Adjustable flora structure for short-cut nitrification and application thereof

Abstract

The present application relates to sewage treatment technical field, the present application provides a kind of composition for adjusting bacterial flora structure to realize short-cut nitrification, including the mass ratio of cyclodextrin and hydroxylamine acetate 1∶(10-20).The pharmaceutical agent comprising the composition and the application in short-cut nitrification related sewage biological treatment are also provided.The concentration of NH2OH in bacterial agglutinate can be effectively improved by the action of cyclodextrin and hydroxylamine acetate in the present application, the inhibition efficiency of NH2OH to NOB is enhanced, and the strengthening effect on AOB is enhanced, the bacterial flora structure is quickly adjusted, the stability of NO2 ‑ -N accumulation is improved, and the long-term stable operation of various short-cut nitrification related sewage biological treatment processes is laid foundation.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to a composition for achieving short-cut nitrification by adjusting the microbial community structure and its application. Background Technology

[0002] Nitrogen pollution in water bodies remains a serious problem, with eutrophication caused by excessive nitrogen discharge becoming increasingly prominent. In the development and upgrading of wastewater treatment technologies, short-cut nitrification-based denitrification processes offer numerous advantages, including reduced oxygen supply and energy consumption, decreased carbon source usage and material consumption, and reduced sludge production and treatment costs. However, achieving rapid and stable short-cut nitrification remains a key focus and challenge in the upgrading and transformation of current wastewater treatment processes.

[0003] Existing patent CN117945545A discloses a method and apparatus for treating wastewater based on short-cut nitrification, which utilizes sulfide treatment of sludge to induce the establishment of a short-cut nitrification system. CN118515364A discloses a nitrification method and wastewater treatment system with side-flow enrichment / mainstream enhancement of AOB, using anaerobic digestion supernatant of sludge as the influent to the side-flow short-cut nitrification reactor, controlling the dissolved oxygen concentration at 0.1–0.5 mg / L, pH at 8.50–8.54, and temperature at 30–37℃; daily, nitrite-treated sludge is taken from the side-flow short-cut nitrification reactor and added to the mainstream nitrification reactor, with the added nitrite-treated sludge accounting for 1.0–2.05% of the total sludge mass in the mainstream nitrification reactor, in order to enhance the nitrification capacity of the mainstream nitrification reactor. CN118084188A discloses a method for accelerating short-cut nitrification start-up through sludge pretreatment. The method includes: (1) pretreating activated sludge in a biological reactor for 1-20 days in the presence of low-ammonia-nitrogen water to obtain starved sludge; wherein the ammonia-nitrogen concentration of the low-ammonia-nitrogen water is 0-10 mg / L; and controlling the dissolved oxygen concentration of the pretreated water to be 0-4 mg / L; (2) contacting the ammonia-nitrogen wastewater with the starved sludge for short-cut nitrification to obtain effluent. In summary, these methods for achieving short-cut nitrification all require additional structures, and the start-up time for short-cut nitrification is long.

[0004] Furthermore, according to the literature "Research Progress on Influencing Factors and Enhancement Methods of Short-cut Nitrification," short-cut nitrification can be controlled and achieved by adjusting and optimizing operating parameters such as DO, aeration mode, pH, alkalinity, FA, FNA, and C / N ratio. However, problems still exist, including slow start-up, poor long-term operational stability, weak resistance to shock loads, and even issues such as filamentous bulking and sludge loss. Therefore, it is necessary to develop a short-cut nitrification control method that combines convenience, speed, and stability.

[0005] CN112390361B discloses a method for deep denitrification of domestic sewage using an integrated PNA SBBR process enhanced with hydroxylamine and ferrous ions. Adding hydroxylamine during the aerobic aeration stage effectively inhibits nitrite-oxidizing bacteria (NOB), rapidly achieving and stably maintaining short-cut nitrification of urban domestic sewage. Adding ferrous ions during the anoxic stirring stage promotes the enrichment of Anammox bacteria in the system, increasing their activity. However, hydroxylamine is an unstable inorganic substance that can undergo thermal decomposition, breaking down into ammonia, nitrogen, water, nitrogen oxides, etc.

[0006] Under alkaline conditions:

[0007] 3NH2OH→NH3+N2+3H2O-192.0kJ / mol(1)

[0008] Under acidic conditions:

[0009] 4NH2OH→N2O+2NH3+3H2O-138.9kJ / mol (2)

[0010] CN115595217B describes a method of encapsulating hydroxylamine molecules with cucurbitacin and its derivatives to prevent direct contact between hydroxylamine molecules and metal ions or acidic / alkaline media; using chelating agents to complex metal ions to ensure that hydroxylamine molecules released from cucurbitacin and its derivatives do not decompose due to catalysis by metal ions. This method also prevents hydroxylamine decomposition caused by high temperatures and alkalinity, making it widely applicable to semiconductor cleaning. However, encapsulating hydroxylamine within cucurbitacin reduces its efficiency in short-cut nitrification start-up processes. This is because hydroxylamine can only effectively inhibit NOB activity when it is in full contact with NOB. Cucurbitacin is a special cyclic molecule composed of eight interconnected urea groups (urea groups), which has poor water solubility. Therefore, this method cannot be directly applied to microbial water treatment, nor can it achieve rapid adjustment of the bacterial community structure to achieve short-cut nitrification. Furthermore, due to the poor biodegradability of cucurbitacin, its application in water treatment can lead to excessive nitrogen levels in the effluent.

[0011] In addition, hydroxylamine can not only decompose, but also undergo non-biological reactions with other substances in wastewater, such as:

[0012] NH2OH + HNO2 → N2O + 2H2O (3)

[0013] 2NH₂OH + 2MnO₂ + 4H⁺ → NO + 2Mn 2+ +5H2O(4)

[0014] In abiotic pathways, the reaction of NH2OH with HNO2 is the primary pathway for N2O production, followed by Fe reduction of HNO2 and Fe oxidation of NH2OH. These pathways are significantly influenced by pH and substrate concentration, and are particularly affected by acidic conditions and high NO levels. 2-Under certain conditions, the production of N2O will increase, which not only reduces the inhibition efficiency of NH2OH on NOB, but also increases the emission of greenhouse gases from the denitrification reactor. This will severely limit the ability to rapidly regulate the microbial community structure and achieve short-cut nitrification through NH2OH in industrial wastewater treatment.

[0015] Therefore, the key to improving the efficiency of microbial community structure regulation lies in how to more effectively apply hydroxylamine agents to NOB inhibition and reduce the consumption of hydroxylamine due to abiotic activities when achieving short-cut nitrification. Summary of the Invention

[0016] The purpose of this invention is to provide a composition that can adjust the microbial community structure to achieve short-cut nitrification and its application in the biological treatment of short-cut nitrification-related wastewater. Through the interaction of cyclodextrin and hydroxylamine acetate, the concentration of NH2OH inside the bacterial flocs can be effectively increased, enhancing the inhibition efficiency of NH2OH against NOB and improving the system's NO2 concentration. - The stability and efficiency of -N accumulation lay the foundation for the long-term stable operation of various short-cut nitrification-related biological wastewater treatment processes.

[0017] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0018] The present invention provides a composition for achieving short-range nitrification by adjusting the microbial community structure, comprising cyclodextrin and hydroxylamine acetate in a mass ratio of 1:(8-20).

[0019] Preferably, the cyclodextrin is α-cyclodextrin, β-cyclodextrin, or γ-cyclodextrin.

[0020] The present invention provides a pharmaceutical preparation comprising the composition.

[0021] The present invention also provides the application of the said composition or agent in the biological treatment of short-cut nitrification-related wastewater.

[0022] Preferably, during use, the composition or agent is directly added to the dosing area, and the concentration of the composition or agent in the dosing area is maintained at 1-10 mg / L (nitrogen value), and the pH of the dosing area is maintained at 6.5-8.5.

[0023] Preferred methods of delivery include using a sequencing batch reactor or a continuous flow reactor;

[0024] Preferably, when using a sequencing batch reactor, the dosing interval of the composition or reagent is 0.5 to 2.0 times the hydraulic residence time; when using a continuous flow reactor, the duration of each dosing of the composition or reagent is 1.0 to 3.0 times the hydraulic residence time.

[0025] Preferably, the sludge concentration in the addition area is 1000 mg / L to 10000 mg / L.

[0026] Preferably, when the nitrite accumulation rate in the addition area is 80-95%, the dosage of the composition or agent is reduced by 20%-60%; when the nitrite accumulation rate in the addition area is greater than 95%, the addition of the composition or agent is stopped.

[0027] By adopting the above technical solution, the present invention has the following beneficial effects:

[0028] 1. In this invention, hydroxylamine acetate is encapsulated by cyclodextrin and transported into the bacterial floc. After the cyclodextrin is degraded by microorganisms within the floc, the hydroxylamine acetate undergoes hydrolysis within the floc to generate NH2OH and acetic acid. The generated NH2OH is directly used to inhibit NOB. Furthermore, the generated acetic acid molecules can directly serve as a substrate for denitrifying bacteria within the floc, improving the utilization rate of the agent.

[0029] 2. In the technical solution of the present invention, NH2OH is generated inside the bacterial floc and utilized in situ, and the relative abundance and activity of NOB can be rapidly and significantly reduced. At the same time, since NH2OH is utilized more quickly by ammonia nitrogen oxidizing bacteria and anaerobic ammonia oxidizing bacteria in the bacterial floc, the ecological niche of ammonia nitrogen oxidizing bacteria and anaerobic ammonia oxidizing bacteria in the bacterial floc is significantly improved.

[0030] 3. The technical solution of this invention includes the slow release of a composition or agent of cyclodextrin and hydroxylamine acetate within the bacterial flocs, which can effectively maintain the long-term stability of short-cut nitrification-related wastewater treatment processes. The technical solution of this invention is applicable to various current biological treatment processes for short-cut nitrification-related wastewater and can effectively treat NO2... - When the -N accumulation rate decreases, it recovers quickly and remains stable, laying the foundation for the long-term stable operation of various short-cut nitrification-related wastewater biological treatment processes.

[0031] 4. In the technical solution of this invention, cyclodextrin, after entering the bacterial micelles and being decomposed, can be used as a carbon source for NO production. x- The reduction of -N improves the denitrification efficiency of the system. In particular, cyclodextrin, after degradation, can be used to treat the anaerobic ammonia oxidation byproduct NO3. - -N is reduced to NO2 - The carbon source for the -N reaction further replenishes the system with NO2. - -N, increases the system's NO2 - The system exhibits stability and high efficiency in N-N accumulation. Furthermore, acetic acid, produced by the hydrolysis of hydroxylamine acetate, is an excellent and efficient carbon source for denitrification. Together with cyclodextrin, it can provide electron donors for denitrifying bacteria within the system, significantly reducing the production of N2O, a greenhouse gas, thus achieving synergistic effects of efficient nitrogen removal and N2O emission reduction in the wastewater treatment system. Attached Figure Description

[0032] Figure 1A schematic diagram of a cyclodextrin molecule;

[0033] Figure 2 A schematic diagram illustrating the biological treatment of wastewater using the agent with adjustable microbial community structure to achieve short-cut nitrification as described in Example 4;

[0034] Figure 3 The results of bacterial nitrite accumulation rate tested using the reagents and application methods described in Example 4;

[0035] Figure 4 A schematic diagram illustrating the biological treatment of wastewater using the agent with adjustable microbial community structure to achieve short-cut nitrification as described in Example 5;

[0036] Figure 5 The results of nitrifying bacteria activity and nitrite accumulation rate tested using the reagents and application methods described in Example 5;

[0037] Figure 6 A schematic diagram illustrating the biological treatment of wastewater using the agent with adjustable microbial community structure to achieve short-cut nitrification as described in Example 6;

[0038] Figure 7 The results show the bacterial nitrite accumulation rate tested using the reagents and application methods described in Example 6. Detailed Implementation

[0039] The present invention provides a composition for achieving short-range nitrification by adjusting the microbial community structure, comprising cyclodextrin and hydroxylamine acetate, wherein the mass ratio of cyclodextrin to hydroxylamine acetate is preferably 1:(8-20), more preferably 1:(9-18), and even more preferably 1:(10-15).

[0040] In this invention, the cyclodextrin is preferably α-cyclodextrin, β-cyclodextrin, or γ-cyclodextrin (e.g., ...). Figure 1 ), and more preferably β-cyclodextrin.

[0041] The present invention provides a pharmaceutical preparation comprising the composition.

[0042] The present invention also provides the application of the said composition or agent in the biological treatment of short-cut nitrification-related wastewater.

[0043] In this invention, the composition or reagent is directly added to the dosing zone during use, and the concentration of the composition or reagent in the dosing zone is maintained at 1-10 mg / L (nitrogen content). The dosing zone of this invention preferably includes the dosing zone of a sequencing batch reactor or a continuous flow reactor. When using a sequencing batch reactor, the concentration c in the dosing zone is equal to the mass of nitrogen in the composition or reagent (M) and the reactor volume (V); when using a continuous flow reactor, the concentration c in the dosing zone is equal to the mass of nitrogen in the composition or reagent (M) and the flow rate Q at the dosing section.

[0044] In this invention, the dosing method includes using a sequencing batch reactor or a continuous flow reactor. When using a sequencing batch reactor, the dosing interval of the composition or reagent is preferably 0.5 to 2.0 times the hydraulic residence time; when using a continuous flow reactor, the continuous time for each dosing of the composition or reagent is preferably 1.0 to 3.0 times the hydraulic residence time.

[0045] In this invention, the pH of the dosing area is preferably maintained at 6.5-8.5.

[0046] In this invention, it is preferred to maintain the sludge concentration in the area where the composition or agent is added at 1000 to 10000 mg / L.

[0047] In this invention, preferably, the addition time of the composition or agent is determined based on the nitrite accumulation rate. When the nitrite accumulation rate is 80-95%, the dosage of the composition or agent is reduced by 20%-60%; when the nitrite accumulation rate is greater than 95%, the addition of the composition or agent is stopped.

[0048] In this invention, when the composition or agent is added, the amount of residual sludge discharged is reduced by 50%; when the addition of the composition or agent is stopped, the amount of residual sludge discharged returns to 100%.

[0049] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0050] Example 1

[0051] A composition for achieving short-range nitrification by adjusting the microbial community structure, comprising β-cyclodextrin and hydroxylamine acetate in a mass ratio of 1:8.

[0052] Example 2

[0053] A composition for achieving short-range nitrification by adjusting the microbial community structure, comprising β-cyclodextrin and hydroxylamine acetate in a mass ratio of 1:20.

[0054] Example 3

[0055] A composition for achieving short-range nitrification by adjusting the microbial community structure, comprising β-cyclodextrin and hydroxylamine acetate in a mass ratio of 1:15.

[0056] Example 4

[0057] An agent that can adjust the microbial community structure to achieve short-range nitrification:

[0058] Dissolve β-cyclodextrin in deionized water (to avoid the influence of metal ions in the water on hydroxylamine) at a concentration between 1% and 10%. Add 10 times the mass of hydroxylamine acetate to the solution containing β-cyclodextrin at room temperature (15–25°C) to form a saturated aqueous solution. Stir for 70 min at room temperature to ensure sufficient contact between hydroxylamine acetate and cyclodextrin. Sonicate the mixture while stirring to improve inclusion efficiency and rate. Rapidly cool the reaction mixture to 4±1°C, allowing precipitation to form. The inclusion complex can be separated by centrifugation or filtration. Then, dry the separated inclusion complex at 4±1°C to remove residual water, yielding the reagent.

[0059] Biological treatment of wastewater related to short-cut nitrification using the above-mentioned agents that can adjust the microbial community structure to achieve short-cut nitrification:

[0060] The reagent solution (e.g., ...) is added to the effluent end of the anaerobic zone of a continuous-flow municipal wastewater short-cut nitrification coupled anaerobic ammonium oxidation reactor via a dosing pump. Figure 2 Under constant influent flow conditions, the dosage and return flow are controlled to maintain the reagent concentration c in the dosing area at 5 mg / L (based on nitrogen). The pH of the dosing area is maintained at 7.1 ± 0.1.1 by replenishing with an alkaline solution (a 10% sodium bicarbonate solution). Each continuous dosing session lasts for three times the hydraulic retention time of the reactor (each continuous dosing session is 48 hours). The interval between two dosing sessions is 1.5 times the hydraulic retention time of the reactor (the interval between two dosing sessions is 24 hours). No residual sludge is discharged during the dosing process. When the nitrite accumulation rate is between 80% and 95%, the reagent dosage is reduced by 40%; when the nitrite accumulation rate is greater than 95%, the reagent dosing is stopped.

[0061] Example 5

[0062] An agent that can adjust the microbial community structure to achieve short-range nitrification:

[0063] Weigh β-cyclodextrin and hydroxylamine hydrochloride in a mass ratio of 1:15, place them in a mortar, and grind them with a pestle. Ensure thorough mixing during grinding until a uniform powder is formed. Grinding time is 10–30 minutes. Place the ground mixture at 4±1℃ for low-temperature drying to obtain the pharmaceutical preparation.

[0064] Biological treatment of wastewater related to short-cut nitrification using the above-mentioned agents that can adjust the microbial community structure to achieve short-cut nitrification:

[0065] A dry powder dosing device is used to simultaneously add reagent solutions (such as...) to the three aerobic zones of a continuous flow multi-stage A / O urban wastewater treatment process. Figure 4Under constant influent flow conditions, control the dosage and return flow to maintain the reagent concentration c in the dosing area at 3 mg / L (based on nitrogen). Add alkali solution (55% sodium hydroxide solution) to maintain the pH in the dosing area at 7.1 ± 0.1. Each continuous dosing session lasts up to four times the hydraulic retention time of the reactor (each continuous dosing session is 48 hours), and the interval between two dosing sessions is 1.5 times the hydraulic retention time of the reactor (the interval between two dosing sessions is 18 hours). When the nitrite accumulation rate is greater than 60%, the residual sludge discharge during the dosing process is reduced by 20%; when the nitrite accumulation rate is between 80% and 95%, the residual sludge discharge is reduced by 60%; when the nitrite accumulation rate is greater than 95%, the dosing is stopped, and the residual sludge discharge returns to its pre-dosing level.

[0066] Example 6

[0067] An agent that can adjust the microbial community structure to achieve short-range nitrification:

[0068] β-Cyclodextrin was prepared into a paste with a water content of 5% using deionized water. Then, 15 times the mass of hydroxylamine acetate was added to the paste, and the mixture was kneaded at 25°C for 2 hours to obtain a kneaded compound. The kneaded compound was then dried at 4±1°C to remove residual water, yielding the pharmaceutical preparation.

[0069] Biological treatment of wastewater related to short-cut nitrification using the above-mentioned agents that can adjust the microbial community structure to achieve short-cut nitrification:

[0070] In the initial stage of aeration in this reactor, a composite reagent solution (such as...) is added to the sequencing batch SPNA (single-stage short-path nitrification coupled with anaerobic ammonium oxidation) reactor in a single step using a measuring cylinder. Figure 6 The initial dosage was to maintain an initial reagent concentration (c) of 7.5 mg / L (based on nitrogen) in the reactor. Three additions were made on the first day, reducing excess sludge discharge by 90% during this period. After a one-day interval, three more additions were made daily. When the nitrite accumulation rate was between 80% and 95%, the dosage was maintained at an initial reagent concentration (c) of 5 mg N / L, reducing excess sludge discharge by 50%. Dosing was stopped when the nitrite accumulation rate exceeded 95%.

[0071] Experimental Example 1

[0072] Short-cut nitrification optimization tests were conducted based on Example 4. Influent ammonia nitrogen was controlled at 50±6 mg / L, and the pH of the addition zone (end of the anaerobic zone) was 7.2±0.2. Changes in ammonia nitrogen, nitrite, and nitrate nitrogen concentrations in the effluent from the anaerobic and aerobic zones were investigated. Results showed (e.g.) Figure 2 , Figure 3As shown in the diagram, this reactor can achieve a nitrite accumulation rate of over 65% on the 3rd day. After a 24-hour interval, it is added again for 48 hours. On the 5th day, the nitrite accumulation rate is over 85%, and on the 6th day, the nitrite accumulation rate reaches 95%. After stopping the addition, the amount of residual sludge discharged returns to the level before the addition, and the nitrite accumulation rate tends to stabilize, with a 30-day average of 93.6%. The nitrite concentration stabilizes at around 5.0 mg / L, and the nitrate nitrogen concentration remains below 0.5 mg / L.

[0073] Experimental Example 2

[0074] Short-cut nitrification optimization tests were conducted based on Example 5. Influent ammonia nitrogen was controlled at 53±5 mg / L. The pH values ​​at dosing point 1 were 7.5±0.2, at dosing point 2 were 7.2±0.2, and at dosing point 3 were 7.0±0.1. The changes in ammonia nitrogen, nitrite, and nitrate nitrogen concentrations at dosing points 2 and 3 were investigated. The results showed (e.g.) Figure 4 , Figure 5 As shown in the figure, the activities of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) are expressed as specific ammonia oxidation rate (SAOR) and specific nitrite oxidation rate (SNOR), respectively. The reactor achieved a nitrite accumulation rate exceeding 60% after 24 hours, with an SNOR to SAOR ratio of 0.84. After another 24 hours of dosing, the nitrite accumulation rate approached 70%, and the SNOR to SAOR ratio decreased to 0.39. After a 24-hour interval, following a third addition of the compound agent, the nitrite accumulation rate exceeded 95% on the fifth day, and the SNOR to SAOR ratio decreased to 0.08. After stopping the dosing, the excess sludge discharge returned to pre-dosing levels, the nitrite accumulation rate stabilized, and the SNOR to SAOR ratio stabilized around 0.08.

[0075] Experimental Example 3

[0076] Short-range nitrification optimization tests were conducted based on Example 6. Influent ammonia nitrogen was controlled at 55±4 mg / L. The pH during the aeration stage was adjusted to 7.2±0.2 using sodium bicarbonate. Changes in the concentrations of ammonia nitrogen, nitrite, and nitrate nitrogen in the reactor before and after aeration were observed. Results showed (e.g.) Figure 6 , Figure 7 As shown in the diagram, this reactor achieved a nitrite accumulation rate of over 75% after three additions of reagent on day 1. After a 24-hour interval, three more additions of reagent resulted in a nitrite accumulation rate of over 85%. Two more additions of reagent on day 5 resulted in a nitrite accumulation rate of 99%. After stopping the addition of reagent, the amount of residual sludge discharged returned to pre-additional levels. Over the following five days, the nitrite accumulation rate stabilized, with an average of 95.1%, indicating that short-cut nitrification had started rapidly and could maintain stability.

[0077] In summary, the technical solution described in this invention can effectively increase the concentration of NH2OH inside the bacterial micelles through the scientifically proportioned action of cyclodextrin and hydroxylamine acetate, thereby enhancing the inhibition efficiency of NH2OH on NOB and improving the system's NO2 concentration. - The stability and efficiency of -N accumulation can also effectively maintain the long-term stable operation of various short-cut nitrification-related biological wastewater treatment processes.

[0078] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. The application of a composition containing cyclodextrin and hydroxylamine acetate in the biological treatment of short-cut nitrification-related wastewater, characterized in that, The composition can regulate the microbial community structure and achieve short-range nitrification; The mass ratio of the cyclodextrin to hydroxylamine acetate is 1:(8~20); the cyclodextrin is α-cyclodextrin, β-cyclodextrin or γ-cyclodextrin; During use, the composition is directly added to the dosing area, and the concentration of the composition in the dosing area is maintained at 1~10 mg / L (nitrogen value), and the pH of the dosing area is maintained at 6.5-8.

5. The preparation process of the composition is as follows: β-cyclodextrin is dissolved in deionized water to avoid the influence of metal ions in the water on hydroxylamine, with a concentration between 1% and 10%. At room temperature (15-25°C), 10 times the mass of hydroxylamine acetate is added to the solution containing β-cyclodextrin to form a saturated aqueous solution. The mixture is stirred at room temperature for 70 minutes to ensure sufficient contact between hydroxylamine acetate and cyclodextrin. Ultrasonic treatment is performed simultaneously with stirring to improve inclusion efficiency and rate. The reaction mixture is rapidly cooled to 4±1°C, and a precipitate is formed. The inclusion complex is separated by centrifugation or filtration. Subsequently, the separated inclusion complex is dried at 4±1°C to remove residual water, yielding the composition. Alternatively, the preparation process of the composition is as follows: weigh β-cyclodextrin and hydroxylamine hydrochloride in a mass ratio of 1:15, put the weighed cyclodextrin and hydroxylamine hydrochloride into a mortar, and grind them with a pestle; ensure that the two are fully mixed during grinding until a uniform powder is formed, the grinding time is 10~30 minutes, and place the ground mixture at a low temperature of 4±1℃ to dry, to obtain the composition; Alternatively, the preparation process of the composition is as follows: β-cyclodextrin is prepared into a paste with a water content of 5% using deionized water, and then 15 times the mass of hydroxylamine acetate is added to the paste, and kneaded at 25°C for 2 hours to obtain a kneaded compound; then the kneaded compound is dried at 4±1°C to remove residual water to obtain the composition.

2. The application according to claim 1, characterized in that, The methods of delivery include using a sequencing batch reactor or a continuous flow reactor; When using a sequencing batch reactor, the addition interval of the composition is 0.5 to 2.0 times the hydraulic retention time; the concentration c in the addition zone = mass of nitrogen in the composition M / reactor volume V; When using a continuous flow reactor, the duration of each addition of the composition is 1.0 to 3.0 times the hydraulic retention time; the concentration in the addition zone c = mass of nitrogen in the composition M / flow rate Q at the addition section.

3. The application according to claim 1, characterized in that, The sludge concentration in the dosing area is 1000 mg / L to 10000 mg / L; When the nitrite accumulation rate in the addition area is 80-95%, the dosage of the composition is reduced by 20-60%; when the nitrite accumulation rate in the addition area is greater than 95%, the addition of the composition is stopped.

Images