Method and apparatus for nutrient removal using carbon source addition

Abstract

The present disclosure relates to nitrogen removal with carbon source addition, including wastewater treatment. Denitrification reactions can be terminated at the intermediate nitrite product that proceeds to anammox reactions. Nitrogen is removed by using electron donors including but not limited to acetate or glycerol in specific zones. The electron donors can be used to convert nitrate to nitrite by suitable feedings alone or in combination, anoxic SRT and / or maintenance of acetate residuals. Also presented are tests for anammox reactions followed by feeding nitrite and ammonia. Anammox can be selectively retained on media or other physical methods can be used. The overall goal of the present disclosure is to minimize the use of electron donors by maximizing denitrification and anammox reactions. Test results are provided for selective retention of anammox on biofilms, granular or suspended growth systems or nitrate residual control.

Description

[0001] This application is a divisional application of the patent application with the application number 201780053630.7, filed on June 22, 2017, and the title "Method and apparatus for nutrient removal using carbon source addition".

[0002] Cross Reference to Related Applications

[0003] This application claims priority to U.S. Provisional Patent Application 62 / 359,950, filed July 8, 2016. The entire disclosure of U.S. Provisional Patent 62 / 359,950 is incorporated herein by reference. TECHNICAL FIELD

[0004] The general field of the present disclosure relates to apparatuses generally in the wastewater treatment environment with respect to removal of nutrients by addition of electron donors. More specifically, such nutrient removal includes removal or partial removal of molecules including but not limited to nitrogen, nitrate, nitrite or other nitrogen compounds (denitrification or de-nitrification or de-nitrification or anammox). The methods and apparatuses of the present disclosure relate to removal of nutrients by controlled addition of external electron donor sources including but not limited to acetate or glycerol in specific zones, obtaining nitrate residuals by minimizing chemical oxygen demand or COD, or converting nitrate to a predetermined concentration to maintain a desired concentration of nutrients. BACKGROUND

[0005] The present disclosure relates to denitrification reactions in wastewater treatment processes by use of electron donors. Electron donors are required in wastewater treatment processes to achieve denitrification reactions. Electron donors can come from organic carbon or inorganic compounds. Many different types of organic sources can be used in practice including but not limited to alcohols such as glycerol, methanol, ethanol; volatile fatty acids such as acetate; carbohydrates including but not limited to sugars, starches or cellulose; wastewater carbon from industrial waste or production byproducts, methane, ethylene glycol, aldehydes or ketones. Inorganic sources include but are not limited to ammonia, sulfides and ferrous ions. The present disclosure seeks to use electron donors based on the type of organic matter used and their imposed solids retention time limitations and electron donor limitation conditions for partial or complete denitrification.

[0006] The present disclosure includes a modified application targeting the removal of nitrate or combined removal of ammonium and nitrate. Unlike prior art involving such as nitrification reactors (WO2006022539 Al), partial nitritation systems (CN105923774 (A, Chinese patent nr 14, 27, 15), anaerobic ammonia oxidation systems (Chinese nr 22, 23) and other aerobic steps (Chinese patent nr 12), the present disclosure does not involve these pre-treatment steps prior to partial denitrification reactions. Additionally, unlike prior art applications applying a two-stage approach (Chinese patent nr 2, 22, 20), when the present disclosure is combined with anaerobic ammonia oxidation bacteria, an electron donor is added to the anaerobic ammonia oxidation reactor to achieve partial denitrification reactions and anaerobic ammonia oxidation reactions in one sludge system.

[0007] According to preferred embodiments of the present disclosure, effective selection of partial denitrification reactions (denitrification) can be achieved by precisely controlling / restricting the addition of organic carbon or additional electron donor and / or maintaining nitrate residuals and / or maintaining restricted solids retention time. Anaerobic ammonia oxidation reactions can be maximized or facilitated by maintaining ammonium residuals concentrations to minimize diffusion restrictions. SUMMARY

[0008] In the present disclosure, based on the combined or separate provision of solids retention time restrictions, electron donor restrictions, excess residual nitrate or excess residual ammonia conditions, we propose the use of electron donors for denitrogenating organisms to partially denitrify. In some embodiments of the present disclosure, the denitrogenating organisms can be special organisms that can only partially denitrify from nitrate or nitrite. In additional embodiments, the denitrogenating organisms are more general organisms that use the complete step of denitrification reaction but can denitrify nitrate (convert nitrate to nitrite) at most under controllable conditions. In some such embodiments, the denitrogenating organisms can be retained using support materials such as synthetic carriers, encapsulation (in pure or mixed media), sand, anthracite, wood chips, stones or any other suitable media.

[0009] In other such embodiments, the denitrogenating organisms can be retained in biofilm, media, stone, coagulants or granular form using physical selectors such as screens, cyclones, airlift reactors, magnetic separators or other specific gravity determination, floatation, membrane or filtration devices. In particular embodiments, using electron donor restrictions, the anaerobic ammonia oxidation reaction (in the same reactor or in a separate reactor) can be used to remove nitrite using ammonia as an electron donor, accompanied by the use of a restricted electron donor that reduces nitrate or nitrite. In additional other embodiments, sensors of oxidized nitrogen can be used to calibrate the stoichiometry for external carbon source dosing. When a single reactor is used for both denitrification steps (from nitrate to nitrite and from nitrite to nitrogen gas), to ensure that the anaerobic ammonia oxidation reaction dominates the reduction of nitrite, a small amount of residual ammonia in the wastewater is preferred.

[0010] In other embodiments of the disclosure, anaerobic ammonia oxidation organisms can be enriched to the reactor when a denitrification reaction is being performed. Bioaugmentation can occur continuously or in parallel from a side stream or stream to the reactor. Anaerobic ammonia oxidation organisms can also be bioaugmented from this reactor to other reactors if desired in other embodiments. Anaerobic ammonia oxidation organisms can be collected and subsequently transferred to other processes to perform anaerobic ammonia oxidation reactions. Such reactors can include processes including, but not limited to, any of a solid film, granular or or suspended growth biological process. In such particular embodiments, ammonia can be delivered to the reaction step as a residual from a previous reaction or as a by-pass stream from an upflow or trickling process. In some such embodiments, anaerobic ammonia oxidation organisms can be retained using a support including, but not limited to, a synthetic carrier, sand, hard coal, wood chips, stone, a biofilm or encapsulated pure or mixed media or any other suitable media.

[0011] In other embodiments, anaerobic ammonia oxidation organisms can be retained using physical selectors including, but not limited to, screens, cyclones and airlift reactors, magnetic separators or other specific gravity, floatation and filtration devices. In particular embodiments, the reactor or reaction step can be a dedicated anoxic zone or present in a biological nutrient removal process or in the area of an overall or separate modification step. In such particular embodiments, oxidized nitrogen streams can be recycled to the anoxic zone to provide an electron acceptor. In particular embodiments, bioaugmentation with a defined amount of denitrifying organisms can be included to achieve denitrification. In still other embodiments, anaerobic ammonia oxidation reactions can occur in anoxic biofilms in an aerated zone by limiting oxygen diffusion within the biofilm.

[0012] Accordingly, the disclosure allows for the electron donor for denitrifying organisms to be partially denitrified (e.g., denitrified) based on nitrate residual and the required average nitrate residual can be adjusted up or down based on the solids retention time. The disclosure relates to the use of general or specific denitrifying organisms, additions including, but not limited to, anaerobic ammonia oxidation bioaugmentation of denitrification reactors achieved by using supports or physical selectors or anaerobic ammonia oxidation organism retention in anoxic biofilms in an aerated zone. Denitrifying organisms can also be bioaugmented if desired. Other reactions not explicitly mentioned or described herein also exist within the spirit of the disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0013] The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate several embodiments of the present disclosure and, together with the description, serve to explain the principles of the disclosure; in which:

[0014] Figure 1 Nitrogen reactions managed in accordance with the disclosure are described.

[0015] Figure 2a is a plot of the percentage (%) of partial denitrification reaction versus the ratio of maximum possible AnAOB rate to observed nitrate rate.

[0016] Figure 2 b is a plot of total N removal rate (mg-N / g VSS / d) versus the ratio of maximum possible AnAOB rate to observed nitrate rate.

[0017] Figure 3 Population control within the microbial mass or biological or synthetic structures dependent on availability of electron donor and degree of competition between de-nitrosation, denitrification and Anammox organisms is described.

[0018] Figure 4 is a detailed schematic of the pilot application where the process incorporates a biological nutrient removal system as an anoxic zone where Anammox is selectively retained using a 212 um aperture screen.

[0019] Figure 5 is a plot of influent and effluent levels of a partial denitrification reaction system over time with COD controlled to maintain nitrate residuals at 6-7 mg NO3-N / L.

[0020] Figure 6 Concentration (Al) and rate (A2) curves of nitrate and nitrite for 3 doses of acetate-COD / NOx in the absence of AnAOB are shown.

[0021] Figure 7 Concentration (Cl) and rate (C2) curves of nitrate and nitrite for 10 doses of acetate-COD / NOx in the absence of AnAOB are shown.

[0022] Figure 8 Concentration (El) and rate (E2) curves of nitrate and nitrite for 3 doses of acetate-COD / NOx in the presence of AnAOB (50% MLSS) are shown. COD was added at the same rate of 3 every 60 minutes.

[0023] Figure 9 Anoxic zone of the main stream pilot is shown where acetate was added at a COD / NOx of 3 every 20 minutes and COD / N of 0 (A), 3 (B) and 12 (C) every 60 minutes. The partial denitrification reaction potential in the cell was shown in panel D every 60 minutes relative to NO3 residuals.

[0024] Figure 10 A represents the proposed apparatus / process application selection as a separate step where the application includes selective Anammox retention (S / L separation) and addition of energy donor as a separate stream (1.1) or to the wastewater substrate (1.2) for de-nitrosation and Anammox in a one-step-sludge system.

[0025] Figure 10 B represents the proposed apparatus / process as an application choice for a separate step, where the application of denitrification and anaerobic ammonia oxidation in a two-step-sludge system includes selective anoxic ammonia oxidation retention control (S / L separation) and addition of energy donor as a separate stream (1.1) or to the wastewater substrate (1.2).

[0026] Figure 11 A2 represents the proposed apparatus / process as an application choice for a post-treatment step of a biological nutrient removal process, where the application of denitrification and anaerobic ammonia oxidation in a one-step-sludge system includes selective anoxic ammonia oxidation retention (S / L separation) and addition of energy donor as a separate stream.

[0027] Figure 11 B2 represents the proposed apparatus / process as an application choice for a post-treatment step of a biological nutrient removal process, where the application of denitrification and anaerobic ammonia oxidation in a two-step-sludge system includes selective anoxic ammonia oxidation retention control (S / L separation) and addition of energy donor as a separate stream.

[0028] Figure 12 A represents the apparatus / process integrated as a one-step denitrification / anaerobic ammonia oxidation step as an application choice for a separate step, including as selective anoxic ammonia oxidation retention (S / L separation) within a biological nutrient removal system as a dedicated zone for addition of external carbon source (3.1) or first zone with NOx return stream and energy donor from wastewater substrate (3.2).

[0029] Figure 12 B represents the apparatus / process integrated as a one-step denitrification / anaerobic ammonia oxidation step as an application choice for a separate step, including as selective anoxic ammonia oxidation retention time control (S / L separation) within a biological nutrient removal system as a dedicated zone for addition of external carbon source (3.1) or first zone with NOx return stream and energy donor from wastewater substrate (3.2).

[0030] Figure 13 is a schematic diagram showing control and operation of embodiments of the present disclosure.

[0031] Figures 14-16 is Figure 13 a flowchart of the control algorithm of the process shown in DETAILED DESCRIPTION

[0032] Some preferred embodiments of the present disclosure are shown in the accompanying drawings. Figure 1Nitrogen reactions are shown in the preferred embodiments of the present disclosure. Carbon source addition controls the reduction of nitrate to nitrite after the anammox bacteria have completed the oxidation of ammonium from nitrite. Denitrification is preferably the reduction of nitrate to nitrite, but denitritation refers to the reduction of nitrite. In the present disclosure, denitritation is preferably minimized.

[0033] Maximization of Reaction 1 (nitrate to nitrite) and Reaction 2 (ammonium + nitrite to nitrogen gas) is achieved by optimizing electron donor addition, nitrate residual, ammonium residual, and / or sludge retention time (SRT). Reactions 3 (nitrite to nitrogen gas) and 4 (aerobic oxidation of ammonium to nitrite or nitrate) are managed to meet wastewater treatment requirements and / or nitrite availability in the system.

[0034] The balance between denitrification, denitritation, and anammox was investigated based on a series of batch experiments using a mixture of anammox sludge and denitrifying sludge with ammonium (5 mg N / L) and nitrate (10 mg N / L) addition, different energy donors (acetate, methanol, ethanol, and glycerol), and different COD / N ratios (0-2) to evaluate the source of energy donor and the rate of feed in a non-adapted sludge. None of the above factors alone is identified as a key parameter for denitrification selection. However, from all the carbon sources tested, acetate showed the highest potential for enhanced denitrification (and hence nitrite accumulation) that is independent of the anammox competition for nitrite. It is documented in the literature that alcohols can be toxic to anammox bacteria. Therefore, for the application of a specific carbon source, it is necessary to protect anammox bacteria from potential toxicity in a two-step sludge system applying denitrification and anammox steps. Alternatively, operation of thick biofilms or granules, or electron donor-limited operation, can achieve the same protection.

[0035] Overall, the energy donor for denitritation, denitrification, or denitrification reactions can be any degradable carbon source, including alcohols including but not limited to glycerol, methanol, ethylene glycol, ethanol; volatile fatty acids including but not limited to acetate, acetic acid; carbohydrates including but not limited to sugars, starch or cellulose, carbon in wastewater, carbon in industrial waste or manufacturing byproducts, methane, aldehydes or ketones; or any inorganic electron donor such as sulfur or ferrous sources. While we used glycerol, methanol, ethanol, and acetate in our experiments, other electron donors can be used to achieve denitrification.

[0036] An important factor for successful application in non-acclimated sludge involves balancing the activity ratio between denitrifiers and anammox bacteria to achieve a balance between the ammonium removal and total nitrogen removal ratio. To demonstrate the importance of this factor, an additional set of activity tests was performed which showed that an increase in the ratio between the maximum anammox potential and the observed nitrate ratio (controlled by the addition of COD) resulted in an increase in denitrification (and thus ammonium removal) but also affected total nitrogen removal in a negative way Figure 2 ). This is mainly attributed to the factor that the nitrate rate more significantly determines the total nitrogen rate but ammonium removal is limited by the competition between anammox bacteria and denitrifiers for nitrite.

[0037] Figure 3 Control of denitrification and anammox reactions within a biofilm and / or synthetic matrix system is shown. Specific barriers to achieve biofilm thickness control can be used, typically about 50-400 um biofilm, to balance the energy donor and diffusion rate of nitrate selected for denitrification in a separate denitrification system controlled by direct sludge retention. Competition for space of biofilm, encapsulated matrix and sludge polymer or filler allows selection of denitritation and potential selection of specific denitrifying organisms.

[0038] In a one-step sludge system based on biofilm-based anammox retention, direct control of biofilm thickness (about 50-400 um (or, even more preferably, 50-400 um)) can manage the denitrification quality compared to the anammox quality Figure 3 ) and thus achieve selection of denitrification over total denitrification reactions. Alternatively, longer solid retention time biofilms (e.g. for anammox) can be formed on thin biofilms to reduce diffusion resistance. The proper balance between anammox quality and denitrification can determine the efficiency of ammonium removal as well as total nitrogen removal Figure 2 ). The same balance can be found by selection of proper particle size and / or encapsulated matrix size (50-2000 um).

[0039] Instead of biofilm thickness or particle size control, sludge retention time control achieves selection of denitrification over denitritation. In addition to energy donor limitation, sludge retention time can be limited or reduced to achieve selection. In a suspended system, time is the competing parameter instead of space (as in biofilm systems) Figure 3

[0040] Long-term addition of acetate Figure 4 ) in the last anoxic zone of the biological nutrient removal step as part of shortcut nitrogen removal process application was studied. The advantage of this application is that the need for aeration is reduced due to partial ammonium digestion by anammox and the need for electron donor is reduced for nitrate reduction reactions. Figure 5 ​This displays the long-term influent and effluent NOx levels of the denitrification system. Figure 4 (The last eight reactors shown). In this system, acetate is fed using a PID controller to maintain a nitrate residue concentration of 6-7 mg N / L. As a result, effective nitrite accumulation was achieved with an average nitrite concentration of 5.5 mg N / L. COD feeding was used to reduce nitrate residue, which was stabilized at a feeding rate of 2 g COD per gram of NO3-N added to the system. On average, a denitrification efficiency of 81 ± 9% was achieved. When organic carbon in the form of acetate was added to the plug flow system to reach 5 mg NO3-N / L in the first 30% anoxic reactor capacity and a similar COD was added to the first feed point to achieve complete denitrification at the second COD feed point (between the -50% point of the plug flow reactor) to generate 2 mg NO3-N / L, and after the third feed point, 0.5 mg NOx / L was generated in the wastewater (75% anoxic capacity point). Although the anoxic capacity increased, only a reduction in effective denitrification was observed in the first 30% anoxic capacity. It is assumed that the hypoxic SRT with increased nitrate residue concentration at lower levels reduces the established metabolic imbalance between nitrate reductase and nitrite reductase activities. Denitrification is expected to result in only about a 50% potential loss when operating with approximately 50% hypoxia capacity below 2 mg N / L of nitrate residue.

[0041] When the timing for denitrification occurs, nitrite can accumulate when the rate of anaerobic ammonium oxidation (ANAO) is limited in a single step. Since the accumulation of free nitrite restricts the growth of heterotrophic organisms, nitrite accumulation can increase the selectivity for denitrification. In some embodiments, autotrophic organisms (plants, algae, and certain bacteria) can be used in the same manner. However, heterotrophic organisms have shown to be more sensitive to free nitrite than nitrite-oxidizing organisms or ANAO. Therefore, even under suboptimal conditions, protecting ANAO in biofilms, packing materials, or encapsulation while exposing both the denitrifying and denitrifying organisms to higher free nitrite concentrations can stabilize denitrification, even under suboptimal conditions.

[0042] During anaerobic ammonia oxidation bioaugmentation and consequently nitrate and ammonium removal, a 212µm screen was used to selectively retain anaerobic ammonia oxidation while all other organisms (nitrifying bacteria, heterotrophic organisms, denitrifying organisms, and denitrifying organisms) operated at similar total SRT levels. Figure 4 Anaerobic ammonia oxidation granules are bio-enhanced daily from the side-flow deammoniation system, achieving a 5-30% anaerobic ammonia oxidation biomass fraction in the mixed liquid suspended solids.

[0043] When the correct electron donor is selected to feed the majority of the electrons upflow from cytochromes (and thus the nitrite reductase can get electrons), given the higher electron acceptance capacity between the given nitrate reductase and the nitrite reductase, the electron transport to the nitrite reductase is minimized until the nitrate concentration becomes limited. However, this imbalance can be minimized when the nitrite reductase can again get electron feed at low nitrate residuals using longer anoxic SRTs. Thus, a balance can be created between the minimum nitrate level at the right low nitrate level and the SRT to balance the requirement of only selecting the required discharge limiting denitrification. Overall, an average or medium nitrate residual concentration can be used to optimize the SRT needed to maintain a steady denitrification rate over a longer period of time. This is a key feature in using nitrate over a longer period of time constant to manage electron donor feed and over a longer period of time constant to manage SRT.

[0044] When used in combination, limiting electron donor supply and anoxic SRT also results in efficient denitrification, either due to selection of specific specialized bacteria or adaptation of general bacteria or a combination thereof.

[0045] Figures 6-8 is a graphical representation of several tests involving denitrification reactions or denitrification resulting from COD feed or nitrate residual adjustment over time. In the absence of anammox bacteria, the nitrite accumulation rate equals the nitrate reduction reaction rate, up to 2-3 mg N / L nitrate levels at a limited COD addition of acetate-COD / NOx-N of 3, with hourly additions of Figure 6 A1). At lower nitrate levels (<2 mg N / L), complete denitrification reactions are established.

[0046] When the test is performed with more COD added hourly to the system (COD / NOx-N of 10) in non-limited conditions, a reduced nitrate removal rate is observed at 4-5 mg NO3-N / L nitrate levels Figure 7 C1). However, at this point the nitrate to nitrite conversion is still 100% and thus no total nitrogen removal is observed. Similar to the test with lower COD / N feed, complete denitrification reactions also start at nitrate residuals of 2-3 mg NO3-N / L in this test Figure 7 C2). This indicates that nitrate residuals are beneficial for denitrification when the COD is non-limited.

[0047] Concentrated anammox sludge source from a side-stream deammonification reactor (675 mg VSS / L) was mixed to the main stream sludge (790 mg VSS / L) as Figure 6 The same test was performed. A1 was performed with a COD / N addition of 3, with hourly additions of Figure 8E1). The presence of soluble COD in the test fluctuated between 23 and 42 mg COD / L without any cleaning trend allowing the calculation of the COD removal rate (also Figure 6 A1). The addition of anammox sludge removed the nitrite accumulation and thereby the potential influence of nitrite or nitrite on the selectivity of 100% denitrification. This test showed that there was a decrease in denitrification from the nitrate level of 2 mg N / L (thereby complete denitrification reaction) and thereby a similar level was observed. Figure 6 A1 showed similar results as the initial results. When the NO3-N residual was greater than 3 mg N / L, the stoichiometry factor between the nitrate removal rate and the ammonium removal rate was observed to be 1.48, which is close to the theoretical anammox stoichiometry factor of 1.32.

[0048] Figure 9 A summary of the last anoxic zone of the main pilot is provided, acetate addition was 3 and 0 (A), 3 (B) and 12 (C) COD / NOx per 20 minutes and COD / N per 60 minutes. The potential of the denitrification reaction in the cell relative to the dosing of NO3 residual per 60 minutes is shown in panel D. At steady state operation, the dosing of acetate to stabilize the COD / NOx ratio was 2-3 to achieve a nitrate level of 5 mg N / L in the wastewater. To test the importance of the nitrate residual, acetate was additionally fed at a 60 minute residence time in the anoxic plug flow zone of the main pilot. The additional feeding of COD / NOx of 3 caused the nitrate to decrease to 2 mg N / L, a nitrate level greater than 5 mg N / L was observed, and the denitrification remained effective but slightly decreased to 80% denitrification (rather than 100% denitrification Figure 9 ). The higher feeding (COD / N 12) thereby the nitrate level was 0.1 mg N / L, complete denitrification reaction and thereby nitrite removal was observed Figure 9 . This correlates well with the observations in the batch experiments.

[0049] The present disclosure is applied as a one-step-sludge system, where both the denitrification reaction and the anammox reaction occur in the same reactor system in suspension, biofilm, granules, or a combination of suspension, biofilm, and / or granules. The anammox sludge retention time is enhanced using a continuous batch reactor, carriers, support materials, screens, cyclones, airlift reactors, magnetic separators, clarifiers, or any other specific gravity determination, flotation, and filtration equipment. In use, the control of the denitrification SRT can be managed by biofilm thickness control, hydraulic retention time control, bulk sludge retention time control, or it can depend on the system conditions Figure 2 . Figure 10 A, 11A2, and 12A show examples of applications.

[0050] The present disclosure can be applied in a two-step-sludge system where the denitrification reaction is controlled separately from the anammox step. Denitrification control is based on a combination of COD limitation, nitrate residual and SRT. SRT control can be performed by, for example, wasting suspended biomass, bioaugmentation, biofilm thickness control, setting rate selection, based on selected or retained particle size or particle density. Organisms that perform only the partial reduction step from nitrate to nitrite can be used, retained or selected and grown on suspended solids, granules, media or encapsulations. Denitrifying organisms can be retained or selected using supports such as support carriers, sand, anthracite, wood chips, stones, membrane biofilm or encapsulated in pure or mixed culture media, electron donor rich media, electron acceptors or micronutrient rich media. Alternatively, denitrifying organisms can be retained by physical selectors such as screens, cyclones, airlift reactors, magnetic separators, clarifiers or other devices for specific gravity determination, flotation and filtration. The anammox step is then performed in a second reactor or reactor zone on the formed nitrite and ammonium. Anammox in this step is performed by the same selection techniques as applied in one-step systems. The advantage of this approach is that denitrification selection is performed completely independently from anammox selection and a more specific organism selection is achieved. Examples of applications are shown in Figures 1 1 B2 and 12B. Figure 10 B, 11 B2 and 12B show.

[0051] In all embodiments, bioaugmentation with anammox organisms or denitrifying organisms can be added to the process from other reactors, zones or locations. Also, bioaugmentation with one or more selected organisms cultivated in the embodiments can be bioaugmentation to other applications and reactors. The BNR reactor can receive bioaugmentation with heterotrophic or autotrophic organisms, including anammox organisms from high strength reactors with reactor feed concentrations of greater than 200 milligrams of ammonium nitrogen per liter. Bioaugmentation of organisms can be in suspended form, grown on substrates, granules or attached to plastic, sand, anthracite, expanded clay, ceramic, sponge, activated carbon, magnetite, alumina, silica, porous or non-porous rock, wood chips or cellulose rich material, starch or other carbon containing support material, selective inhibition material, iron or iron rich material, stones, shells, rubber, resins including nitrate or ammonium selective resins, membrane biofilm or encapsulated in pure or mixed culture media, electron donor rich media, electron acceptors or micronutrient rich media.

[0052] The apparatus / process can be applied by itself when ammonium and oxidized nitrogen species are already present in the water / wastewater substrate. Figure 10 The energy donor can be added as an external source or it can be integrated into the wastewater stream. Figure 10

[0053] To obtain the correct ammonium to oxidized nitrogen treatment rate in the process, a bypass of the ammonium stream can be used in different applications. Figure 11 and 12 ​​

[0054] The apparatus / process can be applied in the biological nutrient removal step as a dedicated zone(s) with external energy donor addition Figure 12 A3.1 and 12B3.1). In addition, it can be integrated as a (first) anoxic zone receiving NOx return and carbon source from the wastewater and / or externally. Subsequent application can achieve enhanced nitrogen removal in the biological system with minimal input of electrical energy such as for aeration and for external carbon source for complete denitrification reaction. In this configuration, the addition of anammox can achieve shortcut nitrogen removal in the mainstream without the need to select for efficient nitrite oxidizing bacteria, which is identified as a major challenge in the art. The present disclosure overcomes the existing limitations by requiring a focus on de-nitrification rather than nitritation.

[0055] Figure 10 , 11 In the application shown in Figures 12, sensors or measurements can be used to control the ammonium concentration in the wastewater to be about half a mg N / L to two mg N / L. The latter target is observed to be a constant half-saturation for the anammox organisms in the mainstream application and thus can be considered as the minimum ammonium concentration that can be achieved without observing a loss in anammox rate.

[0056] The apparatus / process can be applied as a post-treatment to a biological nutrient removal system Figure 11 The preferred ammonium to NOx ratio required for efficient nitrogen removal in the process can be managed by appropriate aeration control within the biological nutrient removal system or by using a bypass of the wastewater containing ammonium. The biological nutrient removal system can have any suitable configuration, including the incorporation Figure 12 Preferred applications within biological systems.

[0057] The biological application removal reactor (BNR) can be an activated sludge process, a filter, a single- or multi-media filter, an upflow or downflow biological anoxic or aerated filter, a fabric filter, a fluidized bed reactor, a continuous return filter, a trickling filter, an integrated solids membrane activated sludge process, a polymerization membrane biofilm reactor, a ceramic membrane biofilm reactor, a moving bed biofilm reactor, a membrane bioreactor, or a combination of any of these reactors.

[0058] The BNR system has a capacity or a series of capacities and is thus equipped to add electron donors or organic substrates in one or more of the capacities. The multiple capacities can be in distinct vessels, multiple zones of a single vessel, single or multiple media in a single or multiple filters or reactors.

[0059] The filter or reactor media can be plastic, sand, anthracite, expanded clay, ceramic, sponge, activated carbon, magnetite, alumina, silica, porous or non-porous rock, wood chips or cellulose-rich material, starch or other carbon-containing support material, selective inhibitor material (e.g. nitrite or free nitrous acid containing material that inhibits specific organisms but not others), iron or iron-rich material, stone, shell, rubber, resins including nitrate or ammonium selective resins, biofilm or encapsulated in pure or mixed media, electron donor-rich material, electron acceptor or micronutrient-rich.

[0060] The apparatus can be integrated into a multi-zone moving bed bioreactor or multi-zone filter system or membrane biofilm reactor or suspended growth, or a series of combinations thereof, with a first zone including denitrification and anammox reaction zones where electron donor is controlled to achieve nitrate residuals, followed by an optional second denitrification reaction zone where optional additional electron donor is added to achieve complete denitrification and low nitrate concentrations, and an optional last post-aerobic zone to remove residual ammonium, added after the first or second zone, as needed based on ammonia treatment goals. With this configuration, the zones can be stages of a multi-stage reactor, separated by visual or real walls. The zones can be polymers such as core or shell portions, biofilm or granular Figure 3 ) media within a multi-media filter or partitions between shaded and non-shaded within the following media.

[0061] Aerobic oxidation of ammonium to nitrite or nitrate can also be achieved by using aerated biofilm reactors within an anoxic zone.

[0062] The apparatus / process according to the present disclosure can be applied as a two-zone process, where denitrification and / or complete denitrification reactions are used as a pretreatment prior to partial nitritation-anammox system removal of organics that can be toxic to aerobic ammonium-oxidizing bacteria and / or anoxic ammonium-oxidizing bacteria prior to their arrival at the organics. Nitrate formed within the partial nitritation-anammox partial stage can be recycled to the denitrification stage to provide sufficient electron acceptor. The amount of electron donor provided can be controlled by dilution of the wastewater stream using nitrate recycle flow rates.

[0063] The wastewater treatment apparatus can include, if desired, a biological nitrogen removal reactor having a capacity or a series of capacities, wherein the reactor is configured for the addition of an electron donor or organic substrate in one or more of the capacities, an oxidized nitrogen sensor for generating an oxidized nitrogen signal such as nitrate, nitrite, nitrous oxide, nitric oxide, or combinations thereof, a controller for processing the oxidized nitrogen signal whereby the addition of the electron donor or organic substrate is controlled to limit the heterotrophic production of nitrite, controlling conditions along the flow path or along the process timeline, wherein the controlled addition of the electron donor or organic substrate is set to a nitrate concentration measured on-line or off-line of greater than 1.5 mg / L nitrate nitrogen, in more than 50% of the reactor capacity in space or time.

[0064] Within the controller, the electron donor or organic substrate feed rate can be set and its upper and lower limits can be changed depending on the desired nitrate, nitrite, or ammonium concentration exiting or entering the system.

[0065] The wastewater treatment apparatus can be one including a biological nitrogen removal reactor having a capacity or a series of capacities, wherein the reactor is configured for the addition of an electron donor or organic substrate in one or more of the capacities; an oxidized nitrogen sensor for generating an oxidized nitrogen signal such as nitrate, nitrite, nitrous oxide, nitric oxide, or combinations thereof, and an ammonia sensor that probes the ammonia concentration in the reactor and generates an ammonia signal. According to one aspect of the disclosure, a controller generates instructions for increasing, decreasing, or maintaining an upper limit of a nitrate setpoint, an ammonium setpoint, an electron donor or organic substrate concentration, or a COD feed rate to maximize total nitrogen removal or to minimize ammonium, nitrite, or nitrate residuals and to maintain an ammonia setpoint of about half a milligram to two milligrams of nitrogen per liter in the wastewater to maximize an anammox reaction.

[0066] Anammox organisms can use some types of electron donors or organic substrates, such as volatile fatty acids, acetate, propionate, formate, or electron donor products or intermediates from glycerol for denitrification. Thus, both nitrate reduction and anoxic ammonium oxidation can be carried out simultaneously by anammox organisms.

[0067] The addition of the electron donor or organic substrate can also be controlled based on a nitrate setpoint and thereby controlled by only an oxidized nitrogen sensor or a combination of an oxidized nitrogen sensor and an ammonia sensor. Both signals can be used by the controller to generate instructions for increasing, decreasing, or decreasing an upper or lower limit of a nitrate setpoint, an ammonium setpoint, an electron donor or organic substrate concentration, or a COD feed rate to maximize total nitrogen removal or to reduce ammonium, nitrite, or nitrate.

[0068] Residual sludge retention time for denitrifying organisms can be accomplished by managing anoxic volume or time, managing waste rate, by backwashing solids, or by controlling biofilm thickness. The latter can be accomplished by selecting appropriate media and by physical or chemical attrition techniques including, but not limited to, cyclonic, airlift reactors, sieving, mixing, and air refining.

[0069] Within a biofilm system, two types of biofilms can be differentiated. Shaded biofilms are biofilms that grow on the surface of media protected in a pore or in a protected area of media. Such biofilms are protected from physical shear forces and biofilm thickness and / or retention is determined by microbial activity and microbial kinetics. Shaded biofilms are important for slow growing organisms (e.g., anammox organisms or organisms) that require a relatively longer SRT compared to their competing organisms (e.g., autotrophic organisms). Examples of media that can support shaded biofilms include, but are not limited to, expanded clay, ceramic, lava, iron-rich materials, plastic, or activated carbon. In addition to shaded biofilms, iron-rich materials can provide trace nutrients for anammox growth and assist in biofilm attachment. A second type of biofilm is a non-shaded or erosional biofilm that is subjected to backwashing, air scouring, or shear and such biofilms are controlled by physical forces rather than microbial kinetics. Within such biofilms, fast growing organisms such as heterotrophic organisms can grow, but their solids retention time can be controlled using physical forces. Media that support the second type of biofilm include, but are not limited to, sand, anthracite, clay, or plastic.

[0070] To maintain different SRTs between denitrifying organisms and anammox organisms, anammox can be selected to grow in shaded biofilms and denitrifying organisms can be selected to grow in non-shaded biofilms. Particularly in filter or fluidized bed biofilm reactors, where SRT control can only be accomplished by physical forces, it is important to protect anammox organisms from these forces to maintain the potential for ammonium removal. Single or multi-media used in accordance with the present disclosure thus have a combination of shaded and erosional biofilms to maintain different solids retention times to support different organism groups, including denitrifying organisms, anammox organisms, or combinations thereof.

[0071] The conversion from nitrate to nitrite during the denitrification reaction is a faster rate compared to the nitrite reduction reaction, especially when nitrate residuals are present. Therefore, a lower SRT operation will gradually select for more specialized denitrifying organisms or result in a selective denitrification capacity for specialized organisms compared to an operation with a long SRT that will maintain a more diverse population structure (composition) or function. Once a more specialized population or function is selected, characterized by a lack of denitrification reaction genes or a reduced expression of genes, the selection for a subsequent denitrification step, nitrate residuals can potentially be reduced while maintaining sufficient partial denitrification (denitrification). The longer the SRT, the potentially higher nitrate residuals are required to select for efficient denitrification.

[0072] Since the controller determines the electron donor or organic substrate feed based on the nitrate setpoint, the time varying electron donor feed rate can provide an indication of the process efficiency. A higher electron donor rate, given a similar nitrate removal rate, or when the electron donor rate is normalized to the nitrate removal, is an indication of a lower denitrification selectivity efficiency and, more importantly, it is an indication of (i) a higher nitrate setpoint (option 1) and / or (ii) an increased waste rate (option 2), or a control waste device frequency increase. The first option (increased nitrate setpoint) can be implemented at a maximum nitrate reduction rate operation resulting in a rate difference with the subsequent denitrification step and thereby nitrite accumulation to thereby increase the potential ANAMMOX contribution while maximizing or minimizing the electron donor addition. At a reduced SRT operation (option 2), the growth selection for denitrification over complete denitrification is again achieved by using the kinetic rate difference between the nitrate reduction reaction and the nitrite reduction reaction.

[0073] The determination of option 1 or option 2 is determined by a time step. While the change in the nitrate setpoint is a short-term decision and thereby a fast reaction, the SRT selection is a slower response and the change in the waste rate is determined based on an average electron donor evaluated over an extended period of time. Also, the change in the nitrate setpoint is a more adaptive option for reactor types that do not allow for a precise SRT control, for example, mobile biological reactors and filters. Options 1 and 2 can be combined in an overall SRT control strategy by determining the waste rate and by evaluating the change in the nitrate setpoint over an extended period of time to determine the SRT of the system compared to the set nitrate setpoint.

[0074] Based on the foregoing, the anoxic solids retention time associated with the reactor can be controlled by adjusting the flow rate or frequency of fluid device waste or backwash of solids, by sensing and measuring the COD feed rate and / or nitrate, nitrite and ammonium removal rate appropriate for maximizing process rates of denitrification and / or anammox within the reactor to maintain a specific COD or electron donor feed rate or normalized COD feed or electron donor rate per total inorganic nitrogen removal.

[0075] Alternatively, the anoxic solids retention time associated with the reactor can be controlled by adjusting the flow rate or frequency of fluid device waste or backwash of solids, by maintaining a specific nitrate setpoint by sensing and measuring the nitrate concentration appropriate for maximizing process rates of denitrification and / or anammox within the reactor.

[0076] If nitrite wastewater levels are observed, due to lack of anammox contribution or ammonium limitation, a lower nitrate residual can be selected to increase electron donor addition and achieve increased complete denitrification. This can prevent nitrite discharge. On the other hand, nitrite and / or nitrate concentrations from the partial denitrification-anammox step can be removed from the wastewater by an additional denitrification reaction step. In this step, any of the electron donors in the wastewater from the previous steps can be used or an electron donor can be provided to reduce the nitrate and nitrite to di-nitrogen gas. Alternatively, when nitrate limitation is allowed, nitrite can be oxidized to nitrate in a post-aerobic step to prevent nitrite discharge. The additional denitrification reaction step and / or the additional aerobic step can be implemented spatially or temporally in the BNR system.

[0077] It is desirable to maintain an ammonium residual (0.5-2 mg N / L) to increase anammox rates and thereby provide increased nitrite pools in the system. This enables easier control of the partial denitrification selection. The ammonium setpoint can be selected based on discharge limitations or desired anammox contribution. The ammonium concentration measured by an ammonia sensor for detecting ammonia in the reactor and for generating an ammonia concentration difference signal is compared to a defined setpoint. A controller processes the ammonia signal and the difference to the setpoint and controls the upper or lower limit of the COD feed, the nitrate or nitrite setpoint, the dissolved oxygen concentration, the time duration of the aerobic phase, and / or the anoxic time duration in one or more volumes of the reactor.

[0078] When the ammonium residual is too low, the lower limit of the COD feed rate in the controller can be changed, the nitrate setpoint increased, or the dissolved oxygen concentration decreased or the capacity of the aerobic zone decreased to minimize ammonium oxidation. When the ammonium is too high, the anammox activity is limited, and it is desired to increase the competition for nitrite by increasing the nitrate setpoint, decreasing the SRT, to wash out the denitrifying organisms, decrease the upper limit of the COD feed rate in the controller, increase the anoxic time to give the reaction more time, or increase the aerobic oxidation by increasing the dissolved oxygen concentration or increasing the capacity or time of the aerobic zone.

[0079] The electron donor feed can be controlled to meet the wastewater nitrate setpoint. However, to further maximize the anammox activity, as indicated by the ammonia removal, the in- and outflow (or process) can be controlled using online ammonia and nitrate sensors, the upper limit of the carbon feed can be controlled using the rate of nitrate removal to ammonia removal, so that maximum (or improved) nitrogen removal is achieved and the anammox activity is maximized (or improved).

[0080] One or more computer algorithms can be developed using machine learning, artificial intelligence, or neural networks to develop an electron donor feed protocol that includes, but is not limited to, the influent chemical oxygen demand to influent milligrams of nitrate-nitrogen ratio requirement, residual nitrate-nitrogen concentration, and anoxic solids retention time associated with the first reaction. Such algorithms exist in the edge computing FOG computing or cloud computing framework, where the algorithms are periodically refined.

[0081] Figure 13 An apparatus, information, and signal processing line for managing the first reaction (nitrate reduction reaction to nitrite) is shown that controls the electron donor addition to maintain a limited electron donor availability to maintain a nitrate residual in the anoxic zone. A sludge retention time (SRT) controller is combined with a given nitrate residual for optimizing the SRT. As shown Figure 13 Optional sensors or measurement means can include sensors for oxidized nitrogen and / or ammonium.

[0082] According to Figure 13 In one embodiment, wastewater is received through an influent channel, which receives an electron donor from an electron donor channel that is fitted with a valve, and which is added to an anoxic zone. A sensor generates a signal representative of the concentration of nitrate in the anoxic zone, which can be, for example, a NOx sensor. The signal is received by a controller, which responds to the signal by generating a control signal to control the valve of the electron donor channel, thereby maintaining a desired nitrate residual concentration in the anoxic zone.

[0083] According to Figure 13One embodiment is shown in which wastewater is received through an influent channel, which receives electron donors from a valved electron donor channel, and which is fed to an anoxic zone. A solids / liquid separator (S / L) separates a solids (sludge) stream from the influent to the anoxic zone. Depending on the control of the valves (later valves shown below the anoxic zone and solids / liquid separator (S / L)), the solids stream can be (1) returned to the anoxic zone or (2) wasted. Return / waste / backwash valves are controlled by a controller to maintain the desired solids residence time (SRT) in the process. The SRT setpoint, backwash frequency, washout of denitrifying organisms, or the like are controlled based on the average nitrate residual concentration. The absolute value of the SRT and / or the biofilm thickness can never be known, but the relative nature of the SRT can be inferred from metabolic behavior or overall denitrification or anammox reactions. Figure 13

[0084] Figure 15 Figure 13 is an algorithm for the controller. As shown in Figure 15 , the controller can include control logic for selecting a partial denitrification reaction (nitrate to nitrite reduction reaction) by controlling the COD / N feed rate to maintain a nitrate residual in the anoxic zone equal to or above 1.5 mg N / L. The minimum and maximum COD / N feed rate settings can be adjusted based on the desired ammonium removal rate or anammox removal rate or the optimized relative SRT.

[0085] Figure 14 is an algorithm for the controller. As shown in Figure 13 , the controller can include control logic for selecting a partial denitrification reaction (nitrate to nitrite reduction reaction) by controlling the electron donor rate to maintain a nitrate residual in the anoxic zone equal to or above 1.5 mg N / L. The minimum and maximum electron donor rate settings can be adjusted based on the desired ammonium removal rate or anammox removal rate or the optimized relative SRT. Figure 14

[0086] Figure 16 Figure 13 is an algorithm for the controller. As shown in Figure 16 , the controller can include control logic for selecting a partial denitrification reaction (nitrate to nitrite reduction reaction) by controlling the waste stream rate or frequency of wasting equipment to maintain a nitrate residual in the anoxic zone. The time constant of this control loop is longer than the electron donor addition control and allows for stabilization of the selected microbial population. The relative optimized SRT setpoint associated with the preferred nitrate concentration depends on the wastewater characteristics and the reactor technology used. The minimum and maximum COD / N feed rate settings can be adjusted based on the desired ammonium removal rate or anammox removal rate or the optimized relative SRT.

[0087] ​​​​Reference

[0088] Kazulyuzhnyi, S., et al. (2007). "Phylogenetic analysis of microbial population in DEAMOX reactor performing anaerobic ammonium oxidation under sulfide-driven conditions." Poster presentation at the 11th World Congress on Anaerobic Digestion, Brisbane, Australia, September 23-27, 2007.

[0089] Kalyuzhnyi, S., Gladchenko M., Mulder A., and Versprille B. (2006). "DEAMOX - a novel biological nitrogen removal process based on sulfide-driven anaerobic ammonium oxidation coupled to nitrate to nitrite." Water Res., 40, 3637-3645.

[0090] PENG YONGZHEN et al., "Method and apparatus for nitrogen removal from sludge supernatant liquid by three-step shortcut denitrification process - anaerobic ammonium oxidation - shortcut nitrification process", Chinese patent CN105923774 (A). September 7, 2016.

[0091] It is to be understood that the various disclosed embodiments shown and described above are merely illustrative of the different possible features which can be combined in different ways. Other improvements within the scope of the present disclosure are also contemplated in addition to combining the features of the above embodiments in different ways. The present disclosure is not intended to be limited to the preferred embodiments described above, but rather is to be limited only by the claims which follow. Thus, the present disclosure includes all alternatives falling within the scope of these claims.

[0092] The present disclosure is not limited to the structures, methods and means shown and described above. The present disclosure is defined by the claims which follow.

Claims

1. A wastewater treatment method comprising: receiving wastewater in a multi-zone process, wherein the zones are spatially separated; performing biological nitrogen removal on the wastewater in the multi-zone process, wherein the biological nitrogen removal comprises a partial denitrification reaction, wherein nitrate is reduced to nitrite under anoxic conditions, and an anammox reaction, wherein the nitrate is used as an electron acceptor under anoxic conditions; adding an electron donor to the multi-zone process through a bypass during the biological nitrogen removal, wherein the electron donor comprises a degradable carbon source, the degradable carbon source comprising an alcohol, a volatile fatty acid, a carbohydrate, wastewater carbon, carbon from industrial waste or manufacturing byproducts, methane, an aldehyde or a ketone, and / or an inorganic electron donor; wherein the electron donor is added in a dedicated anoxic zone and the electron donor feed satisfies effluent nitrate requirements for more than 50% of the reactor or filter capacity spatially; and wherein the biological nitrogen removal is controlled using additional online ammonia and nitrate sensors flowing on the dedicated anoxic zone.

2. The method of claim 1, wherein, the inorganic electron donor comprises ammonia.

3. The method of claim 1, wherein, further comprising ammonia measurement.

4. The method of claim 1, wherein, the addition of the electron donor feed comprises a feed to maximize ammonia removal: wherein, using a target ratio of nitrate removal to ammonia removal controls the upper limit of carbon feed, thereby achieving maximum nitrogen removal.

5. The method of claim 1, wherein all or a portion of the nitrite generated is reduced to dinitrogen gas by anammox bacteria.

6. The method of claim 1, further comprising bioaugmentation with heterotrophic or autotrophic organisms, including but not limited to anammox organisms from high strength reactors having feed concentrations greater than 200 mg ammonium nitrogen per liter.

7. The method of claim 1, wherein, maintaining between half a milligram and two milligrams of ammonia per liter in the effluent to maximize the anammox reaction.

8. The method of claim 1, further comprising maintaining an electron donor feed rate per total inorganic nitrogen removal or a normalized electron donor feed rate by probing or measuring an electron donor feed rate and / or a nitrate, nitrite, or ammonium removal rate appropriate for maximizing the rate of denitrification and / or anammox within the biological nitrogen removal.

9. The method of claim 1, wherein the biological nitrogen removal uses filter or reactor media comprised of plastic, sand, anthracite, expanded clay, ceramic, sponge, activated carbon, magnetite, alumina, silica, porous or non-porous rock, wood chips or cellulose-rich material, starch or other carbon-containing support, iron or iron-rich material, stone, shell, rubber, resins including nitrate, nitrite, or ammonium selective resins, membrane biofilm, or encapsulated in a pure or mixed culture medium, or enriched with electron donor, electron acceptor, or other micronutrients.

10. The method of claim 1, wherein, the multiple zones comprise different vessels, within a single vessel, single or multiple media, single or multiple aggregates, biofilm or granules, or other synthetic processes' multiple buffer or virtual stages in a single or multiple filters or reactors.

11. The method of claim 1, further comprising providing anaerobic ammonia oxidation bacteria and retaining the anaerobic ammonia oxidation bacteria in the multiple zones by a physical selector comprising a screen, a cyclone, an air lift reactor, a magnetic separator, or any other specific gravity determination, floatation, or filtration device.

12. The method of claim 1, wherein the anaerobic ammonia oxidation reaction comprises conversion of ammonium to dinitrogen gas by anaerobic ammonia oxidation bacteria.

13. A wastewater treatment method comprising: receiving wastewater in a multiple zone process, wherein the zones are spatially separated; performing biological nitrogen removal on the wastewater in the multiple zone process, wherein the biological nitrogen removal comprises a partial denitrification reaction, wherein nitrate is reduced to nitrite under anoxic conditions, and an anaerobic ammonia oxidation reaction, wherein the nitrate is used as an electron acceptor under anoxic conditions; adding an electron donor or organic substrate to the multiple zone process through a bypass during biological nitrogen removal, wherein the electron donor comprises a degradable carbon source comprising an alcohol, a volatile fatty acid, a carbohydrate, wastewater carbon, carbon from industrial waste or manufacturing byproducts, methane, an aldehyde or ketone, and / or an inorganic electron donor; and processing a measurement of an oxidized nitrogen concentration to maintain at least a residual amount of nitrate in the multiple zone process while maximizing reduction of the nitrate in the partial denitrification reaction, wherein the oxidized nitrogen concentration comprises an in-line or off-line measured nitrate concentration associated with the partial denitrification reaction, wherein the method further comprises adding an electron donor or organic substrate to the multiple zone process during biological nitrogen removal, and performing the addition of the electron donor or the organic substrate such that the nitrate concentration is above a set value or lower limit, and wherein the addition of the electron donor or the organic substrate is controlled and set such that the in-line or off-line measured nitrate concentration is above 1.5 mg / L nitrate nitrogen, spatially more than 50% of the reactor or filter capacity; wherein the electron donor is added within a dedicated anoxic zone and the electron donor feed satisfies effluent nitrate requirements for spatially more than 50% of the reactor or filter capacity; and wherein the biological nitrogen removal is controlled using additional in-line ammonia and nitrate sensors flowing over the dedicated anoxic zone.

14. The method of claim 13, wherein, the inorganic electron donor comprises ammonia.

15. The method of claim 13, wherein all or a portion of the nitrite generated is reduced to dinitrogen gas by anaerobic ammonia oxidation bacteria.

16. The method of claim 13, wherein, the electron donor comprises a degradable carbon source comprising: a alcohol; b volatile fatty acid; c carbohydrate; d wastewater carbon; e carbon from industrial waste or manufacturing byproducts; f methane; g aldehyde or ketone; and / or h inorganic electron donor.

17. The method of claim 13, maintaining an ammonia setpoint of semi-milligrams to two milligrams of nitrogen per liter in the effluent to maximize the anaerobic ammonia oxidation reaction.

18. The method of claim 13, further comprising maintaining an electron donor feed rate per total inorganic nitrogen removal or a normalized electron donor feed rate by probing or measuring an electron donor feed rate and / or a nitrate, nitrite or ammonium removal rate appropriate for maximizing process rates for the biological nitrogen removal endodenitrification and / or anaerobic ammonium oxidation.

19. The method of claim 13, wherein the biological nitrogen removal uses filter or reactor media comprised of plastic, sand, anthracite, expanded clay, ceramic, sponge, activated carbon, magnetite, alumina, silica, porous or non-porous rock, wood chips or cellulose-rich material, starch or other carbon-containing support, iron or iron-rich material, stone, shell, rubber, resins including nitrate, nitrite or ammonium selective resins, membrane biofilm or encapsulated in a pure or mixed culture medium, or enriched in electron donor, electron acceptor or other micronutrients.

20. The method of claim 13, wherein, The multiple zones include different vessels, single vessel, single or multiple media, single or multiple aggregates, biofilm or granules, or other synthetic process multiple buffer or virtual stages in single or multiple filters or reactors.

21. A wastewater treatment method comprising: receiving wastewater in a multiple zone process, wherein the zones are spatially separated; performing biological nitrogen removal on the wastewater in the multiple zone process, wherein the biological nitrogen removal includes a partial denitrification reaction in which nitrate is reduced to nitrite using methane as an electron donor under anoxic conditions, and an anaerobic ammonium oxidation reaction in which the nitrate is used as an electron acceptor under anoxic conditions; wherein the multiple zone process uses filter or reactor media comprised of plastic, sand, anthracite, expanded clay, ceramic, sponge, activated carbon, magnetite, alumina, silica, porous or non-porous rock, wood chips or cellulose-rich material, starch or other carbon-containing support, iron or iron-rich material, stone, shell, rubber, resins including nitrate, nitrite or ammonium selective resins, membrane biofilm or encapsulated in a pure or mixed culture medium, or enriched in electron donor, electron acceptor or other micronutrients; and wherein the multiple zones include different vessels, single vessel, single or multiple media, single or multiple aggregates, biofilm or granules, or other synthetic process multiple buffer or virtual stages in single or multiple filters or reactors; wherein the electron donor is added in a dedicated anoxic zone and the electron donor feed satisfies the effluent nitrate requirement for more than 50% of the reactor or filter capacity spatially.

21. A wastewater treatment method comprising: receiving wastewater in a multiple zone process, wherein the zones are spatially separated; performing biological nitrogen removal on the wastewater in the multiple zone process, wherein the biological nitrogen removal includes a partial denitrification reaction in which nitrate is reduced to nitrite using methane as an electron donor under anoxic conditions, and an anaerobic ammonium oxidation reaction in which the nitrate is used as an electron acceptor under anoxic conditions; wherein the multiple zone process uses filter or reactor media comprised of plastic, sand, anthracite, expanded clay, ceramic, sponge, activated carbon, magnetite, alumina, silica, porous or non-porous rock, wood chips or cellulose-rich material, starch or other carbon-containing support, iron or iron-rich material, stone, shell, rubber, resins including nitrate, nitrite or ammonium selective resins, membrane biofilm or encapsulated in a pure or mixed culture medium, or enriched in electron donor, electron acceptor or other micronutrients; and wherein the multiple zones include different vessels, single vessel, single or multiple media, single or multiple aggregates, biofilm or granules, or other synthetic process multiple buffer or virtual stages in single or multiple filters or reactors; wherein the electron donor is added in a dedicated anoxic zone and the electron donor feed satisfies the effluent nitrate requirement for more than 50% of the reactor or filter capacity spatially.

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