A method for strengthening an anammox sludge against starvation stress

Abstract

The present application relates to the field of microbial technology, and particularly relates to a method for strengthening resistance of anaerobic ammonia oxidation sludge to starvation stress. The method comprises adding hematite powder to a reactor containing the anaerobic ammonia oxidation sludge, and after starvation preservation treatment, the denitrification performance of the anaerobic ammonia oxidation sludge is restored. The present application provides suitable attachment sites for anaerobic ammonia oxidation microorganisms by the high density, surface adsorption sites and iron ion slow release of hematite powder, promotes the material and energy exchange between microbial cells and the external environment, strengthens the metabolic activity of microorganisms, accelerates the activity recovery, does not need to rely on complex and expensive equipment and noble metal catalysts, avoids the introduction of specific element dependence and secondary pollution risk, and is simple to operate, so that the activity recovery time of the anaerobic ammonia oxidation sludge after starvation stress is shortened in a low-cost, efficient and environmentally friendly manner.

Description

Technical Field

[0001] This invention relates to the field of microbial technology, and more specifically to a method for enhancing the resistance of anaerobic ammonia oxidation sludge to starvation stress. Background Technology

[0002] Anammox is an important pathway in the nitrogen cycle, converting nitrite into ammonium using nitrite as an electron acceptor, producing nitrogen gas and a small amount of nitrate as a byproduct under anaerobic conditions. Due to its advantages of low sludge production, low organic carbon demand, and low energy consumption, it has become a highly promising new biological nitrogen removal technology and has attracted much attention in the environmental field. However, Anammox technology faces challenges in its practical application to wastewater treatment. Anammox bacteria grow slowly and are easily inhibited by environmental factors such as extreme temperatures and substrate concentrations, resulting in slow reactor start-up. Although inoculating mature sludge can accelerate start-up, global strain resources are scarce, leading to insufficient supply of seed sludge for engineering applications. Furthermore, bacteria often face short-term or long-term starvation during wastewater treatment facility maintenance and sludge transportation and storage, resulting in reduced activity and utilization rates.

[0003] When Anammox bacteria encounter starvation (insufficient supply of ammonia and nitrite nitrogen), their metabolism is hindered and their activity decreases due to energy and nutrient depletion, resulting in a significant reduction in sludge utilization of the substrate. The prolonged recovery time is mainly due to two factors: First, Anammox bacteria grow slowly and have long generations. After being subjected to starvation stress, they need to resynthesize biomolecules and repair cell structure and function, involving gene expression regulation and metabolic pathway reconstruction. Laboratory recovery of activity can take weeks to months. Second, the recovery of Anammox denitrification performance is strictly constrained by environmental conditions such as temperature, pH, and dissolved oxygen, making it difficult to maintain stable levels in actual wastewater treatment. For example, low temperatures in winter inhibit enzyme activity and metabolic rates, and pH fluctuations also have a negative impact, further prolonging the recovery time.

[0004] Under prolonged starvation stress, sludge activity declines in multiple stages. Days 0-60 represent the "crash phase," where temperature drops from 30°C to 4°C and substrate is cut off, causing a sharp drop in sludge activity. Functional bacteria adapt to the low temperature by synthesizing cold-adaptation proteins, enhancing membrane fluidity (e.g., generating stepanes), and regulating metabolic enzyme systems. They rely on the hydrolysates of dead bacterial cells for energy, but some bacterial populations experience further activity reduction and even death due to lack of substrate supply. Days 60-150 represent the "maintenance phase," where surviving bacteria are nearly dormant, maintaining metabolism by decomposing stored energy and excess cellular components, resulting in stable sludge activity. Days 150-210 represent the "decline phase," where essential cellular components are metabolized for energy, excess components are depleted, cell function collapses, and activity continues to decline. Sludge delays activity loss and maintains the survival of functional bacteria through mechanisms such as low-temperature adaptation, dormant metabolism, and energy reserve utilization.

[0005] The recovery process of Anammox sludge activity under starvation conditions is time-consuming and faces numerous difficulties, which limits the widespread adoption of this technology. Sludge recovery involves four phases: cell lysis, lag phase, activity enhancement phase, and stationary phase. Cell lysis occurs when other bacteria gradually lose their competitive advantage in an environment suitable for Anammox bacterial growth. Subsequently, Anammox bacteria gradually adapt to the environment during the lag phase, achieve growth and reproduction during the activity enhancement phase, and finally reach a stationary state. Therefore, shortening the duration of these four phases and accelerating the growth process of Anammox bacteria are key to promoting rapid system recovery.

[0006] Currently, existing technologies mainly focus on cost-intensive methods, such as applying electric fields, using high-end bioreactors (such as membrane bioreactors and moving bed biofilm reactors), and adding expensive chemical catalysts (such as precious metal catalysts and specific enzyme preparations). These methods generally suffer from poor economic efficiency, complex operation, or the risk of heavy metal pollution, making it difficult to promote their application on a large scale in engineering. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a method for enhancing the resistance of anaerobic ammonia oxidation sludge to starvation stress. This invention utilizes the high density of hematite powder, its surface adsorption sites, and the slow release of iron ions to provide attachment sites for Anammox microorganisms, promoting the exchange of matter and energy between microbial cells and the external environment, enhancing microbial metabolic activity, and accelerating their activity recovery. This method eliminates the need for complex and expensive equipment (such as high-end bioreactors) and precious metal catalysts, avoiding the introduction of specific element dependence and secondary pollution risks. Furthermore, it is simple to operate, thus shortening the activity recovery time of Anammox sludge after starvation stress in a low-cost, efficient, and environmentally friendly manner.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The first objective of this invention is to provide a method for enhancing the resistance of anaerobic ammonia oxidation sludge to starvation stress, comprising the following steps: Hematite powder is added to the reactor containing the anammox sludge, and after starvation preservation treatment, the denitrification performance of the anammox sludge is restored; wherein the mass concentration of hematite powder in the mixture of anammox sludge and water matrix is ​​1 g / L to 2 g / L.

[0009] The conditions for starvation preservation are: storage at 2℃~6℃ for 0.5 to 1.5 years. Near-freezing temperatures can further inhibit the metabolic rate of microorganisms; however, temperature control is crucial to prevent freezing of water in the sludge due to excessively low temperatures, which could damage the cell structure of the anammox sludge. Conversely, excessively high temperatures accelerate microbial metabolism, leading to excessive nutrient consumption and cell senescence. Shorter preservation times may not meet the needs of some long-term research or practical applications, but at least 0.5 years of preservation ensures that microorganisms maintain activity in a relatively stable environment. Excessively long preservation times increase the risk of microbial activity loss and genetic variation. For anammox bacteria, prolonged starvation gradually depletes their intracellular metabolites, alters cell structure, and ultimately leads to reduced activity or even cell death.

[0010] Preferably, the mass concentration of hematite powder in the mixture of anaerobic ammonia oxidation sludge and water matrix is ​​1 g / L; and the nitrogen loading is 2 kg N / (m³). 3 When ·d), the ratio of hematite powder dosage to total nitrogen load is approximately 0.5 g / (gN·d), and this ratio range can be extended to cover different operating conditions. In practical applications, this ratio range provides operational flexibility, allowing for flexible adjustment of hematite powder dosage based on fluctuations in influent nitrogen load to ensure stable treatment results. At the same time, it takes into account economic efficiency, avoiding resource waste caused by excessive dosage while ensuring treatment efficiency, achieving a good balance between cost and effect.

[0011] Preferably, the starvation preservation treatment is performed at 4°C for one year. Differences in preservation time affect the effect of hematite powder on the recovery of denitrification performance of anammox sludge. When the preservation time exceeds one year, although hematite powder is still superior to the group without addition, the effect gradually weakens. This is because long-term preservation slows down microbial metabolic activity, alters the community structure, and reduces dependence on hematite powder. Furthermore, the activity of hematite powder decreases due to surface oxidation and particle aggregation, thus weakening its effect on promoting microbial metabolism and activity recovery. Conversely, when the preservation time is less than one year, the effect of hematite powder in shortening the recovery time is more significant. This is because at this time, the loss of microbial activity is minimal, cell structure and function are intact, and the relatively stable community structure results in high activity of dominant bacteria, accelerating the recovery of metabolic activity.

[0012] Preferably, the particle size of the hematite powder is 10μm~100μm.

[0013] Preferably, in the anaerobic ammonia oxidation sludge, the anaerobic ammonia oxidizing bacteria are... Candidatus Kuenenia .

[0014] Preferably, the relative abundance of anaerobic ammonia oxidation bacteria in the anaerobic ammonia oxidation sludge is 10.0%~20.0%.

[0015] Preferably, the reactor is an upflow anaerobic sludge bed reactor, comprising: a three-phase separator, which is connected in series with a gas collection bag and an effluent tank.

[0016] A constant temperature water bath insulation pipe is fixed to the three-phase separator. Several sampling ports are opened on the constant temperature water bath insulation pipe. The constant temperature water bath insulation pipe is filled with anaerobic ammonia oxidation granular sludge and hematite powder.

[0017] A sealed water inlet tank is connected to the constant temperature water bath insulation pipe, and a water inlet peristaltic pump is installed between the two.

[0018] Preferably, the hematite powder is added all at once from the top of the reactor.

[0019] Preferably, the effective volume of the reactor containing anammox sludge is 0.8L to 2.2L; wherein, the effective volume refers to the volume of anammox sludge, hematite powder and water matrix in the reactor.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention provides a method for enhancing the resistance of anammox sludge to starvation stress. Hematite powder is added to a reactor containing anammox sludge, and after starvation preservation treatment, an aqueous matrix is ​​added to the system to restore the sludge's denitrification performance. The mass concentration of hematite powder in the mixture of anammox sludge and aqueous matrix is ​​1 g / L to 2 g / L. The starvation preservation conditions are: storage at 2℃ to 6℃ for 0.5 to 1.5 years. Compared with cost-intensive methods involving applying an electric field, using advanced bioreactor technology, and adding expensive chemical catalysts, this invention, by adding exogenous hematite powder, more economically and conveniently accelerates the recovery of anammox sludge activity by retaining microorganisms, shortening cell proliferation time, and improving functional enzyme activity.

[0021] Among them, the high density and good settling properties of hematite powder can stabilize the anammox sludge system. Its high density allows it to settle quickly in the anammox sludge system, preventing the sludge from floating and maintaining a reasonable concentration distribution. Its good settling properties ensure the effective separation and accumulation of anammox sludge in the reactor, preventing loss and jointly maintaining the stable operation of the system. The abundant adsorption sites on the surface of hematite powder are closely connected to the anammox sludge particles. These sites can adsorb microorganisms, extracellular polymers, and particulate matter in the anammox sludge, providing attachment points for microbial aggregation, promoting mutual adhesion and aggregation of microorganisms, and gradually forming anammox sludge particles with stable structure and good settling performance. The iron ions released by hematite powder play a key role in the denitrification of anammox sludge. It is the active center or cofactor of many denitrification-related enzymes, which can activate the activity of enzymes in anammox sludge, accelerate nitrogen metabolism reactions, and participate in electron transfer processes, promoting the transformation of nitrogen elements and creating favorable conditions for the denitrification of anammox sludge.

[0022] Hematite powder, under starvation conditions, can provide an alternative electron transport pathway for bacteria in anaerobic ammonia oxidation sludge, alleviating energy metabolism limitations caused by substrate deficiency. Ferrous ions participate in the synthesis of cytochrome c and iron-sulfur proteins, helping to maintain the activity of key metabolic enzymes and enhancing the survival ability of bacteria under starvation stress. During the starvation recovery phase, hematite powder can promote bacterial metabolic activity and particle structure stability, accelerating the recovery of denitrification performance. Its surface redox reaction can rapidly activate the electron transport chain, restoring nitrite reduction and ammonia oxidation processes, while improving the particle physical structure of anaerobic ammonia oxidation sludge, enhancing its resistance to shock loads, and improving the system's denitrification efficiency and stability.

[0023] In addition, hematite powder accounts for about 70% of iron ore, and is abundant, inexpensive and easy to obtain, making it a promising candidate for use in anaerobic ammonia oxidation sludge systems.

[0024] 2. The method of using hematite powder to enhance the resistance of anammox sludge to starvation stress according to the present invention can improve the total nitrogen removal rate of anammox sludge. A nitrogen removal performance recovery experiment was conducted on sludge that had been starved at 4℃ for one year, with the initial influent load set at 0.25 kg·N / (m³). 3 (d). The results showed that during the starvation preservation process, the control group without hematite powder and the experimental group with hematite powder required 63 days and 8 days, respectively, to achieve a total nitrogen removal rate of 85%, indicating that the addition of hematite powder significantly accelerated the denitrification performance recovery process, increasing the recovery speed by 8 times.

[0025] 3. The addition of hematite powder can improve the microbial community diversity of Anammox sludge. After one year of starvation storage, the microbial community richness of the hematite group was higher than that of the control group, with Shannon indices of 4.02 and 3.94, respectively; and Simpson indices of 0.050 and 0.049, respectively. These data confirm that hematite powder enhances the stability and resistance to starvation stress of the system by maintaining microbial diversity. Attached Figure Description

[0026] Figure 1 The diagram shows the reactor, where 1 is a closed inlet tank, 2 is an inlet peristaltic pump, 3 is anaerobic ammonia oxidation granular sludge, 4 is hematite powder, 5 is a constant temperature water bath insulation pipe, 6 is a sampling port, 7 is a three-phase separator, 8 is a gas collection bag, and 9 is an outlet tank.

[0027] Figure 2 Diagram showing the microbial community composition (genus level) of anaerobic ammonia oxidation sludge inoculated with the sludge.

[0028] Figure 3 This is an X-ray diffraction pattern of hematite powder.

[0029] Figure 4 This is a graph showing the degradation of the water matrix during long-term operation.

[0030] Figure 5 This is a nitrogen load diagram for long-term operation.

[0031] Figure 6 The images show the morphology of the sludge after long-term operation. In the images, a is the control group, b is a magnified view of a, c is the hematite group, and d is a magnified view of c.

[0032] Figure 7 This is a graph showing the change in specific anaerobic ammonia oxidation activity during the denitrification performance recovery process. Detailed Implementation

[0033] The technical solution of the present invention will be clearly and completely described below with reference to the data in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0034] It should be noted that the technical terms used in this invention are only for describing specific embodiments and are not intended to limit the scope of protection of this invention. Unless otherwise specified, all raw materials, reagents, instruments and equipment used in the following embodiments of this invention can be purchased from the market or prepared by existing methods. Among them, the main phase composition of hematite powder is Fe2O3, which was purchased from Lingshou County Qingyi Mineral Products Processing Plant; sludge was obtained from Meixi Lake (Leifeng) Water Purification Plant, Xiangjiang New Area, Changsha City.

[0035] In existing technologies, the activity recovery of anaerobic ammonia oxidation sludge under starvation stress is slow, taking weeks to months, which severely restricts its engineering applications. Existing accelerated recovery methods (such as applying an electric field, using high-end bioreactors, or adding precious metal catalysts) can partially improve recovery efficiency, but they suffer from problems such as complex equipment, high cost, dependence on specific elements, or secondary pollution.

[0036] To address the problems existing in the prior art, this invention provides a method for enhancing the resistance of anammox sludge to starvation stress, comprising the following steps: adding hematite powder to a reactor containing anammox sludge, subjecting it to starvation preservation treatment, and then adding an aqueous matrix to the system to restore the sludge's denitrification performance; wherein the mass concentration of hematite powder in the mixture of anammox sludge and aqueous matrix is ​​1 g / L to 2 g / L; the starvation preservation treatment conditions are: storage at 2℃ to 6℃ for 0.5 years to 1.5 years.

[0037] To address the challenge of enhancing the activity and resistance to starvation stress of anaerobic ammonia-oxidizing bacteria for low-cost, high-efficiency denitrification, this invention utilizes the high density of hematite powder, its surface adsorption sites, and the slow release of iron ions to provide suitable attachment sites for anaerobic ammonia-oxidizing microorganisms. This promotes the exchange of matter and energy between microbial cells and the external environment, strengthens microbial metabolic activity, and accelerates their activity recovery. It eliminates the need for complex and expensive equipment (such as high-end bioreactors) and precious metal catalysts, avoiding the introduction of specific element dependence and secondary pollution risks. Furthermore, it is easy to operate, thus shortening the activity recovery time of anaerobic ammonia-oxidizing sludge after starvation stress in a low-cost, efficient, and environmentally friendly manner.

[0038] To enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments: The anaerobic ammonia oxidation reactor used in this invention is an upflow anaerobic sludge bed reactor with an effective volume of 2.2L. Its specific structure is as follows: Figure 1 As shown; the reactor is an upflow anaerobic sludge bed reactor, including: a three-phase separator 7, which is connected in series with the gas collection bag 8 and the effluent tank 9.

[0039] The constant temperature water bath insulation pipe 5 is fixed to the three-phase separator 7. The constant temperature water bath insulation pipe 5 has several sampling ports 6. The constant temperature water bath insulation pipe 5 is filled with anaerobic ammonia oxidation granular sludge 3 and hematite powder 4.

[0040] The sealed water inlet tank 1 is connected to the constant temperature water bath insulation pipe 5, and a water inlet peristaltic pump 2 is installed between the two.

[0041] Two reactors were set up for a comparative experiment: one reactor, designated as the experimental group, was treated with hematite powder; the other, designated as the control group, was treated without hematite powder. Both reactors were operated stably until the total nitrogen load reached 2.0 kg·N / (m³). 3 •d). Subsequently, the sludge in the reactor was placed in a 4°C cold storage environment for a one-year starvation preservation treatment. After one year, the starved sludge was taken out for a denitrification performance recovery experiment. The sludge was found to contain... Candidatus Kuenenia.

[0042] In this embodiment, the influent is artificially prepared, and hydrochloric acid is used to adjust the pH value of the influent to about 7.

[0043] Example 1 A method for enhancing the resistance of anaerobic ammonia oxidation sludge to starvation stress includes the following steps: Add 1g of hematite powder to a 1L reactor containing 1.2kg of anaerobic ammonia oxidation sludge, and then stabilize the reactor at 37℃ until the total nitrogen load reaches 2.0kg·N / (m³). 3 ·d) After the sludge concentration is 9.0 g·VSS / L, the anaerobic ammonia oxidation sludge in the reactor is placed in a cold storage environment at 4℃ for low-temperature starvation storage for one year.

[0044] Example 2 A method for enhancing the resistance of anaerobic ammonia oxidation sludge to starvation stress includes the following steps: 1.2 g of hematite powder was added to a 1 L reactor containing 1.2 kg of anaerobic ammonia oxidation sludge. The reactor was then operated stably at 37 °C until the total nitrogen load reached 2.0 kg N / (m³). 3 ·d) After the sludge concentration is 9.0 g·VSS / L, the anaerobic ammonia oxidation sludge in the reactor is placed in a cold storage environment at 4℃ for low-temperature starvation storage for one year.

[0045] Example 3 A method for enhancing the resistance of anaerobic ammonia oxidation sludge to starvation stress includes the following steps: 2g of hematite powder was added to a 1L reactor containing 1.2kg of anaerobic ammonia oxidation sludge, and the reactor was then operated stably until the total nitrogen load reached 2.0kg·N / (m³). 3 ·d) After the sludge concentration is 9.0 g·VSS / L, the anaerobic ammonia oxidation sludge in the reactor is placed in a cold storage environment at 4℃ for low-temperature starvation preservation for one year.

[0046] Comparative Example 1 A method for anaerobic ammonia oxidation sludge to resist starvation stress includes the following steps: The reactor containing 1.2 kg of anammox sludge was operated stably until the total nitrogen load reached 2.0 kg N / (m³). 3 ·d) After the sludge concentration is 9.0 g·VSS / L, the anaerobic ammonia oxidation sludge in the reactor is placed in a cold storage environment at 4℃ for low-temperature starvation preservation for one year.

[0047] Total nitrogen removal rate test: After preservation, the denitrification performance of the anammox sludge from Example 1 and Comparative Example 1 was restored at 30℃. This process was divided into three stages: performance enhancement, secondary starvation, and secondary starvation recovery. Specifically, during the starvation recovery process, a water matrix was introduced into the constant-temperature water bath insulation pipe of the reactor. The concentration of the water matrix and the hydraulic retention time were adjusted, and the initial influent load was set to 0.25 kg·N / (m³). 3 With the hydraulic retention time set at 9.8 h and the water matrix concentration at 400 mg / L, the total nitrogen load is 0.98 kg N / (m³). 3 •d) Gradually increase the total nitrogen load in the reactors of Example 1 and Comparative Example 1 to 2.0 kg N / (m³). 3 ·d), respectively denoted as the hematite group and the control group, and the operation plan is shown in Table 1.

[0048] The aqueous matrix consists of ammonium chloride, sodium nitrite, other components, and water; the mass concentrations of NH4Cl and NaNO2 are determined by the influent nitrogen load. + -N and NO2 -The -N mass ratio is 10:11; other components are soluble salts and trace elements; the soluble salts and their mass concentrations are: 3.5 g / L NaHCO3, 0.3 mg / L MgSO4·7H2O, 0.01 mg / L NaH2PO4, 0.0056 mg / L CaCl2·2H2O; the trace elements consist of a first trace element and a second trace element, and the volume concentrations of the first and second trace elements are the same, both being 1.25 mL / L; the first trace element and its mass concentrations are: 5.00 g / L EDTA and 5.00 g / L FeSO4; the second trace element consists of: 15 g / L EDTA, 0.43 g / L ZnSO4·7H2O, 0.24 g / L CoCl2·6H2O, 0.99 g / L MnCl2·4H2O, 0.25 g / L CuSO4·5H2O, and 0.22 g / L... Na2MoO4·2H2O, 0.19 g / L NiCl2·6H2O, 0.21 g / L Na2SeO4 and 0.014 g / L H3BO4·7H2O.

[0049] Table 1. Reactor Operation Plan The microbial community composition of the sludge inoculated in the Anammox reactor of this invention is as follows: Figure 2 As shown, the main Anammox bacterial group in the sludge used in this invention is Candidatus Kuenenia The relative abundance of hematite was 10.0%–20.0%. After being stored at 4°C for one year, its relative abundance in the hematite and control groups was 14.06% and 1.58%, respectively. This indicates that the addition of hematite powder can enrich or maintain the survival of this type of microorganism. It can stabilize the community structure by selectively enriching, optimizing the microenvironment, or providing metabolic advantages, thus providing ecological support for the application of hematite powder in microbial preservation and biogeochemical cycles.

[0050] Depend on Figure 3 The XRD pattern of the hematite powder was found to be consistent with the standard pattern, indicating that the crystal structure characteristics (including crystal system type, cell parameters, atomic occupancy and periodic arrangement) of the hematite powder used in this invention are completely consistent with the typical structure of hematite powder in the standard database, verifying its phase purity and crystal integrity, and eliminating the interference of allotropes or impurity phases.

[0051] Depend on Figure 4 and Figure 5 The results showed that the total nitrogen removal efficiency of the control group and the hematite group reached 85%, requiring 63 days and 8 days respectively. The nitrogen removal performance recovery rate of the hematite group was approximately 8 times higher than that of the control group. This further demonstrates that hematite powder can effectively resist long-term starvation stress and improve nitrogen removal efficiency.

[0052] Depend on Figure 6 The surface morphology of the sludge showed that after long-term starvation stress, the sludge in the control group was fragmented, while the sludge in the hematite group was intact. The addition of hematite powder helped maintain the integrity of the sludge morphology under long-term starvation stress and played a protective role in the sludge structure.

[0053] Depend on Figure 7 Activity tests on sludge showed that the sludge in the hematite group had higher activity after long-term starvation stress. After a second starvation, the addition of hematite powder (II) increased the anaerobic ammonium oxidation activity by 18.0%, indicating that hematite powder can enhance the sludge activity under long-term starvation stress, and the sludge still had higher anaerobic ammonium oxidation activity after a second starvation.

[0054] It should be noted that when numerical ranges are involved in this invention, it should be understood that both endpoints of each numerical range, as well as any value between the two endpoints, can be selected. Since the steps and methods used are the same as in the embodiments, preferred embodiments are described here to avoid redundancy. Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this invention.

Claims

1. A method for enhancing the resistance of anaerobic ammonia oxidation sludge to starvation stress, characterized in that, Includes the following steps: Hematite powder was added to a reactor containing anammox sludge, and after starvation preservation treatment, water matrix was added to the system to restore the denitrification performance of the anammox sludge. The mass concentration of hematite powder in the mixture of anaerobic ammonia oxidation sludge and water matrix is ​​1 g / L to 2 g / L. The conditions for starvation preservation are: storage at 2℃~6℃ for 0.5 to 1.5 years; The particle size of hematite powder is 10μm~100μm; The relative abundance of anammox bacteria in anammox sludge was 10.0%–20.0%. Anaerobic ammonia-oxidizing bacteria are Candidatus Kuenenia ; Hematite powder is added all at once.

2. The method for enhancing the resistance of anaerobic ammonia oxidation sludge to starvation stress according to claim 1, characterized in that, The mass concentration of hematite powder in the mixture of anaerobic ammonia oxidation sludge and water matrix is ​​1 g / L.

3. The method for enhancing the resistance of anaerobic ammonia oxidation sludge to starvation stress according to claim 1, characterized in that, The conditions for starvation preservation are: storage at 4°C for 1 year.

4. The method for enhancing the resistance of anaerobic ammonia oxidation sludge to starvation stress according to claim 1, characterized in that, The reactor is an upflow anaerobic sludge blanket reactor, comprising: Three-phase separator (7), which is connected in a through connection to the gas collection bag (8) and the water outlet bucket (9); A constant temperature water bath insulation pipe (5) is fixed to the three-phase separator (7). Several sampling ports (6) are opened on the constant temperature water bath insulation pipe (5). The constant temperature water bath insulation pipe (5) is filled with anaerobic ammonia oxidation granular sludge (3) and hematite powder (4). A closed-type water inlet tank (1) is connected to the constant temperature water bath insulation pipe (5), and a water inlet peristaltic pump (2) is installed between the two.

5. The method for enhancing the resistance of anaerobic ammonia oxidation sludge to starvation stress according to claim 1, characterized in that, Hematite powder is added all at once from the top of the reactor.

6. The method for enhancing the resistance of anaerobic ammonia oxidation sludge to starvation stress according to claim 4, characterized in that, The effective volume of the reactor containing anammox sludge is 0.8L~2.2L.

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