A long-acting slow-release sludge denitrifying bacterial community regulating agent, preparation method and application

Abstract

The present invention belongs to the technical field of sewage treatment, and discloses a long-acting slow-release sludge denitrifying flora regulating agent, a preparation method and an application thereof. The preparation method includes: uniformly mixing dolomite powder, hydroxylamine-O-sulfonic acid powder and ethylhydrazine oxalate powder to obtain a composite powder; mixing hydroxypropyl cellulose with an ethanol aqueous solution to obtain a sizing agent; mixing the composite powder and the sizing agent and preparing the long-acting slow-release sludge denitrifying flora regulating agent through a granulation technique. The agent of the present invention can be applied in the process of treating nitrogen-containing wastewater, and can quickly regulate the flora structure to realize the start-up and performance optimization of the nitrite-based sewage denitrification process.

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 denitrifying flora regulating agent, a preparation method thereof, and an application thereof. Background Art

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

[0003] The literature "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 shortcut nitrification using a combined inhibitor. In a stable SBR or MBBR, it is repeatedly added in the manner of formic acid, hydrazine, hydrazine, and other conditions remain unchanged, and the nitritation rate is stably achieved above 92%.

[0005] CN118388028A discloses a method for starting and maintaining shortcut nitrification by hydroxylamine combined with high dissolved oxygen to inhibit nitrifying bacteria and ammonia-oxidizing bacteria throughout the process. Shortcut nitrification is quickly started by adding hydroxylamine to inhibit NOB.

[0006] According to the above-mentioned prior art, by contacting hydroxylamine and / or hydrazine with nitrite oxidizing bacteria in the activated sludge, the activity of nitrite oxidizing bacteria can be effectively inhibited, thereby achieving nitrite accumulation. However, in the above-mentioned prior art, hydroxylamine and hydrazine must be first dissolved in water and then contact with the activated sludge to inhibit nitrite oxidizing bacteria. Since hydroxylamine and / or hydrazine are reducing substances, they can undergo non-biochemical reactions with oxygen and nitrite in water, resulting in a reduction in their effective utilization rate, not only wasting the agent but also generating a large amount of nitrous oxide. At the same time, sludge bulking often occurs during the startup process of shortcut nitrification. Therefore, improving the effective contact between the inhibitor and nitrite oxidizing bacteria and reducing the consumption of hydroxylamine and / or hydrazine by non-biochemical reactions are the key points and difficulties of such methods. At the same time, improving the sedimentation performance of sludge is also the key point and difficulty in the process of nitrite accumulation. Summary of the Invention

[0007] The object of the present invention is to provide, in view of the deficiencies of the prior art, a long-acting slow-release sludge denitrifying flora regulating agent, a preparation method thereof, and an application thereof. The agent of the present invention can be applied in the process of treating nitrogen-containing wastewater to quickly regulate the flora structure and achieve the start-up and performance optimization of the nitrite-based sewage denitrification process.

[0008] To achieve the above object, in the first aspect of the present invention, a preparation method of a long-acting slow-release sludge denitrifying flora regulating agent is provided, and the preparation method includes the following steps:

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

[0010] S2: Mix hydroxypropyl cellulose and an ethanol aqueous solution to obtain a mucilage;

[0011] S3: Mix the composite powder and the mucilage and prepare the long-acting slow-release sludge denitrifying flora regulating agent through a granulation technique.

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

[0013] The dolomite powder is prepared by crushing dolomite and passing through a sieve of 80-200 meshes;

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

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

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

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

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

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

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

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

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

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

[0024] The concentration of hydroxypropyl cellulose in the mucilage is 1.5 - 2.5%.

[0025] According to the present invention, preferably, the bulk density of the long-acting slow-release sludge denitrifying flora 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 denitrifying flora regulating agent is 0.08 - 0.2 mm.

[0027] The second aspect of the present invention provides a long-acting slow-release sludge denitrifying flora regulating agent prepared by the preparation method of the long-acting slow-release sludge denitrifying flora regulating agent described above.

[0028] The third aspect of the present invention provides the application of the long-acting slow-release sludge denitrifying flora regulating agent in sewage biological treatment.

[0029] According to the present invention, preferably, the dosing mode of the long-acting slow-release sludge denitrifying flora regulating agent is continuous dosing or intermittent dosing.

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

[0031] According to the present invention, preferably, the dosing area of the long-acting slow-release sludge denitrifying flora regulating agent is on the side of the system for sewage biological treatment and / or in situ in the main stream system.

[0032] According to the present invention, preferably, the dosing amount of the long-acting slow-release sludge denitrifying flora regulating agent is 5 - 50 mg / g VSS.

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

[0034] When the nitrate accumulation rate in the system for sewage biological treatment is lower than 10%, the dosing amount of the long-acting slow-release sludge denitrifying flora regulating agent is not higher than 10 mg / g VSS.

[0035] According to the present invention, preferably, when the long-acting and slow-release sludge denitrifying flora regulating agent is added to the system for sewage biological treatment, the discharge amount of excess sludge in the system for sewage biological treatment is reduced by 20-100%; after the addition of the long-acting and slow-release sludge denitrifying flora regulating agent is stopped, the discharge amount of excess sludge in the system for sewage biological treatment resumes to 100%;

[0036] After the long-acting and slow-release sludge denitrifying flora regulating agent is added to the system for sewage biological treatment, the excess sludge in the system for sewage biological treatment should pass through a 50-150 mesh sieve during discharge, and the intercepted matter should be re-input into the system for sewage biological treatment.

[0037] In the present invention, the long-acting and slow-release sludge denitrifying flora regulating agent is obtained by compounding dolomite powder, hydroxylamine-O-sulfonic acid powder, ethylhydrazine oxalate powder and hydroxypropyl cellulose (using hydroxypropyl cellulose as the coating for dolomite powder, hydroxylamine-O-sulfonic acid powder and ethylhydrazine oxalate powder); after the long-acting and slow-release sludge denitrifying flora 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 contacts with the activated sludge and enters the interior of the activated sludge along with the process of crushing and recombination of the activated sludge. Since the solubility of hydroxypropyl cellulose in water is poor, the dolomite powder, hydroxylamine-O-sulfonic acid powder and ethylhydrazine oxalate powder will not be instantaneously released due to contact with water, which is the first stage of slow release;

[0039] When the long-acting and slow-release sludge denitrifying flora regulating agent of the present invention enters the interior of the activated sludge, due to the water solubility and degradability of hydroxypropyl cellulose, the hydroxypropyl cellulose on the surface of the agent gradually loses its wrapping property, and the dolomite powder, hydroxylamine-O-sulfonic acid powder and ethylhydrazine oxalate powder are gradually released. The hydroxylamine-O-sulfonic acid powder and ethylhydrazine oxalate powder dissolve in the aqueous solution inside the activated sludge, gradually hydrolyze and ionize to produce hydroxylamine and hydrazine, and diffuse towards the outside of the activated sludge, gradually inhibiting the nitrite-oxidizing bacteria in the activated sludge, which is the second stage of slow release;

[0040] Through the two-stage slow release effect, the long-acting property and high utilization efficiency of the agent of the present invention are ensured. In addition, hydrogen ions are generated during the hydrolysis of hydroxylamine-O-sulfonic acid powder and ethylhydrazine oxalate, which can promote the effective release of calcium ions, magnesium ions and iron ions rich in the dolomite powder. Under the action of the raw water phosphate and hydroxide, these ions form hydroxyapatite and hydroxyferric phosphate crystal nuclei, increasing the weight of the activated sludge and improving the sludge sedimentation performance.

[0041] The beneficial effects of the technical solution of the present invention are as follows: The long-acting and slow-release sludge denitrifying flora regulating agent of the present invention can be applied in the process of treating nitrogen-containing wastewater, and can quickly regulate the flora structure to realize the start-up and performance optimization of the nitrite-based sewage denitrification process (realize nitrite accumulation). The long-acting and slow-release sludge denitrifying flora 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 characteristics of strong biocompatibility, easy degradability, low cost and gelling property of the natural polymer material hydroxypropyl cellulose to tightly combine dolomite powder, hydroxylamine-O-sulfonic acid powder, ethylhydrazine oxalate powder with flocculent sludge, improving sludge aggregation and sedimentation.

[0043] 2) The agent of the present invention can significantly reduce the activity of NOB in the biological pool: When enriching nitrifying bacteria sludge by the present invention, after hydroxypropyl cellulose is degraded by microorganisms in the sludge, hydroxylamine-O-sulfonic acid powder and ethylhydrazine oxalate powder are slowly released and directly act on NOB, causing its relative abundance and activity to rapidly decline. This reduces the concentration of the agent in the external aqueous solution of the sludge, improves the use efficiency of the agent, and avoids the influence of a relatively high residual agent concentration on the effluent quality.

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

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

[0046] 5) The agent of the present invention has strong adaptability: The present invention is applicable to various current short-cut nitrification-related sewage biological treatment processes, and can improve sludge sedimentation while accumulating NO2 - -N.

[0047] Other features and advantages of the present invention will be described in detail in the subsequent specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] By describing the exemplary embodiments of the present invention in more detail in conjunction with the drawings, the above and other objects, features and advantages of the present invention will become more obvious. Among them, in the exemplary embodiments of the present invention, the same reference numerals generally represent the same components.

[0049] Figure 1 Shows a macro view (Olympus CX33) of the long-acting and slow-release sludge denitrifying flora regulating agent prepared by the preparation method of the long-acting and slow-release sludge denitrifying flora regulating agent provided in Example 1 of the present invention.

[0050] Figure 2 Shows the test result graph of the nitrate nitrogen accumulation rate of the long-acting slow-release sludge denitrifying flora regulating agent obtained in Example 1 of the present invention.

[0051] Figure 3 Shows the test result graph of the activated sludge sedimentation property of the long-acting slow-release sludge denitrifying flora regulating agent obtained in Example 1 of the present invention (SVI is the sludge volume index).

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

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

[0054] Figures 6(a)-(c) show the test result graph of the activated sludge particle size of the long-acting slow-release sludge denitrifying flora regulating agent obtained in Example 3 of the present invention. Detailed implementation manners

[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 example provides a preparation method of a long-acting slow-release sludge denitrifying flora regulating agent, and the preparation method includes the following steps:

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

[0059] Mix the dolomite powder, hydroxylamine-O-sulfonic acid powder and ethylhydrazine oxalate powder according to a mass ratio of 1:4:4 to obtain a mixed system, stir for 20 min, ultrasonicate for 5 min, and cycle 3 times to obtain a composite powder;

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

[0061] S3: Mix the composite powder and the sizing agent, and obtain the long-acting slow-release sludge denitrifying flora regulating agent through wet granulation technology.

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

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

[0064] The dosage for the first 3 days is 30 mg / g VSS, and the excess sludge discharge is reduced by 80%; then for the next 3 days, the dosage is 15 mg / g VSS, and the excess sludge discharge is reduced by 60%; subsequently, for 3 consecutive days, the dosage is 5 mg / g VSS, and the excess sludge discharge is reduced by 20%; then the addition of the agent stops, and the excess sludge discharge resumes to 100%; after the agent is added, the excess sludge should pass through an 80-mesh sieve during discharge, and the retained matter should be re-injected into the continuous flow AOA process.

[0065] Example 2

[0066] This embodiment provides a preparation method for a long-acting slow-release sludge denitrifying flora regulating agent, and the preparation method includes the following steps:

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

[0068] Mix the dolomite powder, hydroxylamine-O-sulfonic acid powder and ethylhydrazine oxalate powder according to a mass ratio of 1:3:5 to obtain a mixed system, stir for 25 min, ultrasonicate for 5 min, and cycle 5 times to obtain a composite powder;

[0069] S2: Mix hydroxypropyl cellulose with a 70% ethanol aqueous solution to obtain a sizing agent with a concentration of 2%;

[0070] S3: Mix the composite powder and the sizing agent, and obtain the long-acting slow-release sludge denitrifying flora regulating agent through wet granulation technology.

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

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

[0073] The dosage of the medicament in this embodiment is 25 mg / g VSS, the discharge of excess sludge is reduced by 80%, and it is continuously added for 5 days; subsequently, the addition of the medicament is stopped and the discharge of excess sludge resumes to 100%; after the addition of the medicament, the excess sludge should pass through a 100-mesh sieve during discharge, and the intercepted matter is re-fed into the continuous-flow IFAS process.

[0074] Example 3

[0075] This embodiment provides a preparation method of a long-acting and slow-release sludge denitrifying flora regulating medicament, and the preparation method includes the following steps:

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

[0077] Mix the dolomite powder, hydroxylamine-O-sulfonic acid powder and ethylhydrazine oxalate powder according to a mass ratio of 1:4:2 to obtain a mixed system, stir for 25 min, ultrasonicate for 5 min, and cycle 3 times to obtain a composite powder;

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

[0079] S3: Mix the composite powder and the mucilage and prepare the long-acting and slow-release sludge denitrifying flora regulating medicament through wet granulation technology.

[0080] This embodiment applies the long-acting and slow-release sludge denitrifying flora regulating medicament to an SBR sewage biological treatment system:

[0081] The medicament in this embodiment is added in the influent stage of the SBR sewage biological treatment system, and the medicine is added once a day;

[0082] The dosage is 35 mg / g VSS, the discharge of excess sludge is reduced by 50%, and it is continuously added for 7 days; subsequently, the addition of the medicament is stopped and the discharge of excess sludge resumes to 100%; after the addition of the medicament, the excess sludge should pass through a 90-mesh sieve during discharge, and the intercepted matter is re-fed into the continuous-flow AOA process.

[0083] Test Example 1

[0084] This test example conducts nitrate nitrogen control tests and activated sludge sedimentation tests on Example 1, and the results show that:

[0085] As Figure 2As shown, after adding the agent of Example 1, the continuous-flow AOA process can achieve a reduction in the nitrate (i.e., nitrate nitrogen) accumulation rate to 20% on the 3rd day. The nitrate accumulation rate is below 10% on the 5th day and as low as 4% on the 9th day. After the agent addition stops, the nitrate nitrogen accumulation rate tends to be stable, with an average value of 7.6% over 30 days. The nitrite nitrogen (nitrite) concentration is stable at around 5.0 mg / L, and the nitrate nitrogen concentration remains below 0.5 mg / L. As Figure 3 shown, during this process, the sedimentation performance of the activated sludge gradually improves, and the SVI value gradually decreases from 143 before adding the agent to around 60 after 15 days of operation.

[0086] Test Example 2

[0087] This test example conducts tests on the denitrifying functional microorganism activity and nitrite accumulation performance of Example 2, and the results show that:

[0088] As Figure 4 shown, among them, the activities of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) are expressed by the specific ammonia oxidation rate (SAOR) and the specific nitrite oxidation rate (SNOR).

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

[0090] After continuously adding the agent for 72 hours, the nitrite (nitrite nitrogen) accumulation rate is higher than 80%, and the SNOR drops to 1.62 mg N / (gVSS·h).

[0091] On the 5th day of continuous dosing, the nitrite (nitrite nitrogen) accumulation rate is higher than 95%, and the SNOR drops to 0.67 mg N / (gVSS·h).

[0092] After the agent addition stops, the excess sludge discharge volume returns to that before adding the agent, the nitrite (nitrite nitrogen) accumulation rate tends to be stable, the SNOR is stably less than 1 mg N / (gVSS·h), and the SAOR ratio is stably around 8.0 mg N / (gVSS·h).

[0093] Test Example 3

[0094] This test example conducts nitrite accumulation tests and activated sludge particle size tests on Example 3, and the results show that:

[0095] As Figure 5 shown:

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

[0097] After adding chemicals on the second day, the nitrite accumulation rate is higher than 75%, and the DO in the aeration stage after adding chemicals is controlled not higher than 1.5 mg / L.

[0098] After adding chemicals again on the 5th day, the nitrite accumulation rate reaches 99%, and the DO in the aeration stage is controlled not higher than 2.0 mg / L.

[0099] After stopping adding chemicals, the DO in the aeration stage is controlled not higher than 1.5 mg / L, and the discharge amount of excess sludge resumes to that before adding chemicals. In the following 15 days, the nitrite accumulation rate tends to be stable, and the average value of the nitrite accumulation rate is 97.6%. It can be seen from this that shortcut nitrification has been quickly started and can be maintained stably.

[0100] At the same time, as shown in Figures 6(a)-(c), the particle size of the activated sludge gradually increases after adding chemicals. On the first day, the activated sludge in the SBR sewage biological treatment system is mainly in flocs. After 15 days of operation with adding chemicals, small particles appear in the flocs. After 45 days of operation, the particles in the flocs increase significantly.

[0101] The embodiments of the present invention have been described above. The above description is exemplary and not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations are obvious to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A preparation method of a long-acting and slow-release sludge denitrifying flora regulating agent, characterized in that, The preparation method includes the following steps: S1: Mix dolomite powder, hydroxylamine-O-sulfonic acid powder, and ethylhydrazine oxalate powder evenly to obtain a composite powder; S2: Mix hydroxypropyl cellulose and an aqueous ethanol solution to obtain a mucilage; S3: Mix the composite powder and the mucilage and prepare the long-acting slow-release sludge denitrifying flora regulating agent through a granulation technique.

2. The preparation method of the long-acting slow-release sludge denitrifying flora regulating agent according to claim 1, wherein, In the step S1: The dolomite powder is obtained by crushing dolomite and passing it through a sieve with 80 - 200 meshes; The hydroxylamine-O-sulfonic acid powder is obtained by grinding hydroxylamine-O-sulfonic acid crystals in a nitrogen environment and passing it through a sieve with 80 - 200 meshes; The ethylhydrazine oxalate powder is obtained by grinding ethylhydrazine oxalate in a nitrogen environment and passing it through a sieve with 80 - 200 meshes; 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 evenly mixing the dolomite powder, hydroxylamine-O-sulfonic acid powder, and ethylhydrazine oxalate powder includes: mixing the dolomite powder, hydroxylamine-O-sulfonic acid powder, and ethylhydrazine oxalate powder to obtain a mixed system, and successively and cyclically stirring and ultrasonically treating the mixed system to obtain a composite powder.

3. The preparation method of the long-acting and slow-release sludge denitrifying flora regulating agent according to claim 2, wherein, The time for the stirring treatment is 15 - 30 min.

4. The preparation method of the long-acting slow-release sludge denitrifying flora regulating agent according to claim 2, wherein, The time for the ultrasonic treatment is 5 - 10 min.

5. The preparation method of the long-acting and slow-release sludge denitrifying bacterial community regulating agent according to claim 2, wherein, The number of cycles is 3 - 5 times.

6. The preparation method of the long-acting slow-release sludge denitrifying flora regulating agent according to claim 1, wherein, In the step S2: The hydroxypropyl cellulose is high-substituted hydroxypropyl cellulose; The mass fraction of the aqueous ethanol solution is 25 - 85%; The concentration of hydroxypropyl cellulose in the mucilage is 1.5 - 2.5%.

7. According to the preparation method of the long-acting slow-release sludge denitrifying flora regulating agent described in claim 1, wherein, The bulk density of the long-acting slow-release sludge denitrifying bacterial community regulating agent is 1.3 - 1.6 g / cm 3 ; The particle size of the long-acting slow-release sludge denitrifying flora regulating agent is 0.08 - 0.2 mm.

8. The long-acting slow-release sludge denitrifying flora regulating agent prepared by the preparation method of the long-acting slow-release sludge denitrifying flora regulating agent described in any one of claims 1 - 7.

9. The application of the long-acting slow-release sludge denitrifying flora regulating agent described in claim 8 in sewage biological treatment.

10. According to the application described in claim 9, wherein, The dosing method of the long-acting slow-release sludge denitrifying flora regulating agent is continuous dosing or intermittent dosing; The dosing amount of the long-acting slow-release sludge denitrifying flora regulating agent is determined by the sludge concentration in the dosing area and / or the nitrate accumulation rate in the system for the sewage biological treatment; When the long-acting slow-release sludge denitrifying flora regulating agent is dosed into the system for the sewage biological treatment, the discharge amount of excess sludge in the system for the sewage biological treatment is reduced by 20 - 100%; After the dosing of the long-acting slow-release sludge denitrifying flora regulating agent stops, the discharge amount of excess sludge in the system for the sewage biological treatment resumes to 100%; After the long-acting slow-release sludge denitrifying flora regulating agent is dosed into the system for the sewage biological treatment, the excess sludge in the system for the sewage biological treatment should pass through a sieve with 50 - 150 meshes during discharge, and the intercepted matter should be re-injected into the system for the sewage biological treatment.

11. The application according to claim 10, wherein, The dosing area of the long-acting slow-release sludge denitrifying flora regulating agent is on the side of the system for the biological treatment of the sewage and / or in-situ in the main-stream system.

12. The application according to claim 10 or 11, wherein The dosing amount of the long-acting slow-release sludge denitrifying flora regulating agent is 5 - 50 mg / g VSS.

13. According to the application described in claim 10, wherein, When the nitrate accumulation rate in the system for the biological treatment of the sewage is higher than 80%, the dosing amount of the long-acting slow-release sludge denitrifying flora regulating agent is not less than 20 mg / g VSS; When the nitrate accumulation rate in the system for the biological treatment of the sewage is lower than 10%, the dosing amount of the long-acting slow-release sludge denitrifying flora regulating agent is not higher than 10 mg / g VSS.

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