A method and device for domesticating the aerobic respiration mode of anaerobic ammonium-oxidizing bacteria

Abstract

The present invention provides a method and device for domesticating the aerobic respiration mode of anaerobic ammonium-oxidizing bacteria. The method comprises the following steps: (1) adding a photocatalyst to a reactor inoculated with anaerobic ammonium-oxidizing bacteria and operating stably, adjusting the emission light wavelength to excite photogenerated electrons, and constructing a photocatalyst-anammox complex; (2) applying oxygen to the sludge layer area in the reactor, gradually increasing the oxygen partial pressure to form an aerobic environment, synchronously and gradually decreasing the pH value of the wastewater, and adding Cu<supgt;2+< / supgt; ions to the wastewater to directionally stimulate the loading of the ccb3-type cytochrome c oxidase protein structure of anammox bacteria; (3) maintaining the aerobic environment, adjusting the pH value of the wastewater to rise, and completing the initiation of the anammox aerobic respiration mode. The aerobic respiration domestication method in the present invention can solve the sensitivity of anammox bacteria to environmental oxygen and can maintain high-efficiency denitrification performance in a high DO dissolved oxygen environment.

Description

Technical Field

[0001] The present invention belongs to the technical field of water treatment, and particularly relates to a method and device for domesticating the aerobic respiration mode of anaerobic ammonia-oxidizing bacteria. Background Art

[0002] As one of the important pollution factors causing water eutrophication, the current sewage nitrogen discharge exceeds the standard, and the large pollution load pressure puts forward higher requirements for the advanced nitrogen removal treatment of sewage. Anammox bacteria are of great significance to the global nitrogen cycle and can use NO2 - -N as an electron acceptor to directly oxidize NH4 + -N to N2, with a short nitrogen conversion process and no need for additional carbon source and aeration during the reaction. Therefore, compared with the traditional biological nitrogen removal process, the anaerobic ammonia oxidation (Anammox) process has attracted much attention as a new and efficient wastewater nitrogen removal method with energy conservation. However, Anammox bacteria are sensitive to the growth environment conditions, which is another important factor hindering the rapid startup and stable operation of the process in addition to the long doubling time of Anammox bacteria. Among them, the influence of oxygen on Anammox bacteria is particularly significant. Anammox bacteria are considered anaerobic bacteria, and their activity is inhibited at an oxygen saturation of 0.25-2%. At present, it is still difficult to completely achieve a strict anaerobic environment in the actual process operation, especially in the single-stage short-cut nitrification / anaerobic ammonia oxidation coupling system (PN / A) and the emerging bacteria-algae coupling system with Anammox as the core bacteria. Therefore, improving the oxygen tolerance of Anammox bacteria and alleviating the oxygen inhibition phenomenon of Anammox bacteria have become important topics for maintaining the stable and efficient operation of the process and further shortening the process startup time, which helps to promote the engineering process of the biological nitrogen removal process with Anammox bacteria as the core.

[0003] At present, many studies are committed to improving the oxygen inhibition phenomenon of anammox bacteria by blocking the intrusion of oxygen into anammox bacteria or alleviating the oxidative stress caused by oxygen. On the one hand, forming aerobic-anaerobic biofilms and sludge granules is an effective method to create an anaerobic environment for anammox bacteria, limit the entry of oxygen into anammox bacteria, and avoid its harmful effects. Some scholars have proposed cultivating aerobic biofilms rich in AOB outside the anammox biofilm to protect the anaerobic environment of anammox. This method has successfully achieved stable operation of the reactor at a relatively high DO concentration (1.51 - 4.03 mg / L). However, this method relies on the aerobic layer of AOB to block oxygen. AOB bacteria only have high metabolic activity in a micro-oxygen environment and are inhibited in a high DO environment, so it is impossible to completely avoid anammox bacteria being attacked by oxygen. On the other hand, some studies focus on exploring methods to alleviate anammox after oxygen intrusion. For example, using nano-zero-valent iron to alleviate the oxidative stress phenomenon of anammox after oxygen intrusion and achieve a rapid recovery of anammox activity. However, this alleviation method is only applicable to short-term and low-concentration oxygen shocks of anammox bacteria, and nano-zero-valent iron needs to be continuously added during the process to maintain the operation performance of the reactor, resulting in metal pollution of the reactor effluent while increasing economic investment. Based on this, to overcome the above technical defects, it is urgent to develop a new type of anammox bacteria oxygen tolerance improvement technology with a high oxygen tolerance threshold, environmental protection, and economy, while maintaining the high-efficiency nitrogen removal performance of the bacterial community. Summary of the Invention

[0004] The present invention solves the technical problem in the prior art that there is a lack of technology capable of effectively improving the oxygen tolerance of anammox bacteria and unable to solve the oxygen inhibition phenomenon of anammox bacteria for a long time and thoroughly. Furthermore, the present invention provides an aerobic respiration domestication method for anaerobic ammonia-oxidizing bacteria with a high oxygen tolerance threshold, which can fundamentally solve the sensitivity of anammox bacteria to environmental oxygen and maintain high-efficiency nitrogen removal performance in a high DO dissolved oxygen environment. The present invention also provides an aerobic respiration domestication device for anaerobic ammonia-oxidizing bacteria for implementing the aerobic respiration domestication method of anaerobic ammonia-oxidizing bacteria.

[0005] The technical solution adopted by the present invention to solve the above technical problems is as follows:

[0006] An aerobic respiration mode domestication method for anaerobic ammonia-oxidizing bacteria, comprising the following steps:

[0007] (1) Add a photocatalyst to a reactor inoculated with anaerobic ammonia-oxidizing bacteria and operating stably, apply light, and adjust the emission light wavelength based on the light absorption range of the photocatalytic material to excite photogenerated electrons, thereby constructing a photocatalyst-anammox complex;

[0008] (2) Maintain the light parameters in step (1); apply oxygen to the original anaerobic sludge layer area in the reactor, gradually increase the oxygen partial pressure in the sludge layer area within the dissolved oxygen range of 0.2 - 2 mg / L to form a microaerobic environment, synchronously and gradually reduce the pH value of the wastewater to slightly acidic, and add a Cu 2+ ion solution to directionally stimulate the expression of the cbb3-type cytochrome c oxidase gene and the protein structure loading of anammox bacteria;

[0009] (3) Keep the oxygen partial pressure in the sludge layer area greater than or equal to 2 mg / L to form an aerobic environment, adjust the pH value of the wastewater to return to the level in step (1), and the anammox aerobic respiration mode is successfully started.

[0010] The method for domesticating the anammox bacteria aerobic respiration mode includes the following steps:

[0011] (1) Add a photocatalyst to a reactor inoculated with anammox bacteria and operating stably, continuously apply light, adjust the emission light wavelength based on the light absorption range of the photocatalytic material to excite photo-generated electrons, and the light intensity is 100 - 200 mW / cm 2 , maintain the substrate composition and pH value of the reactor influent consistent with the wastewater in the reactor, operate the reactor until the total nitrogen removal rate TNRE is greater than or equal to 85%, and at the same time the specific anammox activity SAA increases by at least 5%, and successfully construct a photocatalyst - anammox complex;

[0012] (2) Enter the domestication stage of the anammox aerobic respiration mode. In this stage, maintain the light parameters in step (1), add Cu 2+ ions to the influent, and operate the reactor according to the dual-channel step-by-step - cyclic domestication mode. The dual-channel step-by-step - cyclic domestication mode is: in each cycle, apply oxygen to the sludge layer area in the reactor, gradually control the dissolved oxygen concentration gradient in the sludge layer area to increase from 0.2 mg / L to 2 mg / L, maintain the domestication environment in a microaerobic state, and synchronously and gradually regulate the pH gradient of the reactor influent to decrease from 7.5 to 6.7, and repeat the cycle multiple times until the aerobic respiration mode is constructed;

[0013] (3) Increase the oxygen partial pressure to an aerobic environment, that is, control the dissolved oxygen concentration in the reactor sludge layer area to be greater than or equal to 2 mg / L, and at the same time adjust the pH value of the wastewater to return to 7.5, continuously operate the reactor until the total nitrogen removal rate TNRE is greater than 95%, and the cbb3-type cytochrome c oxidase is detected, and the enzyme activity is at least 20% higher than that at the end of step (2), and the anammox aerobic respiration mode is successfully started.

[0014] The steps for inoculating the anaerobic ammonium oxidation bacteria in the reactor in step (1) and achieving stable operation are as follows: inoculate the well - operated anammox granular sludge from the laboratory into the reactor, use the synthetic wastewater containing nitrite nitrogen, ammonia nitrogen, inorganic salts and trace elements as the influent, maintain the temperature at 34.5 - 35.5 °C during the operation of the reactor, set the hydraulic retention time (HRT) to 4 - 6 h, adjust the influent pH value to 7.5, and operate the anammox reactor until the total nitrogen removal rate is stable above 80%, that is, the operation reaches stability.

[0015] When inoculating the anammox granular sludge into the reactor, the suspended and fixed concentration of the inoculated sludge mixture is 5.00 - 5.50 g / L, and the volume of the inoculated granular sludge accounts for 30% - 35% of the reactor volume.

[0016] The photocatalyst described in step (1) is one or more of TiO2 / CdS cadmium photocatalyst, g - C3N4 / TiO2 photocatalyst, and Ni:CdS photocatalyst.

[0017] The dosage of the photocatalyst in the influent is 150 - 200 mg / L.

[0018] The conditions for judging whether the aerobic respiration mode is constructed in step (2) are as follows: the dissolved oxygen concentration in the sludge layer area is significantly greater than the dissolved oxygen concentration in the effluent; and during one HRT period, the difference in the change of the dissolved oxygen concentration in the sludge layer area and the dissolved oxygen concentration in the effluent with time t is significant, that is, the significance p < 0.05; and the total nitrogen removal rate reaches 90%, and the cbb3 - type cytochrome c oxidase is detected in anammox.

[0019] The Cu 2+ ion source in step (2) is CuSO4·H2O, and the dosing concentration is 1.844 g / L.

[0020] When gradually increasing the dissolved oxygen concentration and synchronously and gradually decreasing the influent pH value in step (2), the maintenance time for each level is greater than or equal to 4 h, and the total duration of each cycle is greater than or equal to 20 h.

[0021] An anaerobic ammonium oxidation bacteria aerobic respiration mode domestication device includes: a water inlet bucket, a pH pre - regulation reactor, an anammox domestication reactor, and an oxygen delivery device arranged in sequence. A light energy supply system is installed in the anammox domestication reactor; the anammox domestication reactor adopts a UASB reactor; the oxygen delivery device is connected to the anammox domestication reactor.

[0022] The domestication method and device for the aerobic respiration mode of anaerobic ammonium-oxidizing bacteria according to the present invention form a new aerobic respiration mode of anaerobic ammonium-oxidizing bacteria. The functional main bodies of this mode include the "Cu(II) reduction center" NADH dehydrogenase, the "electron transport center" cb1 complex, and the "oxygen absorption main body" cbb3-type cytochrome c oxidase. The specific construction process of the mode follows the following three steps: First, the photocatalytic reaction stimulates the generation of photogenerated electron flow, which stimulates the cb1 complex to become the "electron transport center", thereby providing the ferrocytochrome c electron carrier for cytochrome c oxidase, promoting its gene expression, and becoming the environmental signal factor for the expression of cytochrome c oxidase genes. Subsequently, a specific oxygen partial pressure is applied to lock the activated oxidase type as the cbb3-type cytochrome c oxidase. Based on the difference in oxygen affinity of different types of cytochrome c oxidases, step-by-step and cyclic oxygen supply is adopted, and the dissolved oxygen concentration is limited in the micro-oxygen range to conform to the environmental condition preference for the activation of the cbb3-type cytochrome c oxidase, so as to directionally stimulate the cbb3-type cytochrome c oxidase to be the "oxygen absorption main body" of the anammox aerobic respiration mode. Finally, the pH is lowered to stimulate the NADH dehydrogenase to become the "Cu(II) reduction center", driving the loading and functional reconstruction of the Cu catalytic center of the cbb3-type cytochrome c oxidase, and successfully constructing a new aerobic respiration mode of anaerobic ammonium-oxidizing bacteria.

[0023] The present invention provides a domestication method for the aerobic respiration mode of anaerobic ammonium-oxidizing bacteria. Research shows that the oxygen inhibition behavior of anammox bacteria is reversible, and the metabolic activity of anammox bacteria can recover to the initial level within 5 - 37 h in a micro-oxygen environment; in addition, the oxygen tolerance ability of anammox bacteria will fluctuate with the changes of anammox bacterial species and living environments. For example, Ca. B. sinica can only tolerate 0 - 63 µM of O2, while the oxygen tolerance range of Ca. K. stuttgartiensis reaches 200 µM. At the same time, the oxygen tolerance ability of anammox bacteria in the marine environment is relatively weak. The above shows that the strict anaerobicity of anammox bacteria needs to be re-considered, and it may have potential oxygen tolerance or absorption functions. As is well known, the metabolic functions possessed by microorganisms depend on the functional proteases activated in their cells. For this, the terminal oxidases with strong oxygen conversion functions in prokaryotes are mainly divided into two major families: bd-type cytochrome oxidase and heme copper cytochrome c oxidase family (including type A, type B, and type C). Among them, cytochrome c oxidase is an important part of the respiratory chain, and its main function is to reduce O2 in the environment to H2O while creating a proton concentration gradient, which is a representative electron transport enzyme for cellular aerobic respiration. Compared with other terminal oxidases, the cbb3-type cytochrome c oxidase is generally considered to have the highest oxygen affinity, and its proton pump conversion rate is relatively high, and the proton pump stoichiometry is 0.5H + / e- Therefore, cbb3-type cytochrome c oxidase is the preferred one among biological terminal oxidases for efficient oxygen absorption and energy conservation. In addition, the cbb3-type cytochrome c oxidase (cbb3-type CcO) gene has been generally identified in anammox bacteria, so anammox bacteria have the aerobic respiration potential based on cbb3-type cytochrome c oxidase. Based on this, the further expression and translation of the cbb3-type cytochrome c oxidase gene in anammox bacteria can make it a powerful "organ" for intracellular scavenging of molecular oxygen, enabling anammox bacteria to have aerobic respiration function. However, as a high molecular weight and structurally complex membrane-bound protein, the synthesis, loading and functional modification processes of this enzyme are complex, which makes it impossible to effectively activate this enzyme in anammox bacteria by ordinary oxygen supply culture. The aerobic respiration domestication method for anaerobic ammonium-oxidizing bacteria in the present invention is a targeted activation strategy, which can fundamentally solve the sensitivity of anammox bacteria to environmental oxygen and maintain high-efficiency denitrification performance in a high DO dissolved oxygen environment.

[0024] The present invention combines a photocatalytic material with a microorganism. The photo-generated electrons generated by the photocatalyst absorbing light energy undergo a transition and enter the cell, serving as available reducing equivalents in biological metabolism and thus being utilized by electron-consuming enzymes to ultimately enhance the metabolic activity. The photo-generated electrons can targetedly regulate the expression pattern of biological genes and activate the target functional enzyme through the regulation of environmental conditions. In view of the fact that the functions of the aforementioned oxidases all require a large amount of electrons to complete the reduction of O2 to H2O, it can be reasonably inferred that for the anammox bacteria, a microorganism with a terminal oxidase gene, the use of photo-generated electrons can stimulate the further protein synthesis of its encoded gene. The inventors of the present invention have found that different oxidases have different selective preferences for oxygen partial pressure. Type A cytochrome c oxidase only exists under aerobic conditions, while cbb3-type oxidase can adapt to both microaerobic and aerobic conditions, and the microaerobic condition is more conducive to activating its gene expression. Therefore, to directionally activate cbb3-type cytochrome c under photocatalytic conditions, a domestication environment with a specific oxygen partial pressure condition can be set to achieve the directional transport of photo-generated electrons to cbb3-type cytochrome c oxidase.

[0025] In addition to activating the expression of the target oxidase gene in anammox bacteria, the functional reconstitution of the cbb3-type cytochrome c oxidase is the final step to enable it to perform the oxygen conversion function. Heme and Cu are important cofactors of the cbb3-type cytochrome c oxidase. Only when both cofactors are loaded onto the subunits can this terminal oxidase play a role in electron transfer and oxygen reduction. For the former, anammox bacteria are rich in heme intracellularly, creating favorable conditions for the activation of the cbb3-type cytochrome c oxidase. In this invention, the loading of Cu is achieved in an aerobic environment because under aerobic conditions, Cu (II) dominates in the environment, and the bacteria still need to reduce it to Cu (I) to complete this loading process. The inventors of this invention found through research that NADH dehydrogenase has the activity to reduce copper and can serve as a "Cu reduction center". The reduction of Cu (II) also depends on the reducing environment in the cytoplasm. Therefore, in this application, controlling the decrease of the pH gradient is beneficial, on the one hand, to create an intracellular reducing environment and stimulate NADH dehydrogenase to act as the "Cu reduction center" of the cbb3-type cytochrome c oxidase; at the same time, the appropriate decrease in pH can, to a certain extent, change the lipid composition of the cell and increase the content of anionic lipids, thereby promoting the functional reconstitution of the cbb3-type cytochrome c oxidase.

[0026] The advantages of the aerobic respiration domestication method and device for anaerobic ammonium-oxidizing bacteria according to the present invention are as follows:

[0027] (1) The aerobic respiration domestication method for anaerobic ammonium-oxidizing bacteria described in the present invention provides an innovative aerobic respiration mode for anaerobic ammonium-oxidizing bacteria. By coupling a photocatalytic material with anammox bacteria, while exciting photogenerated electrons and combining with an "oxygen partial pressure + pH" dual-channel regulation mode, a new aerobic respiration mode based on the cbb3-type cytochrome c oxidase is activated, achieving a complete shielding of the oxygen inhibition phenomenon in anammox bacteria and efficiently removing nitrogen in a high dissolved oxygen DO environment. The proposed domestication method and device for the aerobic respiration mode in the present invention completely relieve the current limitation of the oxygen concentration on the process operation stability in the anammox process, broaden the application scenarios of the process, and at the same time improve the nitrogen metabolism activity of anammox bacteria, achieving a more efficient sewage denitrification efficiency, and innovatively promoting the development of the biological denitrification technology with anammox as the core.

[0028] (2) The aerobic respiration acclimation method of anaerobic ammonium oxidizing bacteria described in the present invention establishes a new anaerobic ammonium oxidizing electron transport chain based on cbb3 type cytochrome c oxidase, and the anaerobic ammonium oxidizing aerobic respiration mode is activated. The present invention proposes that under the action of photogenerated electrons, a dual-channel step-by-step-cycle acclimation mode of "oxygen partial pressure + pH" is adopted to form a new anammox electron transport chain composed of "Cu(II) reduction center" NADH dehydrogenase, "electron transport center" cb1 complex, and "oxygen absorption body" cbb3 type cytochrome c oxidase, so that anammox abandons its strict anaerobic physiological characteristics and turns into an anaerobic microorganism, while being able to adapt to aerobic / anaerobic environments.

[0029] The anammox bacteria in the present invention have the following advantages based on the aerobic respiration mode of the new electron transport chain: 1) The oxygen sensitivity of traditional anammox bacteria is eliminated, which greatly promotes the stability of process operation and increases its application range. The present invention activates the aerobic respiration function of anammox bacteria through photocatalytic culture, and the cultured anammox sludge can maintain extremely high metabolic activity in both anaerobic and aerobic environments, broadens the working conditions applicable to the anaerobic ammonium oxidation process, and promotes its engineering development. 2) The new electron transport chain promotes energy conservation in the metabolism of anammox bacteria, promotes the growth of anaerobic ammonium oxidizing bacteria, shortens its doubling time to promote rapid start-up of the process. The new anammox electron transport chain based on cbb3 type cytochrome c oxidase incorporates oxygen into the category of available electron acceptors. At the same time, due to the high redox potential of oxygen, the reduced oxygen is synchronously coupled to protons to efficiently cross the membrane to enhance ATP generation. Therefore, the additional energy generated by the new electron transport chain can be used for energy-consuming metabolism such as carbon fixation and amino acid synthesis in the system, thereby promoting the accumulation of anammox biomass, shortening its doubling time, and helping to quickly start the process.

[0030] (3) The method for acclimating anaerobic ammonia-oxidizing bacteria to aerobic respiration of the present invention has high-efficiency denitrification performance based on the anammox aerobic respiration mode.

[0031] Firstly, the present invention introduces photogenerated electrons as the driving force for activating the aerobic respiration mode of anammox bacteria, wherein the cb1 complex acts as an "electron transport center" and the released ferrocytochrome c can also drive the hydrazine synthase (HZS) and nitrite reductase (NIR) of anammox nitrogen metabolism to promote denitrification.

[0032] Moreover, in the present invention, the electron transfer mode and enzyme structure of the cbb3-type cytochrome c oxidase are similar to those of the ammonia monooxygenase (AMO). The cbb3-type cytochrome c oxidase, also a membrane-bound protein, receives four electrons during catalysis to decompose one molecule of oxygen into two molecules of H2O. AMO and the cbb3-type CcO both belong to the copper-based binding proteins in the oxidase family and both have binuclear CuA binding sites in their protein structures. Based on this, the cbb3-type cytochrome c oxidase can be used as an alternative enzyme to AMO to perform the function of oxidizing ammonia nitrogen. Therefore, the activated anammox aerobic respiration mode of the present invention can simultaneously utilize HZS and the cbb-type cytochrome c oxidase for ammonia nitrogen absorption and finally generate N2 for removal.

[0033] The method for domesticating anammox bacteria for aerobic respiration according to the present invention can significantly reduce the limitation of nitrate by-products on the total nitrogen removal rate during the anammox process. On the one hand, photogenerated electrons can induce the activation of the function of reducing nitrate to ammonia (DNRA) in anammox bacteria, achieving partial removal of nitrate by-products in the system. On the other hand, the nitrate by-products of anammox bacteria are produced by the oxidation of nitrite by the NXR enzyme, thereby providing the reducing power required for carbon fixation in the system. For this, photogenerated electrons break the original electron closed-loop of anammox bacteria, that is, the WLP carbon fixation process tends to absorb photogenerated electrons with a lower redox potential as the driving force and discard the electrons provided by NXR, resulting in the inactivation of NXR and significantly reducing the generation of anammox nitrate by-products, thus enhancing the overall nitrogen removal efficiency of anammox bacteria.

[0034] Moreover, the nano-scale photocatalyst in the present invention combines with anammox bacteria to form a cellular "skeleton", significantly enhancing the mechanical strength of sludge particles and optimizing the sludge sedimentation performance. The photocatalyst used in the present invention is a solid crystal with uniform texture. Therefore, the nano-scale photocatalytic material with small particle size and large specific surface area is easy to combine with anammox bacteria and embed and coat in the sludge particles, finally forming a cellular "skeleton" of granular sludge, expanding the sludge particle size while enhancing the mechanical strength of the sludge particles and strengthening their sedimentation performance, which is beneficial to enhancing the shock resistance ability and denitrification stability of the sludge.

[0035] (4) The method for domesticating the anammox bacteria aerobic respiration mode according to the present invention is simple to operate, low in cost and environmentally friendly, and has the potential for industrialization. The present invention uses light energy as the only cultivation energy source and has sustainability.

[0036] (5) The method for domesticating the aerobic respiration mode of anaerobic ammonium-oxidizing bacteria according to the present invention proposes a novel cultivation method coupled with photocatalysis. The photocatalyst used has low cost and is environmentally friendly, and no by-products are generated during the cultivation process. The types of photocatalysts are preferably within the following categories: graphitic carbon nitride g-C3N4, titanium dioxide TiO2, cadmium sulfide CdS, which have stable photocatalytic activity, low cost, and are non-toxic and harmless. At the same time, in order to optimize the photoelectric separation effect of the photocatalyst to improve the efficiency of photogenerated electron release, the photocatalyst is specifically modified, and finally g-C3N4 / TiO with a heterostructure is preferably used. 2、 TiO2 / CdS and Ni:CdS are respectively prepared by hydrothermal synthesis method, sol–gel technique, and microwave-assisted heating method in the liquid phase method and stored in an argon bag for later use.

[0037] In order to make the technical solutions of the method and device for domesticating the aerobic respiration mode of anaerobic ammonium-oxidizing bacteria according to the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Description of the Drawings

[0038] Figure 1 is a schematic structural diagram of the device for domesticating the aerobic respiration mode of anaerobic ammonium-oxidizing bacteria according to the present invention;

[0039] Among them, the reference numerals are;

[0040] 1 - water inlet bucket; 2 - pH pre-regulation reactor; 3 - integrated control panel; 4 - real-time dissolved oxygen detector; 5 - full-spectrum light-emitting component; 6 - dissolved oxygen micro-probe; 7 - oxygen delivery device; 8 - high-purity oxygen tank; 9 - water outlet bucket; 10 - delivery pump. Specific Embodiments

[0041] The device for domesticating the aerobic respiration mode of anaerobic ammonium-oxidizing bacteria adopted in this embodiment is as Figure 1 shown, with a water inlet bucket 1, a pH pre-regulation reactor 2, and an anammox domestication reactor arranged in sequence. In the anammox domestication reactor, there is installed: a light energy supply system; an oxygen delivery device 7, which is connected to the anammox domestication reactor. The anammox domestication reactor adopts an upflow anaerobic sludge bed reactor, that is, a UASB reactor. In this embodiment, the effective volume of the anammox domestication reactor is 4.5 L. A dissolved oxygen analysis device is arranged outside the reactor, and multiple dissolved oxygen micro-probes 6 of the dissolved oxygen analysis device are located in the anammox domestication reactor. A delivery pump 10 is arranged on the pipeline between the pH pre-regulation reactor 2 and the anammox domestication reactor. The water outlet of the anammox domestication reactor is communicated with the water outlet bucket 9.

[0042] The oxygen delivery device 7 includes: a high-purity oxygen tank 8, a sensing gas valve, and an oxygen distributor. Among them, the high-purity oxygen tank 8 contains high-purity oxygen with a purity greater than or equal to 99.99%. The sensing gas valve is equipped with a real-time dissolved oxygen detector 4 and is connected to the integrated control panel 3, automatically regulating the opening and closing of the gas valve and the flow rate according to the target dissolved oxygen amount set by the integrated control panel 3; the oxygen distributor is installed at the bottom of the anammox domestication reactor, guiding oxygen from the supply pipeline into the reactor and evenly delivering the oxygen to the middle and lower parts of the reactor through nozzles, so as to keep the distributed oxygen evenly in the sludge area in the middle and lower parts of the reactor.

[0043] The light energy supply system mainly consists of an acrylic lamp shade and a full-spectrum light-emitting component. The full-spectrum light-emitting component is connected to the integrated control panel 3. The emission light wavelength of the full-spectrum light-emitting component can be controlled by the integrated control panel 3. The control panel calculates the optimal emission wavelength according to the light absorption range of the input photocatalytic material and sends an adjustment signal. The signal is transmitted to the light-emitting component through a micro cable to achieve the wavelength regulation of the light-emitting component.

[0044] A cylindrical light box is installed against the inner wall of the reactor. The light box consists of a full-spectrum light-emitting component and a transparent acrylic lamp shade, and the cross-section of the lamp shade is circular. The full-spectrum light-emitting components are evenly arranged in the lamp shade at intervals of 6 cm. The bottom of the lamp shade is closed and the outside is fixedly connected to the reactor through an acrylic bracket; at the same time, grooves are opened on the inner wall of the reactor and each groove evenly surrounds the inner wall of the reactor. The full-spectrum light-emitting components are also installed in the grooves, and the intervals between each groove are 10 cm.

[0045] The pH pre-regulation reactor includes an acid-base feeder, a water inlet tank, and a pH real-time measurement device. The pH regulation threshold of the reactor is set to the appropriate range of 6.7 - 8.3 for anammox metabolism. A pH real-time measurement device is set inside the reactor and is connected to the electromagnetic valve of the acid-base feeder. The electromagnetic valve is also connected to the integrated control panel. The opening and closing of the electromagnetic valve are controlled by both the pH real-time measurement device and the integrated control panel. Based on the target pH value set by the control panel and the real-time pH measurement value of the reactor, the opening and closing of the valve of the acid-base feeder are adjusted to adjust the pH of the influent water.

[0046] The following illustrates the domestication method of the aerobic respiration mode of anaerobic ammonia-oxidizing bacteria based on the above domestication device through specific examples. Example 1

[0047] First, complete the inoculation and stable operation of anaerobic ammonia-oxidizing bacteria in the anammox domestication reactor. The specific method is as follows:

[0048] Inoculate anammox sludge into an anammox domestication reactor. The suspended fixed concentration of the sludge mixture is about 5.50 g / L. Using simulated wastewater as the influent, the reactor operates at a temperature of 34.5 - 35.5 °C. The influent is adjusted to pH 7.5 via a pH pre-regulation reactor, and the hydraulic retention time is set to 6 h. The influent uses simulated wastewater, and the composition of the simulated wastewater is as follows: ammonia nitrogen 200 ± 5 mg·L -1 , nitrite nitrogen 200 ± 5 mg·L -1 , KHCO3 125 mg·L -1 , KH2PO4 54 mg·L -1 , EDTA 5 mg·L -1 and trace element solution I 2 mL·L -1 , trace element solution II 1 mL·L -1 , and the solvent is water.

[0049] Composition of trace element solution I: NaCl 500 mg·L -1 , KCl 700 mg·L -1 , CaCl2·2H2O 700 mg·L -1 , MgSO4·7H2O 500 mg·L -1 .

[0050] Composition of trace element solution II: CuSO4·5H2O 0.25 mg·L -1 , ZnSO4·7H2O 0.43 mg·L -1 , CoCl2·6H2O, 0.24 mg·L -1 , MnCl2·4H2O 0.99 mg·L -1 , NaMoO4·2H2O 0.22 mg·L -1 , NiCl2·6H2O, 0.19 mg·L -1 , NaSeO4 0.11 mg·L -1 , H3BO3 O.O14 mg·L -1 .

[0051] According to the above operation mode, keep the ratio of influent ammonia nitrogen to nitrite content at 1:1. Maintain this operation condition for a long time until the 7th day. The total nitrogen removal rate of the reactor is stable at 80%, completing the stable operation of the reactor. At this time, the reactor maintains an anaerobic state, and the dissolved oxygen concentration is close to zero.

[0052] Next, enter the aerobic respiration domestication stage of anaerobic ammonium oxidation bacteria. The specific method is as follows:

[0053] (1) Photocatalyst - anammox complex construction stage. During this stage, the operating parameters of the reactor were kept unchanged. TiO2 / CdS photocatalytic material with a dosage of 200 mg / L was added to the reactor with the influent water. This photocatalytic material was synthesized using the sol - gel technique. The specific synthesis process was as follows: Tetrabutyl titanate (TBOT) and cadmium sulfide (CdS) with a mass ratio of 1:1 (the masses were calculated based on TBOT and CdS respectively) were used and dissolved in ethanol to make the precursor solutions of TiO2 and CdS; the precursor solutions of TiO2 and CdS were ultrasonically mixed; an appropriate amount of hydrochloric acid (HCl) was added to the mixed precursor solution to trigger the sol - gel reaction and form a gel system; the obtained gel system was heat - treated to solidify the gel and form the crystal structure of the TiO2 / CdS composite material. Finally, the sample was dried to obtain the solid TiO2 / CdS composite material. The light energy supply system was started to emit visible light with a wavelength range of 400 - 540 nm according to the optoelectronic characteristics of TiO2 / CdS, so as to efficiently excite photogenerated electrons. The light - dark time ratio was set to 24 h:0 h, and the light intensity was 200 mW / cm 2 , and the influent substrate composition and pH were kept the same as those in the startup stage. This operation mode was maintained until the 14th day. The denitrification performance of the reactor was improved. The removal rates of ammonia nitrogen and nitrite increased by 2% and 3% respectively, and the total nitrogen removal rate increased to 85.78%. In addition, the specific anammox activity (SAA) continued to increase from the 7th to the 14th day, rising from 0.097 g N / g VSS / day to 0.152 g N / g VSS / day. The TiO2 / CdS - anammox complex was successfully constructed, and the anammox aerobic respiration mode domestication stage began.

[0054] (2) The light - related parameters in this stage were kept the same as those in the previous stage. CuSO4·H2O was added to the influent water at a dosage concentration of 1.844 g / L. The oxygen delivery device was started and the influent pH was pre - regulated. The reactor was continuously operated according to the "oxygen partial pressure + pH" dual - channel step - by - step - cyclic domestication mode. The dual - channel step - by - step - cyclic domestication mode was as follows: In each cycle, oxygen was applied to the sludge layer area in the reactor, and the dissolved oxygen concentration gradient in the sludge layer area was gradually controlled to increase from 0.2 mg / L to 2 mg / L, maintaining a domestication environment with a micro - aerobic state. At the same time, the pH gradient of the reactor influent was gradually regulated to decrease from 7.5 to 6.7. This was repeated in cycles until the aerobic respiration mode was constructed. The set parameters of the step - by - step domestication gradient for each cycle are shown in Table 1, and the maintenance time for each domestication gradient was set to 8 h.

[0055] Table 1 "Oxygen partial pressure + pH" dual - channel step - by - step - cyclic domestication mode

[0056] Gradient 1 2 3 4 5 DO content (mg / L) 0.2 0.8 1.2 1.6 2.0 pH value 7.5 7.3 7.1 6.9 6.7

[0057] The results showed that after 6 acclimation cycles, that is, on the 24th day of operation, the cbb3 cytochrome c oxidase was successfully detected by targeted protein detection technology, and during the 6th acclimation cycle, the effluent dissolved oxygen DO2 content was always maintained below 0.2 mg / L, and the growth rates of the dissolved oxygen concentration DO1 in the middle and lower mud layers and the effluent dissolved oxygen DO2 content with time t were significantly different, p<0.05, and the total nitrogen removal rate TNRE of the reactor reached 90%. At this point, the cbb3 cytochrome c oxidase-dependent aerobic respiration mode in anammox bacteria was successfully constructed.

[0058] (3) In order to stabilize the aerobic respiration mode and achieve high denitrification performance under high dissolved oxygen DO conditions, the influent pH was raised to 7.5, and the dissolved oxygen concentration DO1 in the lower mud layer of the reactor was further increased to 2 mg / L, and the DO1 content was increased by 4 mg / L every 6 hours. The reactor was continuously operated until the 30th day, when TNRE rose to 95%. At this time, cbb3 cytochrome c oxidase was detected by proteomics and was the most abundant electron transporter. The cbb3 cytochrome c oxidase kit detected that the enzyme activity was 32% higher than that at the end of step (2). In addition, the effluent dissolved oxygen DO2 concentration in this stage was always less than 0.3 mg / L, and the oxygen absorption rate was greater than 85%. The above proves that the anammox aerobic respiration mode has matured, and aerobic respiration anaerobic ammonium oxidation sludge with high denitrification performance has been successfully obtained.

[0059] In addition, after 30 days of acclimatization and cultivation, the average particle size of the TiO2 / CdS-anammox bacteria granular sludge formed increased by 178% compared with the seed sludge stage to about 680 mm; the sludge settling performance increased, and the SVI5 increased from 60.2±1.2 mL·g -1 SS decreased to 21.1±1.3mL·g -1 SS; at the same time, the anaerobic ammonia oxidation activity of the sludge was 3.12 times that of the seed sludge, which was 0.303 g N / g VSS / day. Example 2

[0060] The specific method for completing the inoculation and stable operation of anaerobic ammonia oxidizing bacteria in the anammox acclimation reactor in this embodiment is:

[0061] Anammox sludge was inoculated into the anammox acclimation reactor, and the sludge mixed liquor was suspended at a fixed concentration of about 5.50 g / L. Simulated wastewater was used as the influent. The reactor was operated at a temperature of 35±0.5℃. The influent was adjusted to 7.5 through the pH pre-control reactor, and the hydraulic retention time was set to 6h.

[0062] The influent was simulated wastewater, and the composition of the simulated wastewater was as follows: ammonia nitrogen 200±5mg·L -1, nitrite nitrogen 200 ± 5 mg·L -1 , KHCO3 125 mg·L -1 , KH2PO4 54 mg·L -1 , EDTA 5 mg·L -1 and trace element solution I 2 mL·L -1 、trace element solution II 1 mL·L -1 , the solvent is water.

[0063] Composition of trace element solution I: NaCl 500 mg·L -1 , KCl 700 mg·L -1 , CaCl2·2H2O 700 mg·L -1 , MgSO4·7H2O 500 mg·L -1 .

[0064] Composition of trace element solution II: CuSO4·5H2O 0.25 mg·L -1 , ZnSO4·7H2O 0.43 mg·L -1 , CoCl2·6H2O, 0.24 mg·L -1 , MnCl2·4H2O 0.99 mg·L -1 , NaMoO4·2H2O 0.22 mg·L -1 , NiCl2·6H2O, 0.19 mg·L -1 , NaSeO4 0.11 mg·L -1 , H3BO3 O.O14 mg·L -1 .

[0065] According to the above operation mode, keep the ratio of influent ammonia nitrogen to nitrite content at 1:1, and maintain this operating condition for 7 days. The total nitrogen removal rate of the reactor is stable at 80%, and the reactor operation is stable.

[0066] Next, enter the aerobic respiration domestication stage of anaerobic ammonium oxidation bacteria. The specific method is as follows:

[0067] (1) Photocatalyst-anammox complex construction stage. In this stage, the reactor operating parameters are kept unchanged, and 200 mg / L of nano-scale Ni:CdS photocatalytic material is added to the reactor along with the influent water. The material is prepared by microwave-assisted heating. The specific synthesis process is as follows: nickel chloride and cadmium sulfide are used as precursors, and ethanol is used as a reducing agent to prepare a reactant solution to promote the reduction reaction of nickel and cadmium sulfide; hexadecyltrimethylammonium bromide (CTAB) surfactant is added to the reactant solution to control the morphology and size of the synthesized nanomaterial; the reactant solution is placed in a microwave radiation reactor for irradiation reaction, and after naturally cooling to room temperature, the washed product is collected by centrifugation, and then freeze-dried and vacuum calcined to obtain Ni:CdS nanomaterial. The material is in a gray-yellow powder state. TEM, XRD and other characterization results show that the material structure morphology is a two-dimensional nanosheet, responds in the visible light range, and has good photocatalytic properties. The light energy supply system is started to emit 380-520nm visible light according to the photoelectric characteristics of Ni:CdS. Set the light-dark time ratio to 24h:0h and the light intensity to 200mW / cm 2 , and keep the influent matrix composition and pH consistent with the startup stage. Maintaining this operation mode until the 12th day, the total nitrogen removal rate increased to 87%. In addition, the anaerobic ammonia oxidation activity SAA continued to increase from 0.096 g N / g VSS / day to 0.188 g N / g VSS / day from the 9th to the 12th day, successfully constructing the Ni:CdS-anammox complex and entering the anammox aerobic respiration mode acclimation stage.

[0068] (2) During this stage, the same lighting parameters as in the previous stage were maintained. CuSO4·H2O was added to the influent at a dosage of 1.844 g / L. The oxygen delivery device was started and the influent pH was pre-regulated. The reactor was continuously operated according to the "oxygen partial pressure + pH" dual-channel stepwise-circulating acclimation mode. The dual-channel stepwise-circulating acclimation mode is as follows: In each cycle, oxygen was applied to the sludge layer area in the reactor, and the dissolved oxygen concentration gradient in the sludge layer area was gradually controlled to increase from 0.2 mg / L to 2 mg / L, maintaining an acclimation environment in a micro-aerobic state. At the same time, the pH gradient of the reactor influent was gradually regulated to decrease from 7.5 to 6.7. This was repeated in cycles until the aerobic respiration mode was successfully constructed; the setting parameters of the stepwise acclimation gradient for each cycle were the same as those in Table 1 of Example 1, and the maintenance time for each acclimation gradient was set to 6 h. The results showed that after 5 acclimation cycles, that is, when running to the 18th day, the cbb3-type cytochrome c oxidase was successfully detected by the targeted protein detection technology. During the 5th acclimation cycle, the dissolved oxygen in the effluent DO2 was always maintained below 0.2 mg / L. The growth rate differences of the dissolved oxygen concentration DO1 in the lower-middle sludge layer area of the reactor and the dissolved oxygen concentration DO2 in the effluent over time t were significant, p < 0.05. The total nitrogen removal rate TNRE of the reactor reached 90%. Thus, the cbb3-type cytochrome c oxidase-dependent aerobic respiration mode in anammox bacteria was successfully constructed.

[0069] (3) To stabilize this aerobic respiration mode and achieve high denitrification performance under a high DO state, the influent pH was raised back to 7.5, and the dissolved oxygen concentration DO1 in the lower-middle sludge layer area of the reactor was further increased to 2 mg / L, and the content of DO1 was increased by 4 mg / L every 4 h. The reactor was continuously operated until the 22nd day, and TNRE rose to 95%. At this time, the cbb3-type cytochrome c oxidase was detected by proteomics and was the most abundant electron transporter. The detection results of the specific enzyme activity kit showed that the activity of the cbb3-type cytochrome c oxidase increased by 48% compared with the end of step (2). The above proves that the anammox aerobic respiration mode tends to be mature, and aerobic respiration-type anaerobic ammonium oxidation sludge with high denitrification performance was successfully obtained.

[0070] In addition, after 22 days of acclimation and cultivation, the average particle size of the formed Ni:CdS-anammox granular sludge increased by 198% compared with the seed sludge stage, reaching about 720 mm; the sludge sedimentation performance improved, and SVI5 decreased from 659.88 ± 0.9 mL·g -1 SS to 19.74 ± 1.1 mL·g -1 SS; at the same time, the specific anaerobic ammonium oxidation activity of the sludge was 4.02 times that of the seed sludge, reaching 0.385 g N / g VSS / day.

[0071] Using Ni:CdS as a photocatalyst, aerobic respiration-type anaerobic ammonium oxidation sludge was successfully cultivated in 22 days, achieving a shorter cultivation time compared to TiO2 / CdS, having a stronger oxygen absorption capacity, and the denitrification performance of the cultivated sludge particles being better. Example 3

[0072] The specific method for inoculating and stably operating anaerobic ammonium oxidation bacteria in the anammox acclimation reactor in this example is as follows:

[0073] Inoculate anammox sludge in the anammox acclimation reactor, with the suspended fixed concentration of the sludge mixture being about 5.50 g / L. The water used in this example is the effluent after semi-nitrification of coal chemical wastewater and is typical secondary-treated effluent from coal chemical plants. The reactor is at a temperature of 35 ± 0.5 °C, the influent is adjusted to pH 7.5 through a pH pre-regulation reactor, and the hydraulic retention time is set to 6 h.

[0074] The original water quality composition of the wastewater is as follows:

[0075] 200 - 440 mg / L NO2 - -N, 206 - 385 mg / L NH4 + -N, 1.8 - 6.2 mg / L NO3 - -N, 485 - 513 mg / L COD, 30 - 45 mg / L TP, 4800 - 8750 mg / L salinity, 7 - 8 pH, 10 - 30 mg / L suspended solids (SS). The industrial wastewater is pretreated by filtration before entering, and most of the suspended solids are removed by filtration.

[0076] According to the above operation mode, maintain these operating conditions for a long time until the 15th day. The total nitrogen removal rate of the reactor is stable at 80%. At this point, the reactor operates stably and the anammox reactor starts successfully.

[0077] Next, enter the aerobic respiration acclimation stage of anaerobic ammonium oxidation bacteria. The specific method is as follows:

[0078] (1) Photocatalyst-anammox complex construction stage. In this stage, the reactor operating parameters were kept unchanged, and 200 mg / L of g-C3N4 / TiO2 photocatalytic material was added to the reactor along with the influent water. The specific synthesis method of the photocatalytic material was as follows: 4 g of melamine and 10 g of ammonium chloride were mixed and ground evenly, and the temperature was raised to 550°C in a muffle furnace at a heating rate of 1°C / min, and annealed for 2 hours to obtain yellow g-C3N4 nanosheets; 200 mg of g-C3N4 nanosheets were dispersed in 31.5 mL of isopropanol and ultrasonically dispersed for 30 minutes, 0.025 mL of diethylenetriamine (DETA) was added to the above solution, stirred for 10 minutes, and then 1.125 mL of diacetylacetonate diisopropoxy titanate solution was added, stirred evenly, and the mixed solution was transferred to the reactor and heat treated at 200°C for 24 hours. After the reactor was cooled to room temperature, the yellow precipitate was washed three times with deionized water and anhydrous ethanol respectively, dried in an oven at 60 °C for 24 hours, and finally annealed at 500 °C for 2 hours with a heating rate of 5 °C / min to obtain a g-C3N4 / TiO2 composite material. The light energy supply system was started to emit 300-450nm visible light according to the photoelectric characteristics of g-C3N4 / TiO2, thereby efficiently stimulating photogenerated electrons. The light-dark time ratio was set to 24h:0h and the light intensity was 200mW / cm 2 , and keep the influent matrix composition and pH consistent with the startup stage. Maintaining this operation mode until the 21st day, the denitrification performance of the reactor was improved, and the total nitrogen removal rate increased to 86.28%. In addition, the anaerobic ammonia oxidation activity (SAA) continued to increase from 0.089 g N / g VSS / day to 0.132 g N / g VSS / day from the 16th to the 21st day, and the g-C3N4 / TiO2-anammox complex was successfully constructed, and the anammox aerobic respiration mode acclimation stage began.

[0079] (2) During this stage, the same light parameters as in the previous stage were maintained. CuSO4·H2O was added to the influent at a dosage of 1.844 g / L. The oxygen delivery device was started and the influent pH was pre-regulated. The reactor was continuously operated according to the "oxygen partial pressure + pH" dual-channel stepwise-cyclic acclimation mode. The dual-channel stepwise-cyclic acclimation mode was as follows: In each cycle, oxygen was applied to the sludge layer area in the reactor, and the dissolved oxygen concentration gradient in the sludge layer area was gradually controlled to increase from 0.2 mg / L to 2 mg / L, maintaining an acclimation environment with a micro-aerobic state. At the same time, the pH gradient of the reactor influent was gradually regulated to decrease from 7.5 to 6.7. The cycle was repeated multiple times until the aerobic respiration mode was successfully constructed. The setting parameters of the stepwise acclimation gradient for each cycle were the same as those in Table 1 of Example 1, and the maintenance time for each acclimation gradient was set to 6 h. The results showed that after 8 acclimation cycles, that is, when running to the 34th day, the cbb3-type cytochrome c oxidase was successfully detected by the targeted protein detection technology. During the 8th acclimation cycle, the dissolved oxygen in the effluent DO2 was always maintained below 0.2 mg / L. The growth rate difference of the dissolved oxygen concentration DO1 in the middle and lower sludge layer areas of the reactor and the dissolved oxygen concentration DO2 in the effluent with time t was significant, p < 0.05. The total nitrogen removal rate of the reactor TNRE reached 90.66%. Thus, the cbb3-type cytochrome c oxidase-dependent aerobic respiration mode in anammox bacteria was successfully constructed.

[0080] (3) To stabilize this aerobic respiration mode and achieve high denitrification performance under high DO conditions, the influent pH was raised to 7.5, and the dissolved oxygen concentration DO1 in the middle and lower sludge layer areas of the reactor was further increased to 2 mg / L, and the content of DO1 was increased by 3 mg / L every 4 h. The reactor was continuously operated until the 40th day, and TNRE rose to 95%. At this time, the cbb3-type cytochrome c oxidase was detected by proteomics and was the most abundant electron transporter. The detection results of the specific enzyme activity kit showed that the activity of the cbb3-type cytochrome c oxidase increased by 28% compared with the end of step (2). The above proved that the anammox aerobic respiration mode tended to be mature, and aerobic respiration-type anaerobic ammonium oxidation sludge with high denitrification performance was successfully obtained.

[0081] In addition, after 40 days of acclimation and cultivation, the average particle size of the formed g-C3N4 / TiO2-anammox composite granular sludge increased by 163% compared with the seed sludge stage, reaching about 630 mm; the sludge sedimentation performance improved, and SVI5 decreased from 39.88 ± 0.3 mL·g -1 SS to 25.74 ± 0.8 mL·g -1 SS; at the same time, the specific anaerobic ammonium oxidation activity was 3.59 times that of the seed sludge, reaching 0.473 g N / gVSS / day.

[0082] Using g-C3N4 / TiO2 as a photocatalyst, aerobic respiration-type anaerobic ammonium oxidation sludge was successfully cultivated in coal chemical wastewater after 40 days of acclimation. This granular sludge has effective oxygen absorption capacity, can adapt to different oxygen concentration environments in actual sewage treatment, and at the same time, the nitrogen removal performance is greatly improved, achieving deep nitrogen removal from actual sewage. This proves that the method for acclimating anaerobic ammonium oxidation bacteria to aerobic respiration mode provided by the present invention has the application ability in actual engineering and is helpful for industrial development. Comparative Example 1

[0083] This comparative example was carried out simultaneously with the experiment of Example 1 and the experimental settings were basically the same. The main difference is that the photocatalyst TiO2 / CdS was not added during the acclimation stage of the aerobic respiration mode of anaerobic ammonium oxidation bacteria. Specifically as follows:

[0084] In the reactor startup stage, the inoculation, stable operation parameters and operation status of anaerobic ammonium oxidation bacteria in the anammox acclimation reactor were the same as those in Example 1, that is, until the 7th day of operation conditions, the total nitrogen removal rate of the reactor was stable at 80%, and the stable operation of the reactor was completed. At this time, the reactor maintained an anaerobic state and the dissolved oxygen concentration was close to zero.

[0085] Next, enter the acclimation stage of the aerobic respiration mode of anaerobic ammonium oxidation bacteria:

[0086] (1) Without photocatalyst coupling, the reactor continued to operate until the 14th day. Compared with Example 1, the nitrogen removal performance of the reactor was not significantly improved at this time, and the total nitrogen removal rate remained at 80%.

[0087] (2) With the same operating parameters as in Example 1, CuSO4·H2O was added to the influent at a dosing concentration of 1.844 g / L, the oxygen delivery device was started, and the influent pH was pre-regulated. The reactor was operated according to the "oxygen partial pressure + pH" dual-channel step-by-step - cyclic acclimation mode for 6 acclimation cycles. The results showed that by the 24th day of operation, the cbb3-type cytochrome c oxidase was not detected by the targeted protein detection technology. At the same time, the dissolved oxygen DO2 content in the effluent was basically the same as the dissolved oxygen concentration DO1 content in the middle and lower sludge layer areas during this period. In addition, the anaerobic ammonium oxidation bacteria were impacted by oxygen, the reactor performance deteriorated, the total nitrogen removal rate TNRE decreased to 74%, and the anaerobic ammonium oxidation activity SAA decreased by 20%. Based on this unsatisfactory experimental result, the verification of the aerobic environment with further increased oxygen partial pressure in the third stage was not carried out. The above experimental results show that without photocatalyst coupling, the aerobic respiration mode of anaerobic ammonium oxidation bacteria cannot be successfully acclimated and activated. Comparative Example 2

[0088] This comparative example was conducted simultaneously with the experiment in Example 1 and the experimental settings were basically the same, except that CuSO4·H2O was not added to assist the loading of the Cu catalytic center of the cbb3 type cytochrome c oxidase during the acclimation stage of the aerobic respiration mode of the anaerobic ammonia oxidizing bacteria. The specific experimental process and results are as follows:

[0089] During the reactor startup phase, the anaerobic ammonia-oxidizing bacteria inoculation and stable operating parameters and operating conditions in the anammox acclimation reactor were consistent with those in Example 1, that is, the total nitrogen removal rate of the reactor was stabilized at 80% until the 7th day of operation, completing the stable operation of the reactor. At this time, the reactor remained in an anaerobic state and the dissolved oxygen concentration was close to zero.

[0090] Next, we will enter the acclimatization stage of anaerobic ammonia oxidizing bacteria aerobic respiration mode:

[0091] (1) Photocatalyst-anammox complex construction stage. The operating parameters of this stage are consistent with those of Example 1. The experimental results also showed that the Ni:CdS-anammox complex was successfully constructed on the 14th day, which was reflected in the improved denitrification performance of the reactor, with the total nitrogen removal rate rising to 86.21%. The anaerobic ammonium oxidation activity (SAA) continued to increase from 0.095 g N / g VSS / day to 0.159 g N / g VSS / day from the 7th to the 14th day. At this point, the anammox aerobic respiration mode acclimation stage began.

[0092] (2) The illumination parameters of this stage were the same as those of the previous stage, the inlet composition remained unchanged, the oxygen delivery device was directly started and the inlet pH was pre-regulated, and the reactor was continuously operated according to the "oxygen partial pressure + pH" dual-channel step-by-step-cycle acclimation mode, in which the maintenance time of each acclimation gradient was set to 8 hours. The results showed that after 6 acclimation cycles (day 24), the targeted protein detection technology did not detect cbb3 type cytochrome c oxidase, and the effluent dissolved oxygen DO2 content decreased slightly compared with the DO1 content during the period. However, no significant difference was observed in the growth rate of the dissolved oxygen concentration DO1 and the effluent dissolved oxygen DO2 content with time t in the middle and lower mud layer area, p>0.05, and the total nitrogen removal rate TNRE of the reactor increased to 88.56%. Therefore, based on this experimental result, the cbb3 type cytochrome c oxidase-dependent aerobic respiration mode in anammox bacteria cannot be successfully constructed under the condition of Cu ion deficiency.

[0093] (3) The inlet pH was raised to 7.5, and the dissolved oxygen concentration DO1 in the lower mud layer of the reactor was further increased to 2 mg / L, and the DO1 content was increased by 4 mg / L every 6 hours. The reactor performance began to collapse on the 27th day, and TNRE continued to drop to 66%. At the same time, cbb3 type cytochrome c oxidase could not be detected. The above proves that the anammox aerobic respiration mode failed to be domesticated under the condition of Cu ion deficiency, and it could not operate stably in an aerobic environment. Comparative Example 3

[0094] This comparative example was conducted simultaneously with the experiment in Example 1 and the experimental settings were basically the same, the main difference being that the "oxygen partial pressure + pH" dual-channel step-by-step-cycle domestication mode was not used to activate the CBB3 type cytochrome c oxidase in the aerobic respiration mode of the anaerobic ammonia oxidizing bacteria. The specific experimental process and results are as follows:

[0095] During the reactor startup phase, the anaerobic ammonia-oxidizing bacteria inoculation and stable operating parameters and operating conditions in the anammox acclimation reactor were consistent with those in Example 1, that is, the total nitrogen removal rate of the reactor was stabilized at 80% until the 7th day of operation, completing the stable operation of the reactor. At this time, the reactor remained in an anaerobic state and the dissolved oxygen concentration was close to zero.

[0096] Next, we will enter the acclimatization stage of anaerobic ammonia oxidizing bacteria aerobic respiration mode:

[0097] (1) Photocatalyst-anammox complex construction stage. The operating parameters of this stage are consistent with those of Example 1. The experimental results also showed that the Ni:CdS-anammox complex was successfully constructed on the 14th day, which was reflected in the improved denitrification performance of the reactor, with the total nitrogen removal rate rising to 85.63%. The anaerobic ammonium oxidation activity (SAA) continued to increase from 0.099 g N / g VSS / day to 0.161 g N / g VSS / day from the 7th to the 14th day. At this point, the anammox aerobic respiration mode acclimation stage began.

[0098] (2) The lighting parameters of this stage were the same as those of the previous stage. CuSO4·H2O was added to the influent at a concentration of 1.844 g / L, and the reactor was operated continuously until the 24th day. The results showed that the total nitrogen removal rate TNRE decreased without significant changes during the period and remained at 85-86%. However, the targeted protein detection technology did not detect cbb3 type cytochrome c oxidase. At the same time, since the oxygen partial pressure was not increased, the oxygen concentration in the reactor environment was always maintained at an extremely low level, and the dissolved oxygen DO2 content of the effluent remained basically the same as the DO1 content during the period, and the oxygen absorption rate was almost 0. The above experimental results show that without adopting the "oxygen partial pressure + pH" dual-channel step-by-step-cycle acclimation mode, it is impossible to successfully acclimate and activate the aerobic respiration mode of anaerobic ammonia oxidizing bacteria.

[0099] (3) Increase the dissolved oxygen concentration DO1 in the middle and lower sludge layer area of the reactor to 2 mg / L, and increase the content of DO1 by 4 mg / L every 6 h. The performance of the reactor rapidly collapsed, the SAA dropped sharply to 0.034 g N / g VSS / day on the 26th day, the TNRE continued to decline to 32%, and at the same time, the cbb3-type cytochrome c oxidase could not be detected. The domestication of the anammox aerobic respiration mode failed, and the anaerobic ammonium-oxidizing bacteria could not survive in the aerobic environment.

[0100] The above-described embodiments merely represent several implementation manners of the present invention, and the description thereof is relatively specific and detailed. However, it should not be construed as a limitation to the scope of the patent for the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention shall be subject to the claims.

Claims

1. A method for domesticating the aerobic respiration mode of anaerobic ammonium-oxidizing bacteria, characterized in that, It includes the following steps: (1) Add a photocatalyst to a reactor inoculated with anaerobic ammonium-oxidizing bacteria and operating stably, apply light, adjust the emission light wavelength based on the light absorption range of the photocatalyst to excite photogenerated electrons, and construct a photocatalyst-anammox complex; (2)Enter the acclimation stage of anammox aerobic respiration mode. Maintain the light parameters in step (1) during this stage, and add Cu ions to the influent water. Operate the reactor according to the dual-channel step-by-step - cyclic acclimation mode. The dual-channel step-by-step - cyclic acclimation mode is as follows: In each cycle, apply oxygen to the sludge layer area in the reactor, and gradually control the dissolved oxygen concentration gradient in the sludge layer area to increase from 0.2 mg / L to 2 mg / L, maintaining an acclimation environment with a microaerobic state. At the same time, gradually regulate the pH gradient of the reactor influent to decrease from 7.5 to 6.7, directionally stimulating the expression of the cbb3-type cytochrome c oxidase gene and the protein structure loading of anammox bacteria. Repeat the cycle multiple times until the aerobic respiration mode is constructed. 2+ Ions, operate the reactor according to the dual-channel step-by-step - cyclic acclimation mode. The dual-channel step-by-step - cyclic acclimation mode is: in each cycle, apply oxygen to the sludge layer area in the reactor, and gradually control the dissolved oxygen concentration gradient in the sludge layer area to increase from 0.2 mg / L to 2 mg / L, maintaining an acclimation environment with a microaerobic state, and synchronously and gradually regulate the pH gradient of the reactor influent to decrease from 7.5 to 6.7, directionally stimulating the expression of the cbb3-type cytochrome c oxidase gene of anammox bacteria and the protein structure loading. Repeat the cycle multiple times until the aerobic respiration mode is constructed. (3) Control the dissolved oxygen concentration in the sludge layer area of the reactor to be greater than or equal to 2 mg / L to form an aerobic environment. At the same time, adjust the pH value of the wastewater to rise back to 7.5, continuously operate the reactor until the total nitrogen removal rate TNRE is greater than 95%, and the cbb3-type cytochrome c oxidase is detected, and the enzyme activity is at least 20% higher than that at the end of step (2), and the anammox aerobic respiration mode is successfully started.

2. The aerobic respiration mode domestication method of anaerobic ammonia-oxidizing bacteria according to claim 1, wherein In step (1), a photocatalyst is added to a reactor inoculated with anaerobic ammonium-oxidizing bacteria and operating stably, light is continuously applied, the emission light wavelength is adjusted based on the light absorption range of the photocatalyst to excite photogenerated electrons, and the light intensity is 100 - 200 mW / cm 2 , maintaining the substrate composition and pH value of the reactor influent unchanged, operating the reactor until the total nitrogen removal rate TNRE is greater than or equal to 85%, and at the same time the anaerobic ammonium-oxidizing activity SAA increases by at least 5%, successfully constructing a photocatalyst - anammox complex.

3. The aerobic respiration mode domestication method of anaerobic ammonia-oxidizing bacteria according to claim 2, characterized in that, The steps for inoculating the anaerobic ammonium-oxidizing bacteria into the reactor in step (1) and achieving stable operation are as follows: Inoculate well-operated anammox granular sludge from the laboratory into the reactor, use synthetic wastewater containing nitrite nitrogen, ammonia nitrogen, inorganic salts and trace elements as the influent. During the operation of the reactor, the temperature is maintained at 34.5 - 35.5 °C, the hydraulic retention time HRT is set to 4 - 6 h, the influent pH value is adjusted to 7.5, and the anammox reactor is operated until the total nitrogen removal rate is stable above 80%, that is, stable operation is achieved.

4. The aerobic respiration mode domestication method of anaerobic ammonia-oxidizing bacteria according to claim 3, characterized in that, When inoculating the anammox granular sludge into the reactor, the suspended and fixed concentration of the inoculated sludge mixture is 5.00 - 5.50 g / L, and the volume of the inoculated granular sludge accounts for 30% - 35% of the reactor volume.

5. The aerobic respiration mode domestication method of anaerobic ammonium-oxidizing bacteria according to any one of claims 1-4, characterized in that, The photocatalyst in step (1) is one or more of TiO2 / CdS photocatalyst, g-C3N4 / TiO2 photocatalyst, and Ni:CdS photocatalyst.

6. The aerobic respiration mode domestication method of anaerobic ammonia-oxidizing bacteria according to claim 5, characterized in that, The dosage of the photocatalyst in the influent is 150 - 200 mg / L.

7. The aerobic respiration mode domestication method of anaerobic ammonia-oxidizing bacteria according to claim 6, characterized in that, The conditions for judging whether the aerobic respiration mode is successfully constructed in step (2) are as follows: The dissolved oxygen concentration in the sludge layer area is significantly greater than the dissolved oxygen concentration in the effluent; and during one HRT period, the difference in the change of the dissolved oxygen concentration in the sludge layer area and the dissolved oxygen concentration in the effluent with time t is significant, that is, the significance p < 0.05; and the total nitrogen removal rate reaches 90%, and the cbb3-type cytochrome c oxidase is detected in anammox.

8. The aerobic respiration mode domestication method of anaerobic ammonia-oxidizing bacteria according to claim 7, characterized in that The Cu added to the influent water in step (2) 2+ The ion source is CuSO4·H2O, and the dosing concentration is 1.844 g / L.

9. The aerobic respiration mode domestication method of anaerobic ammonium-oxidizing bacteria according to claim 8, characterized in that, When gradually increasing the dissolved oxygen concentration and synchronously and gradually decreasing the influent pH value in step (2), the maintenance time for each level is greater than or equal to 4 h, and the total duration of each cycle is greater than or equal to 20 h.

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