n  where: 9n q' N n  ammonium oxidation rate, g NH4-N oxidized/g VSS/d maximum ammonium oxidation rate, g NH4-N oxidized/g VSS/d ammonia concentration, mg N/L half-saturation coefficient for Nitrosomonas, mg N/L 82  K  n  values (20 degrees Celsius) have been reported to vary from 0.6 to 3.6 mg N/L (EPA 1993).  Therefore, if the actual K values were at the lower end of this range, the rate of ammonium oxidation n  could be assumed to be independent of the ammonia concentration (i.e. zero-order reaction) and always proceeding at its maximum rate. This assumes that the aerobic ammonia concentrations are much larger than the "low end" K values. However, if this were the case, it would be expected that reductions in n  effluent ammonia concentrations would be closer to reductions in leachate ammonia concentration. As discussed in Section 5.2.3, both systems produced effluent containing almost constant ammonia levels, after the initial decrease (i.e. 70 to 80 mg N/L) in leachate ammonia concentration on day 221, even though the leachate ammonia concentration was eventually reduced by about 200 mg N/L. It may be that the rate of ammonia oxidation was reaching substrate limiting conditions and thus slowing down. Further reductions in leachate ammonia concentration or increases in reactor solids levels would have likely resulted in lower effluent ammonia concentrations.  5.2.7  Nitrification  The previous section discussed how ammonia removal is the combined result of bacterial assimilation of ammonia and nitrification. The % nitrification can be calculated by dividing the amount of NOx produced across the aerobic reactor by the mass of ammonia entering the aerobic reactor. Some of the ammonia entering the aerobic reactor would be assimilated by both autotrophic nitrifiers and heterotrophic bacteria feeding on organic carbon and, therefore, not available for conversion into NOx. Hence % nitrification values can be lower than the ammonia removal values presented in the previous section, and less than 100%, even when there is 100% ammonia removal. Thus, % nitrification values could be considered "conservative" in this situation.  Percent nitrification values can also be greater than 100% for several reasons, including, NOx accumulation, standard errors in sampling and analytical techniques, and the conversion (hydrolysis) of organic nitrogen in the mixed liquor to ammonia and then oxidation to NOx (Carley and Mavinic 1991). The latter can be the result of organic nitrogen originally present in the leachate and also the release of organic nitrogen from cells undergoing lysing within the system (Elefsiniotis et al 1989). Ammonia has 83  been found to make upfrom86% (Carley and Mavinic 1991) to 96% (Elefsiniotis et al 1989) of the total nitrogen in the "base" leachate used in this study. In addition, ammonium chloride was used to increase the "base" leachate ammonia concentration from about 230 mg N/L to 1200 mg N/L.  Therefore, %  nitrification values greater than 100%, that are due to the conversion of organic nitrogen, are more likely the result of organic nitrogen originatingfrombacterial cells rather than the "base" leachate itself.  Figures 5.29 and 5.30 show % nitrification data for systems 1 and 2. Expectedly, trends in % nitrification closely mimic those of aerobic ammonia removal shown in Figures 5.27 and 5.28. nitrification is evident in both systems between about days 175 and 189.  The inhibition of  System 2 had aerobic ammonia  concentrations that were up to two times as large those in System 1 and much lower % nitrification values during this period, thus indicating that nitrification inhibition in System 2 was much more severe than in System I. Nitrification was quickly restored in both systems once aerobic wasting was reduced on day 189.  Methanol shortages during the time around days 196 and 231 resulted in the accumulation of excess NOx in both systems. The "unsteady" conditions within the systems during these periods likely contributed to % nitrification values exceeding 100%, due to the effect that excess NOx has on the % nitrification calculation.  The effect that reducing leachate ammonia concentration, after day 221, had on % nitrification is difficult to determine, because of the NOx accumulation that occurred during this period. Aerobic ammonia removal in System 1 (Figure 5.27) increased from about 65% on day 221 to between 80% and 85%. However, Figure 5.29 indicates that % nitrification decreased from about 90% (day 221) to around 70% after day 235. Aerobic ammonia removal in System 2 (Figure 5.28) increased from about 80% on day 221 to around 95%. Figure 5.30 shows that % nitrification in System 2 remained at around 95% after day 235. As discussed in the previous section, higher reactor solids concentrations in System 2 likely resulted in the greater % ammonia removal and, therefore, higher % nitrification values than System 1.  84  85  o o  o m  CO  (SSA Bui/p/N Bui) a ey UOOBOUUIIN omoads T  o o  CN  CN  d  o m  o o  d  -I  — i  1  1 —  o o o  o m o d 1—  i]  o m  CN  o CN  CO CD  o  co CN  o  CN CN  o CN  o o  CN  a o  CD  Vo Nitrifica tion  ^  O CO  C> c5  Specific  j  o  ^1-  o CN  o CD  ^ >  -  •' c Cj  o  gi  o m  \  o O O  O CO  o CD  uoueoijujjN %  86  O  o CN  The specific nitrification rates of systems 1 and 2 are also shown in Figures 5.29 and 5.30. Both systems had similar rates, approximately 0.19 mg N/d/mg VSS, overall, before the clarifier recycle flows were increased on day 159. At the sametime,aerobic VSS levels were slightly higher in System 1 than System 2 during the 6:1 recycle ratio period between days 140 and 157. Fluctuations in specific nitrification rates during periods of nitrification inhibition and NOx accumulation were similar to those exhibited in % nitrification values, because the numerator in both calculations is the same. j After about day 203, once nitrification had recovered in the systems, System 1 consistently had larger specific nitrification rates than System 2. However, System 2 had aerobic VSS levels up to 1000 mg/L higher than those of System 1 after day 200, thus, resulting in expected lower specific nitrification rates. Aerobic VSS levels were increasing in both systems during this period; however, specific nitrification rates appeared to randomly fluctuate during this time. Average specific nitrification rates of 0.24 and 0.21 mg N/d/mg VSS for systems 1 and 2, respectively, occurred during the period from day 203 to 221. These values are similar to the 0.23 and 0.24 mg N/d/mg VSS values reported by Azevedo (1993) for 10 d and 20 d SRT systems, treating leachate containing 1000 mg N/L of ammonia.  As with the % nitrification data, similar difficulties exist when interpreting the specific nitrification rate data after the leachate ammonia concentrations were reduced on day 221, due to the effects that excess NOx have on the calculations.  However, by day 235, the specific nitrification rates in both systems  dropped to about 0.13 mg N/d/mg VSS. The reduction in rates is the combined result of reduced ammonia loadings to the systems and increases in aerobic VSS levels, caused by boosts in methanol loading on day 231 (to remove accumulated NOx).  Nitrification of ammonia results in the destruction of alkalinity due to production of hydrogen ions. The theoretical destruction ratio is 7.1 g CaC03 per g of ammonia-N (EPA 1993). However, denitrification produces bicarbonate alkalinity to the theoretical ratio of 3.57 g CaC03 per g of nitrate-N reduced to nitrogen gas (EPA 1975). Thus, approximately 3.5 g CaC03 are required per g ammonia-N nitrified (and subsequently denitrified). 87  Alkalinity consumption was somewhat erratic during the early stages of the recycle phase when ammonia was accumulating in the systems. Once nitrification was "stabilized", and complete denitrification restored by day 203, alkalinity consumption remained fairly constant until methanol shortages again resulted in decreased denitrification on day 231. The alkalinity consumption for System 1 ranged from 3.1 to 4.1 g CaC03 per g of ammonia-N nitrified between days 203 and 228.  System 2 required slightly more  alkalinity during this period and ranged from 3.7 to 4.3 g CaC03 per g of ammonia-N nitrified.  The total daily amount of alkalinity consumed during this period rangedfrom41.8 to 46.6 g CaC03/d for System 1 and 44.0 to 56.4 g CaC03/d for System 2. System 2 should, in theory, have consumed slightly less alkalinity than System 1, due to its larger recycle ratio and greater potential for alkalinity generation during denitrification.  However, differences in ammonia assimilation and actual NOx available for  denitrification, combined with slightly higher aerobic pH levels in System 2, appeared to have offset the potential for higher return of alkalinity in System 2. Aerobic pH levels in System 2 (Figure 5.22) were 0.1 to 0.2 units higher than levels in System I (Figure 5.21).  5.2.8  NOx Levels  Nitrification of leachate in the aerobic reactor results in the oxidation of ammonia to nitrite (NO2") and then nitrate (NO3"). "NOx" is the sum of nitrite and nitrate. Nitrified sludge from the clarifier, produced during nitrification in the aerobic reactor, is returned to the anoxic reactor for denitrification in predenitrification systems, such as the MLE process.  Figures 5.31 and 5.32 show the reactor NOx concentrations for systems 1 and 2, respectively.  Both  systems consistently removed all of the NOx entering the anoxic reactors (providing sufficient methanol was available for denitrification) regardless of recycle ratio, anoxic AHRT or solids concentration. Elevated anoxic, and thus aerobic, NOx values at around day 196 were the result of high NOx production when nitrification was restored between days 189 and 196.  Figures 5.19 and 5.20 indicated elevated  reactor ammonia concentrations during this period. Not enough methanol was available for denitrification of the excess NOx produced by nitrification of the "extra" ammonia during this period; therefore, some 88  (P/QOO ) Bujpeon lOUBqjaiAi B  (P/QOO ) BuipeoT |ouei|)3|/\| 6  oo II CN *  tn  E S> «0 <?  >. > x  a  • O a> z 8 o  Q.  a  o  o  <1) C f£ to UJ —I  2  <N  .y K  g <  a> 3  o in co  o o  CO  o  LO CM  o o  O  CM  o o  (|/N Bill) UOIJBJ1U90UOQ X Q N  90  o m  accumulation of NOx occurred in the systems. Figures 5.31 and 5.32 show that boosts in methanol loading resulted in rapid removal of excess NOx. Elevated NOx values in both systems on day 231 were also caused by methanol shortages. Reductions in NOx concentrations after day 231 were the result of reduced ammonia loadings to the systems. Aerobic, and effluent, NOx concentrations are specifically discussed in Section 5.2.10 entitled "System NOx Removal".  The oxidation of nitrite to nitrate by Nitrobacter organisms normally proceeds at a much faster rate than the oxidation of ammonia to nitrite by Nitrosomonas bacteria; therefore, nitrite accumulation usually does not occur in biological systems (EPA 1993). However,  Nitrobacter  organisms can be inhibited to a  greater extent than Nitrosomonas by several parameters, thus causing accumulation of nitrite in the system. Parameters suspected of inhibiting nitrite oxidation include "free" ammonia, nitrous acid, extreme temperatures, low concentrations of dissolved oxygen, metals, short sludge ages, high carbon loadings, and biologically available phosphorus deficiencies (Turk 1986).  Nitrite reactor concentrations are shown in Figure 5.33 for System 1 and Figure 5.34 for System 2. The ratio of aerobic nitrite to NOx concentration is also shown on these figures. System 1 had a mean NO2/NOX ratio of 0.60 during the recycle phase from day 161 to 242; System 2 had a mean value of 0.62 during the same period. This compares closely to Azevedo (1993) who found NO2/NOX ratios of 0.59 (20 d SRT) to 0.68 (10 d SRT) when treating leachate containing 1000 to 1500 mg N/L of ammonia. High anoxic ammonia concentrations and pH levels were thought to have caused high anoxic "free" ammonia concentrations that inhibited Nitrobacter organisms, as they were recycled through the anoxic reactors.  The aerobic NO2/NOX ratios were higher in both systems during the period of nitrification inhibition from about day 179 to day 196, than for most of the remaining recycle phase. Aerobic reactor "free" ammonia concentrations increased during this period of rapid ammonia accumulation, with System 2 having much larger aerobic "free" ammonia levels than System 1 (Section 5.2.1).  Anoxic "free" ammonia  concentrations remained relatively constant and similar in both systems. It appears that 91  Nitrobacter  in  oi»ey XQN/20N oiqojav  flj Q  o oo  o  CD  O  o  CN  O O  O OO  O CD  (l/N 6iu) uoi;ej)U33Uoo zott  92  O  O CN  <>!»ey XQN/30N ojqojav  System 2 were affected to a greater extent, as the difference between NO2/NOX ratios during this period and NO2/NOX ratios after day 196 were larger than differences in similar data for System 1. For System 2, the mean NO2/NOX ratio for days 179 to 196 was 0.66; for the period between days 200 and 221 it was 0.60. System 1 had average values of 0.63 and 0.59 for the same two periods, respectively. This may suggest that relatively low "free" ammonia concentrations in the aerobic reactor, compared to much higher levels in the anoxic reactor, can further inhibit  5.2.9  Nitrobacter.  Denitrification  The % denitrification occurring in the anoxic reactor can be calculated by dividing the amount of NOx removed in the anoxic reactor by the mass of NOx entering the anoxic reactor. Figures 5.35 and 5.36 show the % denitrification achieved in systems 1 and 2. Both systems were able to consistently remove virtually 100% of the NOx entering the anoxic reactors, providing sufficient methanol was available. Increases in recycle ratiofrom6:1 to 7:1 and 8:1, with the corresponding reduction in anoxic AHRT's, did not result in decreased denitrification performance.  Elefsiniotis et al (1989) found that denitrification performance became very unstable when recycle ratios in identical systems were increased beyond 6:1 and anoxic AHRT's reduced below 1.71 hours; denitrification varied between almost 0 and 100%. The present study found that stable and complete NOx removal could be achieved with anoxic AHRT's as low as 1.43 hours, with a recycle ratio of 8:1. The large fraction of nitrite in the return sludge (i.e. NO2/NOX = 0.6) may have contributed to consistent denitrification in the current study. Turk (1986) also found evidence to support this hypothesis; he found that nitrite reduction rates were 63% higher than nitrate reduction rates. Aerobic nitrite accumulation, caused by "free" ammonia inhibition of  Nitrobacter,  likely did not occur in the earlier study (Elefsiniotis  et al 1989), since the leachate being treated contained only about 250 mg N/L of ammonia.  Specific denitrification rates are also shown in Figures 5.35 and 5.36.  These rates vary in an almost  identical manner as the specific nitrification rates shown in Figures 5.29 and 5.30. The reason for the similarity is that the denitrification rate is a function of the anoxic NOx load, which, in nun is dependent 94  96  on the % nitrification. The specific nitrification rate is related to the % nitrification, since they share the same numerator. Between days 140 and 157, when both systems were operating with a recycle ratio of 6:1, the specific denitrification rate for System 1 (average of 0.25 mg N/d/mg VSS) was slightly lower than System 2 (average of 0.29 mg N/d/mg VSS), since System 1 had anoxic VSS concentrations that were about 1000 mg/L higher than those of System 2.  Between days 203 and 221, when nitrification had been restored and denitrification was 100%, both systems had specific denitrification rates of about 0.32 mg N/d/mg VSS, on average.  The specific  denitrification rates, as with the specific nitrification rates discussed earlier, displayed random fluctuations even though anoxic VSS levels were increasing during this period. By comparison, Azevedo (1993) found rates of 0.46 and 0.40 mg N/d/mg VSS, when treating leachate containing 1000 mg N/L of ammonia in systems with SRT's of 10 and 20 days.  Specific denitrification rates in both systems dropped sharply after day 231, to about 0.18 mg N/d/mg VSS.  Reductions in anoxic NOx loads resulting from reduced leachate ammonia concentrations were  partly responsible for the reduction in the specific denitrification rates. Increases in methanol loading to remove excess NOx also increased anoxic VSS levels and, therefore, also contributed to lowering the specific denitrification rates.  The denitrification of nitrified sludge returned from the clarifier to the anoxic reactor requires biodegradable organic carbon.  Heterotrophic denitrifying bacteria need organic carbon to act as an  electron donor for energy production and a carbon source for cell synthesis. The leachate used in this study contained low concentrations of biodegradable organic carbon (i.e. BOD5 < 40 mg O2/L); therefore, methanol was used as a carbon supplement. Methanol was selected because an earlier study at the University of British Columbia (Carley and Mavinic 1991) found that methanol resulted in "effective and trouble free" denitrification compared to some other organic carbon sources (e.g. glucose, brewer's yeast). Methanol is also the most commonly used external carbon source used in denitrification systems (EPA 1993). 97  The amount of organic carbon required to denitrify the return sludge can be expressed as the ratio of methanol added to the anoxic reactors, in terms of COD, divided by the amount of NOx removed (i.e. COD:NOx). The COD of the leachate is not included in this calculation because of the insignificant amount of biodegradable organic carbon contained within this particular leachate. The complete reduction of nitrate to nitrite, and then to nitrogen gas, theoretically requires 3.7 mg COD/mg NO3-N (Azevedo 1993). Nitrite reduction alone requires 2.3 mg COD/mg NO2-N.  Methanol loadings to the systems were usually slightly higher than actually required for complete denitrification, to ensure that any potential deficiencies in denitrification performance were due to the increased recycle ratios and decreased anoxic AHRT's, and not the result of carbon shortages. Methanol loadings were gradually reduced after complete denitrification was restored in both systems by day 203. Between days 203 and 228, an average COD:NOx ratio of 2.9 mg COD/mg NOx-N resulted in the removal of virtually 100% of the NOx entering the anoxic reactor in System 1. Similarly, a mean 2.7 mg COD/mg NOx-N ratio resulted in 100% anoxic NOx removal in System 2.  Further reductions in  methanol loadings caused a loss of complete denitrification in both systems on day 231, when methanol loadings were less than 2.3 mg COD/NOx-N.  The average NO2/NOX ratios for mixed liquor in the aerobic reactors (Section 5.2.8), hence return sludge, during this period was about 0.60 in both systems. Therefore, the theoretical COD:NOx requirement for denitrification can be calculated to be (3.7 mg COD/mg NO -N)(0.40) + (2.3 mg COD/mg NO -N)(0.60) 3  2  = 2.9 mg COD/mg NOx-N removed. The theoretical value compares closely to those obtained in this study. The amount of methanol required for complete denitrification in this study was found to be slightly less than the amount determined by Azevedo (1993). He found COD:NOx ratios of 3.5 mg COD/mg NOx-N were necessary to denitrify similar leachate containing 1000 mg N/L when using identical systems with recycle ratios of 6:1.  Turk and Mavinic (1986) determined methanol requirements of 2.80 mg  COD/mg NO2-N for nitrite reduction and 4.95 mg COD/mg NO3-N for nitrate reduction.  98  The higher rate of clarifier recycle flow in System 2 should theoretically require more methanol to denitrify the extra NOx returned to the anoxic reactor. However, subtle differences in system performance (i.e. ammonia assimilation and actual NOx available for denitrification) negated any notable differences in methanol requirements between the systems.  Anoxic pH levels, shown earlier in Figures 5.21 and 5.22, remained fairly constant during the recycle phase and were in the range of 8.3 to 8.5 the majority of the time in both systems. The approximate 1.0 increase above aerobic pH levels, which were maintained at about 7.5 using pH/pump controllers, was due to alkalinity production during denitrification in the anoxic reactors. Interestingly, anoxic pH levels in System 2 decreased noticeably during the period of nitrification inhibition between days 175 and 196. Reduced NOx production during this period would have reduced the amount of alkalinity returned to the anoxic mixed liquor during denitrification, thus resulting in lower pH values. Nitrification inhibition was less severe in System 1; hence anoxic pH levels were not as greatly affected.  5.2.10 System NOx Removal As indicated in the previous section, nitrified sludge from the clarifier is returned to the anoxic reactor for denitrification in the MLE process. The effluent from such systems still contains NOx because only some fraction of the nitrified sludge can be returned to the anoxic reactor. The effluent NOx concentration can be estimated using the following equation (EPA 1993):  effluent NOx (mg N/L) = (leachate ammonia, mg N/L)/(Q + r*Q)  where: Q  = leachate flow  r  = clarifier recycle ratio  Actual effluent NOx levels will be slightly lower than those estimated using the above equation because some of the leachate ammonia is assimilated by bacteria for cell synthesis and is not available for conversion into NOx. Similarly, some ammonia may be "stripped" from the leachate in the aerobic reactor and is not available for nitrification. 99  The above equation illustrates that higher rates of clarifier recycle flow, hence larger "r" values, theoretically result in lower effluent NOx concentrations, all else being equal in a well operated system. For a given leachate ammonia concentration, increasing the recycle ratio from 6:1 to 7:1 would result in a 13% reduction in effluent NOx levels; an increase from 6:1 to 8:1 would yield a 22% reduction, and so on. An 8:1 recycle ratio should produce effluent with NOx levels 11% lower than those of a 7:1 system.  The purpose of the MLE Recycle Phase was to determine if larger recycle ratios actually result in lower effluent NOx concentrations, when treating leachate containing approximately 1200 mg N/L of ammonia. However, the presence of ammonia in effluents from both systems makes this determination very difficult, since not all of the NOx that could potentially be produced was actually available for denitrification. Larger effluent ammonia concentrations result in lower effluent NOx levels, and vice versa, for a given recycle ratio.  One way to compare effluent quality of the two systems is to calculate the total amount of inorganic nitrogen in the effluents. Total inorganic nitrogen is the sum of ammonia and NOx concentrations. This calculation approximates the total amount of NOx that would be in the effluent if the residual effluent ammonia would have been converted to NOx (i.e. complete nitrification). Once complete denitrification was reestablished on day 203, and omitting data from day 231, the mean total effluent inorganic nitrogen concentration for System 1 (days 203 to 242) was 192 mg N/L; the mean value for System 2 was 171 mg N/L. The effluent nitrogen concentrations were "corrected" to account for small dilution effects caused by addition of various chemicals to the systems. Day 231 was omitted because of elevated NOx values caused by methanol shortages in both systems. A t-test conducted on the mean differences in the data (Appendix C) concluded that there was a significant difference in the amount of inorganic nitrogen contained in the effluents. A similar test (Appendix C) concluded that differences in ammonia loadings to the systems were insignificant during this period.  The results of this analysis are difficult to interpret. Figures 5.31 and 5.32 indicate that System 2 almost always had lower aerobic, hence effluent, NOx concentrations than System 1. In addition, Figures 5.19 100  and 5.20 show that, after nitrification was reestablished on day 196, System 2 usually had much lower aerobic ammonia concentrations than System 1. Higher VSS levels in System 2, compared to System 1, may have been able to assimilate a greater mass of ammonia, thus lowering the actual amount of NOx produced during nitrification and, therefore, resulting in lower effluent NOx concentrations.  A t-test  conducted on the mean differences in the anoxic NOx load data (Appendix C) concluded that there was not a significant difference in the amount of NOx entering the anoxic reactors for denitrification. Hence, the higher recycle rate used in System 2 may not have contributed directly to the lower effluent inorganic nitrogen concentrations as predicted by the above equation, but may have produced indirect benefits, through ammonia reduction and less NOx production.  Further difficulties with data interpretation become apparent when examining data prior to the period when the clarifier recycle flows were increased.  When System 1 was using a 6:1 recycle ratio and  achieving complete denitrification (days 140 to 157), the mean total effluent inorganic nitrogen concentration was 156 mg N/L. Under similar conditions (days 130 to 157), System 2 produced effluent containing a mean concentration of 140 mg N/L. Lower recycle ratios are theoretically expected to result in higher, and not lower, effluent nitrogen concentrations. Therefore, based on the above findings, no evidence exists to support the theory that increasing recycle ratios from 6:1 to 7 or 8:1 automatically results in lower effluent NOx concentrations. It appears that several operational variables are at play when using an MLE - type process to treat high ammonia wastes, to achieve maximum ammonia reductions and lowest possible NOx levels in the final effluent.  5.3  Bardenpho Phase  This section presents and discusses data collected during the Bardenpho Phase (Day 1 - March 8, 1995 to Day 31 - April 7, 1995).  The objective of this phase was to verify the ability of a pre and  postdenitrification system (i.e. 4 stage Bardenpho Process) to remove essentially 100% of the inorganic nitrogenfromleachate containing approximately 1100 mg N/L of ammonia.  101  5.3.1  System Operation  The Bardenpho Process for nitrogen removal consists of an anoxic reactor (Anoxic #1) , aerobic reactor (Aerobic #1), a second anoxic reactor (Anoxic #2), a second aerobic reactor (Aerobic #2) and then a clarifier (Figure 1.2).  Mixed liquor from Aerobic #1 was recycled to Anoxic #1 to provide a feed of  nitrates/nitrites to the "predenitrification" part of the process. The mixed liquor recycle ratio, or Aerobic #1 recycle ratio, was maintained at 4:1 for the entire Bardenpho phase. Sludge from the clarifier was also returned to Anoxic #1 to prevent the accumulation of solids in the clarifier and maintain sufficient VSS concentrations throughout the system. The clarifier sludge recycle ratio was initially set a 2:1, however, accumulation of solids in the clarifier, as indicated by therisingsludge blanket, necessitated an increase in clarifier sludge recycle flow. Therefore, the clarifier sludge recycle flow was increased on day 12 to yield a recycle ratio of 3:1. The 3:1 clarifier recycle ratio was sufficient to stop the accumulation of solids and maintain a constant sludge blanket elevation within the clarifier. The recycle ratios were defined in this phase as: Aerobic #1 Recycle Ratio = (Aerobic #1 Recycle Flow)/("Simulated" Leachate Flow) Clarifier Recycle Ratio = (Clarifier Recycle Flow)/("Simulated" Leachate Flow) where: "Simulated" Leachate Flow = "base" leachate flow + NH4CI solution flow. The recycle flows were set such that AHRT's in Anoxic #1 and Aerobic #1 were similar to those used during the MLE Recycle Phase. Table 5.6 contains the average reactor AHRT's for the periodfromday 13 to day 31 when the Aerobic #1 recycle ratio was 4:1 and clarifier recycle ratio was 3:1. Table 5.6 Bardenpho Reactor Actual Hydraulic Retention Times  Reactor Anoxic #1 Aerobic #1 Anoxic #2 Aerobic #2 Clarifier  Mean AHRT (hr) 1.64 3.17 3.25 6.34 2.54  The "post denitrification" reactors (i.e. Anoxic #2,  Aerobic #2) were the same size as their  "predenitrification" counterparts because the two, identical MLE systems were combined to form the 102  Bardenpho system. The lack of an internal recycle in the "postdenitrification" section results in much longer AHRT's compared to those in thefirstpart of the system. Aerobic #2 is normally a reaeration zone used to strip nitrogen gas from the mixed liquor prior to clarification. Thus, AHRT's in this reactor can be as low as 0.5 hr and still be effective (EPA 1993).  Wasting from Aerobic #1 was conducted at the rate of 0.5 L/d. This resulted in an Aerobic #1 SRT of 20 days and, therefore, was comparable to the wasting rate used during the latter part of MLE Recycle Phase. Similarly, a "simulated" ammonia concentration of about 1100 mg N/L was maintained during the Bardenpho Phase.  5.3.2  Solids Levels  Reactor VSS levels are shown in Figure 5.37. The effect of increasing the clarifier sludge recycle ratio from 2:1 to 3:1 on day 12 is clearly evident in Anoxic #1; VSS levels increased from about 8000 mg/L to 10000 mg/L, after the clarifier recycle flow was increased. Smaller increases in VSS concentrations also occurred in the other reactors.  Aerobic VSS levels for the Bardenpho system were comparable to those of the MLE systems. NOx and methanol loadings to Anoxic #1 were about 40% smaller than those received by the anoxic reactors of the MLE systems, due to the smaller amount of returned nitrified mixed liquor/sludge (i.e. recycle ratio of 4:1 versus 7:1 and 8:1).  However, VSS levels in Anoxic #1, after the clarifier sludge recycle flow was  increased on day 12, were about 2000 mg/L higher than anoxic levels in the MLE systems.  Section 5.2.2 discussed how differences in anoxic and aerobic VSS levels may have been partly due to retention of solids within the overflow tubing connecting the reactors. A Masterflex pump was used to pump mixed liquor from Aerobic #1 to Anoxic #2 in the Bardenpho system. Hence, the amount of solids retained within the pump tubing was extremely small. Figure 5.37 indicates that Anoxic #2 VSS levels were 700 to 1500 mg/L larger than those of Aerobic #1.  Rapid growth of heterotrophic denitrifying  bacteria within Anoxic #2 was probably responsible for the increase in VSS levels between these two 103  104  reactors. Anoxic #2 VSS levels were usually about 1300 mg/L larger than those of Aerobic #2. The difference in VSS concentrations between Anoxic #2 and Aerobic #2 may be partly due to retention of solids in the overflow tubing; however, endogenous respiration by heterotrophic bacteria in the carbon limited aerobic reactors may have also contributed to the reduction in VSS levels between anoxic and aerobic reactors.  The VSS/TSS ratios remained essentially constant in all reactors and ranged from 0.85 to 0.88. AH reactors had a mean VSS/TSS ratio of 0.86.  Effluent TSS and VSS levels are shown in Figure 5.38.  Consistent effluent solids concentrations of  between 10 and 20 mg/L were achieved once the system stabilized after the increase in clarifier recycle flow on day 12. Interestingly, similar clarifier performance was achieved with the 7:1 MLE system during the MLE Recycle Phase, even though the clarifier AHRT was 1.27 hrs versus 2.54 hrs for the Bardenpho system.  5.3.3  Ammonia Levels and Removal  Reactor ammonia levels, shown in Figure 5.39, remained relatively constant during the Bardenpho phase. Anoxic #1 levels decreased slightly after day 12, in response to the greater dilution of incoming leachate by the larger amount of clarifier sludge recycle flow.  As with the MLE systems, complete ammonia removal was not achieved in the first aerobic reactor. Aerobic #1 ammonia levels varied from about 15 mg N/L to 25 mg N/L. The amount of ammonia removal in Aerobic #1, shown in Figure 5.40, varied between about 80% and 90% during the Bardenpho phase. The ammonia levels and % ammonia removals in Aerobic #1 were very similar to those of the aerobic reactor of the 7:1 M L E system, when treating leachate also containing about 1100 mg N/L of ammonia. Both systems had virtually identical AHRT's in their respective aerobic reactors, since they shared the same "overall" recycle ratio (i.e. 4:1 + 3:1 = 7:1).  105  LO CO  o CO  CN  (0  CO  3  O CNJ  Is  re Q  m co  SS »m  c  2 §  E .S'ui 3  LO  o o  o  o oo  o  o  o  o  LO  (|/BUI) UOUBJJU80UO0 ss  106  o  o  CO  CN  co  IT)  co  Ammonia levels in Aerobic #2, and thus effluent levels, were essentially zero during the Bardenpho phase. Therefore, Aerobic #2 ammonia removal and thus system ammonia removal was 100%  Figure 5.40 shows that the % ammonia removal in Anoxic #2 was much larger than that of Anoxic #1. Part of the difference can be attributed to the way the % ammonia removal data are calculated. Figure 5.39 indicates that Anoxic #1 ammonia levels were always in excess of 120 mg N/L; Anoxic #2 ammonia levels ranged from about 10 to 20 mg N/L.  Therefore, for a given mass of ammonia removed, the  calculated % ammonia removal would be significantly different since the calculation is formulated relative to the mass of ammonia entering the reactors.  The actual daily mass of ammonia removed in the anoxic reactors, shown in Figure 5.41, is of greater interest. Ammonia removal in Anoxic #1 was much greater than that of Anoxic #2, although more erratic. Assuming the removal of ammonia in the anoxic reactors is the result of assimilation by heterotrophic denitrifying organisms, similar amounts of ammonia removal would be expected for similar amounts of denitrification. The daily NOx loads to the anoxic reactors were almost equal, after the clarifier recycle flow was increased on day 12. The mean NOx load entering Anoxic #1, between days 13 and 31, was 5260 mg N/d; Anoxic #2 was receiving an average of 5031 mg N/d. Hence, methanol loadings to the anoxic reactors were identical during this period. The actual arnount of anoxic denitrification (i.e. mg NOx-N/d removed) was also very similar between days 13 and 31 with mean values of 5093 mg N/d and 4970 mg N/d for Anoxic #1 and Anoxic #2, respectively. A t-test conducted on the mean difference in the removal rates (Appendix C) found no significant difference in the values.  A possible explanation for the large differences in ammonia removal rates may be related to the differences in the AHRT's of the anoxic reactors. The AHRT of Anoxic #2 was essentially twice as long as the AHRT for Anoxic #1.  Section 5.2.2 previously illustrated how decreases in AHRT require  increases in reactor VSS concentrations to consume the same amount of substrate. Anoxic #1 had an average VSS concentration of 9686 mg/L between days 13 and 31; the mean value for Anoxic #2 was  109  CO  to o o  CM  O O  CO  o o  CO T—  o o  o o  CM  o o o  o o  CO  o o  CO  (p/N 6ui) iBAoiuay emouiuiv oixouv  110  o o  o o  CM  O  o  7062 mg/L. Larger VSS levels in Anoxic #1, compared to those of Anoxic #2, may have caused a greater amount of ammonia assimilation.  5.3.4  Nitrification  Nitrification performance of the aerobic reactors, expressed as % nitrification, is shown in Figure 5.42. Both reactors displayedfluctuating% nitrification data, even though % ammonia removals (Figure 5.40) were relatively constant. As discussed in Section 5.2.7, % nitrification values exceeding 100% may be due to the conversion of organic nitrogen, released by lysing cells, to ammonia and then nitrified to produce additional NOx. Wasting from Aerobic #1 (0.5 L/d) yielded an Aerobic #1 SRT of 20 days. However, the system SRT (SSRT), defined by the amount of time solids spend in the entire system, had a mean value of about 71 days during the Bardenpho phase. The long SSRT may have contributed to cell lysing, release of organic nitrogen and ultimately an increase in the amount of NOx produced during nitrification of the resulting "extra" ammonia.  Figure 5.42 also shows that Aerobic #2 occasionally had much higher % nitrification values than Aerobic #1. The concentration of ammonia entering Aerobic #2 (i.e. 20 mg N/L) was much smaller than that entering Aerobic #1 (i.e. 140 mg N/L); therefore, Aerobic #2 % nitrification values would be more sensitive to the effects of any additional NOx resultingfromconversion of organic nitrogen.  Fluctuations in % nitrification in Aerobic #1 of the Bardenpho system were of similar magnitude to those of the "stabilized" MLE systems. The low aerobic AHRT in the three systems may explain the similar nitrification "instability".  The alkalinity consumed during nitrification in Aerobic #1 is also shown in Figure 5.42.  External  alkalinity addition was not required for nitrification in Aerobic #2; therefore, alkalinity consumption was not calculated for this reactor.  After the clarifier recycle flow was increased on day 12, alkalinity  consumption remained fairly constant from day 17 to 29, with values around 4.0 g CaC03 per g ammonia-N nitrified. These values are similar to those required by the MLE Systems. The Bardenpho 111  (N B/£OOBO 6) paijtniN fr HN/A»!U||BW co  CD  1  CN  LO  1  1  co  o co  LO CN  jrobic #1 Alkalin ansumption  o  <  CM  Q LO  o  <T  Aerobic #2  LO  *  c  !c o t_  r--  CD  t  < o  CO  o  CD  o  o  CN  o o  o  CO  uoueoijLuiN %  112  o  CD  o  o  CN  o  system should require less total alkalinity than MLE  systems to nitrify similar leachate, since the  Bardenpho system has a larger denitrification "potential" that, in turn, can return more alkalinity to the mixed liquor during denitrification. Comparable data between the systems were not available to verify this hypothesis.  The specific nitrification rates of the aerobic reactors are shown in Figure 5.43. Aerobic #1 values were much higher than those of Aerobic #2, because of the higher ammonia concentrations entering Aerobic #1 versus Aerobic #2 (i.e. 140 mg N/L versus 20 mg N/L). In addition, both reactors had similar VSS concentrations. Between days 13 and 31, average VSS levels of 6091 mg/L and 5713 mg/L were present in Aerobic #1 and Aerobic #2, respectively. Therefore, the mass of ammonia removed compared to the mass of solids, was much smaller in Aerobic #2 than Aerobic #1. The average specific nitrification rate for Aerobic #1, for the period from day 13 to day 31, was 0.16 mg N/d/mg VSS; the mean value for Aerobic #2 was 0.01 mg N/d/mg VSS.  5.3.5  NOx Levels and Removal  Reactor NOx concentrations are shown in Figure 5.44. Anoxic NOx concentrations were very low (i.e. < 5 mg N/L), thus indicating essentially complete denitrification of mixed liquor entering the anoxic reactors.  The presence of NOx in Aerobic #2 indicates nitrification of some of the ammonia leaving Anoxic #2. Aerobic #2 (hence effluent) NOx concentrations were in the range of 10 to 15 mg N/L. The absence of ammonia in the effluent, combined with almost complete removal of NOx, meant that the Bardenpho system removed 99% of the total inorganic nitrogen contained within the leachate. The MLE systems, by comparison, were unable to remove all of the ammonia from the leachate and produced effluents containing greater than about 150 mg N/L of total inorganic nitrogen, regardless of recycle ratio utilized in this study. Total inorganic nitrogen removal efficiencies of the MLE systems were in the range of about 80% to 90%.  113  LO  co  115  Complete NOx removal in the Bardenpho system may be attainable, if complete nitrification of the leachate occurred within Aerobic #1, thereby eliminating the production of NOx in Aerobic #2. This could likely be accomplished by increasing the AHRT of Aerobic # 1 by decreasing its recycle flow, or increasing reactor volume. However, ammonia is required by the heterotrophic denitrifying bacteria in Anoxic #2 for cell synthesis. Figure 5.39 shows differences in ammonia concentrations between Aerobic #1 and Anoxic #2 of about 4 to 5 mg N/L. Therefore, a small residual amount of ammonia in Aerobic #1 would be desirable to ensure that denitrification in Anoxic #2 was not "ammonia limited".  Reactor N 0 levels are shown in Figure 5.45. Similar to the NOx data, virtually all N 0 was removed in 2  2  the anoxic reactors. The presence of significant amounts of N 0  2  in Aerobic #1 indicates inhibition of  Nitrobacter due to recycling of these bacteria through the high "free" ammonia concentrations present in Anoxic #1. The ratio of N 0 to NOx in Aerobic #1, also shown in Figure 5.45, remained around 0.60 2  after the clarifier recycle flow was increased on day 12. Slightly larger N0 /NOx ratios before day 17 2  may be due to higher ammonia (thus "free" ammonia) concentrations present in Anoxic #1, because of less dilution of the leachate provided by the lower clarifier recycle flow. Aerobic N0 /NOx ratios of around 2  0.60 were also found in both MLE systems.  Figure 5.45 indicates that N 0 levels in Aerobic #2, and the effluent, were also very low (i.e. 1 mg N/L). 2  Aerobic #2 N0 /NOx ratios were always less than 0.09. 2  The AHRT of Aerobic #2 was twice that of  Aerobic #1; therefore, inhibitory effects on Nitrobacter may have been offset by the longer time available for nitrite oxidation. In addition, Nitrobacter may have been able to recover from their "inhibition" in the time it took the mixed liquor to travelfromAerobic #1, through Anoxic #2 and into Aerobic #2.  5.3.6  Denitrification  Denitrification performance of the anoxic reactors is shown in Figure 5.46. Percent denitrification in both anoxic reactors was greater than about 95% most of the time. More complete NOx removal (i.e. 100% denitrification) could have been attained; however, methanol loadings were "finely tuned" in order to  116  XQN/ZON ^# oiqojav  117  CO  determine minimum organic carbon requirements for denitrification.  Therefore, there were small  methanol shortages that sometimes caused residual NOx to remain in the anoxic reactors.  Methanol loadings were essentially at their minimum between days 15 and 31. During this period the mean Anoxic #1 COD.NOx requirement for basically "complete" denitrification was 3.7 mg COD/mg NOx removed; Anoxic #2 had a average requirement of 3.8 mg COD/mg NOx removed. These values are notably larger than the COD:NOx requirements determined for the MLE systems: System 1 = 2.8 mg COD/mg NOx removed; System 2 = 2.7 mg COD/mg NOx removed. Both the Bardenpho and MLE systems had NO2/NOX ratios of about 0.60 in the nitrified return sludge/mixed liquor; thus similar unit methanol demands were expected. Therefore, the higher methanol requirements for the Bardenpho system was probably related to the introduction of oxygen into the anoxic reactors. The MLE systems had nitrified sludge from the clarifiers returned to the anoxic reactors for denitrification.  The dissolved  oxygen concentration of this return sludge was close to zero, given the "anoxic" conditions that exist at the bottom of a clarifier. However, nitrified mixed liquor entering both anoxic reactors in the Bardenpho system came directly from Aerobic #1.  Dissolved oxygen concentrations in Aerobic #1 were always  maintained above 2 mg O2/L, to ensure nitrification was not inhibited. Therefore, residual oxygen originating in Aerobic #1 was entering both anoxic reactors. The dissolved oxygen concentrations in the anoxic reactors themselves were occasionally checked with a D.O. probe and always found to be < 0.3 mg 0 /L. 2  The presence of oxygen in a denitrificatipn environment has a direct impact on the heterotrophic bacteria responsible for denitrification. These bacteria have the ability to use either oxygen, nitrate or nitrite as electron acceptors in the production of energy, by means of an electron transport chain (EPA 1993). Energy production is higher (i.e. more efficient) when oxygen is the electron acceptor. Therefore, bacteria will preferentially utilize oxygen over nitrate or nitrite. This results in the consumption of methanol beyond that required to denitrify the NOx because the oxygen is utilized prior to the NOx. Hence, COD:NOx requirements would be larger than those strictly required for the reduction of NOx. In  119  addition, the larger methanol requirements, due to the presence of both oxygen and NOx, would result in higher reactor solids levels.  The specific denitrification rates for the anoxic reactors are shown in Figure 5.47. Anoxic #1 initially had larger specific denitrification rates than Anoxic #2, because Anoxic #1 NOx loads (shown in Figure 5.48) were larger than those for Anoxic #2, prior to the increase in clarifier recycle flow on day 12. In addition, Anoxic #1 VSS levels were only about 500 to 1000 mg/L greater than those of Anoxic #2 during this time. However, after day 12 anoxic NOx loads to both reactors were very similar and within about 4% of each other. Anoxic #1 VSS levels were up to about 2500 mg/L larger than those of Anoxic #2 after day 12 (Figure 5.37). Therefore, the specific denitrification rates of Anoxic #2 increased above those of Anoxic #1 between days 13 and 31. Once the anoxic NOx loads stabilized after day 20, Anoxic #1 had an average specific denitrification rate of 0.11 mg N/d/mg VSS between days 20 and 31: the mean value for Anoxic #2 was 0.15 mg N/d/mg VSS.  5.3.7  pH Levels  pH levels, shown in Figure 5.49, varied considerably between reactors.  The pH in Aerobic #1 was  maintained at approximately 7.5 by the addition of sodium bicarbonate, using a pH/pump controller. The pH in Anoxic #1 varied from 8.1 to 8.3 after the clarifier recycle flow was increased on day 12. Similar to the MLE systems (anoxic pH's of 8.3 to 8.5), the increase in pH between Aerobic #1 and Anoxic #1 was due to the return of alkalinity to the mixed liquor during denitrification in Anoxic #1. Figure 5.49 also indicates that slight pH variations in Aerobic #1, due to minor instability in the pH/pump controller, cause almost identical variations in Anoxic #1 pH levels.  The pH levels in Anoxic #2 were significantly higher than those of Anoxic #1, and rangedfrom8.8 to 9.0. Alkalinity production in both reactors would have been similar after day 12, because the amount of anoxic denitrification (i.e. mg NOx-N/d removed) occurring within the reactors was essentially identical (Section 5.3.3). However, nitrification, accompanied by the destruction of alkalinity, occurring within Aerobic #2 reduced the pH to between 7.8 and 8.1 from the higher pH's of Anoxic #2; hence, the clarifier sludge 120  co  f-  o CO  o CD  o  o CM  o o  d  d  d  T—  d  d  o CO o d  o CD o d  o o d  (SSA Bui/p/N 6ui) a j e y uoueouuaiuaa o m o a d s  121  o CM o d  o o o d  o  LO CO  O  co  LO  CN  r  r  E  CD  -t->  0) >*  O CN  ^ S  (0  Q- _ J *  Q  C  15  z LO  QQ U oo o If)  0) w  <  3  G) ii  >xic #1  E  Anoxic #2  LO  o o o  CN  O O  o o  o o o  GO  O O O CO  o o o  (p/N Bui) peo~] XQN ojxouv  122  o o o  CN  LO CO  o  CO  LO CM  O CM  >»  re Q LO  LO  o cri  co co  CD CO  ob  CM  o oo  Hd  123  co  CM  CD  1^  o 1^  returned to Anoxic #1 may have contained less alkalinity than the mixed liquor recycledfromAerobic #1. Therefore, the clarifier return sludge may have "diluted" the contents of Anoxic #1, in terms of alkalinity concentrations, resulting in lower pH levels for similar levels of denitrification.  Anoxic pH values of 8.8 have been found to result in denitrification rates that were about 25% of the maximum rate; denitrification rates at pH levels of 8.2 were found to be 60% of the maximum rate (EPA 1993). However, specific denitrification rates, discussed in the previous section, were higher for Anoxic #2 than Anoxic #1.  Therefore, the elevated pH within Anoxic #2 does not appear to have negatively  impacted denitrification performance in this particular study.  124  Chapter 6 SUMMARY, CONCLUSIONS AND RECOMMENDATIONS  6.1  Summary  The purpose of this research was to investigate the nitrogen removal capabilities of two different biological process configurations treating leachate containing up to approximately 1200 mg N/L of ammonia.  The first configuration was a predenitrification system known as the Modified Ludzack-  Ettinger (MLE) process. The MLE Startup Phase consisted of starting up two MLE systems treating "base" leachate containing about 230 mg N/L of ammonia, followed by incrementally increasing leachate ammonia concentrations to a "target" level of 1200 mg N/L. Aerobic SRT's of 13 days were used in both systems during the MLE Startup Phase. Increases in clarifier sludge recycle flows to yield recycle ratios of 7:1 (System 1) and 8:1 (System 2), from 6:1, were investigated as a means to reduce effluent NOx concentrations during the MLE Recycle Phase. Aerobic SRT's of 10 days were initially used in both systems during the MLE Recycle Phase.  A pre and postdenitrification system, known as the Bardenpho process, was the second configuration evaluated. The Bardenpho Phase examined the overall nitrogen removal capabilities of this process when treating leachate containing about 11.00 mg N/L of ammonia.  The following summarizes the results obtainedfromthe different phases of this study:  6.1.1 1.  M L E Startup Phase Both MLE systems experienced nitrification failure, during the initial attempt at reaching the "target" leachate concentration, when leachate ammonia concentrations were increased from about 800 mg N/L to 1000 mg N/L and anoxic methanol loadings were held constant at levels required for complete denitrification of the "base" (i.e. 230 mg N/L ammonia) leachate.  125  Increases in anoxic methanol loading rates, implemented in order to remove excess NOx from the anoxic reactors and thus assimilate additional ammonia, raised reactor pH levels due to the return of alkalinity from increased denitrification. Aerobic pH levels in System 1 increased from 7.5 to 8.3, resulting in an increase in the "free" ammoniafractionfrom1.2% to 7.2%.  Similarly, System 2  aerobic pH levels increased from 7.6 to 8.5 resulting in an increase in the "free" ammonia fraction from 1.5% to 11.0%. Increases in aerobic "free" ammonia concentrations appeared to have resulted in the inhibition of Nitrosomonas organisms responsible for ammonia oxidation.  The second attempt at reaching the "target" leachate ammonia concentration of 1200 mg N/L was successful in both systems. The length oftimeit took to increment the ammonia concentration from that of the "base" leachate to 1000 mg N/L was similar during both attempts. However, during the second attempt, anoxic methanol loadings were boosted at the same time leachate ammonia concentrations were increased. Anoxic ammonia removal efficiencies of up to 30% were achieved when methanol loadings were increased in similar proportions to leachate ammonia increases. Anoxic removal efficiencies were generally less than 10% during the initial attempt at reaching the "target" ammonia concentration. Increased ammonia assimilation during reduction of NOx in the anoxic reactors helped to mitigate the rapid accumulation of ammonia, and "free" ammonia, in the systems, thus preventing apparent inhibition of Nitrosomonas.  Anoxic "free" ammonia values, after the second successful attempt at reaching the "target" leachate ammonia concentration, .eventually reached levels higher than those present when nitrification basically "shut down" during the initial attempt. Therefore, recycling of Nitrosomonas bacteria, contained within the clarifier return sludge, through the anoxic reactors, does not appear to singly contribute to the inhibition of these organisms.  .2 MLE Recycle Phase Both MLE systems produced effluents containing between 10 and 20 mg N/L of ammonia when operated with a clarifier sludge recycle ratio of 6:1 and treating leachate containing approximately 126  1200 mg N/L of ammonia. Reactor and effluent ammonia levels rapidly rose in both systems approximately 2 weeks after clarifier sludge recycle ratios were increased from 6:1 to 7:1 and 8:1. Reductions in aerobic AHRT's from 3.42 hr (r = 6:1) to 3.18 hr (r = 7:1) and 2.84 hr (r = 8:1) may have caused insufficient contact time for stable nitrification. An increase in aerobic SRT from 10 days to 15 days quickly reduced ammonia levels in both systems. A further increase in aerobic SRT to 20 days did not remove the residual ammonia remaining in the effluents.  System 1 effluent  contained an average of about 60 mg N/L of ammonia; the mean ammonia concentration in effluent from System 2 was about 40 mg N/L.  2.  Reactor VSS levels, particularly aerobic, increased more rapidly in System 2 (r = 8:1) than in System 1 (r = 7:1) when the aerobic SRT's were increased from 10 to 20 days. Actual VSS concentrations were also significantly greater in System 2 compared to System 1.  Shorter reactor AHRT's in  System 2 (i.e. kinetic influences) combined with a higher clarifier recycle flow, taking a larger mass of solids out of "storage" from the clarifier and into the reactors, may have caused the difference in solids levels between the two systems.  3.  Reductions in leachate ammonia concentration by between 70 and 80 mg N/L lowered effluent ammonia concentrations in System 1 to about 20 mg N/L and 10 mg N/L in System 2. Further reductions in leachate ammonia concentrations, for a total reduction of approximately 200 mg N/L, did not reduce effluent ammonia concentrations in either system.  4.  Stable and complete (i.e. 100%) anoxic denitrification was consistently achieved, provided adequate methanol was available for denitrification, in both MLE systems regardless of recycle ratio (up to 8:1) or anoxic AHRT (as low as 1.43 hr). COD.NOx requirements for complete denitrification were found to be, on average, 2.9 mg COD/mg NOx-N for System 1 (r = 7:1) and 2.7 mg COD/mg NOxN for System 2 (r = 8:1). Aerobic NO2/NOX ratios were around 0.60 in both systems.  127  5.  System 2 (r = 8:1) effluent total inorganic nitrogen concentrations, determined using effluent ammonia and NOx data, were found to be statistically different (i.e. lower) than those of System 1 (r = 7:1). However, no statistical difference was found in the anoxic NOx loads. Therefore, lower effluent inorganic nitrogen concentrations found in System 2 may have been caused by greater assimilation of ammonia, due to higher reactor VSS levels, and less production of NOx, rather than more NOx being denitrified (as suggested by the larger recycle ratio).  6.  Systems 1 and 2, when operated with a 6:1 recycle ratio, produced effluents, containing mean total inorganic nitrogen concentrations of about 160 mg N/L and 140 mg N/L, respectively. However, when System 1 was using r = 7:1 the mean effluent total inorganic nitrogen concentration was about 190 mg N/L; an average value of about 170 mg N/L was achieved by System 2 using r = 8:1. Thus, increases in recycle ratios did not correspond to decreased effluent total inorganic nitrogen concentrations.  7.  Effluent suspended solids concentrations usually remained below 30 mg/L regardless of recycle ratio. However, shorter clarifier AHRT's associated with using a recycle ratio of 8:1 (AHRT =1.14 hr) resulted in greater instability in clarifier performance.  6.1.3 1.  Bardenpho Phase The Bardenpho System was capable of producing effluent containing < 1 mg N/L of ammonia, between about 10 and 15 mg N/L of NOx, and less than 20 mg/L of suspended solids when treating leachate containing 1100 mg N/L of ammonia. Aerobic #1 and clarifier sludge recycle ratios of 4:1 and 3:1, respectively, were used with an Aerobic #1 SRT of 20 days. Large Aerobic #2 SS levels (i.e. 6000 mg/L), combined with efficient solids separation in the clarifier, necessitated increasing the clarifier sludge recycle ratio from 2:1 to 3:1 to prevent accumulation of solids in the bottom of the clarifier.  128  2.  Aerobic #2 (hence effluent) NO2/NOX ratios were always < 0.09, even though Aerobic #1 ratios were around 0.60. An Aerobic #2 AHRT that was twice that of Aerobic #1, combined with possible "recovery"timebetween aerobic reactors, allowed Nitrobacter to more completely oxidize available nitrite.  3.  Residual NOx remaining in the effluent was the result of incomplete ammonia removal in Aerobic #1. Ammonia levels in Aerobic #1 were in the range of 15 to 20 mg N/L; however, approximately 5 mg N/L of ammonia was removed in Anoxic #2. Therefore, a small residual amount of ammonia remaining in Aerobic #1 would be desirable to ensure denitrification in Anoxic #2 was not ammonia limited.  4.  Minimum COD:NOx requirements for complete denitrification in both anoxic reactors was in the range of 3.7 to 3.8 mg COD/mg NOx-N removed. The presence of oxygen in mixed liquor entering the anoxic reactors likely caused larger COD:NOx requirements than those determined for the MLE systems.  6.2  Conclusions  The following conclusions, in response to the objectives outlined in Section 1.5, can be made:  1.  Increases in MLE clarifier recycle ratios to 7:1 and 8:1, from 6:1, resulted in higher effluent ammonia (i.e. 50 mg N/l) and total inorganic nitrogen concentrations (i.e. 180 mg N/l); ammonia and total inorganic nitrogen concentrations of < 20 mg N/l and < 160 mg N/l, respectively, were attained when clarifier recycle ratios were set at 6:1. Total inorganic nitrogen removal efficiencies rangedfrom80% to 90% at the increased clarifier recycle ratios;  2.  Increases in MLE aerobic SRT's from 10 days to 15 days restored ammonia removal "stability"; 20 day aerobic SRT's did not further remove residual ammoniafromthe effluents;  129  3.  Reductions in MLE leachate ammonia concentrations resulted in lower effluent ammonia concentrations.  However, actual reductions in leachate ammonia levels yielded much smaller  reductions in effluent ammonia levels;  4.  The Bardenpho system produced effluent containing less than 1 mg N/1 of ammonia and 15 mg N/1 of NOx; total inorganic nitrogen removal efficiencies of 99% were consistently achieved.  Recommendations  6.3  The following recommendations can be made based on results obtained from the three phases of this study:  1.  An investigation should be conducted regarding "free" ammonia toxicity of ammonia oxidizing Nitrosomonas bacteria under both anoxic and aerobic conditions, similar to those experienced in the present research. Relative "degrees" of inhibition, for given constant "free" ammonia concentrations, would be useful in the design and operation of such systems.  2.  Further research examining the treatment of high ammonia (i.e. > 1000 mg N/L) leachate using the Bardenpho Process should be conducted.  Reactor sizes, recycle rates and AHRT's should be  investigated in order to minimize reactor volumes, while maximizing ammonia and NOx removal as well as nitrite accumulation, so as to reduce methanol requirements for denitrification.  3.  The effects of reduced operating temperatures on the Bardenpho Process should be investigated. In particular, the effects of SRT and anoxic methanol loading on system performance at low temperatures should be studied.  4.  Recent landfill design and operations have resulted in leachates containing extremely high concentrations of organics (COD > 100,000 mg/L) and ammonia ( > 6,000 mg N/L) (Robinson,  130  1995). 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Denitrification Trio, Water Environment & Technology, February, pp. 50 - 54.  134  APPENDICIES  Appendix A:  Calculation Definitions  Appendix B:  Raw and Calculated Data  Appendix C:  Statistical Analyses  135  APPENDIX A CALCULATION DEFINITIONS  MLE Process Calculations Anoxic Overflow (l/d) = [(leachate flow, l/d) + (clarifier recycle flow, l/d)] + [[(NH4C1 feedflow,ml/hr) + (methanol feed flow, ml/hr) + (P04 feedflow,ml/hr)]*(24 hr/d)(l l/1000ml)]  Aerobic Overflow (l/d) = (Anoxic overflow, l/d) + [(NaHC03 flow, ml/hr)(24 hr/d)(l 1/1000ml)]  Anoxic AHRT (hr) = [(5 l)/(Anoxic overflow, l/d)](24 hr/d)  Aerobic AHRT (hr) = [(10 l)/(Aerobic overflow, l/d)](24 hr/d)  Clarifier AHRT (hr) = [(4 l)/(Aerobic overflow, l/d)](24 hr/d)  0-P04 Loading (g P/d) = [(P04 feed cone, g P/1)(P04 feedflow,ml/hr)(24 hr/d)(l l/1000ml)] + [(leachate P04 cone, mg P/l)(leachate flow, l/d)(l g/1000 mg)]  Anoxic Methanol Load (g COD/d) = (methanol feed cone, ml/l)(methanol feed flow, ml/hr)(791.5 mg CH30H/ml CH30H)(L5 mg COD/mg CH30H)(24 hr/d)(l l/1000ml)(l g/lOOOmg)  Simulated Leachate Ammonia Concentration (mg N/1) = [[(NH4C1 feed cone, g NH4C1/1)(NH4C1 feed flow, ml/hr)(24 hr/d)(l l/1000ml)(14 g N/53.5 g NH4C1)(1000 mg/g)] + [(leachate NH4 cone, mg N/l)(leachate flow, l/d)]] / [[(NH4C1 feedflow,ml/hr)(24 hr/d)(l l/1000ml)] + (leachate flow, l/d)]  Ammonia Load (g N/d) = [[(NH4C1 feed cone, g NH4C1/1)(NH4C1 feedflow,ml/hr)(24 hr/d)(l l/1000ml)(14 g N/53.5 g NH4C1)(1000 mg/g)] + [(leachate NH4 cone, mg N/l)(leachate flow, l/d)]] * (1 g/lOOOmg) 136  Anoxic NH4 Removal Rate (mg N/d) = [(NH4C1 feed cone, g NH4C1/1)(NH4C1 feed flow, ml/hr)(24 hr/d)(l l/1000ml)(14 g N/53.5 g NH4C1)(1000 mg/g)] + [(leachate NH4 cone, mg N/l)(leachate flow, l/d)] + [(Aerobic NH4 cone, mg N/l)(Clarifier Recycle Flow, l/d)] - [(Anoxic NH4 cone, mg N/l)(Anoxic Overflow, l/d)]  Aerobic NH4 Removal Rate (mg N/d) = [(Anoxic NH4 cone, mg N/l)(Anoxic Overflow, l/d)] - [(Aerobic NH4 cone, mg N/l)(Aerobic Overflow, l/d)]  % Anoxic NH4 Removal = [Anoxic NH4 Removal Rate, mg N/d] / [[(NH4C1 feed cone, g NH4C1/1)(NH4C1 feed flow, ml/hr)(24 hr/d)(l l/1000ml)(14 g N/53.5 g NH4C1)(1000 mg/g)] + [(leachate NH4 cone, mg N/f)(leachate flow, l/d)] + [(Aerobic NH4 cone, mg N/l)(Clarifier Recycle Flow, l/d)]] * 100 % j  % Aerobic NH4 Removal = [[[(Anoxic NH4 cone, mg N/l)(Anoxic Overflow, l/d)] - [(Aerobic NH4 cone, mg N/l)(Aerobic Overflow, l/d)]] / [(Anoxic NH4 cone, mg N/l)(Anoxic Overflow, l/d)]] * 100 %  % System NH4 Removal = [[(Simulated Leachate Ammonia Cone, mg N/1) - (Effluent NH4 cone, mg N/1)] / [Simulated Leachate Ammonia Cone, mg N/1]] * 100 %  Anoxic NOx Load (mg N/d) = [(Leachate flow, l/d)(Leachate NOx cone, mg N/1] + [(Clarifier recycle flow, l/d)(Aerobic NOx cone, mg N/1)]  Anoxic Denitrification Rate (mg N/d) = [Anoxic NOx Load, mg N/d)] - [(Anoxic overflow, l/d)(Anoxic NOx cone, mg N/1)]  Anoxic Specific Denitrification Rate (mg N/d/mg VSS) = [Anoxic Denitrification Rate, mg N/d] / [(Anoxic VSS cone, mg/l)(5 1)]  137  Anoxic % Denitrification = [[Anoxic Denitrification Rate, mg N/d] / [Anoxic NOx Load, mg N/d]] * 100 %  Aerobic Nitrification Rate (mg N/d) = [(Aerobic Overflow, l/d)(Aerobic NOx cone, mg N/l)] - [(Anoxic overflow, l/d)(Anoxic NOx cone, mg N/l)]  Aerobic Specific Nitrification Rate (mg N/d/mg VSS) = [Aerobic Nitrification Rate, mg N/d] / [(Aerobic VSS cone, mg/l)( 101)]  Aerobic % Nitrification = ] [Aerobic Nitrification Rate, mg N/d] / [(Anoxic overflow, l/d)(Anoxic NH4 cone, mg N/l)]] * 100%  Anoxic COD:NOx Entering (mg COD/mg NOx-N) = [(Anoxic Methanol Load, g COD/d)(1000 mg/g)] / [Anoxic NOx Load, mg N/d]  Anoxic COD:NOx Removed (mg COD/mg NOx-N) = [(Anoxic Methanol Load, g COD/d)(1000 mg/g)] / [(Anoxic NOx Load, mg N/d) - [(Anoxic overflow, l/d)(Anoxic NOx cone, mg N/l)]]  Aerobic SRT (d) = [10 1] / [Aerobic Wasting, l/d]  System SRT (d) = [(Anoxic VSS cone, mg/l)(5 1) + (Aerobic VSS cone, mg/l)(15 1)] / [(Aerobic VSS cone, mg/l)(Aerobic Wasting, l/d) + (Effluent VSS cone, mg/1)* [(Aerobic overflow, l/d) - (Clarifier recycle flow, l/d)]]  NaHC03 Load (g CaC03/d) = [(NaHC03 feed cone, g NaHC03/l)(NaHC03 feed flow, ml/hr)(24 hr/d)(l l/1000ml)(50 g CaC03/84 g NaHC03)] + [(leachate cone, mg CaC03/l)(leachate flow, l/d)(l g/1000mg)]  138  Alkalinity / NH4 Added (g CaC03/g N) = [NaHC03 load, g CaC03/d] / [Ammonia load, g N/d]  Alkalinity / NH4 Nitrified (g CaC03/g N) = [NaHC03 load, g CaC03/d] / [(Nitrification Rate, mg N/d)(l g/1000mg)]  Simulated Leachate Flow (l/d) = [Leachate flow, l/d] + [(NH4C1 feed flow, ml/hr)(24 hr/d)(l 1/1000ml)]  Chemical Flow (l/d) = [(P04 feed flow, ml/hr) + (methanol feed flow, ml/hr) + (NaHC03 feed flow, ml/hr)]*[(24 hr/d)(l l/1000ml)]  Total Flow (l/d) = [Simulated Leachate Flow, l/d] + [Chemical Flow, l/d]  Clarifier Recycle Ratio = [Clarifier recycle flow, l/d] / [Simulated Leachate Flow, l/d]  Corrected Effluent NOx Concentration (mg N/1) = [(Effluent NOx cone, mg N/l)(Total Flow, l/d)] / [Simulated Leachate Flow, Ed]  Corrected Effluent NH4 Concentration (mg N/1) = [(Effluent NH4 cone, mg N/l)(Total Flow, Ed)] / [Simulated Leachate Flow, Ed]  Total Effluent Inorganic Nitrogen (mg N/1) = [Corrected Effluent NOx Concentration, mg N/1] + [Corrected Effluent NH4 Concentration, mg N/1]  Total Inorganic Nitrogen Removal (%) = [Ammonia Load, g N/d)] - [[(Effluent NOx cone, mg N/1) + (Effluent NH4 cone, mg N/l)]*(Total Flow, l/d)(l g/1000mg)]  139  Bardenpho Process Calculations Anoxic #1 Overflow (l/d) = [(Leachate flow, l/d) + (Aerobic #1 recycle flow, l/d) + (Clarifier recycle flow, l/d)] + [[(NH4C1 feed flow, ml/hr) + (methanol #1 feed flow, ml/hr) + (P04 #1 feed flow, ml/hr)]* [(24 hr/d)(l 1/1000ml)]]  Anoxic #2 Overflow (l/d) = [Post flow, l/d] + [[(methanol #2 feed flow, ml/hr) + (P04 #2 feed flow, ml/hr)]*[(24 hr/d)(l l/1000ml)]]  Aerobic #1 Overflow (l/d) = [Anoxic #1 overflow, l/d] + [(NaHC03 #1 feed flow, ml/hr)(24 hr/d)(l 1/1000ml)]  Aerobic #2 Overflow (l/d) = [Anoxic #2 overflow, l/d]  Anoxic #1 AHRT (hr) = [(5 l)/(Anoxic #1 overflow, l/d)](24 hr/d)  Anoxic #2 AHRT (hr) = [(5 l)/(Anoxic #2 overflow, l/d)](24 hr/d)  Aerobic #1 AHRT (hr) = [(10 l)/(Aerobic #1 overflow, Vd)](24 hr/d)  Aerobic #2 AHRT (hr) = [(10 l)/(Aerobic #2 overflow, l/d)](24 hr/d)  Clarifier AHRT (hr) = [(4 l)/(Aerobic #2 overflow, l/d)](24 hr/d)  Anoxic #1 NH4 Removal Rate (mg N/d) = [(Ammonia load, g N/d)(1000 mg/g)] + [(Aerobic #1 recycle flow, l/d)(Aerobic #1 NH4 cone, mg N/l)] + [(Clarifier recycle flow, l/d)(Aerobic #2 NH4 cone, mg N/l)] - [(Anoxic #1 overflow, l/d)(Anoxic #1 NH4 cone, mg N/l)]  140  Anoxic #2 NH4 Removal Rate (mg N/d) = [(Post flow, l/d)(Aerobic #1 NH4 cone, mg N/1)] - [(Anoxic #2 overflow, l/d)(Anoxic #2 NH4 cone, mg N/1)]  Aerobic #1 NH4 Removal Rate (mg N/d) = [(Anoxic #1 overflow, l/d)(Anoxic #1 NH4 cone, mg N/1)] [(Aerobic #1 overflow, l/d)(Aerobic #1 NH4 cone, mg N/1)]  Aerobic #2 NH4 Removal Rate (mg N/d) = [(Anoxic #2 overflow, l/d)(Anoxic #2 NH4 cone, mg N/1)] [(Aerobic #2 overflow, l/d)(Aerobic #2 NH4 cone, mg N/1)]  % Anoxic #1 NH4 Removal =[[Anoxic #1 NH4 Removal Rate, mg N/d] / [(Ammonia load, g N/d)(1000 mg/g) + (Aerobic #1 recycle flow, l/d)(Aerobic #1 NH4 cone, mg N/1) + (Clarifier recycle flow, l/d)(Aerobic #2 NH4 cone, mg N/1)]] * 100 %  % Anoxic #2 NH4 Removal =[[Anoxic #2 NH4 Removal Rate, mg N/d] / [(Post flow, l/d)(Aerobic #1 NH4 cone, mg N/1)]] * 100 %  % Aerobic #1 NH4 Removal = [[(Anoxic #1 overflow, l/d)(Anoxic #1 NH4 cone, mg N/1) - (Aerobic #1 overflow, l/d)(Aerobic #1 NH4 cone, mg N/1)] / [(Anoxic #1 overflow, l/d)(Anoxic #1 NH4 cone, mg N/1)]] * 100 %  % Aerobic #2 NH4 Removal = [[(Anoxic #2 overflow, l/d)(Anoxic #2 NH4 cone, mg N/1) - (Aerobic #2 overflow, l/d)(Aerobic #2 NH4 cone, mg N/1)] / [(Anoxic #2 overflow, l/d)(Anoxic #2 NH4 cone, mg N/1)]] * 100 %  % System NH4 Removal =[ [(Simulated Leachate Ammonia Cone, mg N/1) - (Effluent NH4 cone, mg N/1)] / [Simulated Leachate Ammonia Cone, mg N/1]] * 100 %  141  Anoxic #1 NOx Load (mg N/d) = (Leachate flow, l/d)(Leachate NOx cone, mg N/l) + (Aerobic #1 recycle flow, l/d)(Aerobic #1 NOx cone, mg N/l) + (Clarifier recycle flow, l/d)(Effluent NOx cone, mg N/l)  Anoxic #2 NOx Load (mg N/d) = (Post flow, l/d)(Aerobic #1 NOx cone, mg N/l)  Anoxic #1 Denitrification Rate (mg N/d) = [Anoxic #1 NOx Load, mg N/d] - [(Anoxic #1 overflow, l/d)(Anoxic #1 NOx cone, mg N/l)]  Anoxic #2 Denitrification Rate (mg N/d) = [Anoxic #2 NOx Load, mg N/d] - [(Anoxic #2 overflow, l/d)(Anoxic #2 NOx cone, mg N/l)]  Anoxic #1 Specific Denitrification Rate (mg N/d/mg VSS) = [Anoxic #1 Denitrification Rate, mg N/d] / [(Anoxic #1 VSS cone, mg/l)(5 1)]  Anoxic #2 Specific Denitrification Rate (mg N/d/mg VSS) = [Anoxic #2 Denitrification Rate, mg N/d] / [(Anoxic #2 VSS cone, mg/l)(5 1)]  Anoxic #1 % Denitrification = [[Anoxic #1 Denitrification Rate, mg N/d] / [Anoxic #1 NOx Load, mg N/d]]* 100%  Anoxic #2 % Denitrification = [[Anoxic #2 Denitrification Rate, mg N/d] / [Anoxic #2 NOx Load, mg N/d]] * 100 %  Aerobic #1 Nitrification Rate (mg N/d) = [(Aerobic #1 overflow, l/d)(Aerobic #1 NOx cone, mg N/l)] [(Anoxic #1 overflow, l/d)(Anoxic #1 NOx cone, mg N/l)]  Aerobic #2 Nitrification Rate (mg N/d) = [(Aerobic #2 overflow, l/d)(Aerobic #2 NOx cone, mg N/l)] [(Anoxic #2 overflow, l/d)(Anoxic #2 NOx cone, mg N/l)] 142  Aerobic #1 Specific Nitrification Rate (mg N/d/mg VSS) = [Aerobic #1 Nitrification Rate, mg N/d] / [(Aerobic #1 VSS cone, mg/l)( 101)]  Aerobic #2 Specific Nitrification Rate (mg N/d/mg VSS) = [Aerobic #2 Nitrification Rate, mg N/d] / [(Aerobic #2 VSS cone, mg/l)(10 1)]  Aerobic #1 % Nitrification =[[Aerobic #1 Nitrification Rate, mg N/d] / [(Anoxic #loverflow, l/d)(Anoxic #1 NH4 cone, mg N/1)]] * 100 %  Aerobic #2 % Nitrification =[[Aerobic #2 Nitrification Rate, mg N/d] / [(Anoxic #2 overflow, l/d)(Anoxic #2 NH4 cone, mg N/1)]] * 100 %  Anoxic #1 COD:NOx Entering (mg COD/mg NOx-N) = [(Anoxic #1 Methanol Load, g COD/d)(1000 mg/g)] / [Anoxic #1 NOx Load, mg N/d]  Anoxic #2 COD:NOx Entering (mg COD/mg NOx-N) = [(Anoxic #2 Methanol Load, g COD/d)(1000 mg/g)] / [Anoxic #2 NOx Load, mg N/d]  Anoxic #1 COD:NOx Removed (mg COD/mg NOx-N) = [(Anoxic #1 Methanol Load, g COD/d)(1000 mg/g)] / [(Anoxic #1 NOx Load, mg N/d) - [(Anoxic #1 overflow, l/d)(Anoxic #1 NOx cone, mg N/1)]]  Anoxic #2 COD:NOx Removed (mg COD/mg NOx-N) = [(Anoxic #2 Methanol Load, g COD/d)(1000 mg/g)] / [(Anoxic #2 NOx Load, mg N/d) - [(Anoxic #2 overflow, l/d)(Anoxic #2 NOx cone, mg N/1)]]  Aerobic #1 SRT (d) = [10 1] / [Aerobic #1 Wasting, l/d]  143  System SRT (d) = [(Anoxic #1 VSS cone, mg/l)(5 1) + (Anoxic #2 VSS cone, mg/l)(5 1) + (Aerobic #1 VSS cone, mg/l)(101) + (Aerobic #2 VSS cone, mg/l)(l 5 1)] / [(Aerobic #1 VSS cone, mg/l)(Aerobic #1 Wasting, l/d) + (Effluent VSS cone, mg/1)* [(Aerobic #2 overflow, l/d) - (Clarifier recycle flow, l/d)]] Aerobic #1 Recycle Ratio = [Aerobic #1 recycle flow, l/d] / [Simulated Leachate flow, l/d]  Clarifier Recycle Ratio = [Clarifier recycle flow, l/d] / [Simulated Leachate flow, l/d]  144  APPENDIX B RAW AND C A L C U L A T E D DATA  MLE Startup and Recycle Phases Leachate (Influent) Data MLE System #1 MLE System #2  Bardenpho Phase Leachate (Influent) Data Bardenpho System  145  Leachate (Influent) Data  Date Jul 12/94 Jul 14/94 Jul 15/94 Jul 18/94 Jul 20/94 Jul 22/94 Jul 25/94 Jul 27/94 Aug 1/94 Aug 3/94 Aug 5/94 Aug 8/94 Aug 10/94 Aug 12/94 Aug 15/94 Aug 17/94 Aug 19/94 Aug 22/94 Aug 24/94 Aug 26/94 Aug 29/94 Aug 31/94 Sep 2/94 Sep 6/94 Sep 9/94 Sep 12/94 Sep 14/94 Sep 16/94 Sep 19/94 Sep 21/94 Sep 23/94 Sep 26/94 Sep 28/94 Sep 30/94 Oct 3/94 Oct 7/94 Oct 11/94 Oct 14/94 Oct 17/94 Oct 19/94 Oct 21/94 Oct 23/94 Oct 25/94 Oct 28/94 Nov 1/94 Nov 4/94 Nov 8/94 Nov 11/94 Nov 15/94  Day 5 7 8 11 13 15 18 20 24 26 28 31 33 35 38 40 42 45 47 49 52 54 56 60 63 66 68 70 73 75 77 80 82 84 87 91 95 98 101 103 105 107 109 112 116 119 123 126 130  NH4 (mg N/l)  NOx (mg N/l)  N02 (mg N/l)  0-P04 (mp P/l)  PH  232 -  282 276 269 322 274 273 272 260 269 253 253 260 281 295 392 338 300 278 280 273 280 266 315 253 230 262 229 217 206 266 277 337 266 246 243 238 267 249 249 259 233 195 167 149 141 115  0.6 0.4 0.4 0.4 0.3 0.3 0.8 0.3 0.4 0.3 0.5 0.4 0.3 0.2 0.8 0.2 0.1 1.3 0.2 0.2 0.6 1.6 0.5 0.2 0.2 0.3 0.2 0.1 1.3 0.5 1.1 1.2 0.7 0.8 0.6 0.5 0.9 1.6 0.3 0.5 0.3 0.3 0.3 0.3 0.4 0.3  7.6 7.6 7.6 7.7  0.1 0.1 0.0 0.4 0.0 0.0 0.1 0.0 0.0 0.0 0.0 0.1 0.4 0.1  0.63 0.39 0.41 0.37 0.35 0.34 0.55 0.69 0.42 0.60 0.79 0.46 0.36 0.83 0.63 0.75 0.91 0.74 0.82 0.82 0.59 0.89 0.87 0.89 0.96 0.91 1.03 0.99 0.06 0.81 0.69 0.79 0.38 0.77 0.70 0.86 0.72 0.85 0.57  0.0 0.0 0.0 0.1 0.0 0.1 0.1  0.62 0.59 0.47 0.42 0.41 0.30 0.24  7.7 7.6 7.5 7.5 7.4 7.3 7.3  0.1 0.3 0.0 0.1 0.3 0.0 0.3 0.0 0.1 0.5 0.1 0.1  - 146  7.7 7.7 7.7 7.8 7.7 7.7 7.7 7.7 7.7 7.6 7.6 7.6 7.6 7.5 7.6 7.7 7.6 7.7 7.7 7.6 7.7 7.7 7.6 7.6 7.5 7.6 7.6 7.6 7.6 7.6 7.6 7.6 7.6 7.5  Leachate (Influent) Data  Date Nov 18/94 Nov 22/94 Nov 25/94 Nov 29/94 Dec 2/94 Dec 6/94 Dec 9/94 Dec 12/94 Dec 16/94 Dec 20/94 Dec 23/94 Dec 27/94 Dec 30/94 Jan 3/95 Jan 6/95 Jan 10/95 Jan 13/95 Jan 17/95 Jan 20/95 Jan 24/95 Jan 27/95 Jan 31/95 Feb 3/95 Feb 7/95 Feb 10/95 Feb 14/95 Feb 17/95 Feb 21/95 Feb 24/95 Feb 28/95 Mar 3/95 Mar 7/95  Day 133 137 140 144 147 151 154 157 161 165 168 172 175 179 182 186 189 193 196 200 203 207 210 214 217 221 224 228 231 235 238 242  NH4 (mg N/l) 86 98 103 139 151 119 89 83 122 148 147 125 107 94 80 123 160 157 138 121 113 134 163 132 104 135 149 195 175 136 122 132  NOx (mg N/l) 1.1 0.3 0.6 0.2 0.3 0.2 0.2 0.2 0.2 0.4 0.3 0.2 0.2 0.5 0.7 0.2 0.3 0.2 0.3 0.3 0.3 0.2 0.5 0.2 0.2 0.3 0.3 0.4 0.2 0.3 0.3 0.2  N02 (mg-N/l) 0.1 0.1 0.1 0.1 0.0 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.1 0.0 0.0 0.0 0.0 0.0 0.1 0.1 0.1 0.0 0.0 0.1 0.0 0.1 0.0 0.1 0.0 0.0  147  0-P04 (mp P/l) 0.20 0.14 0.15 0.14 0.18 0.10 0.15 0.11 0.08 0.04 0.05 0.07 0.07 0.04 0.17 0.02 0.09 0.20 0.28 0.24 0.23 0.18 0.21 0.28 0.34 0.15 0.29 0.21 0.18 0.11 0.17 0.21  PH 7.3 7.3 7.2 7.3 7.2 7.2 7.1 7.1 7.3 7.3 7.3 7.1 7.1 6.9 6.8 7.2 7.3 7.3 7.2 7.1 7.1 7.1 7.2 7.1 7.1 7.1 7.2 7.4 7.2 7.2 7.1 7.1  Leachate (Influent) Data  Date Jul 12/94 Jul 14/94 Jul 15/94 Jul 18/94 Jul 20/94 Jul 22/94 Jul 25/94 Jul 27/94 Aug 1/94 Aug 3/94 Aug 5/94 Aug 8/94 Aug 10/94 Aug 12/94 Aug 15/94 Aug 17/94 Aug 19/94 Aug 22/94 Aug 24/94 Aug 26/94 Aug 29/94 Aug 31/94 Sep 2/94 Sep 6/94 Sep 9/94 Sep 12/94 Sep 14/94 Sep 16/94 Sep 19/94 Sep 21/94 Sep 23/94 Sep 26/94 Sep 28/94 Sep 30/94 Oct 3/94 Oct 7/94 Oct 11/94 Oct 14/94 Oct 17/94 Oct 19/94 Oct 21/94 Oct 23/94 Oct 25/94 Oct 28/94 Nov 1/94 Nov 4/94 Nov 8/94 Nov 11/94 Nov 15/94  Akalinity Day (mg CaC03/l) 5 7 8 11 1790 13 15 18 2030 20 24 2180 26 28 31 2120 33 35 38 2160 40 42 45 2260 47 49 52 54 56 60 2280 63 66 2080 68 70 73 75 77 80 82 84 2300 87 2260 91 95 98 101 2080 103 105 107 109 112 1980 116 1480 119 123 1520 126 130 1260  TSS (mg/l) 69  BOD5 (mg/l)  VSS (mg/l)  COD (mg/l)  43  63  30  79  43 499 513  89  48  37  17  466 31  71  16  565 549  52  12  596 579  30  16  32  20  438 592 549 532  43  22  417 417  37  18  445 398  34  525 509 509 493 69  33 545  25  13  35  21  148  536 457 457 360 378 429 359  Leachate (Influent) Data  Date Nov 18/94 Nov 22/94 Nov 25/94 Nov 29/94 Dec 2/94 Dec 6/94 Dec 9/94 Dec 12/94 Dec 16/94 Dec 20/94 Dec 23/94 Dec 27/94 Dec 30/94 Jan 3/95 Jan 6/95 Jan 10/95 Jan 13/95 Jan 17/95 Jan 20/95 Jan 24/95 Jan 27/95 Jan 31/95 Feb 3/95 Feb 7/95 Feb 10/95 Feb 14/95 Feb 17/95 Feb 21/95 Feb 24/95 Feb 28/95 Mar 3/95 Mar 7/95  Akalinity Day (mg CaC03/l) 133 137 1340 140 144 1520 147 1180 151 154 157 1380 161 165 1380 168 1160 172 175 750 179 182 186 1480 189 193 1370 196 200 1200 203 207 1540 210 214 1200 217 221 1460 224 228 1470 231 235 1290 238 242 1540  TSS (mg/l)  COD (mg/l)  BOD5 (mg/l)  VSS (mg/l)  41  23  47  27  53  33  38 41  61  38  54  30  28  20  46  23  42  24  27  16  36  34  18  32  43  23  34  15  33 50  41  19  19  60  33  59  31  28  30  21  149  281 313 320 288 233 200 407 303 407 289 250 205 205 260 216 250 250  356 375 291 253 272 260  MLE System #1  Date Day Jul 12/94 5 7 Jul 14/94 Jul 15/94 8 11 Jul 18/94 Jul 20/94 13 Jul 22/94 15 Jul 25/94 18 Jul 27/94 20 Aug 1/94 24 Aug 3/94 26 Aug 5/94 28 31 Aug 8/94 Aug 10/94 33 Aug 12/94 35 Aug 15/94 38 Aug 17/94 40 Aug 19/94 42 Aug 22/94 45 Aug 24/94 47 Aug 26/94 49 Aug 29/94 52 Aug 31/94 54 Sep 2/94 56 Sep 6/94 60 Sep 9/94 63 Sep 12/94 66 Sep 14/94 68 Sep 16/94 70 Sep 19/94 73 Sep 21/94 75 Sep 23/94 77 Sep 26/94 80 Sep 28/94 82 84 Sep 30/94 Oct 3/94 87 Oct 7/94 91 Oct 11/94 95 Oct 14/94 98 Oct 17/94 101 Oct 19/94 103 Oct 21/94 105 Oct 23/94 107 Oct 25/94 109 Oct 28/94 112 Nov 1/94 116 Nov 4/94 119 Nov 8/94 123 Nov 11/94 126 Nov 15/94 130  P04 Feed Flow (ml/hr) 11.3 11.4 11.4 11.7 11.4 11.6 11.4 11.4 11.7 11.5 11.5 5.8 5.2 5.6 5.7 4.6 5.2 5.4 5.0 4.6 4.9 4.8 5.0 5.1 5.1 5.1 5.0 5.2 4.9 4.8 5.2 5.2 5.5 4.8 4.7 4.4 5.0 5.5 4.9 4.7 4.9 4.9 4.9 4.9 5.1 4.8 4.9 5.2 4.9  CH30H Feed Flow (ml/hr) 0 0 0 0 0 0 0 0 0 0 0 0 0 4.7 4.2 4.1 4.5 4.0 3.8 7.0 6.7 6.8 6.9 6.9 7.1 7.0 7.3 7.4 7.5 7.1 7.1 7.7 7.3 7.5 7.4 7.5 7.6 7.7 7.5 7.8 8.0 8.0 8.1 7.9 7.8 7.6 7.6 8.5 8.2  NH4CI Feed Flow (ml/hr) 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 8.4 8.0 8.1 8.2 8.3 8.1 8.5 8.4 8.4 8.6 8.5 8.5 8.7 8.7 0.0 0.0 8.8 8.3 8.9 9.0 8.8 150  NaHC03 Feed Flow Leachate (ml/hr) (l/d) 0 0 0 9.8 • 0 9.9 0 9.8 0 9.8 0 9.8 0 9.8 0 9.8 0 9.8 0 9.9 0 9.9 0 9.9 0 9.8 0 3.9 0 10.2 0 10.1 0 10.2 0 10.2 0 10.4 0 10.4 0 10.4 0. 10.4 0 * 9.6 0 9.8 0 9.6 0 9.6 0 9.8 0 9.8 8.8 9.9 12.1 9.6 25.0 9.9 25.7 9.2 25.4 9.2 29.2 9.2 26.2 9.2 31.8 9.2 29.5 9.2 31.8 9.2 17.1 9.1 0.0 9.1 0.0 9.1 0.0 9.1 0.0 8.9 8.8 8.9 15.7 8.9 18.4 9.1 21.8 8.9 26.3 9.1  Clarifier Recycle (l/d) 59.4 59.4 59.4 59.4 60.3 60.3 61.2 63.0 63.9 63.0 63.0 63.0 63.0 62.1 63.0 62.1 61.2 61.2 61.2 61.2 61.2 61.2 61.2 62.1 60.3 59.4 60.3 59.4 59:4 59.4 59.4 59.4 59.4 59.4 59.4 60.3 60.3 58.5 58.5 58.5 57.6 58.5 58.5 57.6 57.6 57.6 56.7  Anoxic Overflow (l/d)  72.9 67.0 72.4 73.2 72.4 71.5 71.7 71.7 71.7 71.7 70.9 71.1 71.8 70.0 69.3 70.6 69.8 69.5 69.8 69.1 69.1 69.1 69.1 69.1 70.0 70.0 68.1 68.1 68.1 66.8 67.5 67.9 67.0 67.2 67.1 66.3  MLE System #1  Date Nov 18/94 Nov 22/94 Nov 25/94 Nov 29/94 Dec 2/94 Dec 6/94 Dec 9/94 Dec 12/94 Dec 16/94 Dec 20/94 Dec 23/94 Dec 27/94 Dec 30/94 Jan 3/95 Jan 6/95 Jan 10/95 Jan 13/95 Jan 17/95 Jan 20/95 Jan 24/95 Jan 27/95 Jan 31/95 Feb 3/95 Feb 7/95 Feb 10/95 Feb 14/95 Feb 17/95 Feb 21/95 Feb 24/95 Feb 28/95 Mar 3/95 Mar 7/95  Day 133 137 140 144 147 151 154 157 161 165 168 172 175 179 182 186 189 193 196 200 203 207 210 214 217 221 224 228 231 235 238 242  P04 Feed Flow (ml/hr) 4.9 5.2 4.7 5.0 5.5 4.8 5.0 4.9 5.0 5.6 4.9 5.0 5.7 4.8 5.7 4.9 5.0 5.6 5.3 5.5 5.2 5.4 5.1 5.1 5.0 5.5 5.0 5.3 5.0 5.1 5.1 5  CH30H Feed Flow (ml/hr) 8.6 8.0 8.5 8.0 8.3 8.3 8.3 8.6 8.8 8.9 9.1 8.8 9.1 8.9 9.0 8.9 9.1 9.1 8.1 8.6 9.0 8.8 8.8 9.0 8.9 9.0 8.1 7.8 7.7 7.9 7.9 8.2  NH4CI Feed Flow (ml/hr) 8.9 9.2 9.0 8.7 8.8 8.9 9.0 8.9 9.2 9.2 9.4 9.2 9.1 9.6 9.0 9.7 9.0 9.4 9.5 9.4 9.4 9.1 9.1 9.6 9.1 9.3 9.4 9.4 9.2 9.2 9.2 9.2  151  NaHC03 Feed Flow (ml/hr) 25.6 28.4 27.0 27.2 27.0 28.9 29.2 32.9 27.9 28.2 29.7 29.4 29.2 29.2 30.9 29.3 24.5 23.1 34.8 32.9 30.0 27.4 28.3 28.3 30.1 29.5 25.2 25.7 28.6 33.1 24.1 25.4  Leachate (l/d) 9.1 9.1 9.1 9.1 9.1 8.9 9.1 9.1 9.1 . 9.1 9.2 9.1 9.1 9.1 9.1 9.1 9.1 9.1 9.1 9.1 9.2 9.2 9.2 8.9 8.8 8.8 8.9 8.9 8.9 8.9 8.9 8.9  Clarifier Recycle (l/d) 56.7 56.7 56.7 63.0 62.1 62.1 62.1 62.1 65.7 64.8 64.8 64.8 64.8 64.8 64.8 64.8 64.8 64.8 64.8 64.8 65.7 65.7 65.7 65.7 65.7 64.8 65.7 65.7 65.7 64.8 64.8 64.8  Anoxic Overflow (l/d) 66.3 66.4 66.3 72.6 71.8 71.5 71.8 71.7 75.4 74.5 74.6 74.5 74.5 74.5 74.5 74.5 74.5 74.5 74.5 74.5 75.5 75.5 75.5 75.2 75.1 74.2 75.2 75.2 75.2 74.3 74.3 74.3  MLE System #1  Date Jul 12/94 Jul 14/94 Jul 15/94 Jul 18/94 Jul 20/94 Jul 22/94 Jul 25/94 Jul 27/94 Aug 1/94 Aug 3/94 Aug 5/94 Aug 8/94 Aug 10/94 Aug 12/94 Aug 15/94 Aug 17/94 Aug 19/94 Aug 22/94 Aug 24/94 Aug 26/94 Aug 29/94 Aug 31/94 Sep 2/94 Sep 6/94 Sep 9/94 Sep 12/94 Sep 14/94 Sep 16/94 Sep 19/94 Sep 21/94 Sep 23/94 Sep 26/94 Sep 28/94 Sep 30/94 Oct 3/94 Oct 7/94 Oct 11/94 Oct 14/94 Oct 17/94 Oct 19/94 Oct 21/94 Oct 23/94 Oct 25/94 Oct 28/94 Nov 1/94 Nov 4/94 Nov 8/94 Nov 11/94 Nov 15/94  Day 5 7 8 11 13 15 18 20 24 26 28 31 33 35 38 40 42 45 47 49 52 54 56 60 63 66 68 70 73 75 77 80 82 84 87 91 95 98 101 103 105 107 109 112 116 119 123 126 130  Aerobic Overflow (l/d) 69.5 69.6 69.5 69.5 70.4 70.4 71.3 73.1 74.1 73.0 73.0 72.9 67.0 72.4 73.2 72.4 71.5 71.7 71.7 71.7 71.7 70.9 71.1 71.8 70.0 69.3 70.6 70.0 69.8 70.4 69.7 69.7 69.8 69.7 69.9 70.8 70.8 68.5 68.1 68.1 66.8 67.5 68.2 67.4 67.7 67.6 67.0  Anoxic AHRT (hr)  Aerobic Wasting (l/d) 0 0 0 0 0 0 0 0 1 1 0 1 1 0 0 0 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 152  Aerobic AHRT (hr)  Clarifier AHRT (hr)  1.65 1.79 1.66 1.64 1.66 1.68 1.67 1.67 1.67 1.67 1.69 1.69 1.67 1.71 1.73 1.70 1.72 1.73 1.72 1.74 1.74 1.74 1.74 1.74 1.71 1.71 1.76 1.76  3.45 3.45 3.45 3.45 3.41 3.41 3.37 3.28 3.24 3.29 3.29 3.29 3.58 3.31 3.28 3.31 3.36 3.35 3.35 3.35 3.35 3.38 3.37 3.34 3.43 3.46 3.40 3.43 3.44 3.41 3.44 3.44 3.44 3.44 3.43 3.39 3.39 3.50 3.52  1.38 1.38 1.38 1.38 1.36 1.36 1.35 1.31 1.30 1.31 1.31 1.32 1.43 1.33 1.31 1.33 1.34 1.34 1.34 1.34 1.34 1.35 1.35 1.34 1.37 1.38 1.36 1.37 1.38 1.36 1.38 1.38 1.37 1.38 1.37 1.36 1.36 1.40 1.41  1.80 1.78 1.77 1.79 1.78 1.79 1.81  3.59 3.55 3.52 3.56 3.55 3.55 3.58  1.44 1.42 1.41 1.42 1.42 1.42 1.43  MLE System #1  Date Nov 18/94 Nov 22/94 Nov 25/94 Nov 29/94 Dec 2/94 Dec 6/94 Dec 9/94 Dec 12/94 Dec 16/94 Dec 20/94 Dec 23/94 Dec 27/94 Dec 30/94 Jan 3/95 Jan 6/95 Jan 10/95 Jan 13/95 Jan 17/95 Jan 20/95 Jan 24/95 Jan 27/95 Jan 31/95 Feb 3/95 Feb 7/95 Feb 10/95 Feb 14/95 Feb 17/95 Feb 21/95 Feb 24/95 Feb 28/95 Mar 3/95 Mar 7/95  Day 133 137 140 144 147 151 154 157 161 165 168 172 175 179 182 186 189 193 196 200 203 207 210 214 217 221 224 228 231 235 238 242  Aerobic Overflow (l/d) 67.0 67.0 67.0 73.3 72.4 72.2 72.5 72.5 76.0 75.2 75.3 75.2 75.2 75.2 75.2 75.2 75.0 75.0 75.3 75.3 76.2 76.1 76.1 75.9 75.8 74.9 75.8 75.8 75.8 75.1 74.8 74.9  Anoxic AHRT (hr) 1.81 1.81 1.81 1.65 1.67 1.68 1.67 1.67 1.59 1.61 1.61 1.61 1.61 1.61 1.61 1.61 1.61 1.61 1.61 1.61 1.59 1.59 1.59 1.60 1.60 1.62 1.60 1.60 1.60 1.62 1.62 1.62  Aerobic Wasting (l/d) 0.75 0.75 0.75 1 1 1 1 1 1 1 1 1 1 1 1 1 0.67 0.67 0.67 0.67 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5  153  Aerobic AHRT (hr) 3.58 3.58 3.58 3.27 3.31 3.32 3.31 3.31 3.16 3.19 3.19 3.19 3.19 3.19 3.19 3.19 3.20 3.20 3.19 3.19 3.15 3.15 3.15 3.16 3.17 3.20 3.17 3.17 3.16 3.20 3.21 3.21  Clarifier AHRT (hr) 1.43 1.43 1.43 1.31 1.33 1.33 1.33 1.32 1.26 1.28 1.28 1.28 1.28 1.28 1.28 1.28 1.28 1.28 1.27 1.28 1.26 1.26 1.26 1.27 1.27 1.28 1.27 1.27 1.27 1.28 1.28 1.28  MLE System #1  Date Jul 12/94 Jul 14/94 Jul 15/94 Jul 18/94 Jul 20/94 Jul 22/94 Jul 25/94 Jul 27/94 Aug 1/94 Aug 3/94 Aug 5/94 Aug 8/94 Aug 10/94 Aug 12/94 Aug 15/94 Aug 17/94 Aug 19/94 Aug 22/94 Aug 24/94 Aug 26/94 Aug 29/94 Aug 31/94 Sep 2/94 Sep 6/94 Sep 9/94 Sep 12/94 Sep 14/94 Sep 16/94 Sep 19/94 Sep 21/94 Sep 23/94 Sep 26/94 Sep 28/94 Sep 30/94 Oct 3/94 Oct 7/94 Oct 11/94 Oct 14/94 Oct 17/94 Oct 19/94 Oct 21/94 Oct 23/94 Oct 25/94 Oct 28/94 Nov 1/94 Nov 4/94 Nov 8/94 Nov 11/94 Nov 15/94  Day 5 7 8 11 13 15 18 20 24 26 28 31 33 35 38 40 42 45 47 49 52 54 56 60 63 66 68 70 73 75 77 80 82 84 87 91 95 98 101 103 105 107 109 112 116 119 123 126 130  P04 Feed Cone (g P/I) 0.692 0.692 0.692 0.675 0.675 0.675 0.672 0.672 0.656 0.656 0.656 0.644 0.644 0.644 0.644 0.644 0.644 0.536 0.536 0.536 0.536 0.536 0.536 0.539 0.539 0.875 0.875 0.875 0.875 0.865 0.865 0.865 0.865 0.865 0.865 0.865 0.902 0.902 0.902 0.902 0.902 0.902 0.911 0.911 0.911 0.911 0.911 0.842 0.842  CH30H Feed Cone (ml/I) 0 0 0 0 0 0 0 0 0 0 0 0 0 15 10 10 20 20 30 30 30 40 50 60 65 65 65 65 65 65 65 65 65 65 65 65 65 75 75 85 100 100 50 25 43 55 83 109 130  154  NH4CI Feed Cone (g NH4CL/I) 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 24 62 62 110 110 138 138 138 138 138 138 138 138 138 0 0 44 92 95 131 151  NaHC03 Feed Cone (g/i) 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 80 80 80 80 80 80 80 80 80 80 80 80 80 0 0 0 80 80 80 80 80  MLE System #1  Date Nov 18/94 Nov 22/94 Nov 25/94 Nov 29/94 Dec 2/94 Dec 6/94 Dec 9/94 Dec 12/94 Dec 16/94 Dec 20/94 Dec 23/94 Dec 27/94 Dec 30/94 Jan 3/95 Jan 6/95 Jan 10/95 Jan 13/95 Jan 17/95 Jan 20/95 Jan 24/95 Jan 27/95 Jan 31/95 Feb 3/95 Feb 7/95 Feb 10/95 Feb 14/95 Feb 17/95 Feb 21/95 Feb 24/95 Feb 28/95 Mar 3/95 Mar 7/95  Day 133 137 140 144 147 151 154 157 161 165 168 172 175 179 182 186 189 193 196 200 203 207 210 214 217 221 224 228 231 235 238 242  P04 Feed Cone (9 P/i) 0.842 0.842 0.842 1.000 1.000 1.000 1.000 1.000 1.032 1.032 1.032 1.032 0.989 0.989 0.989 0.989 0.989 0.989 0.989 0.951 0.951 0.951 0.951 0.955 0.955 0.951 0.951 0.951 0.951 0.951 0.974 0.974  CH30H Feed Cone (ml/I) 145 145 160 160 160 140 140 130 130 140 130 130 130 130 120 120 130 130 130 130 130 130 120 120 120 110 125 120 120 160 145 135  155  NH4CI Feed Cone (g NH4CL/I) 160 174 174 174 174 174 174 174 174 174 174 174 174 174 174 174 174 174 174 174 174 174 174 174 174 174 160 148 148 145 145 145  NaHC03 Feed Cone (g/i) 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80  MLE System #1  Date Jul 12/94 Jul 14/94 Jul 15/94 Jul 18/94 Jul 20/94 Jul 22/94 Jul 25/94 Jul 27/94 Aug 1/94 Aug 3/94 Aug 5/94 Aug 8/94 Aug 10/94 Aug 12/94 Aug 15/94 Aug 17/94 Aug 19/94 Aug 22/94 Aug 24/94 Aug 26/94 Aug 29/94 Aug 31/94 Sep 2/94 Sep 6/94 Sep 9/94 Sep 12/94 Sep 14/94 Sep 16/94 Sep 19/94 Sep 21/94 Sep 23/94 Sep 26/94 Sep 28/94 Sep 30/94 Oct 3/94 Oct 7/94 Oct 11/94 Oct 14/94 Oct 17/94 Oct 19/94 Oct 21/94 Oct 23/94 Oct 25/94 Oct 28/94 Nov 1/94 Nov 4/94 Nov 8/94 Nov 11/94 Nov 15/94  Day 5 7 8 11 13 15 18 20 24 26 28 31 33 35 38 40 42 45 47 49 52 54 56 60 63 66 68 70 73 75 77 80 82 84 87 91 95 98 101 103 105 107 109 112 116 119 123 126 130  0-P04 Load (g P/d) 0.196 0.193 0.189 0.192 0.187 0.187 0.190 0.188 0.185 0.096 0.088 0.091 0.090 0.080 0.087 0.077 0.074 0.067 0.072 0.070 0.070 0.075 0.074 0.116 0.114 0.118 0.113 0.109 0.109 0.116 0.121 0.107 0.101 0.098 0.115 0.127 0.113 0.109 0.111 0.106 0.113 0.112 0.116 0.109 0.111 0.108 0.101  Simulated Anoxic Leachate Methanol Ammonia Ammonia COD Load Con'c Load NaHC03 (g COD/d) (mg N/l) (g N/d) g CaC03/d) 0 0 0 282 2.79 0 0 276 2.70 269 2.64 0 322 3.16 0 0 274 2.69 0 273 2.68 0 272 2.67 260 2.57 0 0 269 2.66 253 2.50 0 2.01 253 2.48 1.20 260 1.01 1.17 281 2.87 2.57 295 2.98 2.28 392 4.00 3.25 338 3.45 5.99 300 3.12 5.73 278 2.89 7.75 280 2.91 9.83 273 2.84 280 11.80 2.69 13.15 266 2.61 12.97 315 3.02 13.52 253 2.43 13.71 230 2.25 13.89 383 3.83 13.15 533 5.38 30.66 13.15 535 5.24 33.81 14.26 763 7.70 49.19 13.52 870 8.18 48.54 13.89 1018 9.57 50.22 13.71 1113 10.47 54.20 13.89 1035 9.73 50.76 14.08 1015 9.54 57.17 16.46 1030 9.69 54.54 16.03 1016 9.56 55.52 18.90 1053 9.80 38.49 22.80 1053 9.81 11.54 1053 9.81 11.54 259 2.36 5.63 233 2.07 457 9.56 4.17 23.24 11.91 690 6.28 31.13 17.98 716 6.67 34.88 26.41 950 8.66 38.47 30.38 1009 9.39 41.55 156  Anoxic ORF (mV)  -65 -51 -49 -57 -72 -98 -119 -120 -125 -132 -130 -139 -166 -155 -128 -125 -200 -162 -127 -117 -95 -109 -123 -148 -163 -127 -138 -249 -113 -103 -98 -132 -158 -164  MLE System #1  Date Nov 18/94 Nov 22/94 Nov 25/94 Nov 29/94 Dec 2/94 Dec 6/94 Dec 9/94 Dec 12/94 Dec 16/94 Dec 20/94 Dec 23/94 Dec 27/94 Dec 30/94 Jan 3/95 Jan 6/95 Jan 10/95 Jan 13/95 Jan 17/95 Jan 20/95 Jan 24/95 Jan 27/95 Jan 31/95 Feb 3/95 Feb 7/95 Feb 10/95 Feb 14/95 Feb 17/95 Feb 21/95 Feb 24/95 Feb 28/95 Mar 3/95 Mar 7/95  Day 133 137 140 144 147 151 154 157 161 165 168 172 175 179 182 186 189 193 196 200 203 207 210 214 217 221 224 228 231 235 238 242  0-P04 Load (g P/d) 0.101 0.106 0.096 0.121 0.134 0.116 0.121 0.119 0.125 0.139 0.122 0.124 0.136 0.114 0.137 0.116 0.119 0.135 0.128 0.128 0.121 0.125 0.118 0.119 0.118 0.127 0.117 0.123 0.116 0.117 0.121 0.119  Simulated Anoxic Leachate Methanol Ammonia Ammonia NaHC03 COD Load Con'c Load (g COD/d) (mg N/l) (g N/d) g CaC03/d) 35.54 1044 9.73 40.75 33.06 1174 10.94 44.68 10.77 38.76 1156 43.08 10.77 44.95 36.48 1157 10.99 37.85 1180 44.72 1183 10.78 43.56 33.12 33.12 1143 10.64 44.14 1125 10.48 50.20 31.86 32.60 1198 44.48 11.16 35.51 1223 11.40 44.82 33.72 1233 11.62 46.67 32.60 1201 44.19 11.19 33.72 1172 10.92 43.96 32.97 1216 11.35 40.23 30.78 1134 10.56 42.17 30.44 1256 11.72 46.99 33.72 1212 11.29 41.50 33.72 1255 11.70 38.89 1247 11.64 52.28 30.01 31.86 1220 11.37 48.56 33.35 1200 45.36 11.31 32.60 1187 11.18 45.51 30.10 1215 11.44 46.54 30.78 1278 11.66 43.06 30.44 1204 10.86 44.99 28.22 1258 11.35 46.60 28.86 1180 10.77 41.82 26.68 1148 10.47 42.48 26.33 1108 10.11 45.80 36.02 1051 9.59 49.35 32.65 1038 9.46 39.05 31.55 1047 9.55 42.76  157  Anoxic ORf (mV) -190 -192 -249 -212 -208 -242 -250 -242 -243 -249 -261 -258 -255 -235 -237 -248 -255 -255 -217 -227 -252 -248 -238 -254 -252 -238 -251 -213 -202 -260 -274 -285  MLE System #1  Date Jul 12/94 Jul 14/94 Jul 15/94 Jul 18/94 Jul 20/94 Jul 22/94 Jul 25/94 Jul 27/94 Aug 1/94 Aug 3/94 Aug 5/94 Aug 8/94 Aug 10/94 Aug 12/94 Aug 15/94 Aug 17/94 Aug 19/94 Aug 22/94 Aug 24/94 Aug 26/94 Aug 29/94 Aug 31/94 Sep 2/94 Sep 6/94 Sep 9/94 Sep 12/94 Sep 14/94 Sep 16/94 Sep 19/94 Sep 21/94 Sep 23/94 Sep 26/94 Sep 28/94 Sep 30/94 Oct 3/94 Oct 7/94 Oct 11/94 Oct 14/94 Oct 17/94 Oct 19/94 Oct 21/94 Oct 23/94 Oct 25/94 Oct 28/94 Nov 1/94 Nov 4/94 Nov 8/94 Nov 11/94 Nov 15/94  Day 5 7 8 11 13 15 18 20 24 26 28 31 33 35 38 40 42 45 47 49 52 54 56 60 63 66 68 70 73 75 77 80 82 84 87 91 95 98 101 103 105 107 109 112 116 119 123 126 130  Anoxic PH  7.6 7.6 7.6 7.6 7.6 7.6 7.6 7.7 7.8 7.9 8.0 8.1 8.1 8.1 8.1 7.9 7.7 7.8 7.7 7.9 8.0 8.0 7.8 7.8 7.9 7.9 7.9 7.9 8.0 8.2 7.6 7.6 7.9 7.8 7.9 8.0  Aerobic DO. (mg/l) 3.8 3.5 3.2 1.9 3.0 4.5 4.1 4.2 5.1 6.2 6.5 4.9 5.5 6.7 2.4 2.1 2.8 3.0 3.1 3.0 2.6 2.9 2.2 3.0 3.8 3.8 3.2 1.1 1.4 4.9 3.1 3.6 2.8 2.4 2.5 2.5 2.2 2.4 3.7 4.9 6.8 4.7 3.1 2.0 1.4 2.2 1.6  Aerobic pH  Anoxic Anoxic Free Aerobic \erobic Fre Ammonia NH4 NH4 Ammonia (mg N/l) (mg N/l) (mg N/l) (mg N/l) 32  7.5 7.5 7.4 7.5 7.4 7.5 7.7 7.6 7.5 7.4 7.7 7.7 7.5 7.5 7.5 7.5 7.6 7.7 7.8 7.8 7.9 8.1 8.0 8.1 8.1 7.6 7.5 7.6 7.4 7.5 7.5 7.5 7.5 7.5 7.6 7.5 7.6 7.8 8.1 8.3 7.5 7.4 7.4 7.4 7.4 7.3 158  51 21 58 48 52 48 46 41 40 39 36 35 40 33 29 50 67 66 93 99 153 208 195 209 174 164 214 320 507 293 37 58 97 80 95 110  0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.8 0.3 0.9 0.7 0.8 0.7 0.7 0.8 1.0 1.2 1.4 1.6 1.9 1.6 1.4 1.5 1.3 1.6 1.8 3.0 5.8 7.8 4.7 5.0 5.2 4.9 6.5 9.7 19.1 17.1 0.6 0.9 2.9 1.9 2.9 4.1  3 1 1 1 1 4 12 13 2 1 14 1 16 6 1 1 0 0 0 0 0 0 0 0 0 0 0 0 1 0 31 53 50 105 62 59 119 245 448 276 5 1 18 0 0 0  0.0 0.0 0.0 0.0 0.0 0.0 0.2 0.2 0.0 0.0 0.3 0.0 0.2 0.1 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 0.4 0.6 0.6 1.3 1.0 0.7 1.8 5.9 21.0 20.0 0.1 0.0 0.2 0.0 0.0 0.0  MLE System #1  Date Nov 18/94 Nov 22/94 Nov 25/94 Nov 29/94 Dec 2/94 Dec 6/94 Dec 9/94 Dec 12/94 Dec 16/94 Dec 20/94 Dec 23/94 Dec 27/94 Dec 30/94 Jan 3/95 Jan 6/95 Jan 10/95 Jan 13/95 Jan 17/95 Jan 20/95 Jan 24/95 Jan 27/95 Jan 31/95 Feb 3/95 Feb 7/95 Feb 10/95 Feb 14/95 Feb 17/95 Feb 21/95 Feb 24/95 Feb 28/95 Mar 3/95 Mar 7/95  Day 133 137 140 144 147 151 154 157 161 165 168 172 175 179 182 186 189 193 196 200 203 207 210 214 217 221 224 228 231 235 238 242  Anoxic pH 8.1 8.2 8.2 8.3 8.2 8.4 8.4 8.4 8.5 8.5 8.4 8.4 8.5 8.5 8.3 8.4 8.2 8.3 8.4 8.4 8.4 8.3 8.4 8.3 8.3 8.4 8.3 8.4 8.2 8.3 8.3 8.3  Aerobic DO. (mg/l) 2.2 3.4 3.2 3.9 4.1 4.3 4.1 4.9 3.3 4.5 3.6 3.5 4.6 4.3 4.3 3.0 3.5 3.7 4.0 3.8 3.3 2.8 2.7 2.4 2.3 2.4 2.7 3.0 2.3 2.9 2.6 3.3  Aerobic pH 7.3 7.4 7.4 7.5 7.4 7.5 7.4 7.5 7.5 7.5 7.5 7.5 7.5 7.4 7.5 7.6 7.5 7.5 7.6 7.4 7.4 7.4 7.5 7.4 7.4 7.4 7.5 7.4 7.3 7.5 7.5 7.5  159  Anoxic Anoxic Free Aerobic \erobic Fret Ammonia NH4 Ammonia NH4 (mg N/l) (mg N/l) (mg N/l) (mg N/l) 116 5.4 1 0.0 20 0.2 131 7.7 7.4 12 0.1 127 16 0.2 155 11.2 17 0.2 156 9.1 0.2 155 13.9 19 14 0.1 148 13.3 10 0.1 123 11.0 12.8 8 0.1 116 16.5 9 0.1 150 9 0.1 146 13.1 12.2 4 0.0 136 14.7 7 0.1 133 15.9 18 0.2 144 26 0.3 142 10.3 37 0.6 154 13.8 111 1.4 248 14.5 13.8 69 0.8 190 139 12.4 18 0.3 12.4 14 0.1 139 0.3 153 13.7 30 181 13.1 61 0.6 186 16.7 65 0.8 0.6 178 12.9 62 12.4 56 0.5 171 191 17.1 71 0.7 0.4 157 11.4 30 167 15.0 12 0.1 149 8.7 29 0.2 19 0.2 144 10.4 29 0.4 146 10.6 140 10.1 21 0.3  MLE System #1  Date Jul 12/94 Jul 14/94 Jul 15/94 Jul 18/94 Jul 20/94 Jul 22/94 Jul 25/94 Jul 27/94 Aug 1/94 Aug 3/94 Aug 5/94 Aug 8/94 Aug 10/94 Aug 12/94 Aug 15/94 Aug 17/94 Aug 19/94 Aug 22/94 Aug 24/94 Aug 26/94 Aug 29/94 Aug 31/94 Sep 2/94 Sep 6/94 Sep 9/94 Sep 12/94 Sep 14/94 Sep 16/94 Sep 19/94 Sep 21/94 Sep 23/94 Sep 26/94 Sep 28/94 Sep 30/94 Oct 3/94 Oct 7/94 Oct 11/94 Oct 14/94 Oct 17/94 Oct 19/94 Oct 21/94 Oct 23/94 Oct 25/94 Oct 28/94 Nov 1/94 Nov 4/94 Nov 8/94 Nov 11/94 Nov 15/94  Day 5 7 8 11 13 15 18 20 24 26 28 31 33 35 38 40 42 45 47 49 52 54 56 60 63 66 68 70 73 75 77 80 82 84 87 91 95 98 101 103 105 107 109 112 116 119 123 126 130  Effluent NH4 (mg N/l)  Anoxic Aerobic Effluent NOx NOx NOx (mg N/l) (mg N/l) (mg N/l)  1 0 1 13 14 0 0 13 15 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 32 51 49 105 60 60 109 241 448 271 2 0 17 0 0 0  .  143 187 176 191 210 203 173 155 132 121 67 50 43 20 6 63 105 163 249 303 335 339 404 381 375 377 269 71  217 243 240 252 245 256 283 297 235 240 258 183 213 213 230 250 246 212 195 168 161 101 88 83 55 36 109 157 224 361 386 434 458 467 489 481 498 343 131  0 127 144 130 182 145 119  24 151 190 193 257 234 222  250 251 297 296 222 239 248 185 213 231 249 246 212 195 169 161 99 89 85 55 37 112 151 222 368 425 431 457 463 484 480 415 352 132 26 164 195 196 259 237 216 160  Anoxic N02 (mg N/l)  Aerobic N02 (mg N/l)  Effluent N02 (mg N/l)  0.0 0.0 35  40  1.2 0.5  2.3 1.9 0.3  2.4 1.8  4.0 0.7  4.0 1.1  4.5 0.7  1.9 0.5  0.6 0.6  0.2 0.1  0.4 0.3 0.2 0.3  0.3 0.3 0.2 0.2  0.1 0.1 0.1 0.1  0.2 0.6 0.1 0.2 0.3 0.5 1.0 2.5 0.6 0.3 0.2 0.6 0.1 0.1  0.3 0.3 0.4 0.1 1.3 11.3 23.3 30.2 18.5 15.6 13.9 20.4 8.0 9.5  0.1 0.1 0.2 0.0 1.4 12.8 24.7 31.9 20.2 16.8 15.2 21.6 8.1 9.4  0.0 0.2 0.1 0.1 0.0 0.5 0.4  8.2 0.7 1.1 0.7 0.2 1.7 2.4  8.8 0.8 0.3 22.6 0.9 1.4 1.8  MLE System #1  Date Nov 18/94 Nov 22/94 Nov 25/94 Nov 29/94 Dec 2/94 Dec 6/94 Dec 9/94 Dec 12/94 Dec 16/94 Dec 20/94 Dec 23/94 Dec 27/94 Dec 30/94 Jan 3/95 Jan 6/95 Jan 10/95 Jan 13/95 Jan 17/95 Jan 20/95 Jan 24/95 Jan 27/95 Jan 31/95 Feb 3/95 Feb 7/95 Feb 10/95 Feb 14/95 Feb 17/95 Feb 21/95 Feb 24/95 Feb 28/95 Mar 3/95 Mar 7/95  Day 133 137 140 144 147 151 154 157 161 165 168 172 175 179 182 186 189 193 196 200 203 207 210 214 217 221 224 228 231 235 238 242  Effluent NH4 (mg N/l) 1 21 13 16 18 18 13 10 7 9 9 3 7 17 25 36 109 63 17 15 29 58 60 60 53 70 29 7 25 17 31 21  Anoxic Aerobic Effluent NOx NOx NOx (mg N/l) (mg N/l) (mg N/l) 67 180 179 176 179 46 0 112 115 2 121 122 13 135 138 125 1 117 1 126 131 0 121 124 1 143 145 0 158 153 0 131 131 1 141 138 1 137 136 0 127 124 1 107 98 0 105 98 0 102 89 1 122 .116 137 310 293 55 231 214 1 156 149 0 149 137 160 2 150 1 185 142 0 144 138 5 181 164 1 137 130 0 180 166 153 332 309 0 94 89 1 106 100 1 108 102  161  Anoxic N02 (mg N/l) 3 1.3 0.0 1.3 11 0.3 0.2 0.0 0.6 0.0 0.0 0.7 0.1 0.0 0.2 0.0 0.0 0.6 74.0 31.0 0.3 0.0 0.9 0.7 0.0 2.8 0.2 0.0 84.0 0.0 0.2 0.3  Aerobic N02 (mg N/l) 10.0 38 43 54 91 68 68 69 87 83 84 85 80 82 70 68 62 78 171 129 89 85 95 115 87 106 78 87 171 73 62 61  Effluent N02 (mg N/l) 9.0 41 42 57 75 69 72 71 88 82 85 86 78 78 62 62 55 73 167 116 83 77 88 82 80 93 72 80 157 67 59 56  MLE System #1  Date Jul 12/94 Jul 14/94 Jul 15/94 Jul 18/94 Jul 20/94 Jul 22/94 Jul 25/94 Jul 27/94 Aug 1/94 Aug 3/94 Aug 5/94 Aug 8/94 Aug 10/94 Aug 12/94 Aug 15/94 Aug 17/94 Aug 19/94 Aug 22/94 Aug 24/94 Aug 26/94 Aug 29/94 Aug 31/94 Sep 2/94 Sep 6/94 Sep 9/94 Sep 12/94 Sep 14/94 Sep 16/94 Sep 19/94 Sep 21/94 Sep 23/94 Sep 26/94 Sep 28/94 Sep 30/94 Oct 3/94 Oct 7/94 Oct 11/94 Oct 14/94 Oct 17/94 Oct 19/94 Oct 21/94 Oct 23/94 Oct 25/94 Oct 28/94 Nov 1/94 Nov 4/94 Nov 8/94 Nov 11/94 Nov 15/94  Day 5 7 8 11 13 15 18 20 24 26 28 31 33 35 38 40 42 45 47 49 52 54 56 60 63 66 68 70 73 75 77 80 82 84 87 91 95 98 101 103 105 107 109 112 116 119 123 126 130  Anoxic 0-P04 (mg P/l)  Aerobic 0-P04 (mg P/l)  Anoxic TSS (mg/l)  Aerobic TSS (mg/l) 2232  Effluent TSS (mg/l)  Anoxic VSS (mg/l)  Aerobic VSS (mg/l) 1632  2408 2576 2528 2828 2724 2640 2712  45 43 36  1768 1848 1800 2008 1864 1784 1676  2584 2604  61 36  1576 1644  2.4 8.8 8.3 7.0 6.3 5.6 4.6 3.9 3.6 3.2 2.5 2.1 2.5 2.5 2.8 3.5 4.3 4.6 5.3 5.6 5.6 5.7 5.0 5.2 4.8 5.2 4.5 2.9  11.7 11.4 10.6 6.9 7.0 2.4 8.0 7.4 6.6 5.8 5.3 4.2 3.7 3.1 3.0 2.1 1.9 2.3 2.4 2.8 3.5 4.0 4.3 5.0 5.1 4.9 4.9 4.1 • .4.3 4.0 4.3 3.6 3.2  2944 3148 3376 3548 3336 3064 3236 3308 3248 3256 3884 3792 3836 3704 3620 3592 3584 3836 3784 3816 3896 3900 4228 4120 4032 3932 4316 4212  1980 2152 1920 1988 2108 2012 1980 2128 2252 2296 2640 2664 2632 2720 2612 2720 2716 2576 2604 2616 2724 2736 2824 2888 2852 2836 3108 3108  9 11 8 8 6 6 5 3 5 6 4 7 4 4 4 4 6 6 8 10 21 30 25 25 69 31 36 39  1980 2116 2244 2384 2212 2044 2184 2304 2240 2288 2796 2796 2908 2804 2720 2756 2780 2980 2984 3036 3092 3144 3328 3360 3300 3228 3596 3492  1340 1492 1304 1360 1424 1368 1364 1480 1576 1604 1932 1960 2000 2060 1968 2092 2116 2016 2044 2088 2172 2216 2284 2372 2352 2328 2572 2572  4.7 7.3 7.7 7.5 6.3 4.0 3.6  4.1 8.8 7.1 6.6 5.9 3.6 3.1  3960 3600 3720 4132 4704 5304 5696  3440 2848 2908 3356 3496 3908 4336  42 30 11 27 38 15 49  3212 2884 2940 3280 3768 4292 4696  2804 2300 2332 2648 2800 3148 3576  162  MLE System #1  Date Nov 18/94 Nov 22/94 Nov 25/94 Nov 29/94 Dec 2/94 Dec 6/94 Dec 9/94 Dec 12/94 Dec 16/94 Dec 20/94 Dec 23/94 Dec 27/94 Dec 30/94 Jan 3/95 Jan 6/95 Jan 10/95 Jan 13/95 Jan 17/95 Jan 20/95 Jan 24/95 Jan 27/95 Jan 31/95 Feb 3/95 Feb 7/95 Feb 10/95 Feb 14/95 Feb 17/95 Feb 21/95 Feb 24/95 Feb 28/95 Mar 3/95 Mar 7/95  Day 133 137 140 144 147 151 154 157 161 165 168 172 175 179 182 186 189 193 196 200 203 207 210 214 217 221 224 228 231 235 238 242  Anoxic 0-P04 (mg P/l) 2.8 2.5 2.3 2.3 2.2 2.4 2.9 3.3 3.0 2.9 3.6 3.1 3.0 3.6 5.3 5.6 4.9 4.0 3.5 3.2 3.6 4.2 3.9 4.6 4.6 4.1 4.4 4.2 5.5 4.3 3.9 4.1  Aerobic 0-P04 (mg P/l) 2.5 2.3 1.8 2.3 2.4 2.7 3.0 3.4 3.7 3.8 3.5 3.7 3.8 4.8 5.0 4.2 3.9 4.1 3.5 3.6 4.2 3.8 4.5 4.5 4.3 4.2 4.4 5.8 3.9 3.4 3.6  Anoxic TSS (mg/l) 5916 6404 7020 7218 7036 7068 6992 6704 6732 7036 7248 7224 6944 6500 6172 6264 6268 6880 6652 7016 7120 7248 7196 7520 7652 7304 7656 7188 7208 8244 8512 9356  163  Aerobic TSS (mg/l) 4408 4720 4936 5308 5348 5212 5348 5412 4932 4880 4796 5364 5060 5064 5004 4488 4588 5132 5356 5572 5328 5556 5436 5756 5664 5784 6016 6140 6088 6280 6500 6712  Effluent TSS (mg/l) 10 33 24 21 34 32 60 26 42 43 22 38 27 33 24 23 48 26 37 13 21 11 15 12 15 18 15 11 23 15 38 23  Anoxic VSS (mg/l) 4932 5396 6008 6128 6068 6164 6128 5876 5912 6220 6420 6376 6148 5772 5504 5616 5628 6156 5912 6224 6376 6504 6460 6728 6856 6504 6816 6412 6420 7336 7584 8304  Aerobic VSS (mg/l) 3644 3964 4204 4552 4592 4524 4668 4724 4320 4292 4248 4696 4452 4484 4436 4032 4132 4544 4720 4912 4768 4972 4884 5160 5076 5164 5352 5460 5412 5568 5764 5940  MLE System #1  Date Jul 12/94 Jul 14/94 Jul 15/94 Jul 18/94 Jul 20/94 Jul 22/94 Jul 25/94 Jul 27/94 Aug 1/94 Aug 3/94 Aug 5/94 Aug 8/94 Aug 10/94 Aug 12/94 Aug 15/94 Aug 17/94 Aug 19/94 Aug 22/94 Aug 24/94 Aug 26/94 Aug 29/94 Aug 31/94 Sep 2/94 Sep 6/94 Sep 9/94 Sep 12/94 Sep 14/94 Sep 16/94 Sep 19/94 Sep 21/94 Sep 23/94 Sep 26/94 Sep 28/94 Sep 30/94 Oct 3/94 Oct 7/94 Oct 11/94 Oct 14/94 Oct 17/94 Oct 19/94 Oct 21/94 Oct 23/94 Oct 25/94 Oct 28/94 Nov 1/94 Nov 4/94 Nov 8/94 Nov 11/94 Nov 15/94  Day 5 7 8 11 13 15 18 20 24 26 28 31 33 35 38 40 42 45 47 49 52 54 56 60 63 66 68 70 73 75 77 80 82 84 87 91 95 98 101 103 105 107 109 112 116 119 123 126 130  Effluent VSS (mg/l)  Anoxic BOD5 (mg/l)  Aerobic BOD5 (mg/l)  Effluent BOD5 (mg/l)  Anoxic COD (mg/l)  29 27 23  Aerobic COD (mg/l)  Effluent COD (mg/l)  403  390  390  417  35 24 8 8 7 7 5 5 4 3 4 5 3 5 4 4 4 4 6 6 6 9 17 22 22 19 50 26 30 33  9  11  5  39 24 9 23 32 15 44 164  5  302  302  368 401  351 417  384 335  446 446  429 429  412 429  420 438 412 429  403 386 394 394  403 386 394 394  333 333  317 267  300 350  318 366  318 318  334 318  477 438 473 456  445 438 420 438  445 438 438 419  510  510  510  579 377 356 309 326 341 341  516 417 316 267 275 288 320  526 397 377 303 309 306 320  MLE System #1  Date Nov 18/94 Nov 22/94 Nov 25/94 Nov 29/94 Dec 2/94 Dec 6/94 Dec 9/94 Dec 12/94 Dec 16/94 Dec 20/94 Dec 23/94 Dec 27/94 Dec 30/94 Jan 3/95 Jan 6/95 Jan 10/95 Jan 13/95 Jan 17/95 Jan 20/95 Jan 24/95 Jan 27/95 Jan 31/95 Feb 3/95 Feb 7/95 Feb 10/95 Feb 14/95 Feb 17/95 Feb 21/95 Feb 24/95 Feb 28/95 Mar 3/95 Mar 7/95  Day 133 137 140 144 147 151 154 157 161 165 168 172 175 179 182 186 189 193 196 200 203 207 210 214 217 221 224 228 231 235 238 242  Effluent VSS (mg/l) 8 30 21 18 28 30 56 23 36 37 19 29 23 30 22 23 41 17 16 12 16 8 15 11 13 15 13 9 21 14 32 19  Anoxic BOD5 (mg/l)  Aerobic BOD5 (mg/l)  Effluent BOD5 (mg/l)  29  16  15  36  17  14  9  14  10 114  11 12  74  9  7  94  10  9  35 14  12 10  12 11  11  11  7  86  14  14  165  11 8 19  x  Anoxic COD (mg/l)  Aerobic COD (mg/l)  Effluent COD (mg/l)  281 281 243 288 200 233  281 248 188 180 158 91  281 248 173 180 120 89  577 441 303 328  212 177 210 240  212 202 208 242  400 352 433 346  177 82 235 174  137 137 243 180  333 333  194 199  201 207  413 317 255  250 202 140 268 204 223  238 268 137 254 207 168  384 336  MLE System #1  Date Jul 12/94 Jul 14/94 Jul 15/94 Jul 18/94 Jul 20/94 Jul 22/94 Jul 25/94 Jul 27/94 Aug 1/94 Aug 3/94 Aug 5/94 Aug 8/94 Aug 10/94 Aug 12/94 Aug 15/94 Aug 17/94 Aug 19/94 Aug 22/94 Aug 24/94 Aug 26/94 Aug 29/94 Aug 31/94 Sep 2/94 Sep 6/94 Sep 9/94 Sep 12/94 Sep 14/94 Sep 16/94 Sep 19/94 Sep 21/94 Sep 23/94 Sep 26/94 Sep 28/94 Sep 30/94 Oct 3/94 Oct 7/94 Oct 11/94 Oct 14/94 Oct 17/94 Oct 19/94 Oct 21/94 Oct 23/94 Oct 25/94 Oct 28/94 Nov 1/94 Nov 4/94 Nov 8/94 Nov 11/94 Nov 15/94  Day 5 7 8 11 13 15 18 20 24 26 28 31 33 35 38 40 42 45 47 49 52 54 56 60 63 66 68 70 73 75 77 80 82 84 87 91 95 98 101 103 105 107 109 112 116 119 123 126 130  Anoxic VSS/TSS  Aerobic VSS/TSS 0.73  Effluent VSS/TSS  Aerobic Effluent Anoxic N02/NOx N02/NOX N02/NOX  0.73 0.72 0.71 0.71 0.68 0.68 0.62  0.64 0.63 0.64  0.61 0.63  0.57 0.67  0.67 0.67 0.66 0.67 0.66 0.67 0.67 0.70 0.69 0.70 0.72 0.74 0.76 0.76 0.75 0.77 0.78 0.78 0.79 0.80 0.79 0.81 0.79 0.82 0.82 0.82 0.83 0.83  0.68 0.69 0.68 0.68 0.68 0.68 0.69 0.70 0.70 0.70 0.73 0.74 0.76 0.76 0.75 0.77 0.78 0.78 0.78 0.80 0.80 0.81 0.81 0.82 0.82 0.82 0.83 0.83  0.89 0.73 0.88 0.88 0.83 0.83 0.80 1.00 0.80 0.83 0.75 0.71 1.00 1.00 1.00 1.00 1.00 1.00 0.75 0.90 0.81 0.73 0.88 0.76 0.72 0.84 0.83 0.85  0.01 0.00  0.01 0.01 0.00  0.01 0.01  0.02 0.00  0.02 0.00  0.02 0.00  0.01 0.00  0.00 0.00  0.00 0.00  0.00 0.00 0.00 0.01  0.00 0.00 0.00 0.00  0.00 0.00 0.00 0.00  0.03 0.01 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.00 0.00 0.00  0.01 0.00 0.00 0.00 0.00 0.03 0.05 0.07 0.04 0.03 0.03 0.04 0.02 0.07  0.00 0.00 0.00 0.00 0.00 0.03 0.06 0.07 0.04 0.03 0.03 0.05 0.02 0.07  0.81 0.80 0.79 0.79 0.80 0.81 0.82  0.82 0.81 0.80 0.79 0.80 0.81 0.82  0.93 0.80 0.82 0.85 0.84 1.00 0.90  0.00 0.00 0.00 0.00 0.00 0.00 0.00  0.34 0.00 0.01 0.00 0.00 0.01 0.01  0.34 0.00 0.00 0.12 0.00 0.01 0.01  166  0.15  M L E System #1  Day Date Nov 18/94 133 Nov 22/94 137 Nov 25/94 140 Nov 29/94 144 Dec 2/94 147 Dec 6/94 151 Dec 9/94 154 Dec 12/94 157 Dec 16/94 161 Dec 20/94 165 Dec 23/94 168 Dec 27/94 172 Dec 30/94 175 Jan 3/95 179 Jan 6/95 182 Jan 10/95 186 Jan 13/95 189 Jan 17/95 193 Jan 20/95 196 Jan 24/95 200 Jan 27/95 203 Jan 31/95 207 Feb 3/95 210 Feb 7/95 214 Feb 10/95 217 Feb 14/95 221 Feb 17/95 224 Feb 21/95 228 Feb 24/95 231 Feb 28/95 235 Mar 3/95 238 Mar 7/95 242  Anoxic VSS/TSS 0.83 0.84 0.86 0.85 0.86 0.87 0.88 0.88 0.88 0.88 0.89 0.88 0.89 0.89 0.89 0.90 0.90 0.89 0.89 0.89 0.90 0.90 0.90 0.89 0.90 0.89 0.89 0.89 0.89 0.89 0.89 0.89  Aerobic VSS/TSS 0.83 0.84 0.85 0.86 0.86 0.87 0.87 0.87 0.88 0.88 0.89 0.88 0.88 0.89 0.89 0.90 0.90 0.89 0.88 0.88 0.89 0.89 0.90 0.90 0.90 0.89 0.89 0.89 0.89 0.89 0.89 0.88  167  Effluent VSS/TSS 0.80 0.91 0.88 0.86 0.82 0.94 0.93 0.88 0.86 0.86 0.86 0.76 0.85 0.91 0.92 1.00 0.85 0.65 0.43 0.92 0.76 0.73 1.00 0.92 0.87 0.83 0.87 0.82 0.91 0.93 0.84 0.83  Aerobic Anoxic N02/NOx N02/NOx 0.04 0.06 0.22 0.03 0.00 0.38 0.65 0.45 0.67 0.85 0.58 0.30 0.20 0.54 0.00 0.57 0.61 0.60 0.53 0.00 0.00 0.64 0.60 0.70 0.58 0.10 0.00 0.65 0.65 0.20 0.00 0.65 0.00 0.61 0.64 0.60 0.54 0.55 0.56 0.56 0.30 0.57 0.00 0.57 0.59 0.45 0.62 0.70 0.60 0.00 0.56 0.59 0.57 0.20 0.48 0.00 0.52 0.55~ 0.78 0.00 0.20 0.58 0.56 0.30  Effluent N02/NOx 0.05 0.23 0.37 0.47 0.54 0.55 0.55 0.57 0.61 0.54 0.65 0.62 0.57 0.63 0.63 0.63 0.62 0.63 0.57 0.54 0.56 0.56 0.59 0.58 0.58 0.57 0.55 0.48 0.51 0.75 0.59 0.55  MLE System #1  Date Day Jul 12/94 5 Jul 14/94 7 Jul 15/94 8 Jul 18/94 11 Jul 20/94 13 Jul 22/94 15 Jul 25/94 18 Jul 27/94 20 Aug 1/94 24 Aug 3/94 26 Aug 5/94 28 Aug 8/94 31 Aug 10/94 33 Aug 12/94 35 Aug 15/94 38 40 Aug 17/94 Aug 19/94 42 Aug 22/94 45 Aug 24/94 47 Aug 26/94 49 Aug 29/94 52 Aug 31/94 54 Sep 2/94 56 Sep 6/94 60 Sep 9/94 63 Sep 12/94 66 Sep 14/94 68 Sep 16/94 70 Sep 19/94 73 Sep 21/94 75 Sep 23/94 77 Sep 26/94 80 82 Sep 28/94 Sep 30/94 84 Oct 3/94 87 Oct 7/94 91 Oct 11/94 95 Oct 14/94 98 Oct 17/94 101 Oct 19/94 103 Oct 21/94 105 Oct 23/94 107 Oct 25/94 109 Oct 28/94 112 Nov 1/94 116 Nov 4/94 119 Nov 8/94 123 Nov 11/94 126 Nov 15/94 130  Anoxic NH4 Removal Rate (mg N/d)  -358 -362 -371 -164 288 45 -160 -31 56 48 141 124 157 124 250 315 717 655 1252 1355 849 -762 -779 1333 1240 1630 2180 2335 1487 -1323 -132 285 818 1286 2289 2094  Aerobic NH4 Removal Rate (mg N/d)  2699 1374 3077 3083 3701 3397 3277 2919 2854 2790 2546 2482 2866 2304 2003 3517 4663 4581 6444 6823 8398 10677 9989 7109 7801 7308 6423 5110 4018 1136 2161 3873 5287 5380 6370 7297 168  %  %  %  Anoxic NH4 Removal  Aerobic NH4 Removal  System NH4 Removal  72.5 97.6 73.3 87.7 98.3 99.0 99.3 99.3 99.5 99.7 99.7 99.7 99.8 99.7 99.7 99.6 99.7 99.8 99.2 99.7 79.4 74.3 74.1 49.2 64.0 63.6 44.1 23.4 11.6 5.8 86.5 98.3 81.3 100.0 100.0 100.0  100 100 100 95 95 100 100 95 100 95 98 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 97 95 95 90 94 94 90 77 57 -5 99 100 98 100 100 100  -10.7 -34.7 -9.7 -4.9 7.1 1.3 -5.1 -1.1 1.9 1.7 5.2 4.7 5.2 5.1 11.0 8.2 13.3 12.5 16.2 16.5 7.4 -5.6 -6.1 8.4 9.2 12.4 13.0 9.7 4.1 -7.2 -5.6 6.7 11.2 19.3 26.4 22.3  Anoxic NOx Load (mg N/d)  11533 13420 13229 14498 15527 15056 12988 11936 10284 9859 6197 5391 5156 3318 2141 6575 9327 13318 21448 22939 25791 27212 27747 29052 29009 30038 20080 7666 1387 8836 11118 11119 14806 13482 12590  MLE System #1  Date Nov 18/94 Nov 22/94 Nov 25/94 Nov 29/94 Dec 2/94 Dec 6/94 Dec 9/94 Dec 12/94 Dec 16/94 Dec 20/94 Dec 23/94 Dec 27/94 Dec 30/94 Jan 3/95 Jan 6/95 Jan 10/95 Jan 13/95 Jan 17/95 Jan 20/95 Jan 24/95 Jan 27/95 Jan 31/95 Feb 3/95 Feb 7/95 Feb 10/95 Feb 14/95 Feb 17/95 Feb 21/95 Feb 24/95 Feb 28/95 Mar 3/95 Mar 7/95  Day 133 137 140 144 147 151 154 157 161 165 168 172 175 179 182 186 189 193 196 200 203 207 210 214 217 221 224 228 231 235 238 242  Anoxic NH4 Removal Rate (mg N/d) 2086 3385 3026 521 852 875 894 2277 2947 812 1320 1323 1466 1787 1673 2646 19 2019 2450 1927 1734 1525 1678 2356 1703 1783 940 -1294 815 125 500 516  Aerobic NH4 Removal Rate (mg N/d) 7629 7353 7622 10086 9963 9717 9605 8099 8134 10495 10210 9826 9379 9371 8619 8689 10135 8975 8997 9299 9262 9016 9086 8679 8591 8851 9529 11645 8999 9268 8672 8824  169  %  %  %  Anoxic NH4 Removal 21.3 28.0 26.4 4.4 7.1 7.3 7.8 20.5 25.2 6.8 10.8 11.6 12.9 14.3 13.7 18.7 0.1 12.5 19.1 15.7 13.1 10.0 10.7 15.0 11.7 11.2 7.4 -11.5 6.8 1.2 4.4 4.7  Aerobic NH4 Removal 99.1 84.6 90.5 89.6 89.0 87.6 90.4 91.8 93.0 93.9 93.8 97.0 94.7 87.4 81.5 75.7 54.9 63.4 86.9 89.8 80.2 66.0 64.7 64.9 66.9 62.5 80.7 92.8 80.4 86.7 80.0 84.9  System NH4 Removal 100 98 99 99 98 98 99 99 99 99 99 100 99 99 98 97 91 95 99 99 98 95 95 95 96 94 98 99 98 98 97 98  Anoxic NOx Load (mg N/d) 10216 9982 6356 7625 8386 7267 7826 7516 9397 10242 8492 9139 8879 8234 6940 6806 6612 7907 20091 14972 10252 9791 10517 12156 9463 11731 9004 11830 21814 6094 6871 7000  MLE System #1  Date Day 5 Jul 12/94 Jul 14/94 7 Jul 15/94 8 11 Jul 18/94 13 Jul 20/94 Jul 22/94 15 18 Jul 25/94 Jul 27/94 20 Aug 1/94 24 26 Aug 3/94 28 Aug 5/94 31 Aug 8/94 33 Aug 10/94 35 Aug 12/94 Aug 15/94 38 Aug 17/94 40 Aug 19/94 42 Aug 22/94 45 Aug 24/94 47 Aug 26/94 49 Aug 29/94 52 54 Aug 31/94 Sep 2/94 56 Sep 6/94 60 Sep 9/94 63 Sep 12/94 66 Sep 14/94 68 Sep 16/94 70 Sep 19/94 73 Sep 21/94 75 Sep 23/94 77 80 Sep 26/94 Sep 28/94 82 84 Sep 30/94 Oct 3/94 87 Oct 7/94 91 95 Oct 11/94 Oct 14/94 98 Oct 17/94 101 Oct 19/94 103 Oct 21/94 105 Oct 23/94 107 Oct 25/94 109 Oct 28/94 112 Nov 1/94 116 Nov 4/94 119 Nov 8/94 123 Nov 11/94 126 Nov 15/94 130  Anoxic Denitr Rate (mg N/d)  Anoxic Specific Denitr Rate (mg N/d/ mg VSS)  1103 884 485 512 317 538 582 820 817 1181 1445 1834 2068 1918 1725 2126 1998 1987 4064 1992 2641 3780 -173 2716 2742 3638 1756 2829  0.111 0.084 0.043 0.043 0.029 0.053 0.053 0.071 0.073 0.103 0.103 0.131 0.142 0.137 0.127 0.154 0.144 0.133 0.272 0.131 0.171 0.240 -0.010 0.162 0.166 0.225 0.098 0.162  1387 261 1334 2408 2567 3759 4696  0.086 0.018 0.091 0.147 0.136 0.175 0.200  Aerobic Nitr Rate (mg N/d)  Aerobic Specific Nitr Rate (mg N/d/ mg VSS)  9.6 6.6 3.7 3.5 2.0 3.6 4.5 6.9 7.9 .12.0 23.3 34.0 40.1 57.8 80.6 32.3 21.4 14.9 18.9 8.7 10.2 13.9 -0.6 9.3 9.5 12.1 8.7 36.9  2917 1743 2679 2856 2897 3075 2797 2869 2582 2869 2411 2703 2873 2451 2080 3249 3663 4305 8036 5976 7106 8546 4648 7839 7765 8853 5182 4088  0.218 0.117 0.205 0.210 0.203 0.225 0.205 0.194 0.164 0.179 0.125 0.138 0.144 0.119 0.106 0.155 0.173 0.214 0.393 0.286 0.327 0.386 0.203 0.330 0.330 0.380 0.201 0.159  78.4 123.8 63.8 81.3 76.9 89.6 84.8 97.6 90.0 102.6 94.4 108.6 100.0 106.1 103.4 92.0 78.3 93.8 123.8 87.3 67.2 59.4 34.5 54.3 63.7 77.1 35.5 18.8  0.17 0.09 0.09 0.18 0.15 0.22 0.46 0.48 0.75 1.00 1.90 2.44 2.51 4.08 6.40 2.11 1.41 0.99 0.67 0.59 0.54 0.50 0.50 0.48 0.57 0.53 0.94 2.97  100.0 3.0 12.0 21.7 17.3 27.9 37.3  1604 1620 3166 4295 5157 6090 6973  0.057 0.070 0.136 0.162 0.184 0.193 0.195  8.2 64.9 80.3 66.1 95.9 95.6 95.6  8.32 0.64 0.86 1.07 1.21 1.96 2.41  %  Anoxic Denitr  170  %  Aerobic Nitr  Anoxic COD:NOx Entering (mg COD/ mg N)  MLE System #1  Date Nov 18/94 Nov 22/94 Nov 25/94 Nov 29/94 Dec 2/94 Dec 6/94 Dec 9/94 Dec 12/94 Dec 16/94 Dec 20/94 Dec 23/94 Dec 27/94 Dec 30/94 Jan 3/95 Jan 6/95 Jan 10/95 Jan 13/95 Jan 17/95 Jan 20/95 Jan 24/95 Jan 27/95 Jan 31/95 Feb 3/95 Feb 7/95 Feb 10/95 Feb 14/95 Feb 17/95 Feb 21/95 Feb 24/95 Feb 28/95 Mar 3/95 Mar 7/95  Day 133 137 140 144 147 151 154 157 161 165 168 172 175 179 182 186 189 193 196 200 203 207 210 214 217 221 224 228 231 235 238 242  Anoxic Denitr Rate (mg N/d) 5771 6929 6356 7480 7453 7196 7755 7516 9322 10242 8492 9064 8805 8234 6866 6806 6612 7833 9887 10875 10176 9791 10366 12081 9463 11361 8928 11830 10314 6094 6797 6926  Anoxic Specific Denitr Rate (mg N/d/ mg VSS) 0.234 0.257 0.212 0.244 0.246 0.233 0.253 0.256 0.315 0.329 0.265 0.284 0.286 0.285 0.249 0.242 0.235 0.254 0.334 0.349 0.319 0.301 0.321 0.359 0.276 0.349 0.262 0.369 0.321 0.166 0.179 0.167  %  Anoxic Denitr 56.5 69.4 100.0 98.1 88.9 99.0 99.1 100.0 99.2 100.0 100.0 99.2 99.2 100.0 98.9 100.0 100.0 99.1 49.2 72.6 99.3 100.0 98.6 99.4 100.0 96.8 99.2 100.0 47.3 100.0 98.9 98.9  171  Aerobic Nitr Rate (mg N/d) 7608 8748 7503 8723 8842 8380 9057 8777 10797 11874 9862 10524 10224 9547 7973 7895 7654 9080 13145 13291 11811 11342 12031 13959 10912 13184 10306 13643 13682 7055 7859 8012  Aerobic Specific Nitr Rate (mg N/d/ mg VSS) 0.209 0.221 0.178 0.192 0.193 0.185 0.194 0.186 0.250 0.277 0.232 0.224 0.230 0.213 0.180 0.196 0.185 0.200 0.278 0.271 0.248 0.228 0.246 0.271 0.215 0.255 0.193 0.250 0.253 0.127 0.136 0,135  %  Aerobic Nitr 98.9 100.6 89.1 77.5 79.0 75.6 85.3 99.5 123.5 106.3 90.6 103.9 103.2 89.0 75.4 68.8 41.5 64.2 127.0 128.4 102.3 83.0 85.7 104.3 85.0 93.1 87.3 108.7 122.2 66.0 72.5 77.1  Anoxic COD:NOx Entering (mg COD/ mg N) 3.48 3.31 6.10 4.78 4.51 4.56 4.23 4.24 3.47 3.47 3.97 3.57 3.80 4.00 4.44 4.47 5.10 4.26 1.49 2.13 3.25 3.33 2.86 2.53 3.22 2.41 3.20 2.26 1.21 5.91 4.75 4.51  MLE System #1  Date Jul 12/94 Jul 14/94 Jul 15/94 Jul 18/94 Jul 20/94 Jul 22/94 Jul 25/94 Jul 27/94 Aug 1/94 Aug 3/94 Aug 5/94 Aug 8/94 Aug 10/94 Aug 12/94 Aug 15/94 Aug 17/94 Aug 19/94 Aug 22/94 Aug 24/94 Aug 26/94 Aug 29/94 Aug 31/94 Sep 2/94 Sep 6/94 Sep 9/94 Sep 12/94 Sep 14/94 Sep 16/94 Sep 19/94 Sep 21/94 Sep 23/94 Sep 26/94 Sep 28/94 Sep 30/94 Oct 3/94 Oct 7/94 Oct 11/94 Oct 14/94 Oct 17/94 Oct 19/94 Oct 21/94 Oct 23/94 Oct 25/94 Oct 28/94 Nov 1/94 Nov 4/94 Nov 8/94 Nov 11/94 Nov 15/94  Day 5 7 8 11 13 15 18 20 24 26 28 31 33 35 38 40 42 45 47 49 52 54 56 60 63 66 68 70 73 75 77 80 82 84 87 91 95 98 101 103 105 107 109 112 116 119 123 126 130  Anoxic Aerobic Aerobic COD:NOx Alk:NH4 Alk:NH4 Aerobic Removed Added Nitrified (mg COD/ (g CaC03/ (g CaC03/ SRT (days) mg N) gN) gN)  System SRT (days)  20 20 20 20 20 20 20 20 20 20 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13  43.0 42.5 41.8 43.3 43.7 42.0 41.5 43.2 42.1 42.9 28.4 28.4 28.0 27.6 28.7 28.5 28.0 26.6 25.9 26.2 26.5 22.6 25.3 25.4 24.9  9.8 9.9 9.8 9.8 9.8 9.8 9.8 9.8 9.9 9.9 9.9 9.8 3.9 10.2 10.1 10.2 10.2 10.4 10.4 10.4 10.4 9.6 9.8 9.6 9.6 9.8 10.0 10.1 9.8 10.1 9.4 9.4 9.4 9.4 9.4 9.4 9.4 9.3 9.3  13 13 13 13 13 13 13  23.6 25.2 27.1 25.4 25.1 27.4 24.6  9.1 8.9 9.1 9.1 9.3 9.1 9.3  10 10 10 10 1.82 1.35 2.41 5.01 7.20 6.04 10.28 6.99 9.49 8.32 8.17 7.17 6.27 7.05 7.95 6.54 6.58 6.62 3.51 6.79 5.26 3.63 -80.41 5.18 6.00 4.41 10.76 8.06 8.32 21.53 7.17 4.95 7.00 7.03 6.47  5.70 6.46 6.39 5.93 5.25 5.18 5.22 5.99 5.63 5.81 3.93  5.58 4.96 5.23 4.44 4.42  8.37 7.85 6.12 8.12 7.07 6.34 10.92 7.29 7.02 6.27 7.43  7.34 7.25 6.76 6.32 5.96 172  Simulated Leachate Flow (l/d)  MLE System #1  Date Nov 18/94 Nov 22/94 Nov 25/94 Nov 29/94 Dec 2/94 Dec 6/94 Dec 9/94 Dec 12/94 Dec 16/94 Dec 20/94 Dec 23/94 Dec 27/94 Dec 30/94 Jan 3/95 Jan 6/95 Jan 10/95 Jan 13/95 Jan 17/95 Jan 20/95 Jan 24/95 Jan 27/95 Jan 31/95 Feb 3/95 Feb 7/95 Feb 10/95 Feb 14/95 Feb 17/95 Feb 21/95 Feb 24/95 Feb 28/95 Mar 3/95 Mar 7/95  Day 133 137 140 144 147 151 154 157 161 165 168 172 175 179 182 186 189 193 196 200 203 207 210 214 217 221 224 228 231 235 238 242  Anoxic Aerobic Aerobic COD:NOx Alk:NH4 Alk:NH4 Nitrified Aerobic Removed Added SRT (mg COD/ (g CaC03/ (g CaC03/ (days) mg N) 9N) gN) 6.16 4.19 5.36 13 13 4.77 4.08 5.11 13 6.10 4.00 5.74 10 4.88 4.17 5.15 5.08 4.07 5.06 10 4.04 5.20 10 4.60 4.27 4.15 4.87 10 4.24 4.79 5.72 10 10 3.50 3.98 4.12 3.47 3.93 3.77 10 3.97 4.02 4.73 10 3.60 3.95 4.20 10 3.83 4.03 4.30 10 4.00 3.55 4.21 10 3.99 5.29 10 4.48 4.47 4.01 5.95 10 3.68 5.42 15 5.10 4.28 15 4.30 3.32 3.04 4.49 3.98 15 2.93 4.27 3.65 15 3.28 4.01 3.84 20 3.33 4.07 4.01 20 2.90 4.07 3.87 20 2.55 3.69 3.08 20 4.14 3.22 4.12 20 2.48 4.11 3.53 20 3.23 3.88 4.06 20 2.26 4.06 3.11 20 2.55 4.53 3.35 20 5.91 5.15 6.99 20 4.80 4.13 4.97 20 4.56 4.48 5.34 20  173  System SRT (days) 28.2 26.3 27.6 20.9 20.3 20.4 19.2 20.2 20.1 20.4 21.5 20.5 20.8 20.0 20.2 20.7 28.3 30.7 30.1 30.7 40.5 41.7 40.6 41.3 41.4 40.2 40.7 40.4 38.8 41.1 38.8 41.3  Simulated Leachate Flow (l/d) 9.3 9.3 9.3 9.3 9.3 9.1 9.3 9.3 9.3 9.3 9.4 9.3 9.3 9.3 9.3 9.3 9.3 9.3 9.3 9.3 9.4 9.4 9.4 9.1 9.0 9.0 9.1 9.1 9.1 9.1 9.1 9.1  MLE System #1  Date Jul 12/94 Jul 14/94 Jul 15/94 Jul 18/94 Jul 20/94 Jul 22/94 Jul 25/94 Jul 27/94 Aug 1/94 Aug 3/94 Aug 5/94 Aug 8/94 Aug 10/94 Aug 12/94 Aug 15/94 Aug 17/94 Aug 19/94 Aug 22/94 Aug 24/94 Aug 26/94 Aug 29/94 Aug 31/94 Sep 2/94 Sep 6/94 Sep 9/94 Sep 12/94 Sep 14/94 Sep 16/94 Sep 19/94 Sep 21/94 Sep 23/94 Sep 26/94 Sep 28/94 Sep 30/94 Oct 3/94 Oct 7/94 Oct 11/94 Oct 14/94 Oct 17/94 Oct 19/94 Oct 21/94 Oct 23/94 Oct 25/94 Oct 28/94 Nov 1/94 Nov 4/94 Nov 8/94 Nov 11/94 Nov 15/94  Day 5 7 8 11 13 15 18 20 24 26 28 31 33 35 38 40 42 45 47 49 52 54 56 60 63 66 68 70 73 75 77 80 82 84 87 91 95 98 101 103 105 107 109 112 116 119 123 126 130  Clarifier Recycle Flow (l/d)  Clarifier Recycle Ratio  Chemical Flow  Total Flow  Effluent NOx  (l/d)  (l/d)  (mg/l)  59.4 59.4 59.4 59.4 60.3 60.3 61.2 63.0 63.9 63.0 63.0 63.0 63.0 62.1 63.0 62.1 61.2 61.2 61.2 61.2 61.2 61.2 61.2 62.1 60.3 59.4 60.3 59.4 59.4 59.4 59.4 59.4 59.4 59.4 59.4 60.3 60.3 58.5 58.5  6.1 6.0 6.1 6.1 6.2 6.2 6.2 6.4 6.5 6.4 6.4 6.4 16.2 6.1 6.2 6.1 6.0 5.9 5.9 5.9 5.9 6.4 6.2 6.5 6.3 6.1 6.0 5.9 6.1 5.9 6.3 6.3 6.3 6.3 6.3 6.4 6.4 6.3 6.3  0.27 0.28 0.27 0.28 0.27 0.27 0.28 0.28 0.28 0.14 0.12 0.25 0.24 0.21 0.23 0.23 0.21 0.28 0.28 0.28 0.29 0.29 0.29 0.29 0.30 0.30 0.30 0.50 0.59 0.91 0.92 0.90 0.99 0.91 1.07 1.02 1.06 0.71 0.31  10.1 10.2 10.1 10.1 10.1 10.1 10.1 10.1 10.2 10.0 10.0 10.0 4.1 10.4 10.3 10.4 10.4 10.7 10.7 10.7 10.7 9.9 10.1 9.9 9.9 10.1 10.3 10.6 10.4 11.0 10.3 10.3 10.4 10.3 10.5 10.4 10.5 10.0 9.6  57.6 58.5 58.5 57.6 57.6 57.6 56.7  6.3 6.6 6.4 6.3 6.2 6.3 6.1  0.31 0.31 0.52 0.67 0.74 0.85 0.95  9.4 9.2 9.6 9.8 10.1 10.0 10.3  174  Effluent Dilution Factor  213 231 249 246 212 195 169 161 99 89 85 55 37 112 151 222 368 425 431 457 463 484 480 415 352 132  1.03 1.03 1.03 1.03 1.03 1.03 1.03 1.03 1.03 1.01 1.01 1.03 1.06 1.02 1.02 1.02 1.02 1.03 1.03 1.03 1.03 1.03 1.03 1.03 1.03 1.03 1.03 1.05 1.06 1.09 1.10 1.10 1.11 1.10 1.11 1.11 1.11 1.08 1.03  26 164 195 196 259 237 216  1.03 1.03 1.06 1.07 1.08 1.09 1.10  250 251 297 296' 222 239 248 185  Effluent NH4 (mg N/l)  MLE System #1  Date Nov 18/94 Nov 22/94 Nov 25/94 Nov 29/94 Dec 2/94 Dec 6/94 Dec 9/94 Dec 12/94 Dec 16/94 Dec 20/94 Dec 23/94 Dec 27/94 Dec 30/94 Jan 3/95 Jan 6/95 Jan 10/95 Jan 13/95 Jan 17/95 Jan 20/95 Jan 24/95 Jan 27/95 Jan 31/95 Feb 3/95 Feb 7/95 Feb 10/95 Feb 14/95 Feb 17/95 Feb 21/95 Feb 24/95 Feb 28/95 Mar 3/95 Mar 7/95  Day 133 137 140 144 147 151 154 157 161 165 168 172 175 179 182 186 189 193 196 200 203 207 210 214 217 221 224 228 231 235 238 242  Clarifier Recycle Flow (l/d) 56.7 56.7 56.7 63.0 62.1 62.1 62.1 62.1 65.7 64.8 64.8 64.8 64.8 64.8 64.8 64.8 64.8 64.8 64.8 64.8 65.7 65.7 65.7 65.7 65.7 64.8 65.7 65.7 65.7 64.8 64.8 64.8  Clarifier Recycle Ratio 6.1 6.1 6.1 6.8 6.7 6.8 6.7 6.7 7.0 7.0 6.9 7.0 7.0 6.9 7.0 6.9 7.0 6.9 6.9 6.9 7.0 7.0 7.0 7.2 7.3 7.2 7.2 7.2 7.2 7.1 7.1 7.1  Chemical Flow (l/d) 0.94 1.00 0.96 0.96 0.98 1.01 1.02 1.11 1.00 1.02 1.05 1.04 1.06 1.03 1.09 1.03 0.93 0.91 1.16 1.13 1.06 1.00 1.01 1.02 1.06 1.06 0.92 0.93 0.99 1.11 0.89 0.93  175  Total Flow (l/d) 10.3 10.3 10.3 10.3 10.3 10.1 10.3 10.4 10.3 10.3 10.5 10.4 10.4 10.4 10.4 10.4 10.2 10.2 10.5 10.5 10.5 10.4 10.4 10.1 10.1 10.1 10.0 10.1 10.1 10.2 10.0 10.0  Effluent NOx (mg/l) 179 179 115 122 138 125 131 124 145 153 131 138 136 124 98 98 89 116 293 214 149 137 150 142 138 164 130 166 309 89 100 102  Effluent Dilution Factor 1.10 1.11 1.10 1.10 1.11 1.11 1.11 1.12 1.11 1.11 1.11 1.11 1.11 1.11 1.12 1.11 1.10 1.10 1.12 1.12 1.11 1.11 1.11 1.11 1.12 1.12 1.10 1.10 1.11 1.12 1.10 1.10  Corrected Effluent NH4 (mg N/l) 14 18 20 20 14 11 8 10 10 3 8 19 28 40 120 69 19 17 32 64 66 67 59 78 32 8 28 19 34 23  MLE System #1  Date Jul 12/94 Jul 14/94 Jul 15/94 Jul 18/94 Jul 20/94 Jul 22/94 Jul 25/94 Jul 27/94 Aug 1/94 Aug 3/94 Aug 5/94 Aug 8/94 Aug 10/94 Aug 12/94 Aug 15/94 Aug 17/94 Aug 19/94 Aug 22/94 Aug 24/94 Aug 26/94 Aug 29/94 Aug 31/94 Sep 2/94 Sep 6/94 Sep 9/94 Sep 12/94 Sep 14/94 Sep 16/94 Sep 19/94 Sep 21/94 Sep 23/94 Sep 26/94 Sep 28/94 Sep 30/94 Oct 3/94 Oct 7/94 Oct 11/94 Oct 14/94 Oct 17/94 Oct 19/94 Oct 21/94 Oct 23/94 Oct 25/94 Oct 28/94 Nov 1/94 Nov 4/94 Nov 8/94 Nov 11/94 Nov 15/94  Total Total Corrected Effluent Inorganic Effluent Inorganic Nitrogen NOx Nitrogen Removal (mg N/l) (%) Day (mg N/l) 5 7 8 11 13 15 18 257 20 258 24 306 304 26 228 28 31 242 33 251 35 190 38 40 217 42 236 45 255 47 251 49 218 200 52 54 174 165 56 60 102 92 63 66 88 57 68 70 38 73 115 75 158 77 235 80 401 467 82 84 473 87 505 91 508 95 539 98 532 101 462 103 379 105 136 107 27 109 170 112 116 206 119 211 123 280 126 259 130 238  176  MLE System #1  Date Nov 18/94 Nov 22/94 Nov 25/94 Nov 29/94 Dec 2/94 Dec 6/94 Dec 9/94 Dec 12/94 Dec 16/94 Dec 20/94 Dec 23/94 Dec 27/94 Dec 30/94 Jan 3/95 Jan 6/95 Jan 10/95 Jan 13/95 Jan 17/95 Jan 20/95 Jan 24/95 Jan 27/95 Jan 31/95 Feb 3/95 Feb 7/95 Feb 10/95 Feb 14/95 Feb 17/95 Feb 21/95 Feb 24/95 Feb 28/95 Mar 3/95 Mar 7/95  Day 133 137 140 144 147 151 154 157 161 165 168 172 175 179 182 186 189 193 196 200 203 207 210 214 217 221 224 228 231 235 238 242  Total Total Inorganic Corrected Effluent Effluent Inorganic Nitrogen NOx Nitrogen Removal (mg N/l) (mg N/l) (%) 197 198 141 88 127 152 87 135 85 153 172 159 87 139 145 160 86 150 87 139 161 168 86 85 170 180 87 146 156 157 87 153 151 159 86 157 87 138 137 88 110 149 88 109 98 218 82 196 84 127 348 72 329 257 79 240 198 83 166 216 82 152 233 81 166 82 158 225 154 213 82 79 183 261 85 143 175 183 191 83 370 67 343 100 119 89 110 144 86 112 135 87  177  MLE System #2  Date Day Jul 12/94 5 Jul 14/94 7 Jul 15/94 8 Jul 18/94 11 Jul 20/94 13 Jul 22/94 15 Jul 25/94 18 Jul 27/94 20 Aug 1/94 24 Aug 3/94 26 Aug 5/94 28 Aug 8/94 31 Aug 10/94 33 Aug 12/94 35 Aug 15/94 38 Aug 17/94 40 Aug 19/94 42 Aug 22/94 45 Aug 24/94 47 Aug 26/94 49 Aug 29/94 52 Aug 31/94 54 Sep 2/94 56 Sep 6/94 60 Sep 9/94 63 Sep 12/94 66 Sep 14/94 68 Sep 16/94 70 Sep 19/94 73 Sep 21/94 75 Sep 23/94 77 Sep 26/94 80 Sep 28/94 82 Sep 30/94 84 Oct 3/94 87 Oct 7/94 91 Oct 11/94 95 Oct 14/94 98 Oct 17/94 101 Oct 19/94 103 Oct 21/94 105 Oct 23/94 107 Oct 25/94 109 Oct 28/94 112 Nov 1/94 116 Nov 4/94 119 Nov 8/94 123 Nov 11/94 126  P04 Feed Flow (ml/hr) 11.3 11.4 11.4 11.7 11.4 11.6 11.4 11.4 11.7 11.5 11.5 5.8 5.2 5.6 5.7 4.6 5.2 5.4 5.0 4.6 4.9 4.8 5.0 5.1 5.1 5.1 5.0 5.2 4.9 4.8 5.2 5.2 5.5 4.8 4.7 4.4 4.7 5.5 4.9 4.7 4:9 4.9 4.9 4.9 5.1 4.8 4.9 5.2  CH30H Feed Flow (ml/hr) 0 0 0 0 0 0 0 0 0 0 0 0 0 6.2 5.4 5.8 5.65.4 4.9 9.1 8.8 8.8 8.9 8.9 9.1 9.0 9.2 9.2 9.5 8.9 9.1 9.3 9.2 9.4 9.0 9.1 9.2 9.5 9.2 9.f 9.4 9.4 9.4 9.4 9.3 9.2 9.4 9.9  NH4CI Feed Flow (ml/hr) 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 8.9 8.5 8.5 8.8 8.8 9.0 8.8 8.8 9.1 9.5 9.3 9.5 9:6 9.6 0.0 0.0 9.6 8.7 9.9 9.8 178  NaHC03 Feed Flow (ml/hr) 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 10.7 13.0 29.2 30.3 33.0 35.0 23.6 15.9 27.3 25.2 1.3 0.0 0.0 0.0 0.0 9.2 20.0 19.7 21.4  Leachate (l/d)  Clarifier Recycle (l/d)  10.1 9.9 10.4 10.4 5.5 9.9 9.8 10.1 10.0 9.8 9.9 9.9 10.2 10.1 9.9 9.6 9.5 9.8 9.6 9.5 9.5 9.5 9.6 9.5 10.1 9.8 9.6 9.8 9.6 9.6 9.4 9.5 9.1 9.4 9.4 9.2 9.5 9.5 9.5 9.5 9.5 9.6 9.9 9.8 9.4 9.2  60.3 60.3 60.3 60.3 59.4 59.4 59.4 59.4 59.4 63.9 63.0 61.2 62.1 63.0 62.1 62.1 63.0 62.1 62.1 62.1 62.1 62.1 62.1 62.1 62.1 62.1 62.1 62.1 62.1 59.4 58.5 58.5 57.6 60.3 59.4 58.5 59.4 60.3 56.7 56.7 56.7 56.7 56.7 57.6 58.5 57.6  Anoxic Overflow (l/d)  73.0 71.2 72.4 73.2 72.1 71.8 72.6 72.0 71.8 71.7 71.7 71.7 71.8 71.7 72.3 72.0 72.2 72.4 72.2 69.5 68.5 68.5 67.2 70.2 69.3 68.3 69.5 70.4 66.8 66.8 66.3 66.4 67.2 67.9 68.5 67.4  MLE System #2  Date Nov 15/94 Nov 18/94 Nov 22/94 Nov 25/94 Nov 29/94 Dec 2/94 Dec 6/94 Dec 9/94 Dec 12/94 Dec 16/94 Dec 20/94 Dec 23/94 Dec 27/94 Dec 30/94 Jan 3/95 Jan 6/95 Jan 10/95 Jan 13/95 Jan 17/95 Jan 20/95 Jan 24/95 Jan 27/95 Jan 31/95 Feb 3/95 Feb 7/95 Feb 10/95 Feb 14/95 Feb 17/95 Feb 21/95 Feb 24/95 Feb 28/95 Mar 3/95 Mar 7/95  Day 130 133 137 140 144 147 151 154 157 161 165 168 172 175 179 182 186 189 193 196 200 203 207 210 214 217 221 224 228 231 235 238 242  P04 Feed Flow (ml/hr) 4.9 4.9 5.2 4.7 5.0 5.5 4.8 5.0 4.9 5.0 5.6 4.9 5.0 5.7 4.8 5.7 4.9 5.0 5.6 5.3 5.5 5.2 5.4 5.1 5.1 5.0 5.5 5.0 5.3 5.0 5.1 5.1 5  CH30H Feed Flow (ml/hr) 9.6 10.0 9.6 9.8 9.8 9.8 9.7 9.7 9.4 10.4 10.7 10.9 10.4 10.4 10.5 10.5 10.1 10.6 10.6 10.5 10.7 10.8 10.6 10.6 10.7 10.6 10.7 8.1 7.8 7.7 7.9 7.9 8.2  NH4CI Feed Flow (ml/hr) 9.8 10.3 10.4 10.3 10.1 10.1 10.1 10.3 10.3 10.4 10.7 10.8 10.8 10.4 10.8 10.2 10.9 10.5 11.0 11.0 10.8 10.8 10.6 10.8 10.9 10.9 10.7 10.8 11.0 10.8 10.8 10.8 11.3  179  NaHC03 Feed Flow (ml/hr) 25.9 29.3 28.4 30.0 31.5 31.7 33.4 33.5 36.1 28.8 31.8 34.5 26.1 34.8 22.8 28.3 27.7 20.5 24.2 35.7 33.3 31.5 26.1 31.3 33.5 30.6 37.7 29.1 30.7 31.9 0 24.1 25.8  Leachate (l/d) 9.6 9.6 9.4 9.4 9.4 8.9 9.1 8.9 9.1 9.1 9.1 9.2 9.1 9.2 9.4 9.2 9.5 8.9 8.9 8.8 9.2 8.8 9.2 9.8 8.1 8.9 9.1 8.9 9.1 8.4 9.4 9.1 9.2  Clarifier Recycle (l/d) 57.6 58.5 58.5 57.6 58.5 58.5 58.5 58.5 58.5 73.8 73.8 76.5 75.6 74.7 74.7 74.7 73.8 73.8 73.8 73.8 73.8 73.8 73.8 72.9 72.9 72.9 75.6 74.7 73.8 73.8 73.8 73.8 73.8  Anoxic Overflow (l/d) 67.8 68.7 68.5 67.6 68.5 68.0 68.2 68.0 68.2 83.5 83.5 86.3 85.3 84.5 84.7 84.5 83.9 83.3 83.4 83.3 83.7 83.2 83.6 83.3 81.6 82.4 85.3 84.2 83.6 82.8 83.8 83.5 83.7  MLE System #2  Date Day Jul 12/94 5 Jul 14/94 7 Jul 15/94 8 Jul 18/94 11 Jul 20/94 13 Jul 22/94 15 Jul 25/94 18 Jul 27/94 20 Aug 1/94 24 Aug 3/94 26 Aug 5/94 28 Aug 8/94 31 Aug 10/94 33 Aug 12/94 35 Aug 15/94 38 Aug 17/94 40 Aug 19/94 42 Aug 22/94 45 Aug 24/94 47 Aug 26/94 49 Aug 29/94 52 Aug 31/94 54 Sep 2/94 56 Sep 6/94 60 Sep 9/94 63 Sep 12/94 66 Sep 14/94 68 Sep 16/94 70 Sep 19/94 73 Sep 21/94 75 Sep 23/94 77 Sep 26/94 80 Sep 28/94 82 Sep 30/94 84 Oct 3/94 87 Oct 7/94 91 Oct 11/94 95 Oct 14/94 98 Oct 17/94 101 Oct 19/94 103 Oct 21/94 105 Oct 23/94 107 Oct 25/94 109 Oct 28/94 112 Nov 1/94 116 Nov 4/94 119 Nov 8/94 123 Nov 11/94 126  Aerobic Overflow (l/d) 70.7 70.5 71.0 71.0 65.2 69.6 69.5 69.8 69.7 73.8 73.0 71.2 72.4 73.2 72.1 71.8 72.6 72.0 71.8 71.7 71.7 71.7 71.8 71.7 72.3 72.0 72.2 72.7 72.5 70.2 69.2 69.3 68.1 70.8 69.7 68.9 70.1 70.4 66.8 66.8 66.3 66.4 67.4 68.4 69.0 67.9  Aerobic Wasting (l/d) 0 0 0 0 0 0 0 0 1 1 1 1 1 0 0 0 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75 0.75  Anoxic AHRT (hr)  180  Aerobic AHRT (hr)  Clarifier AHRT (hr)  1.64 1.68 1.66 1.64 1.66 1.67 1.65 1.67 1.67 1.67 1.67 1.67 1.67 1.67 1.66 1.67 1.66 1.66 1.66 1.73 1.75 1.75 1.78 1.71 1.73 1.76 1.73 1.71 1.80  3.40 3.41 3.38 3.38 3.68 3.45 3.45 3.44 3.44 3.25 3.29 3.37 3.31 3.28 3.33 3.34 3.30 3.33 3.34 3.35 3.35 3.35 3.34 3.35 3.32 3.33 3.32 3.30 3.31 3.42 3.47 3.46 3.53 3.39 3.44 3.48 3.43 3.41 3.59  1.36 1.36 1.35 1.35 1.47 1.38 1.38 1.38 1.38 1.30 1.31 1.35 1.33 1.31 1.33 1.34 1.32 1.33 1.34 1.34 1.34 1.34 1.34 1.34 1.33 1.33 1.33 1.32 1.32 1.37 1.39 1.38 1.41 1.36 1.38 1.39 1.37 1.36 1.44  1.81 1.81 1.79 1.77 1.75 1.78  3.62 3.61 3.56 3.51 3.48 3.53  1.45 1.45 1.42 1.40 1.39 1.41  MLE System #2  Date Nov 15/94 Nov 18/94 Nov 22/94 Nov 25/94 Nov 29/94 Dec 2/94 Dec 6/94 Dec 9/94 Dec 12/94 Dec 16/94 Dec 20/94 Dec 23/94 Dec 27/94 Dec 30/94 Jan 3/95 Jan 6/95 Jan 10/95 Jan 13/95 Jan 17/95 Jan 20/95 Jan 24/95 Jan 27/95 Jan 31/95 Feb 3/95 Feb 7/95 Feb 10/95 Feb 14/95 Feb 17/95 Feb 21/95 Feb 24/95 Feb 28/95 Mar 3/95 Mar 7/95  Day 130 133 137 140 144 147 151 154 157 161 165 168 172 175 179 182 186 189 193 196 200 203 207 210 214 217 221 224 228 231 235 238 242  Aerobic Overflow (l/d) 68.4 69.4 69.2 68.3 69.3 68.8 69.0 68.8 69.1 84.2 84.3 87.2 86.0 85.4 85.3 85.2 84.6 83.8 83.9 84.1 84.4 84.0 84.3 84.1 82.4 83.2 86.3 84.9 84.3 83.6 83.8 84.1 84.3  Anoxic AHRT (hr) 1.77 1.75 1.75 1.77 1.75 1.76 1.76 1.76 1.76 1.44 1.44 1.39 1.41 1.42 1.42 1.42 1.43 1.44 1.44 1.44 1.43 1.44 1.43 1.44 1.47 1.46 1.41 1.42 1.44 1.45 1.43 1.44 1.43  Aerobic Wasting (l/d) 0.75 0.75 0.75 0.75 1 1 1 1 1 1 1 1 1 1 1 1 1 0.67 0.67 0.67 0.67 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5  181  Aerobic AHRT (hr) 3.51 3.46 3.47 3.51 3.47 3.49 3.48 3.49 3.47 2.85 2.85 2.75 2.79 2.81 2.81 2.82 2.84 2.86 2.86 2.85 2.84 2.86 2.85 2.85 2.91 2.89 2.78 2.83 2.85 2.87 2.86 2.85 2.85  Clarifier AHRT (hr) 1.40 1.38 1.39 1.41 1.39 1.40 1.39 1.39 1.39 1.14 1.14 1.10 1.12 1.12 1.13 1.13 1.13 1.15 1.14 1.14 1.14 1.14 1.14 1.14 1.16 1.15 1.11 1.13 1.14 1.15 1.15 1.14 1.14  MLE System #2  Date Day Jul 12/94 5 Jul 14/94 7 Jul 15/94 8 Jul 18/94 11 Jul 20/94 13 Jul 22/94 15 Jul 25/94 18 Jul 27/94 20 Aug 1/94 24 Aug 3/94 26 Aug 5/94 28 Aug 8/94 31 Aug 10/94 33 Aug 12/94 35 Aug 15/94 38 Aug 17/94 40 Aug 19/94 42 Aug 22/94 45 Aug 24/94 47 Aug 26/94 49 Aug 29/94 52 Aug 31/94 54 Sep 2/94 56 Sep 6/94 60 Sep 9/94 63 Sep 12/94 66 Sep 14/94 68 Sep 16/94 70 Sep 19/94 73 Sep 21/94 75 Sep 23/94 77 Sep 26/94 80 Sep 28/94 82 Sep 30/94 84 Oct 3/94 87 Oct 7/94 91 Oct 11/94 95 Oct 14/94 98 Oct 17/94 101 Oct 19/94 103 Oct 21/94 105 Oct 23/94 107 Oct 25/94 109 Oct 28/94 112 Nov 1/94 116 Nov 4/94 119 Nov 8/94 123 Nov 11/94 126  P04 Feed Cone (g P/I) 0.692 0.692 0.692 0.675 0.675 0.675 0.672 0.672 0.656 0.656 0.656 0.644 0.644 0.644 0.644 0.644 0.644 0.536 0.536 0.536 0.536 0.536 0.536 0.539 0.539 0.875 0.875 0.875 0.875 0.865 0.865 0.865 0.865 0.865 0.865 0.865 0.902 0.902 0.902 0.902 0.902 0.902 0.911 0.911 0.911 0.911 0.911 0.842  CH30H Feed Cone (ml/I) 0 0 0 0 0 0 0 0 0 0 0 0 0 15 5 5 10 10 20 20 20 30 40 50 50 50 50 50 50 50 50 50 50 50 50 50 50 60 60 60 70 70 50 25 36 47 69 88 182  NH4CI Feed Cone (g NH4CL/I) 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 24 62 62 110 110 138 138 138 138 111 111 111 111 111 0 0 44 93 95 122  NaHC03 Feed Cone (g/i) 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 80 80 80 80 80 80 80 80 80 80 80 80 80 0 0 0 80 80 80 80  MLE System #2  Date Nov 15/94 Nov 18/94 Nov 22/94 Nov 25/94 Nov 29/94 Dec 2/94 Dec 6/94 Dec 9/94 Dec 12/94 Dec 16/94 Dec 20/94 Dec 23/94 Dec 27/94 Dec 30/94 Jan 3/95 Jan 6/95 Jan 10/95 Jan 13/95 Jan 17/95 Jan 20/95 Jan 24/95 Jan 27/95 Jan 31/95 Feb 3/95 Feb 7/95 Feb 10/95 Feb 14/95 Feb 17/95 Feb 21/95 Feb 24/95 Feb 28/95 Mar 3/95 Mar 7/95  Day 130 133 137 140 144 147 151 154 157 161 165 168 172 175 179 182 186 189 193 196 200 203 207 210 214 217 221 224 228 231 235 238 242  P04 Feed Cone (g P/i) 0.842 0.842 0.842 0.842 1.000 1.000 1.000 1.000 1.000 1.032 1.032 1.032 1.032 0.989 0.989 0.989 0.989 0.989 0.989 0.989 0.951 0.951 0.951 0.951 0.955 0.955 0.951 0.951 0.951 0.951 0.951 0.974 0.974  CH30H Feed Cone (ml/I) 105 110 110 110 110 110 110 110 110 110 130 120 120 120 120 90 80 80 80 80 100 100 100 90 90 90 90 130 120 120 135 135 135  183  NH4CI Feed Cone (g NH4CL/I) 143 150 159 159 159 159 159 159 159 151 151 151 151 151 151 151 151 151 151 151 151 151 151 151 151 151 151 135 129 129 123 123 123  NaHC03 Feed Cone (g/i) 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80 80  MLE System #2  Date Day Jul 12/94 5 Jul 14/94 7 Jul 15/94 8 Jul 18/94 11 Jul 20/94 13 Jul 22/94 15 Jul 25/94 18 Jul 27/94 20 Aug 1/94 24 Aug 3/94 26 Aug 5/94 28 Aug 8/94 31 Aug 10/94 33 Aug 12/94 35 Aug 15/94 38 Aug 17/94 40 Aug 19/94 42 Aug 22/94 45 Aug 24/94 47 Aug 26/94 49 Aug 29/94 52 Aug 31/94 54 Sep 2/94 56 Sep 6/94 60 Sep 9/94 63 Sep 12/94 66 Sep 14/94 68 Sep 16/94 70 Sep 19/94 73 Sep 21/94 75 Sep 23/94 77 Sep 26/94 80 Sep 28/94 82 Sep 30/94 84 Oct 3/94 87 Oct 7/94 91 Oct 11/94 95 Oct 14/94 98 Oct 17/94 101 Oct 19/94 103 Oct 21/94 105 Oct 23/94 107 Oct 25/94 109 Oct 28/94 112 Nov 1/94 116 Nov 4/94 119 Nov 8/94 123 Nov 11/94 126  0-P04 (g P/d) 0.196 0.193 0.189 0.192 0.186 0.187 0.190 0.188 0.185 0.096 0.088 0.091 0.092 0.079 0.080 0.077 0.073 0.066 0.071 0.070 0.070 0.074 0.074 0.116 0.115 0.118 0.113 0.109 0.109 0.116 0.121 0.107 0.101 0.099 0.108 0.127 0.113 0.110 0.111 0.106 0.113 0.113 0.116 0.109 0.111 0.108  Anoxic Simulated Methanol Ammonia Ammonia COD Load Con'c Load NaHC03 (g COD/d) (mg N/l) (g N/d) g CaC03/d) 0 0 0 2.79 0 282 0 276 2.87 2.80 0 269 0 322 1.77 0 274 2.71 0 273 2.68 0 272 2.75 0 260 2.60 0 2.64 269 0 253 2.50 2.65 253 2.50 0.77 260 2.65 0.83 281 2.84 1.60 295 2.92 1.54 392 3.76 2.79 338 3.21 5.19 300 2.94 5.02 278 2.67 7.52 280 2.66 10.15 273 2.59 12.68 280 2.66 12.97 266 2.55 12.83 315 2.99 13.11 253 2.56 13.11 230 2.25 13.54 393 3.86 12.68 555 5.55 32.62 12.97 550 5.39 34.84 13.25 821 8.06 53.37 13.11 893 8.58 54.22 13.40 1074 10.43 59.60 12.83 1148 10.69 60.61 12.97 1054 10.13 48.24 13.11 1060 10.20 39.43 16.25 940 8.86 52.02 15.73 899 8.74 48.59 15.56 941 9.16 21.25 18.75 931 9.06 18.75 931 9.06 13.40 259 2.46 6.70 2.24 233 9.54 4.58 25.18 452 12.32 671 6.72 37.38 18.49 7.31 36.82 758 24.83 933 8.81 38.47 184  Anoxic ORF (mV)  17 -2 -18 -23 -57 -41 -42 -38 -48 -163 -208 -222 -172 -113 -101 -100 -102 -67 -82 -73 -77 -74 -112 -85 -107 -148 -153 -58 -61 -64 -87 -112  MLE System #2  Date Day Nov 15/94 130 Nov 18/94 133 Nov 22/94 137 Nov 25/94 140 Nov 29/94 144 Dec 2/94 147 Dec 6/94 151 Dec 9/94 154 Dec 12/94 157 Dec 16/94 161 Dec 20/94 165 Dec 23/94 168 Dec 27/94 172 Dec 30/94 175 Jan 3/95 179 Jan 6/95 182 Jan 10/95 186 Jan 13/95 189 Jan 17/95 193 Jan 20/95 196 Jan 24/95 200 Jan 27/95 203 Jan 31/95 207 Feb 3/95 210 Feb 7/95 214 Feb 10/95 217 Feb 14/95 221 Feb 17/95 224 Feb 21/95 228 Feb 24/95 231 Feb 28/95 235 Mar 3/95 238 Mar 7/95 242  0-P04 (g P/d) 0.101 0.101 0.106 0.096 0.121 0.134 0.116 0.121 0.119 0.125 0.139 0.122 0.124 0.136 0.114 0.137 0.116 0.119 0.135 0.128 0.128 0.121 0.125 0.118 0.119 0.118 0.127 0.117 0.123 0.116 0.117 0.121 0.119  Anoxic Simulated Methanol Ammonia Ammonia COD Load Con'c Load NaHC03 (g COD/d) (mg N/l) (g N/d) g CaC03/d) 28.73 1007 9.90 41.73 31.35 1069 10.53 45.62 30.10 1172 11.31 45.09 30.72 1166 11.25 46.92 30.72 1181 11.39 50.32 30.72 1250 11.43 49.79 30.41 1195 11.17 48.95 30.41 1211 11.08 48.83 29.47 1181 11.04 53.86 32.60 1174 10.97 45.51 39.64 1228 11.49 48.94 37.28 1226 11.59 52.16 35.57 1216 11.38 40.41 35.57 1148 10.85 50.48 35.91 1152 11.13 33.13 26.93 1102 10.41 39.28 23.03 1179 11.50 45.75 24.17 1244 11.38 36.62 24.17 1291 11.83 39.88 23.94 1285 11.65 52.90 30.50 1200 11.35 49.14 30.78 1240 11.24 46.60 30.21 1194 11.28 44.03 27.19 1177 11.84 50.90 27.45 1364 11.41 48.04 27.19 1229 11.26 45.69 27.45 1216 11.38 56.41 30.01 1144 10.48 46.28 26.68 1141 10.69 48.50 26.33 1180 10.22 48.84 30.40 996 9.62 12.13 30.40 1010 9.45 39.31 31.55 1050 9.94 43.68  185  Anoxic ORI (mV) -134 -165 -172 -170 -174 -181 -176 -180 -164 -168 -173 -165 -175 -173 -308 -322 -331 -315 -225 -151 -188 -205 -185 -187 -207 -197 -168 -174 -180 -145 -197 -205 -211  MLE System #2  Day Date Jul 12/94 5 Jul 14/94 7 Jul 15/94 8 Jul 18/94 11 Jul 20/94 13 Jul 22/94 15 Jul 25/94 18 Jul 27/94 20 Aug 1/94 24 Aug 3/94 26 Aug 5/94 28 Aug 8/94 31 33 Aug 10/94 Aug 12/94 35 Aug 15/94 38 Aug 17/94 40 Aug 19/94 42 Aug 22/94 45 Aug 24/94 47 Aug 26/94 49 Aug 29/94 52 Aug 31/94 54 56 Sep 2/94 Sep 6/94 60 63 Sep 9/94 Sep 12/94 66 Sep 14/94 68 Sep 16/94 70 Sep 19/94 73 Sep 21/94 75 Sep 23/94 77 Sep 26/94 80 Sep 28/94 82 Sep 30/94 84 Oct 3/94 87 Oct 7/94 91 95 Oct 11/94 Oct 14/94 98 Oct 17/94 101 Oct 19/94 103 Oct 21/94 105 Oct 23/94 107 Oct 25/94 109 Oct 28/94 112 Nov 1/94 116 Nov 4/94 119 Nov 8/94 123 Nov 11/94 126  Anoxic PH  7.8 7.7 7.6 7.6 7.6 7.7 7.7 7.8 7.9 8.1 8.2 8.2 8.1 8.2 8.1 7.9 7.9 8.0 7.9 8.0 7.9 7.9 7.9 8.1 8.2 8.0 8.0 8.1 8.3 8.0 8.0 8.2 8.1 8.2  Aerobic DO. (mg/l) 4.3 3.6 3.8 2.2 3.9 3.3 3.4 3.5 2.8 4.5 2.7 3.5 5.9 5.5 4.2 4.1 3.3 3.3 3.6 3.6 2.6 3.4 2.2 2.9 2.9 2.1 3.4 1.6 1.4 3.0 1.9 2.4 3.1 3.2 3.7 4.2 3.4 5.0 5.3 5.5 7.1 5.4 3.2 2.6 3.5 2.5  Aerobic PH  Anoxic Anoxic Free Aerobic \erobic Fre NH4 Ammonia NH4 Ammonia (mg N/l) (mg N/l) (mg N/l) (mg N/l) 8  7.5 7.6 7.5 7.5 7.5 7.5 7.5 7.5 7.5 7.5 7.9 7.8 7.5 7.5 7.5 7.5 7.6 7.7 7.8 7.9 8.0 8.2 8.1 8.1 8.2 7.7 7.6 7.6 7.7 7.6 7.6 7.6 7.6 7.7 7.6 7.9 7.8 8.1 8.3 8.5 7.9 7.6 7.5 7.7 7.6 186  44 66 47 40 47 41 40 37 36 33 34 31 35 30 27 47 65 68 95 105 144 195 247 361 174 164 285 349 522 305 43 65 98 84 96  0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.6 0.9 0.6 0.7 0.6 0.8 0.7 0.9 1.0 1.6 1.8 2.0 1.4 1.6 2.2 2.0 2.1 3.6 3.2 5.4 5.9 7.4 10.9 8.2 9.6 10.7 13.1 24.5 22.1 1.6 2.4 5.7 3.9 5.6  3 2 1 2 1 9 9 3 5 6 16 32 9 1 1 1 1 0 0 0 0 0 0 0 0 1 0 0 3 1 14 40 64 268 69 61 206 241 477 301 7 5 9 2 2  0.0 0.0 0.0 0.0 0.0 0.1 0.1 0.0 0.1 0.1 0.5 0.8 0.1 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 0.2 0.6 1.0 5.2 1.1 1.8 5.0 11.3 34.6 33.2 0.2 0.1 0.1 0.0 0.0  MLE System #2  Date Nov 15/94 Nov 18/94 Nov 22/94 Nov 25/94 Nov 29/94 Dec 2/94 Dec 6/94 Dec 9/94 Dec 12/94 Dec 16/94 Dec 20/94 Dec 23/94 Dec 27/94 Dec 30/94 Jan 3/95 Jan 6/95 Jan 10/95 Jan 13/95 Jan 17/95 Jan 20/95 Jan 24/95 Jan 27/95 Jan 31/95 Feb 3/95 Feb 7/95 Feb 10/95 Feb 14/95 Feb 17/95 Feb 21/95 Feb 24/95 Feb 28/95 Mar 3/95 Mar 7/95  Day 130 133 137 140 144 147 151 154 157 161 165 168 172 175 179 182 186 189 193 196 200 203 207 210 214 217 221 224 228 231 235 238 242  Anoxic PH 8.2 8.4 8.3 8.2 8.4 8.4 8.5 8.4 8.3 8.4 8.3 8.4 8.3 8.4 8.1 8.2 8.2 8.1 8.2 8.4 8.4 8.3 8.4 8.5 8.4 8.4 8.4 8.5 8.4 8.5 8.4 8.4 8.3  Aerobic DO. (mg/l) 3.1 3.1 2.9 2.7 3.2 3.3 3.3 3.6 3.0 3.0 1.9 3.0 2.7 3.4 2.6 3.7 2.5 2.7 2.1 2.8 2.4 2.1 2.8 2.0 2.1 2.1 2.1 2.6 2.4 3.1 3.7 3.0 2.7  Aerobic pH 7.6 7.6 7.5 7.5 7.6 7.6 7.7 7.6 7.6 7.7 7.8 7.9 7.8 8.0 7.6 7.6 7.9 7.6 7.6 7.7 7.6 7.6 7.3 7.6 7.4 7.5 7.7 7.9 7.5 7.7 7.6 7.6 7.4  187  Anoxic Anoxic Free Aerobic \erobic Fre< Ammonia NH4 Ammonia NH4 (mg N/l) (mg N/l) (mg N/l) (mg N/l) 107 6.3 1 0.0 0.1 127 11.4 4 0.1 9.3 12 129 0.1 119 7.0 5 165 14.8 8 0.1 165 14.8 10 0.2 12 0.2 166 18.3 15 0.2 165 14.8 20 0.3 151 10.9 10.3 12 0.2 115 0.4 11.0 18 152 0.4 143 12.8 13 0.4 134 9.7 18 13.9 22 0.8 155 1.4 199 9.3 90 2.6 251 14.7 172 144 4.3 237 13.8 341 16.0 216 3.3 2.1 246 14.4 134 38 0.7 138 12.4 43 0.7 139 12.4 0.6 151 10.9 37 71 0.6 171 15.3 0.7 164 18.1 44 0.5 170 15.2 53 28 0.3 138 12.4 25 0.5 143 12.8 0.1 102 11.2 3 13 0.2 130 11.6 0.1 109 12.0 5 102 9.1 6 0.1 103 9.2 7 0.1 5 0.0 114 8.3  MLE System #2  Date Day Jul 12/94 5 Jul 14/94 7 Jul 15/94 8 Jul 18/94 11 Jul 20/94 13 Jul 22/94 15 Jul 25/94 18 Jul 27/94 20 Aug 1/94 24 Aug 3/94 26 Aug 5/94 28 Aug 8/94 31 Aug 10/94 33 Aug 12/94 35 Aug 15/94 38 Aug 17/94 40 Aug 19/94 42 Aug 22/94 45 Aug 24/94 47 Aug 26/94 49 Aug 29/94 52 Aug 31/94 54 56 Sep 2/94 Sep 6/94 60 63 Sep 9/94 Sep 12/94 66 Sep 14/94 68 Sep 16/94 70 73 Sep 19/94 Sep 21/94 75 Sep 23/94 77 Sep 26/94 80 Sep 28/94 82 Sep 30/94 84 87 Oct 3/94 Oct 7/94 91 Oct 11/94 95 Oct 14/94 98 Oct 17/94 101 Oct 19/94 103 Oct 21/94 105 Oct 23/94 107 Oct 25/94 109 Oct 28/94 112 Nov 1/94 116 Nov 4/94 119 Nov 8/94 123 Nov 11/94 126  Effluent NH4 (mg N/l)  0 0 5 8 2 5 6 14 33 6 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3 0 15 38 66 272 66 61 195 282 477 291 4 4 9 1 2  Anoxic NOx (mg N/l)  Aerobic NOx (mg N/l)  Effluent NOx (mg N/l)  139 148 187 205 210 203 174 158 122 95 19 0 0 1 0 36 74 132 224 327 365 410 364 227 236 306 113 1  213 237 236 240 251 251 316 277 231 233 237 180 189 226 243 250 246 209 192 152 128 47 35 34 31 28 77 125 214 344 388 487 514 460 330 375 415 191 29  245 249 322 281 234 233 252 179 187 228 245 249 246 211 201 157 130 49 37 35 33 30 79 119 214 298 401 489 526 480 337 382 415 201 30  0 63 85 85 119 57  17 103 145 180 202 179  18 112 144 176 205 172  188  Anoxic N02 (mg N/l)  Aerobic N02 (mg N/l)  Effluent N02 (mg N/l)  2.8 11.6 15.5  17.3  2.9 9.1  5.7 3.9 14.2  6.1 4.2 13.5  4.8 1.0  5.3 1.6  5.3 1.4  2.5 2.3  1.3 0.6  0.8 0.3  5.5 5.4 0.3 0.1  0.3 0.4 0.8 0.7  0.2 0.2 0.3 0.3  0.1 0.2 0.2 0.2 0.4 0.3 0.7 0.3 0.2 0.4 0.4 0.2 0.2  0.6 0.5 1.4 0.4 9.8 2.3 17.4 13.9 7.0 25.7 34.0 22.6 18.5 7.5  0.2 0.2 0.9 0.2 10.6 3.6 17.6 15.0 11.5 26.7 36.4 22.6 18.6 8.0  0.1 0.3 0.5 1.8 0.9 2.7  7.5 8.5 11.8 36.3 10.0 31.8  8.3 10.6 13.0 35.4 9.9 31.5  6.5  MLE System #2  Date Nov 15/94 Nov 18/94 Nov 22/94 Nov 25/94 Nov 29/94 Dec 2/94 Dec 6/94 Dec 9/94 Dec 12/94 Dec 16/94 Dec 20/94 Dec 23/94 Dec 27/94 Dec 30/94 Jan 3/95 Jan 6/95 Jan 10/95 Jan 13/95 Jan 17/95 Jan 20/95 Jan 24/95 Jan 27/95 Jan 31/95 Feb 3/95 Feb 7/95 Feb 10/95 Feb 14/95 Feb 17/95 Feb 21/95 Feb 24/95 Feb 28/95 Mar 3/95 Mar 7/95  Day 130 133 137 140 144 147 151 154 157 161 165 168 172 175 179 182 186 189 193 196 200 203 207 210 214 217 221 224 228 231 235 238 242  Effluent NH4 (mg N/l) 1 5 10 4 7 9 12 16 23 12 20 11 18 23 89 167 150 217 129 39 42 37 67 41 53 26 25 3 13 4 6 8 5  Anoxic NOx (mg N/l) 1 1 1 1 0 0 0 0 1 0 0 0 1 1 0 1 0 0 0 115 1 0 1 1 1 0 1 1 2 54 0 0 1  Aerobic NOx (mg N/l) 123 117 100 93 123 117 124 123 108 90 86 106 97 101 60 81 81 69 104 283 152 131 141 155 136 143 165 146 158 229 95 102 105  189  Effluent NOx (mg N/l) 127 118 90 89 128 126 127 130 105 95 86 114 99 106 60 75 69 60 96 268 140 122 142 149 129 137 147 143 148 219 94 97 99  Anoxic Aerobic N02 N02 (mg N/l) (mg N/l) 1.1 28.9 43.0 0.1 48.0 0.2 0.1 44.0 69 0.1 0.0 74 0.0 80 73 0.0 0.3 66 57 0.0 68 0.0 0.0 61 0.4 66 37 0.1 0.0 37 0.3 54 0.0 55 0.0 48.0 72 0.0 64.0 167 0.3 86 0.0 78 0.8 85 96 0.7 85 0.3 0.0 88 0.7 98 0.2 83 0.8 80 117 29.0 0.0 78 63 0.0 0.2 64  Effluent N02 (mg N/l) 29.4 43.0 40.0 42.0 72 78 84 77 64 60 73 64 70 38 37 50 47 42 66 160 80 71 85 92 80 84 86 84 75 113 77 61 59  MLE System #2  Date Jul 12/94 Jul 14/94 Jul 15/94 Jul 18/94 Jul 20/94 Jul 22/94 Jul 25/94 Jul 27/94 Aug 1/94 Aug 3/94 Aug 5/94 Aug 8/94 Aug 10/94 Aug 12/94 Aug 15/94 Aug 17/94 Aug 19/94 Aug 22/94 Aug 24/94 Aug 26/94 Aug 29/94 Aug 31/94 Sep 2/94 Sep 6/94 Sep 9/94 Sep 12/94 Sep 14/94 Sep 16/94 Sep 19/94 Sep 21/94 Sep 23/94 Sep 26/94 Sep 28/94 Sep 30/94 Oct 3/94 Oct 7/94 Oct 11/94 Oct 14/94 Oct 17/94 Oct 19/94 Oct 21/94 Oct 23/94 Oct 25/94 Oct 28/94 Nov 1/94 Nov 4/94 Nov 8/94 Nov 11/94  Day 5 7 8 11 13 15 18 20 24 26 28 31 33 35 38 40 42 45 47 49 52 54 56 60 63 66 68 70 73 75 77 80 82 84 87 91 95 98 101 103 105 107 109 112 116 119 123 126  Anoxic 0-P04 (mg P/l)  Aerobic 0-P04 (mg P/l)  1.4 7.2 7.0 6.6 6.3 5.6 4.7 4.3 3.8 3.2 2.3 1.8 2.2 2.2 2.5 3.6 4.3 4.7 5.5 5.5 5.4 5.4 4.7 5.1 4.2 6.6 5.1 4.8  14.3 12.6 11.6 11.6 6.9 6.7 3.9 6.4 6.5 6.2 5.9 5.4 4.6 4.0 3.4 3.1 2.2 1.7 2.0 2.0 2.3 3.3 3.9 4.4 5.2 5.0 4.8 4.7 3.9 4.3 3.3 5.4 4.1 4.0  4.1  3.1  6.1 5.8 5.4 3.2  5.7 5.5 5.1 3.0  Anoxic TSS (mg/l)  Aerobic TSS (mg/l) 2504  Effluent TSS (mg/l)  Anoxic VSS (mg/l)  Aerobic VSS (mg/l) 1900  2992 2688 2372 2676 2860 2944 2776  31 62 78  2216 2016 1704 1912 1948 1944 1724  2484 2048  67 46  1512 1316  2692 3368 2400 2308 2400 2404 2564 2680 2820 2776 3040 3512 3640 3668 3376 3428 3296 3568 3504 3772 4048 4004 4132 4428 4664 4436 4632 4684  1884 1852 1660 1584 1696 1684 1652 1876 2024 2156 2440 2536 2696 2692 2560 2532 2528 2628 2776 2928 2860 2940 3032 2948 2960 2988 3152 3004  15 12 7 5 7 8 14 5 6 6 6 8 6 10 5 4 5 2 22 10 11 38 34 28 72 51 131 71  1884 1788 1660 1612 1652 1644 1768 1868 1980 1948 2220 2596 2728 2760 2568 2644 2564 2776 2788 3016 3244 3270 3360 3616 3844 3660 3824 3844  1316 1320 1160 1124 1188 1168 1172 1324 1424 1520 1808 1892 2056 2032 1928 1960 1976 2064 2200 2352 2308 2384 2456 2424 2436 2432 2616 2480  4020 3428 3368 3508 3536 4456  2324 2452 2392 2844 3200 3440  34 21 6 12 24 57  3252 2672 2640 2784 2840 3684  1892 1908 1876 2252 2592 2852  190  MLE System #2  Day Date Nov 15/94 130 Nov 18/94 133 Nov 22/94 137 Nov 25/94 140 Nov 29/94 144 Dec 2/94 147 Dec 6/94 151 Dec 9/94 154 Dec 12/94 157 Dec 16/94 161 Dec 20/94 165 Dec 23/94 168 Dec 27/94 172 Dec 30/94 175 Jan 3/95 179 Jan 6/95 182 Jan 10/95 186 Jan 13/95 189 Jan 17/95 193 Jan 20/95 196 Jan 24/95 200 Jan 27/95 203 Jan 31/95 207 Feb 3/95 210 Feb 7/95 214 Feb 10/95 217 Feb 14/95 221 Feb 17/95 224 Feb 21/95 228 Feb 24/95 231 Feb 28/95 235 Mar 3/95 238 Mar 7/95 242  Anoxic 0-P04 (mg P/l) 2.7 2.5 2.8 2.8 2.7 2.7 2.8 3.3 3.7 3.9 3.5 2.9 3.9 3.5 3.0 5.3 5.9 5.5 4.9 2.8 3.7 3.8 4.1 3.9 4.9 4.6 3.3 3.6 4.1 3.8 3.9 3.8 3.9  Aerobic 0-P04 (mg P/l) 2.5 2.2 2.3 2.1 2.3 2.5 2.5 2.7 3.0 3.1 2.8 2.5 3.2 2.8 2.4 4.4 5.0 4.4 4.4 3.6 3.6 3.4 4.2 3.9 4.8 4.5 3.5 3.3 4.3 4.0 3.9 3.5 3.5  Anoxic TSS (mg/l) 5184 5568 5688 5572 5748 5508 5736 5900 5700 5804 5928 6248 6328 6548 6276 6360 6304 5788 6192 6360 6700 7160 6948 7560 8120 7860 8220 8088 8428 8416 8736 8572 8904  191  Aerobic TSS (mg/l) 4120 4356 4220 4748 5136 4884 4964 4716 5136 4424 4988 4940 5392 5412 5436 5248 5032 4772 5048 5524 5584 5908 6220 6216 6556 6508 6880 7240 7276 7080 7504 7452 7656  Effluent TSS (mg/l) 35 19 33 112 29 39 29 20 25 18 25 33 45 32 52 30 56 110 18 84 52 18 39 14 38 132 15 33 19 15 19 26 22  Anoxic VSS (mg/l) 4376 4760 4804 4776 4948 4788 5028 5208 5052 5148 5304 5600 5688 5904 5684 5748 5712 5216 5560 5656 5960 6404 6228 6796 7284 7048 7320 7212 7516 7524 7816 7672 7948  Aerobic VSS (mg/l) 3488 3696 3572 4064 4412 4256 4248 4164 4544 3928 4456 4428 4832 4868 4920 4712 4560 4284 4544 4852 4960 5258 5584 5588 5872 5824 6128 6448 6476 6320 6684 6660 6820  MLE System #2  Day Date Jul 12/94 5 Jul 14/94 7 Jul 15/94 8 Jul 18/94 11 13 Jul 20/94 Jul 22/94 15 Jul 25/94 18 Jul 27/94 20 Aug 1/94 24 Aug 3/94 26 Aug 5/94 28 31 Aug 8/94 Aug 10/94 33 Aug 12/94 35 Aug 15/94 38 Aug 17/94 40 Aug 19/94 42 Aug 22/94 45 47 Aug 24/94 Aug 26/94 49 Aug 29/94 52 Aug 31/94 54 Sep 2/94 56 Sep 6/94 60 Sep 9/94 63 Sep 12/94 66 Sep 14/94 68 Sep 16/94 70 Sep 19/94 73 Sep 21/94 75 Sep 23/94 77 Sep 26/94 80 Sep 28/94 82 Sep 30/94 84 Oct 3/94 87 Oct 7/94 91 Oct 11/94 95 Oct 14/94 98 Oct 17/94 101 Oct 19/94 103 Oct 21/94 105 Oct 23/94 107 Oct 25/94 109 Oct 28/94 112 Nov 1/94 116 Nov 4/94 119 Nov 8/94 123 Nov 11/94 126  Effluent VSS (mg/l)  Anoxic BOD5 (mg/l)  Aerobic BOD5 (mg/l)  Effluent BOD5 (mg/l)  Anoxic COD (mg/l)  25 40 48  Aerobic COD (mg/l)  417  Effluent COD (mg/l)  376 390  38 29 12 8 •6 5 6 6 9 4 5 5 5 6 6 9 4 4 4 2 16 9 8 26 30 24 50 43 97 56  31  22  5  28 17 6 11 21 49 192  5  318  335  335  368 368  351 351  335 351  479 446  446 412  429 429  420 472 429 429  386 403 394 394  403 420 412 394  333 300  300 283  300 300  302 366  318 318  350 318  430 455 473 438  445 438 473 456  445 438 473 419  582  492  492  620 397 336 309 326 341  515 368 323 235 281 306  526 385 321 270 281 270  MLE System #2  Date Nov 15/94 Nov 18/94 Nov 22/94 Nov 25/94 Nov 29/94 Dec 2/94 Dec 6/94 Dec 9/94 Dec 12/94 Dec 16/94 Dec 20/94 Dec 23/94 Dec 27/94 Dec 30/94 Jan 3/95 Jan 6/95 Jan 10/95 Jan 13/95 Jan 17/95 Jan 20/95 Jan 24/95 Jan 27/95 Jan 31/95 Feb 3/95 Feb 7/95 Feb 10/95 Feb 14/95 Feb 17/95 Feb 21/95 Feb 24/95 Feb 28/95 Mar 3/95 Mar 7/95  Day 130 133 137 140 144 147 151 154 157 161 165 168 172 175 179 182 186 189 193 196 200 203 207 210 214 217 221 224 228 231 235 238 242  Anoxic Effluent BOD5 VSS (mg/l) (mg/l) 32 14 29 97 25 79 34 27 74 20 21 16 22 30 88 39 28 47 26 115 90 53 100 18 75 113 46 16 113 33 14 28 53 118 9 15 27 17 34 13 ' 16 61 19 19  Aerobic BOD5 (mg/l)  Effluent BOD5 (mg/l)  9  11  7  12  17  20  19  17  14  15  10  13  7 10  9 11  14  13  13  15  193  Anoxic COD (mg/l) 341  Aerobic COD (mg/l) 274  Effluent COD (mg/l) 291  378 281 353 320 300 333  167 205 207 200 120 94  234 234 202 196 115 97  476 407 441 406 504 303 302 433 346  194 202 196 248 367 146 145 250 180  292 233 226 286 367 199 153 300 187  333 333  206 199  214 240  356 356 296 348 328 306  167 248  206 216 137  186 184 160  205  MLE System #2  Date Day Jul 12/94 5 7 Jul 14/94 Jul 15/94 8 Jul 18/94 11 Jul 20/94 13 Jul 22/94 15 Jul 25/94 18 20 Jul 27/94 Aug 1/94 24 Aug 3/94 26 Aug 5/94 28 Aug 8/94 31 Aug 10/94 33 Aug 12/94 35 Aug 15/94 38 Aug 17/94 40 42 Aug 19/94 Aug 22/94 45 Aug 24/94 47 Aug 26/94 49 Aug 29/94 52 Aug 31/94 54 Sep 2/94 56 Sep 6/94 60 Sep 9/94 63 Sep 12/94 66 Sep 14/94 68 Sep 16/94 70 Sep 19/94 73 Sep 21/94 75 Sep 23/94 77 Sep 26/94 80 Sep 28/94 82 Sep 30/94 84 Oct 3/94 87 Oct 7/94 91 Oct 11/94 95 98 Oct 14/94 Oct 17/94 101 Oct 19/94 103 Oct 21/94 105 Oct 23/94 107 Oct 25/94 109 Oct 28/94 112 Nov 1/94 116 Nov 4/94 119 Nov 8/94 123 Nov 11/94 126  Anoxic VSS/TSS  Aerobic VSS/TSS 0.76  Effluent VSS/TSS  0.74 0.75 0.72 0.71 0.68 0.66 0.62  0.81 0.65 0.62  0.61 0.64  0.57 0.63  0.70 0.53 0.69 0.70 0.69 0.68 0.69 0.70 0.70 0.70 0.73 0.74 0.75 0.75 0.76 0.77 0.78 0.78 0.80 0.80 0.80 0.82 0.81 0.82 0.82 0.83 0.83 0.82  0.70 0.71 0.70 0.71 0.70 0.69 0.71 0.71 0.70 0.71 0.74 0.75 0.76 0.75 0.75 0.77 0.78 0.79 0.79 0.80 0.81 0.81 0.81 0.82 0.82 0.81 0.83 0.83  0.80 0.67 0.86 1.00 0.86 0.75 0.64 0.80 0.83 0.83 0.83 0.75 1.00 0.90 0.80 1.00 0.80 1.00 0.73 0.90 0.73 0.68 0.88 0.86 0.69 0.84 0.74 0.79  0.81 0.78 0.78 0.79 0.80 0.83  0.81 0.78 0.78 0.79 0.81 0.83  0.82 0.81 1.00 0.92 0.88 0.86  194  Aerobic Effluent Anoxic N02/NOx N02/NOx N02/NOx  0.01 0.07  0.07  0.02 0.06  0.02 0.02 0.08  0.02 0.02  0.02 0.00  0.02 0.01  0.02 0.01  0.01 0.01  0.01 0.00  0.00 0.00  0.06 0.28 0.75 0.50  0.00 0.01 0.02 0.02  0.00 0.00 0.01 0.01  0.33 0.01 0.00  0.02 0.01 0.01  0.01 0.00 0.01  0.00 0.00  0.03 0.01  0.04 0.01  0.00 0.00 0.00 0.00 0.00 0.00 0.20  0.03 0.02 0.08 0.09 0.05 0.10 0.26  0.03 0.02 0.08 0.10 0.05 0.09 0.27  0.00 0.00 0.01 0.02 0.01 0.05  0.44 0.08 0.08 0.20 0.05 0.18  0.46 0.09 0.09 0.20 0.05 0.18  MLE System #2  Date Nov 15/94 Nov 18/94 Nov 22/94 Nov 25/94 Nov 29/94 Dec 2/94 Dec 6/94 Dec 9/94 Dec 12/94 Dec 16/94 Dec 20/94 Dec 23/94 Dec 27/94 Dec 30/94 Jan 3/95 Jan 6/95 Jan 10/95 Jan 13/95 Jan 17/95 Jan 20/95 Jan 24/95 Jan 27/95 Jan 31/95 Feb 3/95 Feb 7/95 Feb 10/95 Feb 14/95 Feb 17/95 Feb 21/95 Feb 24/95 Feb 28/95 Mar 3/95 Mar 7/95  Day 130 133 137 140 144 147 151 154 157 161 165 168 172 175 179 182 186 189 193 196 200 203 207 210 214 217 221 224 228 231 235 238 242  Anoxic Aerobic Effluent Aerobic Effluent Anoxic VSS/TSS VSS/TSS VSS/TSS N02/NOX N02/NOx N02/NOx 0.84 0.85 0.91 1.10 0.23 0.23 0.10 0.37 0.36 0.85 0.74 0.85 0.44 0.20 0.48 0.85 0.88 0.84 0.47 0.47 0.86 0.87 0.10 0.86 0.00 0.56 0.56 0.86 0.86 0.86 0.62 0.87 0.00 0.63 0.87 0.87 0.00 0.65 0.66 0.88 0.86 0.93 0.59 0.59 0.88 0.88 1.00 0.00 0.61 0.88 0.84 0.30 0.61 0.89 0.63 0.63 0.89 0.89 0.00 0.89 0.00 0.79 0.85 0.89 0.89 0.88 0.56 0.90 0.91 0.00 0.58 0.90 0.71 0.90 0.87 0.40 0.68 0.90 0?10" 0.37 0.36 0.90 0.90 0.88 0.62 0.62 0.91 0.91 0.90 0.00 0.67 0.67 0.90 0.90 0.87 0.30 0.95 0.00 0.68 0.68 0.91 0.91 0.90 0.90 0.91 0.00 0.70 0.70 0.69 0.69 0.90 0.90 1.00 0.00 0.56 0.59 0.60 0.89 0.88 0.89 0.89 0.89 0.88 0.30 0.57 0.57 0.89 0.89 0.89 0.00 0.60 0.58 0.60 0.60 0.90 0.90 0.85 0.80 0.90 0.90 1.00 0.70 0.62 0.62 0.90 0.90 0.30 0.63 0.62 0.74 0.61 0.90 0.89 0.89 0.00 0.62 0.89 0.89 0.60 0.70 0.59 0.59 0.89 0.89 0.82 0.20 0.57 0.59 0.51 0.89 0.89 0.89 0.40 0.51 0.87 0.89 0.89 0.54 0.51 0.52 0.89 0.84 0.00 0.82 ' 0.82 0.89 0.89 0.73 0.00 0.62 0.63 oio 0.89 0.89 0.86 0.20 0.61 0.60  195  MLE System #2  Date Day Jul 12/94 5 Jul 14/94 7 Jul 15/94 8 Jul 18/94 11 Jul 20/94 13 Jul 22/94 15 Jul 25/94 18 Jul 27/94 20 Aug 1/94 24 Aug 3/94 26 Aug 5/94 28 Aug 8/94 31 Aug 10/94 33 Aug 12/94 35 Aug 15/94 38 Aug 17/94 40 Aug 19/94 42 Aug 22/94 45 Aug 24/94 47 Aug 26/94 49 Aug 29/94 52 Aug 31/94 54 Sep 2/94 56 Sep 6/94 60 Sep 9/94 63 Sep 12/94 66 Sep 14/94 68 Sep 16/94 70 73 Sep 19/94 Sep 21/94 75 Sep 23/94 77 Sep 26/94 80 Sep 28/94 82 Sep 30/94 84 Oct 3/94 87 Oct 7/94 91 Oct 11/94 95 98 Oct 14/94 Oct 17/94 101 Oct 19/94 103 Oct 21/94 105 Oct 23/94 107 Oct 25/94 109 Oct 28/94 112 Nov 1/94 116 Nov 4/94 119 Nov 8/94 123 Nov 11/94 126  Anoxic NH4 Removal Rate (mg N/d)  325 -117 -48 85 456 278 91 36 97 233 246 340 501 398 322 492 865 487 1598 1444 1368 -114 -3390 1083 1012 975 1525 -583 1234 -700 -222 500 579 1671 2451  Aerobic NH4 Removal Rate (mg N/d)  2023 2434 2797 2827 3297 2927 2844 2629 2560 2360 2410 2212 2489 2155 1930 3359 4686 4905 6431 7125 8914 10388 12851 6347 7125 7118 5553 7212 3006 265 2391 4030 6042 5615 6334 196  %  %  %  Anoxic NH4 Removal  Aerobic NH4 Removal  System NH4 Removal  64.5 50.9 81.3 98.0 97.7 98.3 98.8 98.9 99.2 99.7 98.8 99.4 99.1 99.3 99.3 98.9 99.5 99.9 97.3 99.1 '. 90.3 79.2 74.1 25.4 60.0 62.5 27.7 30.9 8.6 1.3 83.7 92.3 90.8 97.6 97.9  100 100 98 97 99 98 98 95 87 98 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 100 99 97 94 74 93 93 79 70 49 -12 98 99 99 100 100  9.4 -2.5 -1.4 2.9 11.9 8.5 3.1 1.4 3.6 9.0 9.2 13.2 16.6 15.5 14.2 12.7 15.5 9.0 19.5 16.7 12.2 -0.9 -24.3 4.1 7.9 7.9 7.1 -2.6 3.4 -3.6 -8.4 10.3 8.0 22.5 27.5  Anoxic NOx Load (mg N/d)  11020 11740 14240 15098 15527 15499 12992 11925 9441 7955 2934 2178 2113 1927 1742 4784 7763 13302 20438 22708 28501 29613 27746 19608 21942 24660 11533 1647 969 5843 8224 10371 11820 10314  MLE System #2  Date Nov 15/94 Nov 18/94 Nov 22/94 Nov 25/94 Nov 29/94 Dec 2/94 Dec 6/94 Dec 9/94 Dec 12/94 Dec 16/94 Dec 20/94 Dec 23/94 Dec 27/94 Dec 30/94 Jan 3/95 Jan 6/95 Jan 10/95 Jan 13/95 Jan 17/95 Jan 20/95 Jan 24/95 Jan 27/95 Jan 31/95 Feb 3/95 Feb 7/95 Feb 10/95 Feb 14/95 Feb 17/95 Feb 21/95 Feb 24/95 Feb 28/95 Mar 3/95 Mar 7/95  Day 130 133 137 140 144 147 151 154 157 161 165 168 172 175 179 182 186 189 193 196 200 203 207 210 214 217 221 224 228 231 235 238 242  Anoxic NH4 Removal Rate (mg N/d) 2709 2036 3168 3496 556 791 549 732 1910 2253 123 242 1304 -613 986 2041 2238 -1092 1210 2961 2901 1397 2222 1379 1389 1926 1061 2114 783 1559 1512 1364 774  Aerobic NH4 Removal Rate (mg N/d) 7185 8449 8009 7704 10749 10535 10493 10190 8918 8594 11182 11213 9888 11225 9187 6561 7711 10309 9259 8293 7996 9462 8319 9968 9510 9048 10048 8338 9766 8611 8049 8016 9116  197  % Anoxic NH4 Removal 27.2 18.9 26.4 30.3 4.7 6.6 4.6 6.1 15.6 19.0 1.0 1.9 10.2 -4.9 5.5 8.8 10.1 -4.0 5.6 20.5 20.0 10.0 13.4 9.2 9.1 14.5 8.0 19.7 6.7 14.7 15.0 13.7 7.5  % Aerobic NH4 Removal 99.1 96.8 90.6 95.8 95.1 93.9 92.7 90.8 86.6 89.5 88.0 90.8 86.5 85.7 54.5 30.9 38.8 36.3 45.1 72.2 68.8 75.3 58.2 72.9 68.5 79.5 82.3 97.0 89.9 95.4 94.1 93.2 95.6  % System NH4 Removal 100 100 99 100 99 99 99 99 98 99 98 99 99 98 92 85 87 83 90 97 97 97 94 97 96 98 98 100 99 100 99 99 100  Anoxic NOx Load (mg N/d) 7088 6855 5853 5362 7197 6847 7256 7197 6320 6644 6350 8112 7335 7547 4487 6057 5980 5095 7677 20888 11220 9670 10408 11304 9916 10426 12477 10909 11664 16902 7014 7530 7751  MLE System #2  (mg N/d)  Anoxic Specific Denitr Rate (mg N/d/ mg VSS)  1118 1019 550 313 443 757 462 578 692 1141 1571 2150 2099 1884 1720 2183 2404 3767 4860 324 3481 2046 2183 3865 5826 3404 3581 1580  0.119 0.114 0.066 0.039 0.054 0.092 0.052 0.062 0.070 0.117 0.142 0.166 0.154 0.137 0.134 0.165 0.188 0.271 0.349 0.021 0.215 0.125 0.130 0.214 0.303 0.186 0.187 0.082  969 1659 2514 4597 3669 6473  0.060 0.124 0.190 0.330 0.258 0.351  Anoxic Denitr Rate Date Jul 12/94 Jul 14/94 Jul 15/94 Jul 18/94 Jul 20/94 Jul 22/94 Jul 25/94 Jul 27/94 Aug 1/94 Aug 3/94 Aug 5/94 Aug 8/94 Aug 10/94 Aug 12/94 Aug 15/94 Aug 17/94 Aug 19/94 Aug 22/94 Aug 24/94 Aug 26/94 Aug 29/94 Aug 31/94 Sep 2/94 Sep 6/94 Sep 9/94 Sep 12/94 Sep 14/94 Sep 16/94 Sep 19/94 Sep 21/94 Sep 23/94 Sep 26/94 Sep 28/94 Sep 30/94 Oct 3/94 Oct 7/94 Oct 11/94 Oct 14/94 Oct 17/94 Oct 19/94 Oct 21/94 Oct 23/94 Oct 25/94 Oct 28/94 Nov 1/94 Nov 4/94 Nov 8/94 Nov 11/94  Day 5 7 8 11 13 15 18 20 24 26 28 31 33 35 38 40 42 45 47 49 52 54 56 60 63 66 68 70 73 75 77 80 82 84 87 91 95 98 101 103 105 107 109 112 116 119 123 126  (mg N/d)  Aerobic Specific Nitr Rate (mg N/d/ mg VSS)  10.1 8.7 3.9 2.1 2.9 4.9 3.6 4.8 7.3 14.3 53.6 98.7 99.3 97.7 98.8 45.6 31.0 28.3 23.8 1.4 12.2 6.9 7.9 19.7 26.6 13.8 31.0 95.9  2921 2970 2855 2741 2873 3123 2520 2442 2151 2367 2008 2485 2424 2199 1995 2962 3726 5990 8587 4458 8748 7424 7002 7269 9738 7823 5495 1870  0.222 0.225 0.246 0.244 0.242 0.267 0.215 0.184 0.151 0.156 0.111 0.131 0.118 0.108 0.103 0.151 0.189 0.290 0.390 0.190 0.379 0.311 0.285 0.300 0.400 0.322 0.210 0.075  93.2 62.1 83.0 95.0 85.1 104.9 87.5 91.9 83.3 100.0 82.4 111.6 96.6 101.3 102.6 87.2 79.1 121.9 130.0 62.0 88.6 56.6 40.4 29.0 82.0 68.7 27.4 8.0  0.24 0.07 0.06 0.11 0.10 0.18 0.40 0.42 0.80 1.28 4.32 5.95 6.07 6.80 7.53 2.83 1.63 0.97 0.65 0.58 0.47 0.43 0.47 0.67 0.74 0.64 1.35 11.39  100.0 28.4 30.6 44.3 31.0 62.8  1127 2657 4063 6540 5780 8314  0.060 0.139 0.217 0.290 0.223 0.292  5.6 93.0 93.0 98.2 100.5 128.5  13.83 1.15 1.16 1.19 1.56 2.41  Aerobic Nitr Rate  %  Anoxic Denitr  %  Aerobic Nitr  Anoxic COD:NOx Entering (mg COD/ mg N)  .  198  MLE System #2  Anoxic Denitr Rate Date Nov 15/94 Nov 18/94 Nov 22/94 Nov 25/94 Nov 29/94 Dec 2/94 Dec 6/94 Dec 9/94 Dec 12/94 Dec 16/94 Dec 20/94 Dec 23/94 Dec 27/94 Dec 30/94 Jan 3/95 Jan 6/95 Jan 10/95 Jan 13/95 Jan 17/95 Jan 20/95 Jan 24/95 Jan 27/95 Jan 31/95 Feb 3/95 Feb 7/95 Feb 10/95 Feb 14/95 Feb 17/95 Feb 21/95 Feb 24/95 Feb 28/95 Mar 3/95 Mar 7/95  Day 130 133 137 140 144 147 151 154 157 161 165 168 172 175 179 182 186 189 193 196 200 203 207 210 214 217 221 224 228 231 235 238 242  (mg N/d) 7020 6786 5784 5295 7197 6847 7256 7197 6252 6644 6350 8112 7250 7462 4487 5973 5980 5095 7677 11314 11137 9670 10324 11221 9834 10426 12391 10825 11497 12429 7014 7530 7667  Anoxic Specific Denitr Rate (mg N/d/ mg VSS) 0.321 0.285 0.241 0.222 0.291 0.286 0.289 0.276 0.247 0.258 0.239 0.290 0.255 0.253 0.158 0.208 0.209 0.195 0.276 0.400 0.374 0.302 0.332 0.330 0.270 0.296 0.339 0.300 0.306 0.330 0.179 0.196 0.193  Aerobic Nitr Rate  %  Anoxic Denitr 99.0 99.0 98.8 98.7 100.0 100.0 100.0 100.0 98.9 100.0 100.0 100.0 98.8 98.9 100.0 98.6 100.0 100.0 100.0 54.2 99.3 100.0 99.2 99.3 99.2 100.0 99.3 99.2 98.6 73.5 100.0 100.0 98.9  199  (mg N/d) 8347 8053 6852 6287 8519 8047 8556 8465 7392 7579 7251 9239 8253 8538 5117 6817 6853 5783 8730 14229 12753 11004 11798 12951 11132 11894 14146 12317 13151 14672 7965 8580 8766  Aerobic Specific Nitr Rate (mg N/d/ mg VSS) 0.239 0.218 0.192 0.155 0.193 0.189 0.201 0.203 0.163 0.193 0.163 0.209 0.171 0.175 0.104 0.145 0.150 0.135 0.192 0.293 0.257 0.209 0.211 0.232 0.190 0.204 0.231 0.191 0.203 0.232 0.119 0.129 0.129  %  Aerobic Nitr 115.1 92.3 77.5 78.1 75.4 71.7 75.6 75.4 71.8 78.9 57.1 74.8 72.2 65.2 30.3 32.1 34.4 20.4 42.6 123.8 109.7 87.5 82.5 94.8 80.2 104.5 115.9 143.3 121.1 162.5 93.1 99.7 91.9  Anoxic COD:NOx Entering (mg COD/ mg N) 4.05 4.57 5.14 5.73 4.27 4.49 4.19 4.23 4.66 4.91 6.24 4.60 4.85 4.71 8.00 4.45 3.85 4.74 3.15 1.15 2.72 3.18 2.90 2.41 2.77 2.61 2.20 2.75 2.29 1.56 4.33 4.04 4.07  MLE System #2  Anoxic Aerobic Aerobic COD:NOx Alk:NH4 Alk:NH4 Removed Added Nitrified Aerobic (mg COD/ (g CaC03/ (g CaC03/ SRT Date Day mg N) (days) ON) gN) Jul 12/94 5 Jul 14/94 7 Jul 15/94 8 Jul 18/94 11 Jul 20/94 13 Jul 22/94 15 Jul 25/94 18 Jul 27/94 20 Aug 1/94 24 10 Aug 3/94 26 10 Aug 5/94 28 10 Aug 8/94 31 10 Aug 10/94 33 10 Aug 12/94 35 2.37 Aug 15/94 38 0.75 Aug 17/94 40 1.50 Aug 19/94 42 5.10 20 Aug 22/94 45 3.48 20 Aug 24/94 47 3.69 20 Aug 26/94 49 11.23 20 Aug 29/94 52 8.68 20 Aug 31/94 54 10.88 20 Sep 2/94 56 8.89 20 Sep 6/94 60 8.07 20 Sep 9/94 63 6.03 20 Sep 12/94 66 6.11 20 Sep 14/94 68 6.96 13 Sep 16/94 70 7.62 13 Sep 19/94 73 6.20 13 Sep 21/94 75 5.28 5.87 8.76 13 Sep 23/94 77 3.44 6.46 5.82 13 Sep 26/94 80 2.73 6.62 6.22 13 Sep 28/94 82 40.49 6.32 12.16 13 Sep 30/94 84 3.85 5.71 6.81 13 Oct 3/94 87 6.27 5.67 8.16 13 Oct 7/94 91 5.94 4.76 6.89 13 Oct 11/94 95 3.39 3.87 5.42 13 Oct 14/94 98 2.79 5.87 5.34 13 Oct 17/94 101 4.62 5.56 6.21 13 Oct 19/94 103 4.35 2.32 3.87 13 Oct 21/94 105 11.87 13 Oct 23/94 107 Oct 25/94 109 13.83 13 Oct 28/94 112 4.04 13 Nov 1/94 116 3.80 5.49 6.20 13 Nov 4/94 119 2.68 5.56 5.72 13 Nov 8/94 123 5.04 5.04 6.37 13 Nov 11/94 126 3.84 4.37 4.63 13 200  System SRT (days)  Simulated Leachate Flow (l/d)  40.7 40.0 40.1 39.1 41.7 41.1 40.3 40.1 41.2 41.0 27.4 28.1 28.2 27.9 28.6 25.7 27.1 28.0 25.3 24.9 26.4 23.7 24.0 19.8 23.3  10.1 9.9 10.4 10.4 5.5 9.9 9.8 10.1 10.0 9.8 9.9 9.9 10.2 10.1 9.9 9.6 9.5 9.8 9.6 9.5 9.5 9.5 9.6 9.5 10.1 9.8 9.8 10.0 9.8 9.8 9.6 9.7 9.3 9.6 9.6 9.4 9.7 9.7 9.7  26.4 26.3 28.1 26.4 24.5 23.1  9.5 9.6 10.1 10.0 9.6 9.4  MLE System #2  Date Nov 15/94 Nov 18/94 Nov 22/94 Nov 25/94 Nov 29/94 Dec 2/94 Dec 6/94 Dec 9/94 Dec 12/94 Dec 16/94 Dec 20/94 Dec 23/94 Dec 27/94 Dec 30/94 Jan 3/95 Jan 6/95 Jan 10/95 Jan 13/95 Jan 17/95 Jan 20/95 Jan 24/95 Jan 27/95 Jan 31/95 Feb 3/95 Feb 7/95 Feb 10/95 Feb 14/95 Feb 17/95 Feb 21/95 Feb 24/95 Feb 28/95 Mar 3/95 Mar 7/95  Day 130 133 137 140 144 147 151 154 157 161 165 168 172 175 179 182 186 189 193 196 200 203 207 210 214 217 221 224 228 231 235 238 242  Anoxic Aerobic Aerobic COD:NOx Alk:NH4 Alk:NH4 Removed Added Nitrified Aerobic (mg COD/ (g CaC03/ (g CaC03/ SRT mg N) (days) ON) gN) 4.09 4.21 5.00 13 4.62 4.33 5.66 13 5.20 3.99 6.58 13 5.80 4.17 7.46 13 4.27 4.42 5.91 10 4.49 4.36 6.19 10 4.19 4.38 5.72 10 4.23 4.41 5.77 10 4.71 4.88 7.29 10 4.91 4.15 6.00 10 6.24 4.26 6.75 10 4.60 4.50 5.65 10 4.91 3.55 4.90 10 4.77 4.65 5.91 10 8.00 2.98 6.48 10 4.51 3.77 5.76 10 3.85 3.98 6.68 10 4.74 3.22 6.33 15 3.15 3.37 4.57 15 2.12 4.54 3.72 15 2.74 4.33 3.85 15 3.18 4.15 4.23 20 2.93 3.90 3.73 20 2.42 4.30 3.93 20 2.79 4.21 4.32 20 2.61 4.06 3.84 20 2.21 4.96 3.99 20 2.77 4.42 3.76 20 2.32 4,54 3.69 20 2.12 4.78 3.33 20 4.33 1.26 1.52 20 4.04 4.16 4.58 20 4.11 4.39 4.98 20  201  System SRT (days) 25.1 27.1 26.0 20.8 19.4 19.1 19.6 20.3 19.6 20.7 19.9 19.9 19.3 19.8 18.9 19.9 18.9 23.3 29.7 25.1 27.3 39.7 36.6 39.9 38.9 29.7 40.7 37.9 39.4 40.3 39.8 39.2 39.4  Simulated Leachate Flow (l/d) 9.8 9.8 9.6 9.6 9.6 9.1 9.3 9.1 9.3 9.3 9.4 9.5 9.4 9.4 9.7 9.4 9.8 9.2 9.2 9.1 9.5 9.1 9.5 10.1 8.4 9.2 9.4 9.2 9.4 8.7 9.7 9.4 9.5  MLE System #2  Date Day Jul 12/94 5 Jul 14/94 7 Jul 15/94 8 Jul 18/94 11 Jul 20/94 13 Jul 22/94 15 Jul 25/94 18 Jul 27/94 20 Aug 1/94 24 Aug 3/94 26 Aug 5/94 28 Aug 8/94 31 Aug 10/94 33 Aug 12/94 35 Aug 15/94 38 Aug 17/94 40 Aug 19/94 42 Aug 22/94 45 Aug 24/94 47 Aug 26/94 49 Aug 29/94 52 Aug 31/94 54 Sep 2/94 56 Sep 6/94 60 Sep 9/94 63 Sep 12/94 66 Sep 14/94 68 Sep 16/94 70 Sep 19/94 73 Sep 21/94 75 Sep 23/94 77 Sep 26/94 80 Sep 28/94 82 Sep 30/94 84 Oct 3/94 87 Oct 7/94 91 Oct 11/94 95 Oct 14/94 98 Oct 17/94 101 Oct 19/94 103 Oct 21/94 105 Oct 23/94 107 Oct 25/94 109 Oct 28/94 112 Nov 1/94 116 Nov 4/94 119 Nov 8/94 123 Nov 11/94 126  Clarifier Recycle Flow (l/d)  Clarifier Recycle Ratio  60.3 60.3 60.3 60.3 59.4 59.4 59.4 59.4 59.4 63.9 63.0 61.2 62.1 63.0 62.1 62.1 63.0 62.1 62.1 62.1 62.1 62.1 62.1 62.1 62.1 62.1 62.1 62.1 62.1 59.4 58.5 58.5 57.6 60.3 59.4 58.5 59.4 60.3 56.7  6.0 6.1 5.8 5.8 10.8 6.0 6.1 5.9 5.9 6.5 6.4 6.2 6.1 6.2 6.3 6.5 6.6 6.3 6.5 6.5 6.5 6.5 6.5 6.5 6.1 6.3 6.3 6.2 6.3 6.1 6.1 6.0 6.2 6.3 6.2 6.2 6.1 6.2 5.8  0.27 0.28 0.27 0.28 0.27 0.27 0.28 0.28 0.28 0.14 0.12 0.28 0.27 0.25 0.26 0.26 0.24 0.33 0.33 0.33 0.33 0.34 0.34 0.34 0.34 0.35 0.35 0.59 0,66 1.05 1.08 1.13 1.17 0.89 0.72 1.02 0.94 0.36 0.34  10.4 10.2 10.7 10.7 5.8 10.2 10.1 10.4 10.3 9.9 10.0 10.2 10.5 10.3 10.2 9.9 9.7 10.1 9.9 9.8 9.8 9.8 9.9 9.8 10.4 10.1 10.2 10.6 10.5 10.9 10.7 10.8 10.5 10.5 10.3 10.4 10.7 10.1 10.1  245 249 322 281 234 233 252 179 187 228 245 249 246 211 201 157 130 49 37 35 33 30 79 119 214 298 401 489 526 480 337 382 415 201 , 30  1.03 1.03 1.03 1.03 1.05 1.03 1.03 1.03 1.03 1.01 1.01 1.03 1.03 1.02 1.03 1.03 1.03 1.03 1.03 1.03 1.04 1.04 1.04 1.04 1.03 1.04 1.04 1.06 1.07 1.11 1.11 1.12 1.13 1.09 1.07 1.11 1.10 1.04 1.04  56.7 56.7 56.7 57.6 58.5 57.6  6.0 5.9 5.6 5.8 6.1 6.1  0.34 0.34 0.57 0.82 0.82 0.88  9.8 9.9 10.7 10.8 10.5 10.3  18 112 144 176 205 172  1.04 1.04 1.06 1.08 1.08 1.09  Chemical Flow  Total Flow  Effluent NOx  (l/d)  (l/d)  (mg/l)  202  Effluent Dilution Factor  Corrected Effluent NH4 (mg N/l)  MLE System #2  Date Nov 15/94 Nov 18/94 Nov 22/94 Nov 25/94 Nov 29/94 Dec 2/94 Dec 6/94 Dec 9/94 Dec 12/94 Dec 16/94 Dec 20/94 Dec 23/94 Dec 27/94 Dec 30/94 Jan 3/95 Jan 6/95 Jan 10/95 Jan 13/95 Jan 17/95 Jan 20/95 Jan 24/95 Jan 27/95 Jan 31/95 Feb 3/95 Feb 7/95 Feb 10/95 Feb 14/95 Feb 17/95 Feb 21/95 Feb 24/95 Feb 28/95 Mar 3/95 Mar 7/95  Day 130 133 137 140 144 147 151 154 157 161 165 168 172 175 179 182 186 189 193 196 200 203 207 210 214 217 221 224 228 231 235 238 242  Clarifier Recycle Flow (l/d) 57.6 58.5 58.5 57.6 58.5 58.5 58.5 58.5 58.5 73.8 73.8 76.5 75.6 74.7 74.7 74.7 73.8 73.8 73.8 73.8 73.8 73.8 73.8 72.9 72.9 72.9 75.6 74.7 73.8 73.8 73.8 73.8 73.8  Clarifier Recycle Ratio 5.9 5.9 6.1 6.0 6.1 6.4 6.3 6.4 6.3 7.9 7.9 8.1 8.1 7.9 7.7 7.9 7.6 8.1 8.1 8.1 7.8 8.1 7.8 7.2 8.7 8.0 8.1 8.2 7.9 8.5 7.6 7.9 7.8  Chemical Flow (l/d) 0.97 1.06 1.04 1.07 1.11 1.13 1.15 1.16 1.21 1.06 1.15 1.21 1.00 1.22 0.91 1.07 1.02 0.87 0.97 1.24 1.19 1.14 1.01 1.13 1.18 1.11 1.29 1.01 1.05 1.07 0.31 0.89 0.94  203  Total Flow (l/d) 10.8 10.9 10.7 10.7 10.8 10.3 10.5 10.3 10.6 10.4 10.5 10.7 10.4 10.7 10.6 10.5 10.8 10.0 10.1 10.3 10.6 10.2 10.5 11.2 9.5 10.3 10.7 10.2 10.4 9.7 10.0 10.2 10.4  Effluent NOx (mg/l) 127 118 90 89 128 126 127 130 105 95 86 114 99 106 60 75 69 60 96 268 140 122 142 149 129 137 147 143 148 219 94 97 99  Corrected Effluent Effluent Dilution NH4 Factor (mg N/l) 1.10 1 1.11 6 1.11 11 1.11 4 1.12 8 1.12 10 1.12 13 1.13 18 1.13 26 1.11 13 1.12 22 1.13 12 1.11 20 1.13 26 1.09 97 1.11 186 1.10 166 1.09 238 1.11 143 1.14 44 1.13 47 1.13 42 1.11 74 1.11 46 1.14 60 1.12 29 1.14 28 1.11 3 1.11 14 1.12 4 1.03 6 1.10 . 9 1.10 5  MLE System #2  Date Jul 12/94 Jul 14/94 Jul 15/94 Jul 18/94 Jul 20/94 Jul 22/94 Jul 25/94 Jul 27/94 Aug 1/94 Aug 3/94 Aug 5/94 Aug 8/94 Aug 10/94 Aug 12/94 Aug 15/94 Aug 17/94 Aug 19/94 Aug 22/94 Aug 24/94 Aug 26/94 Aug 29/94 Aug 31/94 Sep 2/94 Sep 6/94 Sep 9/94 Sep 12/94 Sep 14/94 Sep 16/94 Sep 19/94 Sep 21/94 Sep 23/94 Sep 26/94 Sep 28/94 Sep 30/94 Oct 3/94 Oct 7/94 Oct 11/94 Oct 14/94 Oct 17/94 Oct 19/94 Oct 21/94 Oct 23/94 Oct 25/94 Oct 28/94 Nov 1/94 Nov 4/94 Nov 8/94 Nov 11/94  Total Corrected Effluent Effluent Inorganic NOx Nitrogen Day (mg N/l) (mg N/l) 5 7 8 11 13 15 18 257 20 256 24 331 26 289 28 240 31 236 33 255 35 184 38 192 40 234 42 251 45 256 47 252 49 218 52 208 54 162 56 135 60 51 63 38 66 36 68 34 70 31 73 82 75 126 77 228 80 330 82 446 84 546 87 592 91 524 95 362 98 423 101 455 103 208 105 31 107 109 19 112 116 116 152 119 190 123 222 126 188  Total Inorganic Nitrogen Removal (%)  204  MLE System #2  Date Nov 15/94 Nov 18/94 Nov 22/94 Nov 25/94 Nov 29/94 Dec 2/94 Dec 6/94 Dec 9/94 Dec 12/94 Dec 16/94 Dec 20/94 Dec 23/94 Dec 27/94 Dec 30/94 Jan 3/95 Jan 6/95 Jan 10/95 Jan 13/95 Jan 17/95 Jan 20/95 Jan 24/95 Jan 27/95 Jan 31/95 Feb 3/95 Feb 7/95 Feb 10/95 Feb 14/95 Feb 17/95 Feb 21/95 Feb 24/95 Feb 28/95 Mar 3/95 Mar 7/95  Day 130 133 137 140 144 147 151 154 157 161 165 168 172 175 179 182 186 189 193 196 200 203 207 210 214 217 221 224 228 231 235 238 242  Total Total Inorganic Corrected Effluent Inorganic Nitrogen Effluent NOx Nitrogen Removal (mg N/l) (mg N/l) (%) 140 141 136 131 111 100 103 91 99 151 87 143 88 142 152 156 87 143 146 164 86 145 88 119 119 90 106 90 97 119 129 141 88 129 89 110 146 87 120 163 86 66 76 83 269 76 242 79 303 76 66 106 249 81 349 73 305 158 205 83 137 179 86 231 81 157 166 211 82 208 85 147 154 183 85 196 84 167 86 159 162 84 165 179 251 79 246 90 97 103 106 115 89 114 89 109  205  Bardenpho System Leachate (Influent) Data  Day Date Mar 10/95 3 Mar 13/95 6 8 Mar 15/95 Mar 17/95 10 Mar 20/95 13 Mar 22/95 15 17 Mar 24/95 Mar 27/95 20 Mar 30/95 23 Apr 3/95 27 Apr 5/95 29 Apr 7/95 31  NH4 (mg N/l) 181 172 171 168 149 123 135 103 124 154 156 159  NOx (mg N/l) 0.3 0.3 0.7 0.3 0.2 0.5 0.6 0.9 0.4 0.2 0.2 0.3  N02 (mg N/l) 0.0 0.0 0.0 0.1 0.1 0.2 0.2 0.1 0.1 0.1 0.1 0.1  206  0-P04 (mp P/l) 0.23 0.17 0.32 0.26 0.21 0.33 0.21 0.15 0.17 0.39 0.36 0.27  PH 7.4 7.4 7.5 7.5 7.5 7.6 7.5 7.4 7.4 7.5 7.7 7.6  Bardenpho System Leachate (Influent) Data  Akalinity Day (mg CaC03/l) Date Mar 10/95 3 1540 6 Mar 13/95 1460 Mar 15/95 8 Mar 17/95 10 Mar 20/95 13 Mar 22/95 15 960 Mar 24/95 17 Mar 27/95 20 1160 Mar 30/95 23 Apr 3/95 27 Apr 5/95 29 Apr 7/95 31  TSS (mg/l)  BOD5 (mg/l)  VSS (mg/l) 17  32  11 34  15  16  8  21  10 18  207  COD (mg/l) 306 321 311 261 244 207 188 188 234 234 253 256  Bardenpho System  Date Day 3 Mar 10/95 Mar 13/95 6 Mar 15/95 8 10 Mar 17/95 13 Mar 20/95 15 Mar 22/95 Mar 24/95 17 Mar 27/95 20 Mar 30/95 23 Apr 3/95 27 Apr 5/95 29 Apr 7/95 31  P04  P04  CH30H  CH30H  NH4CI  NaHC03  #1  #2  #1  #2  #1  #1  Feed Flow (ml/hr) 5.3 4.9 5.8 5.0 5.3 5.1 5.1 5.2 5.0 4.9 5.4 4.9  Feed Flow (ml/hr) 5.3 4.9 5.8 5.0 5.3 5.1 5.1 5.2 5.0 4.9 5.4 4.9  Feed Flow (ml/hr) 7.7 8.0 7.9 7.9 8.3 8.0 8.5 7.9 8.0 7.9 8.3 8.0  208  Feed Flow (ml/hr) 7.3 8.0 7.9 7.9 8.3 8.0 8.5 7.9 8.0 7.9 8.3 8.0  Feed Flow (ml/hr) 9.1 9.3 9.4 9.4 9.4 9.8 9.4 9.6 9.6 9.4 9.6 9.7  Feed Flow (ml/hr) 32.7 27.2 29.7 27.3 25.1 27.8 27.8 29.0 29.0 27.8 26.8 27.2  NaHC03 #2  Feed Flow (ml/hr) 0 0 0 0 0 0 0 0 0 0 0 0  Bardenpho System  Date Day Mar 10/95 3 Mar 13/95 6 Mar 15/95 8 Mar 17/95 10 Mar 20/95 13 Mar 22/95 15 Mar 24/95 17 20 Mar 27/95 Mar 30/95 23 Apr 3/95 27 Apr 5/95 29 31 Apr 7/95  Leachate (l/d) 8.9 9.1 9.1 9.1 8.9 9.1 9.1 9.1 9.1 8.9 9.0 8.9  Aerobic #1 Recycle (l/d) 36.9 36.9 36.9 36.9 36.0 36.9 36.9 36.9 36.9 36.0 36.0 36.0  Clarifier Recycle (l/d) 18.4 18.4 18.4 18.4 27.0 27.0 27.0 27.0 27.0 27.4 27.4 27.4  209  Post Flow (l/d) 27.0 24.8 25.0 27.7 36.6 37.2 36.6 36.6 36.0 38.4 39.6 39.6  Anoxic #1 Overflow (l/d) 64.7 64.9 65.0 64.9 72.5 73.5 73.6 73.5 73.5 72.8 73.0 72.8  Anoxic #2 Overflow (l/d) 27.3 25.1 25.3 28.0 36.9 37.5 36.9 36.9 36.3 38.7 39.9 39.9  Bardenpho System  Date Day Mar 10/95 3 Mar 13/95 .6 Mar 15/95 8 Mar 17/95 10 Mar 20/95 13 Mar 22/95 15 Mar 24/95 17 20 Mar 27/95 23 Mar 30/95 Apr 3/95 27 Apr 5/95 29 Apr 7/95 31  Aerobic #1 Aerobic #2 Aerobic #1 Overflow Overflow Wasting (l/d) (l/d) (l/d) 65.5 27.3 0.5 0.5 65.6 25.1 0.5 65.7 25.3 28.0 0.5 65.6 0.5 73.1 36.9 37.5 0.5 74.2 36.9 0.5 74.2 74.2 36.9 0.5 74.2 36.3 0.5 0.5 73.5 38.7 39.9 0.5 73.6 73.5 39.9 0.5  210  Anoxic #1 Anoxic #2 Aerobic #1 AHRT AHRT AHRT (hr) (hr) (hr) 1.85 4.40 3.66 3.66 1.85 4.78 4.74 3.65 1.85 3.66 1.85 4.28 1.66 3.25 3.29 3.20 3.23 1.63 3.23 1.63 3.25 3.23 1.63 3.25 3.23 1.63 3.30 3.10 3.27 1.65 1.64 3.01 3.26 3.27 1.65 3.01  Bardenpho System  Date Day Mar 10/95 3 Mar 13/95 6 Mar 15/95 8 Mar 17/95 10 Mar 20/95 13 Mar 22/95 15 Mar 24/95 17 Mar 27/95 20 Mar 30/95 23 Apr 3/95 27 Apr 5/95 29 Apr 7/95 31  Aerobic #2 AHRT (hr) 8.79 9.56 9.48 8.57 6.50 6.40 6.50 6.50 6.61 6.20 6.01 6.01  P04 #1,#2 Feed Cone (g P/I) 0.974 0.974 0.974 0.974 0.840 0.840 0.840 0.840 0.840 0.840 0.872' 0.872  Clarifier AHRT (hr) 3.52 3.82 3.79 3.43 2.60 2.56 2.60 2.60 2.64 2.48 2.40 2.41  211  CH30H #1 Feed Cone (ml/1) 65 100 100 90 90 90 80 80 80 85 85 85  CH30H #2 Feed Cone (ml/l) 50 80 80 70 90 90 80 80 80 85 85 85  Bardenpho System  Date Day 3 Mar 10/95 6 Mar 13/95 8 Mar 15/95 Mar 17/95 10 13 Mar 20/95 Mar 22/95 15 Mar 24/95 17 Mar 27/95 20 Mar 30/95 23 Apr 3/95 27 Apr 5/95 29 Apr 7/95 31  NH4CI Feed Cone (g NH4CL/I) 150 150 150 150 150 150 150 150 150 150 150 150  NaHC03 #1 Feed Cone (g/i) 80 80 80 80 80 80 80 80 80 80 80 80  0-P04 (g P/d) 0.126 0.116 0.138 0.119 0.109 0.106 0.105 0.106 0.102 0.102 0.116 0.105  212  Anoxic #1 Methanol COD Load (g COD/d) 14.26 22.80 22.52 20.26 21.29 20.52 19.38 18.01 18.24 19.14 20.11 19.38  Simulated Anoxic #2 Leachate Methanol Ammonia Con'c COD Load (g COD/d) (mg N/l) 10.40 1117 18.24 1108 1116 18.01 15.76 1113 21.29 1116 1109 20.52 1081 19.38 18.01 1070 18.24 1090 19.14 1121 1132 20.11 19.38 1155  Bardenpho System  Day Date 3 Mar 10/95 Mar 13/95 6 Mar 15/95 8 Mar 17/95 10 Mar 20/95 13 Mar 22/95 15 17 Mar 24/95 Mar 27/95 20 Mar 30/95 23 Apr 3/95 27 Apr 5/95 29 Apr 7/95 31  Anoxic #1 Anoxic #2 Anoxic #1 Anoxic #2 pH ORP ORP PH (mV) (mV) -188 -150 8.2 8.8 -267 8.3 8.9 -261 -218 8.4 8.9 -222 -236 8.3 9.0 -252 -255 -273 8.2 8.8 -228 8.3 8.9 -212 8.2 8.8 -276 -239 -227 -221 8.2 9.0 8.1 8.9 -240 -244 8.1 8.8 -230 -219 8.3 8.9 -226 -268 8.2 8.9 -209 -236  Ammonia NaHC03 Load (g N/d) g CaC03/d) 10.18 51.11 10.33 45.13 10.41 47.26 10.38 44.52 10.18 41.71 10.35 40.72 40.72 10.08 9.98 43.73 43.73 10.17 10.23 42.13 41.10 10.45 10.55 41.44  i"  213  Bardenpho System  Date Day Mar 10/95 3 Mar 13/95 6 Mar 15/95 8 Mar 17/95 10 Mar 20/95 13 Mar 22/95 15 17 Mar 24/95 Mar 27/95 20 Mar 30/95 23 Apr 3/95 27 Apr 5/95 29 Apr 7/95 31  Aerobic #1 Aerobic #2 Aerobic #1 Aerobic #2 Anoxic #1 Anoxic #2 Aerobic #1 DO. DO. pH pH NH4 NH4 NH4 (mg N/l) (mg N/l) (mg N/l) (mg/l) (mg/l) 3.9 4.6 7.6 8.1 142 15 11 24 29 7.9 165 7.4 3.0 2.1 7 11 147 7.5 8.2 3.8 4.2 10 13 8.0 153 4.2 7.5 3.6 156 19 29 7.4 7.8 3.5 2.2 23 141 17 7.5 7.9 4.0 3.2 20 146 16 7.4 7.8 3.9 2.9 10 14 8.1 118 3.8 7.5 3.8 9 13 7.9 125 4.1 4.4 7.3 17 20 7.8 145 4.3 2.8 7.3 4.3 2.7 7.5 8.0 144 17 23 3.8 3.7 7.4 8.0 137 14 18  214  Bardenpho System  Date Day Mar 10/95 3 6 Mar 13/95 Mar 15/95 8 10 Mar 17/95 Mar 20/95 13 Mar 22/95 15 Mar 24/95 17 20 Mar 27/95 Mar 30/95 23 Apr 3/95 27 29 Apr 5/95 Apr 7/95 31  Aerobic #2 NH4 (mg N/l) 3 0 0 0 0 0 0 0 0 0 0 0  Effluent Anoxic #1 Anoxic #2 Aerobic #1 Aerobic #2 NH4 NOx NOx NOx NOx (mg N/l) (mg N/l) (mg N/l) (mg N/l) (mg N/l) 3 89 92 250 82 20 0 129 0 1 164 14 2 0 12 0 147 16 0 0 0 106 11 0 0 15 1 115 0 1 14 1 131 0 0 155 17 4 2 0 148 17 5 3 0 148 17 3 3 0 0 1 150 15 0 2 118 18 0 4  215  Effluent NOx (mg N/l) 66 15 11 11 10 13 11 15 16 15 12 15  Bardenpho System  Date Day 3 Mar 10/95 6 Mar 13/95 Mar 15/95 8 10 Mar 17/95 13 Mar 20/95 Mar 22/95 15 Mar 24/95 17 20 Mar 27/95 23 Mar 30/95 Apr 3/95 27 Apr 5/95 29 31 Apr 7/95  Anoxic #1 Anoxic #2 Aerobic #1 Aerobic #2 N02 N02 N02 N02 (mg N/l) (mg N/l) (mg N/l) (mg N/l) 52 60 159 26 1 0 93 0 0 1 119 9 0 0 100 0 1 0 71 0 77 1 1 0 78 1 0 0 1 1 91 2 90 1 3 1 86 1 1 2 80 1 0 0 88 1 3 2  216  Effluent Anoxic #1 Anoxic #2 N02 0-P04 0-P04 (mg P/l) (mg N/l) (mg P/l) 18 5.1 3.5 1 5.6 3.6 0 4.9 3.1 0 5.5 3.5 0 6.2 4.3 1 6.6 4.5 4.7 0 6.8 1 6.6 4.0 0 6.7 4.0 3.9 0 4.2 0 7.6 4.0 6.7 3.8 0  Bardenpho System  Date Day Mar 10/95 3 6 Mar 13/95 Mar 15/95 8 Mar 17/95 10 Mar 20/95 13 Mar 22/95 15 Mar 24/95 17 Mar 27/95 20 Mar 30/95 23 Apr 3/95 27 Apr 5/95 29 Apr 7/95 31  Aerobic #1 Aerobic #2 Anoxic #1 Anoxic #2 Aerobic #1 Aerobic #2 TSS TSS TSS 0-P04 0-P04 TSS (mg/l) (mg/l) (mg/l) (mg/l) (mg P/l) (mg P/l) 5.1 4.9 9004 8380 6420 6708 5648 7444 5640 6.3 7664 5.4 6456 5460 4.9 8268 7372 5.4 6092 6464 5.5 9200 8276 5.5 7756 6096 6340 9036 5.7 6.0 5820 12040 7400 6112 6.4 6.7 6260 7620 6232 6.5 10396 6.2 7428 6428 12456 8368 6.5 6.6 8780 7972 7380 7.2 11548 7.1 7188 7500 7.0 11284 8876 6.7 6936 6612 7.1 11392 7768 6.9 7192 11572 9488 8440 6.6 6.8  217  Effluent TSS (mg/l) 26 27 61 27 92 14 25 11 13 14 19 18  Bardenpho System  Day Date 10/95 3 13/95 6 8 15/95 17/95 10 Mar 20/95 13 Mar 22/95 15 Mar 24/95 17 Mar 27/95 20 Mar 30/95 23 Apr 3/95 27 Apr 5/95 29 Apr 7/95 31  Mar Mar Mar Mar  Anoxic #1 Anoxic #2 Aerobic #1 Aerobic #2 VSS VSS VSS VSS (mg/l) (mg/l) (mg/l) (mg/l) 7896 7276 5608 5852 4900 4904 6672 6432 7148 6248 4676 5528 7084 5252 5560 7956 5472 7808 6636 5228 5284 5008 10448 6352 5404 8992 6520 5368 5536 10748 7184 6380 7496 6816 6300 9932 9748 7564 6440 6176 9836 6664 5944 5656 9972 8080 7264 6152  218  Effluent Anoxic #1 Anoxic #2 BOD5 BOD5 VSS (mg/l) (mg/l) (mg/l) 24 25 51 108 24 37 83 13 23 11 12 12 18 19 80 17  Bardenpho System  Date Mar 10/95 Mar 13/95 Mar 15/95 Mar 17/95 Mar 20/95 Mar 22/95 Mar 24/95 Mar 27/95 Mar 30/95 Apr 3/95 Apr 5/95 Apr 7/95  Aerobic #1 Aerobic #2 BOD5 BOD5 Day (mg/l) (mg/l) 3 6 8 7 10 25 13 15 17 20 23 27 12 10 29 31  Anoxic #1 Anoxic #2 Aerobic #1 Aerobic #2 COD COD COD COD (mg/l) (mg/l) (mg/l) (mg/l) 203 149 70 292 370 306 351 548 147 278 284 327 151 228 327 360 8 216 244 311 377 199 284 284 361 380 217 246 303 284 146 246 246 253 291 174 289 234 291 329 142 185 234 5 370 292 159 273 288 325  Effluent BOD5 (mg/l)  219  Bardenpho System  Date Day Mar 10/95 3 6 Mar 13/95 Mar 15/95 8 Mar 17/95 10 Mar 20/95 13 Mar 22/95 15 Mar 24/95 17 Mar 27/95 20 Mar 30/95 23 Apr 3/95 27 Apr 5/95 29 Apr 7/95 31  Effluent COD (mg/l) 255 366 244 261 261 284 246 246 234 253 253 238  Anoxic #1 Anoxic #2 Aerobic #1 Aerobic #2 Effluent VSS/TSS VSS/TSS VSS/TSS VSS/TSS VSS/TSS 0.88 0.87 0.87 0.87 0.92 0.87 0.87 0.93 0.87 0.86 0.86 0.84 0.86 0.85 0.86 0.86 0.86 0.89 0.86 0.86 0.86 0.86 0.86 0.90 0.86 0.93 0.87 0.86 0.86 0.86 0.86 0.86 0.86 0.92 0.86 0.86 0.86 0.86 1.00 0.86 0.92 0.86 0.85 0.85 0.85 0.86 0.85 0.86 0.86 0.86 0.86 0.86 0.86 0.95 0.86 0.94 0.86 0.85 0.86 0.86  220  Bardenpho System  Anoxic #1 Anoxic #2 Aerobic #1 Aerobic #2 Effluent Day N02/NOx N02/NOx N02/NOx N02/NOx N02/NOx Date Mar 10/95 3 0.58 0.65 0.64 0.32 0.27 Mar 13/95 6 0.00 0.00 0.72 0.05 0.07 Mar 15/95 8 0.75 0.50 0.73 0.00 0.00 Mar 17/95 10 0.00 0.00 0.68 0.00 0.00 0.00 0.67 0.09 0.00 Mar 20/95 13 0.00 Mar 22/95 15 1.00 0.00 0.67 0.07 0.08 Mar 24/95 17 0.00 0.00 0.60 0.07 0.00 Mar 27/95 20 0.50 0.50 0.59 0.06 0.07 Mar 30/95 23 0.60 0.33 0.61 0.06 0.00 Apr 3/95 27 0.33 0.67 0.58 0.06 0.00 Apr 5/95 29 0.00 0.00 0.53 0.07 0.00 Apr 7/95 31 0.75 1.00 0.75 0.06 0.00  221  Anoxic #1 NH4 Removal Rate (mg N/d) 1452 682 1269 928 -78 829 83 1819 1459 385 769 1221  Bardenpho System  Day Date Mar 10/95 3 Mar 13/95 6 Mar 15/95 8 Mar 17/95 10 Mar 20/95 13 Mar 22/95 15 Mar 24/95 17 Mar 27/95 20 Mar 30/95 23 27 Apr 3/95 Apr 5/95 29 Apr 7/95 31  Anoxic #2 Aerobic #1 Aerobic #2 % % % % NH4 NH4 NH4 Removal Removal Removal Anoxic #1 Anoxic #2 Aerobic #1 Aerobic #2 NH4 NH4 NH4 NH4 Rate Rate Rate (mg N/d) (mg N/d) (mg N/d) Removal Removal Removal Removal -113 8471 328 13.6 -37.9 92.2 80.0 100.0 16.2 82.2 603 6.0 117 8812 100.0 35.5 92.4 177 98 8826 11.7 91.4 100.0 8.5 22.2 9082 280 80 81.3 100.0 -0.7 33.9 360 9184 702 83.5 100.0 7.4 25.5 218 8664 638 100.0 19.3 86.2 9254 591 0.8 141 88.0 100.0 28.0 143 7639 369 17.3 100.0 89.5 327 13.7 30.2 141 8228 86.1 100.0 3.5 14.3 110 9091 658 100.0 6.8 25.5 83.9 232 8813 679 100.0 21.6 86.7 154 8656 559 10.9  222  Bardenpho System  %  Date Day Mar 10/95 3 Mar 13/95 6 Mar 15/95 8 Mar 17/95 10 Mar 20/95 13 Mar 22/95 15 Mar 24/95 17 Mar 27/95 20 Mar 30/95 23 Apr 3/95 27 Apr 5/95 29 Apr 7/95 31  System NH4 Removal 100 100 100 100 100 100 100 100 100 100 100 100  Anoxic #1 Anoxic #2 Anoxic #1 Anoxic #2 Denitr Denitr NOx NOx Load Load Rate Rate (mg N/d) (mg N/d) (mg N/d) (mg N/d) 10442 6750 4681 4238 3199 5039 3199 5039 6260 4100 5481 4049 5629 4072 5629 4072 4088 3880 4088 3880 4240 4599 4278 4526 5136 4795 5136 4758 6133 5673 5839 5599 5897 5529 5219 5328 5567 5741 5683 5522 5731 5940 5731 5900 4662 4673 4370 4593  223  Anoxic #1 Anoxic #2 Specific Specific Denitr Denitr Rate Rate (mg N/d/ (mg N/d/ mg VSS) mg VSS) 0.119 0.116 0.151 0.099 0.153 0.130 0.115 0.142 0.105 0.117 0.087 0.134 0.114 0.146 0.109 0.156 0.111 0.139 0.113 0.147 0.117 0.177 0.088 0.114  Bardenpho System  %  Date Day Mar 10/95 3 Mar 13/95 6 Mar 15/95 8 Mar 17/95 10 Mar 20/95 13 Mar 22/95 15 Mar 24/95 17 Mar 27/95 20 Mar 30/95 23 Apr 3/95 27 Apr 5/95 29 Apr 7/95 31  %  Anoxic #1 Anoxic #2 Denitr Denitr 44.8 62.8 100.0 100.0 87.5 98.8 100.0 100.0 100.0 100.0 98.4 99.1 100.0 99.2 95.2 98.7 93.8 98.0 96.2 98.0 100.0 99.3 93.7 98.3  Aerobic #1 Aerobic #2 Nitr Nitr Rate Rate (mg N/d) (mg N/d) 10618 -273 8461 502 9990 304 9642 448 7744 406 8461 525 9723 480 11213 554 10620 508 10660 542 11040 559 8381 639  224  Aerobic #1 Aerobic #2 Specific Specific Nitr Nitr Rate Rate % (mg N/d/ (mg N/d/ Aerobic #1 Nitr mg VSS) mg VSS) 0.189 -0.005 115.5 0.173 0.010 79.0 0.214 0.005 104.6 0.184 0.008 97.0 0.148 0.007 68.5 0.160 0.010 81.6 0.181 0.009 90.5 0.176 0.010 129.2 0.156 0.008 115.5 0.166 0.009 100.9 0.186 0.010 105.1 0.115 0.010 84.0  Bardenpho System  %  Date Day Mar 10/95 3 Mar 13/95 6 Mar 15/95 8 Mar 17/95 10 Mar 20/95 13 Mar 22/95 15 Mar 24/95 17 Mar 27/95 20 Mar 30/95 23 Apr 3/95 27 Apr 5/95 29 Apr 7/95 31  Aerobic #2 Nitr -66.7 83.3 171.4 160.0 57.9 82.4 81.3 150.0 155.6 82.4 82.4 114.3  Anoxic #1 Anoxic #2 COD:NOx COD:NOx Entering Entering (mg COD/ (mg COD/ mg N) mg N) 1.37 1.54 4.52 5.70 3.60 4.39 3.60 3.87 5.21 5.49 4.46 4.80 3.77 4.04 2.94 3.18 3.09 3.42 3.33 3.37 3.51 3.38 4.16 4.15  225  Anoxic #1 COD:NOx Removed (mg COD/ mg N) 3.05 * 4.52 4.11 3.60 5.21 4.53 3.77 3.09 3.30 3.47 3.51 4.43  Anoxic #2 Aerobic #1 Aerobic #1 COD:NOx Alk:NH4 Alk:NH4 Added Nitrified Removed (mg COD/ (g CaC03/ (g CaC03/ mg N) gN) gN) 2.45 5.02 4.81 5.70 4.37 5.33 4.45 4.54 4.73 3.87 4.29 4.62 5.49 4.10 5.39 4.84 3.93 4.81 4.07 4.04 4.19 3.22 4.38 3.90 3.49 4.30 4.12 3.44 •4.12 3.95 3.41 3.93 3.72 4.22 3.93 4.94  Bardenpho System  Day Date Mar 10/95 3 6 Mar 13/95 Mar 15/95 8 Mar 17/95 10 13 Mar 20/95 15 Mar 22/95 17 Mar 24/95 Mar 27/95 20 Mar 30/95 23 Apr 3/95 27 Apr 5/95 29 Apr 7/95 31  Aerobic #1 SRT (days) 20 20 20 20 20 20 20 20 20 20 20 20  Simulated Aerobic #1 Leachate Recycle Aerobic #1 Flow Flow Recycle Ratio (l/d) (l/d) 9.1 36.9 4.0 9.3 36.9 4.0 4.0 9.3 36.9 4.0 9.3 36.9 9.1 36.0 3.9 9.3 36.9 4.0 4.0 9.3 36.9 9.3 36.9 4.0 9.3 36.9 4.0 9.1 36.0 3.9 9.2 36.0 3.9 9.1 36.0 3.9  System SRT (days) 72.8 71.8 73.1 73.9 60.1 76.3 72.9 71.7 71.0 72.6 70.9 66.4  226  Clarifier Recycle Flow (l/d) 18.4 18.4 18.4 18.4 27.0 27.0 27.0 27.0 27.0 27.4 27.4 27.4  Bardenpho System  Date Day Mar 10/95 3 6 Mar 13/95 Mar 15/95 8 Mar 17/95 10 Mar 20/95 13 Mar 22/95 15 Mar 24/95 17 Mar 27/95 20 Mar 30/95 23 Apr 3/95 27 Apr 5/95 29 Apr 7/95 31  Clarifier Recycle Ratio 2.0 2.0 2.0 2.0 3.0 2.9 2.9 2.9 2.9 3.0 3.0 3.0  Chemical Flow (l/d) 1.62 1.50 1.60 1.50 1.48 1.53 1.55 1.56 1.55 1.51 1.53 1.50  Total Flow  Effluent NOx  (l/d) 10.7 10.8 10.9 10.8 10.6 10.9 10.9 10.9 10.9 ' 10.6 10.8 10.6  227  (mg/l) 66 15 11 11 10 13 11 15 16 15 12 15  Effluent Dilution Factor 1.18 1.16 1.17 1.16 1.16 1.16 1.17 1.17 1.17 1.17 1.17 1.16  Total Corrected Inorganic Effluent Nitrogen NOx Removal (mg/l) (%) 78 93 17 98 13 99 13 99 12 99 15 99 13 99 18 98 19 98 98 17 14 99 17 98  APPENDIX C STATISTICAL ANALYSES  228  MLE Systems  Day  Anoxic 1 AHRT (hr)  Anoxic 2 Aerobic 1 Aerobic 2 AHRT AHRT AHRT (hr) (hr) (hr)  1.44 1.44 1.39 1.41 1.42 1.42 1.42 1.43 1.44 1.44 1.44 1.43  3.16 3.19 3.19 3.19 3.19 3.19 3.19 3.19 3.20 3.20 3.19 3.19  2.85 2.85  182 186 189 193 196 200  1.59 1.61 1.61 1.61 1.61 1.61 1.61 1.61 1.61 1.61 1.61 1.61  203 207 210  1.59 1.59 1.59  1.44 1.43 1.44  2.86 2.85 2.85  214 217 221 224 228 231 235 238 242  1.60 1.60 1.62 1.60 1.60 1.60 1.62 1.62 1.62  1.47 1.46 1.41 1.42 1.44 1.45 1.43 1.44 1.43  3.15 3.15 3.15 3.16 3.17 3.20 3.17 3.17 3.16 3.20 3.21 3.21  161 165 168 172 175  179  2.75 2.79 2.81 2.81 2.82 2.84 2.86 2.86 2.85 2.84  2.91 2.89 2.78 2.83 2.85 2.87 2.86 2.85 2.85  229  Clarifier 1 Clarifier 2 AHRT AHRT (hr) (hr)  1.26 1.28 1.28 1.28 1.28 1.28 1.28 1.28 1.28 1.28 1.27 1.28  1.14 1.14 1.10 1.12 1.12 1.13 1.13 1.13 1.15 1.14 1.14 1.14  1.26 1.26 1.26 1.27 1.27 1.28 1.27 1.27 1.27 1.28 1.28 1.28  1.14 1.14 1.14 1.16 1.15 1.11 1.13 1.14 1.15 1.15 1.14 1.14  M L E Systems  t-Test: Paired Two Sample for Means Anoxic A H R T ' s  Variable 1 Variable 2 Mean Variance Observatio Pearson C< Hypothesiz df tStat P(T<=t) on. t Critical or P(T<=t) twc t Critical tw  1.60625 9.4E-05 24 -0.36817 0 23 38.29635 1.22E-22 1.71387 2.45E-22 2.068655  1.4325 0.00028 24  t-Test: Paired Two Sample for Means Aerobic A H R T ' s  Variable 1Variable 2 Mean Variance Observatio Pearson C< Hypothesiz df tStat P(T<=t) o n t Critical or P(T<=t) twc  3.182083 0.000365 24 -0.35358 0 23 37.27586 2.26E-22 1.71387 4.52E-22  2.840833 0.001182 24  t Critical tw 2.068655  t-Test: Paired Two Sample for Means Clarifier A H R T ' s  Variable 1Variable 2 Mean Variance Observatio Pearson C< Hypothesiz df tStat P(T<=t) o n t Critical or P(T<=t) twc t Critical tw  1.274167 6.01 E-05 24 -0.34381 0 23 38.19845 1.3E-22 1.71387 2.6E-22 2.068655  1.13625 0.000181 24  230  f  MLE Systems  Day  161 165 168 172 175 179 182 186 189 193. 196 200 203 207 210 214 217 221 224 228 231 235 238 242  System 1 System 2 Ammonia Ammonia Load Load (g N/d) (g N/d) 11.16 11.40 11.62 11.19 10.92 11.35 10.56 11.72 11.29 11.70 11.64 11.37 11.31 11.18 11.44 11.66 10.86 11.35 10.77 10.47 10.11 9.59 9.46 9.55  10.97 11.49 11.59 11.38 10.85 11.13 10.41 11.50 11.38 11.83 11.65 11.35 11.24 11.28 11.84 11.41 11.26 11.38 10.48 10.69 10.22 9.62 9.45 9.94  t-Test: Paired Two Sample for Means Ammonia Loads Variable 1Variable 2 Mean 10.98625 11.01417 Variance 0.480477 0.450938 Observatio 24 24 Pearson Ct 0.958088 Hypothesiz 0 df 23 tStat -0.68825 P(T<=t) on 0.249091 t Critical or 1.71387 P(T<=t) twc 0.498182 t Critical tw 2.068655  MLE Systems  Day  207 210 214 217 221 224 228 231 235 238 242  System 1 Aerobic Nitr Rate (mg N/d) 11342 12031 13959 10912 13184 10306 13643 13682 7055 7859 8012  System 2 Aerobic Nitr Rate (mg N/d) 11798 12951 11132 11894 14146 12317 13151 14672 7965 8580 8766  t-Test: Paired Two Sample for Means MLE Aerobic Nitrification Rates Variable 1Variable 2 Mean 11089.55 11579.27 Variance 6364226 5136931 Observatio 11 11 Pearson C< 0.870369 Hypothesiz 0 df 10 tStat -1.30544 P(T<=t) on. 0.110489 t Critical or 1.812462 P(T<=t) twc 0.220979 t Critical tw 2.228139  232  MLE Systems  Day  203 207 210 214 217 221 224 228 235 238 242  System 1 System 2 Total Total System 1 System 1 System 2 Effluent Effluent Anoxic Ammonia Ammonia Inorganic Inorganic NOx Load Load Nitrogen Nitrogen Load (g N/d) (g N/d) (mg N/l) (mg N/l) (g N/d) 11.31 11.18 11.44 11.66 10.86 11.35 10.77 10.47 9.59 9.46 9.55  11.24 11.28 11.84 11.41 11.26 11.38 10.48 10.69 9.62 9.45 9.94  198 216 233 225 213 261 175 191 119 144 135  179 231 211 208 183 196 162 179 103 115 114  10252 9791 10517 12156 9463 11731 9004 11830 6094 6871 7000  System 2 Anoxic NOx Load (g N/d) 9670 10408 11304 9916 10426 12477 10909 11664 7014 7530 7751  t-Test: Paired Two Sample for Means Ammonia Loadings Variable 1 Variable 2 Mean 10.69455 10.78091 Variance 0.666947 0.649069 Observatio 11 11 Pearson Ci 0.954355 Hypothesiz 0 df 10 t Stat -1.16757 P(T<=t) on> 0.135033 t Critical or 1.812462 P(T<=t) twc 0.270067 t Critical tw 2.228139 t-Test: Paired Two Sample for Means Total Effluent Inorganic Nitrogen Variable 1 Variable 2 Mean 191.8182 171 Variance 1975.564 1855.6 Observatio 11 11 Pearson C< 0.907323 Hypothesiz 0 df 10 tStat 3.655517 P(T<=t) on. 0.002211 t Critical or 1.812462 P(T<=t) twc 0.004422 t Critical tw 2.228139  t-Test: Paired Two Sample for Means Anoxic NOx Loads Variable 1 Variable 2 Mean 9519 9915.364 Variance 4415096 3189132 Observatio 11 11 Pearson Ci 0.858508 Hypothesiz 0 df 10 t Stat -1.21986 P(T<=t) on. 0.125253 t Critical or 1.812462 P(T<=t) twc 0.250505 t Critical tw 2.228139  233  Bardenpho System Anoxic #1 Anoxic #2 Anoxic #1 Anoxic #2 NOx Load NOx Load Denit Rate Denit Rate (mg N/d) (mg N/d) (mg N/d) (mg N/d) Day 13 15 17 20 23 27 29 31  4088 4599 5136 6133 5987 5741 5731 4662  3880 4278 4795 5673 5328 5683 5940 4673  t-Test: Paired Two Sample for Means Bardenpho Anoxic NOx Loads Variable 1 Variable 2 Mean 5259.625 5031.25 Variance 561049.1 546775.4 Observatio 8 8 Pearson C< 0.93065 Hypothesiz 0 df 7 tStat 2.329128 P(T<=t) om 0.026341 t Critical or 1.894578 P(T<=t) twc 0.052682 t Critical tw 2.364623  4088 4526 5136 5839 • 5529 5522 5731 4370  3880 4240 4758 5599 5219 5567 5900 4593  t-Test: Paired Two Sample for Means Bardenpho Anoxic Denit Rates Variable 1 Variable 2 Mean 5092.625 4969.5 Variance 456255.4 512431.7 Observatio 8 8 Pearson Ci 0.94545 Hypothesiz 0 df 7 tStat 1.493344 P(T<=t) on. 0.089493 t Critical or 1.894578 P(T<=t) twc 0.178987 t Critical tw 2.364623  234  

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