Long-acting slow-release sludge denitrification flora regulating agent as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of sewage treatment, and discloses a long-acting slow-release sludge denitrification flora regulating agent as well as a preparation method and application thereof. The preparation method comprises the following steps: uniformly mixing dolomite powder, hydroxylamine-O-sulfonic acid powder and ethylhydrazine oxalate powder to obtain composite powder; mixing hydroxypropyl cellulose with an ethanol water solution to obtain mucilage; and mixing the composite powder and mucilage, and preparing the long-acting slow-release sludge denitrification flora adjusting agent through a granulation technology. The agent disclosed by the invention is applied to the nitrogenous wastewater treatment process, and the flora structure can be quickly adjusted to realize the start-up and performance optimization of a sewage denitrification process based on nitrite.

Description

Technical Field

[0001] The present invention belongs to the technical field of sewage treatment, and more specifically, relates to a long-acting slow-release sludge denitrification bacteria community regulating agent, a preparation method and an application thereof. Background Art

[0002] Currently, problems such as nitrogen pollution in water bodies are still very serious. In the process of development and upgrading of sewage treatment technology, the sewage denitrification process based on nitrite has many characteristics, such as saving oxygen supply and reducing energy consumption, reducing carbon source consumption and reducing material consumption, reducing sludge generation and reducing sludge treatment costs. However, most sewage does not contain nitrite, so how to achieve a continuous supply of nitrite in the sewage treatment process is a difficult problem.

[0003] The article "A critical review of exogenous additives for improving the anammox process" points out that hydroxylamine (NH2OH) and hydrazine (N2H4) can effectively inhibit nitrite oxidizing bacteria and achieve nitrite accumulation, but the dosage needs to be optimized.

[0004] CN109437394B discloses a method for controlling short-range nitrification using a combined inhibitor. In a stable SBR or MBBR, formic acid, hydrazine, and hydrazine are repeatedly added, and other conditions remain unchanged, so as to stably achieve a nitrification rate of more than 92%.

[0005] CN118388028A discloses a method for starting and maintaining short-range nitrification by combining hydroxylamine with high dissolved oxygen to inhibit nitrifying bacteria and full-range ammonia oxidizing bacteria, and quickly starting short-range nitrification by adding hydroxylamine to inhibit NOB.

[0006] According to the above-mentioned prior art, the activity of nitrite oxidizing bacteria can be effectively inhibited by contacting hydroxylamine and / or hydrazine with nitrite oxidizing bacteria in activated sludge, thereby achieving nitrite accumulation. However, in the above-mentioned prior art, hydroxylamine and hydrazine must first be dissolved in water before they can contact with activated sludge, thereby inhibiting nitrite oxidizing bacteria. Since hydroxylamine and / or hydrazine are reducing substances, they can react non-biochemically with oxygen and nitrite in water, resulting in a decrease in their effective utilization rate, which not only wastes reagents but also produces a large amount of nitrous oxide. At the same time, sludge swelling often occurs during the startup of short-range nitrification. Therefore, improving the effective contact between inhibitors and nitrite oxidizing bacteria and reducing the consumption of hydroxylamine and / or hydrazine by non-biochemical reactions are the key points and difficulties of this type of method. At the same time, improving the sedimentation performance of sludge is also the key point and difficulty of the nitrite accumulation process. Summary of the invention

[0007] The purpose of the present invention is to address the deficiencies of the prior art and to propose a long-acting slow-release sludge denitrification bacterial community regulating agent, a preparation method and an application thereof. The agent of the present invention is used in the treatment process of nitrogen-containing wastewater to quickly regulate the bacterial community structure and realize the start-up and performance optimization of the nitrite-based wastewater denitrification process.

[0008] In order to achieve the above object, the present invention provides a first aspect of a method for preparing a long-acting slow-release sludge denitrification bacteria regulating agent, the preparation method comprising the following steps:

[0009] S1: mixing dolomite powder, hydroxylamine-O-sulfonic acid powder and ethylhydrazine oxalate powder uniformly to obtain a composite powder;

[0010] S2: mixing hydroxypropyl cellulose with ethanol aqueous solution to obtain a slurry;

[0011] S3: The composite powder and the slurry are mixed and the long-acting slow-release sludge denitrification bacteria regulating agent is prepared by granulation technology.

[0012] According to the present invention, preferably, in step S1:

[0013] The dolomite powder is obtained by crushing dolomite and passing it through a 80-200 mesh sieve;

[0014] The hydroxylamine-O-sulfonic acid powder is prepared by grinding hydroxylamine-O-sulfonic acid crystals in a nitrogen environment and passing through an 80-200 mesh sieve;

[0015] The ethylhydrazine oxalate powder is prepared by grinding ethylhydrazine oxalate in a nitrogen environment and passing through a 80-200 mesh sieve;

[0016] The mass ratio of the dolomite powder, hydroxylamine-O-sulfonic acid powder and ethylhydrazine oxalate powder is 1:(2-10):(2-5);

[0017] The method for uniformly mixing dolomite powder, hydroxylamine-O-sulfonic acid powder and ethylhydrazine oxalate powder comprises: mixing the dolomite powder, hydroxylamine-O-sulfonic acid powder and ethylhydrazine oxalate powder to obtain a mixed system, and sequentially stirring and ultrasonically treating the mixed system to obtain a composite powder;

[0018] Preferably, the stirring time is 15-30 min;

[0019] Preferably, the ultrasonic treatment time is 5-10 min;

[0020] Preferably, the number of cycles is 3-5 times.

[0021] According to the present invention, preferably, in step S2:

[0022] The hydroxypropyl cellulose is a highly substituted hydroxypropyl cellulose;

[0023] The mass fraction of the ethanol aqueous solution is 25-85%;

[0024] The concentration of hydroxypropylcellulose in the slurry is 1.5-2.5%.

[0025] According to the present invention, preferably, the bulk density of the long-acting slow-release sludge denitrification bacteria regulating agent is 1.3-1.6 g / cm 3 .

[0026] According to the present invention, preferably, the particle size of the long-acting slow-release sludge denitrification bacteria community regulating agent is 0.08-0.2 mm.

[0027] The second aspect of the present invention provides a long-acting slow-release sludge denitrification bacteria population regulating agent prepared by the preparation method of the long-acting slow-release sludge denitrification bacteria population regulating agent.

[0028] The third aspect of the present invention provides the use of the long-acting slow-release sludge denitrification bacteria community regulating agent in sewage biological treatment.

[0029] According to the present invention, preferably, the long-acting slow-release sludge denitrifying bacteria community regulating agent is added in a continuous or intermittent manner.

[0030] According to the present invention, preferably, the dosage of the long-acting slow-release sludge denitrifying bacteria community regulating agent is determined by the sludge concentration in the addition area and / or the nitrate accumulation rate in the system for the biological treatment of sewage.

[0031] According to the present invention, preferably, the region for adding the long-acting slow-release sludge denitrifying bacteria regulating agent is the side of the system for biological treatment of the sewage and / or in-situ of the mainstream system.

[0032] According to the present invention, preferably, the dosage of the long-acting slow-release sludge denitrification bacteria community regulating agent is 5-50 mg / g VSS.

[0033] According to the present invention, preferably, when the cumulative rate of nitrate in the system for biological treatment of sewage is higher than 80%, the dosage of the long-acting slow-release sludge denitrification bacteria regulating agent is not less than 20 mg / g VSS;

[0034] When the cumulative rate of nitrate in the system for biological treatment of sewage is lower than 10%, the dosage of the long-acting slow-release sludge denitrification bacteria regulating agent is not higher than 10 mg / g VSS.

[0035] According to the present invention, preferably, when the long-acting slow-release sludge denitrification bacteria regulating agent is added to the system for the biological treatment of sewage, the amount of residual sludge discharged in the system for the biological treatment of sewage is reduced by 20-100%; after the addition of the long-acting slow-release sludge denitrification bacteria regulating agent is stopped, the amount of residual sludge discharged in the system for the biological treatment of sewage is restored to 100%;

[0036] After the long-acting slow-release sludge denitrifying bacteria regulating agent is added to the system for biological sewage treatment, the remaining sludge in the system for biological sewage treatment should be sieved through a 50-150 mesh screen when discharged, and the intercepted material should be re-introduced into the system for biological sewage treatment.

[0037] In the present invention, the present invention obtains a long-acting slow-release sludge denitrification bacteria group regulating agent by compounding dolomite powder, hydroxylamine-O-sulfonic acid powder, ethylhydrazine oxalate powder and hydroxypropyl cellulose (using hydroxypropyl cellulose as a coating for dolomite powder, hydroxylamine-O-sulfonic acid powder and ethylhydrazine oxalate powder); after the long-acting slow-release sludge denitrification bacteria group regulating agent of the present invention is added to the sewage biological treatment system:

[0038] Under the action of mechanical stirring, aeration stirring or hydraulic mixing, it comes into contact with the activated sludge and enters the activated sludge during the crushing and reorganization process of the activated sludge. Since hydroxypropyl cellulose has poor solubility in water, it will not release dolomite powder, hydroxylamine-O-sulfonic acid powder and ethylhydrazine oxalate powder instantly due to contact with water. This is the first level of sustained release;

[0039] When the long-acting slow-release sludge denitrification bacteria regulating agent of the present invention enters the activated sludge, the hydroxypropyl cellulose on the agent surface gradually loses its wrapping properties due to the water solubility and degradability of hydroxypropyl cellulose, and the dolomite powder, hydroxylamine-O-sulfonic acid powder and ethylhydrazine oxalate powder are gradually released, and the hydroxylamine-O-sulfonic acid powder and ethylhydrazine oxalate powder are dissolved in the aqueous solution inside the activated sludge, and gradually hydrolyze and ionize hydroxylamine and hydrazine, and diffuse to the outside of the activated sludge, so that the nitrite oxidizing bacteria in the activated sludge are gradually inhibited. This is the second slow release;

[0040] The double sustained-release effect ensures the long-term effectiveness and high-efficiency utilization of the agent of the present invention. In addition, when hydroxylamine-O-sulfonic acid powder and ethylhydrazine oxalate are hydrolyzed, hydrogen ions are generated, which can promote the effective release of calcium ions, magnesium ions and iron ions rich in dolomite powder. These ions form hydroxyl calcium phosphate and hydroxyl iron phosphate crystal nuclei under the action of raw water phosphate and hydroxide, increase the weight of activated sludge, and improve sludge sedimentation.

[0041] The beneficial effects of the technical solution of the present invention are as follows: the long-acting slow-release sludge denitrification bacterial community regulating agent of the present invention is used in the process of treating nitrogen-containing wastewater, and can quickly adjust the bacterial community structure to achieve the start-up and performance optimization of the nitrite-based sewage denitrification process (achieving nitrite accumulation). The long-acting slow-release sludge denitrification bacterial community regulating agent of the present invention can be specifically applied to the work of improving the standard and efficiency of sewage biological treatment. Specifically:

[0042] 1) The agent of the present invention utilizes the strong biocompatibility, easy degradability, low cost and gelling properties of hydroxypropyl cellulose, a natural polymer material, to tightly combine dolomite powder, hydroxylamine-O-sulfonic acid powder, ethylhydrazine oxalate powder and flocculent sludge to improve the sludge aggregation and sedimentation properties.

[0043] 2) The agent of the present invention can significantly reduce the activity of NOB in the biological pool: when the nitrifying bacteria are enriched in the sludge by the present invention, after the hydroxypropyl cellulose is degraded by the microorganisms in the sludge, the hydroxylamine-O-sulfonic acid powder and the ethylhydrazine oxalate powder are slowly released, directly acting on NOB, causing the relative abundance and activity to decrease rapidly. The agent concentration in the aqueous solution outside the sludge is reduced, the agent use efficiency is improved, and the high residual agent concentration that affects the effluent water quality is avoided.

[0044] 3) The agent of the present invention can significantly enhance the AOB activity in the biological pond: The present invention can significantly increase the activity and abundance of denitrifying autotrophic bacteria such as ammonia oxidizing bacteria and anaerobic ammonia oxidizing bacteria in the biological pond.

[0045] 4) The dual sustained-release design of the drug of the present invention makes the inhibitory effect of the drug of the present invention on NOB more lasting, more effective and more significant.

[0046] 5) The agent of the present invention has strong adaptability: the present invention is applicable to all current short-range nitrification-related sewage biological treatment processes, and can be used in NO2 - -N accumulation while improving sludge settling properties.

[0047] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present invention.

[0049] Figure 1 A macro image (Olympus CX33) of a long-acting slow-release sludge denitrification bacteria community regulating agent prepared by the preparation method of a long-acting slow-release sludge denitrification bacteria community regulating agent provided in Example 1 of the present invention is shown.

[0050] Figure 2 The graph shows the test results of the nitrate nitrogen accumulation rate of the long-acting slow-release sludge denitrification bacteria community regulating agent obtained in Example 1 of the present invention.

[0051] Figure 3 The activated sludge settling test result of the long-acting slow-release sludge denitrification bacteria community regulating agent obtained in Example 1 of the present invention is shown (SVI is the sludge settling index).

[0052] Figure 4 The graph shows the test results of the nitrifying bacteria activity and nitrite accumulation performance of the long-acting slow-release sludge denitrifying bacteria community regulating agent obtained in Example 2 of the present invention.

[0053] Figure 5 The graph shows the test results of the nitrifying bacteria activity and nitrite accumulation performance of the long-acting slow-release sludge denitrifying bacteria community regulating agent obtained in Example 3 of the present invention.

[0054] 6(a)-(c) show the results of the activated sludge particle size test of the long-acting slow-release sludge denitrification bacteria community regulating agent obtained in Example 3 of the present invention. DETAILED DESCRIPTION

[0055] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0056] Example 1

[0057] This embodiment provides a method for preparing a long-acting slow-release sludge denitrification bacterial flora regulating agent, the preparation method comprising the following steps:

[0058] S1: crushing dolomite and passing through a 120-mesh sieve to obtain dolomite powder; grinding hydroxylamine-O-sulfonic acid crystals in a nitrogen environment and passing through a 150-mesh sieve to obtain hydroxylamine-O-sulfonic acid powder; grinding ethylhydrazine oxalate in a nitrogen environment and passing through a 150-mesh sieve to obtain ethylhydrazine oxalate powder;

[0059] Dolomite powder, hydroxylamine-O-sulfonic acid powder and ethylhydrazine oxalate powder were mixed in a mass ratio of 1:4:4 to obtain a mixed system, stirred for 20 minutes, ultrasonicated for 5 minutes, and cycled for 3 times to obtain a composite powder;

[0060] S2: Mix hydroxypropyl cellulose with 70% ethanol aqueous solution to obtain a 2% slurry;

[0061] S3: The composite powder and the slurry are mixed and the long-acting slow-release sludge denitrification bacteria regulating agent is prepared by wet granulation technology.

[0062] In this embodiment, the long-acting slow-release sludge denitrification bacteria regulating agent is applied to the continuous flow AOA process:

[0063] The reagent of this embodiment is added in the anaerobic zone of the continuous flow AOA process and is continuously added in situ in the mainstream system;

[0064] The dosage in the first 3 days was 30 mg / g VSS, and the residual sludge discharge was reduced by 80%; the dosage in the next 3 days was 15 mg / g VSS, and the residual sludge discharge was reduced by 60%; the dosage was 5 mg / g VSS for the next 3 consecutive days, and the residual sludge discharge was reduced by 20%; then the dosage of the agent was stopped, and the residual sludge discharge recovered to 100%; after the addition of the agent, the residual sludge should be sieved through an 80-mesh sieve when discharged, and the retained material should be re-introduced into the continuous flow AOA process.

[0065] Example 2

[0066] This embodiment provides a method for preparing a long-acting slow-release sludge denitrification bacterial flora regulating agent, the preparation method comprising the following steps:

[0067] S1: crushing dolomite and passing through a 150-mesh sieve to obtain dolomite powder; grinding hydroxylamine-O-sulfonic acid crystals in a nitrogen environment and passing through a 150-mesh sieve to obtain hydroxylamine-O-sulfonic acid powder; grinding ethylhydrazine oxalate in a nitrogen environment and passing through a 150-mesh sieve to obtain ethylhydrazine oxalate powder;

[0068] Dolomite powder, hydroxylamine-O-sulfonic acid powder and ethylhydrazine oxalate powder were mixed in a mass ratio of 1:3:5 to obtain a mixed system, stirred for 25 minutes, ultrasonicated for 5 minutes, and cycled for 5 times to obtain a composite powder;

[0069] S2: Mix hydroxypropyl cellulose with 70% ethanol aqueous solution to obtain a 2% slurry;

[0070] S3: The composite powder and the slurry are mixed and the long-acting slow-release sludge denitrification bacteria regulating agent is prepared by wet granulation technology.

[0071] In this embodiment, the long-acting slow-release sludge denitrification bacteria regulating agent is applied to the continuous flow IFAS process:

[0072] The reagent of this embodiment is added to the return sludge of the continuous flow IFAS process;

[0073] The dosage of the agent in this embodiment is 25 mg / g VSS, and the residual sludge discharge is reduced by 80%, and the agent is added continuously for 5 days; then the agent addition is stopped, and the residual sludge discharge is restored to 100%; after the agent is added, the residual sludge should be sieved through a 100-mesh sieve when discharged, and the retained material should be re-introduced into the continuous flow IFAS process.

[0074] Example 3

[0075] This embodiment provides a method for preparing a long-acting slow-release sludge denitrification bacterial flora regulating agent, the preparation method comprising the following steps:

[0076] S1: crushing dolomite and passing through a 90-mesh sieve to obtain dolomite powder; grinding hydroxylamine-O-sulfonic acid crystals in a nitrogen environment and passing through a 120-mesh sieve to obtain hydroxylamine-O-sulfonic acid powder; grinding ethylhydrazine oxalate in a nitrogen environment and passing through a 120-mesh sieve to obtain ethylhydrazine oxalate powder;

[0077] Dolomite powder, hydroxylamine-O-sulfonic acid powder and ethylhydrazine oxalate powder were mixed in a mass ratio of 1:4:2 to obtain a mixed system, stirred for 25 minutes, ultrasonicated for 5 minutes, and cycled for 3 times to obtain a composite powder;

[0078] S2: Mix hydroxypropyl cellulose with 70% ethanol aqueous solution to obtain a 2% slurry;

[0079] S3: The composite powder and the slurry are mixed and the long-acting slow-release sludge denitrification bacteria regulating agent is prepared by wet granulation technology.

[0080] In this embodiment, the long-acting slow-release sludge denitrification bacteria regulating agent is applied to the SBR sewage biological treatment system:

[0081] The agent of this embodiment is added at the water inlet stage of the SBR sewage biological treatment system, once a day;

[0082] When the dosage is 35 mg / g VSS, the discharge of residual sludge is reduced by 50%, and the dosage is continued for 7 days; then the dosage of the agent is stopped, and the discharge of residual sludge is restored to 100%; after the dosage of the agent, the residual sludge should be screened through a 90-mesh sieve when discharged, and the retained material should be re-dosed into the continuous flow AOA process.

[0083] Test Example 1

[0084] This test example conducted a nitrate nitrogen control test and an activated sludge settling test on Example 1, and the results showed that:

[0085] like Figure 2As shown, after adding the reagent of Example 1, the continuous flow AOA process can achieve a nitrate (i.e., nitrate nitrogen) accumulation rate of 20% on the 3rd day. The nitrate accumulation rate was lower than 10% on the 5th day, and the nitrate accumulation rate was as low as 4% on the 9th day. After the addition of the reagent was stopped, the nitrate nitrogen accumulation rate tended to be stable, with a 30-day average of 7.6%. The nitrite nitrogen (nitrite) concentration was stable at about 5.0 mg / L, and the nitrate nitrogen concentration was continuously lower than 0.5 mg / L. Figure 3 As shown in the figure, during this process, the settling performance of activated sludge gradually improved, and the SVI value gradually decreased from 143 before adding the drug to about 60 after 15 days of operation.

[0086] Test Example 2

[0087] This test example tests the denitrification function microbial activity and nitrite accumulation performance of Example 2. The results show that:

[0088] like Figure 4 As shown, 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).

[0089] The continuous flow IFAS process can achieve a nitrite (nitrite nitrogen) accumulation rate of more than 60% after 48 hours of dosing, with a SAOR of 7.21 mg N / (gVSS·h), and a SNOR decrease from 6.33 mg N / (gVSS·h) to 2.84 mg N / (gVSS·h);

[0090] After continuous addition of reagent 72, the accumulation rate of nitrite (nitrite nitrogen) was higher than 80%, and the SNOR dropped to 1.62 mg N / (gVSS·h).

[0091] On the fifth day of continuous addition, the accumulation rate of nitrite (nitrite nitrogen) was higher than 95%, and the SNOR dropped to 0.67 mg N / (gVSS·h).

[0092] After the addition of the agent was stopped, the residual sludge discharge returned to the level before the addition of the agent, the accumulation rate of nitrite (nitrite nitrogen) tended to be stable, the SNOR was stable at less than 1 mg N / (gVSS·h), and the SAOR ratio was stable at around 8.0 mg N / (gVSS·h).

[0093] Test Example 3

[0094] This test example conducted a nitrite accumulation test and an activated sludge particle size test on Example 3. The results showed that:

[0095] like Figure 5 As shown:

[0096] The SBR wastewater biological treatment system can achieve a nitrite accumulation rate higher than 55% after adding the agent on the first day, and the DO in the aeration stage after the addition of the agent is controlled below 1.0 mg / L.

[0097] After dosing on the second day, the nitrite accumulation rate was higher than 75%, and the DO was controlled at no higher than 1.5 mg / L during the aeration stage after dosing.

[0098] After adding the agent again on the 5th day, the nitrite accumulation rate reached 99%, and the DO in the aeration stage was controlled at no more than 2.0 mg / L.

[0099] After the addition of the agent was stopped, the DO in the aeration stage was controlled at no more than 1.5 mg / L, and the residual sludge discharge returned to the level before the addition of the agent. In the following 15 days, the nitrite accumulation rate tended to be stable, and the average nitrite accumulation rate was 97.6%. It can be seen that short-term nitrification has been quickly started and can be maintained stable.

[0100] At the same time, as shown in Figure 6(a)-(c), the particle size of the activated sludge gradually increased after the addition of the drug. On the first day, the activated sludge in the SBR sewage biological treatment system was mainly flocs. After 15 days of operation with the addition of the drug, tiny particles appeared in the flocs. After 45 days of operation, the number of particles in the flocs increased significantly.

[0101] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A method for preparing a long-acting slow-release sludge denitrification bacterial flora regulating agent, characterized in that: The preparation method comprises the following steps: S1: mixing dolomite powder, hydroxylamine-O-sulfonic acid powder and ethylhydrazine oxalate powder uniformly to obtain a composite powder; S2: mixing hydroxypropyl cellulose with ethanol aqueous solution to obtain a slurry; S3: The composite powder and the slurry are mixed and the long-acting slow-release sludge denitrification bacteria regulating agent is prepared by granulation technology.

2. The method for preparing the long-acting slow-release sludge denitrification bacterial flora regulating agent according to claim 1, wherein: In step S1: The dolomite powder is obtained by crushing dolomite and passing it through a 80-200 mesh sieve; The hydroxylamine-O-sulfonic acid powder is prepared by grinding hydroxylamine-O-sulfonic acid crystals in a nitrogen environment and passing through an 80-200 mesh sieve; The ethylhydrazine oxalate powder is prepared by grinding ethylhydrazine oxalate in a nitrogen environment and passing through a 80-200 mesh sieve; The mass ratio of the dolomite powder, hydroxylamine-O-sulfonic acid powder and ethylhydrazine oxalate powder is 1:(2-10):(2-5); The method for uniformly mixing dolomite powder, hydroxylamine-O-sulfonic acid powder and ethylhydrazine oxalate powder comprises: mixing the dolomite powder, hydroxylamine-O-sulfonic acid powder and ethylhydrazine oxalate powder to obtain a mixed system, and sequentially stirring and ultrasonically treating the mixed system to obtain a composite powder; Preferably, the stirring time is 15-30 min; Preferably, the ultrasonic treatment time is 5-10 min; Preferably, the number of cycles is 3-5 times.

3. The method for preparing the long-acting slow-release sludge denitrification bacterial flora regulating agent according to claim 1, wherein: In step S2: The hydroxypropyl cellulose is a highly substituted hydroxypropyl cellulose; The mass fraction of the ethanol aqueous solution is 25-85%; The concentration of hydroxypropylcellulose in the slurry is 1.5-2.5%.

4. The method for preparing the long-acting slow-release sludge denitrification bacterial flora regulating agent according to claim 1, wherein: The bulk density of the long-acting slow-release sludge denitrification bacteria regulating agent is 1.3-1.6 g / cm 3 ; The particle size of the long-acting slow-release sludge denitrification bacteria regulating agent is 0.08-0.2 mm.

5. The long-acting slow-release sludge denitrification bacteria population regulating agent prepared by the preparation method of the long-acting slow-release sludge denitrification bacteria population regulating agent described in any one of claims 1 to 4.

6. Use of the long-acting slow-release sludge denitrification bacterial flora regulating agent according to claim 5 in biological sewage treatment.

7. The use according to claim 6, wherein: The long-acting slow-release sludge denitrification bacteria regulating agent is added in a continuous or intermittent manner; The dosage of the long-acting slow-release sludge denitrification bacteria regulating agent is determined by the sludge concentration in the addition area and / or the nitrate accumulation rate in the system for the biological treatment of sewage; When the long-acting slow-release sludge denitrification bacteria regulating agent is added to the system for biological sewage treatment, the amount of excess sludge discharged in the system for biological sewage treatment is reduced by 20-100%; After the addition of the long-acting slow-release sludge denitrification bacteria regulating agent is stopped, the residual sludge discharge in the sewage biological treatment system is restored to 100%; After the long-acting slow-release sludge denitrifying bacteria regulating agent is added to the system for biological sewage treatment, the remaining sludge in the system for biological sewage treatment should be sieved through a 50-150 mesh screen when discharged, and the intercepted material should be re-introduced into the system for biological sewage treatment.

8. The use according to claim 7, wherein: The addition area of ​​the long-acting slow-release sludge denitrification bacteria community regulating agent is the side of the system for the sewage biological treatment and / or the main stream system in situ.

9. The use according to claim 7 or 8, wherein: The dosage of the long-acting slow-release sludge denitrification bacteria regulating agent is 5-50 mg / g VSS.

10. The use according to claim 7, wherein: When the cumulative rate of nitrate in the system for biological treatment of sewage is higher than 80%, the dosage of the long-acting slow-release sludge denitrification bacteria regulating agent is not less than 20 mg / g VSS; When the cumulative rate of nitrate in the system for biological treatment of sewage is lower than 10%, the dosage of the long-acting slow-release sludge denitrification bacteria regulating agent is not higher than 10 mg / g VSS.

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