Efficient and stable operation method for non-nitrite-dependent anaerobic ammonia oxidation process

Abstract

The invention discloses an efficient and stable operation method for a non-nitrite-dependent anaerobic ammonia oxidation process, and belongs to the technical field of water treatment. The method comprises the following steps: firstly, constructing an anaerobic ammonia oxidation system for synchronously supplying NO2 <-> and NH4 < + >; and then adding an extracellular electron acceptor substance. A high-compatibility extracellular electron acceptor with a conductive bridge is introduced on the basis of a mature anaerobic ammonia oxidation process, so that direct electrical connection of microorganisms-acceptor particles is established to activate redox communication of microbial populations, and the whole non-nitrite-dependent anaerobic ammonia oxidation biological denitrification system is constructed. The conductive bridge not only enhances the interface charge transfer flux to achieve efficient pollutant removal, but also creates a friendly cooperative microbial population to maintain long-term and stable operation of a nitrite-free participation system.

Description

Technical Field

[0001] The present invention belongs to the field of water treatment technology, and specifically relates to a method for efficiently and stably operating a non-nitrite-dependent anaerobic ammonium oxidation process. Background Art

[0002] In the context of net zero carbon emissions, anaerobic ammonium oxidation (ANAMMOX) has shown particular appeal for wastewater treatment due to its advantages such as low oxygen demand and no need for external carbon sources. It has been put into operation in more than 100 full-scale treatment plants around the world. This unique reaction is driven by a specific but non-purely culturable Candidatus bacterial community, which converts nitrite nitrogen NO2 into nitrite. - ) is used as an electron acceptor to convert ammonia nitrogen (NH4 + ) is oxidized to nitrogen (N2). In order to overcome the actual wastewater NO2 - Lack of challenges, using short-cut nitrification and short-cut denitrification to achieve NO2 - However, the electron acceptor (O2) for the short-range nitrification reaction and the electron donor (sodium acetate) for the short-range denitrification reaction are still continuously supplied to ensure the smooth conversion of nitrogen, which causes the sewage treatment plant to continuously spend aeration energy and investment in chemicals. ANAMMOX bacteria have been confirmed to be emerging electroactive bacteria with extracellular electron transfer capabilities. They use extracellular low-potential insoluble electron acceptors to couple extracellular respiration with ammonia oxidation, allowing ANAMMOX bacteria to operate in the absence of NO2. - Direct conversion of NH4 + Although ANAMMOX metabolism based on extracellular respiration has been widely confirmed, it has never been able to demonstrate satisfactory EET levels (denitrification contribution is only 20%-55%). This is attributed to the slow interfacial charge transfer between ANAMMOX bacteria and extracellular receptors, which in turn reduces the metabolic activity of functional microorganisms and hinders the rapid startup and stable operation of non-nitrite-involved devices.

[0003] Specifically, ANAMMOX bacteria are both the main component of the bioreactor and the most vulnerable component. Since they cannot be cultured in pure form, ANAMMOX bacteria must allocate cellular resources globally to compensate for their own metabolic integrity. Usually, microorganisms secrete communication molecules (quorum sensing QS) to sense the metabolic needs and product supply of surrounding companion bacteria, select partners in a complex environment, and jointly cope with nutritional deficiency challenges. However, in the absence of NO2 - In a bioreactor, the inability to generate NO will result in the inability to activate the QS signal transduction pathway, and ANAMMOX bacteria will face growth difficulties. Therefore, the stagnant species communication method is the potential reason why ANAMMOX cannot operate stably for a long time in a non-nitrite-dependent system. Among the many species communication methods, Fe-based 2+ / Fe 3+Interspecies communication via redox molecules has received considerable attention in electroactive microbial systems. 2+ / Fe 3+ The communication system not only has the ability to sense, analyze and process interspecies information, but also can coordinate microbial metabolic behavior to enhance the intensity of interspecies metabolite exchange. It is worth noting that the slow interfacial electron transfer flux between bacteria and materials is destined to be difficult to efficiently and stably stimulate redox communication. In order to achieve efficient interspecies communication, the present invention proposes a feasible hypothesis, namely, to build a "high conductivity bridge" to enhance the direct electrical contact between electroactive ANAMMOX microorganisms and extracellular nanoreceptor particles to improve the interfacial charge transfer flux. At the same time, under efficient interfacial charge transfer flux, the extracellular receptor material is no longer the final destination of ammonia electrons, but forms a redox communication signal (Fe 2+ ) is used to gather a friendly microbial community with ANAMMOX bacteria as the core, making it possible to rapidly increase the value of ANAMMOX microorganisms in the non-nitrite-dependent system, creating favorable conditions for the long-term stable operation of the new system. The present invention has for the first time formed a method for the efficient and stable operation of a non-nitrite-dependent anaerobic ammonium oxidation process, which can quickly build a complete non-nitrite-dependent ANAMMOX process, fundamentally paving the way for ANAMMOX technology to break through NO2 - It provides new ideas for solving supply problems, expands the application areas of ANAMMOX, and further improves the global understanding of nitrogen cycle, providing strong technical support and confidence guarantee for future engineering applications. Summary of the Invention

[0004] Taking into account the growth characteristics of ANAMMOX bacteria, non-nitrite-dependent ANAMMOX processes are usually faced with problems such as low denitrification levels (i.e., low denitrification contribution rate) and inability to operate for a long time (i.e., gradual loss of functional bacteria), which greatly hinder the practical promotion of new processes. Therefore, the present invention provides a non-nitrite-dependent anaerobic ammonia oxidation process with high efficiency and stable operation strategy, which improves interfacial charge transfer by artificially building a "conductive bridge" (fixed or mobile), establishes direct electrical contact between microorganisms and extracellular receptors, and quickly and comprehensively activates the extracellular respiration potential of ANAMMOX. Furthermore, high interfacial charge flux will also effectively trigger extracellular receptors to be redox signals (Fe 2+ / Fe 3+ The ANAMMOX process is a highly scalable, biocompatible, and biocompatible process that is designed to coordinate ANAMMOX population communication (through a cyclical pathway) and greatly expand the application breadth and treatment depth of the ANAMMOX process. However, due to the lack of directional electron transfer channels between ANAMMOX bacteria and extracellular receptors, as well as the disconnection of ANAMMOX interspecies communication, the efficient and stable activation of the non-nitrite-dependent ANAMMOX process is difficult.

[0005] To this end, the present invention provides the following technical solutions.

[0006] The efficient and stable operation strategy of the non-nitrite-dependent anaerobic ammonium oxidation process comprises the following steps:

[0007] Step 1. Build NO2 - and MH4 + The traditional ANAMMOX system supplied simultaneously prepares for the construction of non-nitrous system:

[0008] The inoculated sludge was added to the continuous flow reactor, and the sludge was heated with NO2 - and NH4 + The synthetic wastewater was used as the reactor inlet to activate the metabolic activity of ANAMMOX bacteria, and the hydraulic retention time was 6-8h.

[0009] The inoculated sludge characteristics must meet the following conditions:

[0010] A. The volume of the inoculated sludge accounts for 30-50% of the total volume of the reactor;

[0011] B. The total amount of suspended matter in the initial mixed liquid formed after stirring is 2000-3000 mg / L; and the mass ratio of volatile suspended matter (i.e. biomass content) to total suspended matter is 0.3-0.5 to ensure that there is a sufficient microbial population in the added sludge.

[0012] (1) The sewage in this step contains NO2 - NH4 + And medium solution containing trace elements: NH4 + The concentration is 40-80mg / L, NO2 - The configuration concentration is NH4 + 1.1-1.3 times the concentration; the medium solution usually contains 5-20mg / LPO4 3- -P, 50-80mg / LCaCl2, 500-1000mg / LKHCO3 and other trace elements to meet the nutritional needs of ANAMMOX;

[0013] (2) By adjusting the hydraulic retention time of the reactor, the total nitrogen removal rate in the effluent reached 85%-90%, and the traditional ANAMMOX biological denitrification system was successfully started;

[0014] Step 2: The present invention adds a highly compatible extracellular receptor material with a "conductive bridge" to the ANAMMOX system prepared in step 1 to in situ stimulate the electron transfer potential of AnAOB and gradually reduce the influent NO2 - / NH4 + Concentration ratio until influent NO2 -The ammonia-only wastewater was treated and the operational stability and efficiency of the completely non-nitrite-dependent ANAMMOX system were recorded.

[0015] Furthermore, the reactor may include a pH and DO meter, the probes of which are installed in the reactor to constantly monitor and control the pH and DO levels during the denitrification process, which is beneficial for the survival of functional bacteria. Preferably, the probes of the pH and DO meter are installed at the drain outlet of the reactor.

[0016] Furthermore, it also includes a raw water pool, which is connected to the water inlet through a water inlet pipe, and the artificial water distribution maintains the dissolved oxygen at 0.5-1.0 mgO2 / L through aeration.

[0017] The pH of the sewage is controlled at 7.5-7.8, and HCl or NaOH solution is used to adjust the pH of the sewage. Exemplarily, the concentration of the HCl or NaOH solution is 1M.

[0018] In addition, in addition to the ANAMMOX domestication and operation unit, the present invention also needs to be equipped with an extracellular electron acceptor material correction unit, that is, a high-conductivity electron transfer bridge is assembled on the periphery of the extracellular acceptor material to establish a direct electrical connection between the ANAMMOX bacteria and the extracellular acceptor material;

[0019] Furthermore, the selection of extracellular electron acceptor substances requires that the added substances have electron vacancies on their surfaces and reversible valence states, that is, their ionic redox / reduction states can be reversibly switched through electron transfer between electroactive bacteria and associated species: Fe2O3 nanoparticles, Fe3O4 nanoparticles, and electrodes that can produce hydrogen peroxide (H2O2) or hydrogen (H2) can be selected. Transition metal oxide Fe3O4 is preferred due to its superparamagnetism, highly reversible charge and discharge properties, and biosafety; considering that ANAMMOX bacteria, as iron-loving bacteria and iron-sources, participate in the synthesis of multiple functional proteins and heme; and iron-based oxides are widely available and inexpensive;

[0020] Furthermore, in order to facilitate the extracellular electron acceptor material to more quickly receive the expelled electrons of AMAMMOX, a "bridge" with a directional electron transfer route is added to the extracellular electron acceptor material, that is, a bio-electron transfer element with excellent conductive properties (resistance less than 30Ω) is selected to modify a highly compatible acceptor material. Preferably, carbon nanowires or carbon quantum dots (CDs) with low resistance and pseudo-capacitance characteristics are used as conductive bridges. On the one hand, the electrostatic repulsion between CDs can effectively improve the dispersion of extracellular receptors, expand the spatial distance between the acceptor material particles, and fundamentally overcome the problem of material agglomeration on the bacterial surface; on the other hand, CDs form an electric double layer structure (i.e., a parallel plate capacitor) with cations in water. The electric field force generated by the structure forces the bioelectrons to gather on the surface of CDs, and the electrons migrate at high speed along the predetermined orbit provided by CDs, thereby improving the electron transfer efficiency between donors and acceptors, which helps to further improve the self-assembly level and electron transfer ability of inorganic-biological hybrids.

[0021] Furthermore, the one-pot synthesis process of CDs material synthesis and its integration with extracellular receptors (taking Fe3O4 as an example) was completed in an independent modification unit. The specific process was to react ammonium ferric citrate, ethylenediamine monohydrate and deionized water in a ratio of 2.33 (g): 0.8 (ml): 20 (ml);

[0022] The solution was then transferred to a 40ml Teflon-lined microwave digestion tank and irradiated at 800W and 180°C for 10-12 minutes. The solution color changed from reddish-brown to dark brown, indicating the simultaneous carbonization and doping of Fe₃O₄ with the ethylenediamine-functionalized CDs to produce Fe₃O₄@CDs. After the reaction, the reactor was cooled to room temperature.

[0023] Furthermore, the obtained Fe3O4@CDs were centrifuged at 1600g-1800g for 10min-15min to precipitate non-fluorescent aggregates.

[0024] The supernatant was then dialyzed using a 500-100 Da dialysis membrane to harvest and purify the Fe₃O₄@CDs. The solution was freeze-dried to obtain the target product.

[0025] Furthermore, the dosage of the CDs-modified high-compatibility acceptor material was 50-100 mg / L by mass to the sludge volume in the reactor;

[0026] Furthermore, the Fe 2+ / Fe 3+ Dynamic concentrations and directions of succession in microbial communities.

[0027] Finally, the interfacial charge transfer process based on the conductive bridge modification promotes the expulsion of bio-ammonia electrons to activate Fe2+ / Fe 3+ The ANAMMOX system is a completely non-nitrite-dependent system that combines excellent effluent quality, long-term stability and environmental friendliness.

[0028] First, the nano-conductive filaments composed of CDs facilitate direct electrical contact between anammox bacteria and extracellular receptors (Fe3O4), providing excellent coulombic efficiency and competitive current output density in the absence of NO2. - Participation drives almost all NH4 + be removed;

[0029] Secondly, based on the efficient interfacial charge flux mediated by the “bridge”, Fe3O4 is also recognized by bioelectronics and further transduced into a reversible redox pair (Fe 2+ / Fe 3+ );

[0030] Furthermore, Fe 2+ The reducing power carried by the iron is directed to the associated bacteria through the iron oxidation metabolic pathway, promoting the biosynthesis of high-value chemicals or key cofactors, which helps to meet the subsequent metabolic needs of anammox and make up for the coenzyme deficiency. 2+ Reconverted to Fe 3+ ;

[0031] Finally, the oxidation signal Fe 3+ As an electron acceptor, it continuously improves the intensity of ammonia electron outflow, resulting in the conversion rate of electrical energy to chemical energy, accelerating the autotrophic growth of ANAMMOX.

[0032] The present invention provides a method for efficiently and stably operating a non-nitrite-dependent anaerobic ammonium oxidation process, which has the following technical effects:

[0033] 1. As a prerequisite for the activation of new redox communication, the present invention comprehensively improves the charge transfer flux at the bacterial material interface only through the "conductive bridge", easily achieving efficient and long-term treatment of ammonia-containing wastewater, reducing the high cost and complex operation and management of the traditional ANAMMOX process, greatly broadening the application scenarios and environmental benefits of the ANAMMOX process, and facilitating the direct implementation of single ANAMMOX in mainstream urban wastewater. In addition to the advantages of smooth and flexible operation, the non-nitrite-dependent ANAMMOX process also has other obvious process advantages. (1) No additional NO2 is required - Supply and NO3 - The discarding unit not only provides a feasible paradigm for the planning of space-compact sewage treatment plants, but also helps to alleviate the problem of ANAMMOX inactivation caused by species competition; (2) completely avoid the substrate required for N2O production and inhibit the oxidation of hydroxylamine (NH4 +→NH2OH+NO→N2O), nitrification and denitrification (NO2 - →NO→N2O) and heterotrophic denitrification (NO3 - →NO2 - →NO→N2O) occurs, and the greenhouse gas emission risk is negligible; in addition, (3) the ANAMMOX configuration that does not require oxygen and organic carbon minimizes energy consumption (O2) and effectively captures the original organic carbon in sewage for future bioenergy (i.e., fuels such as methane) recovery, which is expected to promote the transformation of sewage treatment plants from energy consumers to energy exporters.

[0034] 2. The redox communication strategy provided by this study creates an environment conducive to the proliferation of ANAMMOX bacteria. 2+ / Fe 3+ The redox cycle is expected to provide a convenient tool for close interspecies interactions between microorganisms and redistribution of cellular resources, thereby improving the carbon fixation efficiency and microbial proliferation rate of the autotrophic ANAMMOX system. Generally, microorganisms secrete communication molecules to sense the metabolic needs and product supply of surrounding companion bacteria, select partners in complex environments, and jointly cope with nutritional deficiency challenges. Therefore, a strong species communication method is the key to achieving effective sharing of interspecies metabolites. The iron oxidation / reduction state is reversibly switched through electron transfer between electroactive bacteria and companion species, avoiding the stagnation of the flow of information (i.e., cellular resources) within the microbial community; in addition, the bacterial redox potential is closely related to the extracellular redox substances (Fe 2+ / Fe 3+ ) ratio is also positively correlated, and the activity of functional enzymes with redox active functional groups is dynamically changed, thereby rebuilding and optimizing its metabolic network to improve the yield and quality of metabolites. 2+ / Fe 3+ The communication system not only has the ability to sense, analyze, and process interspecies information, but also coordinates microbial metabolic behavior to enhance interspecies metabolite exchange. On the one hand, accelerating the capture of inorganic carbon by ANAMMOX autotrophic bacteria provides a foundation for low-carbon emissions reduction and subsequent biomass synthesis, contributing to the future carbon-negative economy. On the other hand, the redox communication proposed in this invention paves the way for regulating biological systems with dynamic functions or behaviors, and opens the door to overcoming the problem of slow growth of ANAMMOX bacteria.

[0035] 3. Based on the macroscopic effects of efficient denitrification and long-term operation, the conductive bridge-mediated redox communication strategy provides a new approach for highly compatible, renewable and low-cost extracellular receptor materials, provides specifications and means to accelerate the self-assembly efficiency of the bio-nanomaterial interface, and has guiding significance for the future practical application and mechanism research of the non-nitrite-dependent ANAMMOX process. Take the Fe3O4@CDs used in Example 1 as an example. First, the surface of Fe3O4@CDs is easy to functionalize, and its surface properties can be adjusted by various chemical means to adapt to different water quality environments or reaction systems, so that Fe3O4@CDs can efficiently bind to various biomolecules or enzymes on the surface of ANAMMOX bacteria to form stable complexes. At the same time, the magnetic properties of Fe3O4@CDs also give the material the characteristics of easy separation and recovery, further enhancing its compatibility in biological denitrification systems. Secondly, the renewability of Fe3O4@CDs is mainly reflected in its stable chemical structure and good recycling performance. As a new type of carbon-based nanomaterial, CDs has excellent photostability and chemical inertness, can maintain structural integrity under various conditions, and is not easily degraded. Fe3O4, as the core, not only enhances the stability of the composite material but also provides it with good electron transfer capabilities, directly participating in the iron cycle in the redox network and promoting the continued progress of the reaction. Finally, from a cost perspective, the raw materials for the synthesis of Fe3O4@CDs are relatively abundant and easy to obtain, such as iron salts and carbon-containing precursors, and the raw material costs are relatively low. At the same time, the synthesis methods of Fe3O4@CDs are diverse and relatively simple, including hydrothermal and solvothermal methods. These methods are simple to operate and have mild conditions, which are conducive to large-scale production. Therefore, compared with some traditional precious metals or rare materials, Fe3O4@CDs has significant cost advantages and is more in line with the demand for low-cost extracellular receptor materials.

[0036] In summary, the interspecies redox communication method based on conductive bridges has completely broken through the diffusion flux limitation of ANAMMOX substrates in anaerobic environments and expanded the possibility of realizing mainstream ANAMMOX. The effective exchange of interspecies metabolites and the strong carbon capture potential improve the metabolic level of AnAOB itself and accelerate the process of cell self-replication. It is expected to break through the physiological limit of ANAMMOX enrichment and complete population expansion in a very short time, thereby cultivating non-nitrite-dependent ANAMMOX granular sludge with high bacterial density, greatly expanding the application breadth and treatment depth of the new process. Compared with other existing ANAMMOX optimization strategies, the use of permanent extracellular receptors to replace NO2 - It also reorganizes the anammox population interaction network and activates redox communication in situ to flexibly manage biomass concentration, making it more engineering-friendly and sustainable. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0038] Figure 1 This is a schematic diagram of the relative positions of ANAMMOX bacteria, conductive bridges, and extracellular receptors;

[0039] Figure 2 、 3 It is the long-term operating performance, carbon fixation and functional bacteria proliferation effect of the non-nitrite-dependent ANAMMOX system under the redox communication strategy. DETAILED DESCRIPTION

[0040] The following examples are provided for a better understanding of the present invention and are not intended to limit the best mode of implementation. They do not limit the content and scope of protection of the present invention. Any product identical or similar to the present invention obtained by anyone under the guidance of the present invention or by combining the features of the present invention with other prior arts shall fall within the scope of protection of the present invention.

[0041] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in this field can be used. If the manufacturer of the reagents or instruments is not specified, they are all commercially available conventional reagents.

[0042] Example 1

[0043] This embodiment provides an efficient and stable operation strategy for a non-nitrite-dependent anaerobic ammonium oxidation process, including an ANAMMOX acclimation and operation unit and an extracellular electron acceptor substance modification unit;

[0044] Specifically, the core reactor of the ANAMMOX acclimation and operation unit adopts a continuous flow operation mode. The reactor structure is provided with a water inlet at the bottom and a water outlet at the top;

[0045] The startup of the highly efficient and stable non-nitrite-dependent ANAMMOX process comprises the following steps:

[0046] First, build a stable traditional ANAMMOX system:

[0047] (1) Normal ANAMMOX sludge was used as inoculum sludge. In this embodiment, Candidatus Brocadia was identified as the dominant functional bacteria in the ANAMMOX sludge.

[0048] (2) Add the seed sludge into the reactor, and the volume of the seed sludge accounts for 20% of the total volume of the reactor. Use deionized water to prepare a solution containing 130mg / L NO2 - 、100mg / LNH4 + , 60mg / LCaCl2, 1000mg / LKHCO3 artificial wastewater, and keep the pH of artificial wastewater at 7.5. - / NH4 + The ratio is 1.3. The artificial wastewater was pumped into the reactor and stirred, resulting in an initial mixed solution with a total suspended solids content of approximately 3000 mg / L, a volatile suspended solids / total suspended solids (ρ(VSS) / ρ(SS)) ratio of 0.5, and an average sludge particle size of 800.6 μm. Sedimentation was then performed and the water discharged. The generation time of ANAMMOX was measured to be as long as 15-30 days.

[0049] Simultaneously, the extracellular electron acceptor is modified. In this embodiment, Fe3O4 nanopowder is preferably used as the extracellular electron acceptor and CDs are used as the conductive bridge.

[0050] The total nitrogen removal rate in the reactor effluent was higher than 85%, and the denitrification effect of the system reached a stable state.

[0051] In the extracellular electron acceptor substance modification unit:

[0052] (1) Dissolve ammonium ferric citrate (2.33 g) and ethylenediamine monohydrate (800 μL) in deionized water (20 mL) according to the ratio;

[0053] (2) The solution was transferred to a 40 ml Teflon-lined microwave digestion tank and irradiated at 800 W and 180°C for 10 min. The color of the solution changed from reddish brown to dark black brown, indicating that Fe3O4 and ethylenediamine-functionalized CDs were simultaneously carbonized and doped to produce Fe3O4@CDs. After the reaction, the reactor was cooled to room temperature.

[0054] (3) The obtained Fe3O4@CDs were centrifuged at 1600g for 10 min to precipitate the non-fluorescent aggregates.

[0055] (4) The supernatant was dialyzed using a 500Da dialysis membrane to harvest and purify Fe3O4@CDs. The solution was freeze-dried to obtain the target product.

[0056] Subsequently, the present invention added 100 mg / L of CDs-loaded modified [Fe3O4] nanopowder into the traditional ANAMMOX system based on culture to gradually reduce the influent NO2 - / NH4 + ratio, and construct an extracellular respiration ANAMMOX process that does not require nitrite in situ.

[0057] Finally, the constructed extracellular respiration type anaerobic ammonium oxidation reactor is used to treat the synthetic wastewater; in order to facilitate the monitoring of the pH value and DO content of the reaction, a pH and DO meter is also included, and the pH measuring probe and DO measuring probe of the pH and DO meter are set in the reactor, located in the ANAMMOX reaction area.

[0058] The NO2 in the influent and effluent of the reactor in Example 1 - NH4 + The content of AnAOB was detected day by day, and the dynamic concentration of redox signals, the direction of microbial population succession, carbon fixation efficiency and AnAOB growth rate were also measured.

[0059] Table 1. Pollutant concentrations in the inlet and outlet water of Fe3O4 / CDs-NAMMOX

[0060]

[0061]

[0062]

[0063]

[0064]

[0065]

[0066]

[0067] Through TEM images, the present invention clearly shows that carbon nanowires (CDs) span the gap between ANAMMOX bacteria and Fe3O4 particles, which are used for directional and high-speed electron transfer. Therefore, the conductive CDs promote direct electrical contact between ANAMMOX bacteria and extracellular receptors (Fe3O4), providing excellent coulombic efficiency (89.1%) and a competitive current output density of 6.86 mA cm -2 Based on high-efficiency EET, NH4 + Converted into NH2OH, N2H4 and N2 in sequence, bypassing NO2 at the source - , NO and NO3 - , N2O emissions dropped significantly from 0.32mg-N / L to 0.008mg-N / L, and the greenhouse gas emission risk was negligible. After Fe3O4@CDs catalysis, without the need for oxygen, organic carbon and NO2 - Drive up to 99.95% of NH4 +The environmental benefits it brings far exceed those of the currently widely recognized nitrification-denitrification, traditional short-cut nitrification / ANAMMOX, and short-cut denitrification / ANAMMOX.

[0068] According to the microbial population structure, ANAMMOX bacteria (Ca.Brocadia) and associated bacteria (Verrucomicrobiae) showed almost the same succession direction. Among them, Verrucomicrobiae has the ability to oxidize Fe 2+ The electron uptake function of Fe 2+ is converted back into Fe 3+ ; and Fe 3+ It continues to act as an electron acceptor to induce Ca.Brocadia to transfer extracellular electrons. Based on the dynamic conversion and utilization of bioelectrons between the electroactive microorganism Ca.Brocadia and the companion species Verrucomicrobiae, a friendly cooperative microbial community centered on ANAMMOX bacteria is formed. It is confirmed that the two have established a friendly cooperative microbial community centered on ANAMMOX bacteria through the redox communication strategy to maintain high efficiency (up to 99.97%) and sustainable (over 170 days) deamination in the non-nitrite-dependent system. In the present invention, the reducing Fe 2+ Stimulates CoA / CoR production in the associated bacteria Verrucomicrobiae, with a biomanufacturing yield far exceeding the traditional ANAMMOX system by 245%, supporting the integrity of the central carbon metabolism pathway and the metabolic activity of carboxylases in ANAMMOX bacteria through chemotactic migration and interspecies cross-feeding. 3+ This induced the overexpression of proteins related to electron gain (HZS and HDH) and electron transfer (cytochrome c), resulting in a 131% increase in the intracellular NADH, NADPH, and ATP levels in Ca. Brocadia. The metabolic costs required for the above-mentioned microbial synthesis were continuously and highly-densified into AMX1 to highlight the efficiency of functional microbial production. On the one hand, the non-nitrite-dependent ANAMMOX system HCO3 - The capture rate reached 4.32 mg / g·MLVSS·h, which is 1.77-fold that of the traditional ANAMMOX system, proving that the inorganic carbon fixation efficiency of AMX1 was effectively improved. Correspondingly, the HCOOH content in the non-nitrite-dependent ANAMMOX system increased from 0.25 mg / g·MLVSS to 0.58 mg / g·MLVSS. On the other hand, the ANAMMOX bacteria-specific functional gene HZS was quantified by qPCR, and its absolute copy number was also enriched from 110592.8 to 407221.4. Comprehensive HCO3 - Fixation rate, HCOOH production and marker gene enrichment were not available in the absence of soluble electron acceptor NO2 -In the environment, ANAMMOX bacteria still expanded from 16.32% to 34.67% in an unexpected generation time (only 2 / 3 of the theoretical time: 10.63 days), providing strong technical support and confidence guarantee for future engineering applications. It is important that Fe3O4 forms Fe between ANAMMOX bacteria and associated bacteria. 2+ / Fe 3+ Circulation ensures that Fe3O4@CDs can operate continuously and effectively in the bioreactor without repeated addition. Considering the market price of Fe3O4 (0.011RMB / g) and the dosage (0.5g / L), the operating cost of the new process is only 5RMB / m 3 And settle it all at once.

[0069] Example 2

[0070] This embodiment provides an efficient and stable operation strategy for a non-nitrite-dependent anaerobic ammonia oxidation process. The difference from Example 1 is that this embodiment uses an electrolytic cell configuration reactor for verification, and carbon felt is used as the electrode material and provides a grip for microbial attachment. Among them, ANAMMOX bacteria grow at a low potential anode for the release and capture of ammonia electrons. The electrons are transmitted through wires and stored at the cathode, and are further used by the electricity-demanding associated bacteria to grow at the cathode, thereby forming a redox communication network. In order to accelerate the effective capture of ammonia electrons by the anode, a layer of mobile carbon quantum dots (CDs) is attached to the anode surface by electrodeposition, rather than a fixed electron transfer bridge. After specifically receiving the biological charge, it migrates to the anode surface in a directionally and rapidly manner by electrostatic repulsion. To this end, the introduction of "free carbon quantum dots (CDs)" into the ANAMMOX bio-electrolytic cell anode interface is also expected to create a high-speed, short-distance and directional charge transfer process to stimulate redox communication, thereby driving efficient and long-lasting non-nitrite-dependent NH4 + In order to further verify the feasibility of the present invention in practical application, the NO3 - 、NO2 - NH4 + The contents were measured every 5 days, and the beneficial effects of redox communication on microbial population succession were evaluated.

[0071] Table 2. Pollutant concentrations in the inlet and outlet water of MEC / CDs-ANAMMOX

[0072]

[0073]

[0074] The experimental results of Example 2 show that under the extracellular respiration type ANAMMOX process, the average NO3 - 、NO2 -NH4 + The concentrations were 0.45 mg / L, 0 mg / L and 0 mg / L, respectively, meeting the Class A discharge standard for urban sewage. 2+ The concentration first increased and then decreased, and finally converted to 1.45±0.05mM Fe 2+ and 0.35 ± 0.05 mM Fe 3+ . Under the guidance of redox communication, microorganisms actively evolved to form a friendly microbial community dominated by AMX1 and VER2. The iron redox communication network also induces directional aggregation of bacteria with high biological affinity, compressing the distance between species to facilitate AMX1 to obtain defective factors (CoA / R) from VER2. Accordingly, the TPM value mapped by the AMX1 central biochemical conversion module (TCA cycle, gluconeogenesis and fatty acid synthesis) with CoA as the core increased by 110%; the expression activity of carbon conversion-related carboxylases (pyruvate carboxylase, acetyl-CoA carboxylase) with CoR as the main element was significantly upregulated. The enhanced carbon fixation efficiency and carbon metabolism enzyme cluster jointly promote the ANAMMOX bacteria in NO2 - In barren environments, the nitrogen removal rate was increased from 22.06% to 28.06% to maintain sustainable denitrification in a non-nitrite-dependent system, and the denitrification load was increased from 0.02 kg N / (m 3 ·day) increased to 0.26KgN / (m 3 ·day) and has been running stably for over 195 days.

[0075] Comparative Example 1

[0076] To confirm that the redox communication strategy mediated by the "conductive bridge" proposed in the present invention is the key to the efficient and long-term operation of the non-nitrite-dependent ANAMMOX system, Fe2O3 without "conductive bridge" modification was directly added to the ANAMMOX bioreactor, and the treatment performance of the normal system (1-45 days) and the modified system (45-75 days) was compared, as shown in Table 3. Compared with the normal "ANAMMOX" system, the extracellular electron acceptor lacking the "conductive bridge" cannot fully activate the extracellular respiratory potential of ANAMMOX. Even in the presence of NO2 - Under the operating conditions (ΔNO2- / ΔNH4 + is 1.0-1.2), its pollutant removal efficiency still dropped from 85.48% to 69.50%, and the biological denitrification system was facing collapse and could not meet the requirements of engineering operation.

[0077] Table 3. Pollutant concentrations in the inlet and outlet water of Fe2O3-ANAMMOX

[0078]

[0079] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A method for efficient and stable operation of a non-nitrite-dependent anaerobic ammonium oxidation process, characterized in that: Based on the mature anaerobic ammonium oxidation process, a highly compatible extracellular electron acceptor with a conductive bridge is introduced to establish a direct electrical connection between microorganisms and acceptor particles, activating redox communication in the microbial population and constructing a complete nitrite-independent anaerobic ammonium oxidation biological denitrification system. The conductive bridge not only enhances interfacial charge transfer flux for efficient pollutant removal, but also fosters a friendly and cooperative microbial population to maintain the long-term, stable operation of the nitrite-free system. The following steps are involved: Step 1. Build NO2 - and NH4 + Synchronously supplied anaerobic ammonium oxidation system: Put the inoculated sludge into the reactor, and then add the sewage into the reactor; the inoculated sludge must meet the following conditions: A. The volume of the inoculated sludge accounts for 30-50% of the total volume of the reactor; B. The total amount of suspended matter in the initial mixed solution formed after stirring is 2000-3000 mg / L; and the mass ratio of volatile suspended matter, i.e. biomass content / total suspended matter, is 0.3-0.5 to ensure that the added sludge has sufficient microbial population; The sewage in this step contains NO2 - NH4 + ;Among them, NH4 + The concentration is 40-80mg / L, NO2 - The configuration concentration is NH4 + The pH of the sewage was adjusted to 7.5-7.8 using 0.1-0.5M HCl or NaOH solution. Step 2: Add extracellular electron acceptor substances; the amount of the extracellular electron acceptor substances added is 50-100 mg / L by mass to the sludge volume in the reactor; and the influent NO2 is lowered every 3-4 days. - The mass concentration is 5-10mg / L until the influent NO2 - The mass is 0mg / L.

2. The method for efficient and stable operation of a non-nitrite-dependent anaerobic ammonium oxidation process according to claim 1, characterized in that: The extracellular electron acceptor substance has an electron vacancy on its surface and a reversible valence state, that is, its ion oxidation / reduction state is reversibly switched through electron transfer between electroactive bacteria and accompanying species. The types include but are not limited to ferric oxide (Fe2O3) nanoparticles, ferric oxide (Fe3O4) nanoparticles and electrodes that can produce hydrogen peroxide (H2O2) or hydrogen (H2).

3. The method for efficient and stable operation of a non-nitrite-dependent anaerobic ammonium oxidation process according to claim 1, characterized in that: The extracellular electron acceptor surface must possess a "bridge" for directional electron transfer routes in order to activate redox communication.

4. The method for efficient and stable operation of a non-nitrite-dependent anaerobic ammonium oxidation process according to claim 3, characterized in that: Fixed carbon nanowires with low resistance and mobile carbon quantum dots with charged shuttles are typical biological electron transfer "bridges" with a resistance of less than 30Ω.

5. A method for efficiently and stably operating a non-nitrite-dependent anaerobic ammonium oxidation process according to any one of claims 1 to 4, characterized in that: NH4 + The released electrons quickly reach the extracellular receptor surface through fixed or mobile conductive bridges, effectively improving the charge transfer flux at the bacterial interface and enhancing the pollutant removal efficiency of the non-nitrite-dependent anaerobic ammonium oxidation process.

6. The method for efficient and stable operation of a non-nitrite-dependent anaerobic ammonium oxidation process according to claim 5, characterized in that: Efficient electron flux drastically alters the charge and discharge properties of extracellular receptor particles to generate iron redox signals, which are used to gather friendly microbial communities centered around anaerobic ammonium-oxidizing bacteria.

7. The method for efficient and stable operation of a non-nitrite-dependent anaerobic ammonium oxidation process according to claim 6, characterized in that: Reduction signals select partners for anaerobic ammonium-oxidizing bacteria in complex environments and accelerate the production of high-value chemicals or key cofactors by associated bacteria, which helps to meet subsequent anaerobic ammonium-oxidizing metabolic needs and make up for coenzyme deficiencies. The reduction signals are re-transduced into oxidation signals.

8. The method for efficient and stable operation of a non-nitrite-dependent anaerobic ammonium oxidation process according to claim 7, characterized in that: The oxidation signal acts as an electron acceptor to continuously improve the intensity of ammonia electron outflow, resulting in the conversion rate of electrical energy to chemical energy and accelerating the autotrophic growth of anaerobic ammonia-oxidizing bacteria.

9. An efficient and stable non-nitrite dependent anaerobic ammonium oxidation process according to claims 7 and 8, characterized in that: The perfect metabolic pathway and energy production increase effect are jointly committed to the growth and reproduction of functional microorganisms to maintain the stable operation and durability of the non-nitrite anaerobic ammonia oxidation system.

10. The method for efficient and stable operation of a non-nitrite-dependent anaerobic ammonium oxidation process according to any one of claims 1 to 9, characterized in that: Interfacial charge transfer process based on conductive bridge modification promotes efflux of biological NH4 + Electrons are used to activate redox communication between microorganisms, thereby creating a complete non-nitrite-dependent anaerobic ammonium oxidation system that combines excellent effluent quality, long-term stability and environmental friendliness.

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