A material for enhancing high-efficiency denitrification of sewage and a preparation method thereof

Abstract

This application relates to the technical field of wastewater treatment materials in the water environment sector, specifically disclosing a high-efficiency denitrification material for enhancing wastewater treatment and its preparation method. The high-efficiency denitrification material for enhancing wastewater treatment comprises the following raw materials by mass percentage: 30-60% sulfur powder; 20-35% porous powder; 10-25% limestone powder; and 1-5% foaming agent. The high-efficiency denitrification material of this application has a high denitrification capacity and can maintain high-efficiency operation for a long time after a single addition. During denitrification in wastewater, there is no problem of insufficient or excessive carbon source. Only normal influent is required, and the denitrifying bacteria inside the material can utilize the sulfur and carbon sources within the material to carry out denitrification. Therefore, the high-efficiency denitrification material of this application has the advantages of lower cost, stable denitrification, and high denitrification efficiency.

Description

Technical Field

[0001] This application relates to the technical field of wastewater treatment materials in the water environment sector, and more specifically, it relates to a material for enhancing efficient nitrogen removal from wastewater and a method for preparing the same. Background Technology

[0002] Nitrogen and phosphorus are two common nutrients in water bodies. When their concentrations are too high, they cause eutrophication, leading to the deterioration of aquatic ecosystems. In recent years, national and local governments have successively introduced policies to address nitrogen and phosphorus pollution in water bodies. For example, Guangdong Province's "14th Five-Year Plan" for Marine Ecological Environment Protection mentions promoting the revision and formulation of local water pollutant discharge standards, adding total nitrogen control indicators. It also emphasizes upgrading and transforming wastewater treatment plants with total nitrogen reduction as the goal, and implementing actions to reduce nitrogen and phosphorus pollution and improve water quality in rivers flowing into the sea. Shenzhen's 2022 Nearshore Marine Pollution Prevention and Control Work Plan mentions exploring pilot projects for total nitrogen emission control in key industries, encouraging the reduction of total ammonia emissions on the basis of meeting emission standards, and promoting research on efficient and low-carbon nitrogen and phosphorus removal wastewater treatment processes.

[0003] Among related technologies, phosphorus treatment in wastewater shows good results and the processes are relatively mature, such as adding chemical agents for flocculation and sedimentation, and using phosphorus adsorption materials for adsorption and fixation. However, nitrogen removal in wastewater treatment is currently not ideal. In wastewater treatment plants, liquid carbon sources such as sodium acetate are typically added to improve denitrification and thus achieve nitrogen removal. However, several problems remain in the implementation of this process. Adding too much carbon source not only wastes resources but also causes secondary pollution due to excessively high COD; adding too little carbon source results in insufficient carbon supply for the denitrification process, which in turn affects the nitrogen removal effect.

[0004] Regarding the aforementioned technologies, the inventors believe that the denitrification process has always suffered from drawbacks such as high cost, complex process, complex operation and maintenance, slow denitrification speed, and unstable denitrification effect. Summary of the Invention

[0005] To address the shortcomings of high cost, complex processes, complex operation and maintenance, slow denitrification speed, and unstable denitrification effect in denitrification processes, this application provides a high-efficiency denitrification material for enhancing wastewater and its preparation method. The raw materials used in this application for preparing the denitrification material are widely available, and the preparation process is simple. Therefore, the denitrification material is low in cost, effective, easy to use, and convenient to prepare. It is also widely applicable and can be used in various wastewater denitrification and phosphorus removal fields, truly meeting the characteristics of high efficiency, simplicity, low cost, and stability.

[0006] In the first aspect, this application provides a material for enhancing efficient nitrogen removal from wastewater, employing the following technical solution:

[0007] A material for enhancing efficient nitrogen removal from wastewater comprises the following raw materials by mass percentage: 30-60% sulfur powder; 20-35% porous powder; 10-25% limestone powder; and 1-5% foaming agent.

[0008] By adopting the above technical solution, sulfur is a pale yellow or yellow powder, relatively brittle, and possesses hydrophobic and water-impermeable properties; while limestone powder becomes slightly alkaline when soaked in water and can release Ca. 2+ It has a certain effect on removing phosphorus from water; porous powder, while increasing the carbon source (a type of slow-release carbon source that slowly releases carbon source in water), also increases the porosity of the material, which facilitates the attachment and proliferation of microorganisms; foaming agent is used to generate bubbles during processing to increase the internal porosity of the denitrification material, thereby increasing its specific surface area and enhancing the attachment effect of microorganisms.

[0009] The high-efficiency denitrification material used in this application contains both a sulfur source and a slow-release carbon source, and has both autotrophic and heterotrophic denitrification microbial communities, which can achieve the purpose of denitrification more efficiently. Moreover, the CO2 produced by heterotrophic denitrification can be used as the inorganic carbon source required for autotrophic denitrification. While being highly efficient, it also reduces the need for external reagents.

[0010] Sulfur, as a sulfur source, has a good denitrification effect, but it has poor water permeability and is not easy for microorganisms to attach to. In addition to increasing the specific surface area of ​​the material by foaming with a foaming agent to generate numerous small pores and thus enhance the exchange of water inside and outside the material, this application also uses porous powder. Because porous powder slowly releases carbon source and has a loose and rough internal structure, it is very conducive to the attachment and growth of microbial communities, thereby improving the denitrification rate of microbial communities.

[0011] Furthermore, the autotrophic denitrification process requires a continuous consumption of alkalinity. The application proposes adding limestone powder, which effectively provides suitable alkalinity for the autotrophic denitrification reaction, thereby accelerating the denitrification rate. Simultaneously, the SO4 produced by the reaction... 2- Ca can also be produced from limestone 2+ The sedimentation process allows the SO4 in the effluent to be trapped by the packing material, significantly reducing the SO4 content in the effluent. 2- The risk of excessively high concentrations, and excess Ca 2+ It can also adsorb some of the phosphorus, reducing the phosphorus concentration in the effluent.

[0012] Compared to existing denitrification processes that require the regular and quantitative addition of carbon sources to ensure the normal progress of denitrification and achieve denitrification, which is not only costly but also complex to operate and maintain, the high-efficiency denitrification material of this application has a high denitrification capacity and can maintain high-efficiency operation for a long time after a single addition. This high-efficiency denitrification material does not suffer from insufficient or excessive carbon sources during its use in wastewater denitrification; it only requires normal influent, and the denitrifying bacteria inside the material can utilize the sulfur and carbon sources within the material to carry out denitrification. Therefore, the high-efficiency denitrification material of this application has the advantages of lower cost, stable denitrification, and high denitrification efficiency.

[0013] Furthermore, existing denitrification processes mainly involve adding carbon sources to wastewater treatment plants, such as aerated filters, MBR, and A / O systems. The actual application of solid materials is rare, occurring only in applications with specific needs (such as adsorption resins for removing high concentrations of nitrate nitrogen and zeolites for removing ammonia nitrogen). In processes that remove total nitrogen through microorganisms, continuous addition of carbon sources is required to ensure efficient and stable denitrification. This means that when the system enters the wastewater treatment process, the carbon source is automatically added in the appropriate amount based on the wastewater's entry into the corresponding treatment unit. The amount of carbon source added depends on the influent nitrate nitrogen concentration and wastewater volume; generally, based on the approximate operating cycle, the carbon source is added approximately 2-4 times per day. In this application, the highly efficient denitrification material prepared in this application does not require further addition of carbon sources to the system. Under certain biochemical reactions, the material continuously consumes its internal sulfur source to carry out denitrification, achieving rapid and efficient denitrification of wastewater.

[0014] Preferably, the porous powder is one or more of sawdust, straw pellets, and coconut shell powder.

[0015] By adopting the above technical solution, the porous powder used in this application has a loose and rough internal structure, which is conducive to the attachment and production of microbial colonies, thereby effectively improving the denitrification rate of microbial colonies.

[0016] Preferably, the porous powder has a particle size of 100-150 mesh.

[0017] Preferably, the sulfur powder has a particle size of 150-250 mesh.

[0018] Preferably, the limestone powder has a particle size of 150-250 mesh.

[0019] Preferably, the foaming agent is one of sodium carbonate, sodium bicarbonate, sodium dodecylbenzene sulfonate, animal keratin, and surfactant.

[0020] Secondly, this application provides a method for preparing a high-efficiency nitrogen removal material for enhanced wastewater treatment, employing the following technical solution:

[0021] A method for preparing a high-efficiency nitrogen removal material for enhanced wastewater treatment includes the following steps:

[0022] Step 1: Mix the porous powder and limestone powder by mass percentage for 5-10 minutes to form mixture A;

[0023] Step 2: Add pure water to mixture A and stir evenly for 1-3 minutes to make mixture A moist.

[0024] Step 3: Add sulfur powder to mixture A from step 2 according to the mass percentage, and stir for 5-10 minutes to obtain a moist mixture B;

[0025] Step 4: Dry mixture B by air drying or baking at a temperature of 25~45℃, add foaming agent to mixture B, and then stir for 1~5 minutes to obtain mixture C;

[0026] Step 5: Heat mixture C to 135~145℃ and stir for 5~10 minutes;

[0027] Step 6: After the sulfur in mixture C has completely melted and been stirred evenly, quickly feed it into a pelletizing machine for extrusion molding. After natural cooling, it becomes a high-efficiency denitrification material.

[0028] By adopting the above technical solution, the preparation method of this application is simple, without complex and demanding process steps, the materials are easy to obtain and inexpensive, and no toxic substances are generated; the prepared high-efficiency denitrification material has high porosity and strong water permeability, and is relatively lightweight, making it flexible and convenient to use, and not restricted by the scene or water pollution status. It can be used as an adsorption packing material in fixed sewage treatment devices and as a fluidized bed packing material, as a high-concentration nitrogen and phosphorus sewage treatment material; it can also be used as a functional packing material for denitrification and phosphorus removal in constructed wetlands or as an in-situ purification material for sewage bodies, as a deep denitrification and phosphorus removal material for sewage, with a wide range of applications.

[0029] Preferably, in step two, the amount of pure water added is 10-20% of the mass of mixture A.

[0030] Preferably, the particle size of the high-efficiency denitrification material is 5-20 mm, and the shape is rod-shaped or spherical.

[0031] By adopting the above technical solution, the high-efficiency denitrification material prepared in this application can exhibit a white-yellow to yellow color, with a rough surface and high porosity (apparent density 400~800Kg / m³). 3 It has strong compressive strength (5~10MPa).

[0032] In summary, this application has the following beneficial effects:

[0033] 1. The high-efficiency denitrification material of this application has a high denitrification capacity and can maintain high-efficiency operation for a long time after a single addition. There is no problem of insufficient or excessive carbon source during the denitrification process in wastewater. As long as normal water intake is required, the denitrifying bacteria inside the material can use the sulfur source and carbon source in the material to carry out denitrification reaction to remove nitrogen. Therefore, the high-efficiency denitrification material of this application has the effects of lower cost, stable denitrification and high denitrification efficiency.

[0034] 2. The porous powder used in this application has a loose and rough internal structure, which is conducive to the attachment and production of microbial colonies, thereby effectively improving the denitrification rate of microbial colonies.

[0035] 3. The preparation method of this application is simple, without complex and demanding process steps, the materials are easy to obtain and inexpensive, and no toxic substances are generated; the prepared high-efficiency denitrification material has high porosity and strong water permeability, and is relatively light, with a wide range of applications, and the application method is flexible and convenient, not restricted by the scene or water pollution status. Attached Figure Description

[0036] Figure 1 Here is a physical image of the high-efficiency denitrification material prepared in Example 1 of this application;

[0037] Figure 2 This is a diagram illustrating the effect of the high-efficiency denitrification material prepared in Example 1 of this application in removing nitrogen pollutants from wastewater; Detailed Implementation

[0038] Currently, nitrogen removal in wastewater treatment is not yet ideal. In wastewater treatment plants, liquid carbon sources such as sodium acetate are typically added to improve denitrification and thus achieve nitrogen removal. However, several problems exist in the implementation of this process. Adding too much carbon source not only wastes resources but also causes secondary pollution due to excessively high COD levels; adding too little carbon source results in insufficient carbon supply for the denitrification process, which in turn affects the nitrogen removal efficiency.

[0039] The high-efficiency denitrification material developed by the applicant through extensive research has a high denitrification capacity and can maintain high-efficiency operation for a long time after a single addition. The high-efficiency denitrification material of this application does not have the problem of insufficient or excessive carbon source during the denitrification process in wastewater. As long as normal water intake is required, the denitrifying bacteria inside the material can use the sulfur source and carbon source in the material to carry out denitrification reaction. Therefore, the high-efficiency denitrification material of this application has the effects of lower cost, stable denitrification and high denitrification efficiency.

[0040] The present invention will now be described in detail with reference to the embodiments. The scope of protection of this application is not limited to the following embodiments.

[0041] The following raw materials involved in the embodiments of this application are all commercially available: sulfur powder, limestone powder, sawdust, straw pellets, coconut shell powder, pure water, sodium carbonate, sodium bicarbonate, sodium dodecylbenzene sulfonate, animal keratin protein, and surfactants.

[0042] The following is in conjunction with the appendix Figure 1-2 The present application will be further described in detail with reference to the embodiments. It should be noted that the models and manufacturers of the raw materials mentioned above are only for the purpose of fully disclosing the raw materials in this application, and should not be construed as limiting the source of the raw materials. The raw materials used in actual applications are not limited to the manufacturers mentioned above, and raw materials from other manufacturers with equivalent effects are also applicable. Example

[0043] Example 1

[0044] A method for preparing a high-efficiency nitrogen removal material for enhanced wastewater treatment includes the following steps:

[0045] Step 1: According to the mass percentage, add 30% of porous wood chips and 18% of limestone powder into a mixer and mix them. The mixing speed is 100 r / min and the mixing time is 5 min. Mix until uniform to form mixture A.

[0046] Step 2: Add pure water to mixture A, where the amount of pure water added is 10-20% of the mass of mixture A. Then continue stirring at a speed of 300 r / min for 2 minutes to ensure thorough stirring and make mixture A moist.

[0047] Step 3: According to the mass percentage, add 50% sulfur powder evenly to the moist mixture A, and then stir and mix evenly at a stirring speed of 60 r / min for 10 min to obtain the moist mixture B.

[0048] Step 4: Allow mixture B from Step 3 to air dry naturally until the surface is no longer noticeably damp. Then, weigh out 2% of the foaming agent sodium bicarbonate according to the mass percentage and add it to the dried mixture B. Stir evenly at a speed of 500 r / min for 1 min to obtain mixture C.

[0049] Step 5: Heat mixture C in an oil bath to 135~145℃ and stir continuously for 8 minutes at a stirring speed of 50 r / min, so that the sulfur powder in mixture C is completely melted.

[0050] Step 6: After the sulfur in mixture C has completely melted and been stirred evenly, quickly feed it into a pelletizing machine for extrusion molding to produce a high-efficiency denitrification material.

[0051] Example 2

[0052] A method for preparing a high-efficiency nitrogen removal material for enhanced wastewater treatment includes the following steps:

[0053] Step 1: According to the mass percentage, add 20% porous wood chips and 15% limestone powder into a mixer and mix them. The mixing speed is 300 r / min and the mixing time is 3 min. Mix until uniform to form mixture A.

[0054] Step 2: Add pure water to mixture A, where the amount of pure water added is 10-20% of the mass of mixture A. Then continue stirring at a speed of 200 r / min for 3 minutes to ensure thorough stirring and make mixture A moist.

[0055] Step 3: According to the mass percentage, add 60% of the sulfur powder evenly to the moist mixture A, and then stir and mix evenly at a stirring speed of 180 r / min for 5 min to obtain the moist mixture B.

[0056] Step 4: Allow mixture B from Step 3 to air dry naturally until the surface is no longer noticeably damp. Then, weigh out 5% of the foaming agent sodium bicarbonate according to the mass percentage and add it to the dried mixture B. Stir well at a speed of 300 r / min for 3 min to obtain mixture C.

[0057] Step 5: Heat mixture C in an oil bath to 135~145℃ and stir continuously for 5 minutes at a stirring speed of 100r / min, so that the sulfur powder in mixture C is completely melted.

[0058] Step 6: After the sulfur in mixture C has completely melted and been stirred evenly, quickly feed it into a pelletizing machine for extrusion molding to produce a high-efficiency denitrification material.

[0059] Example 3

[0060] A method for preparing a high-efficiency nitrogen removal material for enhanced wastewater treatment includes the following steps:

[0061] Step 1: According to the mass percentage, add 35% porous wood chips and 25% limestone powder into a mixer and mix them. The mixing speed is 50 r / min and the mixing time is 10 min. Mix until uniform to form mixture A.

[0062] Step 2: Add pure water to mixture A, where the amount of pure water added is 10-20% of the mass of mixture A. Then continue stirring at a speed of 500 r / min for 1 minute to ensure thorough stirring and make mixture A moist.

[0063] Step 3: According to the mass percentage, add 39% sulfur powder evenly to the wet mixture A, and then stir and mix evenly at a stirring speed of 100 r / min for 8 min to obtain the wet mixture B.

[0064] Step 4: Dry mixture B from Step 3 at a temperature of 25-45℃ until no obvious moisture is visible on the surface. Then, weigh 1% of the foaming agent sodium bicarbonate according to the mass percentage and add it to the dried mixture B. Stir evenly at a speed of 100 r / min for 5 minutes to obtain mixture C. It is necessary to strictly control the drying temperature. If the temperature is too high, some of the porous materials, such as sodium bicarbonate, will decompose in this step, which will affect the foaming effect in subsequent steps.

[0065] Step 5: Heat mixture C in an oil bath to 135~145℃ and stir continuously for 10 minutes at a stirring speed of 30 r / min, so that the sulfur powder in mixture C is completely melted.

[0066] Step 6: After the sulfur in mixture C has completely melted and been stirred evenly, quickly feed it into a pelletizing machine for extrusion molding to produce a high-efficiency denitrification material.

[0067] In summary, the high-efficiency denitrification material prepared in this application can be extruded into plum-shaped or rod-shaped forms as needed, with a particle size between 5 and 20 mm. The specific size is prepared according to the application scenario and wastewater treatment requirements.

[0068] Performance testing

[0069] Depending on the composition ratio, the material can range from white to yellow, with a rough surface, high porosity, and low density (apparent density 400~800 kg / m³). 3 It has strong compressive strength (5~10MPa). (Refer to...) Figure 1 100g of the high-efficiency denitrification material prepared in Example 1 was placed in a beaker and soaked for 7 days. The material was intact and without any breakage or cracks. After being taken out and dried, the dry weight was measured to be 98.6%, which means that the loss rate was less than 2%. This indicates that the denitrification and phosphorus removal material prepared by the present invention still has high integrity and mechanical strength after being soaked in water.

[0070] Reference Figure 2 The denitrification effect of the high-efficiency denitrification material prepared in Example 1 is shown below:

[0071] A cylindrical device was fabricated using plexiglass, with a height of 1200 mm and a diameter of 100 mm. The cylinder was filled from bottom to top with 200 mm of crushed stone (15-30 mm particle size), 400 mm of the high-efficiency denitrification material (8-15 mm particle size) of this application, and 400 mm of crushed stone (5-10 mm particle size). First, anaerobic wastewater (after coarse filtration of sludge suspension) retrieved from a wastewater treatment plant was added to the filled column for biofilm formation. After 7 days, normal continuous influent was introduced, with a total nitrogen (TN) concentration of 10-20 mg / L. Biofilm formation was considered successful when the TN removal rate of the effluent exceeded 50%. Subsequently, the TN concentration of the effluent was continuously monitored and recorded daily. To verify the denitrification stability of the high-efficiency denitrification material prepared in this application, the effects were tested under three operating conditions: hydraulic retention times of 12 h, 6 h, and 2 h.

[0072] The results showed that the total nitrogen removal effect of the high-efficiency denitrification material prepared in this application was significant and stable throughout the entire operation cycle. The TN concentrations in the effluent at 12h, 6h, and 2h were 0.45mg / L, 0.73mg / L, and 0.59mg / L, respectively, with average removal rates of 96.63%, 93.25%, and 95.19%. These results indicate that the prepared high-efficiency denitrification material can effectively and stably remove nitrogen pollutants from wastewater.

[0073] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A method for preparing a high-efficiency nitrogen removal material for enhanced wastewater treatment, characterized in that, Includes the following steps: Step 1: The following raw materials are included by mass percentage: sulfur powder 30-60%; porous powder 20-35%; limestone powder 10-25%; foaming agent 1-5%. The porous powder and limestone powder are mixed and stirred for 5-10 minutes to form mixture A. Step 2: Add pure water to mixture A and stir it evenly to make mixture A moist. Step 3: Add sulfur powder to mixture A from step 2 according to the mass percentage, and stir evenly to obtain a moist mixture B; Step 4: Dry mixture B by air drying or baking at a temperature of 25~45℃, add foaming agent to mixture B, and then stir evenly to obtain mixture C; Step 5: Heat mixture C to 135~145℃ and stir for 5~10 minutes; Step 6: After the sulfur in mixture C has completely melted and been stirred evenly, it is poured into a molding machine for extrusion molding, which yields a high-efficiency denitrification material. In step two, the amount of pure water added is 10-20% of the mass of mixture A.

2. The method for preparing high-efficiency nitrogen removal materials for enhanced wastewater treatment according to claim 1, characterized in that: The high-efficiency denitrification material has a particle size of 5-20 mm and is rod-shaped or spherical.

3. The method for preparing a high-efficiency nitrogen removal material for enhanced wastewater treatment according to claim 1, characterized in that: The porous powder is one or more of sawdust, straw pellets, and coconut shell powder.

4. The method for preparing a high-efficiency nitrogen removal material for enhanced wastewater treatment according to claim 1, characterized in that: The porous powder has a particle size of 100-150 mesh.

5. The method for preparing a high-efficiency nitrogen removal material for enhanced wastewater treatment according to claim 1, characterized in that: The particle size of sulfur powder is 150~250 mesh.

6. The method for preparing a high-efficiency nitrogen removal material for enhanced wastewater treatment according to claim 1, characterized in that: The limestone powder has a particle size of 150-250 mesh.

7. The method for preparing a high-efficiency nitrogen removal material for enhanced wastewater treatment according to claim 1, characterized in that: The foaming agent is one of sodium carbonate, sodium bicarbonate, animal keratin, and surfactant.

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